Abstract
Functional connectivity, quantified using landscape genetics, can inform conservation through the identification of factors linking genetic structure to landscape mechanisms. We used breeding habitat metrics, landscape attributes, and indices of grouse abundance, to compare fit between structural connectivity and genetic differentiation within five long-established Sage-Grouse Management Zones (MZ) I-V using microsatellite genotypes from 6,844 greater sage-grouse (Centrocercus urophasianus) collected across their 10.7 million-km2 range. We estimated structural connectivity using a circuit theory-based approach where we built resistance surfaces using thresholds dividing the landscape into “habitat” and “nonhabitat” and nodes were clusters of sage-grouse leks (where feather samples were collected using noninvasive techniques). As hypothesized, MZ-specific habitat metrics were the best predictors of differentiation. To our surprise, inclusion of grouse abundance-corrected indices did not greatly improve model fit in most MZs. Functional connectivity of breeding habitat was reduced when probability of lek occurrence dropped below 0.25 (MZs I, IV) and 0.5 (II), thresholds lower than those previously identified as required for the formation of breeding leks, which suggests that individuals are willing to travel through undesirable habitat. The individual MZ landscape results suggested terrain roughness and steepness shaped functional connectivity across all MZs. Across respective MZs, sagebrush availability (<10%–30%; II, IV, V), tree canopy cover (>10%; I, II, IV), and cultivation (>25%; I, II, IV, V) each reduced movement beyond their respective thresholds. Model validations confirmed variation in predictive ability across MZs with top resistance surfaces better predicting gene flow than geographic distance alone, especially in cases of low and high differentiation among lek groups. The resultant resistance maps we produced spatially depict the strength and redundancy of range-wide gene flow and can help direct conservation actions to maintain and restore functional connectivity for sage-grouse.
| Original language | English |
|---|---|
| Pages (from-to) | 1305-1321 |
| Number of pages | 17 |
| Journal | Evolutionary Applications |
| Volume | 11 |
| Issue number | 8 |
| DOIs | |
| State | Published - Sep 2018 |
Funding
state, federal, and nongovernmental organization (NGO) biologists and technicians who have spent lifetimes working tirelessly in the field and behind desks for the conservation of the greater sage-grouse. We specifically acknowledge field biologists and technicians with the Bureau of Land Management, California Department of Fish & Game, Colorado Division of Wildlife, Idaho Fish & Game, Montana Fish, Wildlife & Parks, Montana Audubon, Nevada Division of Wildlife, North Dakota Game and Fish, Natural Resources Conservation Service: Sage-Grouse Initiative, Oregon Fish & Wildlife, South Dakota Game, Fish & Parks, Utah Wildlife Resources, U.S. Forest Service (USFS), Washington Department of Fish and Wildlife, and Wyoming Game & Fish Department. We acknowledge the support of the Natural Sciences and Engineering Research Council of Canada (NSERC) to BF (funding reference number 50503-10694). Our molecular genetics analyses and manuscript preparation would not have been possible without Cory Engkjer, Kevin McKelvey, and Kristy Pilgrim, with laboratory work by Kara Bates, Nasreen Broomand, Taylor Dowell, Jennifer Fike, Scott Hampton, Randi Lesagonicz, Inga Ortloff, Sara Schwarz, Kate Welch, the USFS Rocky Mountain Research Station National Genomics Center for Wildlife and Fish Conservation, and the USGS FORT Molecular This research would not have been possible without the many state, federal, and non- governmental organization (NGO) biologists and technicians who have spent lifetimes working tirelessly in the field and behind desks for the conservation of the greater sage-grouse. We specifically acknowledge field biologists and technicians with the Bureau of Land Management, California Department of Fish & Game, Colorado Division of Wildlife, Idaho Fish & Game, Montana Fish, Wildlife & Parks, Montana Audubon, Nevada Division of Wildlife, North Dakota Game and Fish, Natural Resources Conservation Service: Sage-Grouse Initiative, Oregon Fish & Wildlife, South Dakota Game, Fish & Parks, Utah Wildlife Resources, U.S. Forest Service (USFS), Washington Department of Fish and Wildlife, and Wyoming Game & Fish Department. We acknowledge the support of the Natural Sciences and Engineering Research Council of Canada (NSERC) to BF (funding reference number 50503-10694). Our molecular genetics analyses and manuscript preparation would not have been possible without Cory Engkjer, Kevin McKelvey, and Kristy Pilgrim, with laboratory work by Kara Bates, Nasreen Broomand, Taylor Dowell, Jennifer Fike, Scott Hampton, Randi Lesagonicz, Inga Ortloff, Sara Schwarz, Kate Welch, the USFS Rocky Mountain Research Station National Genomics Center for Wildlife and Fish Conservation, and the USGS FORT Molecular Ecology Laboratory. This draft manuscript is distributed solely for purposes of scientific peer review. Its content is deliberative and predecisional, so it must not be disclosed or released by reviewers. Because the manuscript has not yet been approved for publication by the U.S. Geological Survey (USGS), it does not represent any official USGS finding or policy. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. The 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.
| Funders | Funder number |
|---|---|
| Oregon Department of Fish and Wildlife | |
| California Department of Fish and Wildlife | |
| U.S. Forest Service-Retired | |
| Bureau of Land Management | |
| Alaska Department of Fish and Game | |
| Utah Division of Wildlife Resources | |
| 50503-10694 |
Keywords
- dispersal
- gene flow
- genetic differentiation
- genetic diversity
- habitat selection models
- isolation by resistance
- landscape resistance