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691 results for “vegetation data”
Data from: Immediate and carry-over effects of insect outbreaks on vegetation growth in West Greenland assessed from cells to satellite
Aim: Tundra ecosystems are highly vulnerable to climate change and climate-growth responses of Arctic shrubs are variable and altered by microsite environmental conditions and biotic factors. With warming and drought during the growing season, insect-driven defoliation is expected to increase in frequency and severity with potential broad-scale impacts on tundra ecosystem functioning. Here we provide the first broad-scale reconstruction of spatiotemporal dynamics of past insect outbreaks by assessing their effects on shrub growth along a typical Greenlandic fjord climate gradient from the inland ice to the sea. Location: Nuuk Fjord (64°30′N/51°23′W) and adjacent areas, West Greenland. Taxa: Great brocade (Eurois occulta L.) and grey willow (Salix glauca L.). Methods: We combined dendro-anatomical and remote sensing analyses. Time series of ring width and wood-anatomical traits were obtained from chronologies of > 40 years established from 153 individuals of S. glauca collected at nine sites. We detected anomalies in satellite-based Normalized Difference Vegetation Index (NDVI) related to defoliation and reconstructed past changes in photosynthetic activity across the region. Results: We identified outbreaks as distinctive years with reduced ring width, cell-wall thickness and vessel size, without being directly related to climate but matching with years of parallel reduction in NDVI. The two subsequent years after the defoliation showed a significant increase in ring width. The reconstructed spatiotemporal dynamics of these events indicate substantial regional variation in outbreak intensity linked to the climate variability across the fjord system. Main conclusions: Our results highlight the ability of S. glauca to cope with severe insect defoliation by changing carbon investment and xylem conductivity leading to high resilience and rapid recovery after the disturbance. Our multi-proxy approach allows us to pin-point biotic drivers of narrow ring formation and to provide new broad-scale insight on the C-budget and vegetation productivity of shrub communities in a widespread arctic ecosystem
Data from: Timing of vegetation sampling does not influence associations between visual obstruction and turkey nest survival in a montane forest
Evaluating relationships between ecological processes that occur concurrently is complicated by the potential for such processes to covary. Ground-nesting birds rely on habitat characteristics that provide concealment from predators; this protection often is provided by vegetation at the nest. Recently, researchers have raised concern that measuring vegetation at nest fate introduces a bias, as vegetation at successful nests is measured later in the growing season. This bias can lead to an erroneous conclusion that plant height is positively associated with nest survival. However, if the features that provide concealment are invariant during the incubation period, no bias should be expected, and the timing of measurement is less influential. We used data collected from 98 nests to evaluate whether there is evidence that such a bias exists in a study of wild turkey (Meleagris gallopavo) nesting in a forest ecosystem. We modelled nest survival as a function of visual obstruction and other covariates of interest. At unsuccessful nests, we collected visual obstruction readings at both the date of nest failure and the projected hatch date and compared survival estimates generated using both sets of vegetation data. In contrast to studies in other systems, we found little evidence that the timing of vegetation sampling influenced conclusions regarding the association between visual obstruction and survival; model selection and estimates of nest survival were similar regardless of when vegetation data were collected. The dominant hiding cover at most of our nests was provided by evergreen shrubs; slow growth of these plants likely prevent appreciable changes in visual obstruction during incubation. When considered with a growing body of literature, our results suggest that the influence of timing of sampling depends on the study system. When designing future studies, investigators should consider the structures that provide nest concealment and whether phenology is confounded with nest survival.
Data from: Does vegetation change over 28 years affect habitat use and reproductive success?
