Patterns and dynamics of vegetation recovery following grazing cessation in the California golden trout habitat

Sébastien Nusslé,Stephanie M Carlson,Kathleen R Matthews

doi:10.1002/ecs2.1880

Sébastien Nusslé, Stephanie M Carlson + Show 1 more

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https://doi.org/10.1002/ecs2.1880

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Abstract

AbstractIn 1978, the Golden Trout Wilderness area was established to protect the California golden trout (Oncorhynchus mykiss aguabonita)—a vulnerable subspecies of the rainbow trout that is endemic to California—and its habitat, which is currently restricted to a few streams within high‐elevation meadows in the Sierra Nevada Mountain Range. Because of the deleterious effects of livestock grazing on riparian vegetation in the golden trout habitat (occurring since the 1800s), meadow restoration activities were initiated in 1991, including cattle exclusion. There has been renewed discussion about re‐opening these public lands to livestock grazing, and impact assessment studies are needed to inform decision makers about the potential consequences. Thus, we estimated the recovery potential of the golden trout habitat by measuring the height of riparian vegetation within areas that have been grazed vs. closed to grazing (“rested”) since 1991. We found that cattle exclusion is effective at favoring riparian vegetation growth, but that vegetation recovery from grazing could take several decades in these sensitive habitats as some “rested” areas have yet to recover to full vegetation height, even after 25 yr of rest.

Highlights

Humans dominate the earth’s ecosystems (Vitousek et al 1997) and have radically altered land surfaces and land use, thereby triggering increased pressure on the environment (Foley et al 2005)
We found that reduced vegetation due to the combined effects of cattle activities can lead to river temperatures over 5°C higher in areas where cattle are present compared to ungrazed areas, where vegetation was both denser and larger due to cattle exclusion since 1991 (Nussle et al 2015)
These results indicate that recovering after cattle exclusion, that is, attaining maximum willow height, can take over a decade

Summary

Introduction

Humans dominate the earth’s ecosystems (Vitousek et al 1997) and have radically altered land surfaces and land use, thereby triggering increased pressure on the environment (Foley et al 2005). Some land-use activities, such as livestock grazing and crop farming, have legacy effects that may influence ecosystem structure and functioning for decades, even after their cessation (Foster et al 2003). One common land-use practice of growing concern is livestock grazing (Milchunas and Lauenroth 1993, Foster et al 2003, Agouridis et al 2005). As the demand for livestock follows the increased consumption of animal protein by humans in developed countries (Gill 1999), so does its consequences in terms of pressure on the environment (McMichael et al 2007). Many concerns have been raised with regard to the negative effects of livestock grazing on terrestrial and freshwater ecosystems (Belsky 1987, Fleischner 1994)

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