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opencc-zeroMar 2021View details →

More widespread alien tree species do not have larger impacts on regeneration of native tree species in a tropical forest reserve

There is insufficient information regarding the factors affecting the environmental impacts of alien species. In particular, little is known about whether there is any relationship between the invasiveness (establishment and spread) of an introduced species and its per-capita impact. We experimentally assessed the relationship between the extent of spread of up to 29 alien plant species and their impact on recruitment of native tree species in Amani Botanical Garden, Tanzania. We also studied the effects of allelochemicals of selected alien on native plant species to assess potential mechanisms of impact. We found no relationship between the extent of spread of an alien tree species and their impact on seed germination, seedling survival and seedling communities of native trees in their understory, and no indication that allelochemicals consistently explain their effects on recruitment of the studied species. These results suggest that extent of spread cannot be used as a proxy for impact. Hence, managers should continue assessing both the spread and the impact of alien species when prioritising alien species for management.

Data from: High detectability with low impact: Optimising large PIT tracking systems for cave-dwelling bats

Passive integrated transponder (PIT) tag technology permits the 'resighting' of animals tagged for ecological research without the need for physical re-trapping. While this is effective if animals pass within centimetres of tag readers, short-distance detection capabilities have prevented the use of this technology with many species. To address this problem, we optimised a large (15 m-long) flexible antenna system to provide a c. 8 m2 vertical detection plane for detecting animals in flight. We installed antennas at two roosting caves, including the primary maternity cave, of the critically endangered southern bent-winged bat (Miniopterus orianae bassanii) in south-eastern Australia. Testing of these systems indicated PIT-tags could be detected up to 105 cm either side of the antenna plane. Over the course of a three-year study, we subcutaneously PIT-tagged 2966 bats and logged over 1.4 million unique detections, with 97% of tagged bats detected at least once. The probability of encountering a tagged bat decreased with increasing environmental 'noise' (unwanted signal) perceived by the system. During the study we mitigated initial high noise levels by earthing both systems, which contributed to an increase in daily detection probability (based on the proportion of individuals known to be alive that were detected each day) from <0.2 (noise level ≥30%) to 0.7-0.8 (noise level 5-15%). Conditional on a low (5%) noise level, model-based estimates of daily encounter probability were highest (>0.8) during peak breeding season when both female and male southern bent-winged bats congregate at the maternity cave. In this paper we detail the methods employed and make methodological recommendations for future wildlife research using large antennas, including earthing systems as standard protocol and quantifying noise metrics as a covariate influencing the probability of detection in subsequent analyses. Our results demonstrate that large PIT antennas can be used successfully to detect small volant species, extending the scope of PIT technology and enabling a much broader range of wildlife species to be studied using this approach.

Data from: Differential impacts of nitrogen addition on rhizosphere and bulk-soil carbon sequestration in an alpine shrubland

1. Due to complex root-soil interactions, the responses of carbon (C) dynamics in the rhizosphere to elevated nitrogen (N) deposition may be different from those in bulk soil. However, the potentially different response of C dynamics in the rhizosphere and bulk soils and their contributions to soil C sequestration under N deposition is still not elucidated. 2. We conducted an N addition experiment in an alpine shrubland dominated by Sibiraea angustata located on the eastern Qinghai-Tibet Plateau (QTP). We measured the soil organic C (SOC) contents and density fractions in the rhizosphere and bulk soils in the top 15 cm of mineral soil and then employed a numerical model based on the rhizosphere extent to evaluate how the rhizosphere modulates soil C sequestration under N addition. We also measured the microbial gene abundance and C-acquisition enzyme activities to assess microbial community responses to N addition. 3. The results showed that nitrogen addition had opposite effects on the rhizosphere and bulk-soil C stocks. Specifically, N addition decreased the rhizosphere SOC content through increasing bacterial abundance, β-glucosidase activity, and thus accelerating the loss of free light fraction C (FLF-C). However, N addition increased the bulk-soil C content, which was corresponding with the reduced oxidase activities and the accelerated accumulation of heavy fraction C (HF-C) under N addition. Numerical model analysis showed that the decrease induced by N addition in rhizosphere SOC stock ranged from 0.11 to 3.01 kg C m-2 as root exudation diffusion distance extended from 0.5 mm to 2 mm, while the corresponding increase in the bulk-soil C stock ranged from 1.91 to 4.08 kg C m-2. By synthesizing the dynamics of the SOC stocks in these two soil compartments under N addition, the SOC stock at the ecosystem level exhibited an increase in range of 0.73-2.44 kg C m-2. 4. Synthesis Our results suggest that alpine shrublands on the eastern QTP have great potential for soil C sequestration under N deposition, and the magnitude of the sequestration would depend closely on the responses of rhizosphere microbial C processes and the rhizosphere extent. Our results highlight the importance of integrating rhizosphere processes into land surface models to accurately predict ecosystem functions in the background of elevated N deposition.

