Grassland Conservation: An Integrative Approach

In an effort to integrate information from a wide range of data sets into a single spatially referenced grid that can be used to facilitate data discovery, and enhance research, personnel at the Kansas Biological Survey at the University of Kansas developed the Nested Hexagon Framework (NHF). The Nested Hexagon Framework is a response to the need for a spatial database to reference and summarize a wide range of datasets to help with data discovery and provide a more comprehensive (cross disciplinary) assessments of what characteristics are present at a given area.  The NHF can help inform preliminary site planning, environmental reviews, research endeavors, and make datasets more discoverable.  The NHF allows for the integration of local, regional, and national datasets, including wildlife observations, habitat models, land cover, land management, and more. The comprehensive nature of the datasets to be integrated and the subsequent ability to discover and share information not typically linked together is a unique and great opportunity to contribute to information sharing.

The NHF facilitates the sharing of useful information while keeping sensitive data private.  Having datasets pre-processed and readily available will make efforts more efficient and transparent, speed up environmental screenings, and promote interdisciplinary analysis and research.

Two recent projects have used the Nested Hexagon Framework in their effort to identify potential conservation priority areas for grassland species. The first project focused on the greater prairie chicken and sharp-tailed grouse as flagship species to develop a conservation strategy that would also benefit a host of tallgrass/mixedgrass prairie species. The second project sought to use prairie dog habitat suitability models, landscape variables, public opinion, and climate projections to identify conservation priorities areas for black-tailed prairie dogs. The map below shows the project footprints of efforts that have used the NHF.

Nested Hexagon Framework (NHF). Kansas Biological Survey and Center for Ecological Research. University of Kansas. Mike Houts, mhouts@ku.edu.

The NHF was used to assess a suite of landscape variables and delineate priority grassland areas for two important grassland bird species: the greater prairie-chicken (GPC) and the sharp-tailed grouse (STG).  

The overall goal of this effort was to develop a range-wide conservation strategy for greater prairie-chickens (GPC) and the plains and prairie subspecies of sharp-tailed grouse (STG) that will coordinate grassland and shrubland conservation efforts using these birds as flagship species. The long-term objective is to develop large blocks of native grasslands and shrublands of sufficient size, arrangement, and quality to support populations of GPC and STG and associated grassland and shrubland wildlife species.

• Delineate the estimated occupied range (EOR) for the GPC and STG
• Identify focal areas across that are sufficient in size to maintain viable populations.
• Identify additional species that will benefit from the grassland and shrubland conservation efforts designed for GPC and STG.
• Develop recommendations for policies, management priorities, and funding needed to effectively reverse population declines of prairie grouse and associated grassland species.
• Develop and recommend consistent monitoring approaches for GPC and STG.
• Develop an innovative habitat assessment tool for GPC and STG.

Species conservation depends upon knowing where that species is found. Traditional range maps are based upon the location of species' habitat at a broad scale. Many of these maps were created decades ago and are outdated Development, habitat destruction, and climate change have changed the distrubtion of many native species, and conservationists need current information about where species may live today. The Estimated Occupied Range (EOR) provides an updated, detailed map of where a species is expected to be found. The EOR's for the GPC and STG are based upon 1000's on-the-ground observations made by local experts across the species' range and are informed by the most current landcover maps based on remotely-sensed images (Figure 1).

We created EOR's for the greater prairie chicken (red dots) and Sharp-Tailed Grouse (blue dots) using a combination of observation data from state agencies and and data collected by citizen scientists using Ebird. Over 13,000 observations for Greater Prairie Chicken, and over 21,000 observations of sharp-tailed grouse were plotted to generate the EORs.

We drew a boundary line for the EOR for each species around the observation points (Figure 2). The highest quality habitat for Greater Prairie Chicken and Sharp-Tailed Grouse is in remote, roadless areas, making these areas less likely to be sampled. To account for this, we drew the boundary line loosely around the observation points. Using landcover patterns, aerial imagery, and other GIS layers, we interpolated habitat between occupied areas to determine if unoccupied areas were indeed potentially habitat. If unoccupied habitat appeared similar in composition to nearby occupied areas, the EOR was drawn to include those areas. As a generalized delineation, the EOR does includes areas of poor-quality GPC/STG habitat, particularly when located between two areas of higher-quality habitat.  Poor-quality habitats within the EOR could be good candidates for habitat improvement or restoration.

