Impacts of nonnative plant species on production and diversity in the front range of Colorado

Nonnative plant species are considered one of the greatest threats to biodiversity, yet we still are unable to predict how production and diversity of a community will change once a species has invaded. Ponderosa pine woodlands in the Front Range of Colorado are ideal for studying the impacts of nonnative plants on production and species richness. We selected 5 sites along the northern Front Range with varying proportions of nonnative and native species and compared understory production and species richness along the gradient of nonnative species dominance. Total species production was positively and significantly related to total species richness, and total species production increased significantly with increasing nonnative species richness. There was a negative relationship between native and nonnative species production, and there was no relationship between nonnative species richness and native species richness. This study demonstrates the complex nature of species richness and productivity relationships and should serve as a starting point for future research in which a variety of other variables are considered.     

White-Tailed Prairie Dog ( Cynomys leucurus Merriam) Diggings in Western Harvester Ant, Pogonomyrmex occidentalis (Cresson), Mounds

We report observations of the white-tailed prairie dog, Cynomys leucurus Merriam, digging and burrowing into mounds of the western harvester ant, Pogonomyrmex occidentalis (Cresson), in Emery County, Utah.     

Aspen and conifer heterogeneity effects on bird diversity in the northern Yellowstone ecosystem

We addressed the following question: Do conifers within aspen stands (conifer invasion) increase bird species diversity in western landscapes? We tested the hypotheses that bird species diversity, measured as species richness or with the Shannon-Weiner diversity index, responds to aspen-conifer ratios (from 0% to 100% conifer) in a quadratic manner with a maximum occurring at an intermediate ratio of aspen and conifer. Extra sum-of-squares F tests comparing quadratic with linear models suggested that migratory bird diversity was inversely linearly related to the extent of conifer invasion. These linear responses were moderate (species richness: R 2 ≥ 0.34, P 2 ≥ 0.34, P 2 ≤ 0.13, P ≥ 0.09) and was marginal for the Shannon- Weiner diversity index (R 2 ≤ 0.27, P ≤ 0.01). We concluded that mixed aspen-conifer stands do not have higher bird species diversity than pure aspen stands and that management activities should focus on heavily conifer-invaded stands to increase bird diversity in western landscapes and help reverse the decline of aspen habitat due to conifer invasion.     

Aspects of the biology of the flathead chub ( Hybopsis gracilis ) in Montana

Mature flathead chubs ( Hybopsis gracilis ) were present in mid - July and mid - August collections from the Musselshell River, Montana. The estimated numbers of mature eggs present in eight females were 360–753 per female. The smallest mature female and male collected were 113 and 123 mm in total length, respectively. The male to female sex ratio in collections was about 1:1. Only small differences were detected among the length – weight relationships of males and females and samples taken from various seasons and localities in Montana. Observations on size groups, fish associates, and habitat characteristics of flathead chubs are presented.         

Observations on the prey and nests of seven species of Cerceris (Hymenoptera: Sphecidae)

Cerceris species are remarkably constant in their prey preferences. Records are presented from diverse localities that confirm prey constancy in five species. An apparent exception is noted in the case of C. crotonella Viereck & Cockerell. A mixed aggregation of C. fumipennis Say and C. californica Cresson is reported, both preying upon Buprestidae and using some of the same species. Nest and prey of C. conifrons Mickel are reported for the first time.     

生态学研究亟需转化成实际应用

<正>作为一门组织完善的科学学科,生态学已迈入它的第二个世纪:生态学通过大量的实验和丰富的观察,让人类对自然界的运行规律有了基本的理解。今天,环境科学家拥有一系列强有力的工具和技术来测量和监督环境,并解读一大堆各种各样的数据。然而,尽管新信息海量般地涌现,生态学家们却常常无法将他们的知识有效地转化给公众和政策制定者。除非生态科学的发现能     

Selecting wilderness areas to conserve Utah's biological diversity

Congress is currently evaluating the wilderness status of Bureau of Land Management (BLM) public lands in Utah. Wilderness areas play many important roles, and one critical role is the conservation of biological diversity. We propose that objectives for conserving biodiversity on BLM lands in Utah be to (1) ensure the long-term population viability of native animal and plant species, (2) maintain the critical ecological and evolutionary processes upon which these species depend, and (3) preserve the full range of communities, successional stages, and environmental gradients. To achieve these objectives, wilderness areas should be selected so as to protect large, contiguous areas, augment existing protected areas, buffer wilderness areas with multiple-use public lands, interconnect existing protected areas with dispersal and movement corridors, conserve entire watersheds and elevational gradients, protect native communities from invasions of exotic species, protect sites of maximum species diversity, protect sites with rare endemic species, and protect habitats of threatened and endangered species. We use a few comparatively well-studied taxa as examples to highlight the importance of particular BLM lands.     

Observations of captive Rocky Mountain mule deer behavior

Observations were made on the behavior of a captive herd of Rocky Mountain mule deer ( Odocoileus hemionus hemionus ). Comparisons in general behavior patterns were made between captive and wild deer. Similar behavior was exhibited by captive and wild deer. Captive deer (as well as other species) may be useful for study of certain behavioral aspects of their wild counterparts.     

A preliminary classification of the natural vegetation of Colorado

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Notes on the white-tailed antelope squirrel, Ammospermophilus leucurus, and the pinyon mouse, Peromyscus truei, in north central Nevada

A four-season live trapping study in the Whirlwind Valley, on the Lander and Eureka county lines near the Humboldt River, yielded two species previously unrecorded from both counties, Ammospermophilus leucurus and Peromyscus truei. Both records represent minimal airline range extension of 113 and 105 km. It is suggested that the distribution of A. leucurus may include the entire northeastern quadrant of Nevada. The occurrence of P. truei in sagebrush habitat 21 km from the nearest pinyon woodland is unusual and suggests that this species may occur patchily distributed throughout the lower elevation ranges in the northern portion of the state. &nbsp;&nbsp;