Large, undeveloped landscapes may be divided into multiple management units, which can create human-made boundaries that disrupt ecological connectivity. Credit: Paola Costa Baldi
Large, undeveloped landscapes are often divided into multiple administrative units. These units may be controlled publicly or privately, and be governed at the local, regional, or national level. They can also vary widely in their intended use, including recreation, conservation, or resource extraction. Even under a single ownership, some large tracts of undeveloped land can have multiple designations of use, such as switching from grazing lands to conservation lands.
What does this fragmented management mean for connectivity in the landscape? These human-made boundaries have the potential to create ecological boundaries, or ecotones. A recent commentary explores the link between ecological connectivity and management connectivity, and details possible mechanisms by which ecotones can arise.
A key message is that when large tracts of land are managed differently, sharp boundaries can arise in the landscape that ultimately make managing those lands more challenging. When ecotones develop, they alter the landscape at multiple scales and create unexpected differences that would otherwise be absent. Addressing the ways in which social borders influence environmental borders leads to more effective management plans over the long term.
There are several possible ways these ecotones can develop: through an increase in management units or management types; through long-term effects that magnify small management differences; or through changing degrees of collaboration between owners and managers of adjacent tracts. Each of these mechanisms affects how well-defined an ecotone might be in the landscape.
Artificial boundaries between administrative units can intensify management challenges, such as managing large landscapes for grazing. Credit: John Haynes
When ecotones arise across administrative units, there can be unintended consequences, particularly in three key management areas: fire, biological invasions, and grazing. Fire suppression or prescribed burning in only a few tracts of land can have impacts on neighboring tracts that are under different fire regimes, leading to less control of fires and unpredictable responses. Biological invasions can easily cross boundaries from a tract under no control to an adjacent tract under some control, rendering management efforts at limiting the invasion less effective or even moot. Differing intensities of grazing across tracts can lead to different species assemblages and vegetation structure, making it more difficult to predict which tracts will remain sustainable.
The overall message is that a lack of management connectivity leads to a lack of ecological connectivity. Cross-boundary collaboration is key to ensuring that different tracts of land are managed for the benefit of both themselves and neighboring tracts. Ecological processes don’t stop at human-made boundaries, and large landscapes benefit from management efforts that consider the bigger picture.
