Quantitative assessment of supplementary feeding as an adaptive conservation management strategy for red-billed choughs.
Lead Research Organisation:
University of Aberdeen
Department Name: Inst of Biological and Environmental Sci
Abstract
Successful conservation of wildlife populations requires effective management policies to be enacted by government and non-government agencies, thereby maintaining wildlife's intrinsic, cultural and economic benefits. One key paradigm is adaptive management, where i) scientific understanding of ecological and demographic drivers of population change is used to plan and implement management; ii) impacts on population ecology, demography and dynamics are quantified; iii) resulting evidence is used to plan subsequent management. However, such adaptive management is rarely enacted, not least because high-quality data quantifying short-term and longer-term impacts of initial management are rarely collected or rigorously analysed, eroding the evidence-base for future policy.
This project provides an outstanding multidisciplinary training opportunity for a PhD student to develop an exemplary adaptive management model for one of the UK's most endangered birds, the red-billed chough. The student will rigorously evaluate effects of a key management intervention, supplementary feeding, applied in a Scottish chough population of major conservation concern. They will work alongside government conservation agency staff involved in research, policy and operation, and stakeholders and academics, to use resulting evidence to decide future conservation policy. The project will thereby train a new scientist to drive science-policy convergence, advancing society's ability to conserve valued wildlife populations through adaptive management.
Provision of supplementary food is a key management tool for food-limited target populations. However, althoughvertebrate population dynamics are commonly constrained by low sub-adult and adult survival, supplementary feeding regimes typically focus instead on increasing breeding success. Despite its potential as a key management tool, few experimental or management interventions have fed sub-adults, or evaluated short-term effects on sub-adult survival. Further, such feeding could have profound longer-term effects by altering sub-adult dispersal, age at first breeding or subsequent reproduction. However, no studies have quantified such effects or hence evaluated overall effects of
supplementary feeding of sub-adults on population growth rate. Scotland's remaining chough population is limited to Islay and Colonsay and is of major conservation concern and socioeconomic
value due to eco-tourism, cultural significance and links to low-intensity pastoral agriculture. Scottish Natural Heritage (SNH), Scotland's statutory conservation agency, is obliged to undertake appropriate management action.
Analyses of high-quality demographic data for 1983-2009 showed that variation in chough population size largely reflects variation in sub-adult survival, and very high sub-adult mortality during 2007-2009 threatened population viability. SNH therefore funded a programme of supplementary feeding of sub-adult choughs and associated demographic monitoring. A subset of sub-adults on Islay were/will be fed daily during July-April 2010-2018, by Scottish Chough Study Group (SCSG). Detailed ring resighting and nest monitoring data have been collected to allow survival, dispersal and reproduction of fed and unfed individuals to be quantified.
The PhD student will use this truly remarkable multi-year dataset to comprehensively assess effects of supplementary feeding of sub-adults on demography and population growth rate using Before-During-Control-Impact (BDCI) analyses encompassing 1983-2019. They will work with SNH and SCSG (CASE and project partners) to use their results to decide future feeding policy in the wider context of habitat management enacted by the Scottish Rural Development Programme. They will thereby undertake excellent science to quantify effects of a novel form of supplementary feeding, and directly influence conservation policy and practice for a rare bird for which UK governments are responsible.
This project provides an outstanding multidisciplinary training opportunity for a PhD student to develop an exemplary adaptive management model for one of the UK's most endangered birds, the red-billed chough. The student will rigorously evaluate effects of a key management intervention, supplementary feeding, applied in a Scottish chough population of major conservation concern. They will work alongside government conservation agency staff involved in research, policy and operation, and stakeholders and academics, to use resulting evidence to decide future conservation policy. The project will thereby train a new scientist to drive science-policy convergence, advancing society's ability to conserve valued wildlife populations through adaptive management.
Provision of supplementary food is a key management tool for food-limited target populations. However, althoughvertebrate population dynamics are commonly constrained by low sub-adult and adult survival, supplementary feeding regimes typically focus instead on increasing breeding success. Despite its potential as a key management tool, few experimental or management interventions have fed sub-adults, or evaluated short-term effects on sub-adult survival. Further, such feeding could have profound longer-term effects by altering sub-adult dispersal, age at first breeding or subsequent reproduction. However, no studies have quantified such effects or hence evaluated overall effects of
supplementary feeding of sub-adults on population growth rate. Scotland's remaining chough population is limited to Islay and Colonsay and is of major conservation concern and socioeconomic
value due to eco-tourism, cultural significance and links to low-intensity pastoral agriculture. Scottish Natural Heritage (SNH), Scotland's statutory conservation agency, is obliged to undertake appropriate management action.
