Archive for May, 2008

May

30

2008
 
 

Wise owls in germ warfare



Rare bird of prey threatened by malaria as competing species moves in

spotted owlSpotted owls Strix occidentalis are fighting a turf war with the increasingly invasive barred owl S varia; the two species competing for both food and limited nesting sites in old-growth forest. San Francisco State University researchers Heather Ishak, Ravinder Sehgal and colleagues now report in PLoS ONE how the spread of barred owls could also be increasing spotted owls’ risk of malaria and other blood-borne parasites. West coast barred owls were found to have significantly lower rates of infection than spotted owls inhabiting the same region. One possible explanation is that barred owls have better defenses – the Northern spotted owl population shows evidence of a recent genetic bottleneck, which could adversely affect their ability to mount an immune response. If true, barred owls could be acting as vectors for the parasites, passing them on to the increasingly threatened spotted owls, who promptly pass away. Source: Ishak HD, Dumbacher JP, Anderson NL, Keane JJ, Valkiūnas G, Haig SM, Tell LA & Sehgal RNM (2008) Blood parasites in owls with conservation implications for the spotted owl (Strix occidentalis). PLoS ONE DOI: 10.1371/journal.pone.0002304

Image: © Travis Manley

Read more on Endangered species, Habitat, Invasive species, Restoration, Monitoring | Post a Comment

Email This Post Email This Post

May

29

2008
 
 

The need for weeds



Turkish flora threatened by intensive agriculture, almost unnoticed

weeds“Weeds” provide valuable food for many species, yet their conservation status has been largely overlooked. A study by Cengiz Türe and Harun Böcük at Anadolu University, Turkey, now illustrates the extent of the oversight. Writing in Weed Research, they report on a worryingly high number of species – some 112 all told – listed on the wrong end of the IUCN’s Red List scale of endangerment. The intensification of arable farming in Europe has coincided with a dramatic decline in native plant species, hampering subsequent efforts to restore lost biodiversity. Turkey is particularly rich in endemic plant taxa, but modern agricultural practices are designed to eliminate non-crop species. Türe and Böcük make the bizarre, yet perfectly logical, suggestion that farmers should nurture weeds. Quite how farmers will react is another story… Source: Türe C & Böcük H (2008) Investigation of threatened arable weeds and their conservation status in Turkey. Weed Research DOI: 10.1111/j.1365-3180.2008.00630.x

Image: © Lane Erickson

Read more on Endangered species, Habitat, Invasive species, Restoration, Monitoring, Economics and conservation, Socio-political issues | Post a Comment

Email This Post Email This Post

May

24

2008
 
 

From cradle to grave



Tree pathogen brought to the US by keen gardeners, genetic study shows

dead treesSudden Oak Death, a straightforwardly named disease caused by the fungus Phytopthora ramorum, is gaining a worrying foothold in Pacific coastal forests. A study published recently in Molecular Ecology has traced the genetic origins of the pathogen in samples from dying trees at 14 Californian forests, together with samples taken from infected nursery plants in 12 states across the US. Leading an international team, Matteo Garbellotto, a University of California, Berkeley forestry pathlogist, has uncovered genetic evidence suggesting the fungus escaped into nearby forests from plant nurseries, where it affects many common species. If that’s not SOD’s law, nothing is. Source: Mascheretti S, Croucher PJP, Vettraino A, Prospero S & Garbelotto M (2008) Reconstruction of the Sudden Oak Death epidemic in California through microsatellite analysis of the pathogen Phytophthora ramorum. Molecular Ecology DOI: 10.1111/j.1365-294X.2008.03773.x

Image: © Ilbusca

Read more on Endangered species, Invasive species, Monitoring, Socio-political issues | Post a Comment

Email This Post Email This Post

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

Read more on Climate change | Post a Comment

Email This Post Email This Post

May

20

2008
 
 

