Effects of a glyphosate-based herbicide on mate location in a wolf spider that inhabits agroecosystems

Chemical communication is important to many arthropod species but the potential exists for anthropogenic chemicals to disrupt information flow. Although glyphosate-based herbicides are not acutely toxic to arthropods, little is known regarding their effects on natural chemical communication pathways. The wolf spider, Pardosamilvina, is abundant in agroecosystems where herbicides are regularly applied and uses air- and substrate-borne chemical signals extensively during mating. The aim of this study was to examine effects of a commercial formulation of a glyphosate-based herbicide on the ability of males to find females. In the field, virgin females, when hidden inside pitfall traps with herbicide, attracted fewer males than females with water. Likewise females in traps with a ring of herbicide surrounding the opening were less likely to attract males than those in traps surrounded by water. We explored the reaction of males to any airborne component of the herbicide in a laboratory two-choice olfactometer experiment. When no female pheromones were present, males were equally likely to select herbicide or water treated corridors and they all moved through the apparatus at similar speeds. When female pheromones were present, the males that selected control corridors moved more slowly than those that selected herbicide and, if we control for the initial decision time, more males selected the control corridors over the herbicide. These data suggest that glyphosate-based herbicides are “info-disruptors” that alter the ability of males to detect and/or react fully to female signals.     

A framework for understanding climate change impacts on coral reef social–ecological systems

Corals and coral-associated species are highly vulnerable to the emerging effects of global climate change. The widespread degradation of coral reefs, which will be accelerated by climate change, jeopardizes the goods and services that tropical nations derive from reef ecosystems. However, climate change impacts to reef social–ecological systems can also be bi-directional. For example, some climate impacts, such as storms and sea level rise, can directly impact societies, with repercussions for how they interact with the environment. This study identifies the multiple impact pathways within coral reef social–ecological systems arising from four key climatic drivers: increased sea surface temperature, severe tropical storms, sea level rise and ocean acidification. We develop a novel framework for investigating climate change impacts in social–ecological systems, which helps to highlight the diverse impacts that must be considered in order to develop a more complete understanding of the impacts of climate change, as well as developing appropriate management actions to mitigate climate change impacts on coral reef and people.     

Utilizing international networks for accelerating research and learning in transformational sustainability science

A promising approach for addressing sustainability problems is to recognize the unique conditions of a particular place, such as problem features and solution capabilities, and adopt and adapt solutions developed at other places around the world. Therefore, research and teaching in international networks becomes critical, as it allows for accelerating learning by sharing problem understandings, successful solutions, and important contextual considerations. This article identifies eight distinct types of research and teaching collaborations in international networks that can support such accelerated learning. The four research types are, with increasing intensity of collaboration: (1) solution adoption; (2) solution consultation; (3) joint research on different problems; and (4) joint research on similar problems. The four teaching types are, with increasing intensity of collaboration: (1) adopted course; (2) course with visiting faculty; (3) joint course with traveling faculty; and (4) joint course with traveling students. The typology is illustrated by extending existing research and teaching projects on urban sustainability in the International Network of Programs in Sustainability, with partner universities from Europe, North America, Asia, and Africa. The article concludes with challenges and strategies for extending individual projects into collaborations in international networks.     

Investigations of mercury concentrations in walleye and other fish in the Athabasca River ecosystem with increasing oil sands developments

Recent studies have reported an increasing trend of mercury concentrations in walleye (Sander vitreus) from the Athabasca River, north eastern Alberta (Canada); these studies were based on three years of comparison and attributed the mercury increase to expanding oil sands developments in the region. In order to conduct a more comprehensive analysis of mercury trends in fish, we compiled an extensive database for walleye, lake whitefish (Coregonus clupeaformis), northern pike (Esox lucius) and lake trout (Salvelinus namaycush) using all available data obtained from provincial, federal, and industry-funded monitoring and other programs. Evidence for increasing trends in mercury concentrations were examined for each species by location and year also considering fish weight and length. In the immediate oil sands area of the Athabasca River, mercury concentrations decreased (p < 0.001) in walleye and lake whitefish over 1984-2011. In western Lake Athabasca and its delta, mercury concentrations decreased (p < 0.0001) in northern pike (1981-2009) although no trend was evident for walleye (1981-2005) and lake trout (1978-2009). Mercury concentrations in lake trout from Namur Lake, a small lake west of the oil sands area, were higher in 2007 than 2000 (p < 0.0001); it is difficult to ascribe this increase to an oil sands impact because similar increases in mercury concentrations have been observed in lake trout from similar sized lakes in the Northwest Territories. While mercury emissions rates have increased with oil sands development and the landscape become more disturbed, mercury concentrations remained low in water and sediments in the Athabasca River and its tributaries and similar to concentrations observed outside the development areas and in earlier decades. Our fish database was assembled from a series of studies that differed in study purpose, design, and analytical methods. Future monitoring programs investigating mercury trends in fish should be more rigorous in their design.     

