bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Pollinator Loss on Endemic New Zealand Mistletoes (Loranthaceae)
Authors: Robertson Alastair W. , Kelly Dave , Ladley Jenny J. , Sparrow Ashley D.
Published: March 2003

Abstract:
The endemic mistletoes Peraxilla colensoi and P. tetrapetala (Loranthaceae) have declined considerably in New Zealand since 1840, reputedly because of introduced herbivores but coincident with a major decline in native bird densities. We show that at two South Island sites ( Craigieburn and Ohau) there are too few bird pollinators visiting the flowers to allow full fruit set. We studied pollination rates in P. colensoi at Wakefield and P. tetrapetala at Craigieburn over four flowering seasons and P. tetrapetala in one season at Ohau. Supplemental hand pollination increased fruit production 1.25–5.3 times at Craigieburn and Ohau but not at Wakefield. Excluding birds by covering mistletoes with mesh bags decreased fruit set significantly at Wakefield but had little effect at Craigieburn and Ohau. Bellbirds (Anthornis melanura) and Tuis (  Prosthemadera novaeseelandiae) visited flowers significantly more often at Wakefield than at Craigieburn. A lack of pollen tubes in the style, not self‐incompatibility or resource shortage, caused the low fruit production in unmanipulated flowers at Craigieburn. Thus, at the two P. tetrapetala sites (Craigieburn and Ohau) fruit set was chronically pollen limited, whereas P. colensoi at Wakefield was not pollen‐limited. Data from other Peraxilla sites also suggest pollination failure. Our study suggests that the conservation of Peraxilla species will require maintenance of native bird populations. Tuis and Bellbirds are important pollinators and dispersers of many other New Zealand plants, and the breakdown of such mutualistic relationships may have widespread consequences.
Landscape Assessment of the Degree of Protection of Alaska's Terrestrial Biodiversity
Authors: Duffy David Cameron , Boggs Keith , Hagenstein Randall H. , Lipkin Robert , Michaelson Julie A.
Published: March 2003

Abstract: We assessed the degree to which Alaskan lands reflect the state's biodiversity by dividing the entire state into four categories of land protection ranging from highly protected to minimally protected in terms of potential for future development. We then compared the percentage of each ecoregion and plant‐cover type in each land protection class. We assumed that 12% protection represents an acceptable minimum and examined the percentage of site records of rare plants in protected and unprotected areas. Of 28 ecoregions in Alaska, 15 (63.4%) have <12% of their area in highly protected areas. Similarly, 11 of 21 vegetation‐cover types (43.7%) have <12% protection. For 32 rare vascular plants, an average of 27% of records occur on highly protected lands. Seventy‐five percent of the rare plants had <50% of their records from highly protected lands. Less than 1% of Alaska has been permanently altered by human activity. In contrast to the lower 48 states, time remains to plan development that preserves biodiversity while permitting an economically sustainable economy—if the effort is made now.
Patterns of Area Sensitivity in Grassland‐Nesting Birds
Authors: Winter Maiken , Faaborg John
Published: March 2003

Abstract: Between 1995 and 1997, we studied breeding birds in fragments of native tallgrass prairie in southwestern Missouri to determine the effect of habitat fragmentation on grassland bird populations. Data on density and nesting success collected in 13 prairie fragments of various sizes revealed three levels of area sensitivity. The most area‐sensitive species, Greater Prairie‐Chicken ( Tympanuchus cupido), was absent from small prairie fragments. An intermediate form of area sensitivity was apparent in only one species, Henslow's Sparrow (Ammodramus henslowii), which occurred in lower densities in small than in large prairie fragments. Based on census (i.e., distributional) data, only those two species were area‐sensitive (i.e., negatively affected by habitat fragmentation) in southwestern Missouri. A species can be sensitive not only on a distributional level, however, but also by having lower nesting success in small than in large prairie fragments. The Dickcissel ( Spiza americana) was the only species that was area‐sensitive on such a demographic level. These data indicate that we cannot rely solely on census data to describe the sensitivity of grassland‐nesting species to habitat fragmentation, but that we also need to investigate demographic data (e.g., nesting success). Whereas it has previously been shown that density measures of forest‐nesting birds do not reliably reflect nesting success in habitat fragments of various sizes, ours is the first study that describes this pattern for grassland‐nesting species.
Effect of Vertebrate Grazing on Plant and Insect Community Structure
Authors: Rambo Jennie L. , Faeth Stanley H.
Published: March 2003

