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671 results for “mediating effect”
The effects of LED-mediated photobiomodulation vs no photobiomodulation on extraction space closure in adolescents and young adult patients: A split-mouth, randomized controlled trial.
<p>The aim of this split-mouth trial was is to examine the effects of light emitting diode (LED)-mediated photobiomodulation (PBM) compared to no photobiomodulation on maxillary canine distalization.</p> <p>The dataset is openly provided upon acceptance for publication.</p>
Species interactions across trophic levels mediate rainfall effects on dryland vegetation dynamics
<p>Arid ecosystems are strongly limited by water availability, and precipitation plays a major role in the dynamics of all species in arid regions, as well as the ecosystem processes that occur there. However, understanding how biotic interactions mediate long-term responses of dryland ecosystems to rainfall remains very fragmented. We report on a unique large-scale field experiment spanning 25 years and three trophic levels (plants, small mammal herbivores, predators) in a dryland ecosystem in the northern Chilean Mediterranean Region where we assessed how biotic interactions influence the long-term plant community responses to precipitation. As the most persistent ecological changes in dryland systems may result from changes in the structure, cover, and composition of the perennial vegetation, we emphasized the interplay between bottom-up and top-down controls of perennial plants in our analyses. Rainfall was the primary factor affecting the dynamics of, and interactions among, plants and small mammals. Ephemeral plant cover dynamics closely tracked short-term annual rainfall, but seemed unaffected by top-down controls (herbivory). In contrast, the response of the perennial plant cover to precipitation was mediated by: (i) a complex interplay between subtle top-down (herbivory) controls that become more apparent in the long-term, (ii) competition with ephemeral plants during wet years, and (iii) an indirect effect of predators on subdominant shrubs and perennial herbs. This long-term field experiment highlights how climate-induced responses of arid perennial vegetation are influenced by interactions across trophic levels and temporal scales. In the face of global change, understanding how multi-trophic controls mediate dryland vegetation responses to climate is essential to properly managing the conservation of biodiversity in arid systems.</p>
Pollinator-mediated facilitation alleviates pollen limitation through effects on the quality of plant reproduction
<p>Facilitation and competition among plants sharing pollinators have contrasting consequences for each species' fitness. However, it is unclear whether pollinator-mediated indirect interactions between plants affect plant fitness in a multispecies context. Here, we investigated how pollinator sharing affects pollen limitation (contribution of pollination to fitness) in a tropical hummingbird-pollinated community marked by facilitation. We employed indices describing how much a plant species is important to shared pollinators (acting degree) and have its shared pollinators influenced by other plants (target degree) within the plant-hummingbird network. Since facilitation often increases pollination quantity but not necessarily quality, we expected both indices to be associated with reductions in pollen limitation estimates that depend on pollination quantity (fruit set and seed number) rather than estimates more strictly related to quality (seed weight and germination). Instead, we found that both indices were associated with reductions in pollen limitation only for seed weight and germination. Thus, facilitation acted on qualitative estimates of pollen limitation. Our results suggest that facilitation may enhance plant fitness even if quantitative components of plant fecundity are already saturated. Overall, we showed that pollinator-mediated indirect effects in a multispecies context are important drivers of plant fitness with consequences for coexistence in diverse communities.</p>
Seminal fluid-mediated fitness effects in the simultaneously hermaphroditic flatworm Macrostomum lignano
<p>As a class, seminal fluid proteins are expected to exert strong effects on mating partners due to the selection pressures of sperm competition and sexual conflict. But because of the complexity of this secretion, linking specific proteins to downstream effects on own fitness – via manipulating the reproductive behavior, physiology and ultimately the sperm utilization of mating partners – is not straightforward. Here we adopted a systematic gene knockdown approach to screen for seminal fluid-mediated fitness effects in the simultaneously hermaphroditic flatworm <i>Macrostomum lignano</i>. We focused on 18 transcripts in <i>M. lignano</i> seminal fluid, testing how their RNA interference-induced knockdown impacted on three aspects of donor (male) reproductive success: (i) fertility (offspring production of the partner); (ii) defensive sperm competitive ability, <i>P</i><sub>1</sub>; and (iii) offensive sperm competitive ability, <i>P</i><sub>2</sub>. In general, the knockdown of most individual transcripts appeared to have only a minor impact on male reproductive success, though we found evidence that the knockdown of up to five different transcripts impacted on fertility; the knockdown of two other transcripts resulted in reduced <i>P</i><sub>2</sub>, and knockdown of a further transcript actually increased <i>P</i><sub>2</sub>. We thus identify a number of candidate seminal fluid transcripts that appear to modulate offspring production and sperm competitiveness in <i>M. lignano</i>. That only a minority of transcripts exhibit such a pattern likely reflects both the difficulty of accurately estimating sperm competitiveness and the functional redundancy of seminal fluid.</p>
