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Martha J. Desmond

Bio: Martha J. Desmond is an academic researcher from New Mexico State University. The author has contributed to research in topics: Nest & Ecology. The author has an hindex of 10, co-authored 20 publications receiving 406 citations.

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Journal ArticleDOI
TL;DR: Efforts are needed to ensure preservation of black-tailed prairie dog colonies for burrowing owls and other species associated with this prairie ecosystem, and to better monitor changes in burrowing owl and prairieDog populations.
Abstract: Concern over the status of species associated with prairie dog colonies has increased with the recent proposed listing of black-tailed prairie dogs (Cynomys ludovicianus). We monitored burrowing owl (Athene cunicularia) populations and prairie dog densities in 17 black-tailed prairie dog colonies in the Nebraska panhandle between 1990 and 1996. All prairie dog colonies were controlled at least once during the study. We observed a 63% decline in nesting pairs of burrowing owls and significant declines in burrow densities. Results indicated a time lag in owl response to changes in active burrow densities. However, in the later years of the study when burrow densities were lowest, owl numbers were positively correlated with the density of active burrows in the same years, indicating active burrows may become more important as burrow density declines. We also monitored fledging success of burrowing owls for 398 nesting attempts over 5 years (1989-93) for a larger set of colonies that included the 17 used in the owl and prairie dog monitoring. Differences in mean fledging success among colonies each year (colony effect) explained most of the variation in fledging success among nesting owls. Vulnerability to badger (Taxidea taxus) predation may in part explain differences in fledging success among colonies; badger predation on owl nests was lower when densities of active prairie dog burrows were high. Efforts are needed to ensure preservation of black-tailed prairie dog colonies for burrowing owls and other species associated with this prairie ecosystem, and to better monitor changes in burrowing owl and prairie dog populations.

131 citations

Journal ArticleDOI
TL;DR: As the size of prairie dog towns increased, burrowing owls occurred in higher numbers but lower densities, andBurrow availability may be a limiting factor for owls nesting in pastures with badger burrows.
Abstract: -Burrowing owls (Speotyto cunicularia) were studied at 21 prairie dog towns in native prairie and 17 native prairie pastures with badger (Taxidea taxus) burrows in the Nebraska panhandle in the spring and summer from 1989-1991. The number of nesting burrowing owl pairs ranged from 1-20 in prairie dog (Cynomys ludovicianus) towns and from 1-4 in pastures with badger burrows. Burrowing owl densities in small prairie dog towns ( 35 ha) prairie dog towns ranged from 0.9-2.5 owls/ha. Mean nearest-neighbor distance (?SE) in clusters within large (?35 ha) prairie dog towns was 125.0 m + 4.6, whereas the mean distance between owl nests in small towns (<35 ha), where owls did not have the space to cluster, was 105.1 m + 7.4. Mean nearest-neighbor distance for owls nesting in pastures with badger burrows was 240.2 m ? 39.2. No relationship was found between owl numbers and number of active or inactive prairie dog burrows. In 1990 burrowing owl density was inversely related to active burrow density, but no relationship was found in 1991. Burrow availability may be a limiting factor for owls nesting in pastures with badger burrows. As the size (ha) of prairie dog towns increased, burrowing owls occurred in higher numbers but lower densities.

64 citations

Journal ArticleDOI
TL;DR: The spatial patterns of burrowing owl nests in black-tailed prairie dog towns were examined in the Nebraska panhandle during the spring and summer of 1989–1991 and it was not possible for owls to demonstrate patterns other than random in the smaller towns, but choice of nest sites by pairs resulted in a clumped nest distribution.
Abstract: The spatial patterns of burrowing owl (Speotyto cunicularia) nests in black-tailed prairie dog (Cynomys ludovicianus) towns were examined in the Nebraska panhandle during the spring and summer of 1989–1991. Because of higher nest densities (≥ 0.20 nests/ha) and internest distance requirements, it was not possible for owls to demonstrate patterns other than random in the smaller ( 35 ha), burrowing owls were less dense (≤ 0.20 nests/ha), and choice of nest sites by pairs resulted in a clumped nest distribution. In prairie dog towns < 35 ha, nearest neighbor distance was positively related to prairie dog town size, whereas no relationship was found between prairie dog town size and nearest neighbor distance for towns ≥ 35 ha. Burrow availability was not responsible for clumping. Ample burrows were available throughout the towns in 1990 and 1991. In 1991, two towns with clumped distributions of owls showed no differences in numbers of burrows around ac...

