Glossary
Glossary terms found in the text are presented to help revise key terms and concepts
Example of Glossary taken from Attiwill- Ecology: An Australian Perspective.
Glossary
A
abaxial
Of a leaf; the surface that faces away
from the stem.
abiotic
Non-living.
abscission
The process of rejection of plant organs,
particularly the process that causes leaves to be shed from the plant as
litter. The process can be promoted by abscisic acid. (Allaby 1998)
absolute density
The actual abundance (as opposed to
relative abundance) of a particular species per unit area.
abyssal
Pertaining to the deepest part of the
ocean, below about 2000 m. (Allaby 1998)
adaxial
Of a leaf; the surface that faces the
stem
adiabatic lapse rate
The rate at which air cools when rising
adiabatically (that is, without exchanging energy with its surroundings)
through the atmosphere as a result of the utilisation of energy in expansion.
The adiabatic lapse rate for dry air is 9.8°C km-1. (Allaby 1998)
adsorbed
A particle of a particular substance is
adsorbed when it is physically bound to the surface of another particle or
substance by adhesion or penetration. In soils, adsorption is the attachment of
an ion, molecule, or compound to the charged surface of a particle, usually of
clay or humus, where it may be subsequently replaced or exchanged. (Allaby
1998)
aerobic respiration
Aerobic respiration (or mitochondrial
respiration) is an overall reversal of photosynthesis; it takes place in the
mitochondria of all living cells and results in gradual and controlled
oxidation of [CH2O] and the release of CO2 and energy as heat. By this process,
all of the biochemical processes necessary to maintain the living state are
sustained.
aestivation
Dormancy or sluggishness that occurs in
some animals during a period when conditions are hot and dry. Aestivation is
analogous to the hibernation some animals undergo in cold environments. (Allaby
1998)
age-specific
Of a demographic variable, a
characteristic that applies to a specific age-class-for example, death rates or
birth rates.
age-specific life-table
A table constructed by following the fate
of a cohort of animals over their lifetime.
age-structure
The distribution of individuals within a
population into defined age-classes.
alga (pl. algae)
Plants found mostly in freshwater and
marine environments; simple eukaryotic plants ranging from single-celled
organisms to large seaweeds. There is no differentiation in algae between stem,
root, and leaf.
Allee effect
The decline of growth rate of a
population arising from behavioural or ecological factors, such as difficulties
in finding mates in animals.
allele
One of two or more forms of a gene that
arise by mutation and occupy the same locus on homologous chromosomes. Common
shortening of the term ‘allelomorph'. (Allaby 1998)
allelochemical
A chemical substance released by a plant
that inhibits the growth or germination of another plant. The process is called
allelopathy.
alliance
A group of closely related plant
associations (where an association is described in terms of distinctive,
dominant species).
allometry
A differential rate of growth such that
the size of one part of the body changes in proportion to another part, or to
the whole body, but at a constant exponential rate. (Allaby 1998)
alpha diversity
The number of species within a given
habitat or site, usually written as α-diversity, and most simply called
‘species richness'.
alpine
Pertaining to the region above the
tree-line.
amensal interaction
An interaction between two species in
which species 1 depresses the population size of species 2, but species 2 has
no effect on species.
amensalism
An interaction of species populations, in
which one population is inhibited while the other (the amensal) is unaffected.
It is the opposite of commensalism.
amphibians
Chordates that are members of the class
Amphibia, possessing moist skin-for example, salamanders, frogs, toads.
amphipods
Animals in the peracarid crustacean order
Amphipoda that are small and laterally flattened.
angiosperms
Flowering plants; the ovules are borne
within the ovary. There are two groups: monocotyledons (single seed leaf) and
dicotyledons (two seed leaves).
anthropogenic
Used commonly (but not in the strict
sense) to describe substances and processes of human origin or that result from
human activity. (Allaby 1998)
arboreal
Of animals, tree-dwelling.
arenicolous
Of plants, preferring sandy soils.
argasids
Members of the order Acarina, which
contains ticks and mites. Argasids are large ticks that parasitise the skin of
many birds and mammals.
argillaceous
Of soils and sedimentary rocks; rich in
clay.
argillocolous
Of plants, preferring soils rich in clay.
aril
A fleshy and often brightly coloured
outgrowth from a seed. (Allaby 1998)
arthropods
Invertebrates with a hard external
skeleton and segmented body (for example, insects,crustaceans, spiders).
asexual reproduction
Reproduction without gametes (such as the
vegetative reproduction of plants from shoots arising from the stems and
roots).
associations
A plant association is a term that was
developed in the northern hemisphere. An association is a vegetative community
characterised by distinctive dominant species and is united physiognomically.
autochthonous
Literally, arising from the earth;
native.
autotroph
An organism that uses carbon dioxide as
its source of carbon; includes most plants and some bacteria. (Allaby 1998) The
autotroph derives its energy through the reduction of carbon.
avifauna
Birds.
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B
Batesian mimicry
Mimicking of brightly coloured, or
dictinctively patterned, unpalatable species by palatable species. This helps
protect the mimics from predators. (Allaby 1998)
benthic
Pertaining to the lowest region of a
freshwater or marine profile. Benthic organisms (referred to collectively as
the benthos) are those that dwell on the bottom or other substrate.
beta diversity
The number of habitats and the species
turnover between them (usually written as β-diversity).
bet-hedging
Reallocation of resources away from
stages of the life-cycle where uncertainty is greatest, as a result of natural
selection.
billabong
A watercourse that runs only after rain.
May be a waterhole, but generally an anabranch-that is, a water channel that
branches from the main watercourse and then rejoins it.
biodiversity
A portmanteau term that gained popularity
in the late 1980s, used to describe all aspects of biological diversity,
especially including species richness, ecological complexity, and genetic variation.
(Allaby 1998)
biogeography
The study of the geographical
distribution of plants and animals at different taxonomic levels, past and present,
the habitats in which they occur, and the ecological relationships involved.
(Allaby 1998)
biomass
The mass of living organisms or of a set
of organisms (such as a particular species) or of a component (such as leaves)
in an ecosystem. Biomass is literally ‘mass of living matter'. Increasingly,
biomass is used as a portmanteau term to describe matter of biological origin,
both living and dead.
biomass accumulation ratio
Of a plant community, the mean residence
time of carbon or dry matter. Dividing the standing biomass (kg m-2) by the net
annual rate of primary production (kg m-2 year-1) gives mean residence time in
years.
biome
A biological subdivision that reflects
the ecological and physiognomic character of the vegetation. Examples are
‘desert biome', ‘temperate evergreen forest biome' etc. (Allaby 1998)
biosphere
The part of the Earth's environment in
which living organisms are found. (Allaby 1998)
biota
The assemblage of plants and animals
occupying a place together. Examples are ‘marine biota', ‘desert biota' etc.
(Allaby 1998)
black body
An ideal black body is one that absorbs
all radiation falling upon it. Since this ideal black body will then have a
temperature above absolute zero, it will emit radiation (black body radiation),
the spectrum of this emission being a function of temperature.
bog
The main component of the alpine, wetland
complex, dominated by Sphagnum moss and hygrophilous (moisture-loving)
shrubs, and characterised by acidic, peat soils.
bolster heath
A specialised alpine community,
restricted to Tasmania, composed of small-leaved, dwarf shrubs that are
compressed into mounds or ‘cushions'.
boreal
Literally, pertaining to the north. The
boreal forest is the extensive, circumpolar, sub-Arctic forest of high northern
latitudes that is dominated by conifers. To the north it is bounded by tundra. (Allaby
1998)
Bowen ratio
The ratio of sensible heat flux (H)
to latent heat flux (LE).
bulk density
The mass per unit volume of soil.
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C
canid
A member of the family Canidae, which
contains dogs, foxes, and wolves.
carbon sequestration
A term used in the study of carbon
dioxide equilibria; generally used in relation to the long-term storage of
carbon in a forest (in living matter, litter, and soil). The carbon of carbon dioxide
is removed from the atmosphere by photosynthesis and stored (sequestered) in
the forest.
carnivore (adj. carnivorous)
An animal that takes flesh (meat) as the
major part of its diet; some plants are called carnivorous in that they trap
and digest insects.
carrying capacity
The maximum population of a given
organism that a particular environment can sustain; the K-value or saturation
value of the S-shaped curve of growth of a population. (Allaby 1998)
catchment
An area of land, the boundaries of which
are defined by relative elevation. The area from which a surface watercourse or
groundwater system derives its water. Catchments are separated by divides.