Urbanization mediates the effects of water quality and climate on a model aerial insectivorous bird
<p>Aerial insectivorous birds have experienced alarming population declines in eastern North America. Meanwhile, urbanization continues to increase rapidly, with urban land use comprising 69.4 million acres, or 3.6% of total land area, in the contiguous United States. Multiple environmental changes are associated with urbanization, including alterations to local climate, changes in habitat structure, and potential shifts in both terrestrial and emergent aquatic flying insects on which aerial insectivorous birds rely. Here, we investigated the linkages between urbanization, water quality, and Tree Swallow (<i>Tachycineta bicolor</i>) reproductive success and body condition at seven river-riparian sites representing urban and protected land use in Columbus, Ohio over five consecutive years (2014-2018). Tree Swallows at urban and protected sites relied on emergent aquatic insects for 37.4 and 30.8% (SD = 28.4 and 24.1%) of their nutritional subsidies, respectively. Despite the loss of environmental quality generally attributed to cities, Tree Swallows exhibited greater reproductive success in urban settings where climate was more amenable to egg and nestling survival, and the breeding season was longer. Urban-nesting Tree Swallows initiated laying 7.9 days earlier and fledged 35% more young per nest than those at protected sites. Multiple characteristics of urban sites appeared to drive these patterns, including differences in mean and extreme air temperatures and measures of water quality (e.g., water temperature, nutrient concentrations, turbidity). However, chronic effects of elevated Hg concentrations – which were 482% greater in adult swallow blood at urban sites than at protected sites where swallows exhibited a 17.4% lower trophic position – may disadvantage individuals in other ways. Further, although Tree Swallows are a good model aerial insectivore bird species, characteristics of urban landscapes that benefit Tree Swallows may not advantage other aerial insectivorous birds owing to differences in life-history and foraging strategies. These findings implicate urbanization, local climate, and water quality as important considerations in the conservation of aerial insectivorous birds.</p>
Effect of maternal infection on progeny growth and resistance mediated by maternal genotype and nutrient availability
<div class="_3U2q6dcdZCrTrR_42Nxby JWNdg1hee9_Rz6bIGvG1c allowTextSelection"> <div> <div class="BodyFragment"> <div class="PlainText">1. Maternal effects of pathogen infection on progeny development and disease resistance may be adaptive and have important consequences for population dynamics. However, these effects are often context dependent and examples of adaptive transgenerational responses from perennials are scarce, although they may be a particularly important mechanism generating variation in the offspring of long-lived species.</div> <div class="PlainText"> <br> 2. Here, we studied the effect of maternal infection of Plantago lanceolata by Podosphaera plantaginis, a fungal parasite, on the growth, flower production and resistance of the progeny of six maternal genotypes in nutrient rich and poor environments. For this purpose, we combined a common garden study with automated phenotyping measurements of early life-stages, and an inoculation experiment.</div> <div class="PlainText"> <br> 3. Our results show that the effects of infection on the mother plants transcend to impact their progeny. Although maternal infection decreased total leaf and flower production of the progeny by the end of the growing season, it accelerated early growth and enhanced resistance to the pathogen P. plantaginis.</div> <div class="PlainText"> <br> 4. We also discovered that the effects of maternal infection affected progeny development and resistance both directly, and through a three way-interaction between maternal genotype, maternal infection status and nutrient availability.</div> <div class="PlainText"> </div> <div class="PlainText">5. Synthesis: Our results emphasize the importance of maternal effects mediated through genotypic and environmental factors in long living perennials and suggest that maternal infection can create a layer of phenotypic diversity in resistance. These results may have important implications for both epidemiological and evolutionary dynamics of host–parasite interactions in the wild.</div> </div> </div> </div>
