Determinants of moth diversity and community in a temperate mountain landscape: vegetation, topography, and seasonality

Steven A Highland,Jeffrey C Miller,Julia A Jones

doi:10.1890/es12-00384.1

Abstract

Macromoth diversity, abundance, and community structure in the topographically complex HJ Andrews Experimental Forest and LTER site was studied on the west slope of the Cascade Range, Oregon. Data on 493 macromoth species (62,221 individuals) was sampled eight times/year at 20 locations from 2004 to 2008 and examined using multivariate statistics and generalized additive models to determine the importance of topography and vegetation on moth community assembly and diversity. Significant differences exist between moth communities at lower and higher elevations. High‐elevation moth communities are far more variable inter‐annually, whether associated with high‐elevation forests, meadows, or clearcuts. Low‐elevation young and old gymnosperm forests and riparian forests are more stable and predictable communities having less inter‐annual variability. High‐elevation communities show more intra‐annual variability than low‐elevation communities. Low‐elevation moth communities are more abundant than high‐elevation communities and typically associated with the most common, abundant species of macromoths in the study. High‐elevation communities, by contrast, are associated with less abundant, more evenly distributed species, as well as with rare moth species. Macromoth community structure and diversity were related to year or sample period and structural descriptions of vegetation communities, but not related to known host‐plant diversity. High‐elevation communities are threatened by contraction of montane meadows and climate change which, given the variability in high‐elevation communities, could severely impact the biological diversity of the western Cascades landscape. Nocturnal macromoths represent an important potential indicator of ecosystem health and change.

Highlights

Nocturnal macromoths are a highly diverse and ecologically important group of insects that play key roles in herbivory, pollination, prey for birds and bats, and are potential indicators of ecosystem health and change across a wide variety of landscapes (Erhardt and Thomas 1991, Kitching et al 2000, Summerville and Crist 2004)
Studies addressing community structure and diversity of nocturnal macromoths have mostly been undertaken in relatively flat topography and/or homogenous vegetation types (Usher and Keiller 1998, Kitching et al 2000, Summerville and Crist 2003, 2004, Ober and Hayes 2010, Summerville 2011)
Using a non-metric multidimensional scaling (NMDS) ordination of the fully aggregated moth data (Fig. 1), we identified the two traps in each structural vegetation category that were closest to the centroid of that category and designated those two traps as representative of the moth communities associated with that vegetation category

Summary

Introduction

Nocturnal macromoths are a highly diverse and ecologically important group of insects that play key roles in herbivory, pollination, prey for birds and bats, and are potential indicators of ecosystem health and change across a wide variety of landscapes (Erhardt and Thomas 1991, Kitching et al 2000, Summerville and Crist 2004). 2006, Hilt and Fiedler 2006, Beck and Chey 2008), but few have examined multi-family diversity and communities. Most of these studies found that both elevation and plant species distributions are important predictors of moth family distributions and diversity patterns. Studies addressing community structure and diversity of nocturnal macromoths have mostly been undertaken in relatively flat topography and/or homogenous vegetation types (e.g., grassland, deciduous forest, riparian forest) (Usher and Keiller 1998, Kitching et al 2000, Summerville and Crist 2003, 2004, Ober and Hayes 2010, Summerville 2011). Less is known about how nocturnal macromoth community structure and diversity respond to steep vegetational and elevational gradients at the landscape scale in temperate regions

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Discussion

Conclusion