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364 results for “Community: dynamics”
In situ soil respirations throughout the 2020 growing season across an N fertilization gradient:Nutrient Network. A cross-site investigation of bottom-up control over herbaceous plant community dynamics and ecosystem function.
This experiment is one implementation of a globally distributed experiment, known as the Nutrient Network. At Cedar Creek, as in over 70 other sites in grasslands around the world, the experiment aims to describe impacts of increased nutrients (nitrogen, phosphorus, potassium, sulfur and other metals) and decreased herbivory (removal of mammals by fencing). Two overarching questions are being explored with these manipulations: 1. To what extent are plant production and diversity co-limited by multiple nutrients in herbaceous-dominated communities? 2. Under what conditions do grazers or fertilization control plant biomass, diversity, and composition? By utilizing identical protocols at diverse grassland sites around the world, NutNet aims to uncover both the generalities in ecosystem functioning, and the contingencies or differences which can obscure those common mechanisms. In addition to the standard NutNet protocol, e247 includes an additional low Nitrogen gradient (1 gram Nitrogen per meter squared per year and 5 grams Nitrogen per meter squared per year in addition to the standard 10 grams Nitrogen per meter squared per year).
Data from: Plant community dynamics and carbon sequestration in Sphagnum-dominated peatlands in the era of global change
<p>Aim: Hydroclimatic shift and anthropogenic-driven nitrogen deposition are major outcomes of global change that could compromise the functioning of many peatlands as a carbon sink. For Sphagnum-dominated peatlands, an emerging hypothesis is that the change could be triggered by shifts in competitive dominance among plant functional groups, specifically from the currently predominant decay-resistant Sphagnum to the more decomposable vascular plants. However, the relationship between Sphagnum and vascular plant occurrence is notably complex and also includes facilitative interactions that are crucial to the productivity of Sphagnum and therefore carbon sequestration.</p> <p>Location: Global</p> <p>Taxa: Northern peatlands—Sphagnum moss and vascular plants</p> <p>Methods: We use a conceptual review to examine underlying mechanisms for the competitive exclusion hypothesis and the nature of facilitative interactions between Sphagnum and vascular plants under the potential global change conditions. We complement the review with an empirical study of peatlands with contrasting hydrology to provide some critical insights into the potential effects of change in plant communities on carbon sequestration. We also propose a conceptual model that presents probable combinations of global change factors and their implications for carbon sequestration.</p> <p>Results: Vegetation structure in Sphagnum-dominated peatland appears to be driven largely by hydrology, rather than competition among plant functional groups. The peat deposit also exerts some controls (e.g., nutrient immobilization) on biotic structure, thereby acting as resistance against an abrupt shift in plant communities.<br> Main conclusions: Peatland controls that constrain vegetation shifts have developed over a millennial timescale in many peatlands, and the pace of climate change may not allow enough time for the establishment of those mechanisms in younger peatlands. Thus, the persistence of a given peatland as a carbon sink also likely depends on the successional stage of the peatland.</p>
Data from: Evolution alters post-invasion temporal dynamics in experimental communities.
<p>1. The causes and consequences of temporal variation in the abundance of organisms constitute central themes in ecological inquiry. Rapid evolution can occur over ecological time scales, potentially resulting in altered temporal variation in abundance and complicating inferences about the consequences of temporal variation. 2. We assessed whether evolution altered the temporal variability in species' abundances in simple assemblages of species. We then compared experimental results to predictions from two-species models to better understand our results in the context of competitive and predator-prey interactions. 3. We compared founder populations and their evolved descendants in experimental communities of ciliates and rotifers. Using a series of orthogonal contrasts, we then evaluated whether: 1) evolutionary history of invaders or 2) residents, 3) coevolution among invaders and residents, and 4) invasion itself altered temporal variability in species abundances following invasion by a novel species. Using two-species competition and predator-prey models, we also generated predictions to better understand the effects of evolution on temporal variation in the abundances of interacting species. Finally, we compared experimental and modeling results to aid in the interpretation of which interspecific interactions might be affected by ongoing evolution in our communities. 4. In experimental populations, differing evolutionary histories resulted in significant differences among treatments in abundances and temporal variation in abundances of both resident and invading species. For the contrasts, we found evidence that evolutionary history of the invader and residents, coevolution among invaders and residents, and invasion itself affected temporal variability in abundance, but the importance of each differed for the two communities and the species within those communities. When comparing experimental results to model predictions, the increased abundance and decreased temporal variation of one invader, <i>Euplotes daidaleos</i>, are potentially consistent with evolution resulting in reduced attack rates in the novel community. 5. Evolutionary history alone can affect temporal variation in the abundances of species, generating important consequences for interspecific interactions among species and complicating inferences about the consequences of temporal variability in biological communities. </p>
