Article Index

How we monitor biodiversity in jarrah forest managed for sustainable forestry

For each grid site:

  • record species richness and abundance
  • determine the species composition within each treatment
  • analyse trends in species richness, abundance and composition between treatments, as well as other characteristics specific to each group.

FORESTCHECK researchers use a variety of methods to monitor biodiversity.

Lichens, mosses and liverworts

 Method: Transects

  • Researchers walk along a fixed path, one metre wide and 200 metres long. The number and type of all species (known and unknown), and the habitat and host material preferred by each species, are recorded along three transects on each grid.
  • Fungi are plentiful, but only those that produce visible fruiting bodies late in autumn, following the winter rains, are recorded.

Many lichens, mosses and liverworts blend well into their surroundings, and seeing them requires a keen eye.

Transect line

Flowering plants

 Method: Plots

  • Researchers document plant species and their abundance within six 1,000- square- metre plots on each monitoring grid.
  • The amount of cover the plants provide and the physical structure of the understorey vegetation is also measured.



Invertebrates (including insects)

Methods: Light traps, pitfall traps, foliage beating
Insects, alone, are so numerous that it would take a disproportionate amount of time to identify them. FORESTCHECK researchers record only those larger than a centimetre unless they are a distinctive or targeted species.

  • Many insects are well hidden or only emerge at night, so recording species like the Dryandra moth (Carthaea saturnioides) requires capturing them using light traps. A large number of insect species are attracted to light. Most light traps use fluorescent bulbs to keep insects 'glued' to a surface until they can be collected.
  • Ground-dwelling insects such as crickets, and other invertebrates such as scorpions, are caught in small pitfall traps (containers buried in the ground).
    Insects fall into the traps and are unable to escape.
  • Branches are beaten and shaken to dislodge insects onto a large sheet or tarpaulin to collect species, such as weevils, that live in the foliage of understorey trees and shrubs.

We also record the presence of Gondwanan relics—species that have survived in the south-west from the time of the ancient Gondwanan forests over 100 million years ago.

Pest species, such as the pdfgum leaf skeletoniser which defoliates eucalypts, are also monitored.

Pitfall trap
Pitfall trap


A light trap captures Helena gum moths (Opodiphthera helena)

Birds (nocturnal and diurnal)

Methods: sight and sound, spotlight transects

Birds are identified during the day and at night.

Researchers look and listen for birds along a transect.

Boobook (Ninox boobook) and masked owls (Tyto novaehollandiae) have been recorded during night spotlight studies.

  • Birds are identified during the day and at night.
  • Researchers look and listen for birds along a transect.
  • Boobook (Ninox boobook) and masked owls (Tyto novaehollandiae) have been recorded during night spotlight studies.

Southern boobook (Ninox boobook)

Mammals (terrestrial mammals, nocturnal and diurnal)
Reptiles and frogs 

 Methods: wire traps and pit traps

  • Pitfall trapping is used for small mammals and reptiles.

    A smooth-sided bucket is dug into the ground and a low fence installed that leads to the pit trap. Reptiles and small animals run along this fence and fall into the pit trap. Others simply jump into it.

  • Specially designed wire cages are baited with a peanut butter and oat mixture to lure larger mammals into them. The cages have a treadle mechanism that releases the door and trap the unsuspecting mammals,such as echidnas, pygmy possums and dunnarts.  The numbers of mammals are very low in areas that have not been baited for foxes.

All captured mammals, reptiles and frogs are weighed, tagged (or temporarily marked) and then released.

All animal trapping is conducted under strict Australian Government animal ethics guidelines and regulated by Parks and Wildlife's animal ethics committee.


Pit Traps
Pit Traps

Wire traps
Wire traps

Forest attributes

Methods: Various

Physical attributes of the forest, such as leaf and soil nutrients, are assesed by chemical analysis.

The amount of coarse woody debris and litter in the forest is measured by plots and transects.

  • Litter is material less than six millimetres in diameter. This is measured with a defined circle using a metal cylinder
  • Small twigs are between seven and 25 millimetres in diameter, and is sampled within a small, defined plot
  • Coarse woody debris debris (snags, fallen logs, wind-blown trees and large branches greater than 2.5 centimetres in diameter) is measured along a defined transect. Decomposition of this material returns nutrients and carbon to the soil. Coarse woody debris provides nesting sites for forest animals and habitat for other organisms that are decomposers or form components of forest food webs.

Log extraction tracks and landings around the grids are mapped using GPS. The degree of soil disturbance and compaction due to forestry practices is then measured by soil core sampling.

Equipment for sampling litter and small twigs
Equipment for sampling litter and small twigs

Soil disturbance from harvesting machinery
Soil disturbance from harvesting machinery