Wildlife habitat connectivity in the changing climate of New York’s Hudson Valley

Maintaining and restoring connectivity are key adaptation strategies for biodiversity conservation under climate change. We present a novel combination of species distribution and connectivity modeling using current and future climate regimes to prioritize connections among populations of 26 rare species in New York’s Hudson Valley. We modeled patches for each species for each time period and modeled potential connections among habitat patches by finding the least-cost path for every patch-to-patch connection. Finally, we aggregated these patches and paths to the tax parcel, commonly the primary unit of conservation action. Under future climate regimes, suitable habitat was predicted to contract or appear upslope and farther north. On average, predicted patches were nine times smaller and paths were twice as long under future climate. Parcels within the Hudson Highlands, Shawangunk Ridge, Catskill Mountains, and Harlem Valley had high species overlap, with areas upslope and northward increasing in importance over time. We envision that land managers and conservation planners can use these results to help prioritize parcel-level conservation and management and thus support biodiversity adaptation to climate change.

Long-distance plant dispersal and habitat fragmentation: identifying conservation targets for spatial landscape planning under climate change

Climate change presents a potentially severe threat to biodiversity. Species will be required to disperse rapidly through fragmented landscapes in order to keep pace with the changing climate. An important challenge for conservation is therefore to manage landscapes so as to assist species in tracking the environmental conditions to which they are adapted. Here we develop a stochastic spatially explicit model to simulate plant dispersal across artificial fragmented landscapes. Based on certain assumptions as to the dispersal mechanism, we assess the impact that varying potential for rare long-distance dispersal (LDD) has on the ability to move over landscapes with differing spatial arrangements of suitable habitat (clumped versus fragmented). Simulations demonstrate how the relative importance of landscape structure in determining migration ability may decrease as the potential for LDD increases. Thus, if LDD is the principal mechanism by which rapid large-scale migrations are achieved, strategically planned networks of protected habitat may have a limited impact on rates of large-scale plant migrations. We relate our results to conventional principles for conservation planning and the geometric design of reserves, and demonstrate how reversal of these principles may maximise the potential for conservation under future climates. In particular, we caution against the justification of large-scale corridors on grounds of climate change since migration along corridors by standard dispersal mechanisms is unlikely to keep pace with projected change for many species. An improved understanding of the dispersal mechanisms by which species achieve rapid migrations, and the way that these processes are affected by patterns of landscape fragmentation, will be important to inform future conservation strategies.

Climate change and the migration capacity of species

In a recent paper, McLachlan et al. presented evidence that migration rates of two tree species at the end of the last glacial (c. 10-20 thousand years ago) were much slower than was previously thought. These results provide an important insight for climate-change impacts studies and suggest that the ability of species to track future climate change is limited. However, the detection of late-glacial refugia close to modern range limits also implies that some of our most catastrophic projections might be overstated.

Conserving biodiversity under climate change: the rear edge matters

We review recent findings from the fossil record, phylogeography and ecology to illustrate that rear edge populations are often disproportionately important for the survival and evolution of biota. Their ecological features, dynamics and conservation requirements differ from those of populations in other parts of the range, and some commonly recommended conservation practices might therefore be of little use or even counterproductive for rear edge populations.

Adapting landscapes to climate change: examples of climate-proof ecosystem networks and priority adaptation zones

1. Climate change has been inducing range shifts for many species as they follow their suitable
climate space and further shifts are projected. Whether species will be able to colonize regions where
climate conditions become suitable, so-called ‘new climate space’, depends on species traits and
habitat fragmentation.
2. By combining bioclimate envelope models with dispersal models, we identified areas where the
spatial cohesion of the ecosystem pattern is expected to be insufficient to allow colonization of new
climate space.
3. For each of three ecosystem types, three species were selected that showed a shift in suitable
climate space and differed in habitat fragmentation sensitivity.
4. For the 2020 and 2050 time slices, the amount of climatically suitable habitat in northwest
Europe diminished for all studied species. Additionally, significant portions of new suitable habitat
could not be colonized because of isolation. Together, this will result in a decline in the amount of
suitable habitat protected in Natura 2000 sites.
5. We develop several adaptation strategies to combat this problem: (i) link isolated habitat that is
within a new suitable climate zone to the nearest climate-proof network; (ii) increase colonizing
capacity in the overlap zone, the part of a network that remains suitable in successive time frames;
(iii) optimize sustainable networks in climate refugia, the part of a species’ range where the climate
remains stable.
6. Synthesis and applications. Following the method described in this study, we can identify those
sites across Europe where ecosystem patterns are not cohesive enough to accommodate species’
responses to climate change. The best locations for climate corridors where improving connectivity
is most urgent and potential gain is highest can then be pinpointed.

Biodiversity management in the face of climate change: A review of 22 years of recommendations

Climate change creates new challenges for biodiversity conservation. Species ranges and ecological dynamics are already responding to recent climate shifts, and current reserves will not continue to support all species they were designed to protect. These problems are exacerbated by other global changes. Scholarly articles recommending measures to adapt conservation to climate change have proliferated over the last 22 years. We systematically reviewed this literature to explore what potential solutions it has identified and what consensus and direction it provides to cope with climate change.

Assessing species vulnerability to climate change

The effects of climate change on biodiversity are increasingly well documented, and many methods have been developed to assess species’ vulnerability to climatic changes, both ongoing and projected in the coming decades. To minimize global biodiversity losses, conservationists need to identify those species that are likely to be most vulnerable to the impacts of climate change. In this Review, we summarize different currencies used for assessing species’ climate change vulnerability. We describe three main approaches used to derive these currencies (correlative, mechanistic and trait-based), and their associated data requirements, spatial and temporal scales of application and modelling methods. Read More >