Rainfall pulses mediate long-term plant community compositional dynamics in a semi-arid rangeland
<p>1. Semi-arid rangelands, comprising more than 40% of the Earth's land surface, provide critical ecosystem services. Worldwide, these ecosystems are experiencing rapid degradation due to overgrazing and precipitation changes. However, how plants respond to these interacting factors remains relatively unexplored, and precisely which and how rainfall factors determine plant community dynamics in rangelands has not been well developed.</p> <p>2. We used a long-term (1953‒2018) dataset from semi-arid rangeland to investigate coupled effects of grazing intensity and rainfall intensity (the total amount of precipitation) on different groups of plant cover (herbaceous, woody, and cacti plants) using linear mixed-effects models, redundancy analysis and structural equation models. We examined how rainfall intensity influenced plant cover dynamics according to pulse size (intensity over time) categories, which we analyzed at three scales: yearly, within the wet season only (June to September), and within the dry season only (October to May). </p> <p>3. Plant community cover showed a humpbacked trend in the last six decades, mostly through changes in woody plants. Although both grazing intensity and rainfall presented similar humpbacked trends with plant community cover, our models demonstrated that the reduction of plant cover from the 1990s has been mainly caused by a decrease of rainfall rather than grazing intensity, particularly due to profound reductions of the intensity of relatively small rainfall pulses (e.g., 5.1 ~ 15 mm·day<sup>-1</sup>) during the dry season. Specifically, these small rainfall pulses can increase plant cover of all subgroups of woody and herbaceous species, thereby increasing plant community cover. Moreover, rainfall pulses during the wet season had negative effects on herbaceous species and positive effects on woody plants. These results suggest a phenological niche partitioning between woody plants and herbaceous in subtropical rangelands.</p> <p>4. <i>Synthesis and applications.</i><b> </b>Our results show how critical seasonal rainfall pulses are for regulating plant community compositional dynamics, which has significant implications for rangeland management and our ability to adapt and mitigate amplified climate influences in semi-arid ecosystems.</p>
Data supporting the manuscript "Initial assemblage characteristics determine the functional dynamics of flower-strip plant communities"
<p>Original data recorded by the authors.</p>
Multi-decadal shifts in fish community diversity across a dynamic biogeographic transition zone
<p><b><span>Aim: </span></b><span>A 21-year fisheries-independent monitoring dataset was used to explore fish community diversity across a latitudinal gradient to quantify how diversity has changed and relate those changes in diversity to changes in the abiotic environment. Additionally, this study spans a biogeographic transition zone, providing insight into future species assemblages across regions of relatively high species diversity.</span></p> <p><b><span>Location: </span></b><span>Indian River Lagoon, Florida, USA</span></p> <p><b><span>Methods: </span></b><span>Spatial and temporal beta diversity<b> </b>was quantified latitudinally with "best derived breaks" determined by using chronological cluster analyses. Multiple indices of alpha diversity were quantified, including species richness, Shannon diversity, Simpson diversity, and Pielou's evenness. AIC model selection and environmental fit tests were performed to link patterns of diversity and species assemblages with the abiotic environment. </span></p> <p><b><span>Results: </span></b><span>Evidence of a biogeographic transition zone was supported by data spanning the entire study period; the largest break in species assemblage occurred near 28</span><span>°</span><span>N. Fine scale analyses using small and large seine catches were noisier than broad analyses but indicated a northern shift in location of the biogeographic transition zone. Beta-diversity was generally dominated by species turnover/balance versus nestedness/gradient components, implying that changes were driven by species sorting associated with the physical environment. Excluding the summation of all environmental variables, temperature and dissolved oxygen best describe patterns of diversity and species composition. </span></p> <p><b><span>Main Conclusions: </span></b><span>Over years less affected by disturbances, large and small seine catch data suggest the fish community assemblage and location of the biogeographic transition zone has shifted 9 km and 21 km to the north. If the trends observed in these years were to continue from 1999 until the year 2100, a 111 km to 243 km shift in fish communities could be expected. Variation in rates of movement based on gear type suggest novel species assemblages could ensue.</span></p>
Data from: Stream community richness predicts apex predator occupancy dynamics in riparian systems