<p>Individuals should prefer and use habitats that confer high fitness, but habitat use is not always adaptive. Vegetation in natural landscapes changes gradually and the ability of species to adaptively adjust their habitat use to long-term changes is largely unstudied. We studied nest patch and territory use over 28 years in Orange-crowned Warblers (Oreothlypis celata) in a system that has undergone natural long-term changes in vegetation. Abundance of maple (Acer grandidentatum), its preferred nesting habitat, has gradually declined from 1987 to 2015. We examined whether habitat use and its fitness consequences changed as the availability of preferred habitat decreased. We used resource selection function models to determine changes over time in the probability of using a nest patch given available patches, and the probability of using a territory given available territories. We estimated nest survival to evaluate changes over time in the fitness consequences of nest patch use. We also compared habitat use (nest patch and territory) and fitness (nest survival) between areas with naturally reduced abundance of maple and experimentally increased abundance of maple (fenced areas). Nest patch use depended on maple abundance and did not change drastically across 28 years, even though the availability of preferred maple patches decreased over time. In contrast, nest survival tended to decrease over time. We did not see differences in nest patch use and nest survival between unfenced and fenced areas, unlike territory use, which increased with the abundance of maple in fenced areas and decreased in unfenced areas. Our study depicts one example of relatively unchanged habitat use in the face of decreased availability of preferred vegetation across years, with a resulting decrease in reproductive success. Investigating changes in habitat use and fitness consequences for animals exposed to long-term habitat change is necessary to understand adaptive behavioral responses. </p>
Data set: Burn severity and soil chemistry are weak drivers of early vegetation succession following a boreal mega-fire in a production forest landscape
<p>Data used in the analyses of the study. Data set on soil chemistry (pH, organic content, nutrient content), plots distance to the fire perimeter, and plant communities (vascular plants and bryophytes) recorded in permanent plots on clearcuts in a burn-severity gradient two and five years following a wildfire. Data collected from a 13000 hectare wildfire that occurred in 2014, in boreal southern Sweden. Calculated trait means from data bases, and plant community data from unburned plots from another study, are are also included here.</p>
The fate of páramo plant assemblages in the sky islands of the northern Andes - Appendix S1. Vegetation and occurrence data used in this study
<p><strong>Aims:</strong> Assessing climate change impacts on biodiversity is a main scientific challenge, especially in the tropics, therefore, we predicted the future of plant species and communities on the unique páramo sky islands. We implemented the <i>Spatially Explicit Species Assemblage Modelling</i> framework, by i) calculating species' maximum dispersal distance, ii) modelling species distributions at present up to 2100, iii) assembling models into communities. Finally, we assessed the vulnerability of sky islands based on richness and composition changes.</p> <p><strong>Location: </strong>Ecuadorian super-páramo (>4200 m)</p> <p><strong>Methods:</strong> Using species trait data, the maximum dispersal distance of 435 species was calculated. Species distribution models (SDM) were fitted to obtain current and future distribution predictions based on dispersal and bioclimatic factors. The final assemblages for present and 2100 were achieved by stacking all probabilistic SDMs and applying the probability ranking rule. The vulnerability of each sky island was evaluated by quantifying richness and composition changes.</p> <p><strong>Results: </strong>Maximum dispersal distances ranged between 0.008-6027 m/year, and across all scenarios, 70% of models showed a net loss in species distribution while 9% of all species were predicted to undergo extinction by 2100. Local richness was estimated to decrease by 56.63% on average, and composition changes in each sky island suggested a mean loss of 64.74% of their original species pool against a 12.97% gain. Finally, 5% of the sky island floras reconverted from high-elevation to low-elevation species. These numbers were usually more important for high-elevation species and the mountains Pichincha, Ilinizas and Antisana.</p> <p><strong>Conclusions:</strong> Our study is methodologically pioneer and provides novel insight on the future of páramo biodiversity. Significant losses in species distribution and changes in community richness and composition suggest drastic impacts and call for further study considering additional factors, such as land-use. Finally, we recommend focusing monitoring and conservation strategies on the northern sky islands in priority.</p>
Data from: Plant community composition steers grassland vegetation via soil legacy effects
