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Remote coral reefs are thought to be more resilient to climate change due to their isolation from local stressors like fishing and pollution. We tested this hypothesis by measuring the relationship between local human influence and coral community resilience. Surprisingly, we found no relationship between human influence and resistance to disturbance and some evidence that areas with greater human development may recover from disturbance faster than their more isolated counterparts. Our results suggest remote coral reefs are imperiled by climate change, like so many other geographically isolated ecosystems, and are unlikely to serve as effective biodiversity arks. Only drastic and rapid cuts in greenhouse gas emissions will ensure coral survival. Our results also indicate that some reefs close to large human populations were relatively resilient. Focusing research and conservation resources on these more accessible locations has the potential to provide new insights and maximize conservation outcomes. [ABSTRACT FROM AUTHOR]

The short‐term response of humpback whales to boat approach and remote biopsy sampling was investigated in a breeding ground according to age‐class, sex, female reproductive status, social context, sampling system, habitat, and repeated sampling with more than 20 years of data. In a total of 2,248 observed behavioral responses to biopsy sampling, 58.7% showed no response, 40.7% were considered to be weak or moderate responses, and only 0.5% were considered to be strong. No significant difference was found between the response of calves (young‐of‐the‐year) and that of adults, whereas juveniles responded significantly more strenuously. The response of adult whales was influenced by sex, female reproductive status, and social context. Mothers showed the most frequent response to the boat approach, but the weakest response to the biopsy sampling itself, whereas nonlactating females had the strongest response to biopsy sampling. Males responded less when sampled within a competitive group. Repeated sampling of individual adults resulted in decreasing intensity of responses across years. This comprehensive assessment has implications for management authorities, notably in approving research permits for sampling different age classes on breeding grounds. [ABSTRACT FROM AUTHOR]

Despite the Philippines having one of the widest extents and most diverse seagrasses, there are limited reports on the contribution of seagrass vegetation health to organic carbon (OC). Comparative assessments of OC between conserved and disturbed seagrass meadows in a seascape are also lacking. Conservation programs (e.g., marine protected area [MPA]) contribute to the maintenance of ecosystem health and OC storage in seagrass. However, disturbances may negate the effects of MPAs. Disturbances are often due to coastal development pressures linked to the need for industry, food production, and human settlement. Here, we assessed and compared the aboveground biomass (AGB), belowground biomass (BGB), and OC between conserved and disturbed seagrass meadows, then, tested its correlation with vegetation and water quality variables. The study was conducted in Oyon Bay (northwest Philippines), one of the key seascape MPAs in the Philippines. The bay experienced disturbances from a coal power plant, aquaculture, and human settlements for approximately 30 years. Results showed 7× higher AGB, 11× higher BGB, and 1.7× higher OC in conserved sites. The low biomass and OC values in the disturbed sites were correlated to poor vegetation and water quality conditions (particularly high turbidity [ρ = 0.38], high phosphates [ρ = −0.19], and low dissolved oxygen [ρ = −0.31]). Our study showed the effectiveness of MPAs in maintaining ecosystem health and OC in seagrass, but the magnitude of disturbances lessened the benefits from MPAs. Our results have implications on the over‐ or under‐estimation of carbon sequestration not just in Philippine seagrasses but also in most Southeast Asian countries facing similar coastal development pressures. [ABSTRACT FROM AUTHOR]

Motivation: Rapid climate change is altering plant communities around the globe fundamentally. Despite progress in understanding how plants respond to these climate shifts, accumulating evidence suggests that disturbance could not only modify expected plant responses but, in some cases, have larger impacts on compositional shifts than climate change. Climate‐driven disturbances are becoming increasingly common in many biomes and are key drivers of vegetation dynamics at both species and community levels. Palaeoecological records provide valuable observational windows for elucidating the long‐term impacts of these disturbances on plant dynamics; however, sparse resolution and difficulty in disentangling drivers of change limit our ability to understand the impact of disturbance on plant communities. In this targeted review, we highlight emerging opportunities in palaeoecology to advance our understanding about how disturbance, especially fire, impacts the ecological and evolutionary dynamics of terrestrial plant communities. Location: Global examples, with many from North America. Conclusions: We propose a set of palaeoecological and integrative approaches that could greatly enhance our understanding of how disturbance regimes influence global plant dynamics. Specifically, we identify four future study areas: (1) focus on palaeoecological disturbance proxies beyond fire and leverage multi proxy research to examine the influence of interacting disturbances on plant community dynamics; (2) use advances in disturbance and vegetation reconstructions, including ancient sedimentary DNA, to provide the spatial, temporal and taxonomic resolution needed to resolve the relationship between changing disturbance regimes and corresponding shifts in plant community composition; (3) integrate palaeoecological, archaeological and Indigenous knowledge to disentangle the complex interplay between climate, human land use, fire and vegetation structure; and (4) apply "functional palaeoecology" and the synergy between palaeoecology and genetics to understand how fire disturbance has served as a long‐standing selective agent on plants. These frameworks could increase the resolution of disturbance‐driven plant dynamics, potentially providing valuable information for future management. [ABSTRACT FROM AUTHOR]

Aim: Tropical cyclones are large‐scale disturbances that can shape the structure and dynamics of mangrove forests. Although tropical cyclone activity overlaps extensively with the latitudinal distribution of mangrove forests, the relationships between cyclone intensity and frequency and mangrove forest canopy damage and recovery are not understood at the global scale. Using remote sensing data, we examined how mangrove forest structure, climate and cyclone characteristics influence canopy cover loss and recovery dynamics. Location: Global tropics. Time period: 2000–2020. Major taxa studied: Mangrove trees. Methods: Using two satellite‐derived vegetation indices (the enhanced vegetation index and the normalized difference infrared index) from 86 cyclones affecting 56 mangrove sites across the globe, we quantified mangrove canopy loss in relationship to cyclones. Using linear regression and variance decomposition, we identified and ranked significant predictors of cyclone‐induced canopy loss and recovery. Results: Three‐quarters of the studied cyclone disturbances resulted in canopy damage. Stands exposed to high wind speeds and those close to the cyclone paths were more severely damaged, whereas lower damage magnitudes were found in sites with greater past cyclone frequency. Canopy damage was greater in tall mangrove stands but decreased with higher aboveground biomass. The distance from the cyclone path and maximum wind speed were the most important factors, representing > 50% of the explained variation in cyclone damage. There was considerable variation in canopy damage among cyclones, but rates of recovery were similar across all mangrove sites, with the main predictor of recovery time being the degree of canopy loss. Main conclusions: Our results suggest that the resistance of mangrove canopy cover to cyclone disturbance is variably tuned to the cyclone regime and vegetation characteristics, but resilience is inherent to the magnitude of canopy damage because the rate of forest canopy recovery appears to be consistent globally. [ABSTRACT FROM AUTHOR]

Aims: Spruce beetles (Dendroctonus rufipennis) are causing widespread spruce (Picea spp.) mortality in subalpine forests in western North America. Spruce beetles are changing forest structure and composition by killing a dominant overstory species, but we know little about how the understory community responds to the increase in resource availability brought about by spruce mortality, what mechanisms drive its response, or how its response affects other forest properties and processes. Location: Glacier Lakes Ecosystem Experiments Site, Medicine Bow Mountains, Wyoming, USA. Methods: We measured understory community cover and richness in 75 permanent plots during and 10 years after an epidemic spruce beetle outbreak, and measured trait values for 46 common understory species. We used linear regression to determine how the understory community has changed over time and along a gradient of spruce mortality, and to evaluate the relative support for two mechanisms contributing to species responses. Results: Understory cover nearly doubled between sampling periods and increased the most where spruce mortality was most severe. Understory richness doubled and showed a weak positive trend with spruce mortality. Understory species with the largest increases in cover were the most frequent across the landscape before the disturbance, were the tallest at maturity and had the lowest leaf turgor loss points. Fir seedling density decreased over time, with decreases lessening with increases in understory cover. Changes in spruce seedling density were not predicted by changes in understory cover. Conclusions: Our findings highlight some of the diverse ways in which understory communities can be altered by spruce beetle outbreaks, and how the direction and magnitude of change can depend on the amount of spruce mortality as well as on priority effects and traits of pre-disturbance species. Our findings also highlight how understory community changes can have implications for other forest properties and processes, such as tree regeneration and forest recovery. [ABSTRACT FROM AUTHOR]

