Understanding how species interact in a system may be critical to predict, and ensure the success of a restoration project. Although there is research currently showing the importance of interactions for restoration, most restoration studies only consider singular interactions, but net interactions may play a critical role in determining restoration outcomes. This may be especially true in arid systems because both positive and negative interactions have been shown to shape these communities. For example, the presence of neighbours around a plant may increase competition for resources, but the net effect on the community could be positive if the neighbours have traits that deter herbivory.
In arid ecosystems, shrubs are frequently identified as ecological keystone species because they affect the plant community through numerous mechanistic pathways including increasing soil moisture and soil nutrient levels, ameliorating abiotic stress, and reducing consumer pressure (see Filazzola and Lortie 2014 for a review, Figure 1). The animal community can also benefit from shrubs because shrubs can provide shelter, food, and shade. Conversely, shrubs can also indirectly increase negative interactions within their canopies by increasing plant densities (and promoting the establishment of non-natives that out-compete natives. These shrub induced net interactions have profound impacts on community structure and therefore need to be considered in restoration ecology.
The purpose of my research is to incorporate net interactions for the purposes of restoration in arid ecosystems using shrubs.