Temperature-associated population diversity in salmon confers benefits to mobile consumers

Habitat heterogeneity can generate intraspecific diversity through local adaptation of populations. While it is becoming increasingly clear that population diversity can increase stability in species abundance, less is known about how population diversity can benefit consumers that can integrate across population diversity in their prey. Here we demonstrate cascading effects of thermal heterogeneity on trout-salmon interactions in streams where rainbow trout rely heavily on the seasonal availability of anadromous salmon eggs. Water temperature in an Alaskan stream varied spatially from 5 degrees C to 17.5 degrees C, and spawning sockeye salmon showed population differentiation associated with this thermal heterogeneity. Individuals that spawned early in cool regions of the 5 km long stream were genetically differentiated from those spawning in warmer regions later in the season. Sockeye salmon spawning generates a pulsed resource subsidy that supports the majority of seasonal growth in stream-dwelling rainbow trout. The spatial and temporal structuring of sockeye salmon spawn timing in our focal stream extended the duration of the pulsed subsidy compared to a thermally homogeneous stream with a single population of salmon. Further, rainbow trout adopted movement strategies that exploited the multiple pulses of egg subsidies in the thermally heterogeneous stream. Fish that moved to track the resource pulse grew at rates about 2.5 times higher than those that remained stationary or trout in the reference stream with a single seasonal pulse of eggs. Our results demonstrate that habitat heterogeneity can have important effects on the population diversity of dominant species, and in turn, influence their value to species that prey upon them. Therefore, habitat homogenization may have farther-reaching ecological effects than previously considered.     

Water and economic development: The role of variability and a framework for resilience

The article advances the hypothesis that the seasonal and inter‐annual variability of rainfall is a significant and measurable factor in the economic development of nations. An analysis of global datasets reveals a statistically significant relationship between greater rainfall variability and lower per capita GDP. Having established this correlation, we construct a water resources development index that highlights areas that have the greatest need for storage infrastructure to mitigate the impacts of rainfall variability on water availability for food and basic livelihood. The countries with the most critical infrastructure needs according to this metric are among the poorest in the world, and the majority of them are located in Africa. The importance of securing water availability in these nations increases every day in light of current population growth, economic development, and climate change projections.     

The Chemical Composition and Flow of the River Lea, Spain

Weekly measurements of chemical composition were made at four sampling sites on the Lea River (Spain) between July 1985 and August 1986. at two stations there were gauging-weirs for stream discharge monitoring. Conductivity, pH, alkalinity, silicon, calcium, magnesium, sodium, potassium, ammonia, nitrate, sulphate, chloride, reactive phosphate, and total phosphate, were recorded in each site.

Results were analysed using multiple regression techniques to study the relationship between flow and chemical components.

Conductivity, alkalinity, calcium, magnesium and sulphate were strongly related to flow, decreasing in concentration with increased flow. Ammonia, potassium, reactive phosphate and total phosphate varied most widely, with peaks at times of heavy rainfall. Nitrate increased at times of high discharge, with little variation between sampling points. Silicon decreased in summer and autumn in the lower catchment area whilst chloride and sodium were higher in the lower catchment of the River Lea.     

Östrogenartige wirkungen von bisphenol a auf vorderkiemenschnecken (Mollusca: Gastropoda: Prosobranchia)

