Micael Jonsson

Higher levels of multiple ecosystem services are found in forests with more tree species

Forests are of major importance to human society, contributing several crucial ecosystem services. Biodiversity is suggested to positively influence multiple services but evidence from natural systems at scales relevant to management is scarce. Here, across a scale of 400,000 km2, we report that tree species richness in production forests shows positive to positively hump-shaped relationships with multiple ecosystem services. These include production of tree biomass, soil carbon storage, berry production and game production potential. For example, biomass production was approximately 50% greater with five than with one tree species. In addition, we show positive relationships between tree species richness and proxies for other biodiversity components. Importantly, no single tree species was able to promote all services, and some services were negatively correlated to each other. Management of production forests will therefore benefit from considering multiple tree species to sustain the full range of benefits that the society obtains from forests.

Dilute Concentrations of a Psychiatric Drug Alter Behavior of Fish from Natural Populations

Unintended Recipients of Antidepressants Pharmaceuticals are used to treat a wide variety of ailments and conditions in humans. However, many animal species share physiologies, receptors, and pathways that may be acted upon by pharmaceutical compounds. Increasingly, pharmaceuticals are being found in natural aquatic systems. Such pharmaceutical pollution can cause mortality and alter development and reproduction of aquatic animals. Brodin et al. (p. 814) report that excreted drugs may also have far more subtle, yet eventually significant, impacts in natural systems. Benzodiazepines, which reduce anxiety in humans, alter social and foraging behavior in fish. European perch exposed to oxazepam were bolder, more active, less social and fed more rapidly. Anxiolytic drugs, at concentrations found in natural waterways, alter the behavior and foraging rate of wild European perch. Environmental pollution by pharmaceuticals is increasingly recognized as a major threat to aquatic ecosystems worldwide. A variety of pharmaceuticals enter waterways by way of treated wastewater effluents and remain biochemically active in aquatic systems. Several ecotoxicological studies have been done, but generally, little is known about the ecological effects of pharmaceuticals. Here we show that a benzodiazepine anxiolytic drug (oxazepam) alters behavior and feeding rate of wild European perch (Perca fluviatilis) at concentrations encountered in effluent-influenced surface waters. Individuals exposed to water with dilute drug concentrations (1.8 micrograms liter–1) exhibited increased activity, reduced sociality, and higher feeding rate. As such, our results show that anxiolytic drugs in surface waters alter animal behaviors that are known to have ecological and evolutionary consequences.

Ecological effects of pharmaceuticals in aquatic systems—impacts through behavioural alterations

The study of animal behaviour is important for both ecology and ecotoxicology, yet research in these two fields is currently developing independently. Here, we synthesize the available knowledge on drug-induced behavioural alterations in fish, discuss potential ecological consequences and report results from an experiment in which we quantify both uptake and behavioural impact of a psychiatric drug on a predatory fish (Perca fluviatilis) and its invertebrate prey (Coenagrion hastulatum). We show that perch became more active while damselfly behaviour was unaffected, illustrating that behavioural effects of pharmaceuticals can differ between species. Furthermore, we demonstrate that prey consumption can be an important exposure route as on average 46% of the pharmaceutical in ingested prey accumulated in the predator. This suggests that investigations of exposure through bioconcentration, where trophic interactions and subsequent bioaccumulation of exposed individuals are ignored, underestimate exposure. Wildlife may therefore be exposed to higher levels of behaviourally altering pharmaceuticals than predictions based on commonly used exposure assays and pharmaceutical concentrations found in environmental monitoring programmes.