Streams and adjacent riparian habitats represent linked terrestrial and aquatic ecosystems that exchange materials and energy. Recognized relationships among apex predators and ecosystem biodiversity led us to hypothesize that these predators in riparian-stream systems were more likely to be found in sites with high stream quality, defined as increased ecosystem function and integrity. In our freshwater study system, river otter (Lontra canadensis) and mink (Neovison vison) play critical roles as apex predators. We used multi-season occupancy modelling across 3 sampling years (2012-2014) to compare aspects of the stream communities that explain occupancy dynamics of river otter and mink, including their interactions with other semi-aquatic mammals. We surveyed for semi-aquatic mammals at 77 sites in 12 major watersheds in southern Illinois, USA (44,526 km<sup>2</sup>). Naïve occupancy differed among years but generally increased for river otter, and remained high (≥93.5%) for mink. Increasing substrate availability increased detectability of river otter, whereas mink detection varied by survey period. Occupancy of river otter during the initial survey period was higher in sites closer to reintroduction points. Probability of colonization of river otter was positively associated with macroinvertebrate index of biotic integrity, fish species richness, and beaver presence. Sites with high species richness of fish families preferred by river otter also had increased river otter persistence. Mink occupied sites with increased fish richness, muskrat presence, and mussel community index. Taken together, our results show occupancy of both mink and river otter were predicted by aspects of prey diversity and presence, indicating the importance of community composition in occupancy dynamics of riparian predators. Ultimately, these relationships suggest that habitat heterogeneity and system stability are important to apex predator site use. However, the relative role of bottom-up and top-down forcing in stream systems remains to be resolved.
Data from: Colonize, radiate, decline: unraveling the dynamics of island community assembly with Fijian trap-jaw ants
<p>The study of island community assembly has been fertile ground for developing and testing theoretical ideas in ecology and evolution. The eco-evolutionary trajectory of lineages after colonization has been a particular interest, as this is a key component of understanding community assembly. In this system, existing ideas such as the taxon cycle posit that lineages pass through a regular sequence of eco-evolutionary changes after colonization, with lineages shifting toward reduced dispersal ability, increased ecological specialization, and declines in abundance. However, these predictions have historically been difficult to test. Here, we integrate phylogenomics, population genomics, and x-ray microtomography/3D morphometrics, to test hypotheses for whether the ecomorphological diversity of trap-jaw ants (<i>Strumigenys</i>) in the Fijian archipelago is assembled primarily through colonization or post-colonization radiation, and whether species show ecological shifts toward niche specialization, toward upland habitats, and decline in abundance after colonization. We infer that most Fijian endemic <i>Strumigenys</i> evolved <i>in situ</i> from a single colonization and have diversified to fill a large fraction of global morphospace occupied by the genus. Within this adaptive radiation, lineages trend to different degrees toward high elevation, reduced dispersal ability, and demographic decline, and we find no evidence of repeated colonization that displaces the initial radiation. Overall these results are only partially consistent with taxon cycle and associated ideas, while highlighting the potential role of priority effects in assembling island communities.</p>
Data from: Temporal dynamics of encrusting communities during the Late Devonian: a case study from the Central Devonian Field, Russia
In this study we focused on the dynamics of encrusting assemblages preserved on brachiopod hosts collected from upper Frasnian and lower Famennian deposits of the Central Devonian Field, Russia. Because the encrusted brachiopods come from deposits bracketing the Frasnian/Famennian (F/F) boundary, the results also shed some light on ecological differences in encrusting communities before and after the Frasnian–Famennian (F-F) event. To explore the diversity dynamics of encrusting assemblages, we analyzed more than 1300 brachiopod valves (substrates) from two localities. Taxon accumulation plots and shareholder quorum subsampling (SQS) routines indicated that a reasonably small sample of brachiopod host valves (n=50) is sufficient to capture the majority of the encrusting genera recorded at a given site. The richness of encrusters per substrate declined simultaneously with the number of encrusting taxa in the lower Famennian, accompanied by a decrease in epibiont abundance, with a comparable decrease in mean encrustation intensity (percentage of bioclasts encrusted by one or more epibionts). Epibiont abundance and occupancy roughly mirror each other. Strikingly, few ecological characteristics are correlated with substrate size, possibly reflecting random settlement of larvae. Evenness, which is negatively correlated with substrate size, shows greater within-stage variability among samples than between Frasnian and Famennian intervals and may indicate the instability of early Famennian biocenoses following the faunal turnover. The occurrence distribution of encrusters points to nonrandom associations and exclusions among several encrusting taxa. However, abundance and occupancy of microconchids remained relatively stable throughout the sampled time interval. The notable decline in abundance (~60%) and relatively minor decline in diversity (~30%) suggest jointly that encrusting communities experienced ecological collapse rather than a major mass extinction event. The differences between the upper Frasnian and lower Famennian encrusting assemblages may thus record a turnover associated with the F-F event.