Tom meets Jerry



Extinct thylacine DNA comes to life in a laboratory mouse

big dog Scientists have extracted DNA from a hundred year old pickled Tasmanian tiger and inserted into a mouse. The extinct marsupial Thylacinus cynocephalus was a remarkable example of convergent evolution, looking like and doing pretty much what modern eutherian canids (big fierce doggy predators) do. Writing in PLoS ONE, University of Texas molecular geneticist Richard Behringer and colleagues have shown it’s possible to go further than simply work out the DNA sequence of long-lost organisms. By swapping in the resurrected stretch of DNA – not a gene as such, but able to control the expression of one – the researchers made a remarkable discovery: the thylacine DNA worked the same way as the mouse’s own. The findings should pave the way to understanding how individual genes and their functions have evolved within species. A different kind of Jurassic Park perhaps lies ahead… Source: Pask AJ, Behringer RR, Renfree MB (2008) Resurrection of DNA function in vivo from an extinct genome. PLoS ONE DOI: 10.1371/journal.pone.0002240

Image: Benjamin A. Sheppard

Read more on Endangered species, Restoration, Tools and technology | Post a Comment

Email This Post Email This Post

May

15

2008
 
 

Fly in flowers



Neotropical insect biodiversity greater than previously thought

Still think we're all just bugs?DNA barcoding has once again revealed a wealth of unknown species, this time in neotropical insects. Writing in this week’s Science, a team of researchers led by Cornell College’s Marty Condon tell of their study of a group of fruit flies – the Blepharoneura – whose larvae munch their way unseen through species of plants in the particularly tasty Curcurbitaceae family, a group that includes cucumbers, pumpkins and melons. From a Central and South American study area measuring some 5500 km by 3000 km, they caught and reared 2857 flies from 24 host plant species, then ground them up and extracted their DNA for analysis. What they found was a remarkable degree of species diversity: 52 species of flies, many of which looked pretty much identical. However, this abundance of biodiversity was linked to a high level of specialization, with many species feeding not only a single plant species, but often just one sex or structure. With many species found at a lone site, the findings are likely to complicate conservation work, although welcome light has been thrown on the interaction between geography and diversity in this evolutionary epicenter. Source: Condon MA, Scheffer SJ, Lewis ML & Swensen SM (2008) Hidden neotropical diversity: greater than the sum of its parts. Science DOI: 10.1126/science.1155832

Image © Marty Condon

Read more on Endangered species, Habitat, Monitoring, Tools and technology | Post a Comment

Email This Post Email This Post

May

14

2008
 
 

Our fault? Sure is



Comprehensive analysis links global ecological changes to human activity

melting glaciers are down to usThirty five years’ worth of data covering hundreds of independent studies put beyond reasonable doubt the impact of human activity on the planet, according to a paper published today in Nature. NASA scientist Cynthia Rosenzweig and colleagues collated a diverse array of findings, allowing them to pin down the causes of physical (glacier shrinkage, warmer oceans and so on) and biological (early leaf burst, breeding seasons and algal blooms) changes that have been documented in recent decades. More than 95 percent of some 829 physical, and 90 percent of the nearly 29,000 biological changes they examined were in a direction consistent with a warming climate. If there’s any comfort to be drawn from the findings, it’s that climate warming is overwhelmingly the most important factor influencing changes in the natural world: habitat destruction, overfishing and pollution are mere trifles by comparison, so at least we know which problem to tackle first! Source: Rosenzweig C, Karoly D, Vicarelli M, Neofotis P, Wu Q, Casassa G, Menzel A, Root TL, Estrella N, Seguin B, Tryjanowski P, Liu C, Rawlins S& Imeson A (2008) Attributing physical and biological impacts to anthropogenic climate change. Nature DOI: 10.1038/nature06937

Image © Sburel

Read more on Climate change, Endangered species, Habitat, Marine, Fresh water, Community-based conservation, Socio-political issues | Post a Comment

Email This Post Email This Post

May

14

2008
 
 

