Parasites in a Changing World: Troublesome or in Trouble?

Consequent Effects of Parasitism on Population Dynamics, Food Webs, and Human Health Under Climate Change

Understanding the long-term effects of ongoing global environmental change on marine ecosystems requires a cross-disciplinary approach. Deep-time and recent fossil records can contribute by identifying traits and environmental conditions associated with elevated extinction risk during analogous events in the geologic past and by providing baseline data that can be used to assess historical change and set management and restoration targets and benchmarks. Here, we review the ecological and environmental information available in the marine fossil record and discuss how these archives can be used to inform current extinction risk assessments as well as marine conservation strategies and decision-making at global to local scales. As we consider future research directions in deep-time and conservationpaleobiology, we emphasize the need for coproduced research that unites researchers, conservation practitioners, and policymakers with the communities for whom the impacts of climate and global change are most imminent.

Taxonomic and geographic bias in the genetic study of helminth parasites

Population response to global change will depend on responses to a multivariate set of changes in abiotic habitat characteristics and biotic interactions. Organismal biologists seeking to make ecological inferences about the impacts of global change by studying physiological performance have traditionally performed carefully controlled experimental studies that examine one variable at a time. Those studies, while of high value, may not lead to accurate predictions of organismal responses in the natural habitat, where organisms experience concomitant changes in multiple environmental factors. The symposium "Physiological Responses to Simultaneous Shifts in Multiple Environmental Stressors: Relevance in a Changing World" focused on physiological studies in which multiple environmental variables were simultaneously examined and brought together an international group of early-career and established speakers with unique perspectives on studies of multistressors. In doing so, the objective of the symposium was to frame the necessary next steps for increasing predictive capacity of organismal responses to environmental shifts in the natural habitat, establish novel collaborations among researchers actively investigating physiological responses to a multivariate environment, and broaden the number of researchers conducting such studies.

Influencing mechanism of climate and human activities on ecosystem health in the middle reaches of the Yellow River of China

A meta-analysis of soil extracellular enzyme activities in response to global change

Water security is one of the main paradigms presently shaping global water governance. At its very core, water security aims at preserving freshwater resources from any form of risk, natural or human-caused, that could imperil or further delay the stability and the sustainability of societies and ecosystems. The adoption of the Sustainable Development Goals has acknowledged this paradigm as a key avenue towards the alleviation of poverty, the promotion of gender equality, the universal access to sanitation, and the protection of natural environments. However, reaching a universal water secure state, a harsh endeavor in itself, has been further complicated by the pervasive effects of global environmental change, among which widespread climate anomalies and population growth represent the main hurdles. The instability caused by environmental change has led to the emergence of risk situations that have never been encountered before and for which global analysis tools and governance strategies have yet to be designed. Wildland fires are one of the most important natural drivers of vegetation dynamics at the surface of the globe. In many parts of the world, global environmental change has led to more conducive fire weather patterns combined with a higher ignition frequency due to landscape anthropization. This situation has increased the occurrence, extent, and severity of catastrophic wildfires in many areas critical for the provision of surface freshwater supplies to downstream human and natural communities. Although fire-caused alterations of the hydrological cycle have been recognized for a long time, the upsurge of extensive and severe blazes in many basinsâ headwaters has shed light on the exposure of downstream populations and aquatic ecosystems to post-fire hydrogeomorphic hazards, such as floods or nutrient pollution. Exposed assets are therefore made vulnerable to harmful consequences such as the degradation of environmental flows, the disruption of the drinking-water supply, or the destruction of infrastructures. The emergence of wildfire-related risks to freshwater resources is thus becoming a new challenge to add to the long list of threats to water security, and solving this issue will not be done without innovative research efforts. The research presented hereafter offers the first global exploration of wildfire risks to water security. The resulting work offers three main outcomes. First, it widens the water security paradigm by demonstrating the growing danger that wildfires represent to the freshwater supply. Secondly, it provides an efficient and highly flexible risk analysis framework to researchers, managers, and policy-makers involved in the resolution of water security matters and the design of disaster risk reduction strategies. Finally, it proposes a reflection on the deleterious, though often overlooked, emerging effects of global environmental change affecting the interactions between fire activity and the hydrologic cycle. This work will hopefully help to better guide global water governance by acknowledging the extensive and potentially dangerous effects of wildfires on socio-hydrological systems.

Examination of 5,456 fish of 36 different species during 1951 and 1952 showed 4,925 or 90 per cent to be infected with at least one species of parasite. Records include fish from many lakes and streams of the Columbia and Fraser drainages and from a few localities in the Skeena, Peace, Liard and Skagit drainages. Parasites are recorded for each species of fish from each locality. The incidence of parasitism in the fish was comparable with that found by other surveys in eastern Canada and the United States. No major differences were found in the parasite faunas of the different river systems. Most of the common parasites were forms of circumpolar or general North American distribution. Several species of parasites described only from the Pacific coast area were common in certain hosts. Introduced species of fish showed very light infections with but few species of their normal parasites. The parasite fauna of fishes of this area appears to be less varied than in eastern and southern parts of the continent.