opencc-zeroDec 2018View details →

Data from: Colonial history impacts urban tree species distribution in a tropical city

Urban forests associated with green infrastructure for sustainable outcomes are particularly critical in the Global South, where some of the world's fastest-growing cities are located. However, compared to temperate cities, the drivers of urban tree species distribution in tropical cities remain understudied. In this study, we quantify the spatial distribution and abundance of urban forests in the tropical city of Georgetown, Guyana. British colonialism has shaped this city, including forced movement of peoples under slavery from Africa and indentured servants from the Indian Subcontinent. We studied how this multicultural context has influenced tree species distributions in the capital city of the only Anglophone country in South America. We quantified the abundance of tree species using a stratified sampling design to distribute transects across fifteen neighborhoods that vary in distance to the colonial center of the city and ethnic composition. We recorded a total of 57 unique species, the majority of which (73%) were cultivated for their edible fruits. We identify tree species that likely represent Guyana's unique multicultural heritage by comparing our species list to flora in nine cities in neighboring countries (Venezuela and Brazil) with different colonial histories. This international comparison identified a set of tree species that occurred only in Guyana. Relationships between ethnic composition and colonial history and tree species distribution were weak at the neighborhood scale, where proportion of East Indian residents had little explanatory power and distance to colonial center was correlated with abundance of only some species groups. This apparent discrepancy between neighborhood and national scales may relate to the establishment of Guyanese food as a unifying national identifier across ethnicities. The prominence of edible fruit trees in our study suggests a set of species that could be incorporated into urban planning to strengthen biocultural linkages, foster cultural integration, and promote food security.

opencc-zeroDec 2019View details →

Characterizing uncertainty in climate impact projections: a case study with seven marine species on the North American continental shelf

Projections of climate change impacts on living resources are being conducted frequently, and the goal is often to inform policy. Species projections will be more useful if uncertainty is effectively quantified. However, few studies have comprehensively characterized the projection uncertainty arising from greenhouse gas scenarios, Earth system models, and both structural and parameter uncertainty in species distribution modeling. Here we conducted 8964 unique 21st century projections for shifts in suitable habitat for seven economically important marine species including American lobster, Pacific halibut, Pacific ocean perch, and summer flounder. For all species, both the Earth system model used to simulate future temperatures and the niche modeling approach used to represent species distributions were important sources of uncertainty, while variation associated with parameter values in niche models was minor. Greenhouse gas emissions scenario contributed to uncertainty for projections at the century scale. The characteristics of projection uncertainty differed among species and also varied spatially, which underscores the need for improved multi-model approaches with a suite of Earth system models and niche models forming the basis for uncertainty around projected impacts. Ensemble projections show the potential for major shifts in future distributions. Therefore, rigorous future projections are important for informing climate adaptation efforts.

zenodo32/100

Data related to Sasse et al. (2020) "Regional impacts of electricity system transition in Central Europe until 2035"

