Conserving the abundance of nonthreatened species

Human modification of the environment is driving declines in population size and distributional extent of much of the world's biota. These declines extend to many of the most abundant and widespread species, for which proportionally small declines can result in the loss of vast numbers of individuals, biomass, and interactions. These losses could have major localized effects on ecological and cultural processes and services without elevating a species’ global extinction risk. Although most conservation effort is directed at species threatened with extinction in the very near term, the value of retaining abundance regardless of global extinction risk is justifiable based on many biodiversity or ecosystem service metrics, including cultural services, at scales from local to global. The challenges of identifying conservation priorities for widespread and abundant species include quantifying the effects of species’ abundance on services and understanding how these effects are realized as populations decline. Negative effects of population declines may be disconnected from the threat processes driving declines because of species movements and environment flows (e.g., hydrology). Conservation prioritization for these species shares greater similarity with invasive species risk assessments than extinction risk assessments because of the importance of local context and per capita effects of abundance on other species. Because conservation priorities usually focus on preventing the extinction of threatened species, the rationale and objectives for incorporating declines of nonthreatened species must be clearly articulated, going beyond extinction risk to encompass the range of likely harmful effects (e.g., secondary extinctions, loss of ecosystem services) if declines persist or are not reversed. Research should focus on characterizing the effects of local declines in species that are not threatened globally across a range of ecosystem services and quantifying the spatial distribution of these effects through the distribution of abundance. The case for conserving abundance in nonthreatened species can be made most powerfully when the costs of losing this abundance are better understood.     

Exploring factors that shape small-scale farmers’ opinions on the adoption of eco-friendly nets for vegetable production

If agro-ecological systems are to realize their potential as sustainable alternatives to conventional agricultural systems, innovation diffusion needs to be enhanced. We conducted surveys among 214 small-scale vegetable farmers in Benin, a food-deficit country in West Africa, on how they perceived the different attributes of eco-friendly nets (EFNs). The nets act as physical barriers against insects in vegetable production and so reduce pesticide use. Understanding farmer perceptions about new technologies helps reveal farmers’ propensity to adopt them. Intensity of attitude was measured on a Likert scale, and an ordered probit model was used to determine which characteristics of nets were most influential. Eighteen percent of farmers thought that EFNs would benefit them, but almost half preferred not to adopt this technology at all. The main reason for rejecting the nets was the perceived high labor requirement, particularly on larger plots of land. This largely negative perception was strongest among farmers with large areas cultivated with vegetables, farmers who had little or no experience in a trial, and those living far from extension services. We recommend expanded trials that engage a higher proportion of farmers, strengthening of external support for those wanting to use the nets and further technological development to reduce labor costs, improved access to finance and increased education about the negative impacts of insecticides abuse.     

Evaluating the BANCS Streambank Erosion Framework on the Northern Gulf of Mexico Coastal Plain

The Bank Assessment of Nonpoint source Consequences of Sediment (BANCS) framework allows river scientists to predict annual sediment yield from eroding streambanks within a hydrophysiographic region. BANCS involves field data collection and the calibration of an empirical model incorporating a bank erodibility hazard index (BEHI) and near‐bank shear stress (NBS) estimate. Here we evaluate the applicability of BANCS to the northern Gulf of Mexico coastal plain, a region that has not been previously studied in this context. Erosion rates averaged over two years expressed the highest variability of any existing BANCS study. As a result, four standard BANCS models did not yield statistically significant correlations to measured erosion rates. Modifications to two widely used NBS estimates improved their correlations (r² = 0.31 and r² = 0.33), but further grouping of the data by BEHI weakened these correlations. The high variability in measured erosion rates is partly due to the regional hydrologic and climatic characteristics of the Gulf coastal plains, which include large, infrequent precipitation events. Other sources of variability include variations in bank vegetation and the complex hydro‐ and morphodynamics of meandering, sand bed channels. We discuss directions for future research in developing a streambank erosion model for this and similar regions.     

Evidence for multiple recruitment-cohorts of Puget Sound Dungeness crab,Cancer magister

