Incorporating human dimensions is associated with better wildlife translocation outcomes

The study addresses why some wildlife translocation efforts succeed while others fail, focusing on the role of human dimensions in planning and outcomes. While past research emphasized biological and ecological drivers (e.g., climate suitability, site quality, source population, number released), conservation increasingly occurs in shared human–wildlife landscapes where coexistence is crucial. The authors test whether explicitly setting human dimension objectives (social, political, psychological, economic, cultural) in translocation planning is associated with improved wildlife population outcomes. They also examine what factors predict inclusion of human dimension objectives, hypothesizing higher inclusion for wider-ranging taxa (mammals, birds), when threats are human-attributed, when there is a local history of human–wildlife conflict, and when local stakeholders are actively involved. They further predict increasing inclusion over time following broader conservation guidance (e.g., IUCN Guidelines 2013).

Prior studies on translocation success have focused largely on biophysical factors such as climate suitability, site quality, origin of source populations, and release numbers. Simultaneously, a growing body of work underscores human dimensions as integral to conservation outcomes because most wildlife threats are human-caused. Human dimensions have informed translocation designs across fish, mammals, birds, reptiles, and amphibians, including strategies like resource provisioning to reduce conflict, education and media campaigns, economic incentives for landowners, and enforcement against illegal trade. The IUCN Guidelines for Reintroductions and Other Conservation Translocations recommend integrating human dimensions throughout planning and evaluation. Nonetheless, conservation projects often omit these factors due to resource constraints, institutional legacies, and limited interdisciplinary collaboration. Calls for community-based, bottom-up approaches and integration of local and Indigenous knowledge reflect a broader shift toward socioecological frameworks, yet evidence linking human-dimension planning to translocation success has been limited and not comprehensively evaluated prior to this synthesis.

Dataset: 305 vertebrate wildlife translocation case studies from seven IUCN Global Re-introduction Perspectives volumes (2008–2021), covering translocations from 1922–2018 and 268 unique species across continents. Case study structure was standardized (Introduction, Goals, Success Indicators, Project Summary, Major Difficulties Faced, Major Lessons Learned, Reason(s) for Success). Data extraction: For each case, coders assessed whether human dimensions were explicitly included as objectives (binary yes/no) based on presence in Goals or Success Indicators. Human-dimension objectives were categorized into six strategies: education, engaging locals, economic benefits, increasing social tolerance, enforcing regulations, and cultural benefits. Additional recorded variables: project location; start year; stakeholder groups involved (government, academic, zoo, non-profit, local community, private landowner, private company); IUCN-classified threats (direct human threats such as development, agriculture, energy and mining, transport, biological resource use, disturbance, systems modification; indirect human threats such as invasive species/diseases, pollution, climate/severe weather); and whether there was a local history of human–wildlife conflict. Outcome classification: Population-level outcome was coded as positive (widespread survival, reproduction, and/or population growth) or negative (widespread mortality or extinction), using the Project Summary and Reason(s) for Success sections, to reduce variability across taxa and project durations. Coding process: Coauthors independently reviewed an initial subset to develop a consistent classification framework, then applied it across all cases with group discussion to resolve ambiguities. Statistical analysis: Logistic regression models in R 4.0.2 tested (1) association between inclusion of human-dimension objectives and positive outcomes (response: positive/negative; predictors: inclusion of human-dimension objectives, project time length, taxon); (2) predictors of including human-dimension objectives (response: inclusion yes/no; predictors: taxon, IUCN threats, local conflict history, stakeholder groups; with Tukey post-hoc pairwise comparisons); (3) a global model assessing relative importance of significant predictors (taxon, local conflict, involvement of local community groups, presence of direct human threats). Temporal trends were evaluated with univariate logistic regressions using start year and a binary pre/post-2014 indicator for the 2013 IUCN Guidelines. Significance was evaluated at alpha 0.05, and figures generated with ggplot2.

