Human-carnivore conflict mitigation on ranchlands in the western United States and eastern Colombia

Abstract

Conflict between large carnivores and ranching livelihoods is a persistent challenge for carnivore conservation and management. Shifting societal views of large carnivore management at the end of the 20th century led to population recovery and, in some cases, reintroduction to their former range. Working lands, productive areas encompassing a matrix of human land use and natural land cover, are an important part of carnivore range as they provide vital habitat and connectivity between protected areas. However, large carnivores can have direct and indirect impacts to humans and human livelihoods on working lands through livestock depredation, increased labor to mitigate depredations, and in some cases risk to human safety. In the Western United States, the reintroduction of gray wolves (Canis lupus) and the recolonization of grizzly bears (Ursus arctos) are hailed as species recovery success stories but have been met with resistance from rural ranching communities. Wildlife managers, researchers, and other entities throughout the region seek to reduce livestock producers' burden of living with large carnivores while ensuring sustainable populations. On the plains of Eastern Colombia, jaguars (Panthera onca) are recolonizing former range after being nearly extirpated following centuries of conflict over livestock and the pelt trade in the mid-20th century. In Colombia, jaguars depredate livestock, but there is little government support for the implementation of prevention tools and no compensation for losses, leaving non-governmental organizations as the sole implementers of conflict mitigation. In both contexts, wildlife managers require tools and strategies to address livelihood impacts and incentivize human-carnivore coexistence. Development and evaluation of these methods is important to ensure that limited resources are being utilized effectively. In this dissertation, I examine human-carnivore conflict in the Western United States and Eastern Colombia through three lenses: population trends related to conservation interventions for large carnivores; evaluation of non-lethal conflict reduction tools; and the human dimensions of non-lethal mitigation. In Chapter 1, I examine jaguar population trends on a working ranch and wildlife tourism destination in Casanare, Colombia. We integrated nine years of camera trap data and tourist photos to estimate jaguar survival, abundance, and probability of tourist sightings through a Barker Robust Design mark-recapture model. We then used spatially explicit capture-recapture to estimate jaguar density and compare it to a 2014 estimate. We found that abundance increased from 5 ± 0.26 individuals in 2014 to 28 ± 2.7 in 2022, and density increased from 1.88 ± 0.87 per 100 km2 in 2014 to 3.80 ± 1.08 jaguars per 100 km2 in 2022. We estimated survival rate of 78 ± 0.08% for males and 80 ± 0.07% for females. The probability of a tourist viewing a jaguar increased from 0 ± 0.11% in 2014 to 40 ± 0.18% in 2020 before the Covid-19 pandemic. We provide the first robust estimates of jaguar survival and abundance on working lands. Our findings highlight the importance of productive lands for jaguar conservation and suggest that a tourism destination and working ranch can host an abundant population of jaguars when accompanied by conservation agreements and conflict interventions. Our analytical model that combines conventional data collection with tourist sightings can be applied to other species that are observed during tourism activities. In chapter 2, I evaluate the effectiveness of diversionary feeding—providing food caches to divert predators away from preying on livestock—to reduce depredations by reintroduced Mexican wolves in the US states of New Mexico and Arizona. We used data from the Mexican wolf recovery program from 2014-2021 in a Bayesian hierarchical model to evaluate whether diversionary feeding reduced livestock depredations by wolf packs and what factors correlated with depredations. Our model accounted for the non-detection of depredation events, given that some depredations are unencountered or unreported on extensive rangelands. We found that diversionary feeding reduced depredations on average by 0.78 ± 0.03 depredations (43.9%) per pack per year. Prey density was negatively correlated to depredations before diversionary feeding. Minimum pack size and annual livestock density were negatively correlated with depredations after diversionary feeding, while prey density was positively correlated. We estimated a mean of 63 ± 5.4% of depredations were detected with high variation between packs (40.4 ± 7.9 % – 74.0 ± 5.3%). Because detections were only two-thirds of model-estimated depredations in our study, our model could improve compensation and targeting of nonlethal tools to mitigate the financial burden of co-occurrence with wolves by elucidating factors that lead to lower detection and adjusting livestock loss compensation multipliers. Our results indicate diversionary feeding can reduce livestock depredations by wolves on large landscapes in the Western United States but is not a panacea for conflict reduction. In chapter 3, I examine the context of human tolerance for large carnivores before and after the implementation of electric fencing to reduce depredations by jaguars. Non-lethal mitigation is often implemented under the premise that ranchers' tolerance for large carnivores will increase once losses or reduced or eliminated. However, deep-rooted psychological and cultural factors can be equally, if not more, important for predicting tolerance. We conducted structured interviews in four communities in the Colombian Llanos to characterize conflict, identify predictors of retaliatory killings of jaguars, and evaluate the impact of a fencing intervention to increase tolerance. The social psychological variables from the theory of planned behavior were a better predictor of intention to kill a jaguar than past and expected livestock losses. The intervention did not increase tolerance, likely because self-selection bias led to a treatment group that was tolerant pre-intervention. Sixty percent of respondents reported moderate to severe livestock losses during year 1, highlighting the urgent need to identify broader mitigation strategies for livestock depredation. Positive attitudes and normative support in favor of retaliatory killings were pervasive, while 24% of respondents were intolerant—having positive attitudes of and intent to retaliate against a jaguar following the next livestock depredation. Our results suggest that a strategy focused only on reducing depredation is unlikely to reduce retaliatory killings, as losses are not the only driver of retaliation. The pervasiveness of livestock losses and support for retaliatory killings demonstrate a need for immediate action to reduce livelihood impacts and consider alternative, bottom-up approaches to conflict mitigation in the area. My research indicates that wildlife tourism and diversionary feeding are two strategies that can mitigate the livelihood impacts of large carnivore presence. Wildlife tourism on Colombian ranchlands provides tangible economic benefits to landowners to conserve jaguars, other wildlife, and their habitat. We observed an important population increase for the locally threatened jaguar, and conserving jaguar habitat likely has reverberating benefits for ecosystem services and other wildlife through prey hunting prohibitions. Further work is necessary, however, to understand the distribution of costs and benefits from jaguar tourism and population growth in the surrounding community to ensure equitable conservation outcomes. In addition, diversionary feeding proved to be an effective tool to reduce depredations by Mexican wolves in the Southwestern U.S. The integration of non-detection of depredation events in our analysis is an important contribution to carnivore management because it can elucidate uncompensated livelihood impacts which aggravate intolerance for carnivores. This tool could be applied to other populations of carnivores to mitigate losses and may be more easily deployed than some deterrents. Findings from my third chapter reinforce the importance of understanding the human dimensions of human-carnivore conflict prior to implementing conflict reduction strategies. Interventions based solely on livestock losses may be unsuccessful at reducing retaliatory killings if losses are not the only driver of intolerance of carnivores. Ultimately, human-carnivore conflicts and interventions to prevent them are nested with unique social, cultural, ecological, political, and economic context. The failure of interventions to recognize how carnivore behavior interacts with local human contexts may ultimately exacerbate conflict and lead to counterproductive mitigation strategies.