Within-year differences in reproductive investment in laboratory zebra finches (<Emphasis Type="Italic">Taeniopygia guttata</Emphasis>), an opportunistically breeding bird

Reproduction in opportunistically breeding bird species has traditionally been considered non-seasonal with individuals taking advantage of favourable environmental conditions as they arise. However, some studies imply that this opportunistic breeding may be superimposed on an underlying seasonality, which has effects on the readiness to breed when conditions are favourable. The zebra finch (Taeniopygia guttata) is the classic opportunistic breeder and widely used as such in studies. In a series of laboratory-based breeding experiments, we found evidence to suggest that there are seasonal differences in maternal reproductive investment in the zebra finch even when photoperiod, temperature, relative humidity and diet were held constant. Females showed highly significant seasonal differences in clutch size and egg mass with laying order. Clutch size showed a spring/summer peak typical of multi-brooded species in the wild. There was also a significant increase in egg mass with laying order in all seasons except winter. This variation in breeding parameters with season may allow females to adjust investment depending on the potential fitness returns from a given reproductive attempt. These findings also raise a warning about interpreting results of multiple zebra finch breeding experiments that have been carried out in different seasons.     

Chemical contamination of soils in the New York City area following Hurricane Sandy

This paper presents a unique data set of lead, arsenic, polychlorinated biphenyl (PCB), and polycyclic aromatic hydrocarbon (PAH) concentrations in soil samples collected from the metropolitan New York City area in the aftermath of Hurricane Sandy. Initial samples were collected by citizen scientists recruited via social media, a relatively unusual approach for a sample collection project. Participants in the affected areas collected 63 usable samples from basements, gardens, roads, and beaches. Results indicate high levels of arsenic, lead, PCBs, and PAHs in an area approximately 800 feet south of the United States Environmental Protection Agency (US EPA) Superfund site at Newtown Creek. A location adjacent to the Gowanus Canal, another Superfund site, was found to have high PCB concentrations. Areas of high PAH contamination tended to be near high traffic areas or next to sites of known contamination. While contamination as a direct result of Hurricane Sandy cannot be demonstrated conclusively, the presence of high levels of contamination close to known contamination sites, evidence for co-contamination, and decrease in number of samples containing measureable amounts of semi-volatile compounds from samples collected at similar locations 9 months after the storm suggest that contaminated particles may have migrated to residential areas as a result of flooding.     

Postcopulatory sexual selection favours intrinsically good sperm competitors

We used guppies to study repeatability in sperm competitiveness and postcopulatory sexual selection on male ornamentation. In a block design involving 25 pairs of males, artificial insemination was used to mate each pair (A and B) to four unrelated females—two that were mated with the combined ejaculates of both males (sperm-competition treatment) and two receiving sperm from each of the two males individually (single-male treatment). Our analysis revealed significantly repeatable patterns of paternity across females in the sperm-competition treatment, suggesting that certain males are intrinsically better sperm competitors than others, irrespective of female identity. Next, we compared mean brood success (number of offspring per brood) between sperm competition and single-male treatments. We found no significant effect of treatment on female fecundity, suggesting that the previously reported direct benefits of polyandry in this species may be due to factors such as differential maternal effects or differences in the number of inseminated sperm between treatments. Our artificial insemination assay was designed to control both factors. Finally, we determined whether variation in relative paternity was random with respect to male phenotype. Unlike previous work on Trinidadian populations, we found no significant relationship between male sexual ornamentation and sperm competitiveness in the focal population.     

Minimum viable metapopulation size, extinction debt, and the conservation of a declining species.

A key question facing conservation biologists is whether declines in species' distributions are keeping pace with landscape change, or whether current distributions overestimate probabilities of future persistence. We use metapopulations of the marsh fritillary butterfly Euphydryas aurinia in the United Kingdom as a model system to test for extinction debt in a declining species. We derive parameters for a metapopulation model (incidence function model, IFM) using information from a 625-km2 landscape where habitat patch occupancy, colonization, and extinction rates for E. aurinia depend on patch connectivity, area, and quality. We then show that habitat networks in six extant metapopulations in 16-km2 squares were larger, had longer modeled persistence times (using IFM), and higher metapopulation capacity (lambdaM) than six extinct metapopulations. However, there was a > 99% chance that one or more of the six extant metapopulations would go extinct in 100 years in the absence of further habitat loss. For 11 out of 12 networks, minimum areas of habitat needed for 95% persistence of metapopulation simulations after 100 years ranged from 80 to 142 ha (approximately 5-9% of land area), depending on the spatial location of habitat. The area of habitat exceeded the estimated minimum viable metapopulation size (MVM) in only two of the six extant metapopulations, and even then by only 20%. The remaining four extant networks were expected to suffer extinction in 15-126 years. MVM was consistently estimated as approximately 5% of land area based on a sensitivity analysis of IFM parameters and was reduced only marginally (to approximately 4%) by modeling the potential impact of long-distance colonization over wider landscapes. The results suggest a widespread extinction debt among extant metapopulations of a declining species, necessitating conservation management or reserve designation even in apparent strongholds. For threatened species, metapopulation modeling is a potential means to identify landscapes near to extinction thresholds, to which conservation measures can be targeted for the best chance of success.     