Copyright of Biotropica is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In disturbance‐adapted ecosystems, the removal of disturbance can lead to losses of diversity and sometimes irreversible changes in community composition. It is important to identify the thresholds at which these changes can occur, and to understand the reversibility of these shifts. We examined this question in a vernal pool ecosystem that evolved with low to moderate levels of grazing disturbance. In this system, it is not clear whether the negative effects of long‐term grazing exclusion are reversible through grazing reintroduction.We compared adjacent vernal pool wetlands in annual Mediterranean grasslands under three grazing management strategies: continuously grazed (100+ years), long‐term excluded (40+ years) and 2 years of reintroduced grazing. We also asked whether grazing treatments altered pool characteristics that are likely to influence plant community composition, and how these relationships changed with environmental conditions.Reintroducing grazing to vernal pools led to both increased diversity and native cover, but the effects on native cover were more immediate than on diversity. We identified several biotic and abiotic mechanisms related to this pattern, including changes to competitive dynamics that favour small statured native annuals and increases in hoofprint microdepressions that make soil moisture more available to plants.Synthesis and applications. Our results show that reintroduced grazing at moderate stocking rates can have significant effects on plant communities after just 2 years and can increase native cover more quickly than overall diversity. Our findings suggest that the negative effects of long‐term grazing exclusion in vernal pools may be reversible, but that land managers interested in restoring diversity should plan to monitor beyond the first two years of grazing reintroduction. [ABSTRACT FROM AUTHOR]

Disturbances are a key part of ecosystem dynamics at multiple scales. They can maintain ephemeral habitat, alter local and landscape biodiversity, drive carbon balance changes and trigger whole ecosystem regime shifts. Yet, there are few theories and only limited frameworks underlying disturbance ecology by which scientists and practitioners can anticipate the impacts of novel disturbances or changes in disturbance regimes. Much of the challenge in developing and testing theories lies in the diversity of ecosystems and disturbance processes and the general inability to (a) properly replicate studies and (b) compare results across disparate systems, from bacterial communities to boreal forests.General syntheses of disturbance processes have identified key aspects of disturbance impact and response—resource stock change, resource flux change, spatial dynamics and trait diversity—that should apply across systems. Yet, application and testing remain challenging due to a lack of a common set of metrics and baselines for comparisons across systems.Here, I propose a discipline‐wide effort to develop and publish standardized metrics (in addition to study‐specific data) such that the field as a whole can build and test general theory that works across ecological systems. Ten metrics spanning event type, location/design data and biotic composition comprise this suite of 'minimum descriptors' and are directly derived from current disturbance ecology theory. Several examples of cross‐system applicability, from bacterial studies to palaeoecological disturbances, are noted. These are example metrics, intended to open the conversation about the most appropriate and theory‐based lines of commonality across the field, and they may be further refined through cross‐disciplinary conversation.The result of standardizing metrics will be a coordinated dataset that allows for inter‐system testing of theory, meaning disturbance ecology studies can move past disparate, seemingly unique systems with little replication to integrated research. To phrase it in another way, disturbance ecology studies should be planned, in part, to contribute to future quantitative meta‐analyses. If done, we (as a community) will be much better prepared to address the challenges of emerging disturbances, novel ecosystems, and no‐analogue changes in disturbance regimes which are anticipated with climate change and increasing human pressures. [ABSTRACT FROM AUTHOR]

Whilst all ecosystems must obey the second law of thermodynamics, these physical bounds and controls on ecosystem evolution and development are largely ignored across the ecohydrological literature. To unravel the importance of these underlying restraints on ecosystem form and function, and their power to inform our scientific understanding, we have calculated the entropy budget of a range of peat ecosystems. We hypothesize that less disturbed peatlands are 'near equilibrium' with respect to the second law of thermodynamics and thus respond to change by minimizing entropy production. This 'near equilibrium' state is best achieved by limiting evaporative losses. Alternatively, peatlands 'far‐from‐equilibrium' respond to a change in energy inputs by maximizing entropy production which is best achieved by increasing evapotranspiration. To test these alternatives this study examined the energy balance time series from seven peatlands across a disturbance gradient. We estimate the entropy budgets for each and determine how a change in net radiation (ΔRn) was transferred to a change in latent heat flux (ΔλE). The study showed that: (i) The transfer of net radiation to latent heat differed significantly between peatlands. One group transferred up to 64% of the change in net radiation to a change in latent heat flux, while the second transferred as little as 27%. (ii) Sites that transferred the most energy to latent heat flux were those that produced the greatest entropy. The study shows that an ecosystem could be 'near equilibrium' rather than 'far from equilibrium'. [ABSTRACT FROM AUTHOR]

We used real plant data obtained from a water treatment plant in Peninsular Malaysia to develop a model to predict fluoride concentration in treated water. We validated the model with real plant data and demonstrated that the model yields good prediction, with mean absolute percentage error close to 10% or less. The validated model was then used to design an internal model control (IMC) tuned feedback controller, combined with a time‐varying feedforward control approach by exploiting the predictable and repetitive pattern of the inlet water flow rate. Simulation studies using random and real disturbance data show that the proposed control has successfully prevented over fluoridation in treated water. The validated model, due to its simplicity, is suitable for future online implementation. It can also be readily applied to model‐based control approaches (e.g., model predictive control) in future studies. [ABSTRACT FROM AUTHOR]

Fire regimes are shifting under climate change. Decadal‐scale shifts in fire regime can disrupt the biogeochemical cycling of carbon (C), nitrogen (N), and phosphorus (P) within forest ecosystems, but the full extent of these disruptions is unknown. It is also unclear whether these disruptions have consequences for the ecological characteristics (e.g., biomass, abundance, and composition) of microbial and invertebrate communities, which together comprise the majority of terrestrial biodiversity and underpin many ecosystem processes. The theoretical framework of ecological stoichiometry has great potential in this context, but it has rarely been used to develop an integrated understanding of the biogeochemical and ecological effects of altered fire regime across trophic levels. Using one of the world's longest‐running fire experiments, located in Queensland, Australia, we carried out a comprehensive investigation into the stoichiometric consequences of a decadal‐scale divergence in prescribed fire frequency and their links to coinciding changes in various ecological characteristics of forest floor microbial and invertebrate communities. Compared to long‐term fire exclusion, forty‐three years of biennial burning led to significantly N‐depleted and/or P‐enriched stoichiometry in soil, leaf litter, leaf litter–associated microbial biomass, and certain groups of invertebrates, although total invertebrate community stoichiometry was not affected. Microbial biomass was 42% lower in biennially burned soils. Invertebrate community composition differed between fire regime treatments on some sampling dates, but fire regime did not have consistent effects on invertebrate biomass or abundance. Microbial biomass and the abundances of some invertebrate taxa were depressed at particularly low and/or high resource N:P, consistent with a coupling of these variables to the stoichiometric effects of decadal‐scale fire regime. Litter transplants likewise indicated that some invertebrate abundances were sensitive to litter properties over 12 months. Together, our results indicate that long‐term changes in fire regime can decouple the within‐ecosystem cycling of N and P, with N and P cycling growing more and less conservative, respectively, under high‐frequency fire in a way that propagates throughout forest floor food webs. Our study provides new insights into the coupled biogeochemical and ecological responses of forest ecosystems to novel fire regimes and establishes a basis for a stoichiometric framework for fire ecology. [ABSTRACT FROM AUTHOR]

