Life on Earth… predicted from space
Thursday 16 April 2009
Satellite images taken from space could help predict the consequences of climate change on wildlife, a recent study by ZSL scientists suggests.
Photographs taken from space have allowed scientists to quantitatively explore, for the first time at such scale, the relationship between vegetation and the abundance of herbivorous ungulates including giraffe, buffalo and antelope.
The Normalized Difference Vegetation Index (NDVI) is a satellite-based measurement indicating the amount of healthy vegetation on the ground, and is already in use by scientists studying climate change.
The ZSL study examined patterns of abundance for 13 species in 77 African national parks. Using the satellite measurements in combination with wildlife population densities estimated using traditional aerial and ground surveys, researchers were able to report a positive correlation between NDVI and the population size of ungulates on a continental scale.
It means there could be potential to predict ahead of time which species will die out first if there is a change in the base climatic conditions, giving conservationists a chance to focus on those species before it’s too late.
ZSL researcher Dr Nathalie Pettorelli, lead author of the study, explained: 'Several climatic models can be used to predict changes in NDVI, allowing scientists to forecast how climate change might affect vegetation. The correlation discovered means that the effects of climate change on wildlife could also ultimately be predicted quantitatively.'
She added: 'This is a really important step forward in helping to determine conservation priorities in a changing climate.'
Although not every species of animal studied showed a strong relationship between NDVI and abundance, researchers are confident these differences could be down to additional factors including poaching, predation or competition.
Dr Pettorelli explained: 'Even though we were unable to correct for several factors such as poaching intensity, predator density or soil nutrient status, we were still able to report a relationship between satellite indices and wildlife abundance.
'This suggests that the underlying relationship between satellite data and abundance might be even stronger than is apparent from our initial analysis.'
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