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11,506 results for “Dynamics”
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: The dynamics of Kelp Forests in the Northeast Pacific Ocean and the relationship with environmental drivers
1.The dynamics of foundation species in ecosystems are key to the fate of many species. Kelp forests are foundation species in temperate ocean ecosystems and contribute to carbon storage, macronutrient dynamics, primary production, and biodiversity of myriad associated species. Downward trends in their abundance globally have been of concern. 2.We analyzed 26 years of aerial censuses (1989-2015) of 2 canopy kelp species in Washington State (USA) waters. We compared these modern censuses with censuses in 1911 and 1912 to determine the persistence of kelp cover over the past century. Using Auto-regressive Integrated Moving Average (ARIMA) models, we compared kelp dynamics with likely environmental drivers, including local environmental variables and ocean indices for this region. 3.Kelp remains at historic levels in many areas, though some eastern populations in proximity to greater human populations are the exception to this pattern. Over the last 26 years, kelp abundance showed high spatial autocorrelation in western areas of Straits of Juan de Fuca, with more variable populations in the annual species and eastward toward Puget Sound. Both species covaried positively in their abundance throughout most of the study area, suggesting environmental factors rather than competition, drove their dynamics. The population dynamics of these kelp species showed that the abundance one year previous was an important predictor, and cyclic dynamics were not indicated using Auto-regressive Integrated Moving Average (ARIMA) models. Kelp abundance correlated inversely with the Pacific Decadal Oscillation and the Oceanic Nino Index, and positively with the North Pacific Gyre Oscillation, indicating that large-scale processes associated with colder seawater temperatures were associated with greater relative abundance of kelp. 4.Synthesis. Kelp beds in the northern California Current Large Marine Ecosystem have mostly remained persistent over the past century and over many km, but some areas may have decreased in abundance. The sensitivity of these populations to indices of ocean climate, our demonstration that a historic 93-year SST record (Race Rocks, Canada) showed a 0.72°C increase, and the classification of some areas as high variability-low abundance, suggest that the viability of these foundational species remain a concern into the future.
Occupancy in dynamic systems: accounting for multiple scales and false positives using environmental DNA to inform monitoring
<div class="page"> <div class="section"> <p>Occupancy is an important metric to understand current and future trends in populations that have declined globally. In addition, occupancy can be an efficient tool for conducting landscape-scale and long-term monitoring. A challenge for occupancy monitoring programs is to determine the appropriate spatial scale of analysis and to obtain precise occupancy estimates for elusive species. We used a multi-scale occupancy model to assess occupancy of Columbia spotted frogs in the Great Basin, USA, based on environmental DNA (eDNA) detections. We collected three replicate eDNA samples at 220 sites across the Great Basin. We estimated and modeled ecological factors that described watershed and site occupancy at multiple spatial scales simultaneously while accounting for imperfect detection. Additionally, we conducted visual and dipnet surveys at all sites and used our paired detections to estimate the probability of a false positive detection for our eDNA sampling. We applied the estimated false positive rate to our multi-scale occupancy dataset and assessed changes in model selection. We had higher naïve occupancy estimates for eDNA (0.37) than for traditional survey methods (0.20). We estimated our false positive detection rate per qPCR replicate at 0.023 (95% CI: 0.016-0.033). When the false positive rate was applied to the multi-scale dataset, we did not observe substantial changes in model selection or parameter estimates. Conservation and resource managers have an increasing need to understand species occupancy in highly variable landscapes where the spatial distribution of habitat changes significantly over time due to climate change and human impact. A multi-scale occupancy approach can be used to obtain regional occupancy estimates that can account for spatially dynamic differences in availability over time, especially when assessing potential declines. Additionally, this study demonstrates how eDNA can be used as an effective tool for improved occupancy estimates across broad geographic scales for long-term monitoring.</p> </div> </div>
