Why Invertebrates?

Terrestrial Invertebrates

Terrestrial invertebrates make up over 95 percent of the different species of animals alive today on the world’s landmasses; in some habitats they can make up over 70 percent of animal biomass. They occupy almost all possible habitats and niches and are involved in driving or regulating most ecosystem functions and processes. Despite this, they tend to be left out of current environmental assessments, with regulators and practitioners being more concerned with the ‘charismatic megafauna’; the birds, mammals and other vertebrates.

This omission from the environmental agenda is as perplexing, as it is unjustified. Take minesite rehabilitation as an example. Without an adequate component of soil and litter invertebrates, such as termites, ants, worms and springtails, the soil would not develop an appropriate structure for healthy plant growth and valuable nutrients would not be cycled back to the soil. Without ants and pollinating flies and wasps, seeds would not be dispersed and many flowers would not be pollinated, meaning that populations of plants that have been so expensively established in the new rehabilitation would not be able to reproduce. Many of the vertebrate animals that we are so concerned with depend in part, or in whole on invertebrates for their diet. If their numbers are to be sustained, the invertebrates on which they depend must be present in adequate quantities. This brief and incomplete list of invertebrate roles surely indicates that this important component of the biota must be considered in rehabilitation and other aspects of environmental management.

One important aspect of environmental assessment is measuring environmental quality or success with rehabilitation. The introduction of Completion Criteria for rehabilitated mines is a graphic example of this. Such criteria tend to be generic and include measures such as percentage plant cover, number of plant species in quadrats or the presence of particular vertebrate habitats. A recent study by two PhD students compared the cost and environmental information gained by measuring plants, birds, and specific groups of invertebrates (e.g., ants, beetles, spiders, etc) as indicators of progress with minesite rehabilitation. The study convincingly showed that not only were invertebrates cost effective to survey, they provided a more faithful indication of the condition of the environment than surveys of vertebrate animals. This work can be found at the following link:

http://www.myrmecologicalnews.org/cms/index.php?option=com_content&view=category&id=50:myrmecol-news-10-69-76 (external website)

Happily, the situation is improving. A recent analysis all papers published in the journal Restoration Ecology between 1994-2008 indicated that increased attention is being paid to this component of the biota. Although much of this work is for monitoring, a growing number of studies relate to the economic or ecological value of animals in restored land. There is still a bias towards vertebrates over invertebrates, although the proportion of invertebrate-focused papers is steadily increasing. Analysis of these papers suggests that greater synergy would be obtained if standardised protocols had been used and, in the case of invertebrates, studies would be more informative if species-level identifications had been obtained. Partnerships with industry should allow long-term studies to be performed, which would provide more reliable information than that yielded from chronosequence-type investigations. This article can be found at:
http://onlinelibrary.wiley.com/enhanced/doi/10.1111/j.1526-100X.2009.00528.x/ (external website)

One area in which invertebrates are routinely considered is the surveying for short-range endemic animals, particularly the subterranean troglofauna and stygofauna. Short-range endemic invertebrates, by their very nature, can be threatened if an impending development overlaps their range. Since their extinction would be unacceptable under State and Federal legislation, surveys for their presence are often required before approval for a project can be granted. Annually, millions of dollars are being spent in Western Australia on surveys for SRE’s. By contrast, funds for research on non-SRE terrestrial invertebrates, which probably represent around 98% of animal species, are extremely sparse – a puzzleing anomaly! A full discussion of this issue can be found at:

http://onlinelibrary.wiley.com/doi/10.1111/j.1440-6055.2009.00715.x/full (external website)

Biomonitoring International has been formed in order to service the needs of clients who need to consider invertebrates. The directors, Professor Jonathan and Dr Mazé Majer are both entomologists with over 60 years of experience between them, having worked in South America and Africa, as well as throughout Australia. The company has a well-equipped entomology laboratory and undertakes consultancies in the areas of survey design, baseline surveys, monitoring of restoration progress, monitoring of habitat quality, surveillance of introduced species, taxonomic services, pest problems, expert opinions and desktop studies.

Read about our Baseline Surveys