(Allaby 1998)
cation exchange capacity
A measure of the capacity of a soil to
exchange cations such as Ca2+, Mg2+, K+; usually written as CEC, and equal to
the sum of all exchangeable cations.
caudex (pl. caudices)
The thick, vertical trunk of palms and
ferns.
cetaceans
Fully marine, placental mammals,
including whales, dolphins, porpoises.
chamaephytes
Perrenials, herbs, or low shrubs with
perennating (regenerating) buds less than 0.25 cm above soil-level from which
they can resprout. One of the life forms of plants proposed by the ecologist C
Raunkiaer.
chenopod
A plant in the family Chenopodiaceae
(‘goose foot'), the saltbush family. henopod shrublands are extensive in some
of the drier parts of Australia, and they occupy some 7% of the mainland.
Two important genera are Atriplex (saltbush) and Maireana (bluebush).
Chenopods are also found in salt marshes. Australianchenopods have a high level
of endemism; a number of introduced chenopods are weeds that have become a
major nuisance in crops and disturbed habitats.
chernozem
A Russian term (‘black earth') used to
describe a soil that is dark-brown to black, neutral to alkaline, rich in
organic matter in the surface, and often associated with grasslands in
temperate regions.
chitons
Members of the phylum Mollusca, common on
rocky shores. Body is flattened, and covered dorsally by eight shell plates.
ciliate
Unicellular but highly differentiated
protozoa; the Ciliophora.
climate
The average weather conditions at a
particular place over a long period, usually more than 70 years (Allaby 1998).
climax
As defined by Clements (1916), the climax
is the end result of succession in which the vegetation is stable,
self-perpetuating, and harmonious, provided that the environment is also
stable.
closed-forest
A term used in Specht's (1970)
classification to define forest with a projected foliage cover of greater than
70%; synonymous with ‘rainforest'.
cluster roots
A root system that is characterised by
clusters of finely-divided and highly-branched roots, as in some members of the
Proteaceae (where the roots are called ‘proteoid roots').
cnidarian
Member of the invertebrate phylum Cnidaria,
containing a wide diversity of aquatic, soft-bodied forms. Examples include
jellyfish and corals.
CO2-equivalents
Used in discussions of global warming to express
in one figure the combined effects of all greenhouse gases. For example,
methane (CH4) is a much more powerful greenhouse gas than CO2, molecule for
molecule. A tonne of methane gas is equivalent to 23 tonnes of CO2 in its
greenhouse warming potential.
coccid
A homopteran insect of the family
Coccidae-for example, scale-insects.
coevolution
Evolution of species in close
association. Examples are prey and predators, plants and pollinators.
cohort
A term generally used to mean a group of individuals
of the same age.
colloidal fraction
The colloidal fraction of soil generally
applies to particles of diameter less than 1 μm.
commensal interaction
An interaction between two species in
which species 1 increases the population size of species 2, but species 2 has
no effect on species 1.
community
The assemblage of populations-plants, herbivores,
carnivores, decomposers-that inhabit a given environment; the biotic components
of an ecosystem.
competition
The interaction between individuals of
the same species (intraspecific competition) or between different species
(interspecific competition) in which the growth and survival of one or all
species or individuals is adversely affected. (Allaby 1998)
conduction
Thermal conduction is the transmission of
heat in a substance from higher to lower temperature.
congeneric
Of individuals, belonging to the same
genus.
coniferous
Of a forest, dominated by conifers.
conilurine
Rats of the subfamily Conilurini endemic
to Australia, including hopping mice, rock rats, and pseudo mice.
connectance
The actual number of connections between members
of a food web divided by the total possible number of connections.
connectivity
The extent to which the pattern of
habitats in the landscape reduces the effect of isolation.
conspecific
Of individuals, belonging to the same
species. (Allaby 1998)
contest competition
Contest competition occurs when organisms
harm one another while seeking shared resources, even if those resources are
not in short supply (also encounter, or interference).
continuous
Of a distribution, breeding is possible
over the entire range of a species.
contramensal interaction
(contramensalism)
An interaction between two species in
which species 1 benefits directly at the expense of species 2. General term for
the +/- interaction pair that includes many trophic interactions like
predation, herbivory, and parasitism.
convection
Transfer of heat by movement of a liquid
or gas. For example, air that has been heated expands, becomes less dense, and
rises, transferring heat in a convection current.
convergent evolution (convergence)
The development of similar
characteristics in organisms that are unrelated (except through distant
ancestors) as each adapts to a similar way of life in similar environments
(Allaby 1998). For example, convergent evolution predicts that communities in
deserts in Australia and southern Africa, or in grasslands in Australia and
North America, should show parallels in structure and ‘balance' in terms of
species and trophic organisation.
cooperative breeding
Cooperative breeding occurs in species in
which the young remain with parents and help raise their younger siblings.
coral bleaching
The loss of pigments and microscopic
plant cells from coral tissues that results in the whitening of the coral.
Bleaching is caused primarily by rising temperatures of the surface layers of
the sea, and also by changes in salinity, increases in sedimentation, and
decreases in light. There are worldwide concerns that increased bleaching of coral
is linked with global climate change, high temperatures and El Niño.
(Australian Institute of Marine Science, www.aims.gov.au)
corals
Members of the phylum Cnidaria that
secrete a calcium carbonate cup that en masse make up coral reefs, filter
feeding but also relying on symbiotic microalgae.
corvids
Member of the family Corvidae, which
contains crows and ravens.
cosmopolitan
A distribution of an organism that is
worldwide. (Allaby 1998)
cotyledons
The part of the plant embryo from which leaves
are formed. Monocotyledons have one cotyledon in each seed; dicotyledons have
two.The cotyledons of many plants emerge abovethe ground after germination, and
become photosynthetically active and are essential to early growth and
establishment.
critical weight range
Australian mammals weighing 35-5500 g, prone
to declines and extinction since European settlement. (Burbidge & McKenzie
1989)
crude birth rate
Births per 1000 of population per unit
time.
crude density
Number of individuals per hectare, even
though a significant proportion of the area may not be suitable habitat.
crustaceans
Subphylum of Arthropods with antennae, mandibles,
and maxillae-for example, crabs, shrimps, slaters.
cryptic
Concealed; describes an organism whose
colour, pattern, or shape blends in with its surroundings.
crytophytes
Plants with perennating buds below the
surface of the soil or below water-level from which they can resprout. One of
the life forms of plants proposed by the ecologist C Raunkiaer.
cyanobacteria
Single-celled, photosynthetic, blue-green
bacteria, formerly regarded as blue-green algae. Many can fix atmospheric
nitrogen. Cyanobacteria are usually free-living, but some can enter into mutualistic
associations with fungi to form lichens.
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D
dasyurid
Member of the marsupial family
Dasyuridae, which contains many small and medium-sized species. All eat insects
and other invertebrates and/or meat.
deciduous
Of a plant, losing all of its leaves each
year.
decomposers
Organisms (mainly bacteria and fungi)
that consume non-living organic matter for their energy.
decomposition
The oxidation of non-living organic
matter by decomposers. The C is released as CO2, and elements bound in organic
forms are mineralised to simple ions, available again for uptake. Almost all of
net primary production is eventually decomposed. Decomposition is the key
process that regulates the rate of nutrient cycling.
demographic failure
Extinction due to death of all members of
a taxa-for example, after a catastrophe.
demographic stochasticity
A term describing the fluctuations in
populations where birth or death rates vary randomly.
demography (adj. demographic)
Study of the size, structure, and changes
of populations.
dendrogram
A diagram, like the branching of a tree (dendro-),
that represents relationships between groups (of taxa, of communities). Groups
that are more closely related are shown as sharing branches or branchlets.
density
Number of individuals per unit area.
density-dependent factors
Limiting factors that come into play as
the density of the population increases (for example, food supply).
density-independent
Limiting factors that come into play independently
of the density of the population (for example, cold weather).
desiccation
The drying of an organism in its
environment. For example, desiccation of plants in a severe drought can lead to
all of the leaves being killed and falling as litter. Prolonged desiccation can
lead to death of the plant.
deterministic
Of an outcome, predicted given specific
initial conditions.
diapause
Suspended growth or development, usually
of an embryo.
diatoms
Microscopic algae (phytoplankton);
goldenbrown algae of the division Bacillariophycae. Most are unicellular and
most are photosynthetic. Can form chains.
dicotyledon
That class of flowering plants
(angiosperms) that has two seed leaves (cotyledons) in the embryo. Eucalypts,
wattles, banksias, and many other groups are all dicotyledonous. The
abbreviation ‘dicot' is commonly used.
differentiation
The gradual production of differences
between the descendants of the same ancestral type. (‘The Shorter Oxford
English Dictionary', Clarendon Press, Oxford, 1973)
dimorphism
The presence of one or more morphological
(physical) differences that divide a species intotwo groups. (Allaby 1998)
dinosaurs
Reptiles, frequently of enormous size;
the dominant land animals of the Cretaceous and Jurassic periods but now
extinct.
diprotodon
A member of the extinct mammal genus Diprotodon,
resembling giant wombats.
diprotodonts
Herbivorous marsupials of the order Diprotodonta,
which includes gliders, possums, kangaroos, wallabies, the koala, potoroos, bettongs,
wombats.
disjunct
Of a distribution, populations of a
species are separated over the range of the species in such a way that breeding
between populations is not possible.
dispersal
The spread of organisms or propagules to
a new area.
disturbance
Any relatively discrete event in time
that disrupts ecosystem, community, or population structure, and changes
resources, substrate availability, or the physical environment. For example,
bushfire is a common and regular disturbance in many Australian ecosystems.