Simulating species loss following perturbation: assessing the effects on process rates

We removed stream-living macroinvertebrate shredder species in the sequences in which they are predicted to disappear, in response to two common types of anthropogenic disturbances: acidification and organic pollution, and analysed the effects on leaf breakdown rates. The experiment was performed in field microcosms using three shredder species. Species identity significantly affected leaf breakdown rates, while species richness per se was non–significant. The simulated sequential species loss showed large effects on leaf breakdown rates, with observed rates being significantly higher than expected from single–species treatments in two, out of four, two–species, and in all four three-species treatments. The invertebrates used in this study were taxonomically distinct (Insecta: Plecoptera and Trichoptera; Crustacea: Amphipoda), and of different sizes, hence a high degree of complementarity was probably present. A method to study the effects of species loss, characteristic of perturbation type, could be more useful than a random approach when investigating the impact of perturbation. Our results may have general applicability for investigations on the effects of diversity loss on ecosystem functioning in any ecosystem exposed to human perturbations, given that the order of extinction is known or can easily be assessed.

Structural equation modelling reveals plant- community drivers of carbon storage in boreal forest ecosystems

Boreal forest ecosystems are important drivers of the global carbon (C) cycle by acting as both sinks and sources of atmospheric CO2. While several factors have been proposed as determining the ability of boreal forest to function as C sinks, little is known about their relative importance. In this study, we applied structural equation modelling to a previously published dataset involving 30 boreal-forested islands that vary greatly in their historic fire regime, in order to explore the simultaneous influence of several factors believed to be important in influencing above-ground, below-ground and total ecosystem C accumulation. We found that wildfire was a major driver of ecosystem C sequestration, and exerted direct effects on below-ground C storage (presumably through humus combustion) and indirect effects on both above-ground and below-ground C storage through altering plant-community composition. By contrast, plant diversity influenced only below-ground C storage (and even then only weakly), while net primary productivity and decomposition had no detectable effect. Our results suggest that while boreal forests have great potential for storing significant amounts of C, traits of dominant plant species that promote below-ground C accumulation and the absence of wildfire are the most important drivers of C sequestration in these ecosystems.

Species richness and composition effects in a detrital processing chain

Abstract Several studies in the past decade have shown that rates of ecosystem processes may be affected by the number of species involved in the processes. However, how products, such as frass and feces, that are derived from those processes indirectly affect other functional feeding groups (FFGs) and whether such effects vary with species number are not well understood. We manipulated presence/absence and species richness of shredding larval stoneflies in laboratory microcosms containing leaf litter to test whether the number of species affected the growth of suspension-feeding black fly larvae. The presence of shredders increased the production of particles (>0.1 mm) and contributed to 30 to 56% higher black fly growth than in the absence of shredders. In addition, species richness and composition of shredders significantly affected black fly growth. Thus, our results show that species richness and composition in one FFG may affect FFGs further down the processing chain, most likely via effects on both quantity and size distribution of products derived from the process.

The conceptual imperfection of aquatic risk assessment tests: highlighting the need for tests designed to detect therapeutic effects of pharmaceutical contaminants

Standardized ecotoxicological tests still constitute the fundamental tools when doing riskassessment of aquatic contaminants. These protocols are managed towards minimal mortality in the controls, which is not representative for natural systems where mortality is often high. This methodological bias, generated from assays where mortality in the control group is systematically disregarded, makes it difficult to measure therapeutic effects of pharmaceutical contaminants leading to lower mortality. This is of concern considering that such effects on exposed organisms still may have substantial ecological consequences. In this paper, we illustrate this conceptual problem by presenting empirical data for how the therapeutic effect of Oxazepam—a common contaminant of surface waters—lower mortality rates among exposed Eurasian perch (Perca fluviatilis) from wild populations, at two different life stages. We found that fry hatched from roe that had been exposed to dilute concentrations (1.1±0.3 μgl �1 )o f Oxazepam for 24 h 3–6 days prior to hatching showed lower mortality rates and increased activity 30 days after hatching. Similar effects, i.e. increased activity and lower mortality rates were also observed for 2-year old perch exposed to dilute Oxazepam concentrations (1.2±0.4 μgl �1 ). We conclude that therapeutic effects from pharmaceutical contaminants need to be considered in risk assessment assays to avoid that important ecological effects from aquatic contaminants are systematically missed. S Online supplementary data available from stacks.iop.org/ERL/9/084003/mmedia

Antihistamines and aquatic insects: Bioconcentration and impacts on behavior in damselfly larvae (Zygoptera)