Copyright of Biotropica is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Frameworks exclusively considering functional diversity are gaining popularity, as they complement and extend the information provided by taxonomic diversity metrics, particularly in response to disturbance. Taxonomic diversity should be included in functional diversity frameworks to uncover the functional mechanisms causing species loss following disturbance events. We present and test a predictive framework that considers temporal functional and taxonomic diversity responses along disturbance gradients. Our proposed framework allows us to test different multidimensional metrics of taxonomic diversity that can be directly compared to calculated multidimensional functional diversity metrics. It builds on existing functional diversity–disturbance frameworks both by using a gradient approach and by jointly considering taxonomic and functional diversity. We used previously unpublished stream insect community data collected prior to, and for the two years following, an extreme flood event that occurred in 2013. Using 14 northern Colorado mountain streams, we tested our framework and determined that taxonomic diversity metrics calculated using multidimensional methods resulted in concordance between taxonomic and functional diversity responses. By considering functional and taxonomic diversity together and using a gradient approach, we were able to identify some of the mechanisms driving species losses following this extreme disturbance event. [ABSTRACT FROM AUTHOR]

While many dynamic processes have been proposed to produce diversity differences among communities, most empirical investigations focus on static system attributes. An ideal analysis would consider multiple dynamic processes and their impact on many community members, but such analyses can be logistically daunting. I compared Markov chain models of ecological communities to explore general processes leading to diversity differences of sessile species between coral reefs and rocky intertidal mussel beds. As predicted by diversity theory, high diversity coral reefs had lower species replacement probabilities and higher disturbance rates than did lower diversity mussel beds. Intransitivities in species replacements, recruitment limitation and responses to perturbing species from equilibrium (Jacobian elements) did not differ significantly between systems. Tradeoffs between the displacement risk or displacement ability of a species and either disturbance risk or colonising ability were not apparent. Manipulating the coral reef model to eliminate disturbance or intransitivities caused declines in species diversity, whereas removing recruitment limitation or increasing the probability of interspecific replacement did not. Higher overall disturbance levels can explain part of the diversity difference between systems, but much remained unexplained, indicating that details of the pattern and strengths of species interactions were probably extremely important. [ABSTRACT FROM AUTHOR]

The article presents a paper that studies the impact of river regulation on river margin vegetation in eight boreal rivers in the Northern Hemisphere. Topics discussed include comparison of species diversity per site between free flowing and regulated rivers, river-margin vegetation to different types of regulated water-level regulating region and classification of all plant species on the basis of their dispersal mechanisms.

Repeated moderate severity forest disturbances can cause short‐ and long‐term shifts in ecosystem processes. Prior work has found that stand‐replacing disturbances (e.g., clear‐cutting) increase streamflow in temperate forests, but streamflow responses to repeated moderate severity disturbances are more equivocal. This study examined a moderate disturbance caused by an unexpected population irruption of the invasive insect Lymantria dispar (common name: gypsy moth) in 2015–2017. This irruption resulted in defoliation that was locally severe in some areas but spatially heterogeneous at a regional scale. L. dispar larvae consume leaves during the summer growing season, which effectively reduces tree leaf area and associated evapotranspiration. Our regional approach in Southern New England, USA, used data from 83 US Geological Survey (USGS) stream gages to assess whether changes in growing‐season watershed runoff ratios and instantaneous streamflow characteristics during the 2015–2017 L. dispar irruption were associated with satellite‐derived metrics of changes in forest condition (i.e., defoliation), compared to a 20‐year baseline streamflow period. We found a small, linear increase in growing‐season runoff ratio anomalies that was associated with defoliation intensity. The association between defoliation intensity and runoff ratio anomalies was magnified in less anthropogenically impacted reference watersheds. We also found that defoliation intensity was associated with larger volumes of high and medium instantaneous streamflows compared to baseline mean flow conditions. This study provided important insights into the impacts of moderate disturbance on ecohydrology in mesic temperate forests with a unique methodological approach that assessed the impacts of spatially heterogeneous and repeated moderate disturbance at a regional scale. [ABSTRACT FROM AUTHOR]

Amazonian rainforests, once thought to be pristine wilderness, are increasingly known to have been widely inhabited, modified, and managed prior to European arrival, by human populations with diverse cultural backgrounds. Amazonian Dark Earths (ADEs) are fertile soils found throughout the Amazon Basin, created by pre‐Columbian societies with sedentary habits. Much is known about the chemistry of these soils, yet their zoology has been neglected. Hence, we characterized soil fertility, macroinvertebrate communities, and their activity at nine archeological sites in three Amazonian regions in ADEs and adjacent reference soils under native forest (young and old) and agricultural systems. We found 673 morphospecies and, despite similar richness in ADEs (385 spp.) and reference soils (399 spp.), we identified a tenacious pre‐Columbian footprint, with 49% of morphospecies found exclusively in ADEs. Termite and total macroinvertebrate abundance were higher in reference soils, while soil fertility and macroinvertebrate activity were higher in the ADEs, and associated with larger earthworm quantities and biomass. We show that ADE habitats have a unique pool of species, but that modern land use of ADEs decreases their populations, diversity, and contributions to soil functioning. These findings support the idea that humans created and sustained high‐fertility ecosystems that persist today, altering biodiversity patterns in Amazonia. [ABSTRACT FROM AUTHOR]

This article proposes a distributed model‐free adaptive consensus tracking control (DMFACTC) approach for a class of unknown heterogeneous nonlinear discrete‐time multi‐agent systems (MASs) with sensor saturation and measurement disturbance to perform consensus tracking tasks. Meanwhile, both fixed and switching topologies are considered, where only a subset of agents can acquire the desired trajectory information in each topology. A time‐varying linear data model for each agent is first established by utilizing the dynamic linearization method to formulate this algorithm. Merely, the input data and the saturated output data with measurement disturbance of each agent are applied to construct the DMFACTC algorithm without employing any dynamics model information of MASs. The convergence of the designed scheme is strictly proved. It illustrates that the output saturation and switching topologies do not affect the stability of MASs. Moreover, even if the sensor saturation, measurement disturbance, and switching topologies happen simultaneously, the DMFACTC also guarantees that the tracking errors of MASs converge to a small range around the origin. Furthermore, two numerical simulations and a realistic filling system simulation further verify the correctness and effectiveness of the theoretical results. [ABSTRACT FROM AUTHOR]

Natural disturbances like drought and wildfires are expected to increase in prevalence, so understanding how organisms are affected is a key goal for conservationists and biologists alike. While many studies have illustrated long‐term effects of perturbations on survival and reproduction, little is known of short‐term effects to physiology and sexual signal expression. Ornamental traits have been proposed as reliable indicators of environmental health, yet studies are lacking in the context of natural disturbances. Here we present short‐term (7–65 days) responses of male red‐backed fairywrens Malurus melanocephalus to wildfire near the onset of the typical breeding season. Young males of this species are characterized by plastic expression of sexual plumage phenotypes depending on circulating testosterone and body condition. Using two populations with fairywren captures before and after separate wildfires we illustrate that wildfire suppressed molt into ornamented plumage. Neither baseline plasma corticosterone or furcular fat stores were affected by fire. However, fire seemed to interfere with the termporal increase in plasma testosterone during the pre‐breeding season, leading to a lower proportion of males molting into ornamented plumage. Collectively, these findings suggest that wildfires inhibit or greatly delay acquisition of ornamentation in males through enduring suppression of testosterone circulation. [ABSTRACT FROM AUTHOR]

