Peer-reviewed. Literature Review. Ecology.
University of Leeds news
Efforts to join up isolated plant and animal habitats across the world should also protect against unintentionally harming them, new research shows.
The paper, led by the Universities of Leeds and Oxford and published today in Nature Reviews Biodiversity journal, states that work to connect fragmented wildlife habitats is essential - but it may also pose ecological risks including the unintentional spread of wildlife diseases and invasive species.
Wildlife or ecological corridors are areas of land connecting isolated habitats, allowing animals and plants to move, adapt and survive. They are essential for promoting biodiversity and enabling populations to breed and increase in number and diversity. Examples include the European Green Belt, a 12,500km corridor of habitats linking protected areas across 24 countries, and Banff National Park's wildlife crossings in Canada, where a network of overpasses and underpasses has reduced vehicle collisions with elk and deer by more than 95%, allowing them to move safely between areas.
Lead author Dr Josh Firth, Associate Professor of Behavioural Ecology in the University of Leeds' School of Biology, said: "Building a well-connected world is essential for biodiversity. But when making decisions about how best to protect, restore and create habitat links, we need to incorporate potential risks so that we can prioritise the links that deliver the strongest overall gains for nature."
Using several recent studies, the authors assessed emerging evidence of the potential negative impacts of connecting habitats for wild populations.
Previous research has linked increasing habitat connectivity with the spread of diseases such as amphibian chytridiomycosis. Caused by chytrid fungus, it is threatening amphibian species across Europe and North America.
Senior author Dr Sarah Knowles , in the University of Oxford's Department of Biology, said: "Connectivity often helps populations persist, yet it can also create pathways for pathogens. Recent studies on African swine fever in wild boar show that disease can move more quickly through linked landscapes, illustrating the importance of considering transmission risks."
The authors also point to a variety of other risks that creating habitat connections can bring, such as wildfire spread, where corridors act as 'fuel pathways' that elevate fire frequency and extent.
The researchers make several recommendations of cost-reduction strategies for consideration when designing and implementing biodiversity corridors in high-risk settings.
Prevent disease by building in basic disease surveillance and hygiene including the ability to temporarily close corridors during outbreaks and using carcass removal or vaccination strategies.
Inhibit invasive species by treating proposed new links as potential invasion pathways, and running pre-project risk checks as well as planning early detection and rapid responses. Where suitable, using habitat filters that favour native species and deter likely invaders.
Avert disturbances such as wildfires in high-risk areas by designing corridors with breaks and buffers, less-flammable strips, and use local risk modelling (including seasonal patterns) to avoid creating spread.
The paper states that the same tools already used to plan habitat links, such as modern mapping, animal tracking and large-scale biodiversity monitoring, can also flag where extra care is needed, and calls for further work to improve understanding of when and where costs arise.
Co-author Dr Ivan Jarić , of Université Paris-Saclay, said: "Reconnecting areas brings clear ecological benefits, but as environments change various risks can emerge. For instance, removing dams to restore connectivity in the Elwha River in Washington, USA, has helped biodiversity including by reviving native fish populations, but it has also increased the downstream spread and growth of several invasive plant species. It's a useful example of how new connections can sometimes open routes for unwanted species, and why strategies should be considered to mitigate negative effects."
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