Understanding how to conserve biodiversity within human-managed landscapes is increasingly important in a world where many natural lands are becoming transformed for human use. One opportunity for conservation is optimizing tree planting strategies within tree plantations or managed forests to maximize the biodiversity of other animals supported within the landscape before harvest. However, it is not currently clear whether or how mixed tree species management strategies within tree plantations can be used to support biodiversity conservation of associated organisms. Using a blocked and spatially controlled experimental design within the BiodiversiTREE tree diversity experiment located at the Smithsonian Environmental Research Center (SERC), we characterized the community structure and specialization of larval Lepidoptera (butterflies and moths) colonizing trees of 12 focal host species that are either surrounded by conspecifics (monoculture) or a mixture of 4 or 12 native species (polyculture). Lepidoptera is a useful focal taxon for examining this question as they are a diverse group containing many species of conservation concern, they exhibit a wide range of well-documented host specialization, and can easily be tied to a particular host tree.
Results/Conclusions
We find that over two years these host trees supported 189 species of moths and butterflies and that host trees surrounded by diverse mixtures of trees support a 62% higher abundance and 55% higher richness of caterpillars. We also examine host specialization and both spatial and temporal beta diversity patterns as well as determine whether composition of taxonomic, functional, or phylogenetic tree neighborhoods influence moth and butterfly host use the best. Further we link caterpillar use to leaf traits and leaf damage rates that may ultimately effect tree productivity. By characterizing patterns in lepidopteran diversity, degree of host tree specialization, and abundance and relating those metrics to a controlled manipulation of host tree diversity, we provide important insight into how forest management decisions impact the biodiversity of insect herbivores within human-managed landscapes.