Different conceptions of disturbance differ in the degree to which they appeal to mechanisms that are general and equivalent, or species‐, functional group‐, or interaction‐specific. Some concepts of disturbance, for example, predict that soil disturbances and herbivory have identical impacts on species richness via identical mechanisms (reduction in biomass and in competition). An alternative hypothesis is that the specific traits of disturbance agents (small mammals) and plants differentially affect the richness or abundance of different plant groups. We tested these hypotheses on a degu (Octodon degus) colony in central Chile. We ask whether native and non‐native forbs respond differently to degu bioturbation on runways versus herbivory on grazing lawns. We ask whether this can explain the increase in non‐native plants on degu colonies. We found that biopedturbation did not explain the locations of non‐native plants. We did not find direct evidence of grazing increasing non‐native herbs either, but a grazing effect appears to be mediated by grass, which is the dominant cover. Further, we provide supplementary evidence to support our interpretation that a key mechanism of non‐native spread is the formation of dry soil conditions on grazing lawns. Thus, ecosystem engineering (alteration of soil qualities) may be an outcome of disturbances, in which each interacts with specific plant traits, to create the observed pattern of non‐native spread in the colony. Based on these results, we propose to extend Jentsch and White (Ecology, 100, 2019, e02734) concept of combined pulse/ disturbance events to the long‐term process duality of ecosystem engineering/ disturbance. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Summary: There is current debate on how soil sample pooling affects the measurement of plant–soil feedbacks. Several studies have suggested that pooling soil samples among experimental units reduces variance and can bias estimates of plant–soil feedbacks. However, it is unclear whether pooling has resulted in systematic mismeasurement of plant–soil feedbacks in the literature. Using data from 71 experiments, we tested whether pairwise plant–soil feedback direction, magnitude and variance differed among soil pooling treatments. We also tested whether pooling has altered our understanding of abiotic and biotic drivers that influence pairwise plant–soil feedbacks. Pooling of soil samples among experimental units was used in 42% of examined experiments. Contrary to predictions, pooling did not affect mean pairwise plant–soil feedback effect size or within‐experiment variance. Accounting for soil sample pooling also did not significantly alter our understanding of the drivers of pairwise plant–soil feedbacks. We conclude that there is no evidence that soil sample pooling systematically biases estimates of plant–soil feedback direction, magnitude, variance or drivers across many studies. Given the debate of whether to pool soil samples, researchers should be aware of potential criticisms and carefully consider how experimental design and soil pooling methods influence interpretation of experiments. [ABSTRACT FROM AUTHOR]

Vast areas of boreal peatlands are impacted by linear disturbances known as seismic lines. Tree removal and ground disturbance alter vegetation communities and are expected to change ecosystem functioning. As boreal landscapes continue to be disturbed by linear disturbances, understanding the magnitude and mechanisms of vegetation and phenology changes is the first step toward predicting carbon cycling changes across broad spatial scales. We investigate seismic line disturbances on peatland plant community composition and phenological patterns using readily available digital photography at a bog and a fen in Alberta, Canada. Our objectives were to: (a) compare the understory peatland vegetation on seismic lines with those in adjacent undisturbed areas using two phenological metrics (green and red chromatic coordinates); (b) evaluate if vegetation greenness is directly related to vegetation community composition, and (c) determine whether plot‐scale greenness predicts plant productivity. We found that areas of peatlands intersected by seismic lines have an earlier seasonal peak (maximum greenness) compared to undisturbed areas, and vegetation communities had a stronger relationship to greenness and gross primary production (GPP) at disturbed areas relative to undisturbed areas. This change in understory vegetation results in greater CO2 uptake in disturbed areas. We demonstrate an easy‐to‐use application of digital photography that successfully quantifies phenological changes in boreal peatland vegetation. This nondestructive method for understanding vegetation phenology eliminated the need for fixed infrastructure and allowed us to expand our sampling capacity and study sites while allowing for repeated measures in the future. Plain Language Summary: Industrial activities for oil and gas mining across boreal North America can result in a vast network of linear disturbances called seismic lines. These are narrow clearings cut across peatlands and forests, resulting in the removal of trees and compaction to the soil, leading to changes in both the vegetation communities and how these ecosystems function. One such impact is how the ground‐layer vegetation communities green up over the course of the growing season and how this affects how productive they are. In this study, we investigated the greenness patterns of vegetation communities at two different peatland types impacted by seismic lines. To do this, we collect photographs using smartphones, alongside vegetation surveys and carbon exchange measurements. We found that these disturbances significantly impact the greenness of these communities, with disturbed areas becoming more productive faster. Using smartphones to collect photographs provided a quick and easy method to collect greenness data without the need for expensive equipment or fixed infrastructure. As boreal peatlands continue to be under threat from increased disturbances, this study provides a first step in understanding how greenness and productivity may change in the future. Key Points: Seismic lines cause a shift in vegetation communities and changes in green leaf phenology and greenness metricsReadily available smartphone photography successfully captured the phenological characteristics of these vegetation typesThe change in vegetation causes greater CO2 uptake in the disturbed areas and greenness metrics were good predictors of these CO2 changes [ABSTRACT FROM AUTHOR]

The effects of timber harvest in the moist coniferous forests of western North America are not well documented for ecologically important arthropods such as moths.We assessed the response of macromoth community structure (abundance, sample size‐corrected estimates of species richness and diversity, and overall community composition) to time since deforestation at 20 previously logged sites (1–95 years post‐harvest), and compared the macromoth communities at these stands to four old growth stands.As stand age increased following timber harvest, the number of macromoths captured in ultraviolet light traps increased and the relative abundance of dietary generalists declined, but sample size‐corrected estimates of species richness and diversity did not vary. Macromoth community composition of the youngest stands (<10 years post‐harvest) differed markedly from each other but converged soon thereafter.Macromoth communities at old growth sites featured higher capture rates, lower dominance by dietary generalists, and higher sample size‐corrected estimates of species richness and diversity than at previously logged sites. Community composition profiles for old growth sites differed from all previously logged sites, but the differences were subtle except in comparison to the youngest logged sites. None of the 188 species we sampled were old growth specialists.Our results reveal dramatic initial impacts of deforestation on macromoth communities in moist coniferous forests of western North America. Such effects are largely reversed within two decades post‐harvest but some effects persist for at least 95‐years following logging. [ABSTRACT FROM AUTHOR]

As anthropogenic disturbance continues to encroach on natural areas, it is imperative to establish how this disturbance affects species assemblages. Yellowjackets are important predators of a wide range of arthropods, acting as natural population control in many ecosystems. This study seeks to explore how Vespinae community structure shifts with increasing land development in a temperate North American environment.Yellowjackets were sampled from May to September 2019 using heptyl butyrate and acetic acid plus isobutanol traps. Sampling sites represented a gradient of developed landscapes, from fully forested to entirely developed. Seven species from the genera Dolichovespula and Vespula were trapped during the study.Yellowjacket community structure was found to be significantly affected by the amount of land development. These results were driven by the replacement of Vespula consobrina with Vespula germanica in urban landscapes. A high level of development, greater than 75%, reduced species abundance relative to the fully forested landscapes, primarily due to the loss of Vespula pensylvanica and V. consobrina.Our results highlight that the replacement of forested areas with urban development causes a shift in yellowjacket community composition, favouring generalist scavengers (e.g. V. germanica) and threatening the abundance of forest specialists such as V. consobrina. [ABSTRACT FROM AUTHOR]

