Managing range shifts under climate change across new habitats and borders

Barred owl

The barred owl (Strix varia), native to the eastern United States, shifted its distribution westward and began to outcompete the endangered spotted owl (Strix occidentalis).

Climate change is predicted to cause many species to shift their distributions. How we manage redistributed species depends not only on their ecological value, but also their economic and social values.  These values may not always align with each other, and can sometimes act at odds. For example, a fish species that expands its range into new waters may be commercially valuable in the new region, but also outcompete historically native species.

A recent perspective on climate change and species redistribution highlights a few of the bigger questions associated with the management of range shifts and how differences in values will shape ecosystems of the future.

One main question that stands out: how do we define what an ecosystem should look like in the future?  Historically, management policies of redistributed species defined them as one of three types in order to facilitate decisions.

Persecuted species, which expand their range but in way that negatively impacts historically native species, are seen as invaders despite the face that they may be native elsewhere. Protected species, which automatically receive legal protection in their new range, depend on detection in the new area and are more likely to receive pro-active management if they are in decline or of recreational value. Ignored species, which may show up in an area in very small numbers, can easily shift from being vagrants to being pioneers of redistribution under climate change.

Although all of these shifts can result from “natural” causes (i.e. non-anthropogenic), the management response to their arrival in a new region can vary based on the perception of their value and whether or not they “should” be there.  When species distributions shift due to climate change, decisions may be also based on the extent to which a society believes humans should mitigate anthropomorphic-driven changes.

Kokerboom Forest Namibia

The quiver tree (Aloidendron dichotomum) has shrinking ranges in Namibia but healthy populations in South Africa – at what point should either country begin active management?

Once species redistribution does start to occur, at what point should active management begin, particularly as many species that shift under climate change will be those with limited economic or recreational value?  This question becomes more complicated when species shift across geopolitical borders, since a species’ value may be high in one society and low in another. Active management, such as human assisted migration, may be considered legitimate in some cases but illegitimate in others depending on societal values.

One way for managers to make effective decisions on which species require intervention is to establish baseline monitoring of all species regardless of their perceived value. The complications of managing redistributed species mean that success is more likely if management agreements are put into place before large-scale range shifts occur.  Current management under climate change, such as the creation of landscape corridors, the use of buffer zones, and increased research into population viability, is a first step toward conserving biodiversity under climate change.

Overall, global partnerships will likely be key in managing redistributed species, since many species are likely to cross political borders and therefore cross regions with differing societal values. Establishing protocols now, before species redistribution becomes even more complicated, may ensure that management practices are effective.  Global biodiversity is about to become redefined, and acting in a global way will be necessary for the future conservation of all species.

Resources

Scheffers, B. R., and G. Peci. 2019. Persecuting, protecting or ignoring biodiversity under climate change. Nature Climate Change 9: 581-586.

2019-09-30T08:57:24-04:00 September 27th, 2019|

About the Author:

Heather Cayton
Heather Cayton is the Managing Director of ConservationCorridor.org and a Research Assistant at Michigan State University. She received her B.S. from the University of Virginia and her M.S. from Virginia Tech, and has spent over 10 years studying corridors and rare butterflies in North Carolina.