Data from: Strategies of zooplanktivory shape dynamics and diversity of littoral plankton communities: a mesocosm approach
Planktivorous fish can exert strong top-down control on zooplankton communities. By incorporating different feeding strategies, from selective particulate feeding to cruising filter feeding, fish species target distinct prey. In this study, we investigated the effects of two species with different feeding strategies, the three-spined stickleback (Gasterosteus aculeatus (L.)) and roach (Rutilus rutilus (L.)), on a low-diversity brackish water zooplankton community using a 16-day mesocosm experiment. The experiment was conducted on a small-bodied spring zooplankton community in high-nutrient conditions, as well as a large-bodied summer community in low-nutrient conditions. Effects were highly dependent on the initial zooplankton community structure and hence seasonal variation. In a small-bodied community with high predation pressure and no dispersal or migration, the selective particulate-feeding stickleback depleted the zooplankton community and decreased its diversity more radically than the cruising filter-feeding roach. Cladocerans rather than copepods were efficiently removed by predation, and their removal caused altered patterns in rotifer abundance. In a large-bodied summer community with initial high taxonomic and functional diversity, predation pressure was lower and resource availability was high for omnivorous crustaceans preying on other zooplankton. In this community, predation maintained diversity, regardless of predator species. During both experimental periods, predation influenced the competitive relationship between the dominant calanoid copepods, and altered species composition and size structure of the zooplankton community. Changes also occurred to an extent at the level of nontarget prey, such as microzooplankton and rotifers, emphasizing the importance of subtle predation effects. We discuss our results in the context of the adaptive foraging mechanism and relate them to the natural littoral community.
Data from: Combining fish and benthic communities into multiple regimes reveals complex reef dynamics
Coral reefs worldwide face an uncertain future with many reefs reported to transition from being dominated by corals to macroalgae. However, given the complexity and diversity of the ecosystem, research on how regimes vary spatially and temporally is needed. Reef regimes are most often characterised by their benthic components; however, complex dynamics are associated with losses and gains in both fish and benthic assemblages. To capture this complexity, we synthesised 3,345 surveys from Hawai'i to define reef regimes in terms of both fish and benthic assemblages. Model-based clustering revealed five distinct regimes that varied ecologically, and were spatially heterogeneous by island, depth and exposure. We identified a regime characteristic of a degraded state with low coral cover and fish biomass, one that had low coral but high fish biomass, as well as three other regimes that varied significantly in their ecology but were previously considered a single coral dominated regime. Analyses of time series data reflected complex system dynamics, with multiple transitions among regimes that were a function of both local and global stressors. Coupling fish and benthic communities into reef regimes to capture complex dynamics holds promise for monitoring reef change and guiding ecosystem-based management of coral reefs.
Data from: Spatial-temporal dynamics of Neotropical velvet ant (Hymenoptera: Mutillidae) communities along a forest-savanna gradient
Understanding how and why biological communities are organized over space and time is a major challenge and can aid biodiversity conservation in times of global changes. Herein, spatial-temporal variation in the structure of velvet ant communities was examined along a forest-savanna gradient in the Brazilian Cerrado to assess the roles of environmental filters and interspecific interactions upon community assembly. Velvet ants were sampled using 25 arrays of Y-shaped pitfall traps with drift fences for one year along an environmental gradient from cerrado sensu stricto (open canopy, warmer, drier) to cerradão (closed canopy, cooler, moister). Dataloggers installed on each trap recorded microclimate parameters throughout the study period. The effects of spatial distances, microclimate parameters and shared ancestry on species abundances and turnover were assessed with canonical correspondence analysis, generalized dissimilarity modelling and variance components analysis. Velvet ant diversity and abundance were higher in the cerrado sensu stricto and early in the wet season. There was pronounced compositional turnover along the environmental gradient, and temporal variation in richness and abundance was stronger than spatial variation. The dry season blooming of woody plant species fosters host abundance and, subsequently, velvet ant captures. Species were taxonomically clustered along the gradient with Sphaeropthalmina (especially Traumatomutilla spp.) and Pseudomethocina more associated, respectively, with cerrado sensu stricto and cerradão. This suggests a predominant role of environmental filters on community assemble, with physiological tolerances and host preferences being shared among members of the same lineages. Induced environmental changes in Cerrado can impact communities of wasps and their hosts with unpredictable consequences upon ecosystem functioning and services.