Reef building corals are generally believed to require clear, nutrient-poor water. Yet, paradoxically, coral reefs are among the most productive marine ecosystems in the world. This paradox is commonly explained by the coral’s ability to utilize a number of food resources, including zooplankton, phytoplankton, dissolved organic matter and photosynthetic products derived from their endosymbiotic algae, the zooxanthellae. Sedimentation is a known stressor for corals, inhibiting most feeding modes in various ways. However, evidence for enhanced sediment deposition on certain corals, induced by their morphologies, as well as for sediment ingestion by some corals, has led us to examine the use of sediment as a possible source of food for corals in addition to the other, known food sources. Our experiments with fluorescently labelled sediment show transfer of labelled organic matter from the sediment into the cells of the solitary coral Fungia horrida Dana 1846. The results provide the first direct evidence for the ability of a coral to digest the sediment’s organic fraction. These results may indicate a positive role of sediment, which up until now was considered to have only deleterious effects on corals. [ABSTRACT FROM AUTHOR]

We studied food webs comprising fish, macroinvertebrates, and algae (identified to species or morphospecies) in small streams using a consistent methodology at the same spatial and temporal scales. Our aim was to test a priori hypotheses derived from dynamic-demographic and energetics models concerning the effects of disturbance and resource availability on food-web attributes. The regime of bed disturbance affecting the organisms in the webs was measured in 10 streams. We also derived measures of the supply of resources for animals in the webs in terms of algal primary productivity and detritus standing crop. Both web size and number of links per species were significantly negatively related to mean intensity of bed disturbance. Mean chain length had a significant positive relationship with algal primary productivity but not disturbance. No food-web attribute was related to detritus standing crop. [ABSTRACT FROM AUTHOR]

Questions: Agricultural intensification has led to the decline of biodiverse meadows and other semi‐natural grasslands. Road verges offer potential alternative habitats for meadow species, but they may not be suitable for all meadow species due to different soil properties, frequent disturbances, pollution or suboptimal management. Are their communities of vascular plants and bryophytes similar or dissimilar to those in mown or grazed meadows? What kind of species are associated with road verges, mown meadows or grazed meadows? How do the habitat types differ in their soil conditions and disturbance intensity? Location: The study was conducted at 36 sites in central Finland. Methods: We compared the vascular plant and bryophyte flora and the habitat characteristics of road verges, mown meadows and grazed meadows. Results: The community composition of both vascular plants and bryophytes differed among the habitat types. Many species occurred in all three habitat types, but several meadow specialists were absent or less frequent in the road verges. In contrast, road verges hosted more forest species and ruderal species, especially bryophytes. Road verges differed from meadows in their soil conditions. Conclusions: We conclude that although road verges may host some species typical to meadows, their value as alternative habitats could be increased by improved soil preparation and vegetation management. Meanwhile, the continued decline of quality habitats for meadow species underscores the need to maintain, increase and improve meadow management. [ABSTRACT FROM AUTHOR]

Ecological stability refers to a family of concepts used to describe how systems of interacting species vary through time and respond to disturbances. Because observed ecological stability depends on sampling scales and environmental context, it is notoriously difficult to compare measurements across sites and systems. Here, we apply stochastic dynamical systems theory to derive general statistical scaling relationships across time, space, and ecological level of organisation for three fundamental stability aspects: resilience, resistance, and invariance. These relationships can be calibrated using random or representative samples measured at individual scales, and projected to predict average stability at other scales across a wide range of contexts. Moreover deviations between observed vs. extrapolated scaling relationships can reveal information about unobserved heterogeneity across time, space, or species. We anticipate that these methods will be useful for cross‐study synthesis of stability data, extrapolating measurements to unobserved scales, and identifying underlying causes and consequences of heterogeneity. [ABSTRACT FROM AUTHOR]

Stress comprises three sequential stages: the event (stressor), which leads to an initial effect on a focal organism (stress), followed by the organism's ultimate response (recovery or not). Using this framework, we test how the duration and timing of a stressor individually and interactively affect the initial and asymptotic organism outcomes. We applied either long or short water restrictions either early or later in the life of Lepidium sativum. While several of these water restriction treatments caused a noticeable initial effect, all were able to recover fully, except for those exposed to a long early water restriction. While long early stressors led to decreased height, a growth model revealed that both long and short early stressors changed the rate of growth and prolonged the inflection point, findings that would have been missed had effect and response not been analyzed separately. Both the stressor and the magnitude of the initial effect in part explained the change in the growth model parameter estimates. Overall, timing, duration, and, more importantly, the interaction of these two temporal aspects of stress significantly affects an organism's initial response to a stressor and its ability to ultimately recover from stress. Our findings highlight the importance of explicitly studying the interactions of stressor aspects and of examining the immediate stress effects, as well as long‐term responses. [ABSTRACT FROM AUTHOR]

Explaining spatiotemporal variability in metacommunities is challenging because conducting empirical studies that link mechanisms across scales is difficult. We developed a stochastic model of epilithic algal succession in streams to better understand the underlying interactions that drive patch dynamics at three levels of spatial hierarchy: patch, channel habitat, and reach. The state of an algal patch is specified by one of nine community types, which are defined by growth form. Ninety‐two empirical data sets of epilithic succession were used to estimate Markov transition probabilities among patch types as functions of inputs for light, nutrients, and current. Two additional probability matrices determine the effects of herbivory and disturbance based on user inputs. Testing model predictions of patch composition against independent empirical data indicated good correspondence based on resemblance metrics. Early in succession, most patches were occupied by prostrate and erect diatoms. These persisted under low light and nutrient conditions. Motile and stalked diatom patches characterized later stages when resources were moderate. Succession proceeded to mostly filamentous green algal patches under high resource levels. Sensitivity simulations indicated light most affected succession. Herbivory and disturbance increased the probability of prostrate diatom patches. We then used the model to examine how changes in abiotic and biotic parameters affect patch dynamics at different scales. Changes in nutrients or light affected patch diversity differently at the habitat vs. reach scale. Interactions with local resource levels within a channel habitat determined its alpha diversity. The proportion of channel habitat types within a reach, and their collective response to changes, determined beta diversity. Patch diversity within channel habitats generated by herbivory followed the predation hypothesis only when nutrients were low. At the reach scale, herbivory always increased patch similarity among channel habitats, lowering beta diversity. Diversity within channel habitats followed the intermediate disturbance hypothesis for a variety of habitats. Effects of disturbance on beta diversity at the reach scale depended on channel habitat heterogeneity. The stability of patches at the reach scale was highest when disturbance created high patch diversity, supporting the insurance hypothesis. The ideas generated can improve stream bioassessment methods and provide insight into mechanisms underlying patch dynamics in other ecosystems. [ABSTRACT FROM AUTHOR]

