Search

Unprecedented and dramatic transformations are occurring in the Arctic in response to climate change, but academic, public, and political discourse has disproportionately focussed on the most visible and direct aspects of change, including sea ice melt, permafrost thaw, the fate of charismatic megafauna, and the expansion of fisheries. Such narratives disregard the importance of less visible and indirect processes and, in particular, miss the substantive contribution of the shelf seafloor in regulating nutrients and sequestering carbon. Here, we summarise the biogeochemical functioning of the Arctic shelf seafloor before considering how climate change and regional adjustments to human activities may alter its biogeochemical and ecological dynamics, including ecosystem function, carbon burial, or nutrient recycling. We highlight the importance of the Arctic benthic system in mitigating climatic and anthropogenic change and, with a focus on the Barents Sea, offer some observations and our perspectives on future management and policy. [ABSTRACT FROM AUTHOR]

Ectoparasitism has a damaging impact on the economy of goat production in India, but the factors influencing its distribution and dynamics are less explored. The present study was designed to investigate the influence of environmental factors like weather and air quality parameters on the occurrence of different types of ectoparasites in goats of two agro-climatic regions of India, viz. the Upper Gangetic Plain (UGP) and the Western Himalayas (WH). The prevalence survey for ectoparasitism among goats was conducted during the four distinct climatic seasons (winter, summer, monsoon, autumn) in both regions. The season-wise data of weather parameters (maximum and minimum temperature, relative humidity in morning and evening, sunrise and sunset time, mean daily temperature and relative humidity, daily variation in temperature and relative humidity, and day length) and air quality parameters (air quality index (AQI), particulate matter 2.5 μm (PM2.5), particulate matter 10 μm (PM10)) of both regions were analyzed in relation with the ectoparasitic prevalence pattern of corresponding regions. The results depict a noticeable correlation between the studied parameters and seasonal variation in the occurrence of each type of ectoparasites. This outcome on the interaction of studied parameters and ectoparasitism is intriguing and it opens a huge scope for future studies on the biometeorological aspects of host-parasite ecological interplay and evolutionary biology. The better understanding of climatological aspects of ectoparasite occurrences helps goat farmers in formulating appropriate timely intervention strategies for the economic control of ectoparasites, which in turn tackles ectoparasiticidal drug resistance and reduces threat of vector-borne diseases. [ABSTRACT FROM AUTHOR]

Direct observations of marine ecosystems are inherently limited in their temporal scope. Yet, ongoing global anthropogenic change urgently requires improved understanding of long-term baselines, greater insight into the relationship between climate and biodiversity, and knowledge of the evolutionary consequences of our actions. Sediment cores can provide this understanding by linking data on the responses of marine biota to reconstructions of past environmental and climatic change. Given continuous sedimentation and robust age control, studies of sediment cores have the potential to constrain the state and dynamics of past climates and ecosystems on timescales of centuries to millions of years. Here, we review the development and recent advances in “ocean drilling paleobiology”—a synthetic science with potential to illuminate the interplay and relative importance of ecological and evolutionary factors during times of global change. Climate, specifically temperature, appears to control Cenozoic marine ecosystems on million-year, millennial, centennial, and anthropogenic timescales. Although certainly not the only factor controlling biodiversity dynamics, the effect size of temperature is large for both pelagic and deep-sea ecosystems. [ABSTRACT FROM AUTHOR]

Long records of phenological observations constitute data for ecological, climate, and global change studies. Here we provide a unique dataset of plant phenological observations made in boreal Europe between 1750 and 1965 from locations situated across historical and modern Finland, mostly between 70° and 60° N and 30° and 20° E. This dataset was generated initially by the efforts of several generations of volunteers representing naturalists whose field observations and notes had initially made the continuous collection of the data possible. In addition, the data were collated by the Finnish Economic Society and the Finnish Society of Sciences and Letters and published irregularly in the form of several monographs and periodicals by contemporary academic enthusiasts. Each phenological observation contains 11 features including: site name, site latitude, site longitude, scientific species name, phenological stage, and (if any) its substage, year, date (month and day) and the day since the summer solstice, the original literature source, and outlier estimate. Species names given originally either in Latin, Finnish, German, and/or Swedish were transformed into scientific species names. Moreover, outdated taxonomic names were updated as appropriate. Phenological stages that had been given originally either in German, Finnish, and/or Swedish were transformed into English and standardized by excluding synonyms. Site names were adopted at the county level, with corresponding latitude and longitude generated herein. The digitized dataset represents 265,478 observations of 985 taxa (assigned to variety/subspecies/species/hybrid/genus) for their 16 different phenological stages made in 371 locations across the region. We provide this dataset to support comparative studies and modeling projects, seeking to improve the understanding of terrestrial ecosystem dynamics and its responses to a changing environment from a local to a global scale. Use of this dataset for academic or educational purposes is encouraged as long as the data source is correctly cited with attribution given to this presentation of the data. Users are free to use and analyze the data; additionally, we would like to hear from other researchers who use this dataset in teaching or for their own research. [ABSTRACT FROM AUTHOR]