We analyze the dynamics of a community of macroparasite species that share the same host. Our work extends an earlier framework for a host species that would grow exponentially in the absence of parasitism, to one where an uninfected host population is regulated by factors other than parasites. The model consists of one differential equation for each parasite species and a single density-dependent nonlinear equation for the host. We assume that each parasite species has a negative binomial distribution within the host and there is zero covariance between the species (exploitation competition). New threshold conditions on model parameters for the coexistence and competitive exclusion of parasite species are derived via invadibility and stability analysis of corresponding equilibria. The main finding is that the community of parasite species coexisting at the stable equilibrium is obtained by ranking the species according t! o th e minimum host density H* above which a parasite species can grow when rare: the lower H*, the higher the competitive ability. We also show that ranking according to the basic reproduction number Q0 does not in general coincide with ranking according to H*. The second result is that the type of interaction between host and parasites is crucial in determining the competitive success of a parasite species, because frequency-dependent transmission of free-living stages enhances the invading ability of a parasite species while density-dependent transmission makes a parasite very sensitive to other competing species. Finally, we show that density dependence in the host population entails a simplification of the portrait of possible outcomes with respect to previous studies, because all the cases resulting in the exponential growth of host and parasite populations are eliminated..

SUMMARY Molecular phylogeography has revolutionised our ability to infer past biogeographic events from cross-sectional data on current parasite populations. In ecological parasitology, this approach has been used to address fundamental questions concerning host-parasite co-evolution and geographic patterns of spread, and has raised many technical issues and problems of interpretation. For applied parasitologists, the added complexity inherent in adding population genetic structure to perceived parasite distributions can sometimes seem to cloud rather than clarify approaches to control. In this paper, we use case studies firstly to illustrate the potential extent of cryptic diversity in parasite and parasitoid populations, secondly to consider how anthropogenic influences including movement of domestic animals affect the geographic distribution and host associations of parasite genotypes, and thirdly to explore the applied relevance of these processes to parasites of socio-economic importance. The contribution of phylogeographic approaches to deeper understanding of parasite biology in these cases is assessed. Thus, molecular data on the emerging parasites Angiostrongylus vasorum in dogs and wild canids, and the myiasis-causing flies Lucilia spp. in sheep and Cochliomyia hominovorax in humans, lead to clear implications for control efforts to limit global spread. Broader applications of molecular phylogeography to understanding parasite distributions in an era of rapid global change are also discussed.

The pace and scale of environmental change is undermining the conditions for human health. Yet the environment and human health remain poorly integrated within research, policy and practice. The ecosystem services (ES) approach provides a way of promoting integration via the frameworks used to represent relationships between environment and society in simple visual forms. To assess this potential, we undertook a scoping review of ES frameworks and assessed how each represented seven key dimensions, including ecosystem and human health. Of the 84 ES frameworks identified, the majority did not include human health (62%) or include feedback mechanisms between ecosystems and human health (75%). While ecosystem drivers of human health are included in some ES frameworks, more comprehensive frameworks are required to drive forward research and policy on environmental change and human health.Electronic supplementary materialThe online version of this article (doi:10.1007/s10393-015-1041-4) contains supplementary material, which is available to authorized users.

FACE‐ing the facts: inconsistencies and interdependence among field, chamber and modeling studies of elevated [CO₂] impacts on crop yield and food supply