Tropical cyclones are a disturbance in the northern rainforests.
diversity
The species richness of a community.
dormancy
A period of inactivity. Some animals
remain dormant during periods of environmental stress. The seeds of some plants
remain dormant until the dormancy is broken by specific environmental triggers.
dromornithids
Flightless birds, long extinct. Dromornis
stirtoni was among the largest birds ever known.
dryland salinity
Salinity that results when deep-rooted
vegetation is replaced by shallow-rooted pastures or crops that do not use all
of the rainfall. The watertable rises, mobilising salt to the upper layers, and
evaporation at the soil surface leaves an accumulation of dried salt.
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E
ecological density
The density per unit area of suitable
habitat.
ecology
The scientific study of the
interrelationships among organisms and between organisms, and between them and
all aspects, living and nonliving, of their environment.
ecosphere
The part of the Earth's environment in
which living organisms are found, synonymous with biosphere. The term
‘ecosphere' puts greater emphasis on the interconnection between the living and
non-living components. (Allaby 1998)
ecosystem
The whole complex of living and
non-living components that interact to form a system.
ecosystem diversity
The variety of habitats, biotic
communities, and ecological processes. (Environment Australia 2002)
ecotone
A narrow and fairly sharply defined
transition zone between two or more different communities. Such edge communities
are typically species-rich. (Allaby 1998)
ecotype
A locally-adapted population that is morphologically
recognisable from other populations of the same species. Ecotypes can reproduce
with other ecotypes of the same species. (Allaby 1998)
ectomycorrhiza
A type of mycorrhiza in which the fungal
hyphae or filaments do not penetrate the cells of the root, but cover the
surface of the root and grow between the root cells. This type of mycorrhiza is
common in forest trees. (Allaby 1998)
edaphic
Of the soil, or influenced by the soil.
edge effect
A region of species richness where two communities
overlap.
El Niño-Southern Oscillation (ENSO)
An irregular, but natural, feature of the
global climate system, resulting from interactions between the oceans and the
atmosphere across the Indo-Pacific region of the planet. After the seasonal
cycle and the various monsoon systems, ENSO is the next major phenomenon that
dominates the Earth's year-to-year climatic variability.
elaiosome
An oil-filled projection from a seed or
fruit. Ants are particularly attracted to elaiosomes of seeds.
embryonic
As an embryo.
emigration
Movement out of a population.
endemism (endemic)
Of a species, the state of being native
to a particular region. In contrast, a widely distributed species is described
as pandemic, and a species (such as some weeds) that occurs around theworld is
called cosmopolitan.
endogenous
Literally, arising from within. Often
applied to disturbance-for example, the fall of a large, old tree, creating
space for regeneration, is an endogenous disturbance.
endomycorrhizas
A type of mycorrhiza in which the hyphae
or filaments of the fungus penetrate the cells of the root. Common in many
plants. (Allaby 1998)
endoparasites
Parasites that live within the body of their
host organisms.
endosymbiotic
Organisms (for example, bacteria) that
live symbiotically inside the cells of the host organism. Both species benefit
from the association.
environmental stochasticity
Random fluctuations of environmental parameters.
environmental weed
A plant that is recognised as a weed in a
community of native vegetation. Very nearly all vegetation communities now
include introduced species. Some of these invaders are so vigorous that they
threaten the survival of whole ecosystems. Environmental weeds are a serious conservation
problem in Australia.
ephemeral
Short-lived.
epicormic
A term describing the dormant buds on a
stem. After fire, these dormant buds are stimulated (apical dominance has been
temporarily destroyed), and the shoots are called ‘epicormic shoots'.
epiphyte
A plant that uses another plant for its
physical support, but which does not draw nourishment from it.
erythema
Redness of the skin. Erythemal radiation
(for example, ultraviolet radiation) is radiation that causes reddening of
skin.
eukaryotic
Of organisms, with a true nucleus, and
with organelles bounded by a membrane.
eutrophication
The process of nutrient enrichment
(usually nitrates and phosphates) in aquatic ecosystems, such that the
productivity of the system ceases to be limited by the availability of
nutrients. (Allaby 1998)
evapotranspiration
The evaporation of water from both soil
and leaves.
evergreen
Of perennial plants, retaining green
leaves throughout the year.
exchangeable cations
Cations associated with charged soil
colloids that can participate freely in ion exchange (Leeper & Uren 1993). The major
exchangeable cations are Ca2+, Mg2+, K+, and Na+.
exogenous
Literally, coming from without. Often
applied to disturbance-for example, a hurricane that temporarily destroys
forest structure, thereby allowing space and resources for regeneration, is called
an exogenous disturbance.
exoskeleton
Skeleton on the outside of the body; as
found, for example, in insects, crabs, molluscs, tortoises.
exploitation competition
An interaction in which organisms harm
one another by using shared resources that are in short supply (also resource
or scramble).
exponential growth
(Mathematical function describing a)
growth rate that increases as the size of the population increases, and is
calculated as a fixed proportion of the starting value.
extinction
Elimination of a taxon. Extinction can
occur if the taxon disappears, or if it is replaced by selection with another
taxon.
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F
facultative
Having the ability to adopt alternative
processes. A facultative parasite can live either parasitically or independently.
fecundity
The numbers of offspring that are
produced over a certain period of time.
fecundity table
A table of number of births for each female
age-class.
feldmark
A specialised alpine community
characterised by dwarf shrubs that form patterns of alternating stripes of
vegetation and bare, stony ground; restricted to high-altitude, wind-exposed
alpine sites, or to late-lying snow patches.
felid
Member of the family Felidae, which
contains house cats and their larger relatives such as lions and tigers.
fen
Part of the alpine, wetland complex,
characterised by free-standing water and usually dominated by sedges, and
having alkaline to slightly acidic organic soils.
feral
Of plants and animals, the reversion of a
domesticated plant or animal to a wild state (for example, feral cats, feral
goats).
ferrosol
A friable, red-brown soil, acidic
throughout the profile, with little change in texture down the profile; from
the Australian soil classification of Isbell (1996). Many of the deep,
red-brown soils of the Great Dividing Range are ferrosols.
field capacity
The amount of water that a soil can hold
in the field, as measured two days after saturating rain or irrigation.
fine earth
The fraction of soil that passes through
a 2 mm sieve. The soil is first air-dried, and the soil aggregates are ground.
The fine earth is used for many chemical analyses.
fire regime
The historical fire regime for a given
community is defined by the components intensity, type, frequency, and season.
These components are also used in developing fire regimes for management (prescribed
or controlled fire).
firn
Firn is a porous layer (typically 40-100
m thick) of compacted snow overlying an ice sheet. Air in the open channels in
firn is in contact with the atmosphere, and variations in atmospheric
composition diffuse slowly through the firn column.
fitness
Ability to leave viable offspring.
floristics
A general term used in discussing the
vegetation of a given area.
formation
The highest level of a vegetation
hierarchy, defined by physiognomy (growth form and structure)- for example,
grassland, shrubland, woodland, tall open-forest.
fossorial
Of an animal, adapted for digging and
burrowing.
fragmentation
The process where a continuous habitat,
such as forest, shrubland, or grassland, is subdivided into a number of
separate components. It is a dynamic process, resulting in a changing pattern
of habitats in the landscape through time.
free energy
A measure of the capacity for work. G =
H - TS, where G = free energy, H = enthalpy, T =
absolute temperature, and S = enthalpy. (Emiliani 1987)
frugivore (adj. frugiverous)
An animal that takes fruit as the major
part of its diet.
fucalean
A brown alga, such as kelp, in the order
Fucales.
functional groups
A group that includes animals that have
similar functions. For example, the group ‘carnivores' is a functional group
that includes meat-eaters.
fynbos
A South African term for heathlands.