The Gulf of Mexico is an ecologically and economically important marine ecosystem that is affected by a variety of natural and anthropogenic pressures. These complex and interacting pressures, together with the dynamic environment of the Gulf, present challenges for the effective management of its resources. The recent adoption of Bayesian networks to ecology allows for the discovery and quantification of complex interactions from data after making only a few assumptions about observations of the system. In this study, we apply Bayesian network models, with different levels of structural complexity and a varying number of hidden variables to account for uncertainty when modeling ecosystem dynamics. From these models, we predict focal ecosystem components within the Gulf of Mexico. The predictive ability of the models varied with their structure. The model that performed best was parameterized through data-driven learning techniques and accounted for multiple ecosystem components’ associations and their interactions with human and natural pressures over time. Then, we altered sea surface temperature in the best performing model to explore the response of different ecosystem components to increased temperature. The magnitude and even direction of predicted responses varied by ecosystem components due to heterogeneity in driving factors and their spatial overlap. Our findings suggest that due to varying components’ sensitivity to drivers, changes in temperature will potentially lead to trade-offs in terms of population productivity. We were able to discover meaningful interactions between ecosystem components and their environment and show how sensitive these relationships are to climate perturbations, which increases our understanding of the potential future response of the system to increasing temperature. Our findings demonstrate that accounting for additional sources of variation, by incorporating multiple interactions and pressures in the model layout, has the potential for gaining deeper insights into the structure and dynamics of ecosystems. [ABSTRACT FROM AUTHOR]

This is a review of over 400 published research papers on free-living, non-testate amoebae during the approximate last half century (1965-2017) particularly focusing on three topics: Biogeography, Ecology, and Physiology. These topics were identified because of the substantial attention given to them during the course of the last half century, and due to their potential importance in issues of local and global expanse, such as: aquatic and terrestrial stability of habitats, ecosystem processes, biogeochemistry and climate change, and the role of eukaryotic microbes generally in ecosystem services. Moreover, there are close epistemological and thematic ties among the three topics, making a synthesis of the published research more systematic and productive. The number of reviewed publications for each of the three individual topics is presented to illustrate the trends in publication frequencies during the historical period of analysis. Overall, the number of total publications reviewed varied somewhat between 1965 and early 2000 (generally less than 10 per year), but increased to well over 10 per year after 2000. The number of Biogeography and Ecology studies identified in the online citations increased substantially after the mid 1990s, while studies focusing on Physiology were relatively more abundant in the first decade (1965-1974) and less were identified in the 1985 to 2004 period. Citations to the literature are listed in tables for each of the three topics for convenience in retrieving references to specific aspects, and representative examples of the cited research in the tables are reviewed in the text under subheads dedicated to each of the three topics. Biogeographic studies largely focused on the geographic distribution and localized patterns of occurrence of amoebae, with more recent studies incorporating more attention to likely correlates with environmental and biotic factors in the distribution and community composition of amoebae. Ecological studies reviewed in the later decades tended to focus more on community dynamics, the effects of environmental variables on communities (including climate-related topics), a trend toward more physiological ecology studies, combined field-based and experimental studies, and incorporation of newer methodologies such as molecular genetics. In general, physiology studies in the first decades of the review tended to focus on topics of cell physiology such as basic biochemistry, enzyme assays, mechanisms of cell division and development, encystment, and motility. Later studies examined broader topics such as osmoregulation, nutrition, fine structure evidence of cellular changes during the life cycle (including encystment and excystment), and issues related to asexual and sexual reproduction, with increasing substantial evidence of evolutionary patterns and phylogenetics based on molecular evidence. A final section on Conclusions and Recommendations summarizes the findings and presents some potentially productive approaches to future research studies on Amoebozoa within the three designated topics of analysis. [ABSTRACT FROM AUTHOR]

