Greater sage‐grouse response to bentonite mining

Abstract

The greater sage-grouse (Centrocercus urophasianus; sage-grouse) has undergone range contraction and population decline because of anthropogenic land surface disturbances; yet, there is little information on the effects of mining on sage-grouse populations. In the Bighorn Basin of Montana and Wyoming, USA, bentonite mining is a growing source of surface disturbance that contributes to loss of sagebrush (Artemisia spp.) habitat. We evaluated the response of sage-grouse to active and reclaimed bentonite mining, relative to nesting, brood-rearing, adult breeding, and adult winter habitat, through resource selection and habitat-specific mortality risk analyses, based on female sage-grouse (n ¼ 321) monitored with telemetry from 2011-2015. A greater proportion of our monitored sample was exposed to mining disturbance during winter (65%) than during other seasons (range ¼ 25%-34%). We observed avoidance of all mining disturbance for selection of nesting habitat (n ¼ 378 nests), adult breeding habitat (n ¼ 1,978 locations), and adult winter habitat (n ¼ 1,365 locations). Evidence was inconclusive for avoidance of mining for brood-rearing habitat (n ¼ 754 locations). We also observed increased adult breeding season mortality risk (n ¼ 62 mortality events; n ¼ 285 female sage-grouse) associated with active mining disturbance but observed no effect on nest success (n ¼ 207 mortality events; n ¼ 378 nests). Evidence was inconclusive for increased mortality risk associated with broods (n ¼ 48 mortality events; n ¼ 157 broods) and adults during winter (n ¼ 31 mortality events; n ¼ 220 female sage-grouse). Stakeholders in the Bighorn Basin should be flexible and proactive to minimize the negative effects of bentonite mining on sage-grouse habitat use and demographic rates. Stakeholders should prioritize the conservation of winter habitats because of the influence on a greater proportion of the population and because of the lower regulatory priority given to winter habitat and they should strive to perfect mining reclamation to return disturbed sites back to pre-disturbance conditions to minimize long-term effects of the mines on sage-grouse. Ó 2019 The Wildlife Society.

Do greater sage‐grouse exhibit maladaptive habitat selection?

“…It appears that most evidence suggests that sage‐grouse react adaptively relative to high‐intensity disturbances such as oil and gas development and that these activities will not likely result in ecological traps because of grouse avoidance of these features. This conclusion is also consistent with a previous analysis in this study area that showed both higher mortality risk and increased avoidance associated with active bentonite mining (Pratt and Beck 2019). The one case of an apparent maladaptive selection relationship relative to selecting a disturbance that decreased survival was breeding adults selecting for proximity to minor roads where they were more likely to die, an example of a possible ecological trap.…”

“…Agricultural fields (row crops, hayfields, and pastures) were the most common disturbance and were located along the major floodplains. More detailed study area descriptions and figures are found in Pratt et al (2017) and Pratt and Beck (2019).…”

“…During 2011-2015, we captured, aged (yearling or adult; Eng 1955), and marked female sage-grouse with very-high frequency (VHF) radio transmitters (22-g necklace-mounted VHF transmitter Model A4060, Advanced Telemetry Systems, Isanti, Minnesota, USA) or with Global Positioning System (GPS) equipped Platform Transmitter Terminals (22-g Solar Argos/GPS PTT-100, Microwave Telemetry, Columbia, Maryland, USA or Model 22 GPS PTT, North Star Science and Technology, King George, Virginia, USA). We collected grouse locations according to season and monitored survival and reproductive success according to established protocols described in Pratt et al (2017) and Pratt and Beck (2019). Sage-grouse capture and monitoring were approved by University of Wyoming Animal Care and Use Committee (protocols 03142011 and 20140228JB00065) and were completed under permits from Wyoming Game and Fish Department (Chapter 33 Permit 800) and Montana Fish, Wildlife and Parks (Scientific Collector's Permits 2013-072, 2014-037, and 2015-76).…”

“…We defined breeding season survival as the probability of an adult surviving 89 d, summer survival as the probability over 89 d, and winter survival as the probability over 127 d which were the median season lengths observed in our study area (Pratt 2017). We defined nest survival as at least 1 egg hatching after 26.5 d of incubation, and we defined brood survival as at least 1 chick surviving to 35 d posthatch, which coincided with our field brood counts (Pratt and Beck 2019). We estimated these vital rates according to grouse use of a specific seasonal habitat characteristic by adding the variable in question to the final mortality-risk models.…”

“…However, if sage-grouse populations are influenced by ecological and perceptual traps, then there is a greater risk of population decline than what may be realized. Significant threats of habitat loss and fragmentation to sage-grouse are from land surface disturbances such as agricultural development (e.g., Smith et al 2016), energy development (e.g., Kirol et al 2015), mineral development (e.g., Pratt and Beck 2019), residential development (Connelly et al 2004), livestock grazing (e.g., Beck and Mitchell 2000), and fire (e.g., Lockyer et al 2015). Sage-grouse is a species with strong habitat selection tendencies relative to environmental and anthropogenic landscape features, which also influences its survival.…”