Situating defaunation in an operational framework to advance biodiversity conservation.

Anthropogenic pressures are causing the widespread loss of wildlife species and populations, with adverse consequences for ecosystem functioning. This phenomenon has been widely but inconsistently referred to as defaunation. A cohesive, quantitative framework for defining and evaluating defaunation is necessary for advancing biodiversity conservation. Likening defaunation to deforestation, we propose an operational framework for defaunation that defines it and related terms, situates defaunation relative to intact communities and faunal degradation, and encourages quantitative, ecologically reasonable, and equitable measurements. We distinguish between defaunation, the conversion of an ecosystem from having wild animals to not having wild animals, and faunal degradation, the process of losing animals or species from an animal community. The quantification of context-relevant defaunation boundaries or baselines is necessary to compare faunal communities over space and time. Situating a faunal community on the degradation curve can promote Global Biodiversity Framework targets, advancing the 2050 Vision for Biodiversity.

How Does Changing Environment Influence Plant Seed Movements as Populations of Dispersal Vectors Decline?

Plants differ widely in their ability to find tolerable climatic ranges through seed dispersal, depending on their life-history traits and habitat characteristics. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic review on seed dispersal mechanisms was conducted to elucidate plant seed movements amid changing environments. Here, the highest relative count of studies was found in Spain (16.47%), followed by Brazil (14.12%), and the USA (14.12%). The megadiverse, hotspot countries (e.g., Philippines, Vietnam, Myanmar, India, and Indonesia) and Africa (Tanzania, South Africa, Democratic Republic of the Congo) have very low to no data about the reviewed topic. The effects of land use changes, habitat degradation/disturbances, climate, and extreme weather conditions on seed dispersal mechanisms and agents had the highest share of studies across topics and countries. Plant diversity and distribution of anemochorous, endozoochorous, epizoochorous, hydrochorous, myrmecochorous, and ornithochorous species are seriously affected by changing environments due to altered long-distance seed dispersal. The fruit types commonly associated with endozoochory and ornithochory are species with achene, capsule, drupe, fleshy, and nut fruits/seeds, whereas achene, capsule, samara/winged seeds are associated with anemochory. The present review provides a summary of evidence on how plants are affected by climate change as populations of dispersal vectors decline. Finally, recommendations for further study were made based on the identified knowledge gaps.

Terrestrial food web complexity in Amazonian forests decays with habitat loss.

The conversion of natural ecosystems into human-modified landscapes (HMLs) is the main driver of biodiversity loss in terrestrial ecosystems.1,2,3 Even when species persist within habitat remnants, populations may become so small that ecological interactions are functionally lost, disrupting local interaction networks.4,5 To uncover the consequences of land use changes toward ecosystem functioning, we need to understand how changes in species richness and abundance in HMLs6,7,8 rearrange ecological networks. We used data from forest vertebrate surveys and combined modeling and network analysis to investigate how the structure of predator-prey networks was affected by habitat insularization induced by a hydroelectric reservoir in the Brazilian Amazonia.9 We found that network complexity, measured by interaction diversity, decayed non-linearly with decreasingly smaller forest area. Although on large forest islands (>100 ha) prey species were linked to 3-4 potential predators, they were linked to one or had no remaining predator on small islands. Using extinction simulations, we show that the variation in network structure cannot be explained by abundance-related extinction risk or prey availability. Our findings show that habitat loss may result in an abrupt disruption of terrestrial predator-prey networks, generating low-complexity ecosystems that may not retain functionality. Release from predation on some small islands may produce cascading effects over plants that accelerate forest degradation, whereas predator spillover on others may result in overexploited prey populations. Our analyses highlight that in addition to maintaining diversity, protecting large continuous forests is required for the persistence of interaction networks and related ecosystem functions.

Seagrass ecosystem multifunctionality under the rise of a flagship marine megaherbivore.

