A recent study indicates that when invertebrates in rainforests are eliminated thanks to logging, vertebrates can step up to fill important ecological roles. Almost half of all tropical rainforests have seen some amount of logging, and in those cases, local biodiversity can suffer. Invertebrates play a significant role in those ecosystems, helping to break down leaf waste.
Animals such as termites and millipedes help break down decomposing plants, while spiders and carnivorous ants help keep those creatures in check. For these reasons, invertebrates have long been considered the keepers of the rainforest, and the idea that human activity could impact those roles is a more recent one. But logging, often for agriculture, has led to changes in rainforest ecosystems, sometimes resulting in some species vanishing either from a particular region or all together.
If one or two invertebrates vanishes, there are generally enough other, similar species to fill in the gap. When this happens, it seems that vertebrates have been stepping in to help. Mice and shrews help move seeds about, which is important for diversity, while birds and bats help keep down the remaining invertebrate populations, so they don’t get out of control and upset the ecosystem further.
Researchers found that, in logged regions, invertebrates only filled about 60% of their usual functions, with vertebrates doing the rest. The outlier is plant decomposition, which vertebrates aren’t very good at. It seems that continued breakdown of leaf matter is being performed by bacteria or changing microclimates.
Unfortunately, there is much less diversity among vertebrates, and losing even one or two of those species from an area can have devastating consequences. Although it’s good that logged areas, with their reduced biodiversity, can still remain viable ecosystems, the fact that such ecosystems can adapt doesn’t mean they should be forced to do so. From an ecological standpoint, finding ways to reduce the impact of human actions on rainforests seems like the best option for ensuring their continued survival.