Modeling Songbird Density-Habitat Relationships to Predict Population Responses to Environmental Change Within Pinyon-juniper and Sagebrush Ecosystems Active
Within areas of overlapping sagebrush and pinyon-juniper ecosystems, wildlife populations are declining due to habitat fragmentation and degradation, changing climate, and human development. However, management to bolster species associated with one ecosystem may result in negative consequences for species associated with the other. Thus, land managers are challenged with balancing which system to manage for and where to maintain ecological function within and across these systems.
To address this challenge, we are developing density-habitat relationship and trend models for 12 songbird species which use sagebrush ecosystems and/or pinyon-juniper woodlands. These models should assist land managers in identifying priority species, evaluating environmental impacts of management actions, selecting appropriate place-based management actions, and targeting areas for restoration.
Background
Effective wildlife management requires detailed information regarding population status, habitat requirements, and likely responses to changing resource conditions. Single-species management may inadequately conserve communities and result in undesired effects to non-target species. Thus, management can benefit from understanding habitat relationships for multiple species within, and across, ecosystems. Pinyon pine (Pinus edulis and Pinus monophylla) and juniper (Juniperus spp.) trees have expanded into regions dominated by sagebrush over the last 50+ years within western North America, and mechanical removal of these trees is frequently implemented to restore sagebrush ecosystems (Figure 1). Mechanical conifer removal has proven effective for enhancing greater sage-grouse (Centrocercus urophasianus; hereafter, “sage-grouse”) populations and habitat. Unfortunately, conifer removal may have negative effects for non-target species, and a changing climate and anthropogenic development may further obscure conservation priorities.
Project Objectives
- Model population trends and relationships between species’ density and environmental features (hereafter, “density-habitat relationships”) for four sagebrush-associated, five pinyon-juniper-associated, and three generalist songbird species across much of the western United States.
- Evaluate the population model outputs to assess the potential consequences of a changing climate, landcover conversion, land management practices, and anthropogenic development.
- Use the modeled relationships to predict songbird population density across the landscape.
Anticipated Benefits to Decision-Making in Resource Management
- Modeled density-habitat relationships can be used to predict species responses to changing resource conditions, helping managers prioritize species for conservation action which may be increasingly at-risk in the future.
- Information from this study can help managers anticipate effects of conifer removal practices on non-target species, and be incorporated into environmental impact assessments.
- Managers can evaluate regional population trends and use that information to prioritize species for conservation.
- Density-habitat relationships can provide guidance regarding what environmental features managers may wish to increase or decrease so the landscape may support higher densities of priority species within the sagebrush and pinyon-juniper ecosystems.
Approach
We are using breeding season point count data from the Integrated Monitoring in Bird Conservation Regions program collected from 2008 – 2020 to model songbird population density-habitat relationships. Our model includes regional population trends, anthropogenic disturbance layers, vegetation cover, topographic, and climatic variables. We are then using high performance computing to predict songbird population density for each species across much of the western United States at 30m resolution, given environmental conditions from 2020.
Scientific findings
We modeled pinyon jay (Gymnorhinus cyanocephalus) population trends and habitat associations to identify (1) where populations are stable or declining, (2) identify environmental characteristics which support high jay densities, and (3) inform population recovery efforts. We found conifer removal to restore sagebrush ecosystems may reduce jay populations where they occur. Additionally, we identified regions where pinyon jays have declined since 2008 (Figure 2) so managers can prioritize stabilizing these populations. Our density-habitat relationships for pinyon jays indicated they use early successional pinyon-juniper forests, characterized by both sagebrush and pinyon-juniper cover (Figure 3). Unfortunately, most conifer removal efforts to recover sage-grouse habitat occur within these early successional pinyon-juniper woodlands.
Implications
Our model results can be used to quantify expected jay gains and losses to environmental perturbations to inform impact assessments and restoration activities within the sagebrush and pinyon-juniper ecosystems. Our maps of predicted jay densities (Figure 4) can help managers target sites for conifer removal where there are few to no jays expected. Our density-habitat relationship model for pinyon jay can also help quantify expected jay gains and losses which are likely to result from conifer removal, and other restoration activities, within the sagebrush and pinyon-juniper ecosystems.
Next steps
We are finalizing density-habitat relationship models for the 11 other songbird species and applying these density-habitat relationships to prioritize sites for conifer removal which are predicted to maximize population gains for multiple sagebrush-associated species while minimizing potential negative effects for several pinyon-juniper-associated species.
