Are birds enhancing or diminishing delivery of nature-based solutions at the food – climate change nexus in forest – agricultural landscapes of the rural tropics?

Overview

Forest Landscape Restoration (FLR) is seen as central to achieving global ecosystem restoration ambitions and to reverse ecological impacts of land degradation and enhance human wellbeing (Mansourian & Vallauri, 2014). FLR is meant to restore multi-functional landscapes for multiple benefits to different stakeholders. In theory, this ambition aligns well with the Bonn challenge and other targets that are used as a roadmap for global restoration progress, within and beyond the UN Decade on Ecosystem Restoration.

Tree centred nature-based solutions may include the management of crop production landscapes for multi-functionality and resilience to environmental shocks (Rockström et al., 2017), for example through agro-ecology or agroforestry. Millions of people in tropical rural landscapes rely on agroforestry farming and recognise the values of trees and native tree species (Nyong et al., 2020). Trees on and around farms regulate ecosystem processes relevant for crops, including water regulation and prevention of soil erosion (Hurni et al., 2015), microclimate buffering, and maintenance of populations of pollinator and natural pest control species. Yet, trees can also act as a source for human–wildlife conflicts including crop damage through wildlife acting as pests (König et al., 2020). Trees may negatively impact yields, yet evidence is limited for humid areas and overall inconclusive with yield changes due to competition with trees depending on tree species, tree maturity and crop type (Ndoli et al., 2017)

Using FLR to improve outcomes for ecological and human wellbeing in landscapes used for agriculture is a challenge that requires careful consideration of trade-offs and synergies that emerge when the natural and social components of the system interact. And practitioners agree that the choice of trees for planting on and around farms has to be considered carefully. Importantly, there is limited understanding of the ecological network impacts of tree restoration and how these may play out to affect services and disservices provided by wildlife to wellbeing or local communities. In other words: If we restore trees in the landscape, does this alter movements of wildlife at higher trophic levels, and if so, does it alter the distribution of risks in crop damage or of potential for pollination and natural pest control.

In this PhD, the candidate will focus on the interconnections between birds, crops and habitats (configuration, management and quality) in forest-agricultural systems in East Africa. They will study the role of birds in shaping crop yield outcomes through their impacts on crops (acting as pests), insect and other pests (acting as natural pest controls), focussing on key food and cash crops grown by rural communities for food and livelihood securities. The candidate will implement fieldwork in a case study landscape in Tanzania to acquire in depth, mechanistic understanding on: (i) habitat dependencies of birds in relationship to trees and farms (configuration of trees and crops, quality and type of trees and crops) using observational data and spatially explicit modelling, and (ii) interactions with crops using experiments.

The key objectives include:
• Objective 1: Analyse tree cover dependency, interactions with different crop types and distribution of focal bird species in forest-agricultural landscapes in East Africa.
• Objective 2: Model the movements of focal bird species