Nutrient dynamics and tree growth of silvopastoral systems: impact of poultry litter

Fertilizing pastures with poultry litter has led to an increased incidence of nutrient-saturated soils, particularly on highly fertilized, well drained soils. Applying litter to silvopastures, in which loblolly pine (Pinus taeda L.) and bahiagrass (Paspalum notatum) production are integrated, may be an ecologically desirable alternative for upland soils of the southeastern USA. Integrating subterranean clover (Trifolium subterraneum) into silvopastures may enhance nutrient retention potential. This study evaluated soil nutrient dynamics, loblolly pine nutrient composition, and loblolly pine growth of an annually fertilized silvopasture on a well drained soil in response to fertilizer type, litter application rate, and subterranean clover. Three fertilizer treatments were applied annually for 4 yr: (i) 5 Mg litter ha(-1) (5LIT), (ii) 10 Mg litter ha(-1) (10LIT), and (iii) an inorganic N, P, K pasture blend (INO). Litter stimulated loblolly pine growth, and neither litter treatment produced soil test P concentrations above runoff potential threshold ranges. However, both litter treatments led to accumulation of several nutrients (notably P) in upper soil horizons relative to INO and unfertilized control treatments. The 10LIT treatment may have increased N and P leaching potential. Subterranean clover kept more P sequestered in the upper soil horizon and conferred some growth benefits to loblolly pine. Thus, although these silvopasture systems had a relatively high capacity for nutrient use and retention at this site, litter should be applied less frequently than in this study to reduce environmental risks.     

Mercury concentrations in wild mink (Mustela vison) and river otters (Lontra canadensis) collected from eastern and Atlantic Canada: relationship to age and parasitism

Total mercury (Hg) concentrations were measured in the fur, brain and liver of wild mink (Mustela vison) and river otters (Lontra canadensis) collected from eastern and Atlantic Canada. Total Hg concentrations in fur were strongly correlated with levels in the brain and liver. There was no difference in tissue concentrations between male and female mink; however, female otters had significantly higher fur, brain and liver Hg levels than males. Similarly, there was not a significant relationship between Hg concentration and age of mink, whereas in otters, Hg concentrations in all three tissues decreased significantly with age. In both species, only a very small percentage of the variability in Hg concentration was explained by age. After adjusting the data for site-to-site differences in Hg levels, Hg concentrations in the fur of mink infected by the parasite, Dioctophyma renale, were found to be significantly higher than Hg levels in uninfected mink.     

Speciation of organotins in polyvinyl chloride pipe via X-ray absorption spectroscopy and in leachates using GC-PFPD after derivatisation

Three different polyvinyl chloride (PVC) pipe types were subjected to de-ionized water exposures over the course of at least 180 days. Water exposed to the pipe was analyzed for organotin speciation and concentration. Organotin concentrations were the highest during the first 1-5 days. The species and concentrations of organotins leached varied by pipe type. Data were normalized by surface area in order to compare laboratory results with results from a residential pipe system. For one pipe type, the lowest non-zero concentrations from the laboratory tests overestimated organotin concentrations in solution when compared with water samples from the same pipe type in a residence. For organotin exposure estimates, a range of 0.1 ng m(-2) to 10 ng m(-2) could be used for mature pipes (e.g. in use for 1 year). These estimates should be refined with more field study, however, due to the high variation in organotin species and concentrations leached as a function of pipe type, accuracy within an order of magnitude may be optimal as, in many instances, the type of pipe installed or buried may be unknown. X-ray absorption spectroscopy (XAS) was used to identify organic and inorganic tin species in reference materials and the PVC samples. Monobutyl tin was identified as the primary organotin species in the pipes. Results from the XAS analyses also indicate that the technique shows promise for distinguishing between inorganic tin and organotins. Furthermore, organotins may be distinguished between mono-, di-, and tri-ligand species using XAS.     