Data from: Variable sea-ice conditions influence trophic dynamics in an Arctic community of marine top predators
Sea‐ice coverage is a key abiotic driver of annual environmental conditions in Arctic marine ecosystems and could be a major factor affecting seabird trophic dynamics. Using stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in eggs of thick‐billed murres (Uria lomvia), northern fulmars (Fulmarus glacialis), glaucous gulls (Larus hyperboreus), and black‐legged kittiwakes (Rissa tridactyla), we investigated the trophic ecology of prebreeding seabirds nesting at Prince Leopold Island, Nunavut, and its relationship with sea‐ice conditions. The seabird community of Prince Leopold Island had a broader isotopic niche during lower sea‐ice conditions, thus having a more divergent diet, while the opposite was observed during years with more extensive sea‐ice conditions. Species' trophic position was influenced by sea ice; in years of lower sea‐ice concentration, gulls and kittiwakes foraged at higher trophic levels while the opposite was observed for murres and fulmars. For murres and fulmars over a longer time series, there was no evidence of the effect of sea‐ice concentration on species' isotopic niche. Results suggest a high degree of adaptation in populations of high Arctic species that cope with harsh and unpredictable conditions. Such different responses of the community isotopic niche also show that the effect of variable sea‐ice conditions, despite being subtle at the species level, might have larger implications when considering the trophic ecology of the larger seabird community. Species‐specific responses in foraging patterns, in particular trophic position in relation to sea ice, are critical to understanding effects of ecosystem change predicted for a changing climate.
Data from: Diversity dynamics of Phanerozoic terrestrial tetrapods at the local-community scale
The fossil record provides one of the strongest tests of the hypothesis that diversity within local communities is constrained over geological timescales. Constraints to diversity are particularly controversial in modern terrestrial ecosystems, yet long-term patterns are poorly understood. Here we document patterns of local richness in Phanerozoic terrestrial tetrapods using a global data set comprising 145,332 taxon occurrences from 27,531 collections. We show that the local richness of non-flying terrestrial tetrapods has risen asymptotically since their initial colonization of land, increasing at most threefold over the last 300 million years. Statistical comparisons support phase-shift models, with most increases in local richness occurring: (1) during the colonization of land by vertebrates, concluding by the late Carboniferous; and (2) across the Cretaceous/Paleogene boundary. Individual groups, such as mammals, lepidosaurs and dinosaurs also experienced early increases followed by periods of stasis often lasting tens of millions of years. Mammal local richness abruptly tripled across the Cretaceous/Paleogene boundary, but did not increase over the next 66 million years. These patterns are consistent with the hypothesis that diversity is constrained at the local-community scale.
Data from: Synchrony in small mammal community dynamics across a forested landscape
Long-term studies at local scales indicate that fluctuations in abundance among trophically similar species are often temporally synchronized. Complementary studies on synchrony across larger spatial extents are less common, as are studies that investigate the subsequent impacts on community dynamics across the landscape. We investigate the impact of species population fluctuations on concordance in community dynamics for the small mammal fauna of the White Mountain National Forest, USA. Hierarchical open population models, which account for imperfect detection, were used to model abundance of the most common species at 108 sites over a three year period. Most species displayed individualistic responses of abundance to forest type and physiographic characteristics. However, among species, we found marked synchrony in population fluctuations across years, regardless of landscape affinities or trophic level. Across the region, this population synchrony led to high within-year concordance of community composition and aggregate properties (e.g., richness and diversity) independent of forest type and low among-year similarity in communities, even for years with similar species richness. Results suggest that extrinsic factors primarily drive abundance fluctuations and subsequently community dynamics, although local community assembly may be modified by species dispersal abilities and biotic interactions. Concordant community dynamics across space and over time may impact the stability of regional food webs and ecosystem functions.
