Suchergebnisse

The enormous biodiversity of tropical freshwater combined with a considerable increase in the construction of reservoirs urges to understand the ecological effects caused by damming. Using rarely available data obtained before (one year) and after (four years) the filling of a hydroelectric plant on the Teles Pires River (Amazon River basin), the effects on abundance, biomass, and diversity of the fish assemblage were evaluated using two complementary approaches: a BACI (before-after-control-impact) design with mixed models and analyses of covariance. Significant Before-After × Control-Impact interactions in abundance, biomass, and species richness were observed, with decreases of abundance and species richness and more stable biomass after filling. Some abundant species, such as Jupiaba polylepis, Jupiaba acanthogaster, Knodus cf. heteresthes, and Moenkhausia lepidura among others, declined in abundance or disappeared from the impact sites. However, temporal and particularly spatial variation independent of damming explained more variation in all the response variables analyzed, including species composition, and analyses of covariance demonstrated general negative trends irrespective of damming. This study illustrates the usefulness of BACI designs to assess the effects of damming but also that other statistical approaches are complementary, given the difficulty of identifying control sites and the short length of most ecological time series. The results also suggest that preserving tributaries upstream of reservoirs and natural regimes of spatial and temporal environmental variation might help to mitigate the impacts of damming in tropical ecosystems ; Financial support was provided by the Spanish Ministry of Science (projects RED 2018-102571-T, and PID 2019-103936 GB-C21) and the Government of Catalonia (ref. 2017 SGR 548)

Solar geoengineering, also known as Solar Radiation Modification (SRM), has been proposed to alter Earth's radiative balance to reduce the effects of anthropogenic climate change. SRM has been identified as a research priority, as it has been shown to effectively reduce surface temperatures, while substantial uncertainties remain around side effects and impacts. Global modeling studies of SRM have often relied on idealized scenarios to understand the physical processes of interventions and their widespread impacts. These extreme or idealized scenarios are not directly policy-relevant and are often physically implausible (such as imposing global solar reduction to counter the warming of an instantaneous quadrupling of CO2). The climatic and ecological impacts of politically relevant and potentially plausible SRM approaches have rarely been modeled and assessed. Nevertheless, commentators and policymakers often falsely assume that idealized or extreme scenarios are proposed solutions to climate change. This paper proposes 18 scenarios that appear to be broadly plausible from political and Earth System perspectives and encompass futures that could be both warnings or perhaps desirable. We place these scenarios into four groups following broader strategic contexts: (1) Global Management; (2) Regional Emergencies; (3) Coordinated Regional Interventions; and (4) Reactive Global Interventions. For each scenario, relevant model experiments are proposed. Some may be performed with existing setups of global climate models, while others require further specification. Developing and performing these model experiments – and assessing likely resulting impacts on society and ecosystems – would be essential to inform public debate and policymakers on the real-world issues surrounding SRM.

The structure of bird population of urbanized areas is determined by the diversity of habitats within the city, the diversity of bird species in suburban biotopes, and regional processes of dispersal of birds closely associated with human settlements. The analysis of the dynamics of the breeding bird species richness in Minsk showed that its formation progressed in different ways. All in all, since 1946, 141 bird species have been recorded nesting (including allegedly) in the territory of Minsk.The breeding bird assemblages is dominated by dendrophilous (45.0 % of all species) as well as wetland and semi-aquatic (29,3 %) bird species, with more than half of all the breeding bird species (50.3 %) associated with trees and shrubs. In different periods, the breeding bird species richness varied, by now, it has noticeably increased (from 77 to 132 species). This happened due to the expansion of the administrative boundaries of the city with the inclusion of bird species of suburban habitats, an increase in the diversity of habitats suitable for bird nesting (for example, the formation of large water bodies) as well as due to active colonization of urban ecosystems by various bird species. At the same time, after 2000, 9 bird species stopped nesting and 17 bird species started nesting. Active processes of synurbization of some bird species on the European continent observed in recent decades have become the reason for the addition of new species to the avifauna in Minsk, although the basis of the current structure of bird population was formed back in 1986–1999. At the same time, the synurbized groups of various bird species may be of autochthonous, allochthonous, or mixed origin.

