Much more is known about the impacts of connectivity on animal movement than plant movement. Credit: Julian Colton
While the role of landscape connectivity on animals has been extensively studied, less research has focused on plants beyond their role in pollination. However, plants are a large part of the foundation of ecosystems, and the negative consequences of habitat fragmentation and habitat loss on plants can potentially impact the ecosystem as a whole.
A recent study focuses on several aspects of habitat linkages through the lens of plant conservation, examining the benefits and shortcomings as well as making recommendations for more suitable alternatives.
One main focus is on dispersal, and the fact that the impact of corridors on animal dispersal is much better studied than the impact on plant dispersal. One reason for this is the difficulty in studying plant movement, since plants are sessile and movement through corridors occurs over a longer period of time compared to animals.
Not only is less known about the impact of corridors on plant dispersal, it is also more difficult to create a corridor for plant movement. This is because plants are often dependent on animals and other external forces to move through habitats. Corridors are also often longer than the dispersal capacity of a plant species, meaning that secondary dispersal events are necessary. Corridors can act as stepping stones when plants establish themselves and reproduce in the corridor. However, this often takes several generations, and means it may take years for complete movement through the corridor and establishment of a new habitat.
Another factor to take into account for plants and corridors is the interactions between corridors and dispersal agents. These processes have been well studied at the Savannah River Site experimental corridors, where almost twenty years of research has shown that species richness increases at a more rapid rate in connected habitat patches compared to unconnected patches.
The impact of corridors on plant dispersal is an ongoing question. The lack of a definitive, agreed upon definition of corridors also makes it challenging to compare studies and make generalizations. Some studies have suggested that corridors might negatively impact the diversity and species composition of plant communities. Some worry that invasive species may benefit from corridors, but invasive species tend to be good at spreading regardless of the presence of corridors.
One suggested alternative that might avoid some of the potential problems of traditional corridors is semi-open corridors. Semi-open corridors have the ability to connect different types of habitats and promote dispersal through multiple habitat types. They not only provide a linkage, but also act as stepping stone habitats for a variety of species with different habitat requirements. Further investigation is needed to evaluate whether semi-open corridors could counteract the effects of habitat fragmentation, but if found to be the case would provide another useful tool for biodiversity conservation.
Resources
Travers, E., Härdtle, W. and Matthies, D. 2021. Corridors as a tool for linking habitats – Shortcomings and perspectives for plant conservation. Journal for Nature Conservation 60: 125974.
Plant diversity benefits from corridors over long time scales (December 2019)
