There are many scientific papers and news reports currently that state that biodiversity is in rapid decline on Earth. No evidence is usually cited for this statement – it is considered to be self evident. What follows from that is typically a panic request for more work on declining populations, more money for conservation NGOs and national parks. Political ecology statements that request more money for ecological research are certainly on the right track if we are to understand how to achieve conservation of our biota. But the question I want to raise here is how to proceed on this broad issue in a logical manner. To do this I will not discuss political ecology or how to gain more donors for conservation agencies, valuable services to be sure. But behind all this advertising is a scientific agenda which needs careful consideration.
Problem #1 is to determine if there is a problem. In some areas of conservation ecology there is much agreement on principles – we all agree that we are losing natural areas for urban and agricultural development, that we need more protected areas, that most protected areas are not large enough, that there are serious problems with poaching of wildlife and lumber in some protected areas, and that global pollution is affecting much of our biodiversity. In other areas of conservation ecology there is much controversy about details. Is global biodiversity in rapid decline (Vellend et al. 2017, Cardinale et al. 2018)? How can we best identify species at risk, and once we identify them, what can we do to prevent population collapse?
The answer to Problem #1 is that there are problems in some areas but not in others, in some taxonomic groups, but not in others, but overall the data are completely inadequate for a clear statement that overall biodiversity is in global decline (Dornelas et al. 2019). The problems of biodiversity conservation are local and group specific, which leads us to Problem #2.
Problem # 2 is to go back to the ecological details, concentrating on local and specific problems, exactly what should we do, and what can we do? The problems here relate almost entirely to ecological methods – how do we estimate species abundances particularly for rare species? How do we deal with year to year changes in communities? How long should a monitoring program continue until it has reliable conclusions about biodiversity change? None of these questions are simple to answer and require much discussion which is currently under way. How long is a long-term study? It might be something like 30 generations for vertebrate species or even longer, but what is it for earthworms or bark beetles? How can we best sample the variety of insects in an ecosystem in which they might be in decline (Habel et al. 2019)?
We need to scale our conservation studies for particular species, and this has led us into the Species-At-Risk dilemma. We can gather data for a specific geographical area like Canada on the species that we deem at risk. Typically, these are vertebrates, and we ignore the insects, microbes, and the rest of the community. We try to identify threatening processes for each species and write a detailed report (Bird and Hodges 2017). The action plan specified can rarely be carried out because it is multi-year and expensive, so the matter rests. For many of these species at risk and for almost all that are ignored the central problem is action – what could you do about a declining species-at-risk, given funds and person-power? We do what we can on a local scale on the principle that it is better to do something than nothing (Westwood et al. 2019). But too often even if we have a good ecological understanding of declines, for example in mountain caribou in Canada, little or nothing is done (Palm et al. 2020). Conservation collides with economics.
I will try to draw a few possible conclusions out of this general discussion.
- It is far from clear that global biodiversity is declining rapidly.
- On a local level we can do careful evaluations for some species at risk and take possible action if funding is available.
- Setting aside large areas of habitat is currently the best immediate conservation strategy. Managing land use is critical.
- Designing strong monitoring programs is essential to discover population and community trends so that, if action can be taken, it is not too late.
- Climate change will have profound biodiversity effects in the long run, and conservation scientists must work short-term but plan long-term.
As we take actions for conservation, we ought to keep in mind the central question: What will this ecosystem look like in 100 or 200 years? Perhaps that could be a t-shirt slogan.
Bird, S.C., and Hodges, K.E. (2017). Critical habitat designation for Canadian listed species: Slow, biased, and incomplete. Environmental Science & Policy 71, 1-8. doi: 10.1016/j.envsci.2017.01.007.
Cardinale, B.J., Gonzalez, A., Allington, G.R.H., and Loreau, M. (2018). Is local biodiversity declining or not? A summary of the debate over analysis of species richness time trends. Biological Conservation 219, 175-183. doi: 10.1016/j.biocon.2017.12.021.
Dornelas, M., Gotelli, N.J., Shimadzu, H., Moyes, F., Magurran, A.E., and McGill, B.J. (2019). A balance of winners and losers in the Anthropocene. Ecology Letters 22, 847-854. doi: 10.1111/ele.13242.
Habel, J.C., Samways, M.J., and Schmitt, T. (2019). Mitigating the precipitous decline of terrestrial European insects: Requirements for a new strategy. Biodiversity and Conservation 28, 1343-1360. doi: 10.1007/s10531-019-01741-8.
Palm, E.C., Fluker, S., Nesbitt, H.K., Jacob, A.L., and Hebblewhite, M. (2020). The long road to protecting critical habitat for species at risk: The case of southern mountain woodland caribou. Conservation Science and Practice 2 (7). doi: 10.1111/csp2.219.
Vellend, M., Dornelas, M., Baeten, L., Beauséjour, R., Brown, C.D., De Frenne, P., Elmendorf, S.C., et. al. (2017). Estimates of local biodiversity change over time stand up to scrutiny. Ecology 98, 583-590. doi: 10.1002/ecy.1660.
Westwood, A.R., Otto, S.P., Mooers, A., Darimont, C., Hodges, K.E., Johnson, C., Starzomski, B. et al. (2019). Protecting biodiversity in British Columbia: Recommendations for developing species at risk legislation. FACETS 4, 136-160. doi: 10.1139/facets-2018-0042.