Insect community responses to climate and weather across elevation gradients in the Sagebrush Steppe, eastern Oregon

Open-File Report 2016-1183
Prepared in cooperation with the Bureau of Land Management under Interagency Agreement L10PG00804 for the project: “Forecasting Insect Community Responses to Changes in Land Management and Climate in Upper Columbia Basin Sagebrush Steppe”
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Executive Summary

In this study, the U.S. Geological Survey investigated the use of insects as bioindicators of climate change in sagebrush steppe shrublands and grasslands in the Upper Columbia Basin. The research was conducted in the Stinkingwater and Pueblo mountain ranges in eastern Oregon on lands administered by the Bureau of Land Management.

We used a “space-for-time” sampling design that related insect communities to climate and weather along elevation gradients. We analyzed our insect dataset at three levels of organization: (1) whole-community, (2) feeding guilds (detritivores, herbivores, nectarivores, parasites, and predators), and (3) orders within nectarivores (i.e., pollinators). We captured 59,517 insects from 176 families and 10 orders at the Pueblo Mountains study area and 112,305 insects from 185 families and 11 orders at the Stinkingwater Mountains study area in 2012 and 2013. Of all the individuals captured at the Stinkingwater Mountains study area, 77,688 were from the family Cecidomyiidae (Diptera, gall gnats).

We found that the composition of insect communities was associated with variability in long-term (30-yr) temperature and interannual fluctuations in temperature. We found that captures of certain fly, bee, moth, and butterfly pollinators were more strongly associated with some climate and vegetation variables than others. We found that timing of emergence, as measured by first detection of families, was associated with elevation. When analyzed by feeding guilds, we found that all guilds emerged later at high elevations except for detritivores, which emerged earlier at high elevations. The abundance of most taxa varied through time, mostly in response to temperature and precipitation. Of the pollinators, bees (particularly, Halictidae and Megachilidae) peaked in abundance in late June and early July, whereas butterflies and moths peaked in August. Flies peaked in abundance in July.

Overall, our interpretation of these patterns is that insect communities respond positively and negatively to weather and local vegetation more than to long-term climate. Given increasing variability in weather and high probability of extreme weather events, insect communities in sagebrush steppe also may experience considerable fluctuations in composition and abundance, as well as phenology. These findings have implications for many ecosystem services, including pollination, decomposition, and food resources for predatory birds and other vertebrates.

Suggested Citation

Pilliod, D.S., and Rohde, A.T., 2016, Insect community responses to climate and weather across elevation gradients in the Sagebrush Steppe, eastern Oregon: U.S. Geological Open-File Report 2016–1083, 50 p.,

ISSN: 2331-1258 (online)

Study Area

Table of Contents

  • Executive Summary
  • Introduction
  • Methods
  • Study Design and Sampling Methods
  • Section I. Assessment of Sampling Design
  • Section II. Insect Community Composition
  • Section III. Insect Phenology
  • Management Implications and Future Directions
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title Insect community responses to climate and weather across elevation gradients in the Sagebrush Steppe, eastern Oregon
Series title Open-File Report
Series number 2016-1183
DOI 10.3133/ofr20161183
Year Published 2016
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Forest and Rangeland Ecosystem Science Center
Description vi, 50 p.
Country United States
State Oregon
Other Geospatial Sagebrush Steppe
Online Only (Y/N) Y
Google Analytic Metrics Metrics page
Additional publication details