Introduction

One of Wild Animal Initiative’s foundational questions is: “what can we do to improve the welfare of wild animals?” (Wild Animal Initiative 2019). Currently, we are reviewing and summarizing relevant literature from restoration and conservation ecology, as these fields often evaluate the impacts and effectiveness of wildlife interventions. Even if conservation ecologists are not necessarily value-aligned with animal welfare advocates (e.g. diversity is good - Soulé 1985, Driscoll and Watson 2019; but see Dubois and Fraser 2013 and Beausoleil et al. 2018), impact assessments from conservation are still useful to wild animal welfare (Rowe 2019). Reviews of conservation evidence increase our understanding of the outcomes of interventions in nature and enables us to apply these interventions to welfare causes.

One such conservation database is the Conservation Evidence Project, which has evaluated over 5,400 conservation interventions and compiled synopses on what works and what doesn’t to achieve certain conservation goals. The synopses summarize scientific evidence relevant to conservation objectives and assess the effectiveness of interventions based on the available evidence, including if no evidence has been found. The Conservation Evidence Project also publishes an annual summary, What Works in Conservation (Sutherland et al. 2018).

These synopses combine the results of research projects that carried out the intervention as part of the study design and quantitatively monitored the effects of the intervention. Reviews and meta-analyses are also included. However, predictive modelling or correlative studies (e.g. surveys of species distributions in areas with long-standing management histories) are not. The advantage to this approach is that the synopses are based on direct, causal relationships between the intervention and the observed conservation outcomes (Sutherland et al. 2018). The disadvantage is that a large body of possible evidence is excluded, since observational studies provide reliable data that confirm ecological phenomenon in real-world settings and complement causative experiments (Sagarin and Pauchard 2010). The Conservation Evidence Project acknowledges that their database is just one tool in the decision-making process, and encourages researchers to consult more comprehensive systematic reviews, such as those compiled by the Centre for Evidence-Based Conservation and the Collaboration for Environmental Evidence (Sutherland et al. 2018).

To integrate the Conservation Evidence database with wild animal welfare, we highlight the interventions which overtly change the lives of animals, such as those which alter movement, feeding, or reproductive behavior or control competition and predation. Most of the summarized research measures the effects on species diversity, abundance, or population size. Reproductive success, body condition, or behavior are evaluated less frequently, which appears to reflect a limitation within the conservation and restoration literature (Cooke and Suski 2008, Cooke et al. 2013). Research on wild animal welfare can address this knowledge gap by targeting interventions to these understudied areas (Dawkins 2008, Beausoleil et al. 2018).

We also re-evaluate the interventions from the Conservation Evidence database from a welfare-oriented perspective to illustrate how conservation evidence can inform predictions of the primary and non-target effects on welfare. Target effects are the direct effect on the welfare of the focal species or individuals and non-target effects refer to the welfare impacts on other animals in the ecosystem. The outcomes on conservation targets are given in the online synopses, which are linked to when available. We also incorporate the conservation evidence into Wild Animal Initiative’s interventions classification system (forthcoming in 2019) to further build our capacity to conduct welfare interventions in the future. Overall, we find that conservationists and welfare advocates may emphasize different potential effects and trade-offs when evaluating environmental problems, yet the different approaches may or may not, in practice, change the intervention actions.

Highlighted Interventions