Predator control needs a standard of unbiased randomized experiments with cross-over design

Rapid, global changes, such as extinction and climate change, put a premium on evidence-based, environmental policies and interventions, including predator control efforts. Lack of solid scientific evidence precludes strong inference about responses of predators, people, and prey of both, to various types of predator control. Here we formulate two opposing hypotheses with possible underlying mechanisms and propose experiments to test four pairs of opposed predictions about responses of predators, domestic animals, and people in a coupled, dynamic system. We outline the design of a platinum-standard experiment, namely randomized, controlled experiment with cross-over design and multiple steps to blind measurement, analysis, and peer review to avoid pervasive biases. The gold-standard has been proven feasible in field experiments with predators and livestock, so we call for replicating that across the world on different methods of predator control, in addition to striving for an even higher standard that can improve reproducibility and reliability of the science of predator control

A conceptual framework for understanding illegal killing of large carnivores

The growing complexity and global nature of wildlife poaching threaten the survival of many species worldwide and are outpacing conservation efforts. Here, we reviewed proximal and distal factors, both social and ecological, driving illegal killing or poaching of large carnivores at sites where it can potentially occur. Through this review, we developed a conceptual social–ecological system framework that ties together many of the factors influencing large carnivore poaching. Unlike most conservation action models, an important attribute of our framework is the integration of multiple factors related to both human motivations and animal vulnerability into feedbacks. We apply our framework to two case studies, tigers in Laos and wolverines in northern Sweden, to demonstrate its utility in disentangling some of the complex features of carnivore poaching that may have hindered effective responses to the current poaching crisis. Our framework offers a common platform to help guide future research on wildlife poaching feedbacks, which has hitherto been lacking, in order to effectively inform policy making and enforcement

A worldwide perspective on large carnivore attacks on humans.

Large carnivores have long fascinated human societies and have profound influences on ecosystems. However, their conservation represents one of the greatest challenges of our time, particularly where attacks on humans occur. Where human recreational and/or livelihood activities overlap with large carnivore ranges, conflicts can become particularly serious. Two different scenarios are responsible for such overlap: In some regions of the world, increasing human populations lead to extended encroachment into large carnivore ranges, which are subject to increasing contraction, fragmentation, and degradation. In other regions, human and large carnivore populations are expanding, thus exacerbating conflicts, especially in those areas where these species were extirpated and are now returning. We thus face the problem of learning how to live with species that can pose serious threats to humans. We collected a total of 5,440 large carnivore (Felidae, Canidae, and Ursidae; 12 species) attacks worldwide between 1950 and 2019. The number of reported attacks increased over time, especially in lower-income countries. Most attacks (68%) resulted in human injuries, whereas 32% were fatal. Although attack scenarios varied greatly within and among species, as well as in different areas of the world, factors triggering large carnivore attacks on humans largely depend on the socioeconomic context, with people being at risk mainly during recreational activities in high-income countries and during livelihood activities in low-income countries. The specific combination of local socioeconomic and ecological factors is thus a risky mix triggering large carnivore attacks on humans, whose circumstances and frequencies cannot only be ascribed to the animal species. This also implies that effective measures to reduce large carnivore attacks must also consider the diverse local ecological and social contexts

Main published literature.

Main published literature collected and analyzed regarding large carnivore attacks, organized by species. (PDF)</p

Details of cases collected.

Details of large carnivore attacks on humans collected between 1950 and 2019 on a worldwide scale. (PDF)</p

Main attack patterns.

Main characteristics and patterns of large carnivore attacks on humans documented in our study. (PDF)</p

Complete dataset of large carnivore attacks on humans documented between 1950 and 2019.

(XLSX)</p

Spatial distribution of large carnivore attacks on humans collected between 1950 and 2019.

We collected a total of 5,440 attack cases worldwide: 1,337 involved sloth bears Melursus ursinus, 1,047 tigers Panthera tigris, 765 Asiatic black bears Ursus thibetanus, 664 brown bears Ursus arctos, 414 wolves Canis lupus, 403 American black bears Ursus americanus, 282 lions Panthera leo, 205 leopards Panthera pardus, 140 coyotes Canis latrans, 135 cougars Puma concolor, 25 jaguars Panthera onca, and 23 polar bears Ursus maritimus. The maps were produced in QGIS, and the base shapefile layer of world countries was downloaded from Natural Earth (https://www.naturalearthdata.com/downloads/10m-cultural-vectors/10m-admin-0-countries/) and do not require credit because of public domain. The data underlying this Figure can be found in S2 Data.</p

Global spatial distribution (1950–2019) of the main large carnivore attack scenarios.

Predatory attacks are especially concentrated in India and Africa, where felids and canids are primarily involved. The maps were produced in QGIS, and the base shapefile layer of world countries was downloaded from Natural Earth (https://www.naturalearthdata.com/downloads/10m-cultural-vectors/10m-admin-0-countries/) and do not require credit because of public domain. The data underlying this Figure can be found in S2 Data.</p

Temporal trends in large carnivore attacks on humans in different regions of the world.

(A) The number of attacks shows a nonlinear increase over the years, as evidenced by fitting the general additive mixed model of the number of attacks-1 as a function of the smoothing factor “year.” In particular, the number of attacks has increased in countries with (B) low CO2 emissions and (C) a high proportion of agricultural land area. In countries with (D) large forest coverage, the number of attacks in the last several years has decreased. Panels B-D are counterplots representing, respectively, the effect of the interaction between year and CO2 emissions, % of agricultural land area, and % of forest land area on number of attacks-1 from a generalized additive mixed model. The axes represent the values of the predictor variables, and the interior is a topographic map of the predicted values. The pink colors represent larger predictions and the blue ones smaller predictions. The data underlying this Figure can be found in S2 Data.</p