Earth's tropical ecosystems have witnessed several extinctions and a dramatic reduction of the range and abundance of large reptile species, which is directly related to the rise of early and modern humans. The occurrence of such extinctions, range reduction, species loss, and the consequences for several paramount ecosystem processes are poorly documented compared to other large vertebrate species. Here, I reviewed the literature on the ecological processes performed by large tropical reptile species and their human-induced widespread demise in order to determine knowledge gaps and encourage a paradigm shift in understanding on the interactiveness of such species. The interactions and species involved indicate that large abundant reptiles in the tropics are important in ecological processes, and can consequently have an important role in ecosystem function through gene dispersal, nutrient cycling, trophic action, and ecosystem engineering. These important interactions performed by reptiles are not solely performed by few species, or geographically restricted to islands, but instead present a pattern that repeatedly occurs in large reptiles distributed over tropical ecosystems. The observed tendency of reptiles to be tightly involved in these ecological interactions has important implications for the ecology of tropical ecosystems. Lost and current ecological processes performed by large reptiles may be orders of magnitude higher than what is currently perceived, and the misleading baseline of those processes must be addressed otherwise we risk losing species and services that are dependent of such interactions. To fix this bias I suggest: (a) Increase information spreading about Pleistocene-Holocene reptile extinctions using popular media; (b) Improved exchange between the research field of megafauna effects in ecosystems and herpetologists working with large reptiles; (c) Increase research effort on anthropogenic reptile extinctions and their potential to predict future losses; (d) Address the knowledge gaps, as human-reptile conflict, chelonian seed dispersal and nutrient movement; (e) Increase quantitative research on large reptile population ecology, density, and abundance. (f) address the potentially present or lost ecosystem effects of extant and extinct reptile species. Although the importance of reptiles in most tropical ecosystems has been perceived as negligible, this study shows that this may be a misleading paradigm.

Human-wildlife conflict is a widespread problem that threatens both animals and local livelihoods. When this conflict involves predators, the additional risks to human life worsen the problem. The perceptions of human-predator conflict have been investigated multiple times, usually to generate data for conflict resolution. However, such efforts have largely involved mammals from the order Carnivora. In this work, we tested hypotheses about the feeding habits of two species of constricting anacondas from the genus Eunectes and human perception of risks and attitudes associated with such habits. In particular, we investigated the consequences for the snake after predation on domestic or wild animals. We also tested the relationship between human killing of anacondas and local development indicators – a proxy for general education level. Data were obtained from internet videos using a standardized method for information retrieval. A total of 330 videos of human-anaconda encounters were recovered from ten different South American countries. We found that visual evidence of a recent meal (distended abdomen) and predation on domestic animals did not affect the probability of the anaconda being killed, but this probability increased as the Human Development Index (HDI) diminished and as anaconda size increased. Although retaliatory killing is described as one of main causes of animal mortality following human-wildlife conflicts, our results suggest that killing of anacondas are not retaliatory or related to economic losses, but preventive, because these snakes are seen as life-threatening animals. Adding social context information on human-predator conflicts, together with taxon-free research on this subject can improve our knowledge about human-wildlife conflict. Further research could focus on the actual impacts (direct or indirect) of anacondas on stakeholders, and on the role of other non-mammalian predators in human-wildlife conflicts (whether actual or perceived).

The highly interactive nature of predator-prey relationship is essential for ecosystem conservation; predators have been extirpated, however, from entire ecosystems all over the Earth. Reintroductions comprise a management technique to reverse this trend. Species Distribution Models (SDM) are preemptive tools for release-site selection, and can define levels of habitat quality over the species distribution. The Atlantic Forest of South America has lost most of its apex predators, and Harpy Eagles Harpia harpyja—Earth’s largest eagle—are now limited to few forest pockets in this domain. Harpy Eagles are supposedly widespread in the Amazon Forest, however, where habitat loss and degradation is advancing at a rapid pace. We aim to describe the suitability of threatened Amazonian landscapes for this eagle. We also aim to assess the suitability of remaining Atlantic Forest sites for Harpy Eagle reintroductions. Here we show that that considerable eagle habitat has already been lost in Amazonia due to the expansion of the “Arc of Deforestation”, and that Amazonian forests currently represent 93% of the current distribution of the species. We also show that the Serra do Mar protected areas in southeastern Brazil is the most promising region for Harpy Eagle reintroductions in the Atlantic Forest. Reintroduction and captive breeding programs have been undertaken for Harpy Eagles, building the technical and biological basis for a successful restoration framework. Our distribution range for this species represents a 41% reduction of what is currently proposed by IUCN. Furthermore, habitat loss in Amazonia, combined with industrial logging and hunting suggest that the conservation status of this species should be reassessed. We suggest researchers and conservation practitioners can use this work to help expand efforts to conserve Harpy Eagles and their natural habitats.