Large grazers (megaherbivores) have a profound impact on ecosystem functioning. However, how ecosystem multifunctionality is affected by changes in megaherbivore populations remains poorly understood. Understanding the total impact on ecosystem multifunctionality requires an integrative ecosystem approach, which is especially challenging to obtain in marine systems. We assessed the effects of experimentally simulated grazing intensity scenarios on ecosystem functions and multifunctionality in a tropical Caribbean seagrass ecosystem. As a model, we selected a key marine megaherbivore, the green turtle, whose ecological role is rapidly unfolding in numerous foraging areas where populations are recovering through conservation after centuries of decline, with an increase in recorded overgrazing episodes. To quantify the effects, we employed a novel integrated index of seagrass ecosystem multifunctionality based upon multiple, well-recognized measures of seagrass ecosystem functions that reflect ecosystem services. Experiments revealed that intermediate turtle grazing resulted in the highest rates of nutrient cycling and carbon storage, while sediment stabilization, decomposition rates, epifauna richness, and fish biomass are highest in the absence of turtle grazing. In contrast, intense grazing resulted in disproportionally large effects on ecosystem functions and a collapse of multifunctionality. These results imply that (i) the return of a megaherbivore can exert strong effects on coastal ecosystem functions and multifunctionality, (ii) conservation efforts that are skewed toward megaherbivores, but ignore their key drivers like predators or habitat, will likely result in overgrazing-induced loss of multifunctionality, and (iii) the multifunctionality index shows great potential as a quantitative tool to assess ecosystem performance. Considerable and rapid alterations in megaherbivore abundance (both through extinction and conservation) cause an imbalance in ecosystem functioning and substantially alter or even compromise ecosystem services that help to negate global change effects. An integrative ecosystem approach in environmental management is urgently required to protect and enhance ecosystem multifunctionality.

Loss of endangered frugivores from seed dispersal networks generates severe mutualism disruption.

Many tropical seed-dispersing frugivores are facing extinction, but the consequences of the loss of endangered frugivores for seed dispersal is not well understood. We investigated the role of frugivore endangerment status via robustness-to-coextinction simulations (in this context, more accurately described as robustness-to-partner-loss simulations) using data from the Brazilian Atlantic Forest biodiversity hotspot. By simulating the extinction of endangered frugivores, we found a rapid and disproportionate loss of tree species with dispersal partners in the network, and this surprisingly surpassed any other frugivore extinction scenario, including the loss of the most generalist frugivores first. A key driver of this pattern is that many specialist plants rely on at-risk frugivores as seed-dispersal partners. Moreover, interaction compensation in the absence of endangered frugivores may be unlikely because frugivores with growing populations forage on fewer plant species than frugivores with declining populations. Therefore, protecting endangered frugivores could be critical for maintaining tropical forest seed dispersal, and their loss may have higher-than-expected functional consequences for tropical forests, their regeneration processes, and the maintenance of tropical plant diversity.

Savanna vegetation increase triggers freshwater community shifts.

Tropical savannas are globally extensive and ecologically invaluable ecosystems. As most ecosystems however, they are subject to serious anthropogenic stress. Defaunation, and especially the loss of large mammals, is pervasive in tropical savannas and known to trigger wide-ranging ecological effects, from vegetation changes to the loss of ecosystem function. Despite what is currently known about the terrestrial consequences of defaunation, and the potential cross-ecosystem influence of large mammals, virtually no research has investigated associated effects on small adjacent water bodies. This research gap persists because (1) tropical savannas have been historically neglected, (2) the ecological value of small water bodies (e.g. ponds) is only recently being recognized, and (3) empirical baseline data are often lacking. In this paper, we compared a rare pre-change dataset with newly collected data on 213 freshwater assemblages, to investigate community structure and composition before and after a major defaunation event. Our research focused on a diverse species assemblage of amphibian larvae (i.e. tadpoles) in temporary savanna ponds. We found that pond vegetation cover increased from 16.0% to 45.6% post-defaunation, that is, a near three-fold increase. Such habitat changes seemed to have benefitted those species that use vegetation during reproduction (e.g. the leaf-folding Afrixalus spp.), while others have declined. Interestingly, we found a strong correlation between tadpole community shifts and other freshwater organisms, which indicates that habitat changes have affected a wide variety of aquatic organisms. Given that organisms inhabiting temporary aquatic habitats often have complex life histories with terrestrial adult life stages, we propose that the terrestrial effects of defaunation have indirectly led to distinct aquatic communities, in addition to direct habitat effects. These results shed new light on the potential role of large-bodied mammals in shaping adjacent ecosystems, and raise important questions concerning the functioning of temporary aquatic systems in the Anthropocene.

