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May

21

2008
 
 

Better aliens



Mammals are more effective invasive species than birds, study finds kill the pig!According to the “tens rule”, roughly ten percent of introduced species become established and ten percent of those become invasive. Only it doesn't hold for mammals or birds, according to Jonathan Jeschke's study, the findings of which are published in Diversity and Distributions. The Ludwig-Maximilians-University, Munich, researcher found that fifty percent of introduced bird species become established, of which 34 percent become invasive. Mammals are even more successful colonists, with an amazing 79 percent finding a permanent home and 63 percent of those going on to become a pain in the proverbial for conservationists. That makes mammals almost fifty times more effective invaders than the tens rule predicts. How wrong can one be? Source: Jeschke JM (2008) Across islands and continents, mammals are more successful invaders than birds. Diversity and Distributions DOI: 10.1111/j.1472-4642.2008.00488.x Image: Tamara Strelnikova

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Oct

5

2007
 
 

Spiders from Mars (almost)



Alien arachnids hitch a lift along global trade routes Here's looking at youThe explosion in global trade has been accompanied by a sharp increase in the number of biological invasions. A study published recently in Diversity and Distributions makes a stab at unpicking the problem, asking where Europe’s alien spiders -- of which 87 species were reported between 1850 and 2000 -- have come from. Most unwanted imports arrive from the eastern Palearctic (Russia and many of its former Soviet states, Mongolia, China, Japan and Korea). Given the surge in manufacturing trade from these countries into Europe it’s hardly surprising. University of Bern, Switzerland, authors Manuel Kobelt and Wolfgang Nentwig predict a burgeoning number of introductions, many of which are potentially harmful to humans. Worse, climate change will be on the side of the eight-legged intruders. If that doesn’t bite, nothing does. Source: Kobelt M & Nentwig W (2007) Alien spider introductions to Europe supported by global trade. Diversity and Distributions DOI: 10.1111/j.1472-4642.2007.00426.x Related stories in Conservation magazine: Snakes on Planes Image © Al Braunworth

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Aug

3

2007
 
 

Nor any drop to drink



Conservation managers in a cruel bind over elephant control while scientists argue I'm young, but how long will the water last?Is switching off the water supply really the answer to the perennial “elephant problem”? That’s the subject of a heated debate going on in the pages of Diversity and Distributions right now. The naysayers, led by Kruger National Park’s Izak Smit, claim that artificial water holes make little difference to burgeoning elephant numbers. Among their reasons is the observation that elephant Loxodonta africana populations at Kruger -- South Africa's largest game reserve -- have yet to reach their carrying capacity. But the trouble is that they’re already high enough to be causing problems with a certain tail-less ape. The optimists, headed by Simon Chamaillé-Jammes at the Université de Lyon, say that conclusions have been reached too fast: they argue that turning off the taps can be a useful management tool, though not necessarily everywhere. Elephants across Africa are keeping an ear open for the result of the debate... Sources: Chamaillé-Jammes S, Valeix M & Fritz H (2007) Elephant management: why can’t we throw out the babies with the artificial bathwater? Diversity and Distributions DOI: 10.1111/j.1472-4642.2007.00415.x | Smit IPJ, Grant CC & Whyte IJ (2007) Elephants and water provision: what are the management links? Diversity and Distributions DOI: 10.1111/j.1472-4642.2007.00403.x Image © Nick Atkinson

Filed Under Community-based conservation, Economics and conservation, Endangered species, Habitat, Monitoring, Restoration, Socio-political issues | Leave a Comment

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Jun

27

2007
 
 

Hotspots feel the heat



They might have lots of species, but not necessarily evolutionary potential some like it hotSeventy-seven percent of terrestrial vertebrate species are found in areas declared as biodiversity hotspots, which occupy just 2.3% of the Earth’s surface. Unfortunately, as a recently published study shows, the sheer number of species isn’t the end of the story. Phylogenetic diversity -- the measure of how different species assemblages are -- is arguably more important, because greater differences offer more evolutionary potential. Earlier claims that biodiversity hotspots are also centers of high phylogenetic diversity were welcome, but according to Ohio State University biologists Miles Spathelf and Tom Waite they were overstated. Reanalysis of the same data shows that Madagascar, with its unique lemurs and weird mongooses, skewed the results beyond belief. Taking the fabled island out of the equation left hotspots no more likely (in fact even less likely) to harbor primate and carnivore phylogenetic diversity than anywhere else. Source: Spathelf M & Waite TA (2007) Will hotspots conserve extra primate and carnivore evolutionary history? Diversity and Distributions DOI: 10.1111/j.1472-4642.2007.00386.x Related story in Conservation magazine: Hotspot Mismatch for Most-Imperiled Species | Pollination Crisis in Biodiversity Hotspots Image © Simone van den Berg

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Apr

18

2007
 
 

At loggerheads with the Navy



show me the way to go home...Unexpected migratory patterns could land sea turtles in trouble Not all loggerhead turtles Caretta caretta wander across the oceans in the same direction, according to a study published recently in Diversity and Distributions. A team of scientists – led by University of Exeter, Cornwall marine biologist Brendan Godley – studied detailed satellite tracking data collected from twelve tagged turtles over a three-year period. The results show that while some turtles leaving nesting grounds in North Carolina head north, others swim south to warmer climes. For both, life is a delicate balancing act on the edge of the Gulf Stream, a question of trading life in warm water (cold water and ectothermy don’t mix well) against the energy-sapping currents. But the unexpected migratory patterns sound a warning against the US Navy proposal to create an underwater training battleground off south-eastern North Carolina: in the light of the new information, measures outlined to leave the turtles in peace might not go far enough. Source: Hawkes LA, Broderick AC, Coyne MS, Godfrey MH & Godley BJ (2007) Only some like it hot – quantifying the environmental niche of the loggerhead sea turtle. Diversity and Distributions DOI: 10.1111/j.1472-4642.2007.00354.x Image © Lucy Hawkes

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Apr

17

2007
 
 

A little more K, a bit less r



sometimes you're on top, others you aren'tInvading fruit flies don’t always follow the rules, but no one told them Fruit flies know a thing or two about invasion, and now they’re teaching biologists how it’s done. East of Madagascar, the island of La Réunion has recently played host to successive waves of incoming species; Ceratitis capitata, C. rosa and Bactrocera zonata. Writing in Diversity and Distributions, island biologist Pierre-François Duyck and colleagues describe how each new invader out-competed the existing incumbents to the extent that C. catoirii -- the formerly widespread endemic species -- is facing its final mango. The findings undermine current dogma that invasive species are “r-selected” (having traits that boost the number of offspring) rather than “K-selected” (producing fewer, more competitive offspring). Whether the results apply to other invaded ecosystems remains to be seen, but the fruit flies of La Réunion have told an enlightening tale. Source: Duyck P-F, David P & Quilici S (2007) Can more K-selected species be better invaders? A case study of fruit flies in La Réunion. Diversity and Distributions DOI: 10.1111/j.1472-4642.2007.00360.x Image © Scott Bauer Related stories in Conservation magazine: Nitrogen-Fixing Tree Paves the Way for Other Invaders Exotic Herbivores Promote Plant Invasions

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