<p>Soil legacy effects are commonly highlighted as drivers of plant community dynamics and species co-existence. However, experimental evidence for soil legacy effects of conditioning plant communities on responding plant communities under natural conditions is lacking. We conditioned 192 grassland plots using six different plant communities with different ratios of grasses and forbs and for different durations. Soil microbial legacies were evident for soil fungi, but not for soil bacteria, while soil abiotic parameters did not significantly change in response to conditioning. The soil legacies affected the composition of the succeeding vegetation. Plant communities with different ratios of grasses and forbs left soil legacies that negatively affected succeeding plants of the same functional type. We conclude that fungal-mediated soil legacy effects play a significant role in vegetation assembly of natural plant communities.</p>
Data from: Using a trait-based approach for assessing the vulnerability and resilience of hillslope seep wetland vegetation cover to disturbances in the Tsitsa River catchment, Eastern Cape, South Africa
<p>Hill slope seep wetlands are ecologically and economically important ecosystems as they supply a variety of ecosystem services to society. In South Africa, livestock grazing is recognised as one of the most important disturbance factors changing the structure and function of hill slope seep wetlands. This study sought to investigate the potential effect of livestock grazing on the resilience and vulnerability of hillslope seep wetland vegetation cover using a trait based approach (TBA). Changes in vegetation cover were used as a surrogate for indicating grazing intensity. The degree of human disturbances was assessed using the Anthropogenic Activity Index (AAI). A TBA was developed using seven plant traits, resolved into 27 trait attributes. Based on the developed approach, plant species were grouped into vulnerable and resilient groups in relation to grazing pressure. It was then predicted that species belonging to the vulnerable group would be less dominant at the highly disturbed sites, as well as in the winter season when grazing pressure is at its peak. The approach developed enabled accurate predictions of the responses of hillslope plant species to grazing pressure seasonally, but spatially, only for the summer season. The predicted responses during the winter season across sites did not match the observed results, which could be attributed to the difficulty in species identification and accurate estimation of vegetation cover during winter. Overall, the approach developed here provides a general framework for applying the TBA and can thus be tested and applied elsewhere.</p>
Data from: Changes in levels of enzymes and osmotic adjustment compounds in key species and their relevance to vegetation succession in abandoned croplands of a semiarid sandy region
<p>Reclamation of cropland from grassland is regarded as a main reason for grassland degradation; understanding succession from abandoned cropland to grassland is thus crucial for vegetation restoration in arid and semiarid areas. Soil becomes dry when cropland is reverted to grassland, and enzyme and osmotic adjustment compounds may help plants to adapt to a drying environment. Croplands that were abandoned in various years on the Ordos Plateau in China, were selected for the analysis of the dynamics of enzymes and osmotic adjustment compounds in plant species during vegetation succession. With increasing number of years since abandonment, levels of superoxide dismutase<span> increased</span><span> in </span><i><span><span>Stipa</span></span></i><i><span><span> bungeana</span></span></i><span>, first decreased </span><span>and then increased in </span><i><span><span>Lespedeza</span></span></i><i><span><span> davurica</span></span></i><span> and </span><i><span><span>Artemisia f</span></span></i><i><span><span>rigida</span></span></i><span>, and fluctuated in </span><i><span><span>Heteropappus altaicus</span></span></i><span>. Levels</span> of<span> peroxidase and catalase in the four species fluctuated</span><span>;</span> levels of<span> proline, soluble sugar and soluble protein either</span><i> </i><span>decreas</span><span>ed</span><span> or</span><span> first </span><span>increase</span><span>d</span><span> and</span><span> then</span><span> generally decreased.</span> According to <span>a </span><span>drought resistance</span><span> index</span>, the <span>drought resistance of the </span><span>four </span><span>species</span><span> was </span><span>ranked in descending order as follows</span>: <i><span>S. bungeana </span></i><span>> </span><i><span>A. frigida </span></i><span>> </span><i><span>H. altaicus</span></i> <span>> </span><i><span>L. davurica</span></i>. The drought resistance ability of the different species was<span> closely linked with vegetation succession from communities dominated by annual and biennial species (with main accompanying species of </span><i><span><span>L.</span></span></i><i><span><span> davurica</span></span></i> <span>and</span><i><span><span> H. altaicus</span></span></i><span>) to communities dominated by perennial species (</span><i><span><span>S.</span></span></i><i><span><span> bungeana</span></span></i><span> and </span><i><span><span>A. f</span></span></i><i><span><span>rigida</span></span></i><span>) when soil became dry owing to increasing evapotranspiration after cropland abandonment. </span>The restoration of <i><span>S. bungeana </span></i>steppe after cropland abandonment on the Ordos Plateau<span> is recommended both as high-quality forage and for environmental sustainability</span>.</p>