Data from: Microbe biogeography tracks water masses in a dynamic oceanic frontal system
PLEASE NOTE, THESE DATA ARE ALSO REFERRED TO IN ANOTHER PUBLICATION. PLEASE SEE http://dx.doi.org/10.1098/rsos.160829. Dispersal limitation, not just environmental selection, plays an important role in microbial biogeography. The distance–decay relationship is thought to be weak in habitats where dispersal is high, such as in the pelagic environment, where ocean currents facilitate microbial dispersal. Most studies of microbial community composition to date have observed little geographical heterogeneity on a regional scale (100 km). We present a study of microbial communities across a dynamic frontal zone in the southwest Indian Ocean and investigate the spatial structure of the microbes with respect to the different water masses separated by these fronts. We collected 153 samples of free-living microorganisms from five seamounts located along a gradient from subtropical to subantarctic waters and across three depth layers: (i) the sub-surface chlorophyll maximum (approx. 40 m), (ii) the bottom of the euphotic zone (approx. 200 m), and (iii) the benthic boundary layer (300–2000 m). Diversity and abundance of microbial operational taxonomic units (OTUs) were assessed by amplification and sequencing of the 16S rRNA gene on an Illumina MiSeq platform. Multivariate analyses showed that microbial communities were structured more strongly by depth than by latitude, with similar phyla occurring within each depth stratum across seamounts. The deep layer was homogeneous across the entire survey area, corresponding to the spread of Antarctic intermediate water. However, within both the sub-surface layer and the intermediate depth stratum there was evidence for OTU turnover across fronts. The microbiome of these layers appears to be divided into three distinct biological regimes corresponding to the subantarctic surface water, the convergence zone and subtropical. We show that microbial biogeography across depth and latitudinal gradients is linked to the water masses the microbes persist in, resulting in regional patterns of microbial biogeography that correspond to the regional scale physical oceanography.
Data from: Modeling effects of environmental change on wolf population dynamics, trait evolution, and life history
Environmental change has been observed to generate simultaneous responses in population dynamics, life history, gene frequencies, and morphology in a number of species. But how common are such eco-evolutionary responses to environmental change likely to be? Are they inevitable, or do they require a specific type of change? Can we accurately predict eco-evolutionary responses? We address these questions using theory and data from the study of Yellowstone wolves. We show that environmental change is expected to generate eco-evolutionary change, that changes in the average environment will affect wolves to a greater extent than changes in how variable it is, and that accurate prediction of the consequences of environmental change will probably prove elusive.
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: Field crickets compensate for unattractive static long-distance call components by increasing dynamic signalling effort
The evolution of multiple sexual signals presents a dilemma since individuals selecting a mate should pay attention to the most honest signal and ignore the rest; however, multiple signals may evolve if, together, they provide more information to the receiver than either one would alone. Static and dynamic signals, for instance, can act as multiple messages, providing information on different aspects of signaller quality that reflect condition at different time scales. While the nature of static signals makes them difficult or impossible for individuals to augment, dynamic signals are much more susceptible to temporary fluctuations in effort. We investigated whether male Texas field crickets, Gryllus texensis, that produce unattractive static signals compensate by dynamically increasing their calling effort. Our findings lend partial support to the compensation hypothesis, as males that called at unattractive carrier frequencies (a static trait) spent more time calling each night (a dynamic trait). Interestingly, this finding was most pronounced in males that called with attractive pulse characteristics (static traits) but did not occur in males that called with unattractive pulse characteristics. Males that signalled with unattractive pulse characteristics (duration and pause) spent less time calling through the night. Our correlative findings on wild caught males suggest that only males that signal with attractive pulse characteristics may be able to afford to pay the costs of both trait exaggeration and increased calling effort to compensate for poor carrier frequencies.