This is the accompanying dataset for the publication "Regional impacts of electricity system transition in Central Europe until 2035".  The dataset contains the following input data files: <ul> <li>Capacity_Factor_EXPANSE.csv: annual capacity factors per NUTS-3 region and electricity generation technology, used by the EXPANSE model, in MWh/MWh</li> <li>Demand_EXPANSE.csv: annual electricity demand per NUTS-3 region, used by the EXPANSE model, in MWh and in TWh</li> <li>LCOE_EXPANSE.csv: levelized electricity generation costs per NUTS-3 region and electricity generation technology, used by the EXPANSE model, in EUR/MWh</li> <li>Emax_EXPANSE.csv: maximum annual electricity generation potential per NUTS-3 region and electricity generation technology, used by the EXPANSE model, in MWh</li> <li>Emin_EXPANSE.csv: minimum annual electricity generation potential per NUTS-3 region and electricity generation technology, used by the EXPANSE model, in MWh</li> <li>Costs_PyPSA.csv: Cost assumptions, used by the PyPSA model, units defined in units column</li> </ul> The dataset contains the result data files: <ul> <li>Aggregated_Impacts.csv: Aggregated impacts for all MGA scenarios and distinct scenarios, units defined in each column</li> <li>Regional_Impacts.csv: Regional impacts for all distinct scenarios, units defined in each column</li> </ul>

opencc-by-4.0Jul 2020View details →

Data from: Projected impacts of warming seas on commercially fished species at a biogeographic boundary of the European continental shelf

1. Projecting the future effects of climate change on marine fished populations can help prepare the fishing industry and management systems for resulting ecological, social and economic changes. Generating projections using multiple climate scenarios can provide valuable insights for fisheries stakeholders regarding uncertainty arising from future climate data. 2. Using a range of climate projections based on the Intergovernmental Panel on Climate Change A1B, RCP4.5 and RCP8.5 climate scenarios, we modelled abundance of eight commercially important bottom dwelling fish species across the Celtic Sea, English Channel and southern North Sea through the 21st century. This region spans a faunal boundary between cooler northern waters and warmer southern waters, where mean sea surface temperatures are projected to rise by 2 to 4ºC by 2098. 3. For each species, Generalised Additive Models were trained on spatially explicit abundance data from six surveys between 2001 and 2010. Annual and seasonal temperatures were key drivers of species abundance patterns. Models were used to project species abundance for each decade through to 2090. 4. Projections suggest important future changes in the availability and catchability of fish species, with projected increases in abundance of red mullet (Mullus surmuletus L.), Dover sole (Solea solea L.), John dory (Zeus faber L.) and lemon sole (Microstomus kitt L.) and decreases in abundance of Atlantic cod (Gadus morhua L.), anglerfish (Lophius piscatorius L.) and megrim (Lepidorhombus whiffiagonis L.). European plaice (Pleuronectes platessa L.) appeared less affected by projected temperature changes. Most projected abundance responses were comparable among climate projections, but uncertainty in the rate and magnitude of changes often increased substantially beyond 2040. 5. Synthesis and applications. These results indicate potential risks as well as some opportunities for demersal fisheries under climate change. These changes will challenge current management systems, with implications for decisions on target fishing mortality rates, fishing effort and allowable catches. Increasingly flexible and adaptive approaches that reduce climate impacts on species while also supporting industry adaptation are required.

Data from: Invasive dominance and resident diversity: unpacking the impact of plant invasion on biodiversity and ecosystem function

Plant invasions have consistently been shown to cause significant reductions in the diversity of recipient plant communities; an effect that can cascade through ecosystems to impact the stocks and flows of nutrients and energy as well as the diversity of higher trophic levels. However, the manner in which invasive plants alter ecosystem functioning and trophic interactions is highly variable can occur through the direct effects of the invader's abundance and its indirect effects via changes in community diversity. Understanding the nature of these interactions between plant invasion, community diversity and ecosystem functioning can provide insight for ecosystem managers. We evaluated whether plant invasion alters the relationship between biodiversity and ecosystem function (BEF) by comparing BEF models that either include or subtract the diversity and function values associated with the invasive vine, Vincetoxicum rossicum. To do this, we 1) characterize V. rossicum within the functional trait space of the regional species pool; 2) assess how different components of plant biodiversity vary along a V. rossicum invasion gradient; and 3) examine how V. rossicum invasion affects BEF relationships and trophic interactions, both at the plot-scale and incrementally along a site-level invasion gradient. In general, we found that V. rossicum invasion was associated with significant declines in plant community diversity across a suite of biodiversity measures; a consequence of V. rossicum's functional trait structure (height and specific leaf area). We also found that V. rossicum invasion resulted in significantly greater productivity (i.e. dominance effects in the inclusion model), but also that the diversity of the remaining resident community was positively associated with productivity (i.e. niche complementarity in the subtraction model). Further, we observed that while the relationship between flower cover and pollinator diversity was positive for both the inclusion and subtraction models, this relationship was stronger in the absence of V. rossicum. Our findings suggest that while plant invasion can result in enhanced productivity via dominance effects, this comes at the cost of significant declines in diversity. However, it is also the case that remaining resident diversity can exhibit positive effects on multiple functions and support for higher trophic levels.

