A reintroduced ecosystem engineer species may exacerbate ongoing biological invasion: selective foraging of the Eurasian beaver in floodplains (2020) Juhasz et al., Global Ecology and Conservation, https://doi.org/10.1016/j.gecco.2020.e01383
The reintroduction of species to an area from which they have been wiped out can have benefits which extend beyond that one species. Often they can restore ecological functions that have since been lost, which can result in everything from an increase in biodiversity to restructuring of an entire landscape.
That last example might seem a bit far-fetched, but beavers (Castor fiber) are capable of just that. Their damming activities can change river flows and restore healthy floodplains, and as such beavers are the target of a large reintroduction campaign now occurring throughout much of Europe.
But what happens when a species like the beaver is reintroduced to an ecosystem that has seen significant changes since it has been gone, like the introduction of invasive species? Today’s authors wanted to find out whether or not the presence of the beaver benefited native plants, or whether it made things easier for the invasive species.
Tasmanian Devil at the Zoo Duisburg, in 2017. The only zoo in Germany that keeps them. (Credit: Mathias Appel / CC0)
With the seemingly endless stream of bad news relating to the environment we’re often faced with these days, hearing ecosystem restoration or conservation success stories are always a welcome relief. With the number of species that have been displaced from their native habitats, the news of an endangered species being successfully introduced to a new area should be shouted out. So you cannot blame a conservation geneticist like me for jumping happily when I heard news of the release of the European bison and Tasmanian devil back to their native habitat.
The Burmese python, which has spread throughout the Everglades in Florida as a result of accidental or intentional releases by pet owners (Image Credit: US NInvaders, Aliens, and tational Park Service, Public Domain Mark 1.0, Image Cropped)
Language is important. It’s a lesson many biological scientists would have learned a long time ago if we hadn’t kept social sciences at such a wary arm’s length. Ecologists have a tendency to label and relabel ecological concepts (anyone up for a debate about the word ‘niche’?), species and even global phenomena (think global warming vs. climate change) based on anything from shifts in public perception to new findings that challenge our earlier labels.
African forest elephants populations are declining rapidly due to local human pressures. But is it fair to expect other humans to live among potential threats to their livelihood? (Image Credit: US Fish and Wildlife Service Headquarters, Public Domain Mark 1.0, Image Cropped)
Some species of animal do a better job of capturing our attention than others. For many of us, the exotic nature of these animals is often the kicker. Think of the majesty of an elephant strolling across the savannah, or the romanticised stalk of the tiger through the jungle. Yet while the public ogles these creatures in the wild or at the local zoo and mourns the decline of their wild populations or the reported deaths of iconic individuals, we often ignore the harsh reality: that there are people who live in close proximity to these animals, to whom they represent a day-to-day threat. So how does our attitudes to charismatic species in places like Africa and Asia here need to shift, and where can we start?
When species like this toucanet are lost, the interactions that they are a part of are lost too. So how can we restore them? (Image Credit: Jairmoreirafotografia, CC BY-SA 4.0, Image Cropped)
Estimating interaction credit for trophic rewilding in tropical forests (2018) Marjakangas, E.-L. et al., Philosophical Transactions of the Royal Society of Biology, 373, https://dx.doi/10.1098/rstb.2017.0435
We have reviewed more than enough papers on biodiversity loss to entitle us to skip the whole “losing species is bad” spiel (see here, here and here). But what we haven’t talked about is that when some species are lost, specific interactions that those species participate in disappear from an ecosystem. Those interactions range from the minute to the crucial. One such crucial example is that of seed dispersal, whereby specific plants rely on specific animals to disperse their seeds, thus maximising biodiversity in other parts of the forest and creating a positive feedback loop.
Naturally, conservationists will want to reintroduce animals to propagate some of these reactions. But as is always the case in conservation, maximising return is absolutely essential when you’re faced with limited resources and a lot of ground to cover. Today’s authors wanted to develop a system for maximising the effect of species reintroduction.
Image Credit: Per Harald Olsen, NTNU, CC BY 2.0, Image Cropped
In my previous posts on rewilding and wild boar, I talked about the effects of reintroducing species that were previously found in Norway. Now, I want to talk more about the large carnivores in Scandinavia which serve as protection against invasive species. This opinion piece is coming from an ecologist and a foreigner, so treat this like a Scandic breakfast buffet and take what you want.
Image Credit: Doug Smith, NPS, Public Domain, Image Cropped
Can you imagine a wild Scandinavia filled with untamed forests, wild boar, and large predators (and maybe a stray Viking)? This is the dream of some scientists advocating for the reintroduction of species once found in Europe that have either been hunted to extinction or driven out by intensive agriculture. The reintroduction of species, particularly animals dubbed “ecosystem engineers” such as beavers and large carnivores are of special interest due to the positive landscape-level effects of these species.