Data from: Habitat-mediated carry-over effects lead to context dependent outcomes of species interactions
1. When individuals disperse, their performance in newly colonized habitats can be influenced by the conditions they experienced in the past, leading to environmental carry-over effects. While carry-over effects are ubiquitous in animal and plant systems, their impact on species interactions and coexistence are largely ignored in traditional coexistence theory. 2. Here we used a combination of modelling and experiments with two competing species to examine when and how such environmental carry-over effects influence community dynamics and competitive exclusions. 3. We found that variation in the natal habitat quality of colonizing individuals created carry-over effects which altered competitive coefficients, fecundity and mortality rates, and extinction probabilities of both species. As a consequence, the dynamics of competitive exclusion within and across habitat types was contingent on the natal habitat of colonizing individuals, indicating that spatial carry-over effects can fundamentally alter the dynamics and outcome of interspecific competition. 4. Interestingly, carry-over effects persistently influenced dynamics in systems with interspecific competition for the entire duration of the experiment while carry-over effects were transient and only influenced initial dynamics in single-species populations. Thus carry-over effects can be enhanced by species interactions, suggesting that their long-term effects may often not be accurately predicted by single-species studies. 5. Given that carry-over effects are ubiquitous in heterogeneous landscapes, our results provide a novel mechanism that could help explain variation in the structure of natural communities.
Data from: Individual behaviour mediates effects of warming on movement across a fragmented landscape
Global warming and habitat fragmentation impose dramatic and potentially interactive impacts on ecosystems. Warming induces shifts in species' distributions as they track temperature changes, but this can be hindered in fragmented landscapes. Corridors connecting habitat patches might ameliorate the combined effects of fragmentation and global warming. Using novel automated tracking methods, the movement of woodlice (Oniscus asellus) ranging in body size from 15·3 to 108·6 mg was quantified across a temperature range from 15 to 25 °C as they moved around an experimental fragmented landscape. We used confirmatory path analysis to test causal effects of temperature and body size on individual movement and corridor crossing rates between two habitat patches. Results showed that woodlice behaved differently in corridors than patches by moving, on average, faster and more often. This is congruent with natural systems where corridors generally provide lower quality habitat than patches. Although metabolic theory suggests positive scaling of movement with body temperature (up to a peak) and body size, we found that corridor crossing rate was (i) not directly affected by body size and (ii) negatively influenced by temperature, possibly due to its indirect effects via humidity. Our path model revealed that metabolic scaling could only explain temperature effects on maximum body velocity, but decision-based behaviour explained most variation in corridor crossing rates. This led to direct and indirect effects of temperature and size on individual movement between habitat patches. Our findings suggest that increasing mean global temperatures, coupled with increasing habitat fragmentation, could have synergistic negative impacts on populations through a combination of physiological and behavioural factors that mediate individual responses to temperature and fragmentation.
Data from: Fear mediates trophic cascades: nonconsumptive effects of predators drive aquatic ecosystem function
Predators control prey populations and influence communities and the functioning of ecosystems through a combination of consumptive and nonconsumptive effects. These effects can be locally confined to one ecosystem but can also be extended to neighboring ecosystems. In this study, we investigated the nonconsumptive effects of terrestrial avian predators on the communities of aquatic invertebrates inhabiting bromeliads and on the functioning of these natural ecosystems. Bromeliads with stuffed birds placed nearby showed a decrease in aquatic damselfly larvae abundance and biomass, and we can infer that these changes were caused by antipredator responses. These larvae, which are top predators in bromeliad ecosystems, changed the composition of the entire aquatic invertebrate community. While total species richness, mesopredator richness, and shredder abundance increased in the presence of birds, scraper biomass decreased, possibly as a consequence of the increase in mesopredator richness. High scraper biomass in the absence of birds may have accelerated detrital decomposition, making more nutrients available for bromeliads, which grew more. These results show that nonconsumptive effects triggered by terrestrial predators can cascade down to lower trophic levels and dramatically affect the functioning of aquatic ecosystems, which can in turn alter nutrient provision to terrestrial ecosystems.
