Protecting biodiversity one task at a time: have your say

The fact that the Earth is in the midst of a biodiversity crisis has been repeatedly acknowledged by world governments. The greatest pronouncement was is 2002 with the '2010 Biodiversity Target' where many of the largest economies signed a pledge to halt biodiversity loss by 2010. Yet it is now 2010 and species are continuing to go extinct and habitats are continuing to be destroyed or degraded. But it shouldn't be a surprise that non-binding governmental proclamations fail to produce substantial results. Yet the reality is that we need to do something, inaction only worsens the legacy of biological deficit for future generations.

Maybe the best way forward is not more international governmental summits, but rather focusing on small scale, achievable short term goal. Guillaume Chapron started the Biodiversity 100 campaign, hosted by the Guardian (see story here), which seeks out public and professional input into the 100 immediate and achievable projects or ideas that will help protect biodiversity. The idea is to be able to go to governments and international agencies with this list and get them to make specific pledges to carry out these tasks.

There is till time to participate! If you have an idea of an action to protect biodiversity, fill out the web form. There are already a plethora of great suggestions, from protecting specific habitats to stemming population growth. This list is important because it includes the voices of the international public citizenry and that of scientists. More than that though, there will be a concrete list of tasks (ranging from very local to very global) that citizen groups can use to sustain pressure on governments.

Predicting endangered carnivores: the role of environment, space and phylogeny

For conservation biology, there are several research thrusts that are of critical importance, and one of these is to find predictors of species' extinction risk. Oft-cited is the particular susceptibility of large-bodied organisms, with their large ranges and slow reproductive rates. But there should be other predictors too, especially within larger mammals. In a forthcoming paper in Global Ecology and Biogeography, Safi and Pettorelli use just a few variables to predict extinction risk in carnivores.
They quantified species extinction risk according to the IUCN risk assessments and asked how well three attributes explained variation in extinction risk. They quantified the environmental characteristics of the species' ranges (temperature, precipitation, etc.), spatial distances between species' ranges and the phylogenetic distances among species. Overall, spatial and phylogenetic distances were good predictors of threat status -generally predicting between 21-70% of variation in extinction risk, whereas the environmental variables were weaker predictors. Full models incorporating all three variables (and accounting for their covariance), were able to explain upwards of 96% of the variation in extinction risk!

Although these variables do not represent causal mechanisms of extinction risk -rather they are correlative, they do provide conservation biologists with a rapid assessment tool to evaluate extinction risk. These tools should be particularly important in cases were population data are lacking and immediate pragmatic decisions are required.

Safi, K., & Pettorelli, N. (2010). Phylogenetic, spatial and environmental components of extinction risk in carnivores Global Ecology and Biogeography DOI: 10.1111/j.1466-8238.2010.00523.x

How can evolution inform conservation decisions?

First of all, let me apologize for the lack of blog posts over the past 2 weeks, I've been busy visiting the Olympics and reading a couple of hundred blogs, judging them for the Research Blogging awards.

The conservation of biological diversity is a major imperative for biologists. International agreements such as the Convention on Biological Diversity and intergovernmental exercises, such as the Millennium Ecosystem Assessment, call upon scientists to provide evidence on the current state of biological diversity and to evaluate solutions for reducing diversity and ecosystem function loss. Critical to these efforts have been the work of ecologists, conservation biologists and ecological economists. However, seemingly missing from the conversation about the state of biodiversity knowledge has been evolutionary biologists. Are they primarily concerned with describing historical processes and mechanisms of biological change, or do they have substantive knowledge and ideas that should be viewed as a critical component of any scheme to conserve biological diversity?

In a recent paper in Evolution, Hendry and a number of coauthors convincingly make the case that evolutionary biology is a necessary component for conservation. Evolution offer four key insights that should inform conservation and policy decisions. First, they point out that evolutionary biologists are in the business of discovering and documenting biodiversity. They are the primary drivers behind long-term, sustained biological collections, because they need to know what exists in order to better understand evolutionary history. With millions of species awaiting scientific discovery, their efforts are critical to measuring biodiversity. But not only are they discovering new species and enumerating them, they are uncovering their evolutionary relationships, which gives conservationists better information about which species to prioritize. What Vane-Wright famously called 'the agony of choice', with limited resources, we need to prioritize some species over others, and their evolutionary uniqueness ought to be a factor. More than this, evolutionary biologists have developed pragmatic tools for inventorying and sharing data on biodiversity at all levels, from genes to species, which is available for prioritization.

The second key insight is that by understanding the causes of diversification, we can better understand and predict diversity responses to environmental and climatic change. By understanding how key functional traits evolve, we can develop predictions about which species or groups of species can tolerate certain perturbations. Further, research into how and why certain evolutionary groups faced extinction can help us respond to the current extinction crisis. For example, the evolutionary correspondence between coevolved mutualists, such as plants and pollinators, can be used to assess the potential for cascading extinctions. These types of analyses can help identify those groups of related species, or those possessing some trait, which make species more susceptible to extinction.

