Habitat heterogeneity, trophic links, and lichen assemblages: multiscale predictors of arthropod communities in Newfoundland forests

Abstract

Arthropods, a highly diverse and abundant groups of animals, are integral to ecosystem functioning worldwide. In forest environments, they act as pollinators, decomposers, nutrient cyclers, and more. However, these arthropod populations are susceptible to environmental changes, which are intensifying due to anthropogenic disturbances. Therefore, it is imperative to understand the dynamics of these communities in response to their surroundings. The aim of this thesis is to understand the variables that affect arthropod community structure in the forest, on trees and in soil. We hypothesized that habitat heterogeneity plays an important role in influencing arthropod diversity and abundance. This study was conducted in Newfoundland during the summer of 2022. We collected monthly arthropod samples from trees and soil in 45 replicate units distributed across three landscapes settings: Salmonier Nature Reserve, Pippy Park, and Outer Cove. Our findings underscore the significance of microhabitat variability, driven by differences in lichen communities, tree characteristics, and soil attributes, in shaping arthropod communities. Furthermore, our study found trophic correlations within and between habitat types, highlighting the importance of inter-group interactions. Finally, site variation underscores how landscape-level features influence arthropod abundance and diversity. Understanding the factors that influence arthropod assemblages can help develop proxy measurements for efficient monitoring of Newfoundland arthropod populations, while providing baseline measurements for future manipulative studies.