Linking direct and indirect data on dispersal: isolation by slope in a headwater stream salamander

There is growing recognition of the need to incorporate information on movement behavior in landscape-scale studies of dispersal. One way to do this is by using indirect indices of dispersal (e.g., genetic differentiation) to test predictions derived from direct data on movement behavior. Mark-recapture studies documented upstream-biased movement in the salamander Gyrinophilus porphyriticus (Plethodontidae). Based on this information, we hypothesized that gene flow in G. porphyriticus is affected by the slope of the stream. Specifically, because the energy required for upstream dispersal is positively related to slope, we predicted gene flow to be negatively related to change in elevation between sampling sites. Using amplified DNA fragment length polymorphisms among tissue samples from paired sites in nine streams in the Hubbard Brook Watershed, New Hampshire, USA, we found that genetic distances between downstream and upstream sites were positively related to change in elevation over standardized 1-km distances. This pattern of isolation by slope elucidates controls on population connectivity in stream networks and underscores the potential for specific behaviors to affect the genetic structure of species at the landscape scale. More broadly, our results show the value of combining direct data on movement behavior and indirect indices to assess patterns and consequences of dispersal in spatially complex ecosystems.     

Mating tactics and mating system of an aquatic-mating pinniped: the harbor seal, <Emphasis Type="Italic">Phoca vitulina</Emphasis>

Our best understanding of marine mammal mating systems comes from land-mating pinnipeds. Logistical problems of observing behavior at sea have limited our ability to make inferences about species with aquatic-mating systems, which comprise over half the pinnipeds. The mating systems of these species likely involve different mating tactics than land-mating species. We used several methods in combination (e.g., animal-borne cameras, radio telemetry, time-depth recorders, and DNA paternity assessment) to provide a comprehensive study of the aquatic-mating tactics of harbor seal males. Males decreased time offshore (26.0 vs 14.8%) and increased time near shore (33.8 vs 43.7%) between premating and mating periods, respectively. Concomitantly, males reduced foraging effort and increased activities associated with competition for females (e.g., visual/vocal displays and threats). As females come into estrus near the end of lactation and spend more time at sea, males reduced their near-shore ranges (4.2 vs 1.0 km²), which were clustered within 1–1.5 km of the beach where females attended their pups. Body mass of males was not a major factor affecting their reproductive behavior. From a small number of paternity assignments to study males, it appears that females select males. These combined results are more consistent with a lek-type mating system than with the territorial or female defense systems characteristic of land-mating pinnipeds.     

Quality assurance/quality control programs in some U.S. environmental laboratories

The quality control program of the Environmental Measurements Laboratory in radioactivity measurements is described and some results are reported.     

Ripples in a pond: an open system model of the evolution of safety culture.

The development of an effective safety culture is essential to promote safe operations. Previous studies have either identified the characteristics of effective safety culture analytically, inferring them from signs and symbols derived from working practices, or have restricted the study of the development of safety culture to workers within an organisation. This paper describes a large-scale survey-based study in which the factors influencing the evolution of safety culture are identified empirically and, drawing upon open systems theory, are also extended beyond the bounds of the organisation. Three major determinants of safety culture are identified: safety concerns, influences and actions. Sub-components within each of these categories are also identified and the relationship between them is hypothesised.     

Monitoring of radiation and radioactivity in the environment

This report lists the programs for monitoring radiation and radioactivity in the environment that are known to be in operation or to have been in operation recently. It is intended as a guide to be used when seeking information on the programs of other institutions. Sources of the data have been the literature and personal correspondence and discussions.The programs are divided into the categories of weapons test fallout, natural activity and environmental monitoring of releases from specific facilities. Where possible, the types of measurements being made are also listed. While the data are as up to date as possible the field is changing rapidly and there may be ommissions.     

Application of a cave inventory system to stimulate development of management strategies: the case of west-central Florida, USA

The active management of air-filled cave systems is virtually non-existent within the karst landscape of west-central Florida. As in every karst landscape, caves are important because they contain a wide variety of resources (e.g., biota, speleothems) and can act as direct connections between surface and subsurface hydrological processes, potentially exacerbating the pollution of groundwater. Before sound management policies can be drafted, implemented, and enforced, stakeholders must first have knowledge of the management requirements of each cave. However, there is an informational disconnect between researchers, stakeholders, and the recreational caving community. Here, we present a cave inventory system that simplifies the dissemination of resource knowledge to stakeholders so that cave management and protection policies can be drafted and implemented at the state and local level. We inventoried 36 caves in west-central Florida, located on both public and private land, and analyzed cave resource data to provide insights on cave sensitivity and disturbance using two standardized indices. The data revealed that both public and private caves exhibit a wide range of sensitivity and disturbance, and before management strategies can be drafted, the ownership of each cave must be considered. Our inventory geodatabase serves as a link between researchers, landowners, and the public. To ensure the conservation and protection of caves, support from county or state government, combined with cave inventory data, is crucial in developing sound management policy.     

