Many plant and animal species are being found further north and at higher elevations than previously observed. Rising temperatures, changing precipitation patterns and shifts in vegetation communities are changing the effective range and distribution of many native and agricultural species.
Some Species Move Quickly, and Some Move Slowly
It is likely that not all species in a community will respond to climate change in the same manner, or at the same rate. Some species may move readily across landscapes or habitats, as warming temperatures and changing ecological conditions alter their habitat. Less mobile species will change their distribution more slowly. Some, such as trees and other plants, will only be able to migrate through reproduction and seed distribution.
Differing rates of migration present a challenge for many species, which may have evolved to rely upon one another. For example, a pollinator and its preferred food plant may become separated. The problem of geographic separation is similar to the problem of temporal separation; in both cases, interdependent species may become separated as their environment changes.
What if Migration Isn’t Possible?
Barriers to migration — urban development or unsuitable habitat, for example — may limit the ability of some species or populations to shift their distribution. In extreme cases, these isolated populations may decline or go extinct. Such isolation is a concern for many mountain-adapted species, which often have no option but to migrate further uphill, until they have populated the highest elevation in a particular mountain range.
How Do Migrating Species Affect the Conservation Values of Land Protected by Land Trusts?
Species shifts pose complex management questions. Some land trusts are already implementing conservation strategies to maintain native communities and control invasive species. These goals may become increasingly difficult to achieve as species adjust their distribution in response to climate change.
The consequences of species migration include:
- Potential geographic split between species that rely on one another.
- Planting zones are shifting further north.
- Pests and diseases may shift their ranges into regions that have historically been unsuitable for them.
- Extinction may occur if a species is unable to migrate, becomes separated from another species it relies on, or is threatened by a new pest, disease or predator.