Mapping hidden resources

areas. But the situation is further complicated by the assessment of amphibian and reptile numbers in abandoned cacao plantations at the reserve edge, where the decline in numbers appears to be much smaller. The researchers considered whether changes in climate which have brought warmer weather to the reserve along with more wet days may have had an impact. The researchers found a rise of more than 1ºC in temperature over the 35-year period and a doubling of the number of wet days although no overall annual increase in rainfall. They considered whether these conditions changed the leaf litter on the forest floor. Nearly all of the species the team looked at rely on leaf litter to some extent, either using it for shelter, or feeding on insects that eat the leaves. Increasing heat and damp may have reduced the persistence of leaf litter and changed its physical ability to harbour amphibians and reptiles. The study revealed that frog numbers drastically declined with some species falling by more than 13 per cent per year between 1970 and 2005. Sharp declines in numbers of two salamander species, falling on average more than 14 per cent per year, were also recorded. Lizards also suffered with one species, the striped litter skink, down more than 10 per cent each year. The study was published in the Proceedings of the National Academy of Sciences (online). Many of the falls recorded elsewhere have been in high, mountainous regions and those have mostly been driven by the spread of fungus. But testing of 140 individuals of three species between June and November 2006 for the lethal fungus, showed no evidence of infection. And reptiles are not thought to be susceptible to it either. The researchers compared the conditions in the forest with those found in the neighbouring abandoned cacao plantations. And they believe the differing litter dynamics in the two habitats may explain the different results. " Because cacao trees have several leaf-flushing events each year, litter accumulation is greater in cacao plantations than it is in old-growth forests, " the researchers write. So the impact of changing weather conditions may have a lesser impact on leaf litter in these areas. And whatever factor or combination of factors is affecting the amphibians, the researchers highlight that declines in pristine habitats may be accompanied by simultaneous declines in other taxa. " Cross-taxa declines have been documented elsewhere, yet …