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G
gamma diversity
The turnover within a habitat from one
area to another (usually written as γ-diversity).
gene pool
The genetic resources of a population.
generalist
A species that uses a wide range of
resources (such as food and shelter).
genet
A genetic individual; the product of a
zygote. (Allaby 1998)
genetic distinctiveness
The genetic composition that maintains a species
distinct from other species. If the genetic distinctiveness of the species
becomes swamped by interbreeding with other species, then the species becomes
extinct.
genetic diversity
The variety of genetic information
contained in all of the individual plants, animals, and microorganisms that
inhabit the Earth. Genetic diversity occurs within and between the populations
of organisms that comprise individual species as well as among species.
(Environment Australia 2002)
genetic drift
The random fluctuations of gene
frequencies in a population such that the genes among offspring are not a
perfectly representative sampling of the parental genes.
genome
The total genetic information carried by
a single set of chromosomes (i.e. in a haploid nucleus). A single
representative of each of all of the chromosome pairs in a nucleus will
therefore bear the genome of an individual.
genotype
The genetic constitution of an organism,
as opposed to its physical appearance (phenotype). (Allaby 1998)
geographic information systems (GIS)
A computer-based system in which a
hand-held instrument reads basic geographical information (latitude, longitude,
altitude) from a satellite positioning system and geological, biological, and climatic
data can be entered.
geomorphology
The study of the physical features of the
Earth's surface, and of their relationship with the underlying geology.
glaciation
The covering of a landscape or larger
region by ice; an ice age. (Allaby 1998)
graminoid
Of the family of the grasses (Gramineae).
greenhouse effect
The atmosphere contains gases (carbon
dioxide, water vapour, ozone, methane, nitrous oxide)that are transparent to
incoming, short-wave radiation, but that absorb long-wave radiation emitted by
the Earth (wavelength of maximum emission is close to 10 μm). Thus some of the
energy emitted by the Earth is absorbed (‘trapped') by the atmosphere, much as
the glass traps heat within a greenhouse. The analogy does not hold completely;
the high temperatures reached in a greenhouse are due in large part to the closed
structure that prevents mixing of the heated air within the greenhouse with the
external atmosphere.
greenhouse gases
Carbon dioxide, water vapour, ozone,
methane, nitrous oxide, all trace gases in the atmosphere, are transparent to
incoming, short-wave radiation, but absorb long-wave radiation emitted by the
Earth-the greenhouse effect. While most attention has been given to CO2, 20% of
the total direct radiative forcing is due to methane (CH4), the concentration
of which has risen from700 parts per billion (ppb) in the mid 1700s to 1700 ppb
in the late 1900s. CH4 is produced in many ecosystems (particularly wetlands)
but the increase is due to human activities such as livestock farming (enteric
fermentation) and rice farming. (Houghton et al. 1996)
gross reproductive rate
The mean number of females born in each
age group.
groundwater
Free water below the soil surface.
guild
A group of species, all members of which
use the same food, shelter, and other resources in a similar way.
gymnosperms
Conifers and their allies; primitive seed
plants, distinguished from the angiosperms by having the ovules borne
unprotected.
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H
habitat
The living place of an organism or
community, characterised by its physical (for plants) or vegetative (for animals)
properties. (Allaby 1998)
halophytes (adj. halophytic)
Terrestrial plants that are adapted morphologically
and/or physiologically to grow in salt-rich soils and salt-laden air. (Allaby
1998)
heliothermic
A term describing a subsurface stratum of
a lake that is raised in temperature by absorption of the sun's energy.
hemicryptophytes
Perrenial and biennial, herbaceous plants
with perennating (regenerating) buds at soil-level. This shoot dies
periodically, when conditions are unfavourable. One of the life forms of plants
proposed by the ecologist C Raunkiaer.
Hemiptera
An order of insects; bugs.
herbivore
An animal that obtains its energy by
feeding on green plants, which are the primary producers. (Allaby 1998)
hermaphrodite
An individual that possesses both male
and female sex organs-that is, it is bisexual. (Allaby 1998)
heterogeneous
Variable.
heterosis
The increased growth, survival, and
fertility of hybrids, as compared with the two zygotes. Also known as ‘hybrid
vigour'.(Allaby 1998)
heterotherm
An animal whose body temperature
fluctuates more or less with that of the surrounding environment.
heterotroph
An organism that is unable to manufacture
its own food from simple chemical compounds and therefore consumes other
organisms, living or dead, as its source of carbon (Allaby 1998). The heterotroph
derives its energy from the oxidation of organic matter.
heterozygosity
Measure of genetic variation in an
individual or population.
homeostasis
The tendency of a biological system to
resist change, thereby maintaining itself in a state of stable equilibrium.
(Allaby 1998)
homeotherm
An organism whose body temperature varies
only within narrow limits. Body temperature is regulated by internal mechanisms
(endotherm) or by behavioural means (ectotherm) or both (for example, humans
are endotherms, but we use
fires and heavy clothes to keep warm in
winter).(Allaby 1998)
homoclime
Areas separated in space that have
similar climates.
homopterans
Insects belonging to a group within the
order Hemiptera that contains a wide variety of species that feed on plant
products. Examples are aphids, greenfly, and cicadas.
horizon
Applied to soils, meaning a relatively
uniform layer of soil that is physically, chemically, and/or biologically
distinguishable from the layers above and below it. (Allaby 1998)
hybridisation
The production of an offspring of
genetically dissimilar parents. Mostly used to describe the production of
offspring of two different species or of two distinct varieties within a
species.
hydrobiid
Hydrobiid snails (Gastropoda: Rissoacea)
are a group of freshwater molluscs. They are small, usually conical, and of
special interest because many species have very restricted ranges, providing
not only special conservation concerns but also intriguing evolutionary
questions.
hydrophytes
Plants that grow in water or very wet
places.One of the life forms of plants proposed by the ecologist C Raunkiaer.
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I
imbricate
Overlapping. Describes the habit of
plants that repeatedly fall over and re-shoot from the fallen stem, thereby
creating an impenetrable thicket.
immigration
Movement into a population.
incidence function
Refers to the frequency of occurrence of
a species in habitat isolates grouped in relation to their size, isolation, or
other characteristic.
index (pl. indices) of abundance
Estimate of the relative size of
populations (such as the number of fish captured per unit of fishing time or
kangaroos observed per hour of survey time).
innate capacity for increase
The instantaneous rate of increase
attained by a population that is growing in an optimal environmental
conditions, not limited by resources, competitors, or predators.
insectivore (adj. insectivorous)
An animal that takes insects or other
arthropods as its main food supply.
interference competition
An interaction in which organisms harm
one another while seeking shared resources, even if they are not in short
supply (also encounter or contest).
inter-generational equity
The principle that the present generation
should ensure that the health, diversity, and productivity of the environment
is maintained or enhanced for the benefit of future generations.
interglacial
The period between glacial events.
interspecific competition
Competition between individuals of
different species.
intraspecific competition
Competition between individuals of the
same species.
intrinsic rate of increase
R, a measure of instantaneous rate of change of a population
per individual, related to the reproductive capabilities of the species, and affected
by the environment.
invertebrates
Animals without a backbone-for example, insects,
worms, spiders, crustaceans, molluscs.
irrigation salinity
Salinity that results when excess water
is applied to irrigated land. The water table rises, mobilising salt to the
upper layers. Water at the soil surface evaporates, leaving a layer of dried
salt.
isomorphous substitution
A term applied to the formation of a clay
mineral in which atoms of a similar size replace or substitute one another. For
example, Si4+ may be replaced by Al3+,
Al3+ may be replaced by Mg2+.
iteroparity
Repeated breeding over a life-time.
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key factor analysis
An analysis in which the mortality rates
at different stages in the life history of a species are determined, so that
those stages that will havethe largest impact on the growth rate of the population
can be identified.
keystone species
A species, the presence or abundance of
which can be used to assess the extent to which the resources of an area or
habitat are being exploited. (Allaby 1998)
Kirchhoff's law
A law in physics that states that the
effectiveness of a body in absorbing radiation of a given wavelength is the
same as its emissivity at that wavelength.
krasnozem
A krasnozem (Russian for ‘red soil') is a
friable soil, dominantly red, acidic throughout the profile, with little change
in texture down the profile. In the modern, Australian classification (Isbell
1996) these soils are classified a s ‘ferrosols'. Many of the deep, red-brown
soils of the Great Dividing Range are krasnozems or ferrosols.