AbstractFood web research needs to be predictive in order to support decisions system-based conservation. In order to increase predictability and applicability, complexity needs to be managed in such a way that we are able to provide simple and clear results. One question emerging frequently is whether certain perturbations (environmental effects or human impact) have positive or negative effects on natural ecosystems or their particular components. Yet, most of food web studies do not consider the sign of effects. Here, we study 6 versions of the Kelian River (Borneo) food web, representing six study sites along the river. For each network, we study the signs of the effects of a perturbed trophic group i on each other j groups. We compare the outcome of the relatively complicated dynamical simulation model and the relatively simple loop analysis model. We compare these results for the 6 sites and also the 14 trophic groups. Finally, we see if sign-agreement and sign-determinacy depend on certain structural features (node centrality, interaction strength). We found major differences between different modelling scenarios, with herbivore-detritivore fish behaving in the most consistent, while algae and particulate organic matter behaving in the least consistent way. We also found higher agreement between the signs of predictions for trophic groups at higher trophic levels in sites 1–3 and at lower trophic levels in site 4–6. This means that the behaviour of predators in the more natural sections of the river and that of producers at the more human-impacted sections are more consistently predicted. This suggests to be more careful with the less consistently predictable trophic groups in conservation management.

AbstractBats have been proposed as reliable bioindicators for monitoring bioaccumulation of elements and chemicals in natural and transformed ecosystems. Non-invasive methods are becoming more popular as research moves away from destructive methodologies. We present the first concentrations of 23 elements in Mops condylurus and Tadarida aegyptiaca (Molossidae) fur and blood from an opencast diamond mine and reference area using inductively coupled plasma mass spectrometry (ICP-MS). Concentrations of B, K, Rb and Cd in the bats' fur were significantly higher in the mining footprint compared to the reference area (P < 0.05). Other elements such as Zn and Hg were significantly higher in the blood of bats from the mining footprint than the reference area (P < 0.05), whereas Mn was significantly higher in the blood of bats from the reference area than from the mining footprint (P < 0.05). Sixteen of the 22 elements above the limit of detection, with the exception of Ba, were significantly higher in the fur samples than in the blood due to elements being incorporated over time into the fur as it grows, whereas blood reveals short-term exposure to elements. Concentrations of most of the elements were reasonably low except Al, Fe and Zn. In general, the element concentrations particularly in the fur samples were comparable with other international studies reporting elemental fur concentrations from anthropogenically impacted and natural areas. Fur and blood have the potential to be viable indicators of environmental toxicity, but research is required on toxic thresholds and physiological and ecological unknowns around element concentrations in bat tissues and organs.

AbstractSacred groves are relict forests dedicated to local deities that have been informally protected and managed by local communities over centuries. To gain greater insights into underlying sociocultural reasons for protection, and possibilities of strengthening such efforts, a study has been undertaken in 66 sacred groves in the Maharashtra State of Western Ghats biodiversity hot-spot in India, which shows different facets of human-nature relationships. Primary data on size, ownership, deity, religious aspects and awareness amongst the local people was collected through site visits, semi-structured interviews, and by participating in village meetings. It was observed that village councils owned 48% of the groves as against temple trusts (41%) and forest department plus individually owned groves (11%). Nearly 52% of the groves have an area less than one-half hectare. Forty-seven percent of the groves have male deities, 29% female deities and 26% were dedicated to spirits. Eighty percent of the local people were aware of cultural and religious aspects associated with the groves, whereas awareness about ecological and utilitarian values declined steeply to less than 20% of the population, necessitating the explanation of scientific conservation values of these critical ecosystems to the local people. The paper also discusses the significance of such studies in connection with the relevant UN Sustainable Development Goals and AICHI Biodiversity targets. In addition, it also discusses links with national biodiversity targets and how legal provisions under India's Biological Diversity Act (2002) can be used to benefit both the ecosystem and the cultural values of the people, and how such informal institutions can be strengthened under formal protection mechanisms.

