Michael R. Guttery

Effects of Landscape-Scale Environmental Variation on Greater Sage-Grouse Chick Survival

Effective long-term wildlife conservation planning for a species must be guided by information about population vital rates at multiple scales. Greater sage-grouse (Centrocercus urophasianus) populations declined substantially during the twentieth century, largely as a result of habitat loss and fragmentation. In addition to the importance of conserving large tracts of suitable habitat, successful conservation of this species will require detailed information about factors affecting vital rates at both the population and range-wide scales. Research has shown that sage-grouse population growth rates are particularly sensitive to hen and chick survival rates. While considerable information on hen survival exists, there is limited information about chick survival at the population level, and currently there are no published reports of factors affecting chick survival across large spatial and temporal scales. We analyzed greater sage-grouse chick survival rates from 2 geographically distinct populations across 9 years. The effects of 3 groups of related landscape-scale covariates (climate, drought, and phenology of vegetation greenness) were evaluated. Models with phenological change in greenness (NDVI) performed poorly, possibly due to highly variable production of forbs and grasses being masked by sagebrush canopy. The top drought model resulted in substantial improvement in model fit relative to the base model and indicated that chick survival was negatively associated with winter drought. Our overall top model included effects of chick age, hen age, minimum temperature in May, and precipitation in July. Our results provide important insights into the possible effects of climate variability on sage-grouse chick survival.

Evaluation of brood detection techniques: recommendations for estimating Greater Sage-Grouse productivity.

ABSTRACT. Obtaining timely and accurate assessment of sage-grouse (Centrocercus spp.) chick survival and recruitment is an important component of species management and conservation. We compared the effectiveness of walking, spotlight, and pointing-dog surveys to detect radio-marked and unmarked chicks within broods of radio-marked hens in Utah. Walking surveys detected 72% of marked chicks, while spotlight and pointing-dog surveys detected 100% and 96%, respectively. We found no difference between spotlight and pointing-dog counts in number of marked and unmarked chicks detected (P = 0.57). Spotlight counts were slightly more time efficient than pointing-dog surveys. However, spotlight surveys were nocturnal searches and perceived to be more technically arduous than diurnal pointing-dog surveys. Pointing-dog surveys may offer greater utility in terms of area searched per unit effort and an increased ability to detect unmarked hens and broods.

Effects of climatic variation and reproductive trade‐offs vary by measure of reproductive effort in greater sage‐grouse

Research on long-lived iteroparous species has shown that reproductive success may increase with age, until the onset of senescence, and that prior reproductive success may influence current reproductive success. Such complex reproductive dynamics can complicate conservation strategies, especially for harvested species. Further complicating the matter is the fact that most studies of reproductive costs are only able to evaluate a single measure of reproductive effort. We systematically evaluated the effects of climatic variation and reproductive trade-offs on multiple reproductive vital rates for greater sage-grouse (Centrocercus urophasianus; sage-grouse), a relatively long-lived galliforme of conservation concern throughout western North America. Based on over a decade of field observations, we hypothesized that reproduction is influenced by previous reproductive success. We monitored hen reproductive activity from 1998 to 2010, and used generalized linear mixed models to assess effects of climate and p...

Obtaining Adequate Light for Planted Bottomland Oak (Quercus spp.) Seedlings: A Case Study Utilizing Midstory Control

Bottomland hardwood forests of the United States have drastically declined since European settlement. Although much of the reported loss has resulted from conversion to agriculture and urban development, thousands of additional hectares have been degraded due to selective harvesting and a lack of effort to establish desirable regeneration prior to harvesting. Research has indicated that seedlings of some oak species perform best with intermediate levels of light, while performing less desirably at both high and low levels. This study demonstrates that controlling undesirable midstory trees through herbicide injection alone can be sufficient to create suitable light conditions for oak regeneration in some circumstances. We were able to increase the average percentage of total available light to 31.5% (SE = 0.029) as compared to only 14.2% (SE = 0.011) in untreated areas (F1,33 = 46.57, p < .0001). Additionally, oak seedlings planted in areas receiving midstory control exhibited good to excellent survival compared to results of other relevant studies. The present case study supports the belief that performance of oak seedlings can be increased by establishing appropriate light conditions.

Grassland bird productivity in warm season grass fields in southwest Wisconsin

Abstract Surrogate grasslands established through federal set-aside programs, such as U.S. Department of Agricultures Conservation Reserve Program (CRP), provide important habitat for grassland birds. Warm season grass CRP fields as a group have the potential for providing a continuum of habitat structure for breeding birds, depending on how the fields are managed and their floristic composition. We studied the nesting activity of four obligate grassland bird species, Bobolink (Dolichonyx oryzivorus), Eastern Meadowlark (Sturnella magna), Grasshopper Sparrow (Ammodramus savannarum), and Henslows Sparrow (A. henslowii), in relation to vegetative composition and fire management in warm season CRP fields in southwest Wisconsin during 2009–2011. Intraspecific variation in apparent nest density was related to the number of years since the field was burned. Apparent Grasshopper Sparrow nest density was highest in the breeding season immediately following spring burns, apparent Henslows Sparrow nest density was highest 1 y post burn, and apparent Bobolink and Eastern Meadowlark nest densities were higher in post fire years one to three. Grasshopper Sparrow nest density was highest on sites with more diverse vegetation, specifically prairie forbs, and on sites with shorter less dense vegetation. Bobolink, Eastern Meadowlark, and Henslows Sparrow apparent nest densities were higher on sites with deeper litter; litter was the vegetative component that was most affected by spring burns. Overall nest success was 0.487 for Bobolink (22 d nesting period), 0.478 for Eastern Meadowlark (25 d nesting period), 0.507 for Grasshopper Sparrow (22 d nesting period), and 0.151 for Henslows Sparrow (21 d nesting period). The major nest predators were grassland-associated species: thirteen-lined ground squirrel (Ictidomys tridecemlineatus), striped skunk (Mephitis mephitis), milk snake (Lampropeltis triangulum), American badger (Taxidea taxus), and western fox snake (Elaphe vulpina). Overall depredation rate was not affected by the number of years since the site had been burned. The diversity of vegetation on warm season CRP fields created by management using fire provides a continuum of structure for obligate grassland birds to use for breeding and habitat for a diversity of nest predators.