Glossary

achene

a dry, indehiscent, one-seeded fruit

adventitious

describing organs that arise in unexpected positions, such as roots growing from a leaf or buds growing from the stem

anthropogenic

caused by or attributed to human effects and activities; in particular, applied to landscapes resulting from human activities

apical meristem

the meristem (a region containing actively dividing or potentially actively dividing cells) at the tip of a stem or root that gives rise to primary tissues and is responsible for increase in length rather than girth of the axis

arboreal

pertaining to trees; living in or among trees; adapted for living and moving about in trees

bimodal

having two peaks of frequency or occurrence, with a trough in-between

biodiversity

the totality of life forms.  May be used at different scales and levels, such as community, species and genetic.  Includes diversity of forms at all levels

biogeography

the study of distribution patterns of living organisms and their patterns of global evolution and development

biomass

the quantity of living matter contributed to a given area or habitat by one or several kinds of organism, usually expressed as weight per unit area or volume

biome

a large, well-defined biological community having a particular form of vegetation and associated animals, e.g. desert, savanna, rainforest

brevideciduous

deciduous trees shed all their leaves at a certain season, e.g. before the winter or dry season. Brevi - or partly deciduous trees lose their leaves during at least one season during the year but never lose more than 50% of full canopy. Semideciduous trees lose more than 50% of their canopy for at least one period during the year. Evergreen species retain full canopy throughout the year.

butte

a butte is an isolated hill or mountain rising abruptly from the surrounding land.

C3/C4 photosynthetic pathways

photosynthesis is the sequence of reactions in which light energy from the sun is converted into chemical energy and used to produce carbohydrates and ultimately all of the materials of the plant. C3 plants produce, as the first step in photosynthesis, phosphoglyceric acid, which contains 3 carbon atoms. Most plants of temperate regions are C3 plants. They exhibit photorespiration (respiration in the light) thought to be a wasteful process for the plant hence they generally have lower CO2 fixation rates than C4 plants. C4 plants produce a 4 carbon compound, oxaloacetic acid, which contains 4 carbon atoms. C4 plants produce more glucose for a given leaf area than C3 plants hence grow more quickly. They can also continue to photosynthesize at high light intensities and low CO2 concentrations, and, most significantly, do not exhibit photorespiration hence C4 plants are favoured in hot environments with high solar radiation loads. Almost all tropical grasses in Australian savannas are C4.                                                                                                

Cenozoic Era

The time span between 66.4 million years ago to the present

calcareous soils

soils containing a substantial proportion of calcium carbonate

cambium

layer of actively dividing cells (a meristem) lying between the xylem and phloem - the vascular or transport tissue of the plant. The cambium forms additional xylem and phloem elements in a process known as secondary thickening.

caryopsis

the fruit typical of a grass.  An achene with the pericarp fused with the seed.

caulescent

having an obvious stem rising above the ground

cellulase

hydrolytic enzyme found in bacteria and some seedlings that breaks down cellulose (eventually broken down to its component glucose units). Cellulase, produced by bacteria living in the gut of ruminant animals, enables such animals to derive nutrients from the fibrous component of their diet.

cellulose

A polysaccharide composed solely of glucose units linked by b(1-4) glycosidic bonds. It is the most abundant cell wall and structural polysaccharide in the plant kingdom and probably the most abundant of all compounds found in living organisms.

community

Ecological term for any naturally occurring group of different organisms inhabiting a common environment, interacting with each other especially through food relationships, and relatively independent of other groups. Communities may be of varying sizes, and larger ones may contain smaller ones.

couline

of leaves, growing from the stem

dasyurids

A dasyure is a member of the group of carnivorous Australian mammals comprising the native cats and the Tasmanian devil.

Disturbance

A change in the structure of a system which usually affects its functioning.  Disturbances are often caused by a periodic events, such as floods, particularly severe storms, prolonged droughts, excessive herbivory, or activities such as bush-clearing and cultivation

ecological segregation

cf. niche

ecosystem

the physical environment and the community of organisms in a given area

edaphic

pertaining to the soil; due to soil or topography rather than climate

endemic

confined to a given region, e.g. an island or country; native to a country or locality; continuously occurring in a particular area.

endemism

the state of being naturally restricted a specified region

epicormic buds

buds that lie dormant under the bark of some trees, such as eucalypts, and grow when the tree is defoliated

epiphyte

a plant nutritionally independent but completely dependent on another plant for mechanical support  

equilibrium

a stable condition: a system in which no further net change is occurring.