Societal challenges regarding digital platforms—from privacy concerns to fake news or hate speech—are often framed around a deficit model of trust: they result in an erosion of user trust, and a need for its restoration is identified. Our contribution challenges this deficit model by examining the function of trust in digital platforms as sociotechnical systems. Platforms provide the infrastructure for a smooth transmission of data between various actors (e.g., users, developers, advertisers). This has inclusive as well as limiting effects: it provides broad accessibility by hiding complexity behind simple interfaces. Despite this detachment from the complex back end, risks and uncertainties are largely transferred to the users, who are expected to make informed decisions when they agree to platforms' terms and conditions. To be able to utilize platforms in everyday practices, users need to bridge uncertainties through trust. Trust fills the gap of lack of knowledge.
Our contribution sheds light on trust dynamics by combining trust theory with empirical insights. We distinguish trust from distrust and familiarity and specify at whom and at what trust is directed. Distrust of platforms has not led to significant transformations in the market, which remains dominated by the same players. The platforms' ecosystems heavily rely on trust in and by the users—for example, through the principle of informed consent. We identify an inflation of trust in the realm of digital platforms because trust is inherently risky due to its function of replacing knowledge. In contrast to the deficit model, we emphasize trust's problem component and frame our suggestions to meet the connected challenges accordingly.

Conversion of natural to anthropogenic environments affects biodiversity, and the understanding of these impacts may be improved by assessing how different functional groups respond to such land conversion. We studied land conversion impacts on ant functional groups, as ants are ecologically important and respond well to various environmental changes. We hypothesized that conversion of natural to anthropogenic environments modifies the composition of functional groups, fostering generalist and opportunistic groups over specialist ones, with more responses of this type in tropical than in temperate regions. We recovered 412 papers from ISI Web of Science, of which we selected 17 studies, published between 1993 and 2018, that addressed our study's question. We assessed whether each functional group responded positively or negatively to conversion of natural habitat into anthropogenic land uses and used Monte Carlo tests to assess significance. Ants were affected by natural habitat conversion into monoculture and polyculture and by the conversion of savannas and of tropical and subtropical forests. Land conversion affected six of the 13 functional groups assessed here. In the temperate zone, cryptic species, predators, subordinate Camponotini, cold-climate specialists and tropical-climate specialists were impaired, whereas hot-climate specialists were favored. In the tropics, land conversion negatively impacted fungus-growers and predators. In both climatic zones, several functional groups, mainly those with broad ecological niches, did not respond to land conversion. Our results corroborate that land conversion effects vary among ant functional groups and indicate that the ant fauna of temperate ecosystems may be more susceptible than that of tropical regions.

AbstractCo‐creation and open innovation have become an important source of competitive advantage. Over the past decades, huge amounts of information have become accessible to the external stakeholders of the organizations, changing the traditional value creation processes. However, co‐creation comes with its challenges, including the complex engagement of stakeholders, difficulties in opening up value chains and issues of trust and intellectual property. The arrival of blockchain and cryptographic asset‐driven decentralized technologies has brought to the world an entirely new spectrum of possibilities regarding social, financial and technological innovations. Now it is possible to achieve superior levels of transparency, security and fairness to the public, especially when compared with the rather limited business models that dominate Web 2.0 commercial products. While the first applications of blockchain technology were for digital currency transactions, that same technology is now being applied to the development of the blockchain‐based decentralized platforms. This calls for research to integrate other relevant fields such as organizational management, public policy, community engagement and marketing. This qualitative preliminary study aims to build an integrative and transdisciplinary framework of blockchain service ecosystems based on theoretical premises of Service Science through which blockchain‐based value co‐creation can be analysed. The systemic approach presented in this paper provides much‐needed guidance for developers of decentralized organizations on how to create sustainable platforms and to maintain them profitable in the long run. The focus of the proposed conceptual model is to initiate a scholarly curiosity in understanding possible solutions and potential impact of blockchain technology in the way we collaborate as a society.