Data from: Effect of insect herbivory on plant community dynamics under contrasting water availability levels
1. Diversity of plant communities is impacted by multiple global change drivers but also by altered biotic interactions with antagonist and mutualist organisms that can potentially affect species coexistence. 2. With a two-year outdoor mesocosm experiment in realistic mesic grassland communities, we explored the role of insect herbivory in impacting plant community dynamics under contrasting levels of water availability simulating altered rainfall regimes. We selected a grasshopper species (Calliptamus italicus) feeding predominantly on forbs while avoiding grasses. 3. High water availability reduced species coexistence, boosting productivity while decreasing individual plant survival. At the community level, herbivores were not able to promote species coexistence but asymmetrically influenced grasses and forbs, reducing forb biomass under high water availability. 4. Herbivores shaped individual plant responses to both abiotic conditions and individual-neighbours' interactions. Herbivores influenced focal plant survival by altering the effect of neighbouring plants, mitigating the negative effect of high neighbour biomass at low water availability and exacerbating it at high level of water availability. 5. Synthesis: Altered rainfall has the capacity to change the relative strength of the plant-plant interactions and also to determine the effects of herbivores on grassland communities. The complexity of the interactions between plants and herbivores and the observed context-dependence indicate the need to incorporate multiple biotic and abiotic drivers to fully understand the mechanisms underlying plant dynamics and species coexistence in a changing world.
Data from: Animals alter precipitation legacies: trophic and ecosystem engineering effects on plant community temporal dynamics
1. Multi-year precipitation 'legacies' can have stronger effects on plant community composition than rainfall in the current growing season, but variation in the magnitude of these effects is not fully understood. Direct interactions between plants and animals, such as herbivory, and indirect interactions, such as ecosystem engineering (via changes in the physical environment), may influence precipitation legacies by altering mechanisms of lagged effects. However, the role of direct and indirect plant-animal interactions in determining the strength of precipitation legacies remains largely unexplored. 2. Here, we investigated effects of current growing season rainfall and precipitation legacies on grassland composition, and the influence of herbivory and ecosystem engineering interactions on these temporal dynamics. From 2009 to 2014, a period spanning high and low rainfall, we recorded plant cover in kangaroo rat exclosures and paired control plots that included both burrow and inter-burrow areas. We used linear mixed effects modeling and analysis of community dissimilarities to evaluate plant composition responses to current and previous growing season rainfall and kangaroo rat herbivory (presence of seed foraging) and ecosystem engineering (burrowing). 3. We found that community composition was more strongly affected by precipitation legacies than by current growing season rainfall. Greater precipitation in the previous growing season enhanced grass cover and reduced forb and legume cover. Kangaroo rat trophic and engineering interactions had counteracting effects on these legacies. While burrowing increased grass cover and thereby amplified the effects of previous growing season rainfall on community composition, legacies were suppressed by the presence of kangaroo rat foraging, which decreased grass cover. Further analysis revealed that kangaroo rat foraging and burrowing had conflicting effects on residual plant biomass prior to the growing season, suggesting that precipitation legacies were influenced by altered litter dynamics. 4. Synthesis. Our study demonstrates that animals can impact the strength of precipitation legacies through direct and indirect interactions with the plant species that drive lag effects. The influence of multiple types of plant-animal interactions on precipitation legacies may be important to consider for ecosystem management and when generating predictions of community composition and productivity in future ecosystems.