eutrophic

(Of lakes) highly productive in terms of organic matter formed, well-supplied with nutrients. Eutrophication is the process whereby a body of fresh water becomes enriched with nutrients, increases in productivity, and accumulates organic debris.

fatty acids

long hydrocarbon chain with a -COOH group; fatty acids are components of fats, oils, phospholipids, and waxes.

fecundity

the reproductive output of an individual or species, expressed as the number of propagules produced

floristic

Floristics is the study of composition of vegetation in terms of the species (flora) present in it, i.e. it is a list of plants of an area

Folivores (or browsers)

Animals that eat the leaves of shrubs and trees

frugivorous

fruit-eating (same as fructivorous)

glabrous

describing a surface that is devoid of hairs or other projections

grazers

Animals that feed predominantly on grasses and forbs

herbivory

the consumption of living plant material by organisms other than pathogens

heterogenous

composed of parts of dissimilar kinds

igneous rock

A rock that has crystallized from a molten state

indigenous

originating in and characterising a particular region or country; native (to); inherent; innate

internode

In plants, the region of the stem between two successive nodes. A node is the position on the stem where the vascular tissue branches into leaves and other appendages.

invertebrate

animals without backbones

lifeform

of an organism, the visible expression of adaptive features, e.g. of habit, and perennation. Raunkiaer (1934) described lifeform as position with respect to the ground surface of the perennating bud on the plant.

litter

the uppermost layer of organic debris on the soil surface; essentially the freshly fallen or slightly decomposed vegetal material

mark-recapture

capture and mark of individuals from a population. If they are not marked then only relative abundance is measured. Mark-recapture is used to determine the absolute abundance of a population. Absolute abundance is needed, for example, to manage pest species and employ sustainable harvest techniques.

megapod

having large feet

mesas

a mesa is a land form having a relatively flat top and bounded wholly or in part with steep rock walls, common in arid and semi-arid parts of the south-west US and also in areas of inland Australia

metabolic biomass

this is the living tissue biomass, i.e. that which is respiring. In trees this refers to the outer layers as the inner sections are the dead wood (which is really non-functional, or dead, xylem). Xylem is the water-carrying tissue of plants.

metamorphic rock

A rock changed from its original form and/or composition by heat, pressure, or chemically active fluids, or some combination of them

mixed feeders

herbivores that may be both grazers and browsers

morphological

morphology is the study of form or structure

neotropical

belonging to that part of the New World extending from the tropic of Cancer southwards

niche

Often defined as "the role played by a particular species in its environment". Among the first to use the term ‘niche’ was Grinnell (1917,1924,1928), who viewed it as the ultimate distributional unit, thus stressing the spatial concept of the niche. Elton (1927) emphasised more ethological (behavioural) aspects, and defined the ecological niche as the functional role and position of the organism in its community, stressing especially its trophic relationships with other species. The idea of niche gradually became linked with competition and resource utilisation. The competitive exclusion principle says that no two species can occupy the same niche. Questions to ask are: 'How similar can competing species be, yet stably persist together?' 'What are the limits to niche overlap, the limits to similarity, among co-existing competitors? 

Osmotic adjustment

Osmotic adjustment involves the accumulation of organic solutes, and this allows plants to maintain positive turgor at low (negative) water potentials.

pedological

pedology refers to the more fundamental aspects of soil science, particularly the genesis and classification of soils

perennial

a plant that lives for more than one year and produces flowers on more than one occasion

phenology

a phase of ecology concerned with the correlation of climatic factors with reproductive and vegetative development

physiognomy

of vegetation, the general appearance without reference to composition, e.g. the mallee, mulga, woodland, sclerophyll forest communities

physiographic units

description of the structural and functional characteristics (physical features) of a landscape or geographic region.  A physiographic factor is any of the factors, apart from edaphic (soil), climatic or biotic, that affect the prevailing conditions within a habitat and the distribution of the plants and animals. Such factors include the topography of the area, altitude, drainage conditions, degree of erosion, slope of the land, etc. 

phytophagous

plant-eating

Plant quality (as food for organisms)

the ratio of assimilable plant matter (mainly protein-based compounds and soluble carbohydrates) to the amounts of unusable and inhibitory material (mainly fibre, lignin and secondary compounds), rather than as the absolute amount of crude protein and soluble carbohydrate present in a plant.

propagules

unit of vegetative reproduction, as a leaf or stem cutting, spore, seed

recruitment

the numbers of individuals added to a population between two census periods or generations

Resilience

A resilient system is usually not stable and the values of its state variables often change considerably when subjected to outside pressure (Walker 1980).  More importantly, the parameters of the system which influence its dynamics also change, thereby redefining the boundaries within which the system remains attracted to its equilibrium point.  As a result, future disturbances of the same type are more easily accommodated.  In contrast, in a stable system, the parameters of the system do not change with disturbance.