Data from: Functional responses of aquatic and riparian vegetation to hydrogeomorphic restoration of channelized lowland streams and their valleys
1. Streams and riparian zones are highly heterogeneous ecosystems. Their high biodiversity is promoted by variable flow velocities and water depths, strong hydrological gradients and disturbance regimes. However, human interventions like damming and channelization have degraded these ecosystems worldwide. And, although restoration efforts have increased in the past decades, ecological improvement is lagging. 2. We assessed vegetation development in channelized lowland stream valleys in the Netherlands, combining innovative restoration measures to the stream and stream valleys. This 'stream valley restoration' entailed construction of narrower and shallower channels to increase flow velocities during base discharges, meandering of the watercourse to increase flow and depth heterogeneity and excavation of banks to create wide v-shaped stream valleys. We evaluated the effects on functional aspects of the developing in-stream and riparian vegetation by comparing restored stream reaches to nearby unrestored reaches. 3. The reduced channel dimensions led to higher flow velocities, which, through interaction with meandering, triggered a higher variability in flow and depth. Combined with enlargement of the floodplain, this promoted flooding in stream valleys and created wider environmental gradients. Plant diversity strongly increased in the floodplain area, the land-water interface and the shallow water habitat at the channel margins, but decreased in the central parts of stream channels. There, higher flow velocities led to more typically lotic (running water) in-stream plant communities, indicated by a sharp decrease in floating-leaved species and an increase in trailing species. Riparian vegetation showed a higher beta-diversity across the wider valley slopes of restored reaches, with more wetland species in areas with water tables between 0.0 and -0.6 m, and more upland species as well. 4. Synthesis and applications. This study demonstrates that the combination of strongly reduced channel dimensions, remeandering and widening of riparian zones, is effective in restoring in-stream and riparian habitat heterogeneity. The restoration efforts lead to distinct immediate increases in total and beta-diversity of many typical stream and riparian plant species. Overall, this stresses the importance of applying restoration measures to both streams and stream valleys simultaneously, considering them as a single landscape unit. 27-Nov-2018
Data from: Concordance in wetland physicochemical conditions, vegetation, and surrounding land cover is robust to data extraction approach
Concordance among wetland physicochemical conditions, vegetation, and surrounding land cover may result from the influence of land cover on the sources of plant propagules, on physicochemical conditions, and their subsequent determination of growing conditions. Alternatively, concordance may result if differences in climate, soils, and species pools are spatially confounded with differences in human population density and land conversion. Further, we expect that land cover within catchment boundaries will be more predictive than land cover in symmetrical buffers if runoff is a major pathway. We measured concordance between land cover, wetland vegetation and physicochemical conditions in 48 prairie pothole wetlands, controlling for inter-wetland distance. We contrasted land-cover data collected over a four-year period by multiple extraction approaches including topographically-delineated catchments and nested 30 m to 5,000 m radius buffers. After factoring out inter-wetland distance, physiochemical conditions were significantly concordant with land cover. Vegetation was not significantly concordant with land cover, though it was strongly and significantly concordant with physicochemical conditions. More, concordance was as strong when land cover was extracted from buffers <500 m in radius as from catchments, indicating the mechanism responsible is not topographically constrained. We conclude that local landscape structure does not directly influence wetland vegetation composition, but rather that vegetation depends on physicochemical conditions in the wetland (which are affected by surrounding land cover) and on regional factors such as the vegetation species pool and geographic gradients in climate, soil type, and land use.