Allelopathy is an important ecological phenomenon influencing ecosystem dynamics. Currently, it has gained attention due to the potential applications of allelochemicals in agriculture. Allelopathic interactions have been reported in ecological relationships between plants and microorganisms, and between species of each group. These studies have been relatively descriptive, however, without interconnected views of how these molecules can affect cell biology and how they are integrated into environmental interactions. The present review provides an overview of the history, physiology, and ecological effects of allelopathy, with special focus on its occurrence between macro- and microorganisms and its ecological roles in terrestrial and aquatic environments. We have attempted to examine the interconnections between terrestrial and aquatic systems in relation to the production, dynamics, and ecological effects of allelochemicals and to discuss the possible effects of climate changes on allelopathic interactions. [ABSTRACT FROM AUTHOR]

Lake Victoria has experienced human induced pressures such as overfishing, introduction of alien species, increased eutrophication and climate change impacts. However, there is limited understanding of the system dynamics, major processes, drivers and responses to the changes. To address this challenge, we developed the first end-to-end whole ecosystem model (Atlantis) for the lake. The model is spatially resolved into 12 unique dynamic areas based on depth, species composition, physical-chemical characteristics and fisheries management zones. A total of 38 functional groups constitute the biological model. Four fishing fleets with different targeting options are simulated. Reliability of the model is confirmed by the good fit of simulations output to observational data sets. Herein, we describe the evolution of the biophysical system, illustrating how it responded to the aforementioned induced perturbations since 1958. The constructed virtual Lake Victoria ecosystem model provides a platform for exploring the impact of management interventions before actual implementation. [ABSTRACT FROM AUTHOR]

Islands are traditionally considered sensitive to environment and climate change. The Caribbean Islands are a biodiversity hotspot, where conservation efforts should be a priority. However, the archaeological record suggests that the biotic characteristics of the islands, even within nature or forests reserves, are strongly shaped by thousands of years of intense human activity. This presents an issue for conservation efforts because defining what should be preserved and what should be reconstructed is not straightforward. Using Puerto Rico as case study, this article explores how socioecosystem dynamics influenced the biotic characteristics of the island at specific archaeological periods and to what extent these processes have affected the environmental resources on the island today. Climatic data, its implications on forest type and cover, and landscape characteristics as seen from sedimentary records, combined with archaeological data on human–environment interactions over time, from the mid-Holocene to the present are used to investigate these themes. This article brings forth more questions than answers, but it reflects the status of deep-time environmental research on the island, which is still in its early stages. I argue that, starting from the earliest occupations, human influence has altered the ecology of Puerto Rico so deeply that the natural resources we work toward preserving, conserving, or restoring today cannot be understood without considering the social contexts that shaped them. In this sense, if the Anthropocene is a proposal to rename the current geological period because of the overwhelming physical evidence of change that human activity has left behind, then the history of the Puerto Rico supports the proposal for the application of the term since at least 5 ka. Applying the concept would bring the relevance of human activity to the forefront, contributing to the reconsideration of the role of humans in the formation and preservation of modern ecological systems. [ABSTRACT FROM AUTHOR]

We investigated recent ecotone dynamics in the forest-grassland mosaics of southwestern Yukon. Our objectives were to determine ( i) if forests are encroaching into grasslands, ( ii) if rate and extent of encroachment varies by region or with topographic setting, and ( iii) if encroachment is related to climate change and variability. Dendroecological techniques were used to obtain dates of establishment for 1847 trees (trembling aspen ( Populus tremuloides Michx.) and white spruce ( Picea glauca (Moench) Voss)) sampled from 28 sites divided between two different regions and three topographic settings. Generalized linear modeling was used to identify relationships between climate and tree establishment. Results show that encroachment of forest, particularly aspen trees, into grasslands has been nearly ubiquitous on flat terrain and on south-facing slopes in both regions over the last 60-80 years. In contrast, spruce-dominated ecotones on north-facing slopes experienced little change. Aspen establishment was positively associated with spring temperatures and precipitation, although evidence suggests that other factors such as soil moisture interact with climate to mediate the timing and rate of tree encroachment. These results indicate that transformation of grasslands to aspen-dominated forest is an additional, but previously unexplored, element of the widespread ecosystem changes currently being experienced in northwestern North America. [ABSTRACT FROM AUTHOR]