Ectoparasites of house sparrows (Passer domesticus): an experimental test of the immunocompetence handicap hypothesis and a new model

Conspicuous secondary sexual traits may have evolved as handicap-revealing signals or as badges of status. We present results of an experiment using males of the sexually dimorphic house sparrow (Passer domesticus), that support the idea that the male-specific bib can be both a handicap-revealing signal and a reliable badge indicating the physical condition of the bird. In a test of the immunocompetence handicap hypothesis, wild-caught adult male house sparrows were studied in captivity. Birds implanted with elevated doses of testosterone were more dominant, had higher circulating levels of both testosterone and corticosterone and they also harboured relatively larger ectoparasite loads. Higher parasite loads were also associated with individuals showing lower immunocompetence and larger changes in bib size. A new model for immunocompetence effects in sexual selection is introduced, integrating actions that the hypothalamopituitary axis exerts on gonads, adrenals and the thyroid gland. The ”integrated immunocompetence model” synthesizes both the ”handicap” (i.e. survival-decreasing) and ”badge of status” (i.e. survival- enhancing) models for evolution of secondary sexual traits. Received: 15 May 1999 / Received in revised form: 2 November 1999 / Accepted: 6 November 1999     

Training Captive-Bred or Translocated Animals to Avoid Predators

Abstract: Animal reintroductions and translocations are potentially important interventions to save species from extinction, but most are unsuccessful. Mortality due to predation is a principal cause of failure. Animals that have been isolated from predators, either throughout their lifetime or over evolutionary time, may no longer express appropriate antipredator behavior. For this reason, conservation biologists are beginning to include antipredator training in pre-release preparation procedures. We describe the evolutionary and ontogenetic circumstances under which antipredator behavior may degenerate or be lost, and we use principles from learning theory to predict which elements can be enhanced or recovered by training. The empirical literature demonstrates that training can improve antipredator skills, but the effectiveness of such interventions is influenced by a number of constraints. We predict that it will be easier to teach animals to cope with predators if they have experienced ontogenetic isolation than if they have undergone evolutionary isolation. Similarly, animals should learn more easily if they have been evolutionarily isolated from some rather than all predators. Training to a novel predator may be more successful if a species has effective responses to similar predators. In contrast, it may be difficult to teach proper avoidance behavior, or to introduce specialized predator-specific responses, if appropriate motor patterns are not already present. We conclude that pre-release training has the potential to enhance the expression of preexisting antipredator behavior. Potential training techniques involve classical conditioning procedures in which animals learn that model predators are predictors of aversive events. However, wildlife managers should be aware that problems, such as the emergence of inappropriate responses, may arise during such training.     

Male characteristics, sperm traits, and reproductive success in winter-spawning Celtic Sea Atlantic herring, Clupea harengus

The relationship between sperm characteristics and reproductive success was examined in male herring, Clupea harengus L. Males were categorised as being first-time or repeat spawners on the basis of their age; they were also grouped according to whether their sperm were immediately active and exhibited forward motion on contact with seawater (FM) or had little or only vibratory motion (VM). Unlike the Pacific herring C. pallasii Valencienes, Atlantic herring sperm is usually motile on contact with seawater. The age, weight and gonadosomatic index (testes mass as a percentage of somatic mass = GSI) were measured and used as characteristics for individual fish. Sperm traits measured were (1) adenosine triphosphate (ATP) concentration, (2) sperm count, (3) duration of sperm motility. Reproductive success for each male was estimated from the fertilisation rate and from the length of larvae at hatching. Fertilisation rates for all fish were generally >80%. The ATP concentration of non-activated spermatozoa was negatively correlated with fertilisation rate. Among repeat spawners, fish with higher GSIs produced larvae that were larger at hatching. Although VM sperm fertilised eggs at rates equivalent to fertilisation by FM sperm, the larvae produced by VM sperm were significantly smaller at hatching. Larval length tended to increase in parallel with the duration of sperm motility, but the relationship was not significant in these tests. The results did not indicate any age or size pattern to spawning readiness in male herring. Sperm that are not yet ready to be shed are not fully motile on contact with seawater, but are still capable of fertilising eggs that hatch successfully. There is likely to be a progression of males which come into spawning readiness within a spawning shoal; therefore it is possible that paternal influences would result in a progressive decrease in larval size over the spawning period in winter-spawning Celtic Sea herring. Received: 22 November 1997 / Accepted: 8 June 1998