Polyphenols and their influence on gut function and health in ruminants: a review

Polyphenols in plants can protect proteins from degradation and improve the efficiency of conversion of plant protein to animal protein (meat and milk), but can this be achieved in a way that is environmentally sustainable, profitable to the livestock farmer and is consistent with aspirations for improved livestock nutrition, health, welfare and product quality? Given that grazed and conserved forage is the bedrock of sustainable ruminant production, this paper attempts to consider what challenges are ahead in terms of enhancing productive efficiency, reducing the polluting footprint of livestock agriculture and alleviating the endemic parasitism that occurs with grazing animals.     

Conservation and Management of a Threatened Madagascar Palm Species, Neodypsis decaryi, Jumelle

The dynamics of a remnant population of the palm Neodypsis decaryi were characterized using a linear, stage-structured demographic model. This palm is a threatened keystone species restricted to a narrow ecological zone in southeastern Madagascar. The population showed high mortality rates in the early stages of the life cycle, followed by a period of lower adult mortality. Demographic results indicated that the population was either stable or increasing inside the reserve (λ _m close to 1.0). Sensitivity and elasticity analyses indicated that adult stage classes were the most sensitive to producing changes in population growth rates. Continued biological monitoring is appropriate for the long-term conservation management of this palm inside the reserve. Outside the protected area the population appears to be declining rapidly, mainly because of anthropogenic effects (especially fire and grazing). If the conservation of Neodypsis decaryi is to be successful in the long term, then conservation methods must be carried out in cooperation with local villagers, and the species should be managed as a renewable resource in situ and ex situ. In situ conservation should include cultivation of this species throughout its natural range and protection of the existing viable natural populations. Alternative conservation management practices, both ecologically and economically sustainable, may be useful to alleviate the human pressures on this renewable resource. If leaves of N. decaryi are to be harvested by local people, we recommend restricting annual harvesting to about 25% of leaves per tree per year. Based on sensitivity analysis, seed collection should be kept well below 95% of the yearly crop if harvesting is not to have a significant impact on population growth rates.     

Assessment of wadeable stream resources in the driftless area ecoregion in Western Wisconsin using a probabilistic sampling design

The Wisconsin Department of Natural Resources (WDNR), with support from the U.S. EPA, conducted an assessment of wadeable streams in the Driftless Area ecoregion in western Wisconsin using a probabilistic sampling design. This ecoregion encompasses 20% of Wisconsin’s land area and contains 8,800 miles of perennial streams. Randomly-selected stream sites (n = 60) equally distributed among stream orders 1–4 were sampled. Watershed land use, riparian and in-stream habitat, water chemistry, macroinvertebrate, and fish assemblage data were collected at each true random site and an associated “modified-random” site on each stream that was accessed via a road crossing nearest to the true random site. Targeted least-disturbed reference sites (n = 22) were also sampled to develop reference conditions for various physical, chemical, and biological measures. Cumulative distribution function plots of various measures collected at the true random sites evaluated with reference condition thresholds, indicate that high proportions of the random sites (and by inference the entire Driftless Area wadeable stream population) show some level of degradation. Study results show no statistically significant differences between the true random and modified-random sample sites for any of the nine physical habitat, 11 water chemistry, seven macroinvertebrate, or eight fish metrics analyzed. In Wisconsin’s Driftless Area, 79% of wadeable stream lengths were accessible via road crossings. While further evaluation of the statistical rigor of using a modified-random sampling design is warranted, sampling randomly-selected stream sites accessed via the nearest road crossing may provide a more economical way to apply probabilistic sampling in stream monitoring programs.     

‘Natural disasters’ and newspapers: Post-tsunami environmental discourse

In this paper we explore the concept of ‘natural disasters’ as opportunities for influencing public perceptions of the environment through the media. We provide a critical analysis of the discourse in a selection of newspaper articles and identify the way in which various actors have utilised UK national newspaper coverage of the Asian tsunami to promote particular agendas and to legitimise policies and actions. A systematic and iterative sampling approach was developed that allowed us to combine quantitative and qualitative methods to search for articles that contained content directly related to the environmental aspects of the tsunami. Three main themes emerged; coastal ecosystems, the fisheries sector, and redevelopment. The discourse within these areas was markedly different. While the coastal ecosystems discourse was hegemonic in terms of narratives and actor coalitions, the fisheries and redevelopment discourse incorporated a more diverse set of actors and storylines that perhaps reflects the lack of consensus on the best way of achieving sustainable solutions. We also contrast the limited discussion and representation of tsunami-related environmental issues within UK national newspapers with the more detailed discussion within the peer-reviewed literature and the grey literature. We argue that ‘natural disasters’ provide both opportunities and risks for raising awareness of environmental issues, mobilising funding and directing action to environmentally and socially vulnerable areas of the world, and that consequently NGOs, intergovernmental bodies and government departments should be mindful of the long-term consequences of global media attention.