Data from: Bottom-up and trait-mediated effects of resource quality on amphibian parasitism
Leaf litter subsidies are important resources for aquatic consumers like tadpoles and snails, causing bottom-up effects on wetland ecosystems. Recent studies have shown that variation in litter nutritional quality can be as important as litter quantity in driving these bottom-up effects. Resource subsidies likely also have indirect and trait-mediated effects on predation and parasitism, but these potential effects remain largely unexplored. We generated predictions for differential effects of litter nutrition and secondary polyphenolic compounds on tadpole (Lithobates sylvatica) exposure and susceptibility to Ribeiroia ondatrae, based on ecological stoichiometry and community-ecology theory. We predicted direct and indirect effects on key traits of the tadpole host (rates of growth, development and survival), the trematode parasite (production of the cercaria infective stages) and the parasite's snail intermediate host (growth and reproduction). To test these predictions, we conducted a large-scale mesocosm experiment using a natural gradient in the concentrations of nutrients (nitrogen) and toxic secondary compounds (polyphenolics) of nine leaf litter species. To differentiate between effects on exposure vs. susceptibility to infection, we included multiple infection experiments including one with constant per capita exposure. We found that increased litter nitrogen increased tadpole survival, and also increased cercaria production by the snail intermediate hosts, causing opposing effects on tadpole per capita exposure to trematode infection. Increased litter polyphenolics slowed tadpole development, leading to increased infection by increasing both their susceptibility to infection and the length of time they were exposed to parasites. Based on these results, recent shifts in forest composition towards more nitrogen-poor litter species should decrease trematode infection in tadpoles via density- and trait-mediated effects on the snail intermediate hosts. However, these shifts also involve increased abundance of litter species with high polyphenolic levels, which should increase trematode infection via trait-mediated effects on tadpoles. Future studies will be needed to determine the relative strength of these opposing effects in natural wetland communities.
Data from: The demographic and life history costs of fear: trait-mediated effects of threat of predation on Aedes triseriatus
1. Predators alter prey populations via direct lethality (density-mediated effects), but in many taxa the indirect nonlethal threat of predation may be almost as strong an effect, altering phenotypically plastic traits such as prey morphology, behaviour, and life history (trait-mediated effects). There are costs to anti-predator defences and the strength of prey responses to cues of predation likely depends on both the perceived level of risk and food availability. 2. The goal of this study was to test the hypothesis that the costs of nonlethal trait-mediated interactions impacting larvae can have carryover effects that alter life history traits, adult characteristics, and ultimately population dynamics. 3. The effects of Toxorhynchites rutilus kairomones and chemical alarm cues on Aedes triseriatus were assessed in a two-level factorial design manipulating nutrient level (low or high) and chemical cues of predation (present or absent). 4. Nonlethal chemical cues of predation significantly decreased female survivorship, and significantly decreased female size. Females emerged as adults significantly earlier when exposed to predation cues when there was high nutrient availability. When raised in the low nutrient treatment and exposed to predator cues adult females had 2.1 times the hazard of death compared to high nutrient-no predator cues. Females raised in the high nutrient and predator cue treatment blood fed sooner than did females from other combinations. 5. Fear of predation can substantially alter prey life history traits and behaviour, which can cascade into dramatic population, community, and ecosystem effects. Exposure to predator cues significantly decreased estimated cohort rate of increase, potentially altering the expected population density of the next generation.
Data from: Invasion-mediated effects on marine trophic interactions in a changing climate: positive feedbacks favour kelp persistence
The interactive effects of ocean warming and invasive species are complex and remain a source of uncertainty for projecting future ecological change. Climate-mediated change to trophic interactions can have pervasive ecological consequences, but the role of invasion in mediating trophic effects is largely unstudied. Using manipulative experiments in replicated outdoor mesocosms, we reveal how near-future ocean warming and macrophyte invasion scenarios interactively impact gastropod grazing intensity and preference for consumption of foundation macroalgae (Ecklonia radiata and Sargassum vestitum). Elevated water temperature increased consumption of both macroalgae through greater grazing intensity. Given the documented decline of kelp (E. radiata) growth at higher water temperatures, enhanced grazing could contribute to the shift from kelp-dominated to Sargasssum-dominated reefs that is occurring at the low-latitude margins of kelp distribution. However, presence of a native invader (Caulerpa filiformis) was related to low consumption by the herbivores on dominant kelp at warmer temperatures. Thus, antagonistic effects between climate change and a range expanding species can favour kelp persistence in a warmer future. Introduction of species should, therefore, not automatically be considered unfavourable under climate change scenarios. Climatic changes are increasing the need for effective management actions to address the interactive effects of multiple stressors and their ecological consequences, rather than single threats in isolation.