Integrative trophic network assessments of a lentic ecosystem by key ecological approaches of water chemistry, trophic guilds, and ecosystem health assessments along with an ECOPATH model

The objective of this study was to describe the trophic structure and energy flow in a lentic ecosystem in South Korea. Physicochemical water conditions were evaluated along with the reservoir ecosystem health using a multimetric IBI model. Nutrient analyses of the reservoir showed a nutrient rich and hypereutrophic system. Guild analysis revealed that tolerant and omnivorous species dominated the ecosystem. Tolerant fish, as a proportion of the number of individuals, were associated (R² > 0.90, p < 0.01) with TN and TP, the key indicators of trophic state in lentic ecosystems. The mean Reservoir Ecosystem Health Assessment (REHA) score was 19.3 during the study, which was judged as in ‘fair to poor’ condition. A trophic analysis of the reservoir estimated by the ECOPATH model shows that most activity in terms of energy flow occurred in the lower part of the trophic web, where there was intensive use of primary producers as a food source. Consequently, of the 10 consumer groups, nine fell within trophic levels <2.8. Trophic levels (TL) estimated from the weighted average of prey trophic levels varied from 1.0 for phytoplankton, macrophytes, and detritus to 3.25 for the top predator, Pseudobagrus fulvidraco. Our integrated approach to trophic network analysis may provide a key tool for determining the effects of nutrient influx on energy flow pathways in lentic ecosystems.     

How important is wilderness? Results from a United States Survey

The designation and management of federal wilderness areas has generated much controversy in the United States. The decade of the 1980s has been a difficult one for public land managers as there has been growing opposition to their traditional “conserve but use philosophy.” Public lands are to be managed for the public benefit. Unfortunately there has been little survey research to find out what the attitudes of the public are towards the management of federally designated wilderness. We report the results of a national survey of 2670 residents of wilderness counties. We found that the presence of wilderness is an important reason why 53% of the people moved to or live in the area; 81% felt that wilderness areas are important to their counties; and 65% were against mineral or energy development in wilderness areas. On some issues there was less agreement as 43% of the respondents wanted more access to wilderness, and 39% were in favor of additional wilderness with 26% undecided. There were no large differences between counties and regions despite the differences in economic and social characteristics and the historical contexts within which they evolved.     

Cytotoxicity induced by the mixture components of nickel and poly aromatic hydrocarbons

Environmental Geochemistry and Health - Although particulate matter (PM) is composed of various chemicals, investigations regarding the toxicity that results from mixing the substances in PM are...     

Resolving future fire management conflicts using multicriteria decision making

Management strategies to reduce the risks to human life and property from wildfire commonly involve burning native vegetation. However, planned burning can conflict with other societal objectives such as human health and biodiversity conservation. These conflicts are likely to intensify as fire regimes change under future climates and as growing human populations encroach farther into fire‐prone ecosystems. Decisions about managing fire risks are therefore complex and warrant more sophisticated approaches than are typically used. We applied a multicriteria decision making approach (MCDA) with the potential to improve fire management outcomes to the case of a highly populated, biodiverse, and flammable wildland–urban interface. We considered the effects of 22 planned burning options on 8 objectives: house protection, maximizing water quality, minimizing carbon emissions and impacts on human health, and minimizing declines of 5 distinct species types. The MCDA identified a small number of management options (burning forest adjacent to houses) that performed well for most objectives, but not for one species type (arboreal mammal) or for water quality. Although MCDA made the conflict between objectives explicit, resolution of the problem depended on the weighting assigned to each objective. Additive weighting of criteria traded off the arboreal mammal and water quality objectives for other objectives. Multiplicative weighting identified scenarios that avoided poor outcomes for any objective, which is important for avoiding potentially irreversible biodiversity losses. To distinguish reliably among management options, future work should focus on reducing uncertainty in outcomes across a range of objectives. Considering management actions that have more predictable outcomes than landscape fuel management will be important. We found that, where data were adequate, an MCDA can support decision making in the complex and often conflicted area of fire management.