NSFDEB-NERC-Wildlife corridors: do they work and who benefits?

Humans have modified over 75% of the global land area, leading to huge, negative impacts on biodiversity. A major consequence is that once large natural habitats have become fragmented into small islands of habitat within a sea of human-modified land such as farms and cities. Most species depend on dispersal (the movement of individuals from where they are born to a different location) to maintain healthy populations across landscapes. When their habitat becomes fragmented into small, isolated patches, species are often unable to disperse effectively between the remnant patches and this frequently results in population declines, loss of genetic diversity and local extinctions of species.

Understanding how best to manage landscapes that are fragmented is a key challenge. One of the most promising responses to fragmentation is to conserve or restore wildlife corridors, i.e. swaths of natural habitat between otherwise isolated habitat patches to facilitate dispersal, gene flow, and population rescue. Indeed, corridor creation is at the core of national (e.g. England's 25 Year Environment Plan) and international (e.g. the UN's Connectivity Conservation Project) environmental policies. Many conservation and environment agencies (e.g., Natural England, the USA's 22 Landscape Conservation Cooperatives) are designing - and public and private conservation investors are implementing - wildlife corridors. Huge sums of money in direct expenses and foregone development opportunities are being invested in corridors. However, we lack an understanding of if such corridors work. Most of what is known about corridor efficacy comes from experiments on model systems that do not resemble real-world wildlife corridors. New studies are needed to address the crucial questions: do corridors counter real-world fragmentation; and what corridor characteristics constrain effectiveness? To address these questions, we need to do fundamental research into the ecology of species' dispersal over large-scales and within complex, human-modified landscapes.

Existing experiments on corridors study the effects of corridors less than 0.5km long and less than 0.4km wide, much smaller than corridors in the real world. Our objective in this project is assess corridor effectiveness in a number of human-modified landscapes. We will address major knowledge gaps about the characteristics of effective corridors by studying 4-6 focal species in each of 20 landscapes in Europe and the Americas. Each of these 20 landscapes contains three types of habitat configurations: isolated habitat patches, pairs of patches connected by a corridor, and a large intact natural area. The landscapes are ideal because they vary in corridor widths (0.2-3km) and lengths (1-25km), which resembles the large scales at which habitat fragmentation and corridors are design in reality. Using genetic methods to assess how a variety of mammal species move in these different habitat configurations, we will identify whether mammals are able to use corridors at these large scales and which corridor characteristics (e.g. length, width) most strongly influence success. We will assess where and how unsuccessful corridors fail. We will also use novel analysis of species characteristics, such as body size, dispersal ability, brain size and reproductive rate, to identify which types of species are most likely to benefit from corridors and determine whether different types of species might require different types of corridors. Finally, we will use our new data in ecological models to test a range of methods for planning wildlife corridors, which will make the project useful to conservation managers globally.

Our project will deliver vital new information on how to make wildlife corridors successful for a large variety of species, will bring new understanding into species dispersal over very large scales, and will provide new methods for determining where to best invest resources for conservation.

The Wildlife Corridors project will be the first to assess connectivity metrics and corridor effectiveness in replicate human-modified landscapes, thus informing conservation policy and practice across the globe. Many conservation and environment agencies are designing - and public and private conservation investors are implementing - wildlife corridors. In preparing our proposal we have already engaged with key stakeholders and their letters of support highlight the substantial benefits they see emerging from our work.

For example, Dr. Gary Tabor, head of the IUCN's Connectivity Conservation Specialists Group, states that "proposed project will be of enormous value in helping Convention on Biological Diversity (CBD) member states implement their national targets for connectivity" during the 2020 meeting of the CBD, which will "for the first time include meaningful targets for connectivity." He explains "Most of what we think we know about corridors comes from experiments on "model systems" that do not resemble the corridors that are being proposed in real-world conservation efforts... this study will at last indicate what corridor widths and how much freedom from human disturbance is needed for a corridor to be successful."

To increase the likelihood that impact will be achieved, we will produce a Report for Conservation Planners (RCP) in NGOs and government. The RCP will be co-produced by co-authors we will recruit from the conservation planners working for Natural England (who provide advice and deliver duties across UK Government departments), UK county Wildlife Trusts (who implement the Living Landscapes initiative to improve connectivity), US land trusts (1300 trusts linked through a formal national network), US state wildlife agencies, and regional and national conservation NGOs, such as the Royal Society for the Protection of Birds in the UK, BUND in Germany, the European Green Belt, and The Nature Conservancy in the USA. These partners have supplied Letters of Support, indicating their engagement.

Development of the RCP will embrace a co-production model in which science users, science producers, and stakeholders sequentially (1) jointly identify specific decisions to be informed by science and define the scope and context of the problem, (2) help define research questions and methods, (3) make scientific inferences, and (4) develop strategies for the appropriate use of science. Although users and stakeholders are excluded from Step #2 (questions and methods are specified in this proposal), they will engage fully in the other aspects in three meetings. We will hold at least Meetings 2 and 3 at a global or continental meeting where many participants could attend in person while others participate remotely. Meeting 1: a virtual meeting that will start with an overview of our project, after which conservation planners and plan users describe the types of decisions they make, their constraints, and how science could help. Meeting 2: the group will discuss how our results can best inform planning and real-world decisions. Meeting 3: The rollout of the draft RCP, with illustrative applications, and discussion of final improvements. After the 3rd meeting, CLLC staff will prepare a visually appealing report, with key participants as co-authors, a highly visual one-page flyer to entice recipients to read the full report, and an infographic or short video animation for use in social media.

Associated impact activities will take place via all PI's frequent engagements with conservation professionals, We will use our high profile in this subject area and invitations to on-going workshops, meetings and conferences to share our findings with conservation planners and decision-makers. For example, CEH has developed a Memorandum of Agreement with the UK Department for Food and Rural Affairs which develops policy on the environment. Bullock will engage with Defra to ensure implications for policy are realised.