Data from: Metapopulation dynamics of the mistletoe and its host in savanna areas with different fire occurrence
Mistletoes are aerial hemiparasitic plants which occupy patches of favorable habitat (host trees) surrounded by unfavorable habitat and may be possibly modeled as a metapopulation. A metapopulation is defined as a subdivided population that persists due to the balance between colonization and extinction in discrete habitat patches. Our aim was to evaluate the dynamics of the mistletoe Psittacanthus robustus and its host Vochysia thyrsoidea in three Brazilian savanna areas using a metapopulation approach. We also evaluated how the differences in terms of fire occurrence affected the dynamic of those populations (two areas burned during the study and one was fire protected). We monitored the populations at six-month intervals. P. robustus population structure and dynamics met the expected criteria for a metapopulation: i) the suitable habitats for the mistletoe occur in discrete patches; (ii) local populations went extinct during the study and (iii) colonization of previously non-occupied patches occurred. The ratio of occupied patches decreased in all areas with time. Local mistletoe populations went extinct due to two different causes: patch extinction in area with no fire and fire killing in the burned areas. In a burned area, the largest decrease of occupied patch ratios occurred due to a fire event that killed the parasites without, however, killing the host trees. The greatest mortality of V. thyrsoidea occurred in the area without fire. In this area, all the dead trees supported mistletoe individuals and no mortality was observed for parasite-free trees. Because P. robustus is a fire sensitive species and V. thyrsoidea is fire tolerant, P. robustus seems to increase host mortality, but its effect is lessened by periodic burning that reduces the parasite loads.
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: Molecular ecology of the Neotropical otter (Lontra longicaudis): non-invasive sampling yields insights into local population dynamics
Non-invasive genetic analysis has been frequently employed to estimate ecological and population parameters for many secretive and/or threatened species. However, Neotropical carnivores have so far been scarcely targeted by such studies. The Neotropical otter (Lontra longicaudis) is a poorly-known species for which local levels of genetic diversity and demographic parameters are virtually absent. We employed non-invasive sampling and amplification of microsatellite loci to investigate population size and density, spatial organization, and relatedness of a wild Neotropical otter population in an Atlantic forest area in southern Brazil. We directly identified 28 individuals and estimate a rather high population density at the study site. Spatial organization analysis indicated that male cumulative displacement was higher than that of females, with the latter sex showing evidence of philopatric behaviour. Also, the reconstruction of genealogical relationships suggests that spatial organization in this otter appears to be influenced by relatedness. By allowing the testing of specific hypothesis targeting these issues, our results provided important glimpses into the Neotropical otter's population biology. Moreover, the findings of the present study reaffirm the power of non-invasive genetics to investigate the biology of this elusive species, and open up new avenues for ecological and demographic studies of other Neotropical carnivores.
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: Infection dynamics in coexisting sexual and asexual host populations: support for the Red Queen hypothesis
The persistence of sexual reproduction is a classic problem in evolutionary biology. The problem stems from the fact that, all else equal, asexual lineages should rapidly replace coexisting sexual individuals due to the cost of producing males in sexual populations. One possible countervailing advantage to sexual reproduction is that, on average, outcrossed offspring are more resistant than common clones to coevolving parasites, as predicted under the Red Queen hypothesis. In the present study, we evaluated the prevalence of infection by a sterilizing trematode (Microphallus sp.) in a natural population of freshwater snails that was composed of both sexual and asexual individuals (Potamopyrgus antipodarum). More specifically, we compared the frequency of infection in sexual and asexual individuals over a five-year period at four sites at a natural glacial lake (Lake Alexandrina, South Island, New Zealand). We found that at most sites and over most years, the sexual population was less infected than the coexisting asexual population. Moreover, the frequency of uninfected sexual females was periodically greater than two times the frequency of uninfected asexual females. These results give clear support for a fluctuating parasite-mediated advantage to sexual reproduction in a natural population.
Data from: Herbivory promotes dental disparification and macroevolutionary dynamics in grunters (Teleostei: Terapontidae), a freshwater adaptive radiation
Trophic shifts into new adaptive zones have played major (although often conflicting) roles in reshaping the evolutionary trajectories of many lineages. We analyze data on diet, tooth, and oral morphology and relate these traits to phenotypic disparification and lineage diversification rates across the ecologically diverse Terapontidae, a family of Australasian fishes. In contrast to carnivores and most omnivores, which have retained relatively simple, ancestral caniniform tooth shapes, herbivorous terapontids appear to have evolved a variety of novel tooth shapes at significantly faster rates to meet the demands of plant-based diets. The evolution of herbivory prompted major disparification, significantly expanding the terapontid adaptive phenotypic continuum into an entirely novel functional morphospace. There was minimal support for our hypothesis of faster overall rates of integrated tooth shape, spacing, and jaw biomechanical evolution in herbivorous terapontids in their entirety, compared with other trophic strategies. There was, however, considerable support for accelerated disparification within a diverse freshwater clade containing a range of specialized freshwater herbivores. While the evolutionary transition to herbivorous diets has played a central role in terapontid phenotypic diversification by pushing herbivores toward novel fitness peaks, there was little support for herbivory driving significantly higher lineage diversification compared with background rates across the family.