Data from: From pristine forests to high-altitude pastures: an ecological approach to prehistoric human impact on vegetation and landscapes in the western Italian Alps
1. This paper addresses the origin and development of the oldest prehistoric pasture in the timberline ecotone known so far in the Alps and its relation to anthropogenic pressure and natural climate change. 2. Paleoecological and geochemical techniques were applied on the Crotte Basse mire stratigraphy (2365 m asl, western Italy) to describe changes in vegetation composition, forest biomass, land use and fertilization between ca. 6400 - 1800 yrs cal BP. 3. Subalpine forests dominated by Pinus cembra occurred at very high-altitude up to ca. 5600 yrs cal BP, when a sharp contraction of woody vegetation took place. This major vegetation shift is matched by increasing charcoal input and markers of pastoral/grazing activities (pollen, dung spores, and forms of phosphorus) in the sediment sequence in this small basin. 4. Major phases of landscape change detected in our multiproxy record chronologically match intervals of cumulative probability density of 14C ages from nearby archaeological sites, suggesting that human activity was the factor leading to massive landscape change from the onset of the Copper Age (ca. 5600 yrs cal BP). The change may have been reinforced by climate variability in the period 5700 - 5300 years cal BP. 5. Sensitivity of woody species to fires was statistically explored (Appendix S3 in Supporting Information), revealing negative reactions of Pinus cembra and Betula to frequent fire episodes and positive reactions of Alnus viridis and Juniperus. Fire episodes do not affect Larix dynamics. 6. Synthesis: Mt. Fallère provides some of the oldest and consistent evidence so far available in the Alps for major anthropogenic pressure at the upper forest limit. As far back as 5600 cal years BP, high-elevation forest ecosystems were permanently disrupted and the alpine pastures were created. Palaeoecological data enable a clear distinction between a random and sporadic use of the alpine space, typical for Mesolithic and Neolithic societies, and an organized seasonal exploitation of natural resources, starting from the Copper Age onwards. The chronological comparison of independent climate proxies, paleoecological information and pollen-based temperature reconstructions sheds light on the relationships between climate and humans since prehistoric times.
Data from: Thresholds and gradients in a semi-arid grassland: long-term grazing treatments induce slow, continuous and reversible vegetation change
1. Temporal changes in semi-arid ecosystems can include transitions between alternative stable states, involving thresholds and multiple domains of attraction, but can also include relatively continuous, symmetric and reversible shifts within a single stable state. Conceptual state-and-transition models (STMs) describe both types of ecosystem dynamics by including state transitions (plant community changes difficult-to-reverse without substantial input or effort) and phase shifts (easily reversible community changes) as consequences of management practices and environmental variability. Grazing management is purported to be the primary driver of state transitions in current STMs for North American grasslands, but there is limited empirical evidence from these grasslands showing that grazing can cause difficult-to-reverse transitions between alternate stable states. 2 .In a northern mixed-grass prairie in Wyoming, USA, we examined plant community responses to (i) long-term (33-year) grazing intensity treatments (none, light, moderate and heavy stocking rates) and (ii) 8 years of light or no grazing in pastures that were grazed heavily for the previous 25 years. 3. Long-term grazing treatments were associated with distinct, but not stable, plant communities. From year 22 to 33, heavier stocking rates decreased cover of dominant C3 grasses and increased cover of the dominant C4 grass Bouteloua gracilis. 4. Reversing stocking rates from heavy to light or no grazing resulted in reversal of changes induced by prior heavy stocking for dominant C3 grasses, but not for B. gracilis. For both groups, rates of change following grazing treatment reversals were consistent with rates of change during the initial years of the experiment (1982–1990). 5. Synthesis and applications. In a semi-arid rangeland with a long evolutionary history of grazing, different long-term grazing intensity treatments caused slow, continuous, and directional changes with important management implications, but did not appear to induce alternative stable states. For this and similar ecosystems, quantifying the time-scales and compositional gradients associated with key phase shifts may be more important than identifying thresholds between alternative stable states.