Abstract: We compared species diversity of plants and insects among grazed and ungrazed areas of Ponderosa pine–grassland communities in Arizona. Plant species richness was higher in two of three grassland communities that were grazed by native elk and deer and domestic cattle than in ungrazed areas inside a series of three large (approximately 40‐ha) grazing exclosures. Similarly, plant species richness was higher in grazed areas relative to ungrazed areas at one of two series of smaller (approximately 25‐m2) and short‐term exclosure sites. Evenness of plant distribution, however, was greater inside ungrazed long‐term exclosures but was reduced inside ungrazed short‐term exclosures relative to grazed areas. Relative abundances of forbs, grasses, trees, and shrubs, and native and introduced plants did not differ between the long‐ and short‐term grazing exclosures and their grazed counterparts. Relative abundances of some plant species changed when grazers were excluded, however. In contrast, insect species richness was not different between grazed and ungrazed habitats, although insect abundance increased 4‐ to 10‐fold in ungrazed vegetation. Our results suggest that vertebrate grazing may increase plant richness, even in nutrient‐poor, semi‐arid grasslands, but may decrease insect abundances.
Conservation Genetics at the Species Boundary
Authors: Goldstein Paul Z. , Desalle Robert , Amato George , Vogler Alfried P.
Published: March 2003

Abstract:Conservation genetics has expanded its purview such that molecular techniques are now used routinely to prioritize populations for listing and protection and infer their historical relationships in addition to addressing more traditional questions of heterozygosity and inbreeding depression. Failure to specify whether molecular data are being used for diagnosis‐related questions or for population viability questions, however, can lead either to misinterpretation of character data as adaptive information or to misinterpretation of frequency or distance data as diagnostic or historical information. Each of these misinterpretations will confound conservation programs. The character‐based approach to delimiting phylogenetic species is both operationally and logically superior to “diagnostic” methods that involve distance‐ or frequency‐based routines, which are unstable over time. Tree‐based criteria for the diagnosis of conservation “units” are also inappropriate because they can depend on patterns inferred without reference to diagnostic characters. Intraspecific studies, conservation‐related or otherwise, that adopt terminology and methods designed to infer nested hierarchic relationships confuse diagnosis with historical inferences by treating diagnoses as outcomes rather than as precursors to phylogeny reconstruction. A character‐based diagnostic approach recognizes the analytical dichotomy between species hierarchies and population statistics and provides a framework for the understanding of each. No species concept, however, should be viewed as an absolute criterion for protecting populations, but as part of a framework from within which identification of protection and management goals can be achieved effectively and defensibly.
Characterizing Core and Corridor Use by Nubian Ibex in the Negev Desert, Israel
Authors: Shkedy Yehoshua , Saltz David
Published: March 2003

Abstract: Corridors have become a key element of conservation efforts. To identify and characterize corridors used by Nubian ibex (Capra ibex nubiana), we analyzed sighting data recorded for the past 20 years in the Israel Nature Reserves Authority data banks. We categorized each recorded sighting as belonging to a corridor or a core zone based on the total number of sightings in its vicinity. We identified three main core populations, a natural corridor connecting two of them, and a corridor that was not evident connecting the third population. Ibex inside and outside core zones were sighted on steeper terrain than expected by chance; this was more pronounced inside the core zones than outside them. We hypothesize that because ibex outside core zones must move rapidly and directionally across unfamiliar habitats, they must use more moderate terrain. Although ibex sightings in core zones were mostly in the vicinity of water, we found no relationship between the location of the sightings and proximity to water sources in the corridor. Hence, water does not appear to be an important factor in movement through corridors. It was more common to observe ibex out of the core zones during the summer. Males, which can be twice the size of females, were found traveling alone in corridors more often than in core zones. There was no difference between males and females in the steepness of terrain in which they were sighted outside core zones. Our data show that protecting ibex habitat in core zones and corridors is important to ibex conservation in Israel's arid zones. In addition, protecting this habitat may benefit other rock‐dwelling species in the area.
Poachers Alter Mammal Abundance, Seed Dispersal, and Seed Predation in a Neotropical Forest
Authors: Wright S. Joseph , Zeballos Horacio , Domínguez Iván , Gallardo Marina M. , Moreno Marta C. , Ibáñez Roberto
Published: March 2003

Abstract: We evaluated the hypothesis that poachers reduce the abundance of herbivorous mammals, and that this, in turn, alters seed dispersal, seed predation, and seedling recruitment for two palms (Attalea butyraceae and Astrocaryum standleyanum) in central Panama. Using physical evidence left by poachers and interviews with forest guards, we quantified poaching intensity for eight forest sites. We quantified mammal abundance using transect counts and small‐mammal traps. Abundance was inversely related to poaching intensity for 9 of 11 mammal species (significantly so for 5 species), confirming the first component of the hypothesis. The outcome of interactions among seeds, mammals, and beetles also varied with poaching intensity. Nonvolant mammals were the only seed‐dispersal agents, and rodents and beetles were the only seed predators. We quantified seed fate by examining the stony endocarps that encase the seeds of both palms. The large, durable endocarps were located easily on the forest floor and bear characteristic scars when a rodent or beetle eats the enclosed seed. The proportion of seeds dispersed away from beneath fruiting conspecifics was inversely related to poaching intensity, ranging from 85% to 99% at protected sites where mammals were abundant and from 3% to 40% at unprotected sites where poachers were most active. The proportion of dispersed seeds destroyed by beetles was directly related to poaching intensity, ranging from 0% to 10% at protected sites and from 30% to 50% at unprotected sites. The proportion of dispersed seeds destroyed by rodents was inversely related to poaching intensity, ranging from 85% to 99% at protected sites and from 4% to 50% at unprotected sites. Finally, seedling densities were directly related to poaching intensity. There was no single relationship between poaching intensity and the biotic interactions that determine seedling recruitment. The net effect of poaching on seedling recruitment can be determined only empirically. For these palms, seedling densities were directly related to poaching intensity.
Quantifying Biodiversity: a Phenotypic Perspective
Authors: Owens Ian P.F. , Bennett Peter M.
Published: March 2003