Resilience and stability should be defined in respect of the type of disturbance. Resilience to fire or flooding does not imply resilience to grazing. In general, systems are more resilient to disturbances that are a ‘normal’ feature of the ecosystem that they are to disturbances that are ‘unfamiliar’ in evolutionary terms. For example, Australian savanna vegetation is adapted to fire, but its native grasses and soils have not evolved with hard-hoofed herbivores and consequently some ecosystems have little resistance or resilience to grazing by livestock. The degree and frequency of disturbance is also important. For example, a system may be stable when grazing pressure is low to moderate, but heavy grazing pressure may exceed the resistance of the system to change: herbaceous biomass may be reduced to such a level that it no longer effectively prevents the establishment of woody plants. Therefore the disturbance results in the grassland changing into a woodland.

respiration

respiration can be divided into two types (i) external respiration - taking oxygen from the environment and giving off carbon dioxide (CO2), and (ii) internal, tissue or cell respiration - the chemical reactions from which an organism derives energy.

rhizome

in vascular plants, a usually more or less horizontal, often underground, stem; may be enlarged for storage; or may function in vegetative reproduction (nonsexual reproduction)

saxicoline

living or growing among rocks

scleromorphic

hardened outer surface

sedimentary rock

Rock formed from the accumulation of sediment, which may consist of fragments and mineral grains of varying sizes from pre-existing rocks, remains or products of animals and plants, the products of chemical action, or mixtures of these

Seed predators

consume seeds either before or after dispersal

senescence

the process of ageing; physiological decline

species abundance

relative abundance is the number of individuals of a species as a proportion of the total number of individuals

Soil Structure

The behaviour of soil is also influenced by its structure, or the way in which soil particles are grouped together in aggregate form. Massive soil is transformed into a structured, or aggregated, state by the wedging action of plant roots or ice and from the cracking of the soil at frequent intervals as it shrinks on drying

species composition

refers to the contribution of each plant species to the vegetation, or animal species to the area. Generally expressed as a percentage, so that all components add up to 100%.

species diversity

the evenness of the community, i.e. some single number to distinguish between a community with 30 equally abundant species and that with one common species and 29 rare ones.

species richness

total number of species present

Stability

A stable system is one in which those variables defining the state of the system (eg. species composition, relative abundances, biomass, or production) change little in response to outside pressures such as drought, fire or grazing.  If disturbed, they return rapidly to their original values (Walker, 1980).  A stable system therefore shows little variability through time in the amounts of its state variable.  The distinction between compositional stability (relative constancy of species composition and abundance) and functional stability (relative constancy of the processes maintaining primary production) needs to be emphasized since the two can be negatively correlated. 

stochastic

based on one item in the probability distribution of an ordered set of observations; conjectural

stratification

horizontal (spatial distribution) and vertical (height) layering of vegetation components

Stress

In the physiological sense is a constraining environmental influence that restricts the productivity and efficiency of an individual and, by extension, the ecosystem.  Such stresses usually operate when an environmental variable, such as temperature, light, water, nutrients or defoliation, deviates markedly from its normal range of values in the system.  Stress is seldom accompanied by mortality.  As stress becomes more severe it may cause a disturbance.

subterranean

existing, situated or operating below the earth’s surface; underground

symbiont

an organism which lives in close association with two or more dissimilar organisms; includes parasites (in which the association is harmful to one of the organisms), commensalism (in which it is beneficial to one, of no significance to the other), and mutualism (association is advantageous to both).

Tertiary Period

The earliest Period of the Cenozoic Era, beginning about 66.4 million years ago and ending 1.6 million years ago

translocation

the transport of materials within the plant. Minerals are translocated in the xylem and synthesised organic compounds, sugars, nitrogenous compounds, and some inorganic ions are translocated in the phloem.

ungulate

hoofed mammal

vertebrate

an animal having a backbone made of bony segments called vertebrae

Water use efficiency

Water use efficiency is the ratio of carbon uptake to transpirational water loss