Data from: Consequences of grazer-induced vegetation transitions on ecosystem carbon storage in the tundra
1. Large herbivores can control plant community composition and, under certain conditions, even induce vegetation shifts to alternative ecosystem states. As different plant assemblages maintain contrasting carbon (C) cycling patterns, herbivores have the potential to alter C sequestration at regional scales. Their influence is of particular interest in the Arctic tundra, where a large share of the world's soil C reservoir is stored. 2. We analysed how grazing mammals influence tundra vegetation and how grazer-induced vegetation shifts affect tundra C stocks, by resampling two sites located along pasture rotation fences in northern Norway. These fences have separated lightly grazed areas from heavily grazed areas (in close proximity to the fences) and moderately grazed areas (further away from the fences) for the past 50 years. 14 years earlier, the lightly and moderately grazed areas were dominated by dwarf shrubs, whereas heavy grazing had promoted the establishment of graminoid-dominated vegetation. Since then, both reindeer densities and temperatures have increased, and more time has passed for transient dynamics to be expressed. We expected that the vegetation and C stocks would have changed under all grazing intensities, but not necessarily in the same way. 3. At the site where relative reindeer numbers and trampling intensity had increased the most, graminoid-dominated vegetation was now also found in the moderately grazed area. At the other site, the dominant vegetation types under all grazing intensities were the same as 14 years earlier. 4. We show that the heavily grazed, graminoid-dominated, areas stored less C aboveground than the lightly grazed, shrub-dominated, areas. Yet, the belowground consequences of grazing-induced grassification varied between the sites: Grazing did not alter organic soil C stocks at the site where both evergreen and deciduous shrubs were abundant in the lightly grazed area, whereas heavy grazing increased organic soil C stocks at the site where the deciduous shrub Betula nana was dominant. 5. Our results indicate that despite the negative impacts of grazers on aboveground C storage, their impact on belowground C may even be positive. We suggest that the site-specific responses of organic soil C stocks to grazing could be explained by the differences in vegetation under light grazing. This would imply that the replacement of deciduous shrubs by graminoids, as a consequence of grazing, could be beneficial for C sequestration in tundra soils.
Data from: High-productivity vegetation is important for lessening bird declines during prolonged drought
1.Locations in which ecological assemblages show high resistance to climate pressures, such as drought, are likely to be important refuges for biota in changing climates. We asked whether environmental characteristics of locations were associated with the capacity of bird assemblages to withstand prolonged drought. 2.We used a multi-species index to quantify trends in bird assemblages during a 13-year drought at >500 locations (>18,000 surveys) in the Murray-Darling Basin, south eastern Australia, using data from the Atlas of Australian Birds. We investigated whether the resistance of bird assemblages was associated with: (1) vegetation structure; (2) vegetation productivity (vegetation greenness); (3) landscape context (patch size, landscape vegetation cover); or (4) physical environment (elevation, terrain, topography, availability of surface water). 3.Vegetation productivity, measured by vegetation greenness (Normalized Difference Vegetation Index), was the only potential predictor with strong evidence of an effect, and was positively associated with the index of drought resistance. There was little evidence that variables characterising landscape context, vegetation structure or the physical environment of sites were associated with drought resistance of bird communities. 4.Synthesis and applications. Bird assemblages in locations with high vegetation greenness are more resistant to severe drought. Prioritizing conservation investments in areas with locally high vegetation productivity is likely to be an effective strategy for increasing the resistance of bird assemblages to extreme drought, especially in areas where mean productivity is relatively low, such as arid and semi-arid regions. Remotely sensed vegetation greenness may be a promising source of information for identifying drought refuges for birds and possibly other biota.