The legacy of stress: coral bleaching impacts reproduction years later

1. The extent to which populations persist under environmental stress depends on the reproductive output of individuals that survive the stress. In coral systems, corals bleach in response to stress from elevated water temperature. However, little is known of the extent to which thermal stress impairs the reproductive capacity of the survivors over the following years, limiting the capacity to predict how populations will persist in the Anthropocene. 2. Using histology to quantify the abundance and size of oocytes and spermaries per polyp, we tested how bleaching impairs the reproductive response of the coral Pocillopora meandrina over two reproductive seasons following the 2015 mass bleaching event in the Hawaiian Islands. 3. We found that smaller colonies not only had a greater probability of bleaching but also suffered greater reproductive impacts over a longer time. In contrast, larger colonies generated comparable reproductive output regardless of bleaching severity, although bleached colonies generated smaller oocytes the year after bleaching. 4. These results show that reproductive impacts of bleaching are more complex and size-specific than commonly assumed. Therefore, estimates of bleaching mortality may underestimate the true impact of thermal stress on populations, especially as populations lose larger individuals from repeated and co-occurring stressors.

The impact of local population genetic background on the spread of the selfish element Medea-1 in red flour beetles

Selfish genetic elements have been found in the genomes of many species, yet our understanding of their evolutionary dynamics is only partially understood. A number of distinct selfish Medea elements are naturally present in many populations of the red flour beetle (Tribolium castaneum). Although these Medea elements are predicted by models to increase in frequency within populations because any offspring of a Medea-bearing mother that do not inherit at least one Medea allele will die, experiments demonstrating an increase in a naturally occuring Medea element are lacking. Our survey of the specific Medea element, M1, in the United States showed that it had a patchy geographic distribution. From the survey it could not be determined if this distribution was caused by a slow process of M1 colonization of discrete populations or if some populations lacked M1 because they had genetic factors conferring resistance to the Medea mechanism. We show that populations with naturally low to intermediate M1 frequencies likely represent transient states during the process of Medea spread. Furthermore, we find no evidence that genetic factors are excluding M1 from US populations where the element is not presently found. We also show how a known suppressor of Medea can impair the increase of M1 in populations and discuss the implications of our findings for pest-management applications of Medea elements.

Uncovering transport, deposition and impact of radionuclides released after the early spring 2020 wildfires in the Chernobyl Exclusion Zone

In the beginning of April 2020, large fires that started in the Chernobyl Exclusion Zone (CEZ) established after the Chernobyl accident in 1986 caused media and public concerns about the health impact from the resuspended radioactivity. In this paper, the emissions of previously deposited radionuclides from these fires are assessed and their dispersion and impact on the population is examined relying on the most recent data on radioactive contamination and emission factors combined with satellite observations. About 341 GBq of 137Cs, 51 GBq of 90Sr, 2 GBq of 238Pu, 33 MBq of 239Pu, 66 MBq of 240Pu and 504 MBq of 241Am were released in 1st–22nd April 2020 or about 1,000,000,000 times lower than the original accident in 1986 and mostly distributed in Central and East Europe. The large size of biomass burning particles carrying radionuclides prevents long-range transport as confirmed by low concentrations reported in Europe. The highest cumulative effective doses (>15 μSv) were calculated for firefighters and the population living in the CEZ, while doses were much lower in Kiev (2–5 μSv) and negligible in Europe. All doses are radiologically insignificant and no health impact on the European population is expected from the April 2020 fires.