K-selection
Selection for maximising competitive
ability. A K-selected species is one in which the population size is
maintained close to the carrying capacity(K) of the habitat for that
species
K-T boundary
The boundary between the Cretaceous and Tertiary
epochs. The K-T boundary is recognised globally as a time of mass extinction,
probablyassociated with the impact of a massive comet or meteor.
kwongan
A word of Aboriginal origin used to
describe the heathlands of southern Western Australia.
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L
latent heat of vaporisation
The amount of energy exchanged as water changes
state to water vapour (and vice versa); L = 2442 J g-1.
laterite (adj. lateritic)
A term used in Australia to describe old
soils dominated by ironstone. The soils are deeply weathered; they ‘represent
old landscapes which remain as uplifted plateaus which are only slowly eroded
because the ironstone is physically and chemically persistent. Large areas of
lateritic country occur in present-day dry climates. The laterite is a relict
of a former wet climate.' (Leeper & Uren 1993).
layers
Strata in a plant community, such as
‘overstorey', ‘understorey', ‘shrub layer', and ‘ground layer'.
liane
A climbing plant found in wetter forests,
with long, woody, rope-like stems.
LIDAR (Light Detection and Ranging)
A measurement system that records the
strength of timed pulses of laser light to determine distances, among other
attributes. These are processed by software packages to provide data such as
altitude of the ground surface, plant canopy height, sub-strata height and
depth, crown cover, leaf and stem biomass, and clumping and gaps in crowns.
Currently data are obtained from sensors flown in aircraft, much as aerial photographic
data are obtained. In some systems these can be linked at time of recording to
GIS and digital imagery to enhance subsequent analysis.
life-table
A table that shows the mortality within a
population for each age class.
lignotuber
A large, woody swelling that arises in
the axils of cotyledons, usually found just below the soil surface. The
lignotuber contains numerous dormant buds that develop new shoots if the original
shoot is burnt or grazed. Lignotubers are not present in all eucalypts but are
relatively common in species of open-forests.
lithology
The study of rocks.
lithosphere
More or less synonymous with Earth's
crust; the outer layer of soil and rock.
littorinids
Marine herbivorous snails, members of the
phylum Mollusca. For example, the familiar blue periwinkles found high on
seashores are littorinids.
logistic growth curve
Mathematical description of the growth
rate of a population that initially increases exponentially, but whose growth
is limited by factors such as resources.
long-wave radiation
Thermal radiation, predominantly in the wavelengths
3-100 μm.
lycaenid
Member of the family Lycaenidae, which
contains many large and brightly-coloured species of butterflies.
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macrofossils
Fossils that are large enough to be
visible and identifiable by eye.
macronutrients
An element that is essential for the
growth and reproduction of organisms, and that is required in relatively large
amounts.
macropod
Marsupial with large hind limbs and feet,
belonging to the family Macropodidae-for example, kangaroos, wallabies.
macropores
Large pores of a soil (> 30 μm);
macropores do not hold water when the soil is at field capacity.
mammals
Members of the Mammalia, a class that is distinguished
by (among other things) the secretion of milk, possession of hair (at some time
in life), and a lower jaw consisting of a single pair of bones.
marsupial
Mammals of the subclass Marsupialia whose
young are born at an early development stage.
matric potential
The component of the water potential of a
soil that is due to the forces of adsorption and capillarity. The water
potential of soil water decreases in proportion to the decreasing size of soil
pores (that is with increasing force of capillarity).
mean residence time
The mean residence time (of carbon, dry
matter) of a plant community is obtained by dividing the standing biomass (kg
m-2) by the net annual rate of primary production (b kg m-2 year-1) to give mean
residence time in years.
megachiropteran
Member of the suborder Megachiroptera.
All members are medium-sized to large bats, such as flying foxes and blossom
bats.
megafauna
Very large animals.
megatherm
A plant of the warmest (tropical)
environments.
mesic
Of an environment, neither very wet nor
very dry.
mesomorphic
Having characteristics that indicate
dependence on a continuous supply of water.
mesopredator
Medium-sized predator, often ranging in
size between a rat and a house cat.
mesotherm
A plant of warm-temperate areas, neither
very wet nor very dry.
metamorphic rock
A rock or rock formation that has been
changed (transformed) by heat or pressure.
metamorphosis
An abrupt change in physical form.
metapopulation
A group of subpopulations interconnected
by dispersal.
metastability
Of a system that is apparently stable at
one scale, but the components of which are not necessarily at a stable
position.
microchiropteran
Member of the suborder Microchiroptera.
All members are small bats, such as horseshoe bats and little forest bats.
microclimate
The climate of a particular habitat.
micronutrients
An element that is essential for the
growth and reproduction of organisms, but that is required in relatively small
amounts.
micropores
Small pores of a soil (< 0.2 μm);
micropores hold water when the soil is at wilting point.
microtherm
A plant requiring a cold habitat for
growth.
microtine
Of the rodent subfamily Microtinae-for example,
lemmings.
mineralisation
The process whereby elements bound in organic
structures are converted back to simple ionic form, available again for uptake by
plants.
mites
Arachnid animals that are very common on
plant surfaces and in soils or sediments.
mitochondrial respiration
Aerobic respiration (or mitochondrial
respiration) is an overall reversal of photosynthesis. It takesplace in the
mitochondria of all living cells and results in gradual and controlled
oxidation of [CH2O] and the release of CO2 and energy as heat. By this process,
all of the biochemical processes necessary to maintain the living state are
sustained.
modular organism
An organism in which the zygote develops
into a discrete unit that then produces more units like itself, rather than
developing into a complete organism. Modular organisms (e.g. plants, fungi, sponges)
usually have a branching structure and an overall shape that is highly variable
and mainly determined by environmental
influences. (Allaby 1998)
molluscs
Members of the phylum Mollusca:
invertebrates possessing a muscular foot and usually calcium carbonate shells.
Includes snails, slugs, mussels, octopuses, chitons, tusk shells, and so on.
momentum
The product of mass and velocity, a
quantity or measure of motion that is conserved in physical systems where no
external forces are acting. For example, a body of moving air can only lose
speed or change direction by transferring momentum to its surroundings (other
air masses, landforms, vegetation, and so on).
monoclimax
The monoclimax theory of Clements (1916)
is that all successions in a given area will ultimately converge towards a
single climax community, determined by the climate of the area-hence the monoclimax,
or climatic climax.
monocotyledons
That class of flowering plants
(angiosperms) that has only one seed leaf (cotyledon) in the embryo. The palms,
grasses, lilies, and other groups of smaller plants are all monocotyledonous.
The abbreviation ‘monocot' is commonly used.
monogamy
Breeding pattern where mates pair
exclusively, either through a breeding season or for life.
monotremes
Egg-laying mammals of the order
Monotremata- that is, echidna, platypus.
montane
Of the mountains.
morphology (adj. morphological)
Form or shape.
morphospecies
Many species do not yet have scientific
names but can be delimited consistently as ‘morphospecies', or ‘recognisable
taxonomic units' (RTUs). This approach enables ecologically informative groups
such as ants to be used effectively in environmental assessment.
mortality
Death.
mortality rate
Number or proportion of organisms dying
over a defined time period.
muricid
Marine, carnivorous snails, members of
the phylum Mollusca; important intertidal predators.
murid
Rodents of the family Muridae-for
example, rats and mice.
mustelid
Member of the family Mustelidae, which
includes weasels, stoats, and their larger relatives.
mutation
(1) A change in the structure or amount
of the genetic material of an organism. (2) A gene or chromosome set that has
undergone a structural change. (Allaby 1998)
mutualism
Interaction between species that benefits
both.
mycorrhiza
A close association between a fungus and
the roots of a plant, from which both the fungus and the plant benefit
nutritionally. (Allaby 1998)
myrmecochory
Dispersal of spores or seeds by ants.
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N2-fixation
The transformation of N2 gas in the
atmosphere to ammonia. This is a chemical reduction. In addition to the N2 gas
that is fixed by atmospheric processes, N2 gas is fixed by certain
microorganisms, both free-living and in symbiotic association with the roots of
plants. For example, the nitrogen-fixing bacteria Rhizobium forms nodules
in the roots of many leguminous species (such as Acacia), and a
nitrogen-fixing actinomycete forms nodules in the roots of Casuarina.
natality
Birth.
nectivore (adj. nectivorous)
An animal that takes nectar and pollen as
the major part of its diet.
negative feedback
A control mechanism where a change in a
variable (e.g. population increase) sets off a response that counteracts the
initial change. In a system, the mechanism by which a process is limited internally-that
is, without reference to factors outside the system. Ecologically such
mechanisms favour the maintenance of equilibrium in organisms, populations, and
ecosystems. (Allaby 1998)
net primary production (NPP)
The net rate of productivity of the
primary producers (plants), given by NPP = PG - R, where PG is the rate of
gross photosynthesis and R is the rate of respiration of the cells of all parts
of the plants. Thus NPP is that part of gross photosynthetic production that is
not respired by the plant and hence becomes available for utilisation by all
the dependent heterotrophs of the ecosystem.
net radiation
Net radiation at a specific point is
given by (shortwave radiation in - short-wave radiation out) + (long-wave
radiation in - long-wave radiation out). Short-wave (solar) radiation is that
within the wavelengths 0.3-3 μm; long-wave (thermal) radiation is predominantly
within the wavelengths 3-100 μm.
net reproductive rate
Mean number of females born in each age
group multiplied by their survival rate.
niche
A species' ‘role' in a community.