Questions: The effects of agriculture on forest biodiversity and ecosystem properties can persist decades or centuries after abandonment. Many Pacific island nations are experiencing declines in traditional agriculture. Seed dispersal and seedling recruitment are critical to forest regeneration, and this is particularly relevant for Polynesia where native seed disperser diversity is low and species have been extirpated to crisis levels. In this study we asked: are secondary lowland tropical forests converging to mature forest, and are there seedling recruitment and survival differences between forest types? Location: The Polynesian island of Tutuila, American Samoa, where traditional agriculture has been on the decline since the 1940s and secondary forests comprise 70% of all forest area. Methods: We surveyed 34 vegetation plots (containing 2,232 adult trees and 6,579 tree seedlings) across mature forest and >50 years old secondary lowland rain forest. We quantitatively compared forest diversity, structure and the 3-year seedling regeneration dynamics of the tree community. Results: Although species richness and stem densities were similar between mature and secondary forest, most diversity and structure parameters remained distinguishable between the two forest types. Basal area remained significantly higher in mature forest; the diagnostic tree species of mature and secondary forest differed; and community composition (as indicated by NMDS) remained significantly different. However, seedling survivorship did not differ between forest types and seedling recruitment patterns indicated that there remained a suite of effective seed dispersers on Tutuila. Conclusions: We conclude that (a) community differences between mature and secondary lowland rainforest were driven by the abundance of diagnostic species rather than exclusion of species from a forest type, and (b) there was no evidence of biophysical or ecological barriers to forest recovery of lowland secondary rain forest, or its convergence towards mature lowland rain forest. Nevertheless, more than 50 years after agricultural abandonment, secondary forest remains distinct from mature forest, highlighting that land use legacies are long-term drivers of forest composition and successional trajectory in post-agricultural landscapes of Polynesia. [ABSTRACT FROM AUTHOR]

Questions: Cold temperatures and freezing may hinder the process of forest expansion in moist climate regions, as predicted by the frost hypothesis. We examined the role of frost on the survival and regrowth of tree saplings under field conditions of open grasslands. Location: Cambará do Sul, Rio Grande do Sul. Methods: We established a field experiment protecting one of two groups of saplings of forest species from frost in grassland areas during the winter. We monitored 672 saplings from a total of seven species for 56 days. Saplings were brought back to the laboratory to evaluate regrowth rate and height. Survival curves of the two groups were compared using a Kaplan–Meier estimator. Correlation analysis was undertaken to estimate the relationship between survival and regrowth rate and a variance analysis was used to compare plant height between both groups. Results: Species respond distinctly to frost incidence, with some not being affected by frost (two gymnosperms and Myrcianthes pungens). Most protected saplings had a higher above-ground survival rate than unprotected ones (96.4% and 73.2%, respectively). Moreover, saplings that were damaged by frost showed differences in regrowth and height according to species identity, notwithstanding the fact that those from protected plots showed higher regrowth and height (88% and 25.65 cm compared to 68% and 17.15 cm). Conclusions: Our results showed clear negative effects of frost on the survival rate of aerial parts of saplings during the winter and the regeneration of damaged plants. Species-specific traits can offer frost resistance; however, together with other disturbances, frost may hinder the establishment of forest trees over grassland areas where frost events are common during the winter. [ABSTRACT FROM AUTHOR]

Ecosystems can respond in a variety of ways to the same agent of disturbance. In some contexts, fire causes large and long‐lasting changes to ecological communities. In others, fire has a limited or short‐lived impact on assemblages of animals and plants. Understanding why this occurs is critical if we are to manage these kinds of disturbances across the globe. A recent synthesis proposed that these seemingly idiosyncratic responses to fire can be understood in the context of habitat openness pre‐disturbance. Assemblages in open habitats should respond less to a single fire event that those in closed habitats. We provide a test of this hypothesis by examining the response of ant (Hymenoptera: Formicidae) communities to large‐scale fire events in three habitats of different natural canopy openness on the Peloponnese peninsula in Greece. We also test the hypothesis that assemblage responses to fire are trait dependent. Fire simplifies the physical structure of the environment, increases insolation, and limits opportunities for ants to exploit herbivorous feeding strategies. Consequently, we predict that ants will face a strong environmental filter between unburnt and recently burnt plots, which will be reflected in their functional morphology. Our analysis shows that burnt plots have more individual ants, more species and an almost complete compositional change relative to unburnt plots. These changes do not depend on initial canopy openness. Rather, we suggest that openness must be interpreted relative to the study taxon; for ants, openness should be measured closer to the ground level. In our study, ground‐level openness does not vary across the plots, which may explain the results. Furthermore, ants in burnt plots are significantly larger, have relatively longer legs, relatively longer mandibles, and more elongate heads. This morphotype fits with our prediction of ants that can move and feed successfully in the burnt micro‐landscape. Ultimately, more work is needed to fully explore the relationship between habitat openness and the response to fire. Our results showing a filtered set of ant morphologies in burnt environments suggest that ant traits may offer a further way forward to understand the faunal response to fire and disturbance in general. [ABSTRACT FROM AUTHOR]

Although most lotic ecosystems experience frequent and sometimes large disturbances, opportunities are uncommon to study primary succession in streams. Exceptions include new stream channels arising from events such as glacial retreat, volcanism, and catastrophic landslides. In 1980, the eruption and massive landslide at Mount St. Helens (WA, U.S.A.) created an entire landscape with five new catchments undergoing primary succession. We asked if riparian and lotic assemblages at early successional stages (36 years after the eruption) showed predictable change along longitudinal gradients within catchments, and whether assemblages were similar among five replicate catchments.In July 2016, we collected environmental data and characterised riparian, algal, and benthic macroinvertebrate assemblages at 21 stream reaches distributed within and among five neighbouring catchments. We evaluated patterns of richness, abundance, biomass, multivariate taxonomic community structure, and functional traits both longitudinally and among catchments.We found minimal evidence that longitudinal gradients had developed within catchments at 36 years post‐eruption. Increases in diatom and macroinvertebrate richness with downstream distance were the only biological responses with longitudinal trends. Conversely, we documented substantial variation in community structure of riparian plants, soft‐bodied algae, diatoms, and macroinvertebrates at the among‐catchment scale. Among‐catchment differences consistently separated two eastern catchments from three western catchments, and these two groups also differed in stream water chemistry, water temperature, and geomorphology.Overall, we documented greater diversity in the young catchments than predicted by ecologists in the years immediately following the eruption, yet functional traits indicate that these catchments are still in relatively early stages of succession. Variation at the among‐catchment scale is likely to be driven in part by hydrological source variation, with the two eastern catchments showing environmental signatures associated with glacial ice‐melt and the three western catchments probably fed primarily by springs from groundwater aquifers. Contemporary flow disturbance regimes also varied among catchments and successional trajectories were probably reset repeatedly in streams experiencing more frequent disturbance.Similar to new stream channels formed following glacial retreat, our results support a tolerance model of succession in streams. However, contrasting abiotic templates among Mount St. Helens catchments appear to be driving different successional trajectories of riparian plant, algal, and macroinvertebrate assemblages among neighbouring small catchments sharing the same catastrophic disturbance history. [ABSTRACT FROM AUTHOR]

Aim: Climate‐induced range expansion ultimately implies recruitment at sites that were previously unoccupied by a species (i.e. colonization events). Using evidence on abiotic conditions and biotic interactions at these migration sites, we aimed to identify migration pathways from northern temperate to boreal forests for species showing northward range expansion. Location: Quebec, Canada. Taxon: Trees of northern temperate/boreal forests. Methods: Using past (1970–1977) and recently updated (2003–2015) forest inventories across 761,100 km2, we first quantified latitudinal shifts for saplings of eight tree species and investigated colonization events at migration sites. We used field evidence and a consensus modelling approach to determine environmental suitability and identify edaphic, climatic and disturbance conditions, as well as species co‐occurrence patterns, characterizing recent colonization events. The results were interpreted in relation to novel species associations facilitating species migration in unsuitable landscapes. Results: All species showed northward latitudinal shifts driven by increased recruitment and colonization northward. Colonization events occurred largely at historically unsuitable sites. Migration sites showed a shift towards humus types characteristic of the boreal forest and not typically found in the core range of most temperate species. Climatic conditions at migration sites were initially colder than at occupied sites, but warming suggests recent climatic suitability. A decrease in conifer basal area at migration sites following disturbances reduced priority effects that possibly constrained deciduous species establishment. Co‐occurrence patterns pointed to deciduous species tolerant of boreal edaphic conditions, leading the way for other temperate species. Main conclusions: Temperate tree species can recruit into sites typical of boreal forests, even under environmentally challenging conditions. Warming and disturbances open up the way for some novel species associations that in turn have the potential to facilitate the recruitment of temperate species into the boreal forest, revealing migration pathways. [ABSTRACT FROM AUTHOR]

