Studies show plant litter often decomposes faster in the habitat from which it derives than in a different habitat—an idea known as home-field advantage (HFA). Within this literature, HFA is often found when litter between different functional groups of plants is tested (e.g. spruce v. aspen forests) as well as between disparate ecosystems (e.g. fields v. forests), but we have less understanding of how HFA works within an ecosystem. Furthermore, herbivores can alter plant community composition and redistribute nutrients via waste input, processes that can alter decomposition and nutrient cycling processes. However, it is unknown whether herbivore activities might mediate litter decomposition HFAs. To test this question, we performed a litter decomposition study in a small-mammal exclosure experiment in an old-field ecosystem. To test if the litter community from access plots decomposes more quickly in access plots (its ‘home’ environment) than in exclusion plots (its ‘away’ environment) and vice versa, we placed decomposition bags in a reciprocal design using litter collected from the five most abundant plant species common to both treatments from within treatment plots. The amount of litter from each species in the decomposition bag reflected the abundance found within the treatments, relative to the other species.
Results/Conclusions
Location placed (access or exclosure) (F = 9.21, p < 0.01), litter type (access or exclosure) (F = 27.20, p < 0.001), and removal date (F = 306.12, p < 0.001) all affect mass loss. Most HFA decomposition studies look for an interaction between litter type and location placed (home or away) to indicate a HFA. However, we found no litter type x location interaction (F = 0.14, p = 0.714). Instead, we found mass loss to be greater across access plots regardless of litter type, and greater across access litter regardless of plot treatment. By September, mass loss is not different between plot treatments (F = 1.74, p = 0.19,), but access litter showed greater mass loss compared to exclosure litter across plot treatments (F = 4.97, p = 0.03). Our results suggest rodents might select for both a plant community that is proportionately more labile, and a microbial community or microclimate more conducive to litter breakdown. So, while we do not find support for rodents creating a home-field advantage within litter decomposition, our results do indicate that rodents can greatly alter decomposition at a fine spatial scale.