Detecting Ecosystem Performance Anomalies for Land Management in the Upper Colorado River Basin Using Satellite Observations, Climate Data, and Ecosystem Models

Yingxin Gu,Bruce K Wylie

doi:10.3390/rs2081880

Abstract

This study identifies areas with ecosystem performance anomalies (EPA) within the Upper Colorado River Basin (UCRB) during 2005–2007 using satellite observations, climate data, and ecosystem models. The final EPA maps with 250-m spatial resolution were categorized as normal performance, underperformance, and overperformance (observed performance relative to weather-based predictions) at the 90% level of confidence. The EPA maps were validated using “percentage of bare soil” ground observations. The validation results at locations with comparable site potential showed that regions identified as persistently underperforming (overperforming) tended to have a higher (lower) percentage of bare soil, suggesting that our preliminary EPA maps are reliable and agree with ground-based observations. The 3-year (2005–2007) persistent EPA map from this study provides the first quantitative evaluation of ecosystem performance anomalies within the UCRB and will help the Bureau of Land Management (BLM) identify potentially degraded lands. Results from this study can be used as a prototype by BLM and other land managers for making optimal land management decisions.

Highlights

Ecosystem performance (EP) provides important information to decision makers for land management
Site potential represents the long-term EP that averages out climatic variations but accounts for spatial variation in long-term EP associated with site conditions such as drainage, elevation, slope and aspect [8,28], soils, domain clusters [9], and surface geology
The validation results for big sagebrush at comparable site potential show that regions identified as persistently underperforming tended to have a lower range condition than normally expected from site potential; regions identified as overperforming tended to have a higher range condition. These results demonstrate that our ecosystem performance anomalies (EPA) maps agree with ground-based observations and provide reliable information for making land management decisions

Summary

Introduction

Ecosystem performance (EP) (i.e., a surrogate approaching ecosystem productivity) provides important information to decision makers for land management. Ecosystem performance is usually affected by site condition (e.g., drainage, elevation, slope and aspect, soils, and surface geology) [6,7,8,9], climate changes (e.g., precipitation and surface temperature) [10,11,12,13,14], natural disturbances (e.g., wildfires and floods) [12], and anthropogenic effects (e.g., heavy grazing) [15,16]. Interpreting ecosystem performance variation or ecological disturbance is complex because of the influences of weather, site potential, natural disasters and anthropogenic effects [17]. For moisture-limited rangelands, the interannual variation in vegetation productivity is significantly related to the local weather conditions, management practices, and disturbances. Wylie et al [1]

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