Abstract:With recently derived algorithms, it is possible to calculate the relative phylogenetic distinctiveness of taxa with respect to patterns of phylogenetic branching. We extended this approach by exploring the relative extent to which taxa represent phenotypic biodiversity. We devised a method, based on the use of independent contrasts, that measures the amount of phenotypic change that occurs when lineages diverge. We use this method to quantify the extent to which a taxon represents the phenotypic diversification that has occurred in the past. We applied our method to an analysis of variation in clutch size across 133 avian families. All families did not contribute equally to representing clutch size diversification. The top 10 avian families in terms of representing clutch size diversification were the mesites ( Mesitornithidae), cranes (Gruidae), bustards (Otidae), new world quail (Odontophoridae), seriemas (Cariamidae), finfoots ( Heliornithidae), swallows ( Hirundinidae), megapodes ( Megapodiae), and guans (Cracidae). The 217 species in these 10 families (2.3% of all bird species, 7.5% of families) represented 19.3% of diversification in clutch size. Seventeen percent of overall clutch size diversification was represented by taxa threatened with extinction. The 10 families that represent the greatest proportion of overall clutch size diversification threatened by extinction were the mesites ( Mesitornithidae), kagu ( Rhynochetidae), cranes (Gruidae), kiwis (Apterygidae), new world quail (Odontophoridae), megapodes ( Megapodiae), cassowaries (Casuariidae), finfoots ( Heliornithidae), guans (Cracidae), and logrunners (Orthonychidae). The 42 threatened species (0.5% of all bird species, 3.8% of all threatened bird species) in these 10 families encompassed 53% of the clutch size diversification whose representation was threatened with extinction. Our results suggest that this type of analysis could potentially help prioritize species‐based conservation efforts by identifying those taxa that contribute most toward representing the evolutionary processes that lead to current phenotypic biodiversity.
Effects of Fragmentation of Araucarian Vine Forest on Small Mammal Communities
Authors: Bentley Jocelyn M. , Catterall Carla P. , Smith Geoffrey C.
Published: March 2003

Abstract: Habitat loss and fragmentation are major threats to the survival of forest‐dependent fauna. We examined the abundance of small mammal species in forests, corridors, remnants of araucarian vine forest, and Araucaria cunninghamii plantations and pastures. None of the forest mammal species persisted following conversion of forest to pasture. Plantations supported lowered abundances of a subset of forest species that were mainly habitat generalists with respect to their occurrence in different floristic types of undisturbed native forest. Within plantations, an increased subcanopy cover was associated with a more forest‐like small mammal assemblage. Species' responses to habitat fragmentation varied. The floristic habitat generalists were largely tolerant of habitat fragmentation, their abundance being similar in forests, corridors, and remnants, and were capable of persisting in remnants a few hectares in area. Floristic habitat specialists were vulnerable to habitat fragmentation and thus were abundant in continuous forest, were less abundant in corridors, and were generally absent from remnants. Species that avoid the corridor matrix and are therefore constrained to the corridor may be disadvantaged by the linearity of the habitat, consistent with the predictions of central‐place foraging theory. Although small remnants and corridors provide habitat for some species, those that are more specialized in their use of undisturbed habitat types require the retention or reestablishment of large intact areas.
Incorporating Uncertainty into Management Models for Marine Mammals
Authors: Taylor Barbara L. , Wade Paul R. , De Master Douglas P. , Barlow Jay
Published: March 2003

Abstract: Good management models and good models for understanding biology differ in basic philosophy. Management models must facilitate management decisions despite large amounts of uncertainty about the managed populations. Such models must be based on parameters that can be estimated readily, must explicitly account for uncertainty, and should be simple to understand and implement. In contrast, biological models are designed to elucidate the workings of biology and should not be constrained by management concerns. We illustrate the need to incorporate uncertainty in management models by reviewing the inadequacy of using standard biological models to manage marine mammals in the United States. Past management was based on a simple model that, although it may have represented population dynamics adequately, failed as a management tool because the parameter that triggered management action was extremely difficult to estimate for the majority of populations. Uncertainty in parameter estimation resulted in few conservation actions. We describe a recently adopted management scheme that incorporates uncertainty and its resulting implementation. The approach used in this simple management scheme, which was tested by using simulation models, incorporates uncertainty and mandates monitoring abundance and human‐caused mortality. Although the entire scheme may be suitable for application to some terrestrial and marine problems, two features are broadly applicable: the incorporation of uncertainty through simulations of management and the use of quantitative management criteria to translate verbal objectives into levels of acceptable risk.
Synergisms among Habitat Fragmentation, Livestock Grazing, and Biotic Invasions in Southwestern Australia
Authors: Hobbs Richard J.
Published: March 2003