Because aquatic insects use histamines as neurotransmitters, adverse impacts on aquatic insects living in aquatic environments that receive antihistamines with wastewater effluent are plausible. In this study, we exposed damselfly larvae to low concentrations of two commonly used antihistamines (Hydroxyzine and Fexofenadine, 360 ± 42 and 2,200 ± 43 ng l(-1), respectively), and recorded damselfly larvae behavior before and after exposure. Further, after the second set of behavioral assays was performed, we quantified bioconcentration of the antihistamines in the damselfly bodies. Our results showed significant changes in damselfly behavior following antihistamine exposure. After Hydroxyzine exposure, the damselfly larvae became less active, and they showed reduced fleeing response (i.e. increased boldness) after being exposed to Fexofenadine, the latter also being significantly different from the non-exposed (control) individuals. Further, we found high levels of bioconcentration in the damselflies; Hydroxyzine showed an average bioconcentration factor (BCF) of 2000. As such, our results indicate that low concentrations of antihistamines can have sub-lethal effects on aquatic insects manifested as behavioral changes, and that bioconcentration of these substances can be high. Therefore, the need to investigate the impact of emergent aquatic contaminants also on aquatic insects, and on behaviors that are of ecological importance, is further highlighted.

Bioaccumulation of five pharmaceuticals at multiple trophic levels in an aquatic food web - Insights from a field experiment.

Pharmaceuticals derived from manufacturing and human consumption contaminate surface waters worldwide. To what extent such pharmaceutical contamination accumulates and disperses over time in different compartments of aquatic food webs is not well known. In this study we assess to what extent five pharmaceuticals (diphenhydramine, oxazepam, trimethoprim, diclofenac, and hydroxyzine) are taken up by fish (European perch) and four aquatic invertebrate taxa (damselfly larvae, mayfly larvae, waterlouse, and ramshorn snail), by tracing their bioconcentrations over several months in a semi-natural large-scale (pond) system. The results suggest both significant differences among drugs in their capacity to bioaccumulate and differences among species in uptake. While no support for in situ uptake of diclofenac and trimethoprim was found, oxazepam, diphenhydramine, and hydroxyzine were detected in all analyzed species. Here, the highest bioaccumulation factor (tissue:water ratio) was found for hydroxyzine. In the food web, the highest concentrations were found in the benthic species ramshorn snail and waterlouse, indicating that bottom-living organism at lower trophic positions are the prime receivers of the pharmaceuticals. In general, concentrations in the biota decreased over time in response to decreasing water concentrations. However, two interesting exceptions to this trend were noted. First, mayfly larvae (primarily grazers) showed peak concentrations (a fourfold increase) of oxazepam, diphenhydramine, and hydroxyzine about 30days after initial addition of pharmaceuticals. Second, perch (top-predator) showed an increase in concentrations of oxazepam throughout the study period. Our results show that drugs can remain bioavailable for aquatic organism for long time periods (weeks to months) and even re-enter the food web at a later time. As such, for an understanding of accumulation and dispersion of pharmaceuticals in aquatic food webs, detailed ecological knowledge is required.

Long-Term Persistence of an Anxiolytic Drug (Oxazepam) in a Large Freshwater Lake

Production and human consumption of pharmaceuticals result in contamination of surface waters worldwide. Little is known about the long-term (i.e., over decades) fate of pharmaceuticals in aquatic systems. Here, we show that the most prescribed anxiolytic in Sweden (oxazepam) persists in its therapeutic form for several decades after being deposited in a large freshwater lake. By comparing sediment cores collected in 1995 and 2013, we demonstrate that oxazepam inputs from the early 1970s remained in the sediments until sampling in 2013, despite in situ degradation processes and sediment diagenesis. In laboratory and pond experiments, we further reveal that therapeutic forms of oxazepam can persist over several months in cold (5 °C) lake water free from UV light. We conclude that oxazepam can persist in lakes over a time scale much longer than previously realized and that levels can build up in lakes due to both a legacy of past inputs and a growing urban population.