Habitat fragmentation is a key driver of global biodiversity loss. Not only does fragmentation reduce habitat availability, but also has the potential to disturb natural species interactions that underlie important ecosystem services and stability. The phyllosphere (i.e. aboveground plant tissues) contains a diversity of microorganisms that can interact directly with macro-organisms through plant-mediated changes in herbivory and herbivore diversity. Using the interactions among phyllosphere microbiomes, plants, and herbivore communities, we can begin to understand anthropogenic disturbance effects on critical macrobial and microbial species interactions. With ~98% of Pine Rocklands of South Florida destroyed by urbanization and agriculture, the remaining habitat is highly fragmented, surrounded by a non-natural landscape matrix, which provides an opportune study system for habitat fragmentation. We selected 15 Pine Rockland fragments spanning a range of fragment size and habitat connectivities. We conducted quantitative surveys of herbivore and microbial communities March 2017- May 2017. Herbivory was determined from 10 haphazardly chosen leaves and classified into three types of damage. To characterize plant microbiomes, leaf tissue was collected for sequencing of 16S and ITS barcode genes (targeting bacteria and fungi, respectively) and the data will be processed using established QIIME methods, allowing for subsequent calculation of microbiome composition and diversity.
Results/Conclusions
Analysis of herbivory data of plants shows that species interactions between macro-organisms (i.e. plants and herbivores) vary with degree of fragmentation (i.e., habitat connectivity). The majority of the surveyed plants species (7/11) showed a significant or marginally significant relationship between habitat connectivity and at least one type of herbivore damage. Additionally, our results document variation among species for the strength and direction of the relationship between herbivore damage and connectivity, providing some of the first evidence that fragmentation may have host species-specific effects on herbivory among species within the same ecosystem. Surprisingly, our results show that even within species, different types of herbivory can differ in the strength and direction of their relationship with habitat connectivity. While most herbivory studies look at overall herbivory or a specific herbivore-plant relationship, this study highlights the complex effect of fragmentation on herbivory-mediated selection. These results to date suggest fragmentation has a more complex effect on herbivore-plant interactions than has previously been documented and demonstrates the need to account for both host and herbivore identity for understanding the effects of habitat fragmentation as well as in conservation planning of imperiled ecosystems.