Understanding species–environment relationships is key to defining the spatial structure of species distributions and develop effective conservation plans. However, for many species, this baseline information does not exist. With reliable presence data, spatial models that predict geographic ranges and identify environmental processes regulating distribution are a cost‐effective and rapid method to achieve this. Yet these spatial models are lacking for many rare and threatened species, particularly in tropical regions. The harpy eagle (Harpia harpyja) is a Neotropical forest raptor of conservation concern with a continental distribution across lowland tropical forests in Central and South America. Currently, the harpy eagle faces threats from habitat loss and persecution and is categorized as Near‐Threatened by the International Union for the Conservation of Nature (IUCN). Within a point process modeling (PPM) framework, we use presence‐only occurrences with climatic and topographical predictors to estimate current and past distributions and define environmental requirements using Ecological Niche Factor Analysis. The current PPM prediction had high calibration accuracy (Continuous Boyce Index = 0.838) and was robust to null expectations (pROC ratio = 1.407). Three predictors contributed 96% to the PPM prediction, with Climatic Moisture Index the most important (72.1%), followed by minimum temperature of the warmest month (15.6%) and Terrain Roughness Index (8.3%). Assessing distribution in environmental space confirmed the same predictors explaining distribution, along with precipitation in the wettest month. Our reclassified binary model estimated a current range size 11% smaller than the current IUCN range polygon. Paleoclimatic projections combined with the current model predicted stable climatic refugia in the central Amazon, Guyana, eastern Colombia, and Panama. We propose a data‐driven geographic range to complement the current IUCN range estimate and that despite its continental distribution, this tropical forest raptor is highly specialized to specific environmental requirements.

Apex predators are threatened globally, and their local extinctions are often driven by failures in sustaining prey acquisition under contexts of severe prey scarcity. The harpy eagleHarpia harpyjais Earth’s largest eagle and the apex aerial predator of Amazonian forests, but no previous study has examined the impact of forest loss on their feeding ecology. We monitored 16 active harpy eagle nests embedded within landscapes that had experienced 0 to 85% of forest loss, and identified 306 captured prey items. Harpy eagles could not switch to open-habitat prey in deforested habitats, and retained a diet based on canopy vertebrates even in deforested landscapes. Feeding rates decreased with forest loss, with three fledged individuals dying of starvation in landscapes that succumbed to 50–70% deforestation. Because landscapes deforested by > 70% supported no nests, and eaglets could not be provisioned to independence within landscapes > 50% forest loss, we established a 50% forest cover threshold for the reproductive viability of harpy eagle pairs. Our scaling-up estimate indicates that 35% of the entire 428,800-km²Amazonian ‘Arc of Deforestation’ study region cannot support breeding harpy eagle populations. Our results suggest that restoring harpy eagle population viability within highly fragmented forest landscapes critically depends on decisive forest conservation action.

Aim: A current biogeographic paradigm states that climate regulates species distributions at continental scales and that biotic interactions are undetectable at coarse‐grain extents. However, advances in spatial modelling show that incorporating food resource distributions are important for improving model predictions at large distribution scales. This is particularly relevant to understand the factors limiting the distribution of widespread apex predators whose diets are likely to vary across their range.Location: Neotropical Central and South America.Methods: The harpy eagle (Harpia harpyja) is a large raptor, whose diet is largely comprised of arboreal mammals, all with broad distributions across Neotropical lowland forest. Here, we used a hierarchical modelling approach to determine the relative importance of abiotic factors and prey resource distribution on harpy eagle range limits. Our hierarchical approach consisted of the following modelling sequence of explanatory variables: (a) abiotic covariates, (b) prey resource distributions predicted by an equivalent modelling for each prey, (c) the combination of (a) and (b), and (d) as in (c) but with prey resources considered as a single prediction equivalent to prey species richness.Results: Incorporating prey distributions improved model predictions but using solely biotic covariates still resulted in a high‐performing model. In the Abiotic model, Climatic Moisture Index (CMI) was the most important predictor, contributing 76% to model prediction. Three‐toed sloth (Bradypus spp.) was the most important prey resource, contributing 64% in a combined Abiotic‐Biotic model, followed by CMI contributing 30%. Harpy eagle distribution had high environmental overlap across all individual prey distributions, with highest coincidence through Central America, eastern Colombia, and across the Guiana Shield into northern Amazonia.Main Conclusions: With strong reliance on prey distributions across its range, harpy eagle conservation programmes must therefore consider its most important food resources as a key element in the protection of this threatened raptor.