Les savanes tropicales sont des écosystèmes étendus à l'échelle mondiale et d'une valeur écologique inestimable, mais qui sont soumis à une pression anthropique croissante. La défaunation, en particulier la perte de grands mammifères, est omniprésente dans les savanes tropicales et pouvant déclencher des effets écologiques de grande envergure allant des changements de végétation à la perte des fonctions écosystémiques. Malgré ce qui est connu des conséquences terrestres de la défaunation, presque aucune recherche n'a étudié les effets de la défaunation sur les plans d'eau temporaires adjacents qui sont utilisés par les grands mammifères. Cette lacune persiste parce que (1) les savanes tropicales ont été historiquement négligées, (2) la valeur écologique des plans d'eau temporaires a souvent été sous-estimée et (3) les données empiriques de référence sont souvent absentes. Dans l'étude présente, nous avons utilisé des données pré/post-défaunation sur 213 assemblages aquatiques de savane, dans le but d'étudier la structure et la composition de ces communités avant et après qu'un événement majeur de défaunation ait eu lieu. Notre recherche se focalise sur des plans d'eau temporaire comptant un nombre important d'espèces de larves d'amphibiens (têtards). Nous avons détecté une multiplication moyenne par près de trois de la couverture végétale des plans d'eau après la défaunation (16,0% à 45,6%). Ces changements d'habitat semblent avoir profité aux espèces qui utilisent la végétation pour leur reproduction (par exemple, Afrixalus spp.), tandis que d'autres espèces avec d'autres préférences d'habitat ont décliné. Nous avons calculé une forte corrélation entre la composition des têtards et celle de leurs prédateurs, ce qui indique que les changements d'habitat ont affecté la plupart des membres de ces communautés aquatiques. Étant donné que les organismes d'habitats aquatiques temporaires ont pour la plupart un cycle biologique complexe figurant à la fois un stade larvaire aquatique et un stade adulte terrestre, nous proposons qu'en plus des effets directs sur l'habitat aquatique (augmentation de la végétation), les effets terrestres de la défaunation ont indirectement altéré les communautés. Ces résultats suggèrent un rôle important des grands mammifères par leur influence sur les écosystèmes aquatique adjacents et soulèvent des questions urgentes concernant la fonctionnalité des systèmes aquatiques temporaires dans l'Anthropocène.

Detangling ecosystem services: Open-field manipulation of soil-dwelling microarthropods provides new opportunities to investigate their effects on nitrogen cycling.

Soil microarthropods have a pivotal role in soil nitrogen cycling in that they affect microbial decomposers. A high abundance of microarthropods may increase the mobility of inorganic nitrogen ions in the soil, mainly in nitrogen-limited habitats. However, it is difficult to study ecological processes with small-sized, soil-dwelling arthropods. The effects of soil microarthropods on nitrogen cycling have mainly been studied in laboratory microcosm experiments. Therefore, we face many practical issues in investigating these effects under field conditions that remain to be resolved.We developed an open-field mesocosm setup with growing plants. In a two-part experiment, spring wheat and grass species were grown in chernozem and sandy soils. Leached ammonium and nitrate ions were measured with percolation lysimeters. Half of the mesocosms included natural assemblages, and the other half included less abundant Acari and Collembola assemblages. The application of nitrogen fertilization assured differences in nitrogen sources.We found a large difference in ammonium and nitrate leaching between the two soil types. In chernozem soil, the leached ion concentrations were higher in mesocosms with more abundant mite and springtail assemblages. The expected patterns were less pronounced in sandy soil. Adding nitrogen fertilizer did not modify the effects of soil microarthropods.Open-field mesocosms are promising for studying the role of soil-dwelling mesofauna in ecological processes. We solved the problem of keeping mesofauna abundance lower in treated plots than that in control plots. Plants successfully grew in our semi-closed systems with functioning percolation lysimeters. The use of the equipment in the experiments in this study helped reveal that the role of soil-dwelling microarthropods in nitrogen cycling depends on the soil type and not on the application of nitrogen fertilizer.