47 citations

Journal ArticleDOI
TL;DR: Higher nest success, but fewer fledglings per successful nest, suggests competition for resources in this habitat, and high success in grassland habitats was associated with fewer surrounding nests, index of larger nesting territories, edge nests, and lower fledgling success of the nearest nest.
Abstract: We examined Burrowing Owl (Athene cunicuaria) reproductive success at 144 nests in urban (n = 80) and grassland (n = 64) habitats in southern New Mexico in 2000 and 2001. Nest success was higher in grassland compared to urban areas (81 vs. 68%) but urban landscapes fledged more young per successful nest (3.85 vs. 3.07). Mean fledging success per nest was similar between habitats with 2.60 and 2.50 fledglings in urban and grassland habitats, respectively. Fledging success was categorized as failure, low, and high. Reproductive success in both habitats was associated with measures of owl density. High success in urban landscapes was associated with fewer surrounding nests, an index of larger nesting territories, and open space. Failure was associated with solitary nests. This suggests owls benefit from the presence of other nesting pairs as long as the density is not too high. High success in grassland habitats was associated with fewer surrounding nests, index of larger nesting territories, ed...

38 citations

Journal ArticleDOI
TL;DR: In this paper, the Janos-Nuevo Casas Grandes black-tailed prairie dog (Cynomys ludovicianus) complex in northwestern Chihuahua, Mexico, an area containing 58 colonies with 30,000 ha of prairie dogs.

32 citations


Cited by
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Journal Article
TL;DR: In this paper, a test based on two conserved CHD (chromo-helicase-DNA-binding) genes that are located on the avian sex chromosomes of all birds, with the possible exception of the ratites (ostriches, etc.).

2,554 citations

Journal ArticleDOI

556 citations

Book ChapterDOI
01 Jan 2017
TL;DR: In this article, the authors review the process of woody plant encroachment and its causes, the consequences for ecosystem function and the provision of services, and the effectiveness of management interventions aimed at reducing woody cover.
Abstract: Woody vegetation in grasslands and savannas has increased worldwide over the past 100–200 years. This phenomenon of “woody plant encroachment” (WPE) has been documented to occur at different times but at comparable rates in rangelands of the Americas, Australia, and southern Africa. The objectives of this chapter are to review (1) the process of WPE and its causes, (2) consequences for ecosystem function and the provision of services, and (3) the effectiveness of management interventions aimed at reducing woody cover. Explanations for WPE require consideration of multiple interacting drivers and constraints and their variation through time at a given site. Mean annual precipitation sets an upper limit to woody plant cover, but local patterns of disturbance (fire, browsing) and soil properties (texture, depth) prevent the realization of this potential. In the absence of these constraints, seasonality, interannual variation, and intensity of precipitation events determine the rate and extent of woody plant expansion. Although probably not a triggering factor, rising atmospheric CO2 levels may have favored C3 woody plant growth. WPE coincided with the global intensification of livestock grazing that by reducing fine fuels, hence fire frequency and intensity, facilitated WPE. From a conservation perspective, WPE threatens the maintenance of grassland and savanna ecosystems and its endemic biodiversity. Traditional management goals aimed at restoring forage and livestock production after WPE have broadened to support a more diverse portfolio of ecosystem services. Accordingly, we focus on how WPE and management actions aimed at reducing woody plant cover influence carbon sequestration, water yield, and biodiversity, and discuss the trade-offs involved when balancing competing management objectives.

349 citations

Journal ArticleDOI
TL;DR: It is confirmed that prairie dogs affect a number of ecosystem-level functions but that their influence on prairie vertebrates may be less than previously suggested, and some prairie dog functions are quite large compared to other herbivores in the system.
Abstract: spp.) have been labeled as keystone species because of their influence on biological diversity and ecosystem function. However, the validity of several assumptions used to support keystone status is questionable. We review the strength of the evidence and the magnitude of the prairie dog's effects on ecosystem structure and function. We use this review to reevaluate the keystone role for prairie dogs. Our goal is to encourage sound management of the prairie dog ecosystem by improving the ecological foundation of their keystone status. Our review confirms that prairie dogs affect a number of ecosystem-level functions but that their influence on prairie vertebrates may be less than previously suggested. Species richness and abundance patterns were variable among plants, mammals, and birds and were not consistently higher on prairie dog colonies compared to uncolonized areas. In addition, only nine of the 208 species listed in the literature as observed on or near prairie dogs colonies had quantitative evidence of dependence on prairie dogs. Abundance data indicated opportunistic use of colonies for an additional 20 species. A total of 117 species may have some relationship with prairie dogs, but we lacked sufficient data to evaluate the strength of this relationship. The remaining 62 species may be accidental or alien to the system. Despite our conclusion that some prairie dog functions may be smaller than previously assumed, collectively these functions are quite large compared to other herbivores in the system. We suggest that prairie dogs also provide some unique functions not duplicated by any other species and that continued decline of prairie dogs may lead to a substantial erosion of biological diversity and landscape heterogeneity across prairie and shrub-steppe landscapes. Thus, we concur that keystone status for prairie dogs is appropriate and may aid conservation efforts that help protect species dependent on prairie dogs and support other important ecosystem functions.

252 citations