Data from: Male-mediated effects on female meiotic recombination
Recombination rates vary owing to an individual's genetic composition and/or its environmental condition. Yet, the effects of mating partner on recombination rates have not been considered. Here, I document a previously undescribed male-mediated effect on female recombination rates. After crossing females to males from different genetic backgrounds, I observed a significant difference in proportion of recombinant offspring based on the genetic background of the father (p=0.0292; 3 df; F=3.07). Genetic variation in male ability to affect recombination rate in their mates suggests the potential for sexual conflict on optimal proportion of recombinant offspring, perhaps leading to changes in population-level recombination rates with varying levels of sexual selection.
Data from: Multi-trophic β-diversity mediates the effect of environmental gradients on the turnover of multiple ecosystem functions
1. Much effort has been devoted to better understanding the effects of environment and biodiversity on ecosystem functioning. However, few studies have moved beyond measuring biodiversity as species richness of a single group and/or focusing on a single ecosystem function. While there is a growing recognition that along environmental gradients, the compositional turnover of multiple trophic groups influences not only productivity but multiple ecosystem functions, we do not know yet which components of multi-trophic β-diversity influence which ecosystem functions. 2. Here, we captured the biodiversity found in soils using environmental DNA to study total soil multi-trophic β-diversity (between all taxa regardless of their trophic group association), horizontal β-diversities (β-diversities within trophic groups) and vertical β-diversity (β-diversity across trophic groups) along a 1000-m elevational gradient in the French Alps. Using path analyses, we quantified how these β-diversity components mediate the effects of environmental turnover on the turnover of multiple ecosystem functions (i.e. productivity, N-cycling, N-leaching) and overall multifunctionality. 3. While we found a strong direct effect of soil properties on the turnover of multiple ecosystem functions, we also found an indirect effect of climate and soil properties through multi-trophic β-diversity. More specifically, only total multi-trophic β-diversity and the horizontal β-diversity of saprophytic fungi were strongly related to the turnover of multifunctionality and, to a lower extent, the turnover of productivity and N-cycling. Our results suggest that decomposition processes and resulting nutrient availability are key to understand how ecosystem functions change along soil properties and climatic gradients in alpine ecosystems. 4. Beyond alpine systems, our study stresses the paramount importance of considering the mediating role of multi-trophic diversity in environmental change impacts on different ecosystem functions and their multifunctionality.
Data from: The effects of spatial structure, frequency dependence and resistance evolution on the dynamics of toxin-mediated microbial invasions
Recent evidence suggests that interference competition between bacteria shapes the distribution of the opportunistic pathogen Staphylococcus aureus in the lower nasal airway of humans, either by preventing colonization or by driving displacement. This competition within the nasal microbial community would add to known host factors that affect colonization. We tested the role of toxin-mediated interference competition in both structured and unstructured environments, by culturing S. aureus with toxin-producing or nonproducing Staphylococcus epidermidis nasal isolates. Toxin-producing S. epidermidis invaded S. aureus populations more successfully than nonproducers, and invasion was promoted by spatial structure. Complete displacement of S. aureus was prevented by the evolution of toxin resistance. Conversely, toxin-producing S. epidermidis restricted S. aureus invasion. Invasion of toxin-producing S. epidermidis populations by S. aureus resulted from the evolution of toxin resistance, which was favoured by high initial frequency and low spatial structure. Enhanced toxin production also evolved in some invading populations of S. epidermidis. Toxin production therefore promoted invasion by, and constrained invasion into, populations of producers. Spatial structure enhanced both of these invasion effects. Our findings suggest that manipulation of the nasal microbial community could be used to limit colonization by S. aureus, which might limit transmission and infection rates.