Abstract: The agricultural development of southern Australia over the past 200 years has resulted in extensively fragmented systems, often with only small, isolated remnants of native vegetation remaining. Grazing by sheep and cattle has affected both the remaining fragments and the surrounding matrix, and non‐native plant and animal species have had dramatic effects on the native biota. Invasive plant species have the potential to significantly alter ecosystem composition and functioning, and invasive animals, particularly rabbits (Oryctolagus cuniculatus), foxes (   Vulpes vulpes) and cats (   Felis catus) effectively alter habitat and drive native fauna to local extinction. These different influences often interact. For instance, smaller fragments are often more prone to plant invasion and are more likely to have been grazed in the past. Invasion of plant species is often linked with livestock grazing or rabbit invasion, and other higher‐order interactions are also apparent. Classical fragmentation studies that concentrate on parameters such as habitat area and isolation but ignore changes in habitat condition brought about by livestock and invasive species are unlikely to yield meaningful results. Similarly, management of fragmented ecosystems must account for not only the spatial characteristics of the remaining habitat but also the importance of other influences, particularly those that impinge on fragments from the surrounding matrix.
Sustainable Human Resources in a Protected Area in Southwestern Gabon
Authors: Thibault Marc , Blaney Sonia
Published: March 2003

Abstract: In central Africa, where governments and funding agencies cover only a fraction of the recurrent expenditures needed to effectively manage the protected‐areas network, it is essential to invest in the people who will be called on to participate in conservation efforts over the long term. In the Gamba Protected Areas Complex in southwestern Gabon, we analyzed the perseverance of all those who participated in training sessions, held since 1996, in ecological survey techniques and in participatory rural appraisal (socioeconomic studies). Of government agents who attended the respective training sessions, 7.7% continued ecological surveys and 0% continued participatory rural appraisal 2 years after training. However, 76.2% and 60.0% of the members of local communities who received training were still active in ecological surveys and participatory rural appraisal respectively after 2 years. Definitive conclusions regarding the participation of nongovernmental organization members cannot be drawn because of the low number of initial participants in the training programs. Based on our results, village collaborators seem to be a more “sustainable” human resource than government agents or of nongovernmental organizations members. Even though local communities cannot be solely responsible for managing protected areas, today's conservation professionals must acknowledge the strengths and limitations of village collaborators. Implementing a process involving the participation and the emulation of community members is a demanding task because protected‐area managers must be based in the field to identify key individuals and to organize intensive training sessions. Also, constant support must be provided during the first years, and then the most capable and motivated collaborators will be able to pursue further training and work their way up through the ranks of the protected area's organizational structure.
Assessment of an Interpretive Program for U.S. Coast Guard Personnel
Authors: Di Mauro Desiree , Dietz Thomas
Published: March 2003

Abstract: The goal of this research was to measure the effect of a print‐based interpretive program on acceptance by U.S. Coast Guard personnel of an endangered‐species protection program. We used a within‐subjects design to measure changes in eight survey items measuring beliefs about endangered species. There were significant changes in three items. The initial attitude toward endangered species was a strong predictor of subsequent response in a “regression to the mean effect” in which the least change was found in subjects with the highest initial scores on attitude items. Our results suggest that the print‐based program was effective at changing the most highly targeted attitudes, but had little effect on more general attitudes.
Implications of Climatic Warming for Conservation of Native Trees and Shrubs in Florida
Authors: Crumpacker David W. , Box Elgene O. , Hardin E. Dennis
Published: March 2003

Abstract: Ecological process models and empirical envelope models have been used to relate climatic‐change predictions to effects on plant species and vegetation. Climatic‐envelope models are useful for simultaneous investigation of many plant species whose range‐limiting mechanisms are poorly known. They are most effectively applied in regions with strong temperature and moisture gradients and low relief. Their required databases are often relatively easy to obtain. We provide an example involving the effect of six annual warming scenarios, ranging from +1° C to +2° C and from +10% to −20% annual precipitation (some have greater warming in winter than in summer), on 117 native woody species in Florida (U.S.A.). Tree species at their southern range boundaries in several parts of Florida are likely to be negatively affected by as little as 1° C warming if it is greater in winter than in summer or is accompanied by a 20% decrease in annual precipitation. Potential species responses to an identical type of 1° C warming may be different for some conservation areas in the same region of Florida. Potentially extensive disruption of some major woody ecosystems is predicted under certain types of 1° C annual warming and under all types of 2° C annual warming that were investigated. Additional consideration of nonclimatic factors suggests that many potential effects on species and ecosystems are not underestimates of actual effects over a 100‐year period of warming. We recommend monitoring for decreased fertility and viability of ecologically important, temperate woody species near their southern range limits in Florida. Early detection of such changes in fitness might then provide time for mitigations designed to alleviate more serious subsequent effects on biodiversity. Control of invasive, non‐native plant species and prevention of their additional introduction, human‐assisted translocation of native subtropical plant species into previously temperate parts of Florida, and restoration of more natural hydrological regimes are examples of potentially useful mitigations if climatic warming continues.
Edge Effects on Lizards and Frogs in Tropical Forest Fragments
Authors: Schlaepfer Martin A. , Gavin Thomas A.
Published: March 2003

