Moving from species to ecosystems
Much of the debate on declining biodiversity has been framed around disappearing species. A new IUCN Red List promises to enlarge this debate to take ecosystems into account and CEED researchers have made several important contributions to its development. The status of threatened species is but one facet of the conservation problem of declining biodiversity. Scientists have become increasingly concerned about the ecosystems and their processes that support species, their interactions and environment. What we have long needed is a Red List of Ecosystems, and last year the IUCN (the International Union for the Conservation of Nature) delivered one.
It’s a risk assessment framework for ecosystems that lets the IUCN rank ecosystems as endangered, vulnerable or not threatened according to the risks they face. Defining, measuring and comparing ecosystems is a much tougher proposition than defining, measuring and comparing the status of threatened species (which is challenging enough in itself). It’s easy to observe that the Aral Sea is a collapsed ecosystem; the sea itself has largely disappeared and with it many of its native animals and plants – never to return. In terms of area, composition and function, this ecosystem is gone. But what about the Coorong wetland or the Great Barrier Reef? They’re under tremendous pressure but at what point should they be considered vulnerable as opposed to endangered? The Red List of Ecosystems assesses an ecosystem against multiple criteria: how rapidly is it declining and what is its current extent? How rapidly and how extensively are its physical and biological components degrading? And what is the nature of the multiple threats it faces and how are these threats interacting?
The ecosystems framework that has been released by the IUCN is the product of many discussions and workshops between scientists. CEED researchers Dr Emily Nicholson and Dr Tracey Regan spent 2012 and 2013 hosting workshops and collaborating with the IUCN, and state and federal conservation agencies to develop definitions and measurements of ecosystems and threat status. They were coauthors of the paper that described the new IUCN Red List criteria, and applied them to 20 illustrative case studies (Keith et al., 2013). Nicholson and Regan are part of a research team (funded by an ARC Linkage grant) to systematically test these criteria under a range of conditions. Of the ecosystems they compared, the remote mountain ecosystems of the Venezuelan Tepui are among those at least risk of collapse. These systems are showing little evidence of decline in distribution or function in the past or near future. At the other extreme is the Aral Sea, which collapsed during the 1980s and 1990s.
In May 2014, during the IUCN’s 83rd meeting in Switzerland, the categories and criteria for the identification of threatened ecosystems and the creation of Red Lists of Ecosystems were officially adopted. This marks the end of a long process that started back in 2007. The criteria are described in Keith et al., 2013. The criteria are currently being applied across the whole of the Americas, and have been used in over 40 countries. This includes a suite of assessments in Australia (to appear in a forthcoming issue of Austral Ecology). In terms of local influence, the Australian government has revised some of its criteria for assessing ecological communities to match those of the IUCN and South Australia is looking to use the criteria directly in setting up a list of threatened ecosystems/ecological communities there. The world now has a conservation tool that allows us to look beyond species to the ecosystems they are a part of.
Workshopping the criteria
In 2012, some 32 people from all around the world met at the School of Botany, University of Melbourne, at a CEED-sponsored workshop on the IUCN Red List of Ecosystems (see Decision Point #62). The focus of the workshop was on the application of the draft criteria to marine systems, definitions of collapse (analogous to extinction for species), and ways of assessing change in ecological function as they move towards collapse.
Note: See Emily Nicholson’s blog for more background on the IUCN Red List of Ecosystems with links to other papers and other information on this important new tool for conservation: http://emilynicholson.wordpress.com/
Keith DA, JP Rodríguez, KM Rodríguez-Clark, E Nicholson, et al. (2013). Scientific foundations for an IUCN Red List of Ecosystems. PLoS ONE, 8(5): e62111