The individual trees in the Amazon rainforest play a crucial role in keeping the rainforest intact. Not just because the trees together create the forest, but also because – together – they create the climate (through something called the shallow moisture convection pump).
Take home message: in order to preserve the Amazon, deforestation really has to stop completely. A ‘meeting in the middle’ compromise does not work – as (amplified by global climate change) that promotes devastating droughts in the remaining part of the forest.
We can all imagine that climate change-driven migration of species will have global consequences. But what do the actual effects look like – and how do these feed back on ecology, climate and human societies?
An analysis of IUCN’s Red List of endangered species places 10 drivers of the Holocene-Anthropocene Mass Extinction in order of severity. It concludes that classical environmental threats like deforestation, hunting and overfishing – in 2016 – still top the list of biodiversity killers.
Anthropogenic climate change is currently affecting 19 percent of species that are listed as threatened or near-threatened – making it the 7th extinction driver. (Stating the obvious: this position will change, as temperatures continue to rise.)
Anthropogenic climate change and land use change in the form of agricultural expansion (‘habitat conversion’ – a sweet description for deforestation) act as synergistic drivers of biodiversity loss – in a Costa Rican environmental experiment – literally drying out the natural diversity of species, bird species at least.
Again, the use of a geographical approach (and here defining biodiversity as ‘biotic intactness’) shows the Holocene-Anthropocene Mass Extinction is progressing faster then generally thought – and ‘biodiversity safe limits’, however arbitrarily defined, have already been passed on most of the planet’s land surface.
Whether you focus on mammals, birds, reptiles or amphibians – land vertebrates are in rapid decline everywhere around us, illustrating a general decline of Life on Earth – and a prelude to the Holocene-Anthropocene Mass Extinction, that is being underestimated in speed and severity.
The reason of this underestimation: demography – the decline of species populations. This is not always counted in when assessing the global ecological crisis, but if you do, you get to see that the actual trend is much worse than most people think…
If you live inside a heap of compost in someone’s backyard, your life may already feel quite miserable. But if you’re really tiny, at least you’re probably thinking your chances of surviving climate chance are –comparatively– okay.
Well, our dear little springtail –we hate to bring it to you– but science may have bad news. Sometimes it’s just not fair.
Predictive models that can forecast biodiversity decline under anthropogenic climate change used to be too simplistic, as these ignored crucial biological mechanisms such as demography, dispersal, evolution, and species interactions (for instance species competition and ecosystem dependence).
Fortunately these climate-biodiversity models are improving. But in order to also improve the quality of their biodiversity predictions these improved models now require more – and better data.