Climate-driven divergent long-term trends of forest beetles in Japan.

Concerning declines in insect populations have been reported from Europe and the United States, yet there are gaps in our knowledge of the drivers of insect trends and their distribution across the world. We report on our analysis of a spatially extensive, 14-year study of ground-dwelling beetles in four natural forest biomes spanning Japan's entire latitudinal range (3000 km). Beetle species richness, abundance and biomass declined in evergreen coniferous forests but increased in broadleaf-coniferous mixed forests. Further, beetles in evergreen coniferous forests responded negatively to increased temperature and precipitation anomalies, which have both risen over the study's timespan. These significant changes parallel reports of climate-driven changes in forest tree species, providing further evidence that climate change is altering forest ecosystems fundamentally. Given the enormous biodiversity and ecosystem services that forests support globally, the implications for biodiversity change resulting from climate change could be profound.

What Caused Declines in Intertidal Invertebrate Populations around Fukushima Daiichi Nuclear Power Plant after the 2011 Great East Japan Earthquake, Tsunami, and Nuclear Disaster?

We discuss possible causal factors for the decline in intertidal invertebrate populations around Fukushima Daiichi Nuclear Power Plant (FDNPP) after the 2011 Great East Japan Earthquake and subsequent tsunami and nuclear disaster on the basis of existing knowledge about the effects of radionuclides and ionizing radiation on aquatic organisms. We found a gap between effects observed in the laboratory and those observed in natural aquatic environments, and discuss possible reasons why. Considering the complexity of the environment, we conclude that it is critical to evaluate the effects of ionizing radiation combined with other biotic and abiotic environmental factors, together with the life-history traits of the species examined, for realistic assessment of population-level effects. Finally, we present possible causal factors for strange or abnormal phenomena observed in intertidal biota near FDNPP, namely declines in population densities and number of species of invertebrates, delayed recovery from these declines, and continuous sexual maturation in the rock shell population.

The effect of past defaunation on ranges, niches, and future biodiversity forecasts.

Humans have reshaped the distribution of biodiversity across the globe, extirpating species from regions otherwise suitable and restricting populations to a subset of their original ranges. Here, we ask if anthropogenic range contractions since the Late Pleistocene led to an under-representation of the realized niches for megafauna, an emblematic group of taxa often targeted for restoration actions. Using reconstructions of past geographic distributions (i.e., natural ranges) for 146 extant terrestrial large-bodied (>44 kg) mammals, we estimate their climatic niches as if they had retained their original distributions and evaluate their observed niche dynamics. We found that range contractions led to a sizeable under-representation of the realized niches of several species (i.e., niche unfilling). For 29 species, more than 10% of the environmental space once seen in their natural ranges has been lost due to anthropogenic activity, with at least 12 species undergoing reductions of more than 50% of their realized niches. Eighteen species may now be confined to low-suitability locations, where fitness and abundance are likely diminished; we consider these taxa 'climatic refugees'. For those species, conservation strategies supported by current ranges risk being misguided if current, suboptimal habitats are considered baseline for future restoration actions. Because most climate-based biodiversity forecasts rely exclusively on current occurrence records, we went on to test the effect of neglecting historical information on estimates of species' potential distribution - as a proxy of sensitivity to climate change. We found that niche unfilling driven by past range contraction leads to an overestimation of sensitivity to future climatic change, resulting in 50% higher rates of global extinction, and underestimating the potential for megafauna conservation and restoration under future climate change. In conclusion, range contractions since the Late Pleistocene have also left imprints on megafauna realized climatic niches. Therefore, niche truncation driven by defaunation can directly affect climate and habitat-based conservation strategies.

How the loss of forest fauna undermines the achievement of the SDGs.

The human-driven loss of biodiversity has numerous ecological, social, and economic impacts at the local and global levels, threatening important ecological functions and jeopardizing human well-being. In this perspective, we present an overview of how tropical defaunation-defined as the disappearance of fauna as a result of anthropogenic drivers such as hunting and habitat alteration in tropical forest ecosystems-is interlinked with four selected Sustainable Development Goals (SDGs). We discuss tropical defaunation related to nutrition and zero hunger (SDG 2), good health and well-being (SDG 3), climate action (SDG 13), and life on land (SDG 15). We propose a range of options on how to study defaunation in future research and how to address the ongoing tropical defaunation crisis, including but not limited to recent insights from policy, conservation management, and development practice.