Introduced initially as a synonym of ‘habitat', but now used with a more
functional interpretation incorporating relationships of a species with food,
natural enemies, and other environmental attributes-the understanding that a
species' niche is in part the outcome of relationships with other species.
noctuid
Member of the family Noctuidae, which
contains a large number of moth species.
nomadic
Of individuals or populations; not
inhabiting the same region through life; migratory.
non-equilibrium dynamics
The situation where individual
populations do not reach equilibrium (for example, due to extinction), but the
metapopulation continues.
non-sprouters
Synonymous with ‘seeders'; plants that
regenerate by germination from seed.
noxious
Poisonous.
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obligate
Only by this process. An obligate
parasite can live only by parasitism. An obligate seeder can reproduce only by
seed.
omnivore (adj. omnivorous)
An animal that feeds on animals, plants,
seed, fungi.
orographic
Caused by the features of mountains,
usually applied to the physical effect mountains have on climate.
ostracod
A crustacean in the class Ostrocoda; very
small organisms with a hinged shell-for example, seed shrimps, shell shrimps.
overstorey
The top canopy layer of a forest,
consisting of the dominant trees.
oxisol
Soil order classified according to Soil
Taxonomy (the classification system developed in the United States). Red to
brown soil, rich in free iron oxide, with little contrast in texture between A
and B horizons. In the modern, Australian classification (Isbell 1996) these
soils are classified as ‘ferrosols' (see also ‘krasnozem').
ozone-depleting substance
Refers to chemicals, regulated under the
Montreal Protocol, that deplete stratospheric ozone.
ozone-depleting potential
Refers to the ability of an
ozone-depleting substance to deplete stratospheric ozone relative to CFC-11
ozone hole
A progressive loss of ozone is observed
at mid and polar latitudes, with particularly severe losses (more than 60%)
over Antarctica, the so-called Antarctic ‘ozone hole'. The hole is defined as
the region where total ozone levels are less than 220 Dobson units.
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palaelodids
Flamingo-like birds that persisted into
the Pleistocene, and then became extinct.
palynology
The study of pollen grains in ancient
peats and sedimentary rocks, from which past floras can be reconstructed.
pandemic
Of a distribution; prevalent over the
whole of a country or a continent, or over the whole world.
parasite
An organism that lives in or on another
organism. Parasitism usually implies that some harm is done; harm varies from
negligible to acute and eventual death. (Allaby 1998)
parasitism
An interaction of species populations in
which one (typically small) organism (the parasite) livesin or on another (the
host), from which it obtains food. Whereas a predator kills its host a parasite
does not. (Allaby 1998)
parent material
The material-rock or sediment-from which
a soil has formed.
passerine
A bird in the order Passeriformes,
perching birds, the order that contains more than one-half of all bird species.
pathogen
A micro-organism that causes disease.
pedality
A soil characteristic, meaning the
particles are aggregated into larger units.
peneplain
A flat, featureless landscape formed by a
long history of erosion.
perennial
A plant that continues to grow from year
to year.
phanerophyte
Woody plants with perennating
(resprouting) buds borne more than 0.3m above soil level. One of the life forms
of plants proposed by the ecologist C Raunkiaer.
pest
Used here to mean those organisms that
are seen to be deleterious to either the economicor aesthetic well-being of
humans, or to other environmental components that humans value- those organisms
that interfere with processes of food production or that devalue our aesthetic concept
of cultural landscapes, be they gardens, parklands, or native ecosystems.
phenology
The timing of events in relation to
season-for example, in plants, the timing of litterfall and of flowering; in
animals, the timing of migration and of changes in morphology.
phenotype
The appearance of an individual, the
expression of both genetic inheritance and environmental influences.
philopatry
The tendency of an individual to return
to or stay in its home area (Allaby 1998).
photon
An amount of energy = hν, where h
= Planck's constant and ν is the frequency of the electromagnetic
radiation. The energy of one mol of quanta (or Einstein) = Nhν, where N
= Avogadro's number.
photorespiration
The process in which the primary
carboxylating enzyme in photosynthesis (ribulose-1,5- bis-phosphate, RuBP)
carboxylase acts as an oxidase that oxidises the same acceptor as in photosynthetic
carboxylation, with the release of CO2. In the absence of O2, or in the
presence of high CO2, both of which favour the carboxylase reaction, plants
that possess only the RuBP carboxylating enzyme grow faster.
photosynthesis
The reduction of atmospheric CO2 by green
(chlorophyll-containing) plants, using energy from solar radiation that is
captured by the chlorophyll molecule.
photosynthetically active radiation
Generally written as PAR; radiation in
the wavelengths λ = 400-700 nm (the visible wavelengths) that is absorbed by
the chlorophyll molecule.
physiognomy
The form and structure of natural
communities.
phytoplankton
Microscopic aquatic plants that drift
with water movements. Diatoms are the main component of phytoplankton; they are
photosynthetic, and formthe basis of aquatic food-chains.
piscivore (adj. piscivorous)
An animal that takes fish as the major
part of its diet.
placental
Mammals that give birth to live young and
have a placenta for the development of the foetus.
pneumatophores
Vertical roots that extend out of the
sediment and water in mangrove forests. Pneumatophores facilitate the exchange
of gases between the atmosphere and the submerged roots in the (mostly)
anaerobic sediments.
podzol (podsol)
A Russian term used to describe soils
with an acidic, grey sandy or loamy surface soil, often with a bleached layer
immediately below, and a marked change in texture to a clayey sub-soil. In the
modern, Australian classification (Isbell 1996) these soils are classified as
‘podosols'.
polygynous
Animal mating-pattern where males mate
with more than one female.
polymorphism
(1) The existence of two or more forms
that are genetically distinct from one another, but are contained within the
same interbreeding population. (2) In social insects, the presence of different
castes within the same sex. (Allaby 1998)
polyprotodont
A marsupial having more than one pair of functional
lower incisors-for example, bandicoots, marsupial mice.
population
A group of organisms, all of the same
species, that occupies a given area or ecosystem. (Allaby 1998)
population control
The ecological processes that limit
density.
population regulation
Limitations on the density of a
population that are imposed by density-dependent factors. (Allaby 1998)
pore space
The fraction of the soil that is occupied
by water and air.
positive feedback
A control mechanism where change in a
variable (e.g. population increase) sets off a mechanism to increase the
change. In a system, the mechanism by which a process intensifies or
accelerates, as each cycle of operation establishes conditions that favour a
repetition. Unless checked, positivefeedback may lead to loss of control within
thesystem and its eventual failure. (Allaby 1998)
potential evaporation
Maximum evaporation, measured by the
daily loss of water from a free water-surface or calculated from meteorological
variables assuming that the supply of water is not limiting.
potential evapotranspiration
As for potential evaporation.
predation
The interaction between species
populations in which one organism, the predator, obtains energy (as food) by
consuming, usually killing, another, the prey. Most typically, a predator is an
animal that catches, kills, and eats its prey; bur predation also includes
feeding by insectivorous plants and grazing interactions. (Allaby 1998)
predator
An animal that catches, kills, and eats
its prey. (Allaby 1998)
presaturation
A period before the carrying capacity is
reached.
presaturation dispersal
Dispersal of individuals before the
carrying capacity is reached.
primary forest species
Used here in relation to rainforest.