Data from: Mosaic patterns of diversification dynamics following the colonization of Melanesian islands
The fate of newly settled dispersers on freshly colonized oceanic islands is a central theme of island biogeography. The emergence of increasingly sophisticated methods of macroevolutionary pattern inference paves the way for a deeper understanding of the mechanisms governing these diversification patterns on lineages following their colonization of oceanic islands. Here we infer a comprehensive molecular phylogeny for Melanesian Exocelina diving beetles. Recent methods in historical biogeography and diversification rate inference were then used to investigate the evolution of these insects in space and time. An Australian origin in the mid-Miocene was followed by independent colonization events towards New Guinea and New Caledonia in the late Miocene. One colonization of New Guinea led to a large radiation of >150 species and 3 independent colonizations of New Caledonia gave rise to about 40 species. The comparably late colonizations of Vanuatu, Hawaii and China left only one or two species in each region. The contrasting diversification trajectories of these insects on Melanesian islands are likely accounted for by island size, age and availability of ecological opportunities during the colonization stage.
Data from: Density dependence, precipitation, and biological control agent herbivory influence landscape-scale dynamics of the invasive Eurasian plant Linaria dalmatica
1. Resource availability and natural enemies are among the most commonly cited mechanisms affecting competitive ability of invasive plants, but their simultaneous effects on plant dynamics are seldom evaluated in the field. Understanding how endogenous and exogenous factors affect invasive plant abundance is essential when evaluating the impact of classical weed biological control agents because misinterpretations of the mechanisms regulating plant demography may bias inference of herbivore impact. 2. In this study we report results from a citizen-science monitoring program initiated to evaluate the effects of the stem–mining weevil Mecinus janthiniformis on the Eurasian invasive weed Dalmatian toadflax Linaria dalmatica. We used a discrete model of population dynamics to evaluate the relative importance of endogenous and exogenous processes affecting changes in ramet density of L. dalmatica at 38 spatially replicated sites in Idaho, USA. 3. Analysis of per capita population growth rates based on ramet density indicated the presence of direct density dependence, which was most likely due to intraspecific competition. Changes in ramet density were not influenced by the abundance of the resident plant community. 4. Precipitation had a strong, positive effect on ramet density of L. dalmatica while the abundance of M. janthiniformis had a weaker, but significant, negative effect after accounting for the density dependence. There was no support for an interactive effect between precipitation and herbivory. 5. Synthesis and applications. Our results indicate that biological control is an important factor affecting weed population growth at the landscape scale, but they also suggest that biological control impact may vary considerably on local infestations due to site-specific variation in rainfall and density-dependent processes. We recommend that invasive plant management strategies integrate precipitation and biological control agent monitoring into their programs to estimate expected biological control efficacy. Alternative control methods should be prioritized in areas where herbivore impact is expected to be low.
Data from: Integrating phylogeography and paleoecology to investigate the origin and dynamics of hybrid zones: insights from two widespread North American firs
Secondary contact between closely related taxa routinely occurs during postglacial migrations. After initial contact, the location of hybrid zones may shift geographically or remain spatially stable over time in response to various selective pressures or neutral processes. Studying the extent and direction of introgression using markers having contrasted levels of gene flow can help unravel the historical dynamics of hybrid zones. Thanks to their contrasted maternal and paternal inheritance, resulting in different levels of gene flow for mitochondrial and chloroplast DNA (mtDNA and cpDNA), the Pinaceae stand out as a relevant biological model for this purpose. The objective of the study was to assess whether the hybrid zone between Abies balsamea and Abies lasiocarpa (two largely distributed Pinaceae) has moved or remained stable over time by analysing the distribution of cytoplasmic DNA variation as well as published palaeobotanical data. Interspecific gene flow was higher for cpDNA than mtDNA markers; hence, the geographic distribution of mitotypes was more congruent with species distributions than chlorotypes. This genetic signature was contrary to expectations under a moving hybrid zone scenario, as well as empirical observations in other conifers. Genetic evidence for this rare instance of stable hybrid zone was corroborated by the colonization chronology derived from published fossil data, indicating that the two fir species initially came into contact in the area corresponding to the current sympatric zone 11 kyr ago. While an explanatory analysis suggested the putative influence of various environmental factors on the relative abundance of cytoplasmic genome combinations, further research appears necessary to assess the role of both demographic history and selective factors in driving the dynamics of hybrid zones.