opencc-zeroApr 2021View details →

Human impact overrides bioclimatic drivers of red fox home range size globally

Aim Identifying the variables that influence animal home range size is important for understanding the biological requirements of individuals and their social interactions. Given their often broad distributions, carnivores are model organisms for studying range-wide determinants of home range size. Here we test predictions about environmental determinants of home range size for one of the world's most widely distributed carnivores, the red fox (Vulpes vulpes). Location Global Methods We compiled a database of 70 mean home range estimates from 62 studies and four continents, which we analysed according to site-based temperature, precipitation, environmental productivity and human influence variables. Results We found a very strong negative effect of the Human Footprint Index (HFI), with fox home range size decreasing as the level of human impact increased. When analysing the constituent components of the HFI separately, we found that human population density was the only well supported variable (cf. built environments, croplands, pasture lands, nightlights, railways, roads and navigable waterways). Predicted home range size at the highest human population densities (0.75 km2) was 93% lower than at the lowest population densities (10.83 km2). We also found that home range size increased as mean annual temperature and temperature seasonality increased. The analyses did not support our prediction that home ranges would be smaller in areas of higher environmental productivity or precipitation. Main conclusions Smaller home range sizes observed in highly disturbed areas can be attributed to increased food availability from anthropogenic sources. The lack of an effect of environmental productivity contrasts with previous studies that have shown a negative relationship with carnivore home range size. It may be that anthropogenic food sources have negated the impacts that low productivity environments have on fox home ranges. Our results emphasise the strong potential for human activities to transform animal space use across the globe.

A meta-analysis of biological impacts of artificial light at night

This is a database of published studies, that measuered how the exposure to artificial light at night impacts the physiology, daily activity patterns and life-history traits. The data were collected using a systematic review with searches in Web of Science and Scopus. We also provide the R-code that was used to analyse the dataset with meta-analytic models in MCMCglmm.

The impact of learning opportunities on the development of learning and decision making: an experiment with passerine birds

Learning abilities have been shown to be influenced by the developmental context, namely through experiments that imposed severe nutritional and/or environmental constraints (i.e. lack of enrichment). In contrast, we know little on the impact of opportunities for learning on the development of cognition in animals, despite that such opportunities are known to influence human cognitive development. We exposed young zebra finches (Taenopygia guttata) (n=26) to one of three experimental conditions, i.e. an environment where (i) the presence of food was predicted by one colour cue (associative learning), (ii) a combination of two-colour cues (conditional learning), or (iii) colour cues were non-informative (control). After conducting two different discrimination tasks, our results show that experience with predictive cues can cause increased choice accuracy and decision-making speed. Our first learning task showed that individuals in the associative treatment outperformed the control treatment, while task 2 showed that individuals in the conditional treatment shad shorter latencies when making choices compared to the control treatment. We found no support for a speed-accuracy trade-off. This dataset provides a rare longitudinal and experimental examination of the effect of predictive vs non-predictive cues during development on the cognition of adult animals.

opencc-zeroMay 2020View details →

Data from: Social facilitation can impact the responses of free-ranging dogs (Canis lupus familiaris) towards physical cognitive tasks

Dogs are known to persist less in problem-solving tasks independently. While most of the studies so far have reported results based on experiments in pet dogs, conclusive evidence from free-ranging subpopulations is lacking. Free-ranging dogs are primarily scavengers and require problem-solving abilities to survive. We provided dogs with a familiar or an unfamiliar task in the presence of conspecifics. Both the tasks provided a single food-reward upon solving. We coded success, latency, and the duration of active engagement of the dogs in this study. We compared them with an earlier published dataset where individual dogs were tested in identical experimental set-ups. Our findings show that dogs have higher success rates in both the familiar and unfamiliar tasks when tested in the presence of conspecifics than when alone, suggesting a role of social facilitation. Furthermore, the presence of conspecifics facilitated dogs to approach faster and engage longer in the unfamiliar task than when tested alone. We provide the first evidence that social facilitation may play a crucial role in free-ranging dogs, especially in the context of problem-solving.

