Livestock management, beaver, and climate influences on riparian vegetation in a semi-arid landscape

Abstract

Riparian and aquatic habitats support biodiversity and key environmental processes in semi-arid and arid landscapes, but stressors such as conventional livestock grazing, wildfire, and drought can degrade their condition. To enhance habitat for fish and wildlife and increase resiliency in these critical areas, land managers in the interior western United States increasingly use alternative grazing strategies, beaver management, or beaver dam surrogates as low-effort, low-expense restoration approaches. In this study we used historical archives of satellite and aerial imagery spanning three decades to characterize riparian vegetation productivity and document beaver dam occurrences, then evaluated vegetation productivity relative to land management associated with livestock grazing and beaver dam densities while accounting for climate and wildfire. After controlling for stream characteristics such as stream size, elevation, and stream slope, we demonstrate a positive response of riparian area vegetation to conservation-oriented grazing approaches and livestock exclosures, extensive beaver dam development, increased precipitation, and lack of wildfire. We show that livestock management which emphasizes riparian recovery objectives can be an important precursor to beaver activity and describe 11–39% increases in floodplain vegetation productivity where conservation-oriented grazing approaches or livestock exclosures and high beaver activity occur together on low-gradient sites. Land management decisions can therefore potentially confer resiliency to riparian areas under changing and variable climate conditions–the increased vegetation productivity resulting from conservation-oriented grazing or exclosures and high amounts of beaver activity at our sites is the equivalent to moving conventionally-grazed, low-gradient sites without beaver up at least 250 m in elevation or increasing water year precipitation by at least 250 mm.

If you build it, they will come: ranching, riparian revegetation, and beaver colonization in Elko County, Nevada

“…Several studies identify changes such as increased surface water, higher groundwater levels, improved stream conditions, and increased riparian vegetation that are at least partially attributable to the increase in beaver dams that has occurred in Elko County stream systems since the early 1990s. Additionally, research from Elko County and watersheds in southeastern Oregon documents the positive response of riparian vegetation along low-gradient streams to a combination of conservation grazing practices and beaver dam development, with benefits for fish and wildlife (Fesenmyer et al 2018). These documented changes are consistent with the observations of interviewees.…”

“…Some of these studies also documented the increase in beaver populations that accompanied these vegetation changes (table 2). As beaver colonize and build dams, they contribute to the vegetation recovery process (Fesenmyer et al 2018).…”

Remote sensing depicts riparian vegetation responses to water stress in a humid Atlantic region

“…In contrast, less documented are NDVI responses to climate variability, in humid and temperate regions, where water stress is an emerging threat (Gómez-Gener et al, 2020;Masante et al, 2018). In addition, previous studies have suggested that the major climatic factors affecting NDVI response may vary among climatic regions, riparian vegetation structure and management type (Huntington et al, 2016;Fesenmyer et al, 2018).…”

Changes in Meadow Phenology in Response to Grazing Management at Multiple Scales of Measurement

“…Understanding how groundwater dependent areas located within rangelands are affected by various management techniques is crucial to conservation. Their importance in arid and semi-arid ecosystems is generally disproportionate to their overall size [1,2]. Riparian areas boost landscape biodiversity [3], filter water [4], provide forage and water for livestock [5], and serve as suitable seasonal and year-round habitat for a wide variety of key taxa [6,7].…”