Year of Award

2025

Document Type

Thesis

Degree Type

Master of Science (MS)

Degree Name

Systems Ecology

Committee Chair

John Kimball

Commitee Members

John Kimball, David Naugle, Lisa Eby

Keywords

mesic resources, riparian vegetation, time series, riparian conservation, mesic restoration, conservation targeting, ecological connectivity

Subject Categories

Environmental Monitoring | Natural Resources and Conservation | Water Resource Management

Abstract

Mesic ecosystems in riparian areas and wetlands make up only 2% of western U.S. rangelands but support 80% of wildlife during dry periods, providing vital late-season forage and refuge when surrounding uplands dry out. Yet, mesic habitats are often overlooked in landscape-scale conservation planning. This thesis addresses two key gaps: understanding how mesic productivity responds to environmental change and developing frameworks to incorporate these habitats into current conservation strategies. Using 40 years of Landsat imagery (1984–2024), we examined long-term trends in late-season mesic vegetation productivity and its relationship with drought across the sagebrush biome. From 1984 to 2004, mesic productivity was strongly linked to drought indices (R² = 0.92). Since 2005, this relationship has weakened significantly (R² = 0.28), despite productivity increases. Random forest models further identified three main predictors of this productivity: perennial vegetation cover (indicative of groundwater access), density of nearby irrigated agriculture, and rising atmospheric CO₂ levels. These findings suggest water management practices like flood irrigation may help sustain mesic productivity during drought. Secondly, we developed a spatial framework connecting mesic habitat persistence to the Sagebrush Conservation Design (SCD), which guides conservation across 175 million acres of the sagebrush biome. While effective at identifying upland areas for protection, the SCD excludes mesic habitats—a notable omission given their ecological importance. Analysis of 18,861 watersheds revealed that only 9% contain abundant, persistent mesic vegetation near intact uplands. However, 31% demonstrate restoration potential. Notably, 65% of these restoration opportunities exist on private working lands, underscoring the role of collaboration and partnerships in conservation planning. To facilitate practical application, I created the Mesic Analysis Platform, an interactive web mapping tool that helps practitioners identify priority watersheds and specific stream reaches for restoration. This research emphasizes that effective rangeland conservation must treat mesic and upland ecosystems as integrated, maintaining water availability via natural processes and sustainable agricultural practices. This work advances a more connected, climate-resilient sagebrush biome by elucidating shifts in mesic resilience and providing targeted restoration tools.

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© Copyright 2025 Kristopher Robert Mueller