Homogenization of terrestrial mammals in fragmented rainforests: the loss of species turnover and its landscape drivers.

Understanding the factors and mechanisms shaping differences in species composition across space and time (ß-diversity) in human-modified landscapes has key ecological and applied implications. This topic is, however, challenging because landscape disturbance can promote either decreases (biotic homogenization) or increases (biotic differentiation) in ß-diversity. We assessed temporal differences in intersite ß-diversity of medium-bodied and large-bodied mammals in the fragmented Lacandona rainforest, Mexico. We hypothesized that, given the relatively short history of land-use changes in the region, and the gain and loss of some species caused by landscape spatial changes, ß-diversity would increase through time, especially its nestedness component. We estimated ß-diversity between 24 forest sites (22 forest patches and two continuous forest sites) in 2011 and 2017 to assess whether ß-diversity is decreasing or increasing in the region, and calculated its turnover and nestedness components to understand the mechanisms responsible for changes in ß-diversity, separately assessing mammal groups with different body mass, feeding guild, and habitat specialization. We then related such temporal changes in ß-diversity to temporal changes in five landscape variables (forest cover, matrix openness, number of patches, edge density and interpatch distance) to identify the landscape drivers of ß-diversity. In contrast with our expectations, ß-diversity decreased over time, suggesting an ongoing biotic homogenization process. This pattern was mostly driven by a decrease in species turnover in all mammal groups, especially in landscapes with decreasing forest cover and increasing forested matrices. Although the nestedness component showed a three-fold increase through time, species turnover was 22 and six times higher than nestedness in 2011 and 2017, respectively. The decreased turnover appears to be driven by an increase in dispersal (i.e., spillover) of native species among patches. The prevalence of species turnover over nestedness indicates that different forest sites have a fairly distinct subset of species (i.e., high complementarity in species composition). Therefore, conserving all remaining forest patches and increasing forest cover is of utmost importance to effectively maintain ß-diversity and conserve the total diversity (γ) of mammal assemblages in this Mesoamerican biodiversity hotspot.

Large herbivores suppress liana infestation in an African savanna.

African savannas are the last stronghold of diverse large-mammal communities, and a major focus of savanna ecology is to understand how these animals affect the relative abundance of trees and grasses. However, savannas support diverse plant life-forms, and human-induced changes in large-herbivore assemblages-declining wildlife populations and their displacement by livestock-may cause unexpected shifts in plant community composition. We investigated how herbivory affects the prevalence of lianas (woody vines) and their impact on trees in an East African savanna. Although scarce (<2% of tree canopy area) and defended by toxic latex, the dominant liana, Cynanchum viminale (Apocynaceae), was eaten by 15 wild large-herbivore species and was consumed in bulk by native browsers during experimental cafeteria trials. In contrast, domesticated ungulates rarely ate lianas. When we experimentally excluded all large herbivores for periods of 8 to 17 y (simulating extirpation), liana abundance increased dramatically, with up to 75% of trees infested. Piecewise exclusion of different-sized herbivores revealed functional complementarity among size classes in suppressing lianas. Liana infestation reduced tree growth and reproduction, but herbivores quickly cleared lianas from trees after the removal of 18-y-old exclosure fences (simulating rewilding). A simple model of liana contagion showed that, without herbivores, the long-term equilibrium could be either endemic (liana-tree coexistence) or an all-liana alternative stable state. We conclude that ongoing declines of wild large-herbivore populations will disrupt the structure and functioning of many African savannas in ways that have received little attention and that may not be mitigated by replacing wildlife with livestock.

Effects on Brood Development in the Carpenter Ant Camponotus vicinus Mayr after Exposure to the Yeast Associate Schwanniomyces polymorphus Kloecker.

