Effects of human footprint and biophysical factors on the body-size structure of fished marine species

Marine fisheries in coastal ecosystems in many areas of the world have historically removed large-bodied individuals, potentially impairing ecosystem functioning and the long-term sustainability of fish populations. Reporting on size-based indicators that link to food-web structure can contribute to ecosystem-based management, but the application of these indicators over large (cross-ecosystem) geographical scales has been limited to either fisheries-dependent catch data or diver-based methods restricted to shallow waters (<20 m) that can misrepresent the abundance of large-bodied fished species. We obtained data on the body-size structure of 82 recreationally or commercially targeted marine demersal teleosts from 2904 deployments of baited remote underwater stereo-video (stereo-BRUV). Sampling was at up to 50 m depth and covered approximately 10,000 km of the continental shelf of Australia. Seascape relief, water depth, and human gravity (i.e., a proxy of human impacts) were the strongest predictors of the probability of occurrence of large fishes and the abundance of fishes above the minimum legal size of capture. No-take marine reserves had a positive effect on the abundance of fishes above legal size, although the effect varied across species groups. In contrast, sublegal fishes were best predicted by gradients in sea surface temperature (mean and variance). In areas of low human impact, large fishes were about three times more likely to be encountered and fishes of legal size were approximately five times more abundant. For conspicuous species groups with contrasting habitat, environmental, and biogeographic affinities, abundance of legal-size fishes typically declined as human impact increased. Our large-scale quantitative analyses highlight the combined importance of seascape complexity, regions with low human footprint, and no-take marine reserves in protecting large-bodied fishes across a broad range of species and ecosystem configurations.     

Risk-taking behavior in the lesser wax moth: disentangling within- and between-individual variation

Behaviors that appear to be plastic may well be determined by environmental influences during development. Being able to produce a wide range of variants of one kind of behavior, e.g., a very short and a very long response time to a stimulus under different environmental conditions, can be described as behavioral plasticity. How such behavioral reaction norms develop for individuals is poorly understood, but several factors are likely to play a role. We investigated what factors may affect how the risk-taking behavior of the lesser wax moth, Achroia grisella, is shaped during ontogeny. We manipulated larval density to represent the potential intensity of future competition for females in a lek of males, determined adult moths’ reaction to predator signals, and tested for plasticity in the silence response, i.e., the acoustic evasion behavior of the moths during the experiments. While we found no effect of larval density on either the probability or the duration of the silence response, 11 % of the variance in duration could be explained by differences between families, and 30 % of the variance was the result of differences between individuals. We found evidence for habituation to the predator signal, clearly indicating that the silence response is a plastic-enough trait to be adjustable to the immediate environment. These results suggest that the degree to which individuals take risks in the context of acoustic signaling depends more on the immediate context and, possibly, genetic differentiation than it is a product of adaptive developmental plasticity.     

Accounting for Cadmium: Tracking Emissions of Cadmium From the Global Economy

This paper examines the flow of cadmium through the global economy, with the aim of quantifying emissions of cadmium into the environment as a result of anthropogenic activities. First, a materials balance methodology is presented as the most appropriate means of assessing cadmium emissions from a wide range of anthropogenic sources. This is then applied to the best available data, from a variety of sources, to arrive at estimated flows of cadmium. Results are presented for 10 geo-political world regions and for a range of economic activities including non-ferrous metals production, iron and steel production, combustion of fossil fuels, fertilizer manufacture and use, cement production and the manufacture, use and disposal of cadmium containing products. Initially, this analysis partitions the total flow of cadmium into three major categories: atmospheric emissions, water-borne effluents and solid or bulked waste arisings. the paper then suggests a probable further partition of the initial emissions into different environmental media.     

Do meerkat (<Emphasis Type="Italic">Suricata suricatta</Emphasis>) pups exhibit strategic begging behaviour and so exploit adults that feed at relatively high rates?

Adults vary in their generosity in provisioning the young and their sensitivity to the need of the young. Do the young modulate their behaviour so as to specifically target more high-provisioning adults? This is especially likely in situations with mobile, nutritionally dependent young. We studied cooperatively breeding meerkats Suricata suricatta, in which pups beg to parents and other adults in the group. We found that the young begged differently when next to different adults and that they are consistent in how they beg when next to each adult. Pups next to adults that provision at high rates beg at higher rates and spend longer with them, and these adults are generally more sensitive to increases in begging rate. Such behaviour has adaptive benefits to offspring in terms of increased likelihood of being fed. However, offspring do not appear to be actively seeking out high-provisioning adults or increasing their begging behaviour when they encounter one. Pups did not appear to actively discriminate between adults in their association or begging behaviour. We suggest instead that the relationship between an adult's relative contribution to pup feeding and the behaviour of its accompanying pup is driven by adult behaviour, with responsive adults that feed pups at a relatively higher rate preferentially associating with fast-begging hungry pups.     

