Morphology, Evolution, and Host Associations of Bee-Associated Mites of the Family Chaetodactylidae (Acari: Astigmata) with a monographic revision of North American taxaInteractive Effects of Environmental Variability and Neighborhood Diversity on Performance of Four Common Deciduous Tree Species in Eastern North America

Abstract

There is considerable evidence on the benefits of forest diversity for overall stand growth. Diversity has also been shown to buffer forests from climate disturbance. Knowing the species-specific impacts of diversity on tree growth is critical to assess, manage, and potentially design, resilient local forests under global change. We aim to address this knowledge gap using a combination of a dendrochronological study with a predictive modeling framework to understand the effects of forest neighborhood diversity across a gradient of June precipitation. We expected that: 1) under drought conditions increasing levels of diversity would impact species differently depending on their hydraulic strategies and 2) under typical/non-drought water availability, intraspecific interactions would have a more negative effect on growth than interspecific interactions, due to higher competition with resource overlap. We found that species do in fact respond to varying scenarios of diversity differently based on water availability. However, diverse ecosystems were not beneficial to drought tolerant Quercus species during high water availability, contrary to our prediction. Neighborhood dynamics are likely influenced by functional traits beyond hydraulic diversity including shade tolerance, water uptake depth, and growth strategy. Our findings indicate a potential trend in which Quercus species are released from competition under drought. The future environmental conditions in the region are predicted to have greater variability and clarifying neighborhood interactions helps to understand future trends in forest growth patterns.