Aggregations and offshore movements as indicators of spawning activity of bonefish (Albula vulpes) in The Bahamas

To identify the timing and location of spawning activity for bonefish (Albula spp.) in the Bahamian archipelago, we used an acoustic telemetry array spanning 44?km² of shallow tidal creeks, flats, and adjacent deeper coastal waters near Cape Eleuthera. In two successive years, we surgically implanted transmitters in male and female bonefish (n?=?60) and examined their movement patterns within the array. Eight bonefish surgically implanted with transmitters as part of an earlier study were also tracked. In 2009, the telemetry information was complemented with snorkeling observations, underwater video, and manual tracking of the same acoustically tagged fish, as well as fish (n?=?3) gastrically implanted with continuous transmitters. During a period of 4?C7?days spanning the full and new moons, primarily between October and May, bonefish moved from their typical shallow flats and aggregated at sites in close proximity to the deep water drop-off of the Exuma Sound. Localized movements of the large schools of bonefish (often?>1,000 fish) at these presumptive pre-spawning aggregation sites included brief trips (<8?h) just after sunset until just prior to sunrise to the abyssal wall at the edge of the Exuma Sound (i.e.,?>1,000?m depth). Tagged bonefish detected at these aggregation sites were subsequently detected back in the tidal creeks and coastal flats shortly after new and full moons and remained at these more typical shallow sites (i.e.,?<2?m depth). Although we did not directly observe spawning events, we did observe ventral nudging and porpoising behaviors, which are potentially associated with courtship. Timing of the observed movements and possible courtship behaviors was coincident with periods when gametes were well developed. Collectively, our study provides the first objective evidence suggesting that the aggregation and seasonal migration of bonefish to deep shelf environments during certain moon phases is for spawning.     

Maximizing Benefits from Riparian Revegetation Efforts: Local- and Landscape-Level Determinants of Avian Response

With limited financial resources available for habitat restoration, information that ensures and/or accelerates success is needed to economize effort and maximize benefit. In the Central Valley of California USA, riparian habitat has been lost or degraded, contributing to the decline of riparian-associated birds and other wildlife. Active restoration of riparian plant communities in this region has been demonstrated to increase local population sizes and species diversity of landbirds. To evaluate factors related to variation in the rate at which bird abundance increased after restoration, we examined bird abundance as a function of local (restoration design elements) and landscape (proportion of riparian vegetation in the landscape and riparian patch density) metrics at 17 restoration projects within five project areas along the Sacramento River. We developed a priori model sets for seven species of birds and used an information theoretic approach to identify factors associated with the rate at which bird abundance increased after restoration. For six of seven species investigated, the model with the most support contained a variable for the amount of riparian forest in the surrounding landscape. Three of seven bird species were positively correlated with the number of tree species planted and three of seven were positively correlated with the planting densities of particular tree species. Our results indicate that restoration success can be enhanced by selecting sites near existing riparian habitat and planting multiple tree species. Hence, given limited resources, efforts to restore riparian habitat for birds should focus on landscape-scale site selection in areas with high proportions of existing riparian vegetation.     

Personality and teamwork behavior in context: The cross‐level moderating role of collective efficacy

This research examines whether the relationship between an individual's personality and their behavior within a team is contingent on the team's overall perception of its capability. Individuals were peer‐rated on the extent to which they displayed interpersonal and performance management teamwork behaviors over the course of an 8 week business simulation. The personality trait of agreeableness predicted interpersonal teamwork behavior, while the personality traits of conscientiousness and core self‐evaluation (CSE) predicted performance management behavior. Multilevel analysis showed that collective efficacy influenced the extent to which an individual engaged in both types of behavior, and was also a cross‐level moderator of the relationship between agreeableness and interpersonal behavior and the relationship between CSE and performance management behavior. At the team level, interpersonal behavior mediated between collective efficacy and team performance. The study's results show that in team settings the personality and individual behavior relationship may depend on group level confidence perceptions. Copyright © 2010 John Wiley & Sons, Ltd.     