Sperm design and variation in the New World blackbirds (Icteridae)

Post-copulatory sexual selection (PCSS) is thought to be one of the evolutionary forces responsible for the rapid and divergent evolution of sperm design. However, whereas in some taxa particular sperm traits are positively associated with PCSS, in other taxa, these relationships are negative, and the causes of these different patterns across taxa are poorly understood. In a comparative study using New World blackbirds (Icteridae), we tested whether sperm design was influenced by the level of PCSS and found significant positive associations with the level of PCSS for all sperm components but head length. Additionally, whereas the absolute length of sperm components increased, their variation declined with the intensity of PCSS, indicating stabilising selection around an optimal sperm design. Given the diversity of, and strong selection on, sperm design, it seems likely that sperm phenotype may influence sperm velocity within species. However, in contrast to other recent studies of passerine birds, but consistent with several other studies, we found no significant link between sperm design and velocity, using four different species that vary both in sperm design and PCSS. Potential reasons for this discrepancy between studies are discussed. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Social experience during adolescence influences how male zebra finches (Taeniopygia guttata) group with conspecifics

Group-living animals rely on social skills which ensure beneficial interaction and prevent harmful ones with conspecifics. In a previous experiment, we demonstrated that male zebra finches reared in groups during adolescence show consistently less courtship and aggressive behaviour as adults than pair-reared males. Here we tested whether such differences affect how they group with conspecifics, as an indicator of their social integration. Zebra finches were kept in pairs (male–female or male–male) or mixed-sex groups (three males and three females) during adolescence and were introduced to an established group of unknown conspecifics during adulthood. Male courtship and aggressive behaviour were quantified directly after introduction to the group and 48 h later. At the same time, male position in relation to other birds and the number of birds in proximity were recorded. Males that grew up in a small mixed-sex group during adolescence spent more time within groups, were observed in bigger groups and lost less weight than males raised in pairs, indicating that an enriched social environment during early development may facilitate social integration. However, we observed no differences in courtship and aggressive behaviour that could predict the differences in grouping behaviour of pair- and group-reared males. We discuss alternative explanations for the difference in grouping and how to test these in future research.     

Predicting arsenic concentrations in groundwater of San Luis Valley,Colorado: implications for individual-level lifetime exposure assessment

Consumption of inorganic arsenic in drinking water at high levels has been associated with chronic diseases. Risk is less clear at lower levels of arsenic, in part due to difficulties in estimating exposure. Herein we characterize spatial and temporal variability of arsenic concentrations and develop models for predicting aquifer arsenic concentrations in the San Luis Valley, Colorado, an area of moderately elevated arsenic in groundwater. This study included historical water samples with total arsenic concentrations from 595 unique well locations. A longitudinal analysis established temporal stability in arsenic levels in individual wells. The mean arsenic levels for a random sample of 535 wells were incorporated into five kriging models to predict groundwater arsenic concentrations at any point in time. A separate validation dataset (n = 60 wells) was used to identify the model with strongest predictability. Findings indicate that arsenic concentrations are temporally stable (r = 0.88; 95 % CI 0.83–0.92 for samples collected from the same well 15–25 years apart) and the spatial model created using ordinary kriging best predicted arsenic concentrations (ρ = 0.72 between predicted and observed validation data). These findings illustrate the value of geostatistical modeling of arsenic and suggest the San Luis Valley is a good region for conducting epidemiologic studies of groundwater metals because of the ability to accurately predict variation in groundwater arsenic concentrations.     

Incorporating basic needs to reconcile poverty and ecosystem services

Conservation managers frequently face the challenge of protecting and sustaining biodiversity without producing detrimental outcomes for (often poor) human populations that depend on ecosystem services for their well-being. However, mutually beneficial solutions are often elusive and can mask trade-offs and negative outcomes for people. To deal with such trade-offs, ecological and social thresholds need to be identified to determine the acceptable solution space for conservation. Although human well-being as a concept has recently gained prominence, conservationists still lack tools to evaluate how their actions affect it in a given context. We applied the theory of human needs to conservation by building on an extensive historical application of need approaches in international development. In an innovative participatory method that included focus groups and household surveys, we evaluated how human needs are met based on locally relevant thresholds. We then established connections between human needs and ecosystem services through key-informant focus groups. We applied our method in coastal East Africa to identify households that would not be able to meet their basic needs and to uncover the role of ecosystem services in meeting these. This enabled us to identify how benefits derived from the environment were contributing to meeting basic needs and to consider potential repercussions that could arise through changes to ecosystem service provision. We suggest our approach can help conservationists and planners balance poverty alleviation and biodiversity protection and ensure conservation measures do not, at the very least, cause serious harm to individuals. We further argue it can be used as a basis for monitoring the impacts of conservation on multidimensional poverty.     

A counterfactual approach to measure the impact of wet grassland conservation on U.K. breeding bird populations

Wet grassland populations of wading birds in the United Kingdom have declined severely since 1990. To help mitigate these declines, the Royal Society for the Protection of Birds has restored and managed lowland wet grassland nature reserves to benefit these and other species. However, the impact of these reserves on bird population trends has not been evaluated experimentally due to a lack of control populations. We compared population trends from 1994 to 2018 among 5 bird species of conservation concern that breed on these nature reserves with counterfactual trends created from matched breeding bird survey observations. We compared reserve trends with 3 different counterfactuals based on different scenarios of how reserve populations could have developed in the absence of conservation. Effects of conservation interventions were positive for all 4 targeted wading bird species: Lapwing (Vanellus vanellus), Redshank (Tringa totanus), Curlew (Numenius arquata), and Snipe (Gallinago gallinago). There was no positive effect of conservation interventions on reserves for the passerine, Yellow Wagtail (Motacilla flava). Our approach using monitoring data to produce valid counterfactual controls is a broadly applicable method allowing large-scale evaluation of conservation impact.