Abstract: Degradation of grassland has become a worldwide environmental concern. This study examined temporal and spatial patterns of grassland potential productivity dynamics between 2000 and 2010 within community pastures (CPs) in Saskatchewan Canada. Data used in the study included Moderate-resolution Imaging Spectroradiometer (MODIS) 250m time-series NDVI, accumulated precipitation (A-PPT) from September to August and annual stocking intensity (SI). We conducted Mann–Kendall analysis on grassland growing season NDVI (GS-NDVI), A-PPT and SI to demonstrate spatial variation in their temporal trends at local and regional scales. We developed both global Ordinary Linear Square (OLS) and Geographically Weighted Regression (GWR) models to analyze the impacts of climate variation and human activities such as grazing practice on potential pasture productivity from both temporal and spatial contexts. Results show that grasslands in most CPs had increasing trends in GS-NDVI for the time period, and no significantly decreasing trend was found over all CPs at the regional or ecoregional scales. A-PPT itself accounted for over 96% of inter-annual variation in grassland NDVI. At the regional level, the temporal trends in A-PPT and stocking intensity were more significant factors in accounting for spatial variation of NDVI than were A-PPT and SI per se. Results show that the past adopted grazing intensities did not significantly influence grassland potential productivity at either temporal or spatial scales in the study area. [Copyright &y& Elsevier]

1: Given the predictions of increased drought probabilities under various climate change scenarios, there have been numerous experimental field studies simulating drought using transparent roofs in different ecosystems and regions. Such roofs may, however, have unknown side effects, called artifacts, on the measured variables potentially confounding the experimental results. A roofed control allows the quantification of potential artifacts, which is lacking in most experiments. 2: We conducted a drought experiment in experimental grasslands to study artifacts of transparent roofs and the resulting effects of artifacts on ecosystems relative to drought on three response variables (aboveground biomass, litter decomposition and plant metabolite profiles). We established three drought treatments, using (1) transparent roofs to exclude rainfall, (2) an unroofed control treatment receiving natural rainfall and (3) a roofed control, nested in the drought treatment but with rain water reapplied according to ambient conditions. 3: Roofs had a slight impact on air (+0.14°C during night) and soil temperatures (−0.45°C on warm days, +0.25°C on cold nights), while photosynthetically active radiation was decreased significantly (−16%). Aboveground plant community biomass was reduced in the drought treatment (−41%), but there was no significant difference between the roofed and unroofed control, i.e., there were no measurable roof artifact effects. 4: Compared to the unroofed control, litter decomposition was decreased significantly both in the drought treatment (−26%) and in the roofed control treatment (−18%), suggesting artifact effects of the transparent roofs. Moreover, aboveground metabolite profiles in the model plant species Medicago x varia were different from the unroofed control in both the drought and roofed control treatments, and roof artifact effects were of comparable magnitude as drought effects. 5: Our results stress the need for roofed control treatments when using transparent roofs for studying drought effects, because roofs can cause significant side effects. [ABSTRACT FROM AUTHOR]

Local and regional-scale knowledge of climate change is needed to model ecosystem responses, assess vulnerabilities and devise effective adaptation strategies. High-resolution gridded historical climate (GHC) products address this need, but come with multiple sources of uncertainty that are typically not well understood by data users. To better understand this uncertainty in a region with a complex climatology, we conducted a ground-truthing analysis of two 4 km GHC temperature products (PRISM and NRCC) for the US Northeast using 51 Cooperative Network (COOP) weather stations utilized by both GHC products. We estimated GHC prediction error for monthly temperature means and trends (1980–2009) across the US Northeast and evaluated any landscape effects (e.g., elevation, distance from coast) on those prediction errors. Results indicated that station-based prediction errors for the two GHC products were similar in magnitude, but on average, the NRCC product predicted cooler than observed temperature means and trends, while PRISM was cooler for means and warmer for trends. We found no evidence for systematic sources of uncertainty across the US Northeast, although errors were largest at high elevations. Errors in the coarse-scale (4 km) digital elevation models used by each product were correlated with temperature prediction errors, more so for NRCC than PRISM. In summary, uncertainty in spatial climate data has many sources and we recommend that data users develop an understanding of uncertainty at the appropriate scales for their purposes. To this end, we demonstrate a simple method for utilizing weather stations to assess local GHC uncertainty and inform decisions among alternative GHC products. [ABSTRACT FROM AUTHOR]