Thirdly, evolution allows for an understanding of the potential responses to human disturbance. Evolutionary change is a critical part of ecological dynamics, and as environment change can result in reduced fitness, smaller population sizes and extinction, evolution offers an adaptive response to these negative impacts. Knowing when and how populations can evolve is crucial. Evolutionary change is a product of genetic variation, immigration, population size and stochasticity, and if the ability to evolve to environmental change is key for persistence, then these evolutionary processes are also key.

Finally, evolutionary patterns and processes have important implications for ecosystem services and economic and human well-being. Both genetic and evolutionary diversity of plant communities has been shown to affect arthropod diversity, primary productivity (including work by me) and nutrient dynamics. Thus understanding how changes in diversity affect ecosystem processes should consider evolutionary processes. Further, exotic species are often cited as one of the major threats to biodiversity, and evolutionary change in exotics has been shown to increase exotic impacts on native species.

All together, these key reasons why evolution matters for conservation, mean that developing sound management plans requires considering evolution patterns and processes. We can use evolution to our benefit only if we understand how evolution shapes current dynamics. The challenge to evolutionary biologists is the same as it was for ecologists perhaps 15 to 20 years ago, to present their understanding and conservation ideas to a broader audience and to engage policy makers. To this end, the authors highlight some recent advances in incorporating evolutionary views into existing biodiversity and conservation programmes –most notably into DIVERSITAS.

Just like ecological processes and dynamics cannot be fully understood without appreciating evolution ancestry or dynamics, developing an extensive, expansive conservation strategies must take into account evolution. I hope that this paper signals a new era of a synthesis between ecology and evolution, which produces precise, viable conservation strategies.

Hendry, A., Lohmann, L., Conti, E., Cracraft, J., Crandall, K., Faith, D., Häuser, C., Joly, C., Kogure, K., Larigauderie, A., Magallón, S., Moritz, C., Tillier, S., Zardoya, R., Prieur-Richard, A., Walther, B., Yahara, T., & Donoghue, M. (2010). EVOLUTIONARY BIOLOGY IN BIODIVERSITY SCIENCE, CONSERVATION, AND POLICY: A CALL TO ACTION Evolution DOI: 10.1111/j.1558-5646.2010.00947.x

Enrichment and diversity loss: a mechanism tested

To paraphrase Thomas Henry Huxley: How stupid of us not to have thought of that!

In what has to be one of the most elegant and simple experiments I've seen in a long time, Yann Hautier, Pascal Niklaus and Andy Hector tested a basic mechanism of why nutrient enrichment results in species loss. This is a critically important issue as it has been repeatedly shown that while adding nitrogen to plant communities causes increases in productivity, species go locally extinct. We may bare witness to local diversity declines because human activity has greatly increased nutrient deposition. This pattern has been observed for a couple of decades, but the exact mechanism has never been adequately tested, with some camps believing that enrichment increases below-ground competition for other resources that become limiting, or above ground for light.

As reveled in the most recent issue of Science, Hautier et al. performed an exceedingly simple experiment; they added light to the understory of plant communities with or without nitrogen additions. They made two compelling observations. First, when communities were enriched without elevated light, they lost about 3 of the 6 initial species compared to the control, while light addition in the enriched communities maintained the 6 member community (as did a light only treatment). The second result was that the light plus nitrogen treatment obtained much higher biomass than either the nitrogen or light only treatments, and in fact the light only treatment did not significantly increase productivity, meaning that the communities are not normally light-limited. Further, they failed to detect any elevated belowground competition for other resources.

These results reveal that nutrient enrichment causes diversity loss because increased plant size increases light competition and plants that grow taller with elevated nitrogen are better light competitors. An old problem solved with the right experiment.

Hautier, Y., Niklaus, P., & Hector, A. (2009). Competition for Light Causes Plant Biodiversity Loss After Eutrophication Science, 324 (5927), 636-638 DOI: 10.1126/science.1169640

Conserve now or wait for the data?

E. O. Wilson, referring to the ethical imperative we should apply to the conservation of life, said “The ethical imperative should be, first of all, prudence. We should judge every scrap of biodiversity as priceless while we learn to use it and to come to understand what it means to humanity” (pg. 351, The Diversity of Life). Although, I would argue we should aim to learn biodiversity’s value, both intrinsic and extrinsic, as opposed to what it solely means to humanity, his point is protect now, study later. The reason being that there is still so much to learn in order to adequately assess the Earth’s biological riches, by the time we inventory and map a fraction of biodiversity, we would have lost numerous unique regions and species. Of course the opposing point of view is that we need detailed information in order to best use limited resources to best protect biodiversity. This is a major philosophical divide. In a recent, important paper by Hedley Grantham and colleagues published in Ecology Letters, the question of how long should we wait to take conservation actions was empirically tested.