Data from: Water level fluctuations and metapopulation dynamics as drivers of genetic diversity in populations of three Tanganyikan cichlid fish species
Understanding how genetic variation is generated and maintained in natural populations, and how this process unfolds in a changing environment, remains a central issue in biological research. In this work, we analyzed patterns of genetic diversity from several populations of three cichlid species from Lake Tanganyika in parallel, using the mitochondrial DNA control region. We sampled populations inhabiting the littoral rocky habitats in both very deep, and very shallow areas of the lake. We hypothesized that the former would constitute relatively older, more stable and genetically more diverse populations, because they should have been less severely affected by the well-documented episodes of dramatic water level fluctuations. In agreement with our predictions, populations of all three species sampled in very shallow shorelines showed traces of stronger population growth than populations of the same species inhabiting deep shorelines. However, contrary to our working hypothesis, we found a significant trend towards increased genetic diversity in the younger, demographically less stable populations inhabiting shallow areas, in comparison to the older and more stable populations inhabiting the deep shorelines. We interpret this finding as the result of the establishment of metapopulation dynamics in the former shorelines, by the frequent perturbation and reshuffling of individuals between populations due to the lake level fluctuations. The repeated succession of periods of allopatric separation and secondary contact is likely to have further increased the rapid pace of speciation in lacustrine cichlids.
Data from: Increasing frequency of low summer precipitation synchronizes dynamics and compromises metapopulation stability in the Glanville fritillary butterfly
Climate change is known to shift species' geographical ranges, phenologies and abundances, but less is known about other population dynamic consequences. Here, we analyse spatio-temporal dynamics of the Glanville fritillary butterfly (Melitaea cinxia) in a network of 4000 dry meadows during 21 years. The results demonstrate two strong, related patterns: the amplitude of year-to-year fluctuations in the size of the metapopulation as a whole has increased, though there is no long-term trend in average abundance; and there is a highly significant increase in the level of spatial synchrony in population dynamics. The increased synchrony cannot be explained by increasing within-year spatial correlation in precipitation, the key environmental driver of population change, or in per capita growth rate. On the other hand, the frequency of drought during a critical life-history stage (early larval instars) has increased over the years, which is sufficient to explain the increasing amplitude and the expanding spatial synchrony in metapopulation dynamics. Increased spatial synchrony has the general effect of reducing long-term metapopulation viability even if there is no change in average metapopulation size. This study demonstrates how temporal changes in weather conditions can lead to striking changes in spatio-temporal population dynamics.
Data from: Wear, tear and systematic repair: testing models of growth dynamics in conodonts with high-resolution imaging
Conodont elements are the earliest mineralised vertebrate dental tools and the only ones capable of extensive repair. Two models of conodont growth, as well as the presence of a larval stage, have been hypothesised. We analysed normally and pathologically developed elements to test these hypotheses and identified three ontogenetic stages characterised by different anisometric growth and morphology. The distinction of these stages is independently corroborated by differences in tissue strontium content. The onset of the last stage is marked by the appearance of wear resulting from mechanical food digestion. At least five episodes of damage and repair could be identified in the normally developed specimen. In the pathological element, function was compromised by development of abnormal denticles. This development can be reconstructed as addition of new growth centres out of the main growth axis during an episode of renewed growth. Our findings support the model of periodic retraction of elements and addition of new growth centres. Changes in strontium content coincident with distinct morphology and lack of wear in the early life stage indicate that conodonts might have assumed their mature feeding habit of predators or scavengers after an initial larval stage characterised by a different feeding mode.
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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.