Impacts of rodent eradication on seed predation and plant community biomass on a tropical atoll

Invasive rodent eradications are frequently undertaken to curb island biodiversity loss. However, the breadth of rodents' ecological impact, even after eradication, is not always fully recognized. For example, the most widespread invasive rodent, the black rat (Rattus rattus), while omnivorous, eats predominantly seeds and fruit. Yet, the effects of seed predation release after eradication on plant communities and ecological functions are not well understood, posing a gap for island restoration. We examined the role of seed predation release following black rat eradication in changes to tree composition and above-ground biomass across an islet network (Palmyra Atoll) in the Central Pacific. We conducted repeated surveys of seed, juvenile, and adult tree biomass and survival in permanent vegetation plots before and after the eradication of rats. We observed a 95% reduction in seed predation for an introduced, previously cultivated tree population (Cocos nucifera). Juvenile tree biomass of all species increased 14-fold, with C. nucifera increasing the most, suggesting that eradication increased this tree's competitive advantage. Indeed, based on stage-structured demographic models, rat eradication led to a 10% increase in C. nucifera population growth rate. The effect of invasive rodent seed predation varies considerably among the plant species in a community and can shift competitive dynamics, sometimes in favor of invasive plants. These bottom-up effects should be considered in evaluating the costs and benefits of eradication. Documenting the variation in invasive rodent diet items, along with long-term surveys, can help prioritize island eradications where restoration is most likely to be successful.

opencc-by-4.0Aug 2020View details →

zenodo32/100

Multi-year impact of maternal provisioning on a juvenile elasmobranch: pitfalls of tissue type and tracer number for stable isotope analysis

Stable isotope data and R script for all the analysis referred to in the manuscript.

zenodo32/100

Data for Mooring Impacts on Zostera marina Meadows and Associated Epifauna in Nantucket Harbor, Massachusetts, USA

Submitted in fulfillment of a 2015 Nantucket Biodiversity Initiative grant. Excerpt from thesis abstract: "To explore the connections between mooring scarring, the surrounding seagrass meadow condition and epifaunal community, in the second part of this thesis I measured 30 mooring scars to determine average scar size. To explore any potential "halo" effect around mooring scars for seagrass or epifauna and to seek any difference in epifaunal community between mooring and reference sites I also sampled paired sites at eight locations in Nantucket Harbor, Massachusetts three times each in the summer of 2015. Each location consisted of a meadow site actively experiencing mooring scarring and a reference site without moorings. My conservative sampling methods of the 30 sampled mooring scars found scars to average 21.1m2. Across my paired sites, seagrass was found to have lower cover and lower canopy height in mooring versus reference sites. Seagrass cover and canopy height were lower in the first few meters (typically 2-3m) surrounding each scar in comparison to paired reference quadrats indicating a "halo" effect of each scar. I did not detect a difference in epifaunal community composition or density per blade between mooring and reference sites; however, the relatively constant per blade concentration of epifauna combined with the differences in seagrass biomass between the mooring versus reference sites indicate an overall increase in the total amount of epifauna in areas with less disturbance. Epifaunal community composition was different and between locations and sampling dates indicating these factors are more important than proximity to mooring scarring in determining epifaunal abundance and richness."

opencc-by-4.0Sep 2020View details →

The way bioclimatic variables are calculated has impact on potential distribution models

1. Bioclimatic variables (BCVs) are routinely used in potential distribution models, typically without considering their calculation options in detail. We aimed at studying the impact of a decision, yet unexamined, on the calculation of BCVs, namely whether the identity of specific months/quarters in the calculation of BCVs should be updated for the future periods (temporal context). Effects on the performance of potential distribution models and on their projections were investigated. Additionally, we also aimed at comparing the impact of month/quarter shifts to that of climate model selection and covariate selection. 2. Potential natural vegetation models encompassing eight habitat types and the whole territory of Hungary were created using boosted regression trees. We tested multiple initial covariate sets to compare the impact of the temporal context to that of covariate selection. The resulting models were applied to the reference and one future time period (with data from two regional climate models). The effect of the BCV calculation approach was tested by linear mixed-effects models and model goodness-of-fit measures in a comprehensive framework of 192 predictions. Area Under the ROC Curve (AUC) and True Positive Rate (TPR) curves were used to evaluate the models. 3. Our results show that (1) temporal context of BCVs in interaction with covariate selection had a strong effect on model structure as well as on projections; (2) no evidence supporting the superiority of the widely applied calculation approach of BCVs was found. However, we found notable differences under the two approaches and examples of projection artefacts when applying the widespread way of calculation. 4. We conclude that (1) more attention and more transparent communication is needed when BCVs are used as covariates in distribution models; (2) not only ecophysiology but also the way covariates are calculated should be considered when preselecting covariates for potential distribution models.