- Of 305 case studies, 42% (n=127) included human-dimension objectives in Goals or Success Indicators; 57% (n=173) mentioned human dimensions in Lessons Learned or Major Difficulties, including 76 cases that did not have human-dimension objectives in planning. - Most projects reported positive outcomes (n=272); 11% (n=33) reported negative outcomes. - Inclusion of human-dimension objectives was associated with a significantly higher probability of a positive population outcome (reported estimates: 0.94; 95% CI 0.88–0.97 with objectives vs 1.02; 95% CI 0.07–2.10 without; p<0.01). Project time length and taxon were not significant predictors of outcome (p>0.05). - Six strategies for human-dimension objectives were identified; their frequency: education (n=111), engaging locals (n=96), economic benefits (n=41), increasing social tolerance (n=32), enforcement (n=19), cultural benefits (n=9). - Inclusion of human-dimension objectives varied by taxon, threats, stakeholders, and conflict history. Mammal (0.53; 95% CI 0.44–0.62) and bird (0.41; 95% CI 0.31–0.53) translocations had higher predicted probabilities of including human-dimension objectives than amphibians (0.15; 95% CI 0.06–0.34) (p<0.01 and p=0.01, respectively). Mammals also exceeded fish (0.33; 95% CI 0.20–0.48; p=0.02). - Reported local history of conflict increased the predicted probability of including human-dimension objectives to 0.62 (95% CI 0.50–0.73) vs 0.36 (95% CI 0.30–0.42) without conflict (p<0.01). - Stakeholder involvement: projects involving local communities (0.63; 95% CI 0.50–0.73) and private landowners (0.68; 95% CI 0.53–0.80) were more likely to include human-dimension objectives than those involving academics (0.39), zoos (0.35), government (0.42), nonprofits (0.47), or private companies (0.50) (p<0.05). Projects with local community involvement had higher predicted positive outcomes (0.97; 95% CI 0.88–0.99) than those involving academics, nonprofits (0.87; 95% CI 0.81–0.91), or private companies (0.83; 95% CI 0.63–0.93). - Threat context: species threatened by transportation/service corridors, energy/mining, agriculture/aquaculture, and biological resource use had the highest predicted probabilities of including human-dimension objectives; lowest were for climate change, invasive species, and natural system modifications. - Global model: mammal taxa, local conflict history, and involvement of local community groups remained significant predictors of including human-dimension objectives; fish taxa and direct human threat were not significant when considered with other variables. - Temporal trend: estimated probability of including human-dimension objectives increased from 0.20 (95% CI 0.09–0.40) in 1960 to 0.50 (95% CI 0.40–0.60) in 2018 (p=0.05). No significant change was detected immediately following the 2013 IUCN Guidelines (pre n=248; post n=38; p>0.05).

The analysis quantifies a strong association between planning for human dimensions and improved wildlife population outcomes in translocations, suggesting about a 10% higher probability of success when human-dimension objectives are included. Effective strategies include education, engaging local stakeholders, economic incentives, social tolerance initiatives, cultural benefits, and enforcement, with stakeholder engagement—especially local communities and private landowners—linked to both greater inclusion of human-dimension objectives and higher success probabilities. The study also reveals taxonomic and contextual biases: mammals and birds are more likely to have human-dimension planning than amphibians, potentially due to greater conflict potential and perceived charisma. While regulations and economic incentives can aid conservation, they can also produce unintended social harms (e.g., militarized enforcement, inequitable benefit sharing) that may undermine outcomes, underscoring the need for careful, interdisciplinary design. Despite growing recognition and guidance, many projects still do not explicitly integrate human dimensions, though inclusion has increased over time. Integrating socioecological tools and participatory approaches can improve prediction of conflict risk, habitat suitability, and community buy-in, enhancing translocation success and long-term sustainability.

This study provides comparative evidence that explicitly incorporating human-dimension objectives into wildlife translocation planning is associated with improved population outcomes. It identifies key predictors for inclusion—mammal/bird taxa, local conflict history, and engagement of local communities and landowners—and documents increasing adoption over time. The findings support conservation strategies that integrate social science, stakeholder engagement, and context-specific human-dimension interventions alongside biological and environmental planning. Future work should disentangle the relative effectiveness of specific human-dimension strategies, evaluate broader measures of success beyond population outcomes, and further develop socioecological planning tools to reduce conflict and enhance equitable, durable conservation benefits.

Outcomes were classified in a binary manner focused on population-level results (survival, reproduction, growth vs mortality/extinction), which omits other potential success dimensions (e.g., learning, stakeholder support). The IUCN case studies are self-reported summaries that may lack detail and are subject to publication and reporting bias, with successful translocations more likely to be reported than failures—reflected in a low observed failure rate (11%). Smaller organizations and unsuccessful projects may be underrepresented, limiting generalizability to all attempted translocations. Additionally, only objectives explicitly stated in Goals or Success Indicators counted as inclusion of human dimensions, potentially underestimating informal or unreported human-dimension activities.