The yeast Schwanniomyces polymorphus is associated with the infrabuccal pocket in the carpenter ant Camponotus vicinus (Hymenoptera: Formicidae), but its role in ant development is poorly defined. The potential effects of this yeast on brood development were examined on sets of larval groups and workers over a 12 week period. Worker-larval sets were fed variations of a completely artificial, holidic diet and exposed or not exposed to live S. polymorphus. Worker-larval sets in half of the experiment were defaunated using a two-step heat and chemical process. Brood development and number of adult ants produced were significantly affected by the heat/chemical defaunation process. Compared to worker-larval groups fed a basal, complete diet, all treatments resulted in no or deleterious larval development. Brood weights and number of worker ants produced from the original larval sets at initiation were significantly higher in non-defaunated ant groups fed a diet lacking both B vitamins and cholesterol and exposed to live S. polymorphus. We propose that this yeast may help ants to more efficiently assimilate nutrients when fed nutrient-deficient diets, particularly those deficient in sterols.

Las cabras como dispersores de semillas: aportes y limitaciones para la regeneración del bosque tropical estacionalmente seco de Ecuador / Goats as seed dispersers: contributions and limitations for the regeneration of the seasonally dry tropical forest in Ecuador

Resumen Introducción: Los bosques tropicales estacionalmente secos están sujetos a procesos de degradación crónica que ponen en riesgo su diversidad. La ganadería intensiva dentro de los remanentes de bosque se plantea como una de las principales causas de estos procesos de degradación. Sin embargo, el ganado también podría estar cumpliendo el rol de dispersor de semillas para algunas especies. Objetivo: Evaluar el rol de las cabras en la dispersión de semillas de especies leñosas y las posibles consecuencias de su comportamiento alimenticio sobre la estructura de la vegetación. Métodos: Entre diciembre 2016 y junio 2017 se recolectaron fecas de corrales (N = 38) y parcelas de vegetación (N = 42) de tres localidades de bosque seco en el Suroccidente de Ecuador. Todas las semillas encontradas en las fecas (N = 13 326) se registraron e identificaron taxonómicamente. Para evaluar el efecto de la ingestión de semillas sobre la germinación, se estableció un experimento de siembra de semillas extraídas de fecas procedentes de corrales y semillas recolectadas directamente de la planta. Resultados: Las cabras dispersaron 10 especies leñosas, de las cuales al menos el 50 % son leguminosas. Las semillas de Acacia macracantha representaron más del 70 % de semillas presentes en fecas de cabra. El paso de semillas por el tracto digestivo de las cabras mejoró significativamente el porcentaje y velocidad de germinación en Albizia multiflora, Piscidia carthagenensis y Ziziphus thyrsiflora, mientras que en Choroleucon mangense y Prosopis juliflora no se obtuvo germinación. No encontramos una correlación entre la riqueza de árboles establecidos y el número de especies encontradas en las fecas (χ2 = -0.23, P = 0.53). La composición de especies de semillas dispersadas en las fecas no mostró una dependencia de la localidad, a pesar de que la composición de la vegetación establecida cambia entre localidades. La abundancia de semillas en las fecas no mostró relación con la abundancia de árboles en la vegetación establecida. Conclusiones: Las cabras pueden suplir en cierta medida el rol de otros ungulados localmente extintos, mejorando la germinación de especies de leguminosas con testa dura. Sin embargo, su comportamiento alimenticio y la alta dominancia en la dispersión de ciertas especies puede tener importantes efectos en la estructura de la comunidad.

