Characterizing Drought Effects on Vegetation Productivity in the Four Corners Region of the US Southwest

Mohamed El-Vilaly,Stuart Marsh,Kamel Didan,Armando Munoz,Michael Crimmins

doi:10.3390/su10051643

Mohamed El-Vilaly, Stuart Marsh + Show 3 more

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https://doi.org/10.3390/su10051643

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Abstract

The droughts striking the Colorado Plateau, where the Hopi Tribe and Navajo Nation Native American reservation lands are located, and their impacts have appeared slowly and relatively unnoticed in conventional national drought monitoring efforts like the National Drought Monitor. To understand the effect of drought-based drivers on vegetation productivity in the Hopi Tribe and Navajo Nation reservation lands, an assessment approach was developed integrating climate, land cover types, and topographical data with annual geospatially explicit normalized difference vegetation index (NDVI)-related productivity from 1989 to 2014 derived from 15-day composite multi-sensor NDVI time series data. We studied vegetation–environment relationships by conducting multiple linear regression analysis to explain the driver of vegetation productivity changes. Our results suggest that the interannual change of vegetation productivity showed high variability in middle elevations where needleleaf forest is the dominant vegetation cover type. Our analysis also shows that the spatial variation in interannual variability of vegetation productivity was more driven by climate drivers than by topography ones. Specifically, the interannual variability in spring precipitation and fall temperature seems to be the most significant factor that correlated with the interannual variability in vegetation productivity during the last two and a half decades.

Highlights

Droughts are a recurrent part of our climate and are considered one of the most complex and least understood phenomenon among all-natural hazards in terms of their impact on vegetation function [1,2,3,4]
The aim of this study is to evaluate and understand the potential drought drivers that have shaped the spatial–temporal variability in vegetation productivity in the region over the period of 1989–2014, and to provide valuable spatial information related to interannual variability and changes in vegetation productivity for planning and mitigation purposes, assisting managers and decision makers in maintaining biodiversity
We developed an assessment approach integrating seasonal climate, land cover types and topographical data with annual geospatially explicit normalized difference vegetation index (NDVI)-related productivity from 1989 to 2014 derived from 15-day composite multi-sensor NDVI time series data

Summary

Introduction

Droughts are a recurrent part of our climate and are considered one of the most complex and least understood phenomenon among all-natural hazards in terms of their impact on vegetation function [1,2,3,4]. In addition to the economic damage and impacts on natural resources, droughts have severe societal consequences causing displacement and migration and even political unrest [7,8,9]. In the southwestern United States, droughts are relatively a familiar phenomenon (Figure 1), due to land surface–ocean interactions [12]. In the southwestern United States, the severity of drought impacts on forested land have been well documented since the 1990s because of temperature increase recorded during this period [14,15,16]

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