Abstract:We investigated whether forest‐pasture edges affect the distribution of an assemblage of small vertebrate ectotherms in a consistent and predictable manner. We describe the abundance and distribution of two species of anoline lizards (  Norops) and five species of leaf‐litter frogs (  Eleutherodactylus) along the edges and in the interiors of nine forest fragments near Las Cruces, Costa Rica. Over 4 months, we surveyed 44 pairs of plots by visual encounter. In each pair of plots, one was immediately adjacent to the pasture and the second was within the forest “interior.” Both plots of a pair were searched simultaneously. This block design controlled for the effects of weather, topography, and searcher ability. The distribution of all species was highly variable with respect to edges. Only two species of frogs,Eleutherodactylus podiciferusandE. cruentus, were significantly more abundant in interior plots than in edge plots, although not consistently so. Both species ofNoropslizards were more abundant along forest edges during the dry season. BothNoropsspecies and severalEleutherodactylusspecies, however, appeared to become more abundant in the forest interior after the onset of the wet season, suggesting a seasonal edge effect. InNorops polylepis, the most abundant anole, rates of ectoparasitism were lower along edges than in forest interiors. The magnitude of the edge effect on any one species was not influenced by the size of fragments or by the distance of the interior plot from the nearest edge. We believe that edge effects should not be defined by the distance to which they are detected. Rather, they should be viewed as highly dynamic in space and time; taxa appear to respond to different components of edge effects according to their particular biological requirements.
Landsat Thematic Mapper: Detection of Shifts in Community Composition of Coral Reefs
Authors: Dustan Phillip , Dobson Eric , Nelson George
Published: March 2003

Abstract: We assembled a time series of 20 Landsat thematic mapper images from 1982 to 1996 for Key Largo, Florida, to ascertain whether satellite imagery can detect temporal changes in coral reef communities. Selected reef and control areas were examined for changes in brightness, spectral reflectance, band ratios, spatial texture, and temporal texture (  pixel‐to‐pixel change over time). We compared the data to known changes in the reef ecosystem of Carysfort Reef and terrestrial sample sites. Changes in image brightness and spectral‐band ratios were suggestive of shifts from coral‐ to algal‐dominated community structure, but the trends were not statistically significant. The spatial heterogeneity of the reef community decreased in the early 1980s at scales consistent with known ecological changes to the coral community on Carysfort Reef. An analysis of pixel‐scale variation through time, termed temporal texture, revealed that the shallow reef areas are the most variable in regions of the reef that have experienced significant ecological decline. Thus, the process of reef degradation, which alters both the spatial patterning and variability of pixel brightness, can be identified in unclassified thematic mapper images.
Using the Phenology of Pond‐Breeding Amphibians to Develop Conservation Strategies
Authors: Paton Peter W. C. , Crouch William B.
Published: March 2003

Abstract: Researchers suggest that regulatory agencies interested in protecting pond‐breeding amphibians should consider wetland isolation, wetland size, and pond hydroperiod (total number of days pond is flooded annually) when modifying existing wetland regulations. Another criterion that has received less attention is the effect of the timing of inundation on the reproductive success of pond‐breeding amphibians. Over 3 years, we monitored the timing of movements of adult and recently metamorphosed anurans and caudates at seven small, isolated wetlands in southern Rhode Island. Based on dates of immigration for adults and emigration for metamorphs, we concluded that different species of amphibians require ponds to be flooded for 125 days to at least 580 days. For species that breed primarily in seasonally flooded ponds, 95% of metamorphs had emigrated from breeding ponds by 31 July in only two species (   Rana sylvatica and Ambystoma opacum), whereas species using semipermanent ponds required inundation until 18 November. Our results suggest that in most years ponds must be inundated for 4–9 months, with water in ponds from March through August, for successful reproduction of the majority of pond‐breeding amphibians in Rhode Island. We recommend that biologists gather data on amphibian movement phenology in other regions to help regulators and managers develop relevant legislation to protect the habitat of pond‐breeding amphibians.
Avian Responses to Late‐Season Grazing in a Shrub‐Willow Floodplain
Authors: Stanley Thomas R. , Knopf Fritz L.
Published: March 2003