Theory posits that community dynamics organize at distinct hierarchical scales of space and time, and that the spatial and temporal patterns at each scale are commensurate. Here we use time series modeling to investigate fluctuation frequencies of species groups within invertebrate metacommunities in 26 boreal lakes over a 20-year period, and variance partitioning analysis to study whether species groups with different fluctuation patterns show spatial signals that are commensurate with the scale-specific fluctuation patterns identified. We identified two groups of invertebrates representing hierarchically organized temporal dynamics: one species group showed temporal variability at decadal scales (slow patterns of change), whilst another group showed fluctuations at 3 to 5-year intervals (faster change). This pattern was consistently found across all lakes studied. A spatial signal was evident in the slow but not faster-changing species groups. As expected, the spatial signal for the slow-changing group coincided with broad-scale spatial patterns that could be explained with historical biogeography (ecoregion delineation, and dispersal limitation assessed through a dispersal trait analysis). In addition to spatial factors, the slow-changing groups correlated with environmental variables, supporting the conjecture that boreal lakes are undergoing environmental change. Taken together our results suggest that regionally distinct sets of taxa, separated by biogeographical boundaries, responded similarly to broad-scale environmental change. Not only does our approach allow testing theory about hierarchically structured space-time patterns; more generally, it allows assessing the relative role of the ability of communities to track environmental change and dispersal constraints limiting community structure and biodiversity at macroecological scales. [ABSTRACT FROM AUTHOR]

Abstract: It is widely recognised that the response of a population to environmental change will be determined by the eco-evolutionary dynamics of dispersal. Here, modelling the evolution of dispersal distance within a species structured across an environmental gradient yields some important general insights. First, it demonstrates that ‘elastic’ ranges are more likely features of range-shifting dynamics than has been recently reported; when dispersal distance, rather than simply emigration rate, is modelled elastic ranges occur regardless of the nature of the environmental gradient. Second, we start to identify critical survival thresholds beyond which even the evolution of greater dispersal distance is unlikely to rescue a population. The position of such thresholds depends on a combination of genetic, demographic and environmental parameters. We find simulated species rarely survive if the location of the range front of a range-shift falls behind the optimal environmental conditions of the species. Should similar thresholds exist for real species aggressive conservation actions such as assisted colonisation are likely to be required to reduce the risk of extinction. We believe simple models, such as the one presented in this study, will be essential for providing a theoretical underpinning for more tactical eco-evolutionary models and informing conservation strategies to be employed under rapid climate change. [Copyright &y& Elsevier]

Background: Little is known about the combined impacts of global environmental changes and ecological disturbances on ecosystem functioning, even though such combined impacts might play critical roles in shaping ecosystem processes that can in turn feed back to climate change, such as soil emissions of greenhouse gases. Methodology/Principal Findings: We took advantage of an accidental, low-severity wildfire that burned part of a long-term global change experiment to investigate the interactive effects of a fire disturbance and increases in CO2 concentration, precipitation and nitrogen supply on soil nitrous oxide (N2O) emissions in a grassland ecosystem. We examined the responses of soil N2O emissions, as well as the responses of the two main microbial processes contributing to soil N2O production - nitrification and denitrification - and of their main drivers. We show that the fire disturbance greatly increased soil N2O emissions over a three-year period, and that elevated CO2 and enhanced nitrogen supply amplified fire effects on soil N2O emissions: emissions increased by a factor of two with fire alone and by a factor of six under the combined influence of fire, elevated CO2 and nitrogen. We also provide evidence that this response was caused by increased microbial denitrification, resulting from increased soil moisture and soil carbon and nitrogen availability in the burned and fertilized plots. Conclusions/Significance: Our results indicate that the combined effects of fire and global environmental changes can exceed their effects in isolation, thereby creating unexpected feedbacks to soil greenhouse gas emissions. These findings highlight the need to further explore the impacts of ecological disturbances on ecosystem functioning in the context of global change if we wish to be able to model future soil greenhouse gas emissions with greater confidence. [ABSTRACT FROM AUTHOR]