Habitat loss and habitat fragmentation into smaller and smaller pieces are significant threats to terrestrial biodiversity. Human activities such as farming and urban expansion are just two causes. Another cause of habitat fragmentation in remote rural areas is when a new road is constructed to allow easier access to a new mine. Access roads benefit communities because it gives them better access to markets and distant urban centres. However, roads also enable people to get easier access to forests and woodlands that were previously difficult and costly to access. Deforestation and habitat loss inevitably follows.
A study undertaken on Barro Colorado Island in Panama and published last month in Nature, found that bird species are still being lost even after being protected on the island for 100 years. Twenty-seven percent of the 228 bird species found 100 years ago are no longer present.
Habitat fragments expose birds and other animals (including insects and arachnids) to edge effects, where the microclimate is different. Animals that cannot tolerate the changes in microclimate do not survive, though, depending on the patch size and species, it may take decades for the whole population to disappear.
Simply ensuring that some habitat patches are protected, even with connecting corridors, may not be an adequate long term management strategy to prevent biodiversity loss. The study of bird biodiversity on Barro Colorado Island by Jenna Curtis and her colleagues shows that a deeper understanding of the potential drivers of local extinctions is necessary.
We have libraries of information already available to help us make better-informed decisions and to better manage environmental impacts resulting from human activities. Opening up access to remote areas can give poor communities more opportunities for economic improvement. But it can also come at a cost. Good planning and coordination between community, government and developer would go a long way to getting it right.