Abstract: Riparian vegetation in western North America provides important habitat for breeding birds and valuable forage for grazing livestock. Whereas a number of studies have documented the response of riparian vegetation to the removal of cattle, few have experimentally evaluated specific grazing systems. We evaluated the responses of vegetation and breeding birds to two cycles of late‐season (August–September) grazing followed by 34 months of rest on the Arapaho National Wildlife Refuge, Colorado. We used a before‐and‐after control‐impact (BACI) design, with two control (ungrazed) and two treatment ( grazed) pastures composing the experimental units. Vegetation characteristics and bird densities were quantified on sample plots prior to and following two cycles of the treatment. We found no statistical differences in vegetation change and few differences in bird‐density change among pastures. Inspection of means for pastures, however, suggests that changes in shrub vigor and spatial pattern differed among ungrazed and grazed pastures and that changes in population density for three of the nine bird species and three guilds studied differed among pastures. Our results suggest that habitat for grazing‐sensitive birds may be restored while still allowing late‐season grazing, although the rate at which species are recovered will be slower than if all cattle are removed.
Evaluation of the Chesapeake Bay Foundation's Conservation Education Programs
Authors: Zint Michaela , Kraemer Anita , Northway Heather , Lim Miyoun
Published: March 2003

Abstract: We conducted an evaluation of the Chesapeake Bay Foundation's conservation education programs to determine to what extent they promote participants' environmentally responsible behavior and reduce teachers' perceived barriers to teaching about the bay. We assessed outcomes of five youth‐ and two teacher‐education programs through pre‐, post‐, and retention‐tests and mail questionnaires from samples of current and past participants. Based on improvements in characteristics that promote environmentally responsible behavior, such as perceived knowledge of issues and actions, environmental sensitivity, and—particularly—intention to act, we concluded that the education programs increased some youths' and many teachers' environmentally responsible behavior. We also concluded that the teacher‐education programs facilitated teaching about the bay by reducing teachers' constraints. As a result of our evaluation, the Chesapeake Bay Foundation implemented several changes that administrators of similar conservation education programs may also want to consider. These changes include focusing programs to target specific, suitable goals; coordinating programs to provide experiences that build on one another; and conducting periodic evaluations.
Sagebrush‐Steppe Vegetation Dynamics and Restoration Potential in the Interior Columbia Basin, U.S.A.
Authors: Hemstrom Miles A. , Wisdom Michael J. , Hann Wendel J. , Rowland Mary M. , Wales Barbara C. , Gravenmier Rebecca A.
Published: March 2003

Abstract: We modeled the dynamics and restoration of sagebrush ( Artemisia spp.) habitats for Greater Sage‐Grouse ( Centrocercus urophasianus) in the interior Columbia Basin and adjacent portions of the Great Basin ( referred to as the basin). Greater Sage‐Grouse have undergone widespread decline and are the focus of conservation on over 13 million ha of sagebrush steppe in the basin, much of which is managed by the U.S. Forest Service ( FS) and U.S. Bureau of Land Management ( BLM ). Consequently, we evaluated changes in the amount and quality of sage‐grouse habitat on 8.1 million ha of FS–BLM lands in the basin. Changes were estimated from historical to current conditions and from current conditions to those projected 100 years in the future under proposed management and under two restoration scenarios. These two scenarios were designed to improve long‐term (100 ‐year) projections of sage‐grouse habitat on FS–BLM lands in relation to current conditions and proposed management. Scenario 1 assumed a 50% reduction in detrimental grazing effects by livestock ( through changes in stocking rates and grazing systems) and a six‐fold increase in areas treated with active restoration relative to proposed management. Scenario 2 assumed a 100% reduction in detrimental grazing effects and the same level of active restoration as scenario 1. Under the two scenarios, the amount of FS–BLM habitat for sage grouse within treated areas declined by 17–19% 100 years in the future compared with the current period, but was 10–14% higher than the 100‐year projection under proposed management. Habitat quality under both scenarios was substantially improved compared with the current period and proposed management. Our results suggest that aggressive restoration could slow the rate of sagebrush loss and improve the quality of remaining habitat.
Alternative Configurations of Conservation Reserves for Paraguayan Bats: Considerations of Spatial Scale
Authors: Andelman Sandy J. , Willig Michael R.
Published: March 2003

Abstract: The application of systematic and quantitative approaches to conservation planning is increasing, but the quality and quantity of data available to planners remains inadequate. We used two databases on bat species distributions at 25 sites in Paraguay to illustrate some of the effects of the spatial scale of sampling and data quality on decisions about reserve siting. We used a simulated annealing algorithm to identify alternative scenarios for comprehensive representation of the nation's bat fauna within a system of reserves and to evaluate the contribution of existing protected areas in Paraguay to this conservation goal. The location, efficiency, and level of protection (i.e., the number of populations of each species protected) were affected by both spatial scale and source of data. Our results suggest that systematic and intensive biodiversity surveys are an important element of efficient conservation planning for biodiversity conservation.
Patterns of Rodent Abundance on Open‐Space Grasslands in Relation to Suburban Edges
Authors: Bock Carl E. , Vierling Kerri T. , Haire Sandra L. , Boone John D. , Merkle William W.
Published: March 2003