Data from: Density- and trait-mediated effects of a parasite and a predator in a tri-trophic food web
1. Despite growing interest in ecological consequences of parasitism in food webs, relatively little is known about effects of parasites on long-term population dynamics of non-host species or about whether such effects are density- or trait- mediated. 2. We studied a tri-trophic food chain comprised of: (i) a bacterial basal resource (Serratia fonticola), (ii) an intermediate consumer (Paramecium caudatum), (iii) a top predator (Didinium nasutum), and (iv) a parasite of the intermediate consumer (Holospora undulata). A fully-factorial experimental manipulation of predator and parasite presence/absence was combined with analyses of population dynamics, modelling, and analyses of host (Paramecium) morphology and behavior. 3. Predation and parasitism each reduced the abundance of the intermediate consumer (Paramecium), and parasitism indirectly reduced the abundance of the basal resource (Serratia). However, in combination, predation and parasitism had non-additive effects on the abundance of the intermediate consumer, as well as on that of the basal resource. In both cases, the negative effect of parasitism seemed to be effaced by predation. 4. Infection of the intermediate consumer reduced predator abundance. Modelling and additional experimentation revealed that this was most likely due to parasite reduction of intermediate host abundance (a density-mediated effect), as opposed to changes in predator functional or numerical response. 5. Parasitism altered morphological and behavioural traits, by reducing host cell length and increasing the swimming speed of cells with moderate parasite loads. Additional tests showed no significant difference in Didinium feeding rate on infected and uninfected hosts, suggesting that the combination of these modifications does not affect host vulnerability to predation. However, estimated rates of encounter with Serratia based on these modifications were higher for infected Paramecium than for uninfected Paramecium. 6. A mixture of density-mediated and trait-mediated indirect effects of parasitism on non-host species creates rich and complex possibilities for effects of parasites in food webs that should be included in assessments of possible impacts of parasite eradication or introduction.
Data from: Linking phenological shifts to species interactions through size-mediated priority effects
1. Inter-annual variation in seasonal weather patterns causes shifts in the relative timing of phenological events of species within communities, but we currently lack a mechanistic understanding of how these phenological shifts affect species interactions. Identifying these mechanisms is critical to predicting how inter-annual variation affects populations and communities. 2. Species' phenologies, particularly the timing of offspring arrival, play an important role in the annual cycles of community assembly. We hypothesize that shifts in relative arrival of offspring can alter interspecific interactions through a mechanism called size-mediated priority effects (SMPE), in which individuals that arrive earlier can grow to achieve a body size advantage over those that arrive later. 3. In this study, we used an experimental approach to isolate and quantify the importance of SMPE for species interactions. Specifically, we simulated shifts in relative arrival of the nymphs of two dragonfly species to determine the consequences for their interactions as intraguild predators. 4. We found that shifts in relative arrival altered not only predation strength but also the nature of predator-prey interactions. When arrival differences were great, SMPE allowed the early arriver to prey intensely upon the late arriver, causing exclusion of the late arriver from nearly all habitats. As arrival differences decreased, the early arriver's size advantage also decreased. When arrival differences were smallest, there was mutual predation, and the two species coexisted in similar abundances across habitats. Importantly, we also found a nonlinear scaling relationship between shifts in relative arrival and predation strength. Specifically, small shifts in relative arrival caused large changes in predation strength while subsequent changes had relatively minor effects. 5. These results demonstrate that SMPE can alter not only the outcome of interactions but also the demographic rates of species and the structure of communities. Elucidating the mechanisms that link phenological shifts to species interactions is crucial for understanding the dynamics of seasonal communities as well as for predicting the effects of climate change on these communities.