Prioritizing Restoration of Sagebrush Ecosystems Tool (PReSET): A USGS-facilitated Decision-support Tool for Sagebrush Ecosystem Conservation and Restoration Actions
The Wyoming Landscape Conservation Initiative (WLCI)
Within areas of overlapping sagebrush and pinyon-juniper ecosystems, wildlife populations are declining due to habitat fragmentation and degradation, changing climate, and human development. However, management to bolster species associated with one ecosystem may result in negative consequences for species associated with the other. Thus, land managers are challenged with balancing which system to manage for and where to maintain ecological function within and across these systems.
To address this challenge, we are developing density-habitat relationship and trend models for 12 songbird species which use sagebrush ecosystems and/or pinyon-juniper woodlands. These models should assist land managers in identifying priority species, evaluating environmental impacts of management actions, selecting appropriate place-based management actions, and targeting areas for restoration.
Background
Effective wildlife management requires detailed information regarding population status, habitat requirements, and likely responses to changing resource conditions. Single-species management may inadequately conserve communities and result in undesired effects to non-target species. Thus, management can benefit from understanding habitat relationships for multiple species within, and across, ecosystems. Pinyon pine (Pinus edulis and Pinus monophylla) and juniper (Juniperus spp.) trees have expanded into regions dominated by sagebrush over the last 50+ years within western North America, and mechanical removal of these trees is frequently implemented to restore sagebrush ecosystems (Figure 1). Mechanical conifer removal has proven effective for enhancing greater sage-grouse (Centrocercus urophasianus; hereafter, “sage-grouse”) populations and habitat. Unfortunately, conifer removal may have negative effects for non-target species, and a changing climate and anthropogenic development may further obscure conservation priorities.
Project Objectives
- Model population trends and relationships between species’ density and environmental features (hereafter, “density-habitat relationships”) for four sagebrush-associated, five pinyon-juniper-associated, and three generalist songbird species across much of the western United States.
- Evaluate the population model outputs to assess the potential consequences of a changing climate, landcover conversion, land management practices, and anthropogenic development.
- Use the modeled relationships to predict songbird population density across the landscape.
Anticipated Benefits to Decision-Making in Resource Management
- Modeled density-habitat relationships can be used to predict species responses to changing resource conditions, helping managers prioritize species for conservation action which may be increasingly at-risk in the future.
- Information from this study can help managers anticipate effects of conifer removal practices on non-target species, and be incorporated into environmental impact assessments.
- Managers can evaluate regional population trends and use that information to prioritize species for conservation.
- Density-habitat relationships can provide guidance regarding what environmental features managers may wish to increase or decrease so the landscape may support higher densities of priority species within the sagebrush and pinyon-juniper ecosystems.
Approach
We are using breeding season point count data from the Integrated Monitoring in Bird Conservation Regions program collected from 2008 – 2020 to model songbird population density-habitat relationships. Our model includes regional population trends, anthropogenic disturbance layers, vegetation cover, topographic, and climatic variables. We are then using high performance computing to predict songbird population density for each species across much of the western United States at 30m resolution, given environmental conditions from 2020.
Scientific findings
We modeled pinyon jay (Gymnorhinus cyanocephalus) population trends and habitat associations to identify (1) where populations are stable or declining, (2) identify environmental characteristics which support high jay densities, and (3) inform population recovery efforts. We found conifer removal to restore sagebrush ecosystems may reduce jay populations where they occur. Additionally, we identified regions where pinyon jays have declined since 2008 (Figure 2) so managers can prioritize stabilizing these populations. Our density-habitat relationships for pinyon jays indicated they use early successional pinyon-juniper forests, characterized by both sagebrush and pinyon-juniper cover (Figure 3). Unfortunately, most conifer removal efforts to recover sage-grouse habitat occur within these early successional pinyon-juniper woodlands.
Implications
Our model results can be used to quantify expected jay gains and losses to environmental perturbations to inform impact assessments and restoration activities within the sagebrush and pinyon-juniper ecosystems. Our maps of predicted jay densities (Figure 4) can help managers target sites for conifer removal where there are few to no jays expected. Our density-habitat relationship model for pinyon jay can also help quantify expected jay gains and losses which are likely to result from conifer removal, and other restoration activities, within the sagebrush and pinyon-juniper ecosystems.
Next steps
We are finalizing density-habitat relationship models for the 11 other songbird species and applying these density-habitat relationships to prioritize sites for conifer removal which are predicted to maximize population gains for multiple sagebrush-associated species while minimizing potential negative effects for several pinyon-juniper-associated species.