The creation of priority areas for GPC and STG is an important step towards a coordinated effort around rangewide population and habitat strategies. Each state developed their own priority areas, informed by the data sets that were intersected and summarized into the NHF. In instances where more (state specific) information was needed, states could summarize those layers using the grid and integrate them into the NHF to further assist the delineation. Additional datasets that were suggested include: state specific habitat probability models, existing or planned priority areas from other compatible causes, current conservation or management areas. Even with all this information available, expert opinions from people familiar with the region was important when identifying the particular cells to define each priority area.

When the priority area from each state were assembled together, a rangewide view of priority areas was created (Figure 3). Rangewide, priority areas submitted by Iowa, Minnesota, Nebraska, North Dakota, Oklahoma, South Dakota Wisconsin, cover a total of 178,071 km ² . The 208 priority areas had a mean size of 988 km ² , with the largest priority area being 52,401 km ²  in the Sandhills of Nebraska.

A key conclusion of this plan is that GPC and STG need a more concentrated delivery of conservation efforts into strategically located areas. A goal of establishing focal or core areas consisting of 50,000-acre blocks of high-quality habitat distributed across the range of each species was deemed essential to assure long term viability of each species. With this landscape being dominated by private "working lands" conservation efforts for these species must focus on engaging voluntary involvement of private landowners.

While a number of states participating in this effort have created priority areas, some states are still working on identifying priority areas and others are still working out how to use the areas. This plan recommends developing and utilizing a series of strategically located blocks of habitat areas to coordinate the targeting of grassland conservation efforts among grassland conservation initiatives

Using the data summarized into the NHF cells, queries can be done identiy areas with different types of needs (Figure 4). Areas with high levels of existing grassland would likely focus on delivery of conservation practices that would emphasize ranching methods to optimize GPC and STG habitat like prescribed grazing or prescribed burning practices. In areas where existing grasslands are limited due to conversions to agriculture, restoration methods, such as CRP may be emphasized along with a suite of ranching methods. In areas where woody encroachment is limiting habitat, tree/brush removal would be emphasized.

For additional information about the GPC and STG conservation strategy, contact Bill Van Pelt ( bill.vanpelt@wafwa.org)  WAFWA Grassland Coordinator.

In this project, the NHF was used to help identify and prioritize landscapes that could be targeted for the conservation of Black-Tailed Prairie Dogs now, and in the future as the global climate changes

Because prairie dogs function as ecosystem engineers and keystone species in North America’s grasslands, their conservation and management lies at the core of many conservation efforts.

Researchers created a habitat suitability model based on known locations of black-footed prairie dog colonies combined with data on 25 environmental variables such as annual precipitation, percent sand in the soil, and maximum temperature. In the model, darker green areas have highest habitat suitability, while beige areas have the lowest. The eastern edge of the range is limited by conversion of grasslands to cropland. Climate suitability limits prairie dog distribution on the southern edge.

Next, changes in prairie dog distribution was predicted under two different climate models, representing the best (warm, wet) and worse (hot, dry) case climate-change scenarios. In each case, suitable prairie dog habitat is lost in the southern part of the range, but is expected to expand northward as global temperatures increase. It will be tough going to prairie dogs in New Mexico and the Texas/Oklahoma panhandle region.

The final step was to identify priority areas of conservation efforts at the rangewid and state levels. The NHF was used to integrate current and future habitat suitability, favorable landscape conditions, and social willingness to conserve prairie dogs. In total input from 31 data layers were used included information on road density, oil/gas well density, and areas already under conservation. Results indicate that from a rangewide perspective, conservation priorities should be focused on the northern part of the black-tailed prairie dog range to account for the loss of habitat due to predicted climate change in the south . However, since there are currently prairie dog populations in the southern portion of the range that could be benefit from local conservation efforts, conservation priorites within each state were also examined.

For additional information about the black-tailed prairie dog project, contact Ana Davidsion ( Ana.Davidson@colostate.edu ) at Colorado State University, Colorado Natural Heritage Program, or Bill Van Pelt ( bill.vanpelt@wafwa.org)  WAFWA Grassland Coordinator.

The  Landscape Summary Database  (LSDB) is an additive database of information summarized by the cells of the NHF. Instead of endless columns of attributes conveying information for a cell, the LSDB is a PostgreSQL database that can store information from a wide range of datasets in one of its custom thematic attribute tables. As more information is summarized by the NHF grid and added into the LSDB, the depth of data readily available grows.

Reference your data to the NHF grid, its instantly compatible to all the other data sets summarized and integrated into the LSDB.

More information coming soon...

For additional information about the NHF, contact Mike Houts (mhouts@ku.edu) Kansas Biological Survey and Center for Ecological Research. University of Kansas