No sleep ’til bedtime



First study of free-living wild sloths shows they’re not so lazy after all

wide awake clubWe all know sloths love their shuteye. But that should be captive sloths, as a study published this week in Biology Letters makes crystal clear. Niels Rattenborg, a sleep specialist at the Max Planck Institute for Ornithology and the paper’s lead author, attached newly-developed miniature electroencephalogram (EEG) recorders to three adult female brown-throated three-toed sloths Bradypus variegatus, who were otherwise minding their own easy-going business in the Barro Colorado Island rainforest. Average sleep times per day were 9.63 hours, over six hours less than a previous study of captive animals had suggested. Whilst neurophysiologists will welcome the study’s novel approach as a means to understanding the functions of sleep, conservationists will no doubt also heed the message that zoo animals just ain’t the same as the wild, free, altogether more awake ones. Source: Rattenborg NC, Voirin B, Vyssotski AL, Kays RW, Spoelstra K, Kuemmeth, Heidrich W & Wikelski MC (2008) Sleeping outside the box: electroencephalographic measures of sleep in sloths inhabiting a rainforest. Biology Letters DOI: 10.1098/rsbl.2008.0203

Read more on Restoration, Monitoring, Tools and technology | Post a Comment

Email This Post Email This Post

May

12

2008
 
 

Cheetah problem spotted



Scientists reach to the bottom of a mystery illness in captive animals

out for the count?A lethal disease is ripping through captive cheetah Acinonyx jubatus populations, hampering efforts to save the embattled felid from extinction. This week in PNAS, a research team led by Keiichi Higuchi at Shinshu University, Japan, claim that AA amyloidosis – a protein-folding disorder related to BSE (“mad cow” disease) – doesn’t arise quite as spontaneously as previously thought. Although animals that succumb are usually already suffering another affliction, the presence of amyloid proteins in the feces of infected animals provides a potential transmission route among individuals that are housed together. Even a giant kitty-litter tray won’t help, as the excreted infectious proteins can probably hang around in the soil too. Although the findings don’t definitively establish a link between sick cheetahs and their poop, they strongly suggest it’s a possibility to sniff out, so to speak. Source: Zhang B, Une Y, Fu X, Yan J, Ge F, Yao J, Sawashita J, Mori M, Tomozawa H, Kametani F& Higuchi K (2008) Fecal transmission of AA amyloidosis in the cheetah contributes to high incidence of disease. Proceedings of the National Academy of Sciences USA DOI: 10.1073/pnas.0800367105

Image © Eric Gevaert

Read more on Endangered species, Restoration, Monitoring, Tools and technology | Post a Comment

Email This Post Email This Post

May

8

2008
 
 

The ghost at the feast



Loss of seed dispersers has far-reaching ecosystem impacts

one hungry tortoise

Rewilding is a controversial topic: when important native species have gone, is it OK to bring in exotic alternatives to perform an essential ecosystem role? This week in PLoS ONE Stanford University researcher Dennis Hansen and colleagues report on their experiments to help save the critically endangered tree Syzygium mamillatum, which grows only on the famously dodo-devoid oceanic island of Mauritius. Plants often depend on large herbivores to disperse their seeds: Hansen’s experiments addressed the Janzen-Connell effect, whereby seedling survivorship increases dramatically with dispersal distance by virtue of escaping the specialist herbivores that plague its poor mother. Using Aldabra tortoises Aldabrachelys gigantea as willing stand-ins for the two extinct Mauritanian giant tortoise species Cylindraspis triserrata and C. inepta, Hansen’s team recorded seedling survival in relation to distance from a mature tree and whether it had passed through the gut of one of those lucky tortoises. Despite relatively few gut-passed seeds surviving the ordeal, and coupled with a lower germination rate, the fact that they are likely to be deposited many meters from their parent tree could mean an overall benefit to tortoise seed predation. So, should tortoises be brought in to help save S. mamillatum? After all, they’re not exactly the most difficult animals to keep track of… Source: Hansen DM, Kaiser CN & Müller CB (2008) Seed dispersal and establishment of endangered plants on oceanic islands: the Janzen-Connell model, and the use of ecological analogues. PloS ONE DOI: 10.1371/journal.pone.0002111

Image © Dennis Hansen

Read more on Endangered species, Habitat, Invasive species, Restoration, Monitoring, Socio-political issues, Tools and technology | 1 Comment

Email This Post Email This Post

keep looking »