Species representative of shade-tolerant, mature successional stages (so-called
primary forest species) are often found forming long-lived seedling pools.
primary succession
Succession initiated on a newly-produced,
bared area such as is produced by the retreat of a glacier, by the flow of lava
or the deposition of ash from a volcano, or by the deposition of sediment
carried in a flood.
prokaryotic
Of organisms that lack a true nucleus,
and that lack organelles bounded by a membrane.
promiscuity
The mating strategy of an organism that
mates with many members of the other sex, but forms no bonds.
propagule
A dispersal unit; that part (vegetative
or sexual) of the plant or colonial animal from which a new unit regenerates.
proteaceous
Belonging to the plant family Proteaceae
(which includes banksias, grevilleas, hakeas, and many others).
proteoid
Refers to the roots of some members of
the family Proteaceae: clusters of finely-divided and highlybranched roots.
protist
A single-celled, eukaryotic organism that
may resemble an animal or a plant. (Allaby 1998)
protistan
With the characteristics of the Protista:
singlecelled organisms including unicellular algae, protozoans (animals), and
bacteria.
protists, Protista
One of the kingdoms in the five-kingdom classification
of living organisms. Includes unicellular algae, protozoans, and bacteria.
protozoans, Protozoa
Single-celled eukaryotic organisms-for
example, ciliates, heterotrophic flagellates, amoebae.
provincialism
The occurrence of species within
well-defined biogeographic areas or provinces.
pseudomyine
Australian endemic rodents of the genus Pseudomys
(pseudo-mice), incorporating a largenumber of species.
psittacine
A bird belonging to the parrot family.
psyllid
Insect of the family Psyllidae, which
contains many species that feed on plant products. Sometimes referred to as
‘plant-lice'.
pyric succession
The series of changes in composition and structure
of a community following a fire.
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Q
quadrat
The basic sampling unity for vegetation
surveys. The size of the quadrat depends largely on the vegetation that is
being assessed, and may range from 1 m2 for grasslands to hundred or thousands of
square metres for forests.
quantum
An amount of energy = hν, where h
= Planck's constant and ν is the frequency of the electromagnetic radiation.
The energy of one mol of quanta (or Einstein) = Nhν, where N = Avogadro's
number.
quantum requirement
The quantum requirement, R, is the
number of quanta required for the reduction of one mol ofCO2 to one-sixth of a
mol of C6H12O6.
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R
radiant energy
Energy entering a system as
electromagnetic radiation.
radiation
The emission of waves of electromagnetic radiation
(energy).
Ramsar Convention
A convention on wetlands of world
importance agreed by a forum of international governments whose delegates met
in the town of Ramsar, Iran, in 1971.
random sampling
Taking samples according to an arranged
protocol of random numbers.
raptors
A bird of prey of the order Falconidae.
ratite
A large, flightless bird (with ‘no keel
on its sternum'; Allaby 1998)
recognisable taxonomic units
Many species do not yet have scientific
names but can be delimited consistently as ‘morphospecies', or ‘recognisable
taxonomic units' (RTUs). This approach enables ecologically informative groups
such as ants to be used effectively in environmental assessment.
reflectance
The proportion of radiation of a given
wavelength incident on a surface (such as a leaf) that is reflected by the
surface.
refuge
A site, defined in space and time, within
which particular organisms are sheltered from the competitive effects of other
species. (Allaby 1998)
refugium (pl. refugia)
An isolated area where extensive changes,
most typically due to changing climate, have not occurred. Plants and animals
formerly characteristic of the region in general find a refuge from unfavourable
conditions in these areas. (Allaby 1998)
relative density
The number of organisms in two areas of
similar size.
Relict
Term describing organisms that have
survived while other, related species have become extinct.(Allaby 1998)
reproductive value
A measure that includes current and
expected survival and fecundity.
resource competition
An interaction in which organisms harm
one another by using shared resources such as food and space that are in short
supply.
resprouters
Plants that recover after major damage to
the crown (for example, by fire) by sprouting from roots (suckers),
lignotubers, or shoots (epicormic shoots).
rhizome
An underground stem, usually growing horizontally.
rhizosphere
The rhizosphere includes the root of a
plant, the fungal and microbial assemblage around the root, and the inorganic
and organic chemistry of this area, including exudations from the root, fungi, and
micro-organisms.
rill erosion
A pattern of erosion often occurring,
with sheet erosion, in recently cultivated soils following heavy rains,
identified as a series of channels or rills up to 30 cm deep.
riparian
Pertaining to the banks of a watercourse,
such as a creek, stream, or river.
riverine
On the banks of a river; riparian;
pertaining to a river system.
r-selection
r-selected species are ‘opportunists'; the intrinsic rate of
increase (r) is maximised so that when conditions are favourable; these
opportunist species can rapidly colonise the area. r-selection is
particularly advantageous in rapidly changing environments, such as in the
early stages of a succession. (Allaby 1998)
ruderal
Applied to a plant (such as a weed) that
colonises waste ground. (Allaby 1998)
ruminant
Mammals in the sub-order Pecora with no
upper incisors; includes goats, sheep, deer, cattle.
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S
salinity
Refers both to the process whereby land becomes
increasingly saline, and to a property of soil or water. Salt concentration in
surface or groundwater, expressed as mg L-1, can be measured by heating to
evaporate the water, or electrical
conductivity of the water can be measured
and reported in electrical conductivity (EC) units.
sample
A statistical term; a sub-set of a
defined population that is taken for measurement, analysis, and so on according
to a defined sampling protocol.
saturation
The situation where a population reaches
the carrying capacity, K.
saturation dispersal
The dispersal of individuals of a
population when the population reaches carrying capacity.
savanna
Grassland with scattered trees, found in
areas marked by a hot dry season.
scleromorphy
Of a plant, the characteristic of having
a hard leaf.
sclerophyll (adj. sclerophyllous)
Literally, hard leaf. Sclerophyllous
vegetation is composed of many evergreen species with hard, leathery, and often
small, leaves.
scramble competition
Competition or adverse interaction
resulting in all individuals obtaining a smaller share of the food or shelter
that is in short supply.
secondary forest species
Used here in relation to rainforest.
Shadeintolerant pioneer species that form soil seedbanks but not seedling
banks.
secondary production
The rate of production of energy or mass
by heterotrophs (cf. net primary production).
secondary succession
Succession initiated after some major
change on a previously vegetated surface. Examples of change are fire,
hurricane, insect attack, abandonment of land that has been used for grazing,
timber harvesting.
sedentary
Of individuals or populations, inhabiting
the same region through life; not migratory.
seed-bank
Seed held either in fruiting bodies of
plants, or in viable condition in the soil.
seeders
Plants that reproduce by sexual means,
resulting in the production of seeds.
semelparity
Animal reproduction strategy of
reproducing only once during a life-time. Allaby (1998) calls this ‘big bang
reproduction'.
senescent
Over-mature and deteriorating. For
example, a senescent forest might be defined as one in which losses of organic
matter by respiration (decay) exceed gains by photosynthesis.
sensible heat
The energy that causes a change in
temperature of soil, plant, or air; so-called because it can be sensed with a
thermometer.
sere (adj. seral)
The sequence of changes (seral stages) in
vegetation succession.
sesquioxide
Of soil, refers to oxides in which the
atomic ratio of oxygen to metal is 1.5 : 1, as in Fe2O3 and Al2O3.
sex ratio
The ratio of male to female (or vice
versa) in the population.
sexual reproduction
Reproduction in which half the genetic
material of the offspring comes from male parent gametes and half from female
parent gametes.
short-wave radiation
Short-wave (solar) radiation is that
within the wavelengths 0.3-3 μm.
sigmoidal growth curve
The S-shaped growth curve of a
population. Growth increases exponentially until the carrying capacity, K,
is approached.
skeletal
Of soils, dominated by stones and rocks.
soil organic matter
Compounds of carbon (excluding
carbonates) in a soil.
soil profile
The vertical section of a soil from the
surface through all of the horizons to the parent material.
solifluction
The downhill movement of the soil
profile, after it has become saturated with water.
solute potential
Solute potential (or osmotic potential)
is that component of water potential that is due to the presence of solutes.
Solutes decrease the concentration of water molecules, thereby lowering water
potential.
sonde
Balloon-borne instrument that makes in
situ measurements in the atmosphere.
specialist
A species that uses a narrow range of
resources (such as food and shelter).
speciation
The separation of populations (of plants
or animals) originally able to interbreed, into independent evolutionary units
that are no longer able to interbreed. (Allaby 1998)
species diversity
The variety of species on the Earth.
(Environment Australia 2002)
speciose
Consisting of a number of species.
sprouters
Plants that reproduce vegetatively by
shoots and suckers.
stable isotopes
Non-radioactive isotopes. Isotopes are
forms of an element that have the same chemical properties but that differ in
atomic weight (for example, 12C and 13C; 16O and 18O). Stable isotopes are important
tools in ecophysiological research.
stand
A place in a forest (thus a ‘stand of
trees').
static life table
A life table compiled from the age
structure of a population at a particular time.