Abstract: Relatively little is known about the response of grassland rodent populations to urban and suburban edges. We live‐trapped rodents for three summers on 65 3.1‐ha grassland plots on open space of the city of Boulder, Colorado, and compared capture rates among species according to habitat type, percentage of the 40 ha surrounding each plot that was suburbanized, and proximity to a suburban edge. Deer mice (   Peromyscus maniculatus) and hispid pocket mice ( Chaetodipus hispidus) were more abundant on interior than on edge plots in mixed grasslands, whereas prairie voles (   Microtus ochrogaster) were captured more often on interior than on edge plots in tallgrass/hayfields. House mouse (   Mus musculus) abundance did not differ between edge and interior plots. Native rodents as a group were captured more often on interior than on edge plots in both habitat types. For each native species, plots with the highest capture rates were in landscapes <10% suburbanized. We conclude that proximity to suburban landscapes had a strongly negative effect on the abundance of native rodents in open‐space grasslands.
The Colony Structure and Population Biology of Invasive Ants
Authors: Tsutsui Neil D. , Suarez Andrew V.
Published: March 2003

Abstract:Ants are among the most widespread and damaging of introduced species. Many invasive ants share a suite of characteristics that facilitate their introduction, establishment, and subsequent range expansion. One feature of particular importance is the ability to form numerically large, ecologically dominant colonies. We review the population biology of invasive ants, focusing on the role of sociality and colony structure in their success. Specifically, we considered different hypotheses that have been proposed for the observed transitions in social structure of the two most well‐studied ant invaders, the Argentine ant (   Linepithema humile) and the red imported fire ant (   Solenopsis invicta). In both species, genetic changes during or subsequent to introduction have led to alterations in social behavior and colony structure; these, in turn, have promoted the invasive success of introduced populations. Although many other invasive ant species appear to have similar forms of social organization, little is known about the basic population biology of these species.
Soft Versus Rigid Vacuum Extractor Cups for Assisted Vaginal Delivery
Authors: Johanson R.B. , Menon B.K.V.
Published: March 2003

A substantive amendment to this systematic review was last made on 22 June 1999. Cochrane reviews are regularly checked and updated if necessary.

Background and objectives: The original cups used for vacuum extraction delivery of the fetus were rigid metal cups. Subsequently, soft cups of flexible materials such as silicone rubber or plastic were introduced. Soft cups are thought to have a poorer success rate than metal cups. However, they may be less likely to be associated with scalp trauma, easier to apply and less likely to injure the mother. The objective of this review was to assess the effects of soft versus rigid vacuum extractor cups on perineal injury, fetal scalp injury, short and long term pain and success rate.

Search strategy: We searched the Cochrane Pregnancy and Childbirth Group trials register.

Selection criteria: Acceptably controlled comparisons of soft versus rigid vacuum extractor cups.

Data collection and analysis: Two reviewers assessed trial quality and extracted data. Study authors were contacted for additional information.

Main results: Nine trials involving 1375 women were included. The trials were of average quality. Soft cups are significantly more likely to fail to achieve vaginal delivery (odds ratio 1.65, 95% confidence interval 1.19–2.29). However, they were associated with less scalp injury (odds ratio 0.45, 95% confidence interval 0.15–0.60). There was no difference between the two groups in terms of maternal injury.

Reviewers' conclusions: Metal cups appear to be more suitable for “occipito‐posterior,” transverse and difficult “occipito‐anterior” position deliveries. The soft cups seem to be appropriate for straightforward deliveries.

Citation: Johanson RB, Menon BKV. Soft versus rigid vacuum extractor cups for assisted vaginal delivery (Cochrane Review). In: The Cochrane Library, Issue 4, 1999. Oxford: Update Software.

•••

The preceding reports are abstracts of regularly updated, systematic reviews prepared and maintained by the Cochrane Collaboration. The full texts of the reviews are available in The Cochrane Library (ISSN 1464–780X).

See http://www.update‐software.com/cochrane.htm, or contact Update Software,info@update.co.uk, for information on subscribing to The Cochrane Library in your area.

Update Software Ltd., Summertown Pavilion, Middle Way, Oxford OX2 7LG, United Kingdom (Tel.: + 44 1865 513902; Fax: + 44 1865 516918).
Soft Versus Rigid Vacuum Extractor Cups for Assisted Vaginal Delivery
Authors: Johanson R.B. , Menon B.K.V.
Published: March 2003

A substantive amendment to this systematic review was last made on 31 December 1998.

Background and objectives: Proponents of vacuum delivery argue that it should be chosen first for assisted vaginal delivery, because it is less likely to injure the mother. The objective of this review was to assess the effects of vacuum extraction compared to forceps, on failure to achieve delivery and maternal and neonatal morbidity.

Search strategy: We searched the Cochrane Pregnancy and Childbirth Group trials register.

Selection criteria: Acceptably controlled comparisons of vacuum extraction and forceps delivery.

Data collection and analysis: Two reviewers independently assessed trial quality and extracted data. Study authors were contacted for additional information.

Main results: Ten trials were included. The trials were of reasonable quality. Use of the vacuum extractor for assisted vaginal delivery when compared to forceps delivery was associated with significantly less maternal trauma (odds ratio 0.41, 95% confidence interval 0.33–0.50) and with less general and regional anaesthesia. There were more deliveries with vacuum extraction (odds ratio 1.69, 95% confidence interval 1.31–2.19). Fewer caesarean sections were carried out in the vacuum extractor group. However, the vacuum extractor was associated with an increase in neonatal cephalhaematomata and retinal haemorrhages. Serious neonatal injury was uncommon with either instrument.

