Competing hypotheses explaining home field advantage: Comparing decomposition in native and non-native leaf litter
Home Field Advantage (HFA) is a term that has been used frequently to describe the phenomenon of leaves degrading faster in the presence of plants of the same species (home) than they would elsewhere (away). The Substrate-quality Matrix-quality Interaction (SMI) hypothesis theorizes that HFA is driven by biochemical similarity of resources provided by leaves and the environment, resulting in decomposer taste preferences. Alternatively, HFA may be the result of species-specific interactions that are not captured by broad measures of resource availability. In addition, it is unclear whether HFA is driven primarily by the microbes on the leaves or the invertebrates in the soil choosing which leaves to devour.
In this study, we tested these drivers of HFA by using leaves that are native to the test site as well as non-native leaves from a site 720 miles away. A decomposition study was conducted with litterbags, using two mesh sizes. One mesh was large enough to allow all invertebrates to colonize, and the other excludes invertebrates >100um.
Initial results with coarse mesh were consistent with traditional HFA patterns, but only for leaves native to the test site, not non-native leaves. This leads us to believe that preference by microbial decomposers is not the only important aspect of HFA, and invertebrates may be more important in mediating HFA than microbes. It also suggests that HFA is driven more by species specificity in an environment than by broad resource similarity of and the environment.