Data from: Seasonal dynamics and changing sea level as determinants of the community and trophic structure of oribatid mites in a salt marsh of the Wadden Sea
Global change processes affect seasonal dynamics of salt marshes and thereby their plant and animal communities. However, these changes have been little investigated for microarthropod communities. We studied the effect of seasonality and changes in sea level on oribatid mites in the natural salt marsh and on artificial islands in the back-barrier environment of the island Spiekeroog (Wadden Sea, Germany). Three zones of the artificial islands were filled with transplanted sods from the lower salt marsh zone and thereby exposed to three different inundation frequencies. We hypothesized that oribatid mite communities will differ along the natural salt marsh vegetation zones [upper salt marsh (USM), lower salt marsh (LSM), pioneer zone (PZ)], which are influenced by different tidal regimes. Accordingly, total oribatid mite densities declined from the USM and LSM to the PZ. Similarly, oribatid mite species compositions changed along the salt marsh transect and also responded to variations in inundation frequency in LSM on artificial islands with typical species of the USM, LSM and PZ being Multioppia neglecta (USM), Hermannia pulchella (LSM), Zachvatkinibates quadrivertex (LSM, PZ) and Ameronothrus schneideri (LSM, PZ). Oribatid mite density in the salt marsh and on the artificial islands was at a maximum in winter and spring; this was due in part to high density of juveniles, pointing to two reproductive periods. We hypothesized that oribatid mite trophic structure changes due to variations in abiotic (e.g., tidal dynamics, temperature) and biotic conditions (e.g., resource availability). Stable isotope (15N, 13C) and neutral lipid fatty acid analyses indicated that oribatid mite species have different diets with e.g., Z. quadrivertex feeding on macroalgae and fungi, A. schneideri feeding on microalgae and bacteria, and Scheloribates laevigatus and M. neglecta feeding on dead organic matter, bacteria and fungi. Overall, the results indicate that oribatid mite species in salt marshes are affected by changes in environmental factors such as inundation intensity, with the effects being most pronounced in species with narrow trophic niches and limited niche plasticity. The results also indicate that oribatid communities of the LSM respond little to short-term (one year) changes in inundation frequency.
Data from: Chronic nitrogen addition induces a cascade of plant community responses with both seasonal and progressive dynamics
Short-lived herbaceous plants provide a useful model to rapidly reveal how multiple generations of plants in natural plant communities of sensitive desert ecosystems will be affected by N deposition. We monitored dynamic responses of community structure, richness, evenness, density and biomass of herbaceous plants to experimental N addition (2:1 NH4+:NO3− added at 0, 0.5, 1, 3, 6 and 24 g N m− 2 a− 1) in three seasons in each of three years in the Gurbantunggut desert, a typical temperate desert of central Asia. We found clear rate-dependent and season-dependent effects of N deposition on each of these variables, in most cases becoming more obvious through time. N addition reduced plant richness, leading to a loss of about half of the species after three generations in the highest N application level. Evenness and density were relatively insensitive to all but the greatest levels of N addition for two generations, but negative effects emerged in the third generation. Biomass, both above and below ground, was non-linearly affected by N deposition. Low and intermediate levels of N deposition often increased biomass, whereas the highest level suppressed biomass. Stimulatory effects of intermediate N addition disappeared in the third generation. All of these responses are strongly interrelated in a cascade of changes. Notably, changes in biomass due to N deposition were mediated by declines in richness and evenness, and other changes in community structure, rather than solely being the direct outcome of release from limitation. The interrelationships between N deposition and the different plant community attributes change not only seasonally, but also progressively change through time. These temporal changes appear to be largely independent of interannual or seasonal climatic conditions.
Data from: A new integrative framework for large-scale assessments of biodiversity and community dynamics, using littoral gastropods and crabs of British Columbia, Canada
Improving our understanding of species responses to environmental changes is an important contribution ecologists can make to facilitate effective management decisions. Novel synthetic approaches to assessing biodiversity and ecosystem integrity are needed, ideally including all species living in a community and the dynamics defining their ecological relationships. Here we present and apply an integrative approach that links high-throughput, multi-character taxonomy with community ecology. The overall purpose is to enable the coupling of biodiversity assessments with investigations into the nature of ecological interactions in a community-level data set. We collected 1,195 gastropods and crabs in British Columbia. First, the General mixed Yule-coalescent (GMYC) and the Poisson Tree Processes (PTP) methods for proposing primary species-hypotheses based on cox1 sequences were evaluated against an integrative taxonomic framework. We then used data on the geographic distribution of delineated species to test species co-occurrence patterns for non-randomness using community-wide and pairwise approaches. Results showed that PTP generally outperformed GMYC and thus constitutes a more effective option for producing species-hypotheses in community-level datasets. Non-random species co-occurrence patterns indicative of ecological relationships or habitat preferences were observed for grazer gastropods, whereas assemblages of opportunistic omnivorous gastropods and crabs appeared influenced by random processes. Species-pair associations were consistent with current ecological knowledge, thus suggesting that applying community assembly within a large taxonomical framework constitutes a valuable tool for assessing ecological interactions. Combining phylogenetic, morphological and co-occurrence data enabled an integrated view of communities, providing both a conceptual and pragmatic framework for biodiversity assessments and investigations into community dynamics.
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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.