Spatial and temporal trends of selected trace elements in liver tissue from polar bears (Ursus maritimus) from Alaska, Canada and Greenland

Spatial trends and comparative changes in time of selected trace elements were studied in liver tissue from polar bears from ten different subpopulation locations in Alaska, Canadian Arctic and East Greenland. For nine of the trace elements (As, Cd, Cu, Hg, Mn, Pb, Rb, Se and Zn) spatial trends were investigated in 136 specimens sampled during 2005-2008 from bears from these ten subpopulations. Concentrations of Hg, Se and As were highest in the (northern and southern) Beaufort Sea area and lowest in (western and southern) Hudson Bay area and Chukchi/Bering Sea. In contrast, concentrations of Cd showed an increasing trend from east to west. Minor or no spatial trends were observed for Cu, Mn, Rb and Zn. Spatial trends were in agreement with previous studies, possibly explained by natural phenomena. To assess temporal changes of Cd, Hg, Se and Zn concentrations during the last decades, we compared our results to previously published data. These time comparisons suggested recent Hg increase in East Greenland polar bears. This may be related to Hg emissions and/or climate-induced changes in Hg cycles or changes in the polar bear food web related to global warming. Also, Hg:Se molar ratio has increased in East Greenland polar bears, which suggests there may be an increased risk for Hg(2+)-mediated toxicity. Since the underlying reasons for spatial trends or changes in time of trace elements in the Arctic are still largely unknown, future studies should focus on the role of changing climate and trace metal emissions on geographical and temporal trends of trace elements.     

Sustainability and intergenerational equity: do past injustices matter?

Intergenerational equity is a core concept of sustainability, typically expressed as a concern for future generations. We contend in this review paper that intergenerational equity can also reflect a concern for past generations. Within the study and practice of social justice, significant concern is paid to remedying injustices suffered by past generations, sometimes called “restorative justice,” because these injustices do not end with the past, but remain embedded in the social, economic, and ecological fabrics of our present-day society. We ask: what roles do past injustices play in our understanding of intergenerational justice, and what roles can this understanding play in sustainability thought and practice? We weave together reviews from justice and legal studies and environmental ethics. Several short cases illustrate how restorative justice in practice results in benefits for sustainability, including improved resource management and social cohesion and governance. Our review of sustainability literature shows that while only few of the conceptions of intergenerational equity hint at a concern for historical issues, its concern for intra-generational equity may be a place where restorative issues can be addressed. Within sustainability science approaches, restorative issues may also arise in the assessment of the current state as well as in the appreciation of contextual norms and histories of the places attempting to become more sustainable.     

A comparison of three methods for estimating call densities of migrating bowhead whales using passive acoustic monitoring

Environmental and Ecological Statistics - Various methods for estimating animal density from visual data, including distance sampling (DS) and spatially explicit capture-recapture (SECR), have...     

Multiscale Analysis of Hydrology in a Mountaintop Mine‐Impacted Watershed

In the Appalachian region of the eastern United States, mountaintop removal mining (MTM) is a dominant driver of land‐cover change, impacting 6.8% of the largely forested 4.86 million ha coal fields region. Recent catastrophic flooding and documented biological impairment downstream of MTM has drawn sharp criticism to this practice. Despite its extent, scale, and use since the 1970s, the impact of MTM on hydrology is poorly understood. Therefore, the goal of this study was a multiscale evaluation to establish the nature of hydrologic impacts associated with MTM. To quantify the extent of MTM, land‐cover change over the lifetime of this practice is estimated for a mesoscale watershed in southern West Virginia. To assess hydrologic impacts, we conducted long‐term trend analyses to evaluate for systematic changes in hydrology at the mesoscale, and conducted hydrometric and response time modeling to characterize storm‐scale responses of a MTM‐impacted headwater catchment. Results show a general trend in the conversion of forests to mines, and significant decreases in maximum streamflow and variability, and increases in base‐flow ratio attributed to valley fills and deep mine drainage. Decreases in variability are shown across spatial and temporal scales having important implications for water quantity and quality. However, considerable research is necessary to understand how MTM impacts hydrology. In an effort to inform future research, we identify existing knowledge gaps and limitations of our study.     

Perchlorate in fish from a contaminated site in east-central Texas

Perchlorate, a known thyroid endocrine disruptor, contaminates surface waters near military instillations where solid fuel rocket motors are manufactured or assembled. To assess potential perchlorate exposure to fish and the human population which may feed on them, fish were collected around the Naval Weapons Industrial Reserve Plant in McLennan County, TX, and analyzed for the presence of the perchlorate anion. The sampling sites included Lake Waco and Belton Lake, and several streams and rivers within their watersheds. The general tendency was that perchlorate was only found in a few species sampled, and perchlorate was not detected in every individual within these species. When detected in the fish, perchlorate tissue concentrations were greater than that in the water. This may be due to highly variable perchlorate concentrations in the water coupled with individual-level variation in elimination from the body, or to routes of exposure other than water.