Protecting endangered species hotspots is touted as a simple, efficient way of conserving as many at-risk plants and animals as possible. But this approach may not be enough to protect endangered species because today's hotspots may not be tomorrow's hotspots, according to new research in the April issue of Conservation Biology
This is the first study of how the location and relative importance of hotspots changes over time.
"Hotspots serve as a useful tool for guiding conservation efforts but...do not represent a final solution," say Daniel Rutledge, who did this work at Michigan State University in East Lansing, Michigan, and is now at Landcare Research in Hamilton, New Zealand, and his three co-authors.
To see if hotspots of threatened and endangered species change with time, the researchers assessed the distribution of U.S.-listed species by county. Based primarily on the number of listed species, the reseachers determined which counties were hotspots during three overlapping time periods: 1967-1979, 1967-1989 and 1967-1999. The researchers then ranked the hotspots according to the number of unique listed species.
Rutledge and his colleagues found that the number of hotspots required to protect all the listed species rose from 84 in 1979, to 166 in 1989, to 217 in 1999. This is hardly surprising -- the number of listed species increased from 227 to 1078 during this time period.
However, the researchers also found that both the location and importance of hotspots varied considerably through the years. Many counties were added to or removed from the hotspot list, and only 63 were hotspots during all three time periods. The relative importance of hotspots also varied considerably: the most striking examples are Highlands county, Florida, which went from not being a hotspot in 1989 to being ranked second in 1999; and Hancock county, Tennessee, which went from being ranked fifth in 1989 to not being a hotspot at all in 1999.
This work may also apply to biodiversity hotspots. "Biodiversity hotspots could change because knowledge about biodiversity and threats to biodiversity also change over time and across space," says Jack Lui, one of Rutledge's co- authors. However, the researchers stress that protecting hotspots is still important. "Any efforts to protect species and their habitats, such as the Critical Ecosystem Partnership [to protect 25 biodiversity hotspots worldwide], are a good thing," says Rutledge.
Rutledge's co-authors are: Christopher Lepczyk, Jialong Xie and Jianguo Liu, all of Michigan State University in East Lansing, Michigan.
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