Prioritizing healthy grasslands leads to more efficient conservation than focusing solely on wildlife

Conserving ecosystems provides better conservation outcomes for imperiled species more efficiently than single-species conservation efforts.

Rallying around wildlife species like the greater sage-grouse helped shape win-win voluntary conservation work across western North America’s sagebrush and grassland landscapes. New research, supported by Working Lands for Wildlife, now shows that prioritizing intact landscapes results in more effective and efficient conservation than focusing on a single wildlife species.

Decisions on how to manage ecosystems and allocate resources have historically relied on one species to inform and drive conservation objectives. In this approach, one key species—like greater sage-grouse—serves as a surrogate, or representative, for the health of other wildlife or other aspects of the environment. The assumption was that, if properly chosen, the resources directed towards this species would extend benefits to the broader community of organisms within its ecosystem. By many metrics, this method has been successful and, in the case of greater sage-grouse, has indeed helped to improve rangeland health, habitat quality, and quality of life across the sagebrush biome. Expanding the efficacy of conservation work, however, requires widening the lens from a single critter—and their specific habitat needs—to a full suite of wildlife species, along with other ecosystem services and rural community values.

Jason Tack, a wildlife biologist with the U.S. Fish and Wildlife Service, wanted to evaluate how measures of habitat intactness–derived entirely from remotely sensed vegetation data –compared to the old model of single species surrogacy. To do this, Tack and his team developed a way to test the “strength of surrogacy” of both approaches using the data-rich grasslands of the Montana Hi-Line and southern Canada as a stage.

First, Tack’s team gathered previously developed maps that predicted important ecological metrics, like habitat selection and relative abundance, for several species commonly used in the region’s conservation planning, namely greater sage-grouse, Sprague’s pipit, pronghorn, and a selection of grassland-nesting ducks. Tack then evaluated models for these individual species alongside two non-single species models—one focused on critical areas for connectivity and one based simply on habitat intactness. This allowed Tack to see which models could be relied on as strong surrogates for underlying habitat requirements and would therefore be most effective in benefiting the broader wildlife community.

Tack’s results found that while all but one of the single-species models showed positive strength of surrogacy, as the spatial scale increased, the model of intactness outcompeted any of those focused on a single critter or even the connectivity model. The simplest measure was the best—landscape intactness outperformed all single species models and provided the best overall predictor of underlying species needs, especially at large scales needed for landscape conservation. In short, this research highlights the benefits of prioritizing the “stage” over the individual “actors.”

Tack’s research comes at a crucial time as advancements in remote sensing tools put spatial technologies at the forefront of many emerging conservation designs. These results provide real-world insight into the previously untested question of whether remotely-sensed “core areas” can meet the needs of species’ underlying biome-specific requirements and ultimately add to the growing evidence for “Defend the Core” as a highly effective strategy for achieving conservation outcomes at a landscape scale. Evaluating biodiversity and monitoring wildlife populations is still important, but working in concert with other ecosystem services like water quantity and quality, forage availability, and connectivity elevates this work from a small stage to a biome-sized one. Placing intact landscapes at the center of conservation frameworks provides a scalable, science-based strategy that brings in everyone who lives in, works on, and values these landscapes.

Tack’s science bolsters the shift in strategy by the western Working Lands for Wildlife team to expand from species-focused work under the Sage Grouse Initiative to the Framework for Conservation Action in the Sagebrush Biome. This action-based framework provides a common vision and coordination to address resource concerns and ecosystem threats across boundaries. This ability to plan and preserve more effective conservation on working lands fortifies the resiliency of not only wildlife species, but also rural communities, economies, and cultures for generations to come.

GRASSLAND INTACTNESS OUTCOMPETES SPECIES AS A MORE EFFICIENT SURROGATE IN CONSERVATION DESIGN

Abstract: Mapped representations of species−habitat relationships often underlie approaches to prioritize area-based conservation strategies to meet conservation goals for biodiversity. Generally a single surrogate species is used to inform conservation design, with the assumption that conservation actions for an appropriately selected species will confer benefits to a broader community of organisms.

Emerging conservation frameworks across western North America are now relying on derived measures of intactness from remotely sensed vegetation data, wholly independent from species data. Understanding the efficacy of species-agnostic planning approaches is a critical step to ensuring the robustness of emerging conservation designs. We developed an approach to quantify ‘strength of surrogacy’, by applying prioritization algorithms to previously developed species models, and measuring their coverage provided to a broader wildlife community.

We used this inference to test the relative surrogacy among a suite of species models used for conservation targeting in the endangered grasslands of the Northern Sagebrush Steppe, where careful planning can help stem the loss of private grazing lands to cultivation. In this test, we also derived a simpler surrogate of intact rangelands without species data for conservation targeting, along with a measure of combined migration representative of key areas for connectivity.

Our measure of intactness vastly outperformed any species model as a surrogate for conservation, followed by that of combined migration, highlighting the efficacy of strategies that target large and intact rangeland cores for wildlife conservation and restoration efforts.

Citation: Tack, J. D., Jakes, A. F., Jones, P. F., Hebblewhite, M., Naugle, D. E., Doherty, K. E., Sather, M. K., Martin, B. H., & Pritchert, R. (2023). Grassland intactness outcompetes species as a more efficient surrogate in conservation design. Conservation Science and Practice, e13020.

Permanent URL: https://doi.org/10.1111/csp2.13020

Acknowledgements: Funding for this project was provided by the Alberta Conservation Association, National Fish and Wildlife Foundation, and Sagebrush Science Initiative (a collaboration between the U.S. Fish and Wildlife Services and Western Association of Fish and Wildlife Agencies). Findings and conclusions in this article are those of the authors and do not necessarily represent the views of the U.S. Fish and Wildlife Service.