One issue constantly facing landscape ecologists is how to isolate the effects of fragmentation on ecosystems. This is because fragmentation is not a random process; it occurs disproportionately in productive areas that are valued for agricultural production. This results in a confounding of vegetation productivity and fragmentation, such that large intact areas tend to be less fertile, making it difficult to target the independent effects of fragmentation.
One way to get around this is to conduct fragmentation experiments. Fragmentation experiments deliberately manipulate the structure of patches to control for confounding effects and allow researchers to answer specific question in an experimental way. However, manipulating fragmentation at large spatial scales is extremely difficult, and so such studies are rare (but examples can be seen here, here, and here).
Last year, while at the pub with my good friend Brad Farmilo, I agreed to collaborate on work being conducted within one of the world’s few large-scale fragmentation experiments: the Wog Wog Fragmentation Experiment. This experiment was set up in 1987, and has produced a heap of great work (e.g. see here and here). A lot of this work focused on the influence of fragmentation on fauna, but Brad (and his supervisor John Morgan) was interested in looking at the more subtle effects of fragmentation, such as changes to soil chemistry, litter dynamics, and the temperature within fragments. These changes were of particular interest because the Wog Wog experimental fragments are imbedded in a pine plantation, which could result in different changes to those previously described in agricultural landscapes.
I’m really glad I decided to get involved and I’m happy to say that the outcome of this work has been published in Forest Ecology and Management. Briefly, we found fragmentation causes a series of changes to local environmental conditions, including increased canopy cover (due to the pine matrix ‘overtopping’ the forest fragments), leading to increased soil moisture and reduced temperatures in small fragments. We’re now figuring out how these changes directly influence plant species, as well as delving into the question of how fragmentation and other disturbances (e.g. herbivory) interact.
Check out this clip for more info on Wog Wog