Questions: Which environmental factors influence fine‐grain beta diversity of vegetation and do they vary among taxonomic groups? Location: Palaearctic biogeographic realm. Methods: We extracted 4,654 nested‐plot series with at least four different grain sizes between 0.0001 m² and 1,024 m² from the GrassPlot database, covering a wide range of different grassland and other open habitat types. We derived extensive environmental and structural information for these series. For each series and four taxonomic groups (vascular plants, bryophytes, lichens, all), we calculated the slope parameter (z‐value) of the power law species–area relationship (SAR), as a beta diversity measure. We tested whether z‐values differed among taxonomic groups and with respect to biogeographic gradients (latitude, elevation, macroclimate), ecological (site) characteristics (several stress–productivity, disturbance and heterogeneity measures, including land use) and alpha diversity (c‐value of the power law SAR). Results: Mean z‐values were highest for lichens, intermediate for vascular plants and lowest for bryophytes. Bivariate regressions of z‐values against environmental variables had rather low predictive power (mean R² = 0.07 for vascular plants, less for other taxa). For vascular plants, the strongest predictors of z‐values were herb layer cover (negative), elevation (positive), rock and stone cover (positive) and the c‐value (U‐shaped). All tested metrics related to land use (fertilization, livestock grazing, mowing, burning, decrease in naturalness) led to a decrease in z‐values. Other predictors had little or no impact on z‐values. The patterns for bryophytes, lichens and all taxa combined were similar but weaker than those for vascular plants. Conclusions: We conclude that productivity has negative and heterogeneity positive effects on z‐values, while the effect of disturbance varies depending on type and intensity. These patterns and the differences among taxonomic groups can be explained via the effects of these drivers on the mean occupancy of species, which is mathematically linked to beta diversity.We analysed fine‐grain beta diversity of grasslands and other open habitats in the Palaearctic using 4,654 nested‐plot series and the z‐values of power‐law species–area relationships. Mean z‐values were highest for lichens, intermediate for vascular plants and lowest for bryophytes. The strongest environmental predictors of z‐values were herb layer cover (negative), elevation (positive), rock and stone cover (positive) and the c‐value (U‐shaped). In a conceptual figure, we summarize the resulting hypotheses how different predictors could influence z‐values via mean occupancy. [ABSTRACT FROM AUTHOR]

The Balbina hydropower dam in the Central Amazon basin, established in the Uatumã River in the 1980s, is emblematic for its socio‐environmental disaster. Its environmental impacts go far beyond the reservoir and dam, however, affecting the floodplain forests (igapó) in the downstream area (dam shadow), which have been assessed using a transdisciplinary research approach, synthesized in this review.Floodplain tree species are adapted to a regular and predictable flood pulse, with high‐ and low‐water periods occurring during the year. This was severely affected by the operation of the Balbina dam, which caused the suppression of both the aquatic phase at higher floodplain elevations and the terrestrial phase at lower floodplain elevations (termed the 'sandwich effect').During the period of construction and reservoir fill, large‐scale mortality already occurred in the floodplains of the dam shadow as a result of reduced stream flow, in synergy with severe drought conditions induced by El Niño events, causing hydraulic failure and making floodplains vulnerable to wildfires.During the operational period of the dam, permanent flooding conditions at low topographical elevations resulted in massive tree mortality. So far, 12% of the igapó forests have died along a downstream river stretch of more than 125 km. As a result of flood suppression at the highest elevations, an encroachment of secondary tree species from upland (terra firme) forests occurred.More than 35 years after the implementation of the Balbina dam, the downstream impacts caused massive losses of macrohabitats, ecosystem services, and diversity of flood‐adapted tree species, probably cascading down to the entire food web, which must be considered in conservation management.These findings are discussed critically, emphasizing the urgent need for the Brazilian environmental regulatory agencies to incorporate downstream impacts in the environmental assessments of several dam projects planned for the Amazon region. [ABSTRACT FROM AUTHOR]

This paper describes differences in canopy arthropod community structure, major cation content, and calculated nutrient consumption between clearcut and undisturbed hardwood forest watersheds at Coweeta Hydrologic Laboratory, North Carolina, USA, during the first two growing seasons following cutting. Although canopy arthropod biomass was about 0.08% of foliage biomass on both watersheds, aphid mass increased 23-fold and ant mass increased 6-fold per unit foliage mass following cutting. These groups in general had lower nutrient concentrations than did chewing herbivores and predators. Arthropod K concentrations were 33% lower on the clearcut; Na, K, and Mg concentrations were 20%-50% higher in 1978 than in 1977. Arthropod Mg and Ca concentrations, but not Na, and K, were reduced significantly more by the greater effect of drought on the clearcut watershed. Consumption estimates based in part on consumption rates reported by others indicated increased nutrient translocation from foliage via arthropods following cutting. These data indicated that canopy arthropod responses in nutrient availability following disturbance could have increased nutrient cycling rates and contributed to nutrient retention by the recovering ecosystem. [ABSTRACT FROM AUTHOR]

Anthropogenic impacts in estuarine systems can influence marine mammal habitat use, population dynamics, fitness, and mortality events. The objective was to examine habitat use among the resident common bottlenose dolphin (Tursiops truncatus) population inhabiting the Indian River Lagoon, Florida, and the influences of variation in environmental factors and prey availability in 2003–2015. We utilized photo‐identification surveys, stratified random samples of prey, and environmental variables collected monthly. Kernel density estimation was used to determine the magnitude‐per‐unit area of dolphins across the IRL by wet and dry seasons each year, the values were used as a response variable in classification and regression tree analyses with fish community and environmental variables as predictors. Spatial patterns in dolphin density in the IRL were associated with salinity and dissolved oxygen levels, which are in part associated with freshwater discharges of nutrient and algae laden waters from the region's storm water management system. These findings isolate locations of concern for management of dolphin habitat, and anthropogenic drivers of dolphin distributions requiring further research. [ABSTRACT FROM AUTHOR]

Groundwater fluctuation follows the rainfall regime and is a natural source of disturbance by limiting the soil volume available for ant nesting. However, in areas with shallow water‐table unpredicted floods are more frequent, which may also affect the distribution of litter ant species. Here, we evaluated the behavioural responses and diversity changes of litter‐dwelling ants related to groundwater level fluctuation in the central Amazon tropical rainforest.The natural occurrence of vertically stratified litter (above the ground level) accumulated at the base of stemless palms was a control sample in a series of paired samples. We used baits to measure ant activity and Winkler extractors to measure ant diversity in 10 riparian plots during the rainy (shallow water‐table) and dry (deep water‐table) season. We also added processed litter to count the number of new colonies found in both habitats.We found fewer ant species and less occurrence during the rainy season. The assemblage composition was more heterogeneous during rainy season compared to same locations during dry season. However, ant activity such as recruitment and investment in resource monopolization showed an opposite pattern. The investments in reproduction followed ant recruitment to baits, with more colonies found in the leaf‐litter during the dry season. All changes were strongly decreased or absent from the control locations.Our results suggest that unpredicted floods mediated by water‐table fluctuation may act as a disturbance to most ant litter species but may favour resource monopolization and litter colonization. [ABSTRACT FROM AUTHOR]