Data from: Precipitation mediates the effect of human disturbance on the Brazilian Caatinga vegetation
Seasonally dry tropical forests (SDTFs) are one of the most threatened forests worldwide. These species-rich forests not only cope with several acute (e.g. forest loss) and chronic (e.g. overgrazing and firewood extraction) human disturbances, but also with climate change (e.g. longer and more severe droughts); yet, the isolated and combined effects of climate and acute and chronic human disturbances on SDTF vegetation are poorly known. Given the environmental filter imposed by drought in SDTFs, the composition and structure of vegetation is expected to be strongly associated with annual precipitation, and thus the effects of human disturbances on vegetation may also depend on precipitation (i.e. interacting effect). We tested these hypotheses in the Brazilian Caatinga – a SDTF threatened by climate change and human disturbances. We evaluated the isolated and combined (both additive and multiplicative) effect of precipitation, a chronic disturbance index and acute disturbance (landscape forest cover) on the diversity, stem density, evenness, taxonomic composition and aboveground biomass of adult trees and shrubs across 19 0.1-ha plots distributed along a disturbance and precipitation gradients. We recorded 5541 stems from 129 species. Precipitation showed a stronger (positive) effect on species diversity than acute and chronic disturbances and, as expected, the effect of disturbance depended on precipitation (interacting effect): i.e. species diversity (especially the number of rare species) was negatively related to forest loss but positively related to chronic disturbance in wetter sites, whereas in drier sites, species diversity was weakly related to forest cover, but strongly and negatively related to chronic disturbance. Contrary to species diversity, community evenness, stem density and biomass were weakly related to all predictors. Synthesis. Precipitation appears to be a strong environmental filter determining the distribution of water-demanding plant species. Chronic disturbance in wetter (high-productive) forests may favour species diversity by increasing ecosystem heterogeneity (intermediate disturbance hypothesis). Yet, the biodiversity costs of chronic disturbance are higher in drier (low-productive) forests; i.e. there is a co-limitation imposed by drought and disturbance in drier forests. Overall, our findings indicate that rapid climatic changes in the region will probably have strong negative effects on this SDTF.
Data from: Resource composition mediates the effects of intraspecific variability in nutrient recycling on ecosystem processes
Despite the growing evidence for individual variation in trophic niche within populations, its potential indirect effects on ecosystem processes remains poorly understood. In particular, few studies have investigated how intraspecific trophic variability can modulate the effects of consumers on ecosystems through potential changes in nutrient excretion rates. Here, we first quantified the level of intraspecific trophic variability in 11 wild populations of the omnivorous fish Lepomis gibbosus. Outputs from stomach content and stable isotope analyses revealed that the degree of trophic specialization and trophic positions were highly variable between and within these wild populations. There was intrapopulation variation in trophic position of more than one trophic level, suggesting that individuals consumed a range of plant and animal resources. We then experimentally manipulated intraspecific trophic variability to assess how it can modulate consumer-mediated nutrient effects on relevant processes of ecosystem functioning. Specifically, three food sources varying in nutrient quality (e.g. plant material, macro-invertebrate and fish meat) were used individually or in combination to simulate seven diet treatment. Results indicated that intraspecific variability in growth and nitrogen excretion rates were more related to the composition of the diet rather than the degree of specialization, and increased with the trophic position of the diet consumed. We subsequently used microcosms and showed that critical ecosystem functions, such as primary production and community respiration, were affected by the variability in excretory products, and this effect was biomass-dependent. These results highlight the importance of considering variation within species to better assess the effects of individuals on ecosystems and, more specifically, the effects of consumer-mediated nutrient recycling because the body size and the trophic ecology of individuals are affected by a large spectrum of natural and human-induced environmental changes.
Data from: Density-mediated carry-over effects explain variation in breeding output across time in a seasonal population
In seasonal environments, where density dependence can operate throughout the annual cycle, vital rates are typically considered to be a function of the number of individuals at the beginning of each season. However, variation in density in the previous season could also cause surviving individuals to be in poor physiological condition, which could carry over to influence individual success in the following season. We examine this hypothesis using replicated populations of Drosophila melanogaster, the common fruitfly, over 23 non-overlapping generations with distinct breeding and non-breeding seasons. We found that the density at the beginning of the non-breeding season negatively affected the fresh weight of individuals that survived the non-breeding season and resulted in a 25% decrease in per capita breeding output among those that survived to the next season to breed. At the population level, per capita breeding output was best explained by a model that incorporated density at the beginning of the previous non-breeding season (carry-over effect, COE) and density at the beginning of the breeding season. Our results support the idea that density-mediated COEs are critical for understanding population dynamics in seasonal environments.
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These curated guides explain access requirements, typical timelines, costs, and reuse considerations for widely used research datasets.
Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.