AbstractOrganic contaminants are known to affect a suite of physiological processes across vertebrate clades. However, despite their ancient lineage and important roles in maintaining healthy ecosystems, elasmobranchs (sharks, skates, and rays) are understudied with regard to sublethal effects of contaminant exposure on metabolic processes. Perturbations resulting from contaminant exposure can divert energy away from maintaining physiological homeostasis, particularly during energetically challenging life stages, such as pregnancy and embryonic development. Using the round stingray (Urobatis halleri) as a model elasmobranch species, we captured adult males and pregnant females (matrotrophic histotrophy) and their embryos from two populations differing in their environmental exposure to organic contaminants (primarily polychlorinated biphenyls (PCBs)). Pregnant females from the PCB-exposed population experienced significant decreases from early- to late-pregnancy in tissue mass and quality not seen in reference females. PCB-exposed pregnant females also failed to maintain plasma urea concentrations as pregnancy progressed, which was accompanied by a loss in muscle protein content. Despite the energetic demands of late-term pregnancy, females had significantly greater liver lipid content than reproductively inactive adult males. PCB-exposed adult males also had high metabolic capacity (i.e., enzyme activity) for most substrate groupings of all sex-site groups, suggesting that males may be even more negatively impacted by contaminant exposure than pregnant females. Evidence that in utero exposure to PCBs via maternal offloading impairs embryo outcomes is accumulating. Embryos from the PCB-contaminated site had lower tissue quality measures and indications that sex-based differences were manifesting in utero as males had higher metabolic capacities than females. This study indicates that accumulated PCB contaminants are not physiologically inert in the stingray.

Invasive species have considerably increased in recent decades due to direct and indirect effects of ever‐increasing international trade rates and new climate conditions derived from global change. We need to better understand how the dynamics of early species invasions develop and how these result in impacts on the invaded ecosystems. Here we studied the distribution and severe defoliation processes of the box tree moth (Cydalima perspectalis W.), a tree defoliator insect native to Asia and invasive in Europe since 2007, through the combination of species distribution models based on climate and landscape composition information. The results showed that the combination of data from the native and the invaded areas was the most effective methodology for the appropriate invasive species modeling. The species was not influenced by overall landscape factors, but only by the presence of its host plant, dispersal capacity, and climate suitability. Such climate suitability was described by low precipitation seasonality and minimum annual temperatures around 0°C, defining a continentality effect throughout the territory. We emphasize the need of studying distribution and severe defoliation processes separately because we identified that climate suitability was slightly involved in limiting species spread processes but strongly constrained ecosystem impact in terms of defoliation before the species reaches equilibrium with the new environment. New studies on habitat recovery after disturbance, ecological consequences of such impact, and community dynamics in a context of climate change are required for a better understanding of this invasive species. ; This study was funded by the Government of Spain through the INMODES (CGL2017‐89999‐C2‐2‐R).

Climate change is anticipated to have long-term and widespread direct consequences for the European marine ecosystems and subsequently for the European fishery sector. Additionally, many socio-economic and political factors linked to climate change scenarios will impact the future development of fishing industries. Robust projection modeling of bioeconomic consequences of climate change on the European fishing sector must identify all these factors and their potential future interaction. In this study, four socio-political scenarios developed in the EU project CERES (Climate change and European aquatic RESources) were operationalized and used in model projections of marine wild capture fisheries. Four CERES scenarios (?World Markets,? ?National Enterprise,? ?Global Sustainability? and ?Local Stewardship") were based on the IPCC framework of Shared Socio-economic Pathways (SSPs). For each of these scenarios, a set of quantitative outputs was generated to allow projections of bio-economic impacts to mid-century (2050) on wild-capture fisheries operating in different European regions. Specifically, projections accounted for future changes in fisheries management targets, access regulations, international agreements, fish and fuel prices, technological developments and marine spatial planning. This study thoroughly describes the elements of these four fisheries scenarios and demonstrates an example of the ?regionalization? of these scenarios by summarizing how they were applied to the North Sea flatfish fishery. Bioeconomic projections highlight the importance of future developments in fuel and fish price development to the viability of that and other fisheries. Adapting these scenarios for use in other models and regions outside the 10 European fisheries examined in CERES would be highly beneficial by allowing direct comparison of the bioeconomic risks and opportunities posed by climate change.