Catchments in the Luquillo Experimental Forest (LEF) of Puerto Rico are warm, wet and tropical with steep elevational relief creating gradients in temperature and rainfall. Long‐term objectives of research at the site are to understand how changing climate and disturbance regimes alter hydrological and biogeochemical processes in the montane tropics and to provide information critical for managing and conserving tropical forest ecosystems globally. Measurements of hydrology and meteorology span decades, and currently include temperature, humidity, precipitation, cloud base level, throughfall, groundwater table elevation and stream discharge. The chemistry of rain, throughfall, and streams is measured weekly and lysimeters and wells are sampled monthly to quarterly. Multiple data sets document the effects of major hurricanes including Hugo (1989), Georges (1998) and Maria (2017) on vegetation, biota and catchment biogeochemistry and provide some of the longest available records of biogeochemical fluxes in tropical forests. Here we present an overview of the findings and the data sets that have been generated from the LEF, highlighting their importance for understanding montane tropical watersheds in the context of disturbance and global environmental change. [ABSTRACT FROM AUTHOR]

In the context of widespread ecological changes, land managers and policymakers confront the need to prioritize ecosystem restoration and fuel management activities across large areas to sustain ecosystem services. Reference conditions inform prioritization efforts by providing a baseline from which to measure where and how vegetation and fuels have changed, but until recently the USA lacked a complete set of reference conditions. We describe the ongoing development of a comprehensive set of vegetation reference conditions based on over 900 quantitative vegetation dynamic models and accompanying description documents for terrestrial ecosystems in the USA. These models and description documents, collaboratively developed by more than 800 experts around the country through the interagency LANDFIRE Program, synthesize fundamental ecological information about ecosystem dynamics, structure, composition, and disturbance regimes before European‐American settlement. These products establish the first comprehensive national baseline for measuring vegetation change in the USA, providing land managers and policymakers with a tool to support vegetation restoration and fuel management activities at regional to national scales. Users have applied these products to support a variety of land management needs including exploring ecosystem dynamics, assessing current and desired conditions, and simulating the effects of management actions. In an era of rapid ecological change, these products provide land managers with an adaptable tool for understanding ecosystems and predicting possible future conditions. [ABSTRACT FROM AUTHOR]

Biodiversity monitoring is recognised as a key action for ecologically sustainable land use, but there are few examples of landscape programmes. We outline the first five years of biodiversity monitoring focusing on insectivorous bats in low rainfall, multiple‐use forests and woodlands of the Pilliga, Australia. Using ultrasonic sampling over multiple nights, both on‐ and off‐tracks, we identify annual trends in bat activity and occupancy and environmental covariates. Trends differed depending on whether occupancy or bat activity was the response variable. Site occupancy was almost 100% and remained stable and/or did not decline for most species nor diversity over the monitoring period, suggesting little variation in bat populations. In comparison, total activity was initially very high (567 passes night−1 on‐track) and then declined by up to 40% in the following three years, but then fully recovered in the fifth year. This general pattern was evident both on‐ and off‐tracks for most taxa, though activity was three times greater on‐ than off‐track, highlighting the importance of these distinct habitat features for bats. Multivariate state‐space (MARSS) models predicted, unexpectedly, that high winter rainfall prior to our surveys was negatively related to activity for many taxa. In contrast, disturbance from timber harvesting or fire had weak or no identifiable effects on trends in activity for most taxa. One exception was Chalinolobus picatus (threatened), whose occupancy off‐tracks was negatively related to the extent of recent (<5 years) fire and to harvesting, though at the landscape scale, occupancy remained stable. This result, together with patterns for other bat taxa, suggests that disturbance effects were short‐lived/dispersed and/or environmental mitigations were effective at maintaining bat populations at a landscape level. Annual monitoring highlighted annual variation in activity and its implications when setting a baseline for monitoring. We also discuss modifications to future monitoring effort, based on the existing five years of data. [ABSTRACT FROM AUTHOR]

Large wood drives physical and ecological processes in river systems, but the relative roles of continuous individual tree mortality versus episodes of mass mortality in wood recruitment are not well understood. Here, the 2016 Chimney Tops 2 wildfire, a rare severe wildfire in the eastern United States, was used as a case study for examining the role of mass tree mortality in wood loads of streams in Great Smoky Mountains National Park (GSMNP), Tennessee. Wood surveys were conducted on four reaches in two drainage systems affected by the fire to ascertain the total frequency and volume of burned and unburned wood pieces and jams. Relative to unburned wood, the Chimney Tops 2 fire resulted in a major influx of burned wood to the study reaches, with large percentages of individual pieces (average of 47% by frequency, 48% by volume) and jams (average of 72% by frequency, 93% by volume) exhibiting burn marks. Burned wood pieces had a larger diameter than unburned pieces (p =.065). Results suggest that rare mass‐mortality events like the Chimney Tops 2 wildfire could play a major role in wood dynamics of mountain streams in humid forested regions. [ABSTRACT FROM AUTHOR]

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Catastrophic events, like oil spills and hurricanes, occur in many marine systems. One potential role of marine reserves is buffering populations against disturbances, including the potential for disturbance‐driven population collapses under Allee effects. This buffering capacity depends on reserves in a network providing rescue effects, setting up a tradeoff where reserves need to be connected to facilitate rescue, but also distributed in space to prevent simultaneous extinction. We use a set of population models to examine how dispersal ability and the disturbance regime interact to determine the optimal reserve spacing. We incorporate fishing in a spatially‐explicit model to understand the effect of objective choice (e.g. conservation versus fisheries yield) on the optimal reserve spacing. We show that the optimal spacing between reserves increases when accounting for catastrophes with larger spacing needed when Allee effects interact with catastrophes to increase the probability of extinction. We also show that classic tradeoffs between conservation and fishing objectives disappear in the presence of catastrophes. Specifically, we found that at intermediate levels of disturbance, it is optimal to spread out reserves in order to increase both population persistence and to maximize spillover into non‐reserve areas. [ABSTRACT FROM AUTHOR]

Over the course of 16 d in the fall of 1998, Hurricane Georges made landfall on five Caribbean Island nations, two U.S. states, and two territories. Along its path, it impacted nearly every type of built environment and terrestrial and marine ecosystem found in the Caribbean and the southeastern United States. We reviewed ecological and sociological research related to Georges in order to demonstrate the potential power of regional synoptic networks despite notable gaps that existed at the time. Most studies examined various effects and responses within four years of the storm, though a few reported longer‐term results. Reduction in forest stem density was the most reported ecological effect and ranged from 7% to 51% among sites in different forest types. Forests previously impacted by Hurricane Hugo in 1989 showed lower mortality from Georges than forests with longer hurricane‐free intervals. Rivers in the storm's path exported heavy loads of sediment to marine systems. For example, 5–10 million tons of sediment was transported to marine systems from Puerto Rico, and suspended sediments increased tenfold in coastal Louisiana. Economic costs directly related to Hurricane Georges ranged from 5% to 200% of annual GDP in the year after the storm. Sociological research indicated that children and college students exposed to Hurricane Georges experienced elevated effects on mental health such as anxiety and depression for up to 2.5 yr. Established research areas and longitudinal studies were valuable in understanding hurricane effects in the context of long‐term trends but fragmented research capacity reduced both local and regional synthetic efforts. Georges provides a template of how future integrated research programs could provide a deeper understanding of how nature, urbanization, human culture, and societal norms interact, respond, and recover from a major hurricane. However, future studies should avoid using the Saffir‐Simpson scale as a shorthand indicator or predictor of storm effects because topographic, historical, ecological, political, infrastructural, and societal factors interact to alter storm effects. The breadth of topics addressed in the research produced after Georges shows the potential for transformative, regionally synthetic research that spans whole watersheds and nearshore areas while integrating ecological and social sciences. [ABSTRACT FROM AUTHOR]