Abstract Introduction: Seasonally dry tropical forests are subject to chronic degradation processes, which has reduced the populations of some important animal dispersers. Intensive livestock farming within the forest remnants is considered one of the main causes of these degradation processes. However, domestic ungulates could also be fulfilling the role of seed dispersal for some wild species. Objective: To evaluate the role of goats as seed dispersers of woody species and the possible consequences of their feeding behavior on the vegetation structure. Methods: Between December 2016 and June 2017, we collected goat feces from pens (N = 38) and vegetation plots (N = 42) from three locations of dry forest in the Southwestern Ecuador. All the seeds found in the feces (N = 13 326) were recorded and taxonomically identified. To evaluate the effect of gut passage on seed germination, we sowed the seeds found in the goat feces from the pens and seeds collected directly from parent plants. Results: Goats dispersed seeds from ten species, of which at least 50 % are legumes. Acacia macracantha seeds represented ca. 70 % of seeds present in goat feces. The passage of seeds through the digestive tract of goats significantly improved the percentage and speed of germination in Albizia multiflora, Piscidia carthagenensis and Ziziphus thyrsiflora, while in Choroleucon mangense and Prosopis juliflora no germination was registered. We did not find a correlation between the richness of established trees and the number of species found in the goat feces (χ2 = -0.23, P = 0.53). The composition of dispersed seed species in the feces did not show a dependency on the locality, although the composition of the established vegetation changes between localities. The frequency of seeds in the feces did not show a relationship with the tree abundance in the established vegetation. Conclusions: Goats can play, at least partially, the role of locally extinct wild ungulates, improving the germination of legume species with hard coat. However, this positive effect can be blurred by their feeding behavior and high preference for particular species, which can modify the dominance of some species, and result in changes in the composition and structure of the vegetation.

Historical and current distribution ranges and loss of mega-herbivores and carnivores of Asia.

Ecosystem functioning is dependent a lot on large mammals, which are, however, vulnerable and facing extinction risks due to human impacts mainly. Megafauna of Asia has been declining for a long, not only in numbers but also in their distribution ranges. In the current study, we collected information on past and current occurrence and distribution records of Asia's megafauna species. We reconstructed the historical distribution ranges of the six herbivores and four carnivores for comparison with their present ranges, to quantify spatially explicit levels of mega-defaunation. Results revealed that historically the selected megafauna species were more widely distributed than at current. Severe range contraction was observed for the Asiatic lion, three rhino species, Asian elephant, tigers, and tapirs. Defaunation maps generated have revealed the vanishing of megafauna from parts of the East, Southeast, and Southwest Asia, even some protected Areas losing up to eight out of ten megafaunal species. These defaunation maps can help develop future conservation policies, to save the remaining distribution ranges of large mammals.

Assessment of ecological health of Swarnamukhi river estuary, southeast coast of India, through AMBI indices and multivariate tools.

A combination of biotic indices, geo-accumulation (Igeo) index, and a multivariate approach were applied to assess the anthropogenic influence on the benthic community at five stations from 2018 to 2019 in the Swarnamukhi river estuary, Nellore, India. Non-metric multidimensional scaling and cluster analysis indicated that the Buckingham canal (BC) station showed azoic conditions and formed a separate cluster. Strong positive factor loadings of Cd (0.96), Al (0.93), Zn (0.91), Fe (0.90), Co (0.89), Cu (0.89), Ni (0.87), Pb (0.85), Cr (0.77), organic matter (0.94), Silt (0.92), and clay (0.93) and negative loading of sand (-0.90) showed the variability in sediment. AMBI results illustrated the disturbance status of each station and classified BC station as 'extremely disturbed' class, and M-AMBI assessed the ecological status as 'bad'. The Igeo index also revealed metal (Cd) contamination. The present study illustrated that the combined approach is effective for ecological assessment of coastal ecosystem.

The resilient frugivorous fauna of an urban forest fragment and its potential role in vegetation enrichment.

Anthropocentric defaunation affects critical ecological processes, such as seed dispersal, putting ecosystems and biomes at risk, and leading to habitat impoverishment. Diverse restoration techniques could reverse the process of habitat impoverishment. However, in most of the restoration efforts, only vegetation cover is targeted. Fauna and flora are treated as isolated components, neglecting a key component of ecosystems' functioning, the ecological interactions. We tested whether the resilient frugivorous generalist fauna can improve habitat quality by dispersing native plant species through the use of fruit feeders as in a semideciduous seasonal urban forest fragment. A total of 32 sampling points was selected at a heavily degraded 251-ha urban forest fragment, with feeders installed at two heights monitored by camera-traps. Variable quantities of native fruits of 27 zoochorous species were offered alternately in the feeders. Based on more than 36,000 h of video records, Turdus leucomelas (Class Aves), Sapajus nigritus (Class Mammalia), and Salvator merianae (Class Reptilia) were recorded ingesting the highest fruit species richness. Didelphis albiventris (Class Mammalia) was the most frequent visitor but consumed only pulp in most of the visits. The frugivorous birds were recorded at a high visitation rate and consumed a wider variety of fruits. Our study opens a new avenue to combine the traditional approach of ecosystems recovery and ecological interactions restauration in an urban forest fragment. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11252-020-01080-5.