Within a Federal Environmental Agency research project to develop a biological test for hormone-mimetic compounds using the freshwater snail Marisa cornuarietis, the effects of the suspected xenoestrogenic substance bisphenol A (BPA), not only on freshwater but also on marine prosobranch snails, were investigated. For the laboratory experiments the ramshorn snail Marisa cornuarietis and the ovoviviparous snail Potamopyrgus antipodarum were considered as freshwater species and two marine prosobranchs, the netted whelk Nassarius reticulatus and the dog whelk Nucella lapillus, were additionally employed. N. reticulatus, as a typical sediment-living species, was exposed via artificial sediments, while the three other prosobranchs were exposed via water. The test series with Marisa cornuarietis covered a nominal concentration range between 1 and 100 μg BPA/l in a 5 month experiment with adult snails and a complete life cycle test for 12 months. Additionally, a third test in the nominal range between 0.05 and 1 μg BPA/l (measured: 0.0079–0.404 μg/l) was performed with adults snails for 6 months. In these experiments, BPA induced a complex syndrome of physiological and morphological alterations in female Marisa referred to as the induction of ‘superfemales’. Affected specimens were characterised by the formation of additional female organs, an enlargement of the accessory pallial sex glands, gross malformations of the pallial oviduct section resulting in an increased female mortality, and a massive stimulation of oocyte and spawning mass production. For these tests, an LOEC of 48.3 ng/l, an NOEC of 7.9 ng/l and an EC₁₀ of 13.9 ng/l were calculated. Superfemales occurred also in the BPA exposure experiment with the other snail species, but comparable oviduct malformations as in Marisa were not found, probably due to species differences in the gross anatomical structure of the pallial oviduct. During the 9 week test with Potamopyrgus antipodarum in the nominal concentration range between 1 and 100 μg/l, BPA induced an enhancement of embryo production even in the sexual repose phase of the reproductive cycle. A characteristic inverted U-type concentration response relationship was found. Nassarius reticulatus was exposed via BPA-spiked artificial sediments (nominal concentration range: 10–1000 μg/kg dry wt.) for 3 months. BPA exhibited a significant and concentration dependent uterotrophic effect which could be detected not only by an enlargement but also by a weight increase of the accessory pallial gland complex in the pallial oviduct section. Adult Nucella lapillus were tested for three months in the laboratory in a nominal concentration range between 1 and 100 μg BPA/l. Superfemales in the dog whelk were also characterised by enlarged accessory pallial sex glands and an enhancement of egg production, but the test compound also affected the males in this species. A lower percentage of exposed specimens had ripe sperm stored in their vesicula seminalis and male Nucella exhibited a reduced length of penis and prostate gland when compared to the control. Because statistically significant effects were observed already at the lowest nominal test concentration (1 μg/l), it can be assumed that even lower concentrations may have a negative impact on the snails. The results show that prosobranch snails are affected by BPA at lower concentrations compared to other systematic taxa in the animal kingdom. Consequently, it has to be claimed that the results of these experiment have to be considered for the current EU risk assessment for BPA in order to achieve a sufficient protection of wildlife in aquatic ecosystems.     

Detection and Classification of Motor Vehicle Noise in a Forested Landscape

Noise emanating from human activity has become a common addition to natural soundscapes and has the potential to harm wildlife and erode human enjoyment of nature. In particular, motor vehicles traveling along roads and trails produce high levels of both chronic and intermittent noise, eliciting varied responses from a wide range of animal species. Anthropogenic noise is especially conspicuous in natural areas where ambient background sound levels are low. In this article, we present an acoustic method to detect and analyze motor vehicle noise. Our approach uses inexpensive consumer products to record sound, sound analysis software to automatically detect sound events within continuous recordings and measure their acoustic properties, and statistical classification methods to categorize sound events. We describe an application of this approach to detect motor vehicle noise on paved, gravel, and natural-surface roads, and off-road vehicle trails in 36 sites distributed throughout a national forest in the Sierra Nevada, CA, USA. These low-cost, unobtrusive methods can be used by scientists and managers to detect anthropogenic noise events for many potential applications, including ecological research, transportation and recreation planning, and natural resource management.     