Preface. Changes in Atmospheric Circulation and Climate over the North Atlantic and Europe T.D. Davies, et al. Linkages Between Atmospheric Weather and the Dynamics of Limnetic Phytoplankton C.S. Reynolds. The Influence of Weather Conditions on the Seasonal Plankton Development in a Large and Deep Lake (L. Constance): I. The Impact of Irradiance, Air Temperature and Wind on the Algal Spring Development - An Analysis Based on Long-Term Measurements U. Gaedke, et al. II. Water Column Stability Derived from One-Dimensional Hydrodynamical Models D. Ollinger, E. Bauerle. III. The Impact of Water Column Stability on Spring Algal Development U. Gaedke, et al. IV. The Response of Crustacean Zooplankton to Variations in Water Temperature and Algal Growth in Spring and Early Summer D. Straile, W. Geller. Fluctuations of Phytoplankton Production and Chlorophyll Concentrations in a Small Humic Lake During Six Years (1990-1995) J. Keskitalo, K. Salonen. Sudden and Gradual Responses of Phytoplankton to Global Climate Change: Case Studies from Two Large, Shallow Lakes (Balaton, Hungary, and the Neusiedlersee, Austria/Hungary) J. Padisak. Impact of Climate-Affected Flowrates on Phytoplankton Dynamics in Dam Reservoirs B. Desortova, P. Puncochar. Managing Reservoir Water Quality in the Vltava River Board Area J. Duras. The Mass Invasion of Several Blue-Green Algae in Two Drinking-Water Supply Reservoirs in Southern Poland H. Bucka. Water Quality in the Lakes and Reservoirs of Romania T.L. Constantinescu. Long-Term Variation of Chlorophyll Content in Rybinsk Reservoir (Russia) in Relation to its Hydrological Regime N.M. Mineeva, A.S. Litvinov. Long-Term Hydrobiological Investigations on Lakes in Northwest Russia V.G.Drabkova, et al. The Timing of Warming -- An Important Regulator of Change in Lake Plankton Communities R. Adrian. The Influence of Year-to-Year Changes in Position of the Atlantic Gulf Stream on the Biomass of Zooplankton in Windermere North Basin, UK D.G. George, D.P. Hewitt. Environmental Factors Influencing the Recruitment and Growth of Underyearling Perch (Perca fluviatilis) in Windermere North Basin, UK, from 1966 to 1990 I.J. Winfield, et al. Fluctuations in Lake Fisheries and Global Warming D. Gerdeaux. Interannual Synchronous Dynamics in North Temperate Lakes in Wisconsin, USA T.K. Kratz, et al. Working Group Topic 1: Modelling the Responses of Lakes to Day-to-Day Changes in Weather C.S. Reynolds, et al. Working Group Topic 2: Detecting and Predicting the Responses of Lakes to Global Climate Change U. Gaedke, et al. Working Group Topic 3: Managing Water Quality in a Changing World D.G. George, et al. Working Group Topic 4: International Networks of Lake Sites T.K. Kratz, et al. Index.

Discursive Resilience

Biological invasion has become one of the great threats to ecosystems worldwide. Frequently, invasion is caused by anthropogenic activities either intentionally due to an introduction of free-living organisms for agricultural or recreational purposes as well as unintentionally for instance if species are transported unperceived in cargo containers from one ecosystems to another. However, only a small amount of these species will be able to establish itself after entering a new habitat. As soon as a species is successful they might become invasive and cause negative effects to local biocoenosis that might lead to loss of biodiversity or eventually initiate a meltdown of the entire system. Biological invasion is a global problem, which is exacerbated inter alia by globalization, (wrong) environmental management and climate change. In that context Europe have become one of the hotspot for invasion where various Ponto-Caspian species that are considered very successful invaders established many self-sustaining communities. Ponto-Caspian (PC) species such as the zebra mussel, killer shrimp (Dikerogammarus villosus), round-, bighead-, and monkey goby usually adapt easily to environmental conditions and frequently become dominant species in newly invaded habitats. Additionally various PC species seem to favor the distribution of pathogens and parasites. However, these relatively new discovery are scarcely studied, which represents a general problem in the research of invasion biology since the effects of invasive species on parasites are frequently neglected. The ignorance towards parasites is surprising because they are considered as important response variable for ecosystems health. Generally, parasites contribute to 40 % of the biomass of an ecosystem, govern host behavior, and potentially alter the structure, dynamics and function of food webs.Therefore, the effects of invasion by the example of PC invasive species on local parasite communities were at the focus of the present doctoral thesis. Hence, their impact on parasite prevalence and infestation intensities within various hosts of habitats that were free of or invaded by PC species were compared and evaluated. Additionally, possible interactions of co-introduced PC parasites with local parasites and the consequences for local species were investigated. Thus, within a period of four years three local and one PC fish hosts as well as two different amphipod species were sampled in various rivers (in Germany, the Netherlands, Switzerland) and parasitological examined. The results were compared with each other and subsequently placed into context. The results of various substudies showed that PC species affect the parasite communities of recently invaded habitats on many layers. In this context, the acanthocephalan Pomphorhynchus laevis and the nematode Raphidascaris acus have been identified as key species since an increase in their prevalence in local hosts seem to be related to PC invasion. Furthermore, the interaction between P. laevis and other PC species might have caused the replacement of the local acanthocephalan P. tereticollis in invaded habitats and eventually directly encouraged interactions between P. laevis and other local parasites. The results of the present doctoral thesis have shown that effects of PC invasive species on parasites are multilayered and therefore suggest that not only PC species but invasive species in general might affect local parasite communities. Hence, parasites have to be integrated into proposed or existing conservation efforts, since invasive species might cause an increase of local parasites and/or a loss of parasite diversity, both with grave consequences for local environments.