Cross-trophic resistance to forest insect pests
More than 450 non-native insects are currently established in forest ecosystems of the United States, causing a wide range of devastating ecological and economic impacts. The ability of forest plant diversity to reduce damage by phytophagous invasive insects, a kind of cross-trophic biotic resistance termed associational resistance, has been explored as a potential tool in mitigating the establishment and spread of invasive insects and their devastating impacts on native biodiversity.
Multiple mechanisms...
Associational resistance research has focused mainly on the role of the taxonomic diversity of non-host trees in diluting the concentration of host plants, and therefore decreasing pest invasion.
However, other mechanisms have also been hypothesized to contribute to associational resistance. For instance, non-host trees may reduce the physical or chemical detectability of host trees to invasive insect pests , or could increase number of natural enemies. Yet, research regarding these mechanisms of associational resistance remain underexplored.
Multiple aspects of biodiversity...
To further complicate our understanding of associational resistance, the roles of other aspects of diversity (beyond species richness and other metrics of taxonomic diversity) in activating these mechanisms is not well understood. A developing body of research suggests that functional, structural and phylogenetic diversity are able to enhance biotic resistance to invasive plants and to have a stronger effect on enhancing multifunctionality in an ecosystem. In the context of cross-trophic associational resistance, these aspects of diversity may be important drivers of resistance mechanisms as they may be more reliable indicators of dissimilarity between hosts and non-hosts.
To address this gap in ecological research, we are investigating the importance of these mechanisms of associational resistance, as well as the effects of structural, phylogenetic and functional diversity on activating them, through a macroecological perspective. Stay tuned for future developments!