Long-term change in the avifauna of undisturbed Amazonian rainforest: ground-foraging birds disappear and the baseline shifts.

How are rainforest birds faring in the Anthropocene? We use bird captures spanning > 35 years from 55 sites within a vast area of intact Amazonian rainforest to reveal reduced abundance of terrestrial and near-ground insectivores in the absence of deforestation, edge effects or other direct anthropogenic landscape change. Because undisturbed forest includes far fewer terrestrial and near-ground insectivores than it did historically, today's fragments and second growth are more impoverished than shown by comparisons with modern 'control' sites. Any goals for bird community recovery in Amazonian second growth should recognise that a modern bird community will inevitably differ from a baseline from > 35 years ago. Abundance patterns driven by landscape change may be the most conspicuous manifestation of human activity, but biodiversity declines in undisturbed forest represent hidden losses, possibly driven by climate change, that may be pervasive in intact Amazonian forests and other systems considered to be undisturbed.

Understanding the distribution of bushmeat hunting effort across landscapes by testing hypotheses about human foraging.

Mitigating the massive impacts of defaunation on natural ecosystems requires understanding and predicting hunting effort across the landscape. But such understanding has been hindered by the difficulty of assessing the movement patterns of hunters in thick forests and across complex terrain. We statistically tested hypotheses about the spatial distribution of hunting with circuit theory and structural equation models. We used a data set of >7000 known kill locations in Guyana and hunter movement models to test these methods. Comparing models with different resistance layers (i.e., different estimates of how terrain and land cover influence human movement speed) showed that rivers, on average, limited movement rather than serving as transport arteries. Moreover, far more kills occurred close to villages than in remote areas. This, combined with the lack of support for structural equation models that included latent terms for prey depletion driven by past overhunting, suggests that kill locations in this system tended to be driven by where hunters were currently foraging rather than by influences of historical harvest. These analyses are generalizable to a variety of ecosystems, species, and data types, providing a powerful way of enhancing maps and predictions of hunting effort across complex landscapes.

Comprensión de la Distribución de los Esfuerzos por Obtener Carne de Caza a lo largo de un Paisaje Mediante la Comprobación de Hipótesis sobre el Forrajeo Humano Resumen La mitigación de los impactos masivos de la defaunación sobre los ecosistemas naturales requiere de comprensión y predicción de los esfuerzos de caza a lo largo del paisaje. Dicha comprensión se ha visto obstaculizada por la dificultad que representa la evaluación de los patrones de movimiento de los cazadores en bosques densos y a través de un terreno complejo. Analizamos estadísticamente las hipótesis sobre la distribución espacial de la cacería mediante una teoría de circuito y modelos de ecuaciones estructurales. Usamos un conjunto de datos de más de 7000 localidades conocidas de sacrificios en Guayana y los modelos de movimiento de los cazadores para probar estos modelos. La comparación entre modelos con diferentes capas de resistencia (es decir, diferentes estimaciones de cómo el terreno y la cobertura de suelo influyen sobre la velocidad del movimiento humano) mostró que los ríos, en promedio, limitaron el movimiento en lugar de funcionar como arterias de transporte. Además, ocurrieron mucho más sacrificios cerca de las aldeas que en las áreas remotas. Lo anterior, combinado con la falta de apoyo para los modelos de ecuaciones estructurales que incluyeron los términos latentes para la reducción de presas causada por la sobrecaza pasada, sugiere que las localidades de sacrificios en este sistema tendieron a ser seleccionadas por la ubicación actual en la que los cazadores se encontraban forrajeando y no por la influencia de la cosecha histórica. Estos análisis son generalizables para una variedad de ecosistemas, especies y tipos de datos, lo que proporciona una manera poderosa de mejorar los mapas y las predicciones de los esfuerzos de cacería a través de paisajes complejos.