COMMUNITY INTERVENTIONS TO REDUCE HUMAN-BLACK BEAR CONFLICT IN COLORADO

Abstract

Human-wildlife conflict is a global conservation challenge and emerges when wildlife pose actual or perceived threat to human interests or needs, leading to disagreements between groups of people and negative impacts on people and/or wildlife. Human-wildlife conflict intersects other global change threats; land transformation for agriculture and urban development is expected to increase human-wildlife overlap in the 21st century and climate change can intensify conflict by exacerbating resource scarcity and forcing people and wildlife to share increasingly crowded spaces. Conflict also particularly affects vulnerable human communities, such as low-income rural communities, making it both a pressing conservation and a social justice issue. Among species affected by conflict with people, large carnivores are particularly vulnerable. Specifically, conflicts between people and American black bears (Ursus americanus, hereafter "black bears", or "bears") occur throughout their range and include threat to human safety, depredation by bears of pets or livestock, or damage to property or agricultural resources. Encounters also lead to bear mortality through management euthanizations and accidental collisions with vehicles, which can have demographic consequences on bear populations. A common driver of conflict is the greater availability of anthropogenic food sources at the urban-wildlife interface, particularly garbage. Another important factor mediating the probability of conflict is the availability of natural foods, where late season frosts and drought can limit natural foraging options for black bears and exacerbate conflict. To mitigate the consequences of conflict on human endeavors and bear populations, solutions that foster coexistence are needed. Common management responses include capturing and relocating individual bears, euthanizing or permitting hunters to harvest individual bears, and education through site visits, brochures, media, and workshops. However, the effectiveness of these tools in reducing long-term risk of conflict is somewhat limited. Given the importance of anthropogenic food sources in driving conflict, and that the success of coexistence tools often hinges on the involvement of stakeholders, proactive approaches led with or by communities to remove anthropogenic attractants are promising. In Chapter 1, I evaluated the behavioral response of black bears to an experimental change in residential waste management in Durango, Colorado. Using location data from collared black bears, I modeled resource selection and movement in response to areas that had received bear-resistant garbage containers compared to those that did not. Over the four years following the distribution of bear-resistant garbage containers, the probability of use by a bear of the sites where containers had been distributed decreased from ~12% in 2013 to ~8% in 2016 (a decline of ~30%). In the same period, bear activity slightly increased where residents continued to use regular containers (11% in 2013 and 12% in 2016), suggesting bear-resistant garbage containers were effective at de-valuing trash as an attractant and at altering the economics of foraging decision-making. This avoidance response increased over subsequent years, potentially suggesting that bears were learning from the management intervention. Bear movement rates, however, were not notably affected by the garbage reduction. Our findings highlight the importance of reducing the availability of anthropogenic attractants for changing bear behavior and reducing risk of urban human-bear conflict, and that these responses can strengthen over time as bears learn from the management intervention. In Chapter 2, I characterized spatio-temporal patterns in human-bear conflict in Colorado and quantitatively evaluated a statewide community program that provides Colorado communities with financial resources to support efforts to reduce human-bear conflicts and foster innovative solutions to human-bear conflict. I utilized a statewide database of citizen reports of human-bear conflict to Colorado Parks and Wildlife between 2019 and 2025. I identified patterns in conflict reports, including temporal trends, spatial hotspots, and sources of conflict. I also evaluated the program by assessing if it targeted areas with high levels of conflict risk and if interventions resulted in reductions in risk of conflict. Statewide human-bear conflict reports increased in the last 40 years but were similar to estimates from the early 2000s. They were primarily related to human development and caused by residential attractants such as garbage and other food sources (e.g., pet food, barbeque grills, bird feeders, freezers, ornamental fruit trees, and home gardens). Natural food conditions influenced rates of conflict at both statewide and local scales. The community program effectively targeted high-risk locations. Community-led interventions focused on securing garbage, outside food sources, and livestock in bear-resistant infrastructure or with electric fencing were effective at reducing the probability of conflict, especially garbage-related conflicts. However, the effectiveness of funding interacted with whether a project area had received large-scale bear-proofing efforts prior to the grant. Conflict risk decreased by 14.5% after treatment in communities implementing new conflict-reduction efforts, but increased by 15.2% in several communities that had previously deployed significant investment in reducing attractants, possibly due to a lessened effectiveness of continued actions relative to previous efforts, a failure of previously distributed cans, or an increase in reporting rates. These findings support the continuation of attractant-reduction efforts led by communities and highlight the importance to maintain infrastructure and enforcement efforts over time. In Chapter 3, I adopted a complementary approach to learn from the statewide community program and investigated policy designs used by Colorado communities to address human-bear conflict. I catalogued policy tools used by communities; assessing the feasibility, effectiveness, fairness, and long-term effects of different tools and identifying conditions that facilitate or challenge their implementation and effectiveness, as perceived by those implementing policies. I followed a qualitative methodology based on a mix of document review, semi-structured interviews, and fieldwork observations to collect data, then used a modified grounded theory approach to inform emergent findings with theoretical concepts from policy design. Interviewees described how a combination of regularly updated ordinances, escalating fine structures, capacity for proactive enforcement and support for residents were the most effective way to address human-bear conflicts in communities in the long term. They also presented hortatory tools as a more feasible first step in addressing conflicts, despite its insufficiency as a sole tool and its short term effects. Learning tools were also common, especially when initiating efforts in a community. In addition, participants described conditions that could act as catalysts or barriers to tool implementation and effectiveness. High respect for government authority, strong sense of community engagement, and high economic resources in a community all facilitated the mode of action of ordinances, fines, and capacity. Avenues to trust and to collaboration between several actors also helped actions be successful. This work highlights the importance of designing synergic policy portfolios to address human-bear issues in communities and adapting them to local context. State and local policy could focus on more clearly delineating roles between collaborating institutions and support boundary organizations (e.g., non-profit organizations, point-of-contact agency positions) that help ground policies in local contexts and support collaboration and learning. My research highlights the important role of reducing attractants in developed areas, specifically garbage, to foster human-bear coexistence in mountain communities. Garbage was the main cause of human-black bear conflicts in Colorado, and community-led policies that reduced the availability of anthropogenic attractants were effective at reducing the risk of conflict. Communities that successfully addressed conflict combined a mix of policies: they enacted, updated and proactively enforced ordinances to regulate behaviors leading to the availability of attractants, and they built capacity to populations with subsidies and loans programs for bear-resistant infrastructure. Policies were implemented by a network of local government bodies, non-profit organizations, and businesses. To continue to mitigate human-bear conflict in developed areas, solutions should continue to address common attractants, maintain efforts over time, and be sensitive to local contexts.