Differential patterns of taxonomic and functional diversity for two groups of canopy arthropods across spatial scales

Authors: MAHON, MICHAEL - University Of Notre Dame; Penn, Hannah; CAMPBELL, KAITLIN - University Of North Carolina; CRIST, THOMAS - Miami University - Ohio

Submitted to: Ecosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/23/2023
Publication Date: 11/23/2023
Citation: Mahon, M.B., Penn, H., Campbell, K.U., Crist, T.O. 2023. Differential patterns of taxonomic and functional diversity for two groups of canopy arthropods across spatial scales. Ecosphere. Volume14, Issue11. https://doi.org/10.1002/ecs2.4700.
DOI: https://doi.org/10.1002/ecs2.4700

Interpretive Summary: Knowing why certain animals live within an area allows land owners and scientists to make better decisions for habitat conservation. Habitat, land use, and weather may all change the types of animals in a particular area. The animals that live in forests are affected by the species of tree, the location, how much forest is nearby, and weather. Ants and spiders are important animals of a healthy forest since they eat pest insects and are themselves food for other animals. This study looked at what affects ant and spider presence in forests and on certain trees. We collected ants and spiders by fogging 96 trees in 24 stands of 6 forest sites in 2 regions of the eastern USA with insecticide. Ants and spiders that fell from the trees were identified to species and grouped by their role in the ecosystem and how they move between locations. We also collected weather data and information about how much of the surrounding area was forested. The species of ants and spiders changed with each tree species. White oak, sugar maple, and beech trees had the most species of spiders, while tulip poplars had the lowest number of ant species. This may be due to differences in the amount of food and nest sites found on these trees. We also found that the species of spiders changed more between sites compared to ants, potentially due to their greater mobility. While the species of ants and spiders changed between sites, the number of roles they filled were similar, showing that different ants and spiders can contribute to healthy forests. Finally, we found that weather and the amount of forest changed which ants and spiders were present, but the impacts were different for ants and spiders. This means that the animals found in forests may change with changes in forest levels and weather.

Technical Abstract: Aim: Arthropod diversity is often linked to variation in resource use, dispersal ability, habitat connectivity, and climate factors that differ across spatial scales. The aim of this research was to examine how species richness, functional diversity, and community composition of two taxa differing in functional roles and dispersal ability are structured across spatial scales and to identify the relative importance of vegetation, climate, and landscape in explaining these patterns at different scales. Location: 96 trees in 24 stands of 6 deciduous forest sites in 2 ecoregions of the eastern USA Time period: 2000 Major taxa studied: Canopy dwelling ants (Hymenoptera: Formicidae) and spiders (Araneae) Methods: Organisms were collected from tree canopies using insecticidal fogging. Following identification, ant and spider taxonomic and functional beta diversity were partitioned across four hierarchical spatial scales (individual tree, forest stand, site, and ecoregion). The contribution of climactic, landscape, and vegetation variables was determined using model selection. Results: Ant and spider species richness, functional diversity, and community composition differed between taxa and across spatial scales. Alpha diversity (within trees) was lower than expected for both taxa and types of diversity, with host tree species supporting different species of ants and spiders. While beta components of species diversity among trees and forest stands was greater than expected for both taxa, spiders also showed significant levels of beta diversity among sites. Functional beta diversity was less scale-dependent than taxonomic beta diversity. Stand-level patterns of beta diversity were significantly predicted by variation in climate and landscape connectivity. Main conclusions: Strong controls of climate and landscape fragmentation on the diversity and community structure of both taxa indicate that anthropogenic climate change and land use change will alter canopy arthropod communities. Results also suggest that patterns of arthropod diversity among fragmentation metrics is influenced by differences in dispersal ability among taxa.