International audience ; The forest decline in tropical areas is one of the largest global environmental threats as the growth of both global population and its needs have put an increasing pressure on these ecosystems. Efforts are ongoing to reduce tropical deforestation rates. Earth observations are increasingly used to monitor deforestation over the whole equatorial area. Change detection methods are mainly applied to satellite optical images which face limitations in humid tropical areas. For instance, due to frequent cloud cover in the tropics, there are often long delays in the detection of deforestation events. Recently, detection methods applied to Synthetic Aperture Radar (SAR) have been developed to address the limitations related to cloud cover. In this study, we present an application of a recently developed change detection method for monitoring forest cover loss from SAR time-series data in tropical zone. The method is based on the Cumulative Sum algorithm (CuSum) combined with a bootstrap analysis. The method was applied to time-series of Sentinel-1 ground range detected (GRD) dual polarization (VV, VH) images forming a dataset of 60 images to monitor forest cover loss in a legal forest concession of the Democratic Republic of Congo during the 2018-2020 period. A cross-threshold recombination was then conducted on the computed maps. Evaluated against reference forest cut maps, an overall accuracy up to 91% and a precision up to 75% in forest clear cut detection was obtained. Our results show that more than 60% of forest disturbances were detected before the PlanetScope-based estimated date of cut, which may suggest the capacity of our method to detect forest degradation.

© 2017, The Author(s). In a cross-disciplinary project (LEGATO) combining inter- and transdisciplinary methods, we quantify the dependency of rice-dominated socio-ecological systems on ecosystem functions (ESF) and the ecosystem services (ESS) the integrated system provides. In the collaboration of a large team including geo- and bioscientists, economists, political and cultural scientists, the mutual influences of the biological, climate and soil conditions of the agricultural area and its surrounding natural landscape have been analysed. One focus was on sociocultural and economic backgrounds, another on local as well as regional land use intensity and biodiversity, and the potential impacts of future climate and land use change. LEGATO analysed characteristic elements of three service strands defined by the Millennium Ecosystem Assessment (MA): (a) provisioning services: nutrient cycling and crop production; (b) regulating services: biocontrol and pollination; and (c) cultural services: cultural identity and aesthetics. However, in line with much of the current ESS literature, what the MA called supporting services is treated as ESF within LEGATO. As a core output, LEGATO developed generally applicable principles of ecological engineering (EE), suitable for application in the context of future climate and land use change. EE is an emerging discipline, concerned with the design, monitoring and construction of ecosystems and aims at developing strategies to optimise ecosystem services through exploiting natural regulation mechanisms instead of suppressing them. Along these lines LEGATO also aims to create the knowledge base for decision-making for sustainable land management and livelihoods, including the provision of the corresponding governance and management strategies, technologies and system solutions.

International audience ; The forest decline in tropical areas is one of the largest global environmental threats as the growth of both global population and its needs have put an increasing pressure on these ecosystems. Efforts are ongoing to reduce tropical deforestation rates. Earth observations are increasingly used to monitor deforestation over the whole equatorial area. Change detection methods are mainly applied to satellite optical images which face limitations in humid tropical areas. For instance, due to frequent cloud cover in the tropics, there are often long delays in the detection of deforestation events. Recently, detection methods applied to Synthetic Aperture Radar (SAR) have been developed to address the limitations related to cloud cover. In this study, we present an application of a recently developed change detection method for monitoring forest cover loss from SAR time-series data in tropical zone. The method is based on the Cumulative Sum algorithm (CuSum) combined with a bootstrap analysis. The method was applied to time-series of Sentinel-1 ground range detected (GRD) dual polarization (VV, VH) images forming a dataset of 60 images to monitor forest cover loss in a legal forest concession of the Democratic Republic of Congo during the 2018-2020 period. A cross-threshold recombination was then conducted on the computed maps. Evaluated against reference forest cut maps, an overall accuracy up to 91% and a precision up to 75% in forest clear cut detection was obtained. Our results show that more than 60% of forest disturbances were detected before the PlanetScope-based estimated date of cut, which may suggest the capacity of our method to detect forest degradation.