Scales of integration for sustainable development governance

Efforts at integration are central in the Sustainable Development Goals and the wider Post-2015 Sustainable Development Agenda. While integration forms a major focus of this agenda, there are fundamental limitations on pursuing this focus. The global governance discussions on integration lack a clear conceptualization of what it is, do not have any tools for measurement or assessment, and are narrowly focused around policy integration between global institutions. This article develops a framework for conceptualizing cross-level and cross-scale integration which addresses these problems and introduces the opportunities and challenges of pursuing different types of integration in global governance. Cross-level integration involves governance efforts which seek to bridge similar institutions with one another (for example, bringing together efforts by environmental ministries and development ministries). Cross-scale integration, in contrast, deals with governance efforts that bring together institutions which have distinct scopes, jurisdictions, and epistemologies. With this important distinction, the article explores the opportunities for cross-scale integration as part of the global sustainable development efforts and particularly expanding the policy integration focus with spatial and temporal integration as well. The conclusion uses the Earth System Governance perspective to focus on the trade-offs that are likely as wider forms of institutional integration are pursued beyond environmental mainstreaming and policy integration.     

Nutrient attenuation by a riparian wetland during natural and artificial runoff events

Due to chronic nutrient enrichment of surface water, wetlands adjacent to land managed with fertilizer have been studied to determine their role in nutrient dynamics. We sampled golf course runoff and determined the loads of NO3- and PO4(-3) transported during storms and the attenuation of those loads when runoff passed through a riparian wetland. All sampled storm events contained NO3- (2 to 1470 g NO3-N per event) and PO4(-3) (1 to 4156 g PO4-P per event). Extensive nutrient attenuation occurred when water passed through the riparian wetland. In 11 events, NO3- and PO4(-3) attenuation averaged 80 and 74%, respectively. In subsequent experiments, we created a stream of water flowing into the wetland and amended it with NO3-, PO4(-3) and Br-, creating an artificial runoff event. The experiments were conducted using conditions similar to those of natural runoff events. We observed rapid and complete attenuation of PO4(-3) immediately after runoff water infiltrated into the wetland subsurface. No PO4(-3) was observed in discharge from the wetland. Nitrate attenuation occurred following a lag phase of several hours that was probably due to reactivation of denitrifying enzymes. Nitrate attenuation was initially less than 60% but increased to 100% in all experiments. We observed extensive dilution of runoff water in the wetland subsurface indicating mixing with pre-event ground water in the wetland. The results indicated that intermittent inputs of NO3- and PO4(-3) could be successfully attenuated in the wetland on the time scale of natural storm events.     

Changes in HIV/AIDS/STI knowledge, attitudes and practices among commercial sex workers and military forces in Port Loko, Sierra Leone

Sierra Leone suffered from 11 years of civil war (1991-2002) resulting in tens of thousands of deaths and mutilations together with massive population displacement. In 2001, ARC International, Sierra Leone conducted a baseline survey of 201 commercial sex workers (CSWs) and 202 military respondents on the knowledge, attitudes and practices surrounding HIV/AIDS and STIs in Port Loko, Sierra Leone. In 2003, a comparable post-intervention survey of 202 CSWs and 205 military respondents was performed. Comparison of baseline and post-intervention results showed that HIV/AIDS knowledge increased among both groups, with those able to name three effective means of avoiding AIDS increasing from 5 per cent to 70 per cent among CSWs, and 11 to 75 per cent among the military. Reported condom use during last sex increased among CSWs from 38 to 68 per cent and among military from 39 to 68 per cent. These results demonstrate that, despite the challenges inherent in a post-conflict country, good-quality AIDS-prevention programmes can be effective.     

Power and Sample Size Calculations for Linear Hypotheses Associated with Mixtures of Many Components using Fixed-Ratio Ray Designs

Response surface methodology, often supported by factorial designs, is the classical experimental approach that is widely accepted for detecting and characterizing interactions among chemicals in a mixture. In an effort to reduce the experimental effort as the number of compounds under study is increased, ray designs have been proposed to study combinations of chemicals. When interest is restricted to relevant mixing ratios, we are only interested in making inference along the specific rays of interest, as opposed to methods which use designs that require more experimental effort to support the estimation of a response surface over a broader experimental region. Methods have been developed for the test of additivity along multiple fixed-ratio rays. Of primary importance is the detection of interactions with reasonable power. The objective of this paper is to address power and sample size issues related to the hypothesis of no interaction.