No abstract

The mammalian and avian assemblages of intact tropical forests are among the most diverse vertebrate communities on Earth and influence the structure, composition, and functioning of these forests in myriad ways. Over recent centuries, however, increasing human domination of the tropics has led to widespread defaunation, or the decline, local-, or global extinction of tropical animal species. Defaunation is one of the defining features of the Anthropocene and is best documented for vertebrate species, especially mammals and birds. Defaunation is driven by several direct (e.g., hunting) and indirect (e.g., habitat alteration) anthropogenic threats, but how these threats differ in the nature and magnitude of their impacts on tropical mammal and bird species remains unclear. Using a meta-analysis of 82 studies on 254 mammal and 1,640 bird species from across the tropics, we assess the effects of three major regionalscale drivers of tropical defaunation, namely hunting, forest degradation and forest conversion, on measures of abundance for tropical mammal and bird species belonging to different dietary guilds and IUCN conservation status groups. Mammal species across dietary guilds either declined or did not change, on average, in response to the three drivers, with hunting having the most consistent negative impacts on abundances of carnivores, frugivores, herbivores/granivores, large-bodied species, and species of high conservation importance. By contrast, bird species declined most strongly in response to forest conversion, with responses varying widely across different dietary and conservation importance groups, and not consistently related to body size. Our results reveal that hunting, forest degradation and conversion are associated with distinct types of defaunation of mammal and bird species, and are therefore likely to have distinct implications for animal-mediated interactions and processes, ecosystem functions, and conservation of tropical forests. Addressing major gaps in our empirical understanding of defaunation effects-e.g., hunting impacts on smaller-bodied mammals and birds, and responses of species in southeast Asian forests-is key to better understanding, predicting, and mitigating the impacts of this pervasive global threat.

The newly described Arunachal macaque Macaca munzala occurs largely in sub-tropical to temperate environments at elevations of c. 1,800-3,000 m in Arunachal Pradesh, northeastern India. We studied its over-wintering strategy by comparing the diet, ranging, and behavior of a troop of 24 individuals during winter and spring (December 2005 to May 2006) through instantaneous scan sampling (3,002 records, 448 scans, 112 hr of observation). We also monitored the phenology of food plants. The macaques spent more time (41-66%) feeding in the winter than in spring (33-51%), whereas time spent moving and resting was greater in spring. The diet composed largely of plants, with animal matter being eaten rarely. The number of plant species in the diet increased from 18 to 25 whereas food types rose from 18 to 36 from winter to spring, respectively. Although only two species formed 75% of the winter diet, seven species comprised this proportion in spring. Availability of fruits and young leaves increased in spring; the troop moved more and utilized a larger part of its range during this time. Seasonal changes in behavior could be explained by the scarcity of food and the costs of thermoregulation in winter. Our study suggests that the Arunachal macaque inhabits a highly seasonal environment and has an over-wintering strategy that includes subsisting on a high-fiber diet by increasing the time spent feeding, and minimizing energy expenditure by reducing the time spent moving.

Lockdowns intended to control the COVID-19 pandemic resulted in major socioeconomic upheavals across the world. While there were numerous reports of these lockdowns benefiting wildlife by reducing human movement and habitat disturbance, increased hunting during these lockdowns emerged as a conservation concern, particular in tropical Asia and Africa. We used online interviews with key informants including wildlife researchers, enforcement staff and NGO employees (N=99), and media reports (N=98), to examine the impacts of COVID-19 lockdown in India (March-May 2020) on wildlife hunting across the country. We asked whether and how hunting patterns changed during the lockdown, and explored socioeconomic and institutional factors underlying these changes. Over half the interviewees spread over 43 administrative districts perceived hunting (mammals, in particular) to have increased during the lockdown relative to a pre-lockdown reference period. Interviewees identified household consumption (53 percent of respondents) and sport and recreation (34 percent) as main motivations for hunting during the lockdown, and logistical challenges for enforcement (36 percent), disruption of food supply (32 percent), and need for recreational opportunities (32 percent) as key factors associated with hunting during this period. These insights were corroborated by statements by experts extracted from media articles. Collectively, our findings suggest that the COVID-19 lockdown potentially increased hunting across much of India, and emphasize the role of livelihood and food security in mitigating threats to wildlife during such periods of acute socioeconomic perturbation.

Armed conflicts are a pervasive global threat, but their implications for wildlife conservation remain unclear. Using a 30-year spatial dataset of armed conflicts in conjunction with species range maps, we found that conflicts during 1989-2018 occurred within at least 4291 (78%) and 9056 (85%) terrestrial mammal and bird species ranges, respectively. For 4% overall and 5-7% of threatened species, conflicts within ranges have been both widespread (≥50% of range) and frequent (≥15 years). Further, an examination of International Union for Conservation of Nature Red List assessments revealed that ranges overlap with armed conflicts is associated with declining population trends of threatened species and distinct species threat portfolios in which hunting and habitat loss and degradation are more prominent. Our findings call for greater recognition and understanding of direct and indirect threats from armed conflicts in species conservation assessments and underscore the importance of addressing conflict resiliency in conservation plans for a wide suite of species.