The authors used simulations based on 20 years of habitat loss data from the biologically-rich Fynbos region of South Africa and knowledge about spatial distribution of Protea diversity. Protea surveys (The Protea Atlas) have been carried out over 20 years, inventorying 40,000 plots and recording 381 species within the Proteaceae. They began their simulations with no information about Protea diversity patterns and included annually increasing knowledge, set against annual habitat destruction. They showed that waiting to make conservation decisions after only 2 years resulted in species loss, because habitat loss far outweighed any advantage to gaining more information. Further, more detailed information did not appear to increase the effectiveness of conservation decisions over cruder habitat-level maps.

The philosophical divide between protect now-learn later versus the need for detailed information to maximize resources appears bridgeable. It seems that by just accumulating some rough data may go a long way towards making those important conservation decisions. Of course, the irony is that this study needed 20 years of data to adequately assess this.

Grantham, H., Wilson, K., Moilanen, A., Rebelo, T., & Possingham, H. (2009). Delaying conservation actions for improved knowledge: how long should we wait? Ecology Letters, 12 (4), 293-301 DOI: 10.1111/j.1461-0248.2009.01287.x

Salamaders and climate change -impending extinctions?

By the now the evidence of a global frog decline, perhaps even an extinction crisis, has been well documented. But what about salamanders? They are normally less abundant and less-studied compared to frogs, but is there evidence of the same general pattern of declining population sizes? According to Sean Rovito and colleagues, the answer is unfortunately yes. They repeated a plethodontid (lungless) salamander survey done in the 1970’s in Central America and found that many species have declined. In fact they failed to find a couple of previously very abundant species. They also found that species declines were phylogenetically non-random and so these declines may result in the loss of whole clades of species, meaning that the evolutionary history of these salamanders is at risk.

The authors attempted to determine the cause of these declines and found that neither habitat loss or the chytridiomycosis fungal disease implicated in other declines explained these salamander declines. The authors hypothesize that these declines are a direct result of climate change –namely changing temperature and humidity. If so, we may be witnessing some of the first extinctions that are directly caused by climate change.

S. M. Rovito, G. Parra-Olea, C. R. Vasquez-Almazan, T. J. Papenfuss, D. B. Wake (2009). Dramatic declines in neotropical salamander populations are an important part of the global amphibian crisis Proceedings of the National Academy of Sciences, 106 (9), 3231-3236 DOI: 10.1073/pnas.0813051106

Post script:
We had a comment questioning the use of climate change as an explanation and here is my response.

Science works by finding parsimonious explanations, until through experimentation or observation another, better explanation emerges. The previous explanations of habitat loss or fungal infections were not supported. These habitats, known as cloud forests, are very humid. The lungless salamanders have no lungs and instead breath through their skin, which must be kept moist. These forest are becoming drier, hence the probable connection. Here's a quote from the paper:

"Pounds et al. (25) used modeling to show that largescale warming led to a greater decrease in relative humidity at Monteverde compared to that caused by deforestation. Species of cloud forest salamanders that can still be found rely at least
in part on bromeliads. Bromeliads depend on cloud water deposition and are predicted to be articularly vulnerable to climate change (26, 27)."

Doesn't sound like "magic" to me, rather a robust hypothesized mechanism worthy of more testing. Given that species are going extinct, it is important to suggest likely mechanisms, providing an impetus for more research.

For those that think that scientists use climate change as boogey man to scare up more research funding (i.e., Crichton), please read the science. You'll discover honest, hardworking folks that are trying to understand this changing world and whose research can only benefit you , me and the salamanders.

Local extinctions reveal metacommunity dynamics.

Metacommunity dynamics (i.e., that dispersal limitation among locales creates spatially-contingent community processes) have been in vogue over the past half-decade. Many of the advances in this field have come from theoretical models, computer simulations, artificial laboratory assemblages of micro-organisms (with yours truly being a major offender) and field experiments using small-bodied, short-lived organisms. An oft-repeated criticism has been that the necessary conditions for metacommunity processes are what are manipulated in simulations or lab tests and that simple extinction-colonization dynamics are rarely observed for larger, longer-lived organisms. In a recent paper by Kevin Burns and Christopher Neufeld, high levels of extinction and colonization are shown in patchy communities of woody plants. They sampled 18 islands off the west coast of Canada in 1997 then again in 2007 and found that substantial numbers of local extinctions were observed. These results reveal that what we often think of as relatively stable communities (woody plant species) are actually quite dynamic, creating the conditions were metacommunity processes are an important mechanisms driving patterns of diversity. They further show that communities with greater exposure to ocean storms had higher extinction risk and species with hardier leaves were less prone to local extinctions.

Kevin C. Burns, Christopher J. Neufeld (2009). Plant extinction dynamics in an insular metacommunity Oikos, 118 (2), 191-198 DOI: 10.1111/j.1600-0706.2008.16816.x