Stefan-Boltzmann law
A law describing the relationship between
temperature and the radiation emitted by a black body. The total energy emitted
by a black bodyincreases in proportion to the fourth power of the absolute
temperature of the body.
stochastic
Variable, random; operating with a
probability.
strata
Layers in a plant community, such as ‘overstorey',
‘understorey', ‘shrub layer', and ‘ground layer'.
stratification
The separation of the waters of a lake or
ocean into distinct layers of different density that do not mix (or mix very
slowly).
stratosphere
The upper layer of the atmosphere, above
the troposphere.
stress
A physiological condition, usually
affecting behaviour, produced by excessive environmental or psychological
pressures. (Allaby 1998)
subalpine
Pertaining to the sparsely-timbered and
associated treeless zone immediately below the treeless alpine zone.
subgenus (pl. subgenera)
A group with characteristics that are
different from other groups within the genus, but not sufficiently different to
warrant classification as a new genus.
subhumid
Of a climate, within the range between
arid and humid.
succession
The sequence of changes in a community of
plants and/or animals.
surrogate
Something that acts for, or is a
substitute for, another thing. Surrogates are used as an aid to so-called
‘rapid biodiversity assessment'. Vegetation maps are the most frequently used surrogates
for biodiversity-that is, if some proportion of each mapped type of vegetation
is protected, it is assumed that populations of other organisms will also be
protected.
survival rate
The number of individuals in a given population
surviving over a defined period of time.
symbiosis
A general term describing the situation
in which dissimilar organisms live together in close association. (Allaby 1998)
sympatric
Of species, having ranges that overlap.
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T
taxon (pl. taxa)
A taxonomic group, whatever its rank.
tectonic
The study of the relative motion of
Earth's crustal blocks or plates.
tectonic plate
A major slab of the terrestrial
lithosphere, 100-150 km thick (Emiliani 1987). The crust of the Earth consists
of plates that are moving on the semi-liquid mantle (continental drift),
separating and colliding.
texture
The nature of a soil (sandy, loamy,
clayey), as sensed by the feel and behaviour of a wetted ball of soil. Texture
is determined both by the relative proportion of mineral particles and by the
content of organic matter.
thermoregulation
The regulation of body temperature.
therophytes
Annual plants. One of the life forms of
plantsproposed by the ecologist C Raunkiaer.
thickening (of vegetation)
An increase in mass of trees and shrubs,
seen in a number of countries and due to a number of causes. For example, the
reduction of surface grassy fuel loads by stock grazing and the selectiveness
of ruminant grazing (avoiding woody plants), together with the suppression of
fire, is leading to thickening of shrub and tree density in many areas of
Australia, Africa, and elsewhere.
time-specific life-table
The age structure of a population at a
particular time or time interval (for example, as given by census data for
human populations).
topography
Physical features of the landscape
surface, such as altitude, slope, and aspect.
trade-offs
A perceived compromise in the allocation of
limiting resources (food, water, shelter). For example, a trade-off may exist
between the allocation of resources to growth or to reproduction, or to
reproduction now or to reproduction in the future. Also used in interpretations
of evolution-for example, in the evolution of a plant species, there may be a trade-off
between shade tolerance and drought tolerance.
transects
Lines that are set out through vegetation
for the purpose of collecting data. Measurements of species' presence or
absence, cover, height etc are made at measured intervals (regular or random) along
the transect.
transpiration
The evaporation of water, transported
through the xylem from soil to leaf, from the leaf surface.
trophic
Adjective referring to the level in the
food chain.
troposphere
The lower layer of the atmosphere,
varying in height from about 10 km at the poles to about 17 km at the Equator.
tuber
A thick, fleshy underground stem that
functions as storage for water and carbohydrates, and is active in vegetative
reproduction.
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U
understorey
Denotes, generally for a forest, the
layer of vegetation that grows between the overstorey (the dominant trees) and
the shrub layer and/or the ground layer.
ungulate
Hoofed, grazing mammal-for example,
horse, zebra.
unitary organism
An organism in which each individual of
the species exists as an individual-that is, as a separate genetic unit.
univoltine
Applied to species in which one
generation reaches maturity each year. (Allaby 1998)
urbanisation
The progressive expansion of cities with
the associated destruction of habitat.
UV radiation
Ultraviolet radiation; radiation in the
wavelengths 5 nm-4 μm, or in general terms, radiation of wavelengths between
X-rays and visible light (that is, just shorter than violet light).
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V
vapour pressure deficit
For a given temperature, the difference
between the saturation vapour pressure of air (the maximum amount of water
vapour the air can hold at that temperature) and the actual vapour pressure.
The greater the vapour pressure deficit of the air, the greater the rate of
evaporation from a saturated surface in contact with the air.
vascular
A vascular system in plants is a
conducting system, consisting of phloem, xylem, and cambium, that is continuous
through all parts of the plant.
vascular plants
Plants possessing a vascular system
(xylem, phloem, and cambium) that is continuous through all parts of the plant.
vertebrates
Animals with backbones, members of the
phylum Vertebrata. The five classes of vertebrates are fish, amphibians,
reptiles, birds, and mammals.
vertosol
An order of soil in Isbell's (1996)
classification: clay soils with shrink-swell properties, cracking when dry.
Australia has the greatest area and diversity of cracking clays of any country
in the world.
vesicular-arbuscular mycorrhiza
An association between a fungus and the
roots of a plant where the fungus forms vesicles and arbuscules (organs for
storage of carbohydrate and nutrients) within the root tissue (the cortex).
videography
Remote sensing imagery in video format
obtained from a plane.
vine
Trailing or climbing plant.
vital attributes
A term used by Noble and Slatyer (1980)
in defining the course of succession. Vital attributes of a species include the
method of arrival or persistence, the ability to establish and grow to maturity, and the time to reach critical
life stages.
vivipary
Giving birth to live young. Some plants
(for example, mangroves) are viviparous in that the seed germinates within the
fruit, producing within the plant an established seedling that falls into the sediments.
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W
wallum
A word of Aboriginal origin used to
describe the heathlands of south-eastern coastal Queensland.
water potential
The chemical potential (Ψ)of water. The
water potential of pure water at the standard state is defined as 0 Pa
(pascal). Water potential is decreased by solutes (the concentration of water molecules
is decreased, so Ψ becomes increasingly negative), and increases with
temperature and pressure.
water use efficiency
For a vegetative community, the ratio of
dry matter gained to water lost by evapotranspiration, per unit area per unit
time; or in process terms, the ratio of the rate of photosynthesis to the rate of
transpiration. Often abbreviated as WUE.
water-table
The upper surface of groundwater, or the
level below which the soil is permanently saturated with water. (Allaby 1998).
Defined by the height to which water rises in an open well.
wavelength
The wavelength, λ, of electromagnetic
radiation is the distance between successive points of equal phase (for
example, the distance from one crest to the next).
weed
Quite simply, a plant growing in the
wrong place (a place where we do not want it to grow). A plant that is neither
desired nor appreciated in that place.
Wein's Displacement law
The maximum wavelength at which a black body
emits radiation (λmax, μm) = 2897/T where T is absolute temperature. This is
the basis for the ‘greenhouse effect'. The Sun has a surface temperature close
to 6000 K, so that λmax is close to 0.5 μm, towards the middle of the visible spectrum.
Carbon dioxide does not absorb radiation of that wavelength. The Earth has a surface
temperature close to 300 K, so that λmax is close to 10 μm, at which wavelength
carbon dioxide has a major absorption band.
whelks
Predatory gastropods with stout,
snail-like shells, common on many rocky shores. Prey include barnacles,
littorinids, and other marine snails. Important predators in marine habitats;
includes the muricids.
wilderness
Remote areas that remain substantially
undisturbed by the activities of colonial and modern technological society and
that are large enough to ensure the long-term protection and integrity of their
natural systems and biological diversity. (State of the Environment Advisory
Council 1996).
wilting point
The amount of water remaining in a soil
after the plant growing in the soil has wilted permanently (that is, it will
not recover).
woodland
Defined by Specht (1970) as a community
of trees with a projective foliage cover less than 30%.
World Heritage Area
An area deemed to have outstanding
universal value, and placed on UNESCO's World Heritage List. Examples in
Australia are the Great Barrier Reef (Queensland), Kakadu National Park (Northern
Territory), Tasmanian Wilderness World Heritage Area, and Australian Fossil Mammal
Sites (Riversleigh, Queensland, and Naracoorte, South Australia).
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X
xeromorphic
Of organisms, with morphological
adaptations that appear to be able to withstand drought.
Z
zooplankton
Aquatic animals
that drift with water movements, generally having limited locomotive organs.
They include protozoans, small crustaceans, and the larval stages of larger organisms.
(Allaby 1998)
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