Reviewers' conclusions: Use of the vacuum extractor rather than forceps for assisted delivery appears to reduce maternal morbidity. The reduction in cephalhaematoma and retinal haemorrhages seen with forceps may be a compensatory benefit.

Citation: Johanson RB, Menon BKV. Vacuum extraction versus forceps for assisted vaginal delivery (Cochrane Review). In: The Cochrane Library, Issue 2, 1999. Oxford: Update Software.
Umbilical Cord Blood Collection, Banking, and Transplantation: Current Status and Issues Relevant to Perinatal Caregivers
Authors: Smith Franklin O , Thomson Blythe G
Published: March 2003

As a result of recent media coverage of cord blood transplantation, expectant parents increasingly ask perinatal caregivers about the possibility of collecting and saving their newborn child's umbilical cord blood. Umbilical cord blood has been used as a source of hematopoeitic stem cells for the treatment of human disease since 1988. As a result of these initial successes, cord blood collection, banking, and transplantation has become increasingly used worldwide, giving rise to several controversies. We have reviewed the current status of the indications for cord blood collection, the methods of collection, and safety issues related to the cyropreservation of cord blood units. In addition, the clinical success of cord blood transplants from related and unrelated donors is detailed. We have examined the major issues concerning cord blood transplantation as it exists in the year 2000 to provide insight into this exciting area of clinical investigation.
The Dilemma of Postnatal Mother‐to‐Child Transmission of HIV: To Breastfeed or Not?
Authors: Weinberg Geoffrey A
Published: March 2003

The promotion of nearly universal breastfeeding has played an important role in improving child health by providing optimum nutrition and protection against common childhood infections, and by promoting child spacing. Unfortunately, it has become clear that breastfeeding is responsible also for much of the increasing burden of worldwide pediatric human immunodeficiency virus (HIV) infection, especially in the developing nations (12–14% additional risk of HIV infection transmitted by breastfeeding; 35% total proportion of all HIV‐infected children in an area infected through breastfeeding). Several factors influence the transmission of HIV by breastfeeding, including whether a woman acquires her infection during breastfeeding (29% risk of transmission) or before pregnancy (7–10% risk of breastfeeding transmission),the degree of maternal plasma and breastmilk viral load, and the presence of mastitis. In areas of the world where adequate sanitary replacement feeding is not available, the decision to withhold breastfeeding so as to decrease HIV transmission may lead to increased rates of child morbidity and mortality from diarrheal and respiratory diseases, and malnutrition. This review summarizes current data on the pathophysiology of breastfeeding transmission of HIV infection, the risk factors for and incidence rates of transmission, and the feasibility of possible alternatives to exclusive breastfeeding in the setting of maternal HIV infection. Clearly, women must be fully informed about the risks of breastfeeding transmission of HIV, the risks of morbidity and mortality among nonbreastfed infants, and the expense and availability of procuring adequate replacement formula. If an uninterrupted access to a nutritionally adequate breastmilk substitute that can be safely prepared is ensured (as is possible in industrialized countries), HIV‐infected women should be counseled not to breastfeed their infants.
Helicobacter pylori Colonization Density and Gastric Acid Output in Non‐ulcer Dyspepsia and Duodenal Ulcer Disease
Authors: Mullins Paul D. , Steer Howard W.
Published: March 2003

Background.

The pattern of intragastric Helicobacter pylori colonization and its density may be determined by parietal cell function. H. pylori bacterial products can inhibit gastric acid secretion from the parietal cell. The aim of this investigation was to study the relationship between acid output and intragastric H. pylori distribution and colonization density in duodenal ulcer (DU) and non‐ulcer subjects. The study included 14 patients with active DU, 10 with inactive DU and 10 non‐ulcer dyspeptics.

Methods.

Acid output studies in response to fasting and maximal pentagastrin stimulation, basal (BAO) and peak (PAO) acid outputs were calculated. A quantitative assessment of H. pylori colonization density in biopsies from five sites of the gastroduodenum in the active ulcer group, and from the antrum in inactive duodenal ulcer and non‐ulcer groups.

Results.

There were negative correlations between total gastroduodenal bacterial colonization density and, PAO (r− 0.87, p = 0.0025) and BAO (r− 0.635, p < 0.02) in the active ulcer group. There were negative correlations between antral H. pylori colonization density and PAO in the active duodenal ulcer (r− 0.7449, p < 0.01) and non‐ulcer (r− 0.5837, p < 0.1) groups but not in the inactive duodenal ulcer group (r− 0.1869, p > 0.2).

Conclusions.

An equilibrium is reached between gastroduodenal H. pylori colonization density and gastric acid secretory capacity in active duodenal ulcer disease. It is hypothesized that thresholds of bacterial load and acid secretory capacity, in combination, are required for active ulceration in DU disease.