Analyses of high-quality demographic data for 1983-2009 showed that variation in chough population size largely reflects variation in sub-adult survival, and very high sub-adult mortality during 2007-2009 threatened population viability. SNH therefore funded a programme of supplementary feeding of sub-adult choughs and associated demographic monitoring. A subset of sub-adults on Islay were/will be fed daily during July-April 2010-2018, by Scottish Chough Study Group (SCSG). Detailed ring resighting and nest monitoring data have been collected to allow survival, dispersal and reproduction of fed and unfed individuals to be quantified.
The PhD student will use this truly remarkable multi-year dataset to comprehensively assess effects of supplementary feeding of sub-adults on demography and population growth rate using Before-During-Control-Impact (BDCI) analyses encompassing 1983-2019. They will work with SNH and SCSG (CASE and project partners) to use their results to decide future feeding policy in the wider context of habitat management enacted by the Scottish Rural Development Programme. They will thereby undertake excellent science to quantify effects of a novel form of supplementary feeding, and directly influence conservation policy and practice for a rare bird for which UK governments are responsible.
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| NE/P009719/1 | 01/10/2017 | 30/06/2022 | |||
| 1970082 | Studentship | NE/P009719/1 | 01/10/2017 | 31/12/2021 | Sarah Fenn |
| Description | Supplementary feeding is a widely used tool to aid conservation of threatened and declining populations, because it is expected to rapidly increase survival and/or breeding success. However, there is conflicting evidence regarding the efficacy of supplementary feeding, with some studies suggesting negligible impacts on target populations, or even unintentional negative effects on individuals and populations. Therefore, it is vital to thoroughly assess the individual and population level impacts of targeted conservation interventions such as supplementary feeding for threatened populations, and predict the expected consequences for population recovery. The Scottish population of red-billed choughs (Pyrrhocorax pyrrhocorax) is threatened with extinction, largely due to an unsustainable decline in juvenile survival which was primarily driven by low food availability in late summer. To prevent further population declines, a multi-year (2010-18) emergency supplementary feeding programme was funded on the isle of Islay, Scotland, to provide young birds with an additional food source, with the aim of increasing juvenile survival. Using resightings of individually identifiable choughs at feeding sites and in other areas on Islay, we found that supplementary feeding successfully increased juvenile survival; survival of juveniles that used supplementary food was greater than those that did not. Further, by comparing survival rates of adult choughs that lived in areas with or without supplementary feeding, and comparing these to survival rates from before the supplementary feeding began, we found that the feeding programme also had substantial positive impacts on adult survival, as well as a moderate positive impact on breeding success, which themselves contributed substantially towards achieving the short-term conservation objective of population stability. However, the supplementary feeding programme never intended to target adult choughs, and so highlights the importance of explicitly evaluating potential unintended impacts of conservation management on conservation success. Overall, results thus far indicate that supplementary feeding substantially increased short-term population persistence of the Scottish chough population, and has therefore been a positive conservation intervention. |
| Exploitation Route | These results will be used to bodies making decisions on future conservation policy and conservation management for red-billed choughs in Scotland. More generally, however, these results may prove useful to conservation practitioners, by highlighting the need to explicitly consider unintentional impacts of targeted interventions, and how such impacts may affect assessment of short-term efficacy. |
| Sectors | Environment |
| Description | Findings have been used as part of a commissioned report for Scottish Natural Heritage entitled "Conservation strategy for red-billed choughs in Scotland: Assessment of the impact of supplementary feeding and evaluation of future management strategies". This report provides an assessment of the effects of the supplementary feeding, evaluates different ecological and genetic management strategies to and support long-term population persistence. Based on this, the report then provides recommendations for key next steps in Scottish chough conservation policy and management strategy. |
| First Year Of Impact | 2020 |
| Sector | Environment |
| Impact Types | Policy & public services |
| Description | Results used as part of commissioned report for Scottish Natural Herritage on conservation strategy for red-billed choughs in Scotland |
| Geographic Reach | Local/Municipal/Regional |
| Policy Influence Type | Contribution to a national consultation/review |
| Description | Public engagement event on threatened Scottish species |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Public/other audiences |
| Results and Impact | Participated in a public engagement event which aimed to highlight threatened species in Scotland. We dicussed the decline of chough in Scotland with members of the public, and described current research on how effective different management strategies, such as supplementary feeding, were for their conservation. A small survey of attendees showed that there was a very high level of interest in chough conservation, and most agreed or strongly agreed that interventions to support chough conservation should be continued/further implemented. |
| Year(s) Of Engagement Activity | 2019 |
| Description | Talk to undergraduate students |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Undergraduate students |
| Results and Impact | Presentation for undergraduate students interested in conservation issues and practice to demonstrate a case of evidence driven conservation management and policy. |
| Year(s) Of Engagement Activity | 2019,2020 |