While sampling intertidally in Puget Sound, Washington, USA, for juvenile Dungeness crab (Cancer magister) in 1984, we found evidence of two distinct cohorts of the same year-class based on sizes of first-instar juveniles (J1) and the spatial/temporal patterns of settlement. In 1988, three distinct cohorts were observed to settle in Puget Sound and its approaches. Settlement of one cohort occurred during May in the Strait of Juan de Fuca and in those areas of Puget Sound closest to the Strait. J1 individuals of this cohort were large (x=7.4 mm carapace width, CW) and comparable in both size and timing of settlement to populations along the Washington coast (e.g. Grays Harbor and Willapa Bay). Initial settlement density of the May cohort was as high as 215 crabs/m² in intertidal eelgrass beds along the Strait of Juan de Fuca and decreased to <2 crabs/m² within Puget Sound and the Strait of Georgia. A second cohort apparently originated in Hood Canal (a deep inland fjord), its size upon settlement in June was significantly smaller (J1 x= 5.3 mm CW) than the May cohort, and it was limited to Hood Canal and areas of Puget Sound close to the mouth of Hood Canal. A third cohort, which settled in late July and August, was the smallest of the three cohorts (J1 x= 4.8 mm CW), and was widely distributed around Puget Sound from Seattle in the south to the USA/Canadian border in the north. We hypothesize that most juvenile recruitment in Hood Canal and Puget Sound originates from parental stocks endemic to their respective basins (Hood Canal and Puget Sound cohorts), but that, on occasion, oceanographic conditions allow substantial influx of Pacific Ocean Dungeness crab larvae (oceanic cohort) through the Strait of Juan de Fuca into Puget Sound. Tracking of spatial/temporal settlement patterns and comparison of J1 sizes proved useful for estimating the probable sources and dispersion of Dungeness crab larvae. Differences in size and time of settlement between various larval cohorts of C. magister may prove useful as biomarkers for tracing circulation patterns within and between inland waters of Washington and the Pacific Ocean. Causes of smaller size and later settlement of the Puget Sound cohort relative to oceanic conspecifics of the same year-class are discussed.Contribution No. 856, School of Fisheries, University of Washington, Seattle     

INEQUITIES FOR SMALL FOOD PROCESSING PLANTS RESULTING FROM LIQUID WASTE TREATMENT REGULATIONS1

ABSTRACT: The cost of the liquid wast treatment measures required to meet federal as well as typical state and local regulations was examined for dairy processing plants of various sizes. Federal effluent standards were found to produce higher estimated capital costs per unit of raw material for smaller plants, even with relaxed requirements for smaller plants. State regulations limiting the effluent BOD₅- concentration were also found to result in inequitable costs for smaller processors. These inequities result from economies of scale and not such factors as level of process technology employed or amount of waste produced per unit of raw material. In contrast, applying an example sewer surcharge formula did not produce inequities from economies of scale.     

Livestock-related greenhouse gas emissions: impacts and options for policy makers

Research shows that livestock account for a significant proportion of greenhouse gas (GHG) emissions and global consumption of livestock products is growing rapidly. This paper reviews the life cycle analysis (LCA) approach to quantifying these emissions and argues that, given the dynamic complexity of our food system, it offers a limited understanding of livestock's GHG impacts. It is argued that LCA's conclusions need rather to be considered within a broader conceptual framework that incorporates three key additional perspectives. The first is an understanding of the indirect second order effects of livestock production on land use change and associated CO₂ emissions. The second compares the opportunity cost of using land and resources to rear animals with their use for other food or non-food purposes. The third perspective is need—the paper considers how far people need livestock products at all. These perspectives are used as lenses through which to explore both the impacts of livestock production and the mitigation approaches that are being proposed. The discussion is then broadened to consider whether it is possible to substantially reduce livestock emissions through technological measures alone, or whether reductions in livestock consumption will additionally be required. The paper argues for policy strategies that explicitly combine GHG mitigation with measures to improve food security and concludes with suggestions for further research.     

The Ethics of Assisted Colonization in the Age of Anthropogenic Climate Change

This paper examines an issue that is becoming increasingly relevant as the pressures of a warming planet, changing climate and changing ecosystems ramp up. The broad context for the paper is the intragenerational, intergenerational, and interspecies equity implications of changing the climate and the value orientations of adapting to such change. In addition, the need to stabilize the planetary climate by urgent mitigation of change factors is a foundational ethical assumption. In order to avoid further animal and plant extinctions, or at the very least, their increased vulnerability to becoming rare and endangered; the systematic assisted colonization of “at risk” species is being seriously considered by scientists and managers of biodiversity. The more practical aspects of assisted colonization have been covered in the conservation biology literature; however, the ethical implications of such actions have not been extensively examined. Our discussion of the value issues, using a novel case study approach, will rectify the limited ethical analysis of the issue of assisted colonization of species in the face of climate change pressures. Beyond sustainability ethics, both animal and environmental ethical approaches will be used and intrinsic versus instrumental value orientations in the literature shall form the basis of our discussion. After the application of all the ethical approaches to the case studies, we conclude that without mitigation and the prospect of a future stable climate, assisted colonization will be involved in an inherently unethical process and a “move and lose it” outcome. With mitigation, there is wide-ranging ethical support for assisted colonization.