Data from: Natural vegetation benefits synergistic control of the three main insect and pathogen pests of fruit crop in southern Africa
1. Most studies of the potential for natural habitat to improve agricultural productivity have been conducted in transformed, temperate regions, but little is known of the importance of agroecosystem services in biodiverse developing countries. 2. Natural vegetation may promote the density and/or diversity of natural enemies of crop pests, but the strength of the effect varies, and few studies directly measure concurrent impacts on pest density. Considering multiple pest species within the same agroecosystem may help explain why some pests are more affected than others by landscape complexity. Here, we investigated multiple pest species (three species of Tephritidae fruit fly, leaf galling flies and pathogenic fungi Fusarium spp.) and their enemies in cultivated mango Mangifera indica, in north-eastern South Africa. 3. The density of generalist Tephritidae fruit flies increased with distance from natural vegetation during harvesting months, and predation rate of pupae sharply decreased from ~50% at the edge with natural vegetation to 0% at 250 m into the crop. Parasitism rates of the cryptic, gall-forming fly increased with proximity to natural vegetation, but pest density was unrelated to distance from natural vegetation. Incidence of the fungal pathogen disease increased with distance from natural vegetation, possibly due to decreased predation of commensal mites. 4. Although the relationship with distance to natural vegetation was significant for all species considered, the strength of this relationship varied across pest species and type of natural enemy studied, suggesting the benefits of natural vegetation depend on each natural enemy species' ability to disperse into the agricultural environment. 5. Synthesis and applications. Our results suggest that natural vegetation is a net source of natural enemies in a region of South Africa that still contains much of its natural biodiversity. However, the decline in natural enemies, and increase in pests, with distance from natural habitat indicates that this biocontrol is limited by natural enemy dispersal. In landscapes like these that are still dominated by natural habitat, conservation biocontrol can still be improved by management aimed at providing corridors of key plants and habitat elements into the crops, to facilitate natural enemy dispersal.
Data from: Complex genetic effects on early vegetative development shape resource allocation differences between Arabidopsis lyrata populations
Costs of reproduction due to resource allocation trade-offs have long been recognized as key forces in life history evolution, but little is known about their functional or genetic basis. Arabidopsis lyrata, a perennial relative of the annual model plant A. thaliana with a wide climatic distribution, has populations that are strongly diverged in resource allocation. In this study, we evaluated the genetic and functional basis for variation in resource allocation in a reciprocal transplant experiment, using four A. lyrata populations and F2 progeny from a cross between North Carolina (USA) and Norway parents, which had the most divergent resource allocation patterns. Local alleles at quantitative trait loci (QTL) at a North Carolina field site increased reproductive output while reducing vegetative growth. These QTL had little overlap with flowering date QTL. Structural equation models incorporating QTL genotypes and traits indicated that resource allocation differences result primarily from QTL effects on early vegetative growth patterns, with cascading effects on later vegetative and reproductive development. At a Norway field site, North Carolina alleles at some of the same QTL regions reduced survival and reproductive output components, but these effects were not associated with resource allocation trade-offs in the Norway environment. Our results indicate that resource allocation in perennial plants may involve important adaptive mechanisms largely independent of flowering time. Moreover, the contributions of resource allocation QTL to local adaptation appear to result from their effects on developmental timing and its interaction with environmental constraints, and not from simple models of reproductive costs.
Data from: Variability in community productivity: mediating effects of vegetation attributes
1. Plant productivity varies though time in response to environmental fluctuations. Reducing variability in productivity requires an improved understanding of how plant community attributes interact with environmental fluctuations to influence plant growth dynamics. We evaluated links between two community attributes, species diversity and abundance-weighted values of specific leaf area (SLA), and temporal variability in grassland productivity at patch (local) and aggregate (multi-patch) spatial scales. 2. Aggregate communities were created by combining patches of spatially-distinct communities of perennial plant species from grassland biodiversity experiments in Texas, USA. Inter-annual variability in aboveground net primary productivity (ANPP) of aggregate communities was analyzed as a function of two multiplicative components, mean temporal variability in the ANPP of patches and temporal synchrony in ANPP dynamics among patches. We used regression analyses to determine whether temporal variability in aggregate ANPP and its components were correlated with either species diversity or community-weighted SLA over 5 years. 3. Temporal variability in ANPP of aggregate communities was strongly correlated with temporal variability in patch ANPP. Increasing mean SLA reduced ANPP variability of aggregate communities by increasing mean productivity. Increased temporal changes in patch-scale SLA further reduced temporal variability in aggregate ANPP by reducing effects of precipitation fluctuations on productivity. Conversely, increasing species diversity over the narrow range measured increased temporal variability in aggregate ANPP. High diversity was associated with reduced dominance of temporally-stable C4 grasses. 4. Our results implicate means and patch-scale temporal dynamics in community SLA as potential indicators of variability in grassland primary productivity through time.
Data from: Postglacial climate and fire-mediated vegetation change on the western Olympic Peninsula, Washington
The mode and tempo of forest compositional change during periods of rapid climate change, including the potential for the fire regime to produce non-linear relationships between climate and vegetation, is a long-standing theme of forest ecological research. In the old conifer forests of the coastal Pacific Northwest, fire disturbances are sufficiently rare that their relation to climate and their ecological effects are poorly understood. We used a 14,700-year high-resolution sediment record from Yahoo Lake on the Olympic Peninsula to examine vegetation (landscape vegetation from pollen and local vegetation from macrofossils) and fire (landscape fire from total charcoal and local fire from charcoal peaks) in conjunction with independent records of climate. We hypothesized that the successional stage of the local forest will exhibit alternate stable states over a range of fire activity, that species turnover will increase abruptly above a certain level of fire activity and that both responses would be more gradual at the landscape scale than the local scale. Supporting these hypotheses, at the local scale we found strong evidence for alternate stable states of late vs. early successional communities and inertia of species turnover to changing fire activity. At the landscape scale, vegetation responded more gradually to changing fire activity. From 14,700 to 7000 years ago, high landscape vegetation turnover occurred along with high landscape fire activity, especially during the warm summers of the early Holocene. In several instances local species turned over completely following fire events but several centuries after climate change. In contrast, during the last 7000 years the local forest composition was dominated by late-successional species with little species turnover despite periods of moderate fire activity. We suggest that the relatively minor climate fluctuations of the past 7000 years were not sufficient to cause large-scale species turnover after fire. The Yahoo Lake fire and vegetation record of the early Holocene provides a model for dramatic ecosystem change following an anticipated shift to warmer summer temperatures.
Data from: Drivers of vegetative dormancy across herbaceous perennial plant species
Vegetative dormancy, that is the temporary absence of aboveground growth for ≥ 1 year, is paradoxical, because plants cannot photosynthesise or flower during dormant periods. We test ecological and evolutionary hypotheses for its widespread persistence. We show that dormancy has evolved numerous times. Most species displaying dormancy exhibit life‐history costs of sprouting, and of dormancy. Short‐lived and mycoheterotrophic species have higher proportions of dormant plants than long‐lived species and species with other nutritional modes. Foliage loss is associated with higher future dormancy levels, suggesting that carbon limitation promotes dormancy. Maximum dormancy duration is shorter under higher precipitation and at higher latitudes, the latter suggesting an important role for competition or herbivory. Study length affects estimates of some demographic parameters. Our results identify life historical and environmental drivers of dormancy. We also highlight the evolutionary importance of the little understood costs of sprouting and growth, latitudinal stress gradients and mixed nutritional modes.
Data from: Informative plot sizes in presence-absence sampling of forest floor vegetation
1. Plant communities are attracting increased interest in connection with forest and landscape inventories due to society's interest in ecosystem services. However, the acquisition of accurate information about plant communities poses several methodological challenges. Here we investigate the use of presence-absence sampling with the aim to monitor state and change of plant density. We study what plot sizes are informative, i.e. the estimators should have as high precision as possible. 2. Plant occurrences were modeled through different Poisson processes and tests were developed for assessing the plausibility of the model assumptions. Optimum plot sizes were determined by minimizing the variance of the estimators. While state estimators of similar kind as ours have been proposed in previous studies, our tests and change estimation procedures are new. 3. We found that the most informative plot size for state estimation is 1.6 divided by the plant density, i.e. if the true density is 1 plant per square meter the optimum plot size is 1.6 square meters. This is in accordance with previous findings. More importantly, the most informative plot size for change estimation was smaller and depended on the change patterns. We provide theoretical results as well as some empirical results based on data from the Swedish National Forest Inventory. 4. Use of too small or too large plots resulted in poor precision of the density (and density change) estimators. As a consequence, a range of different plot sizes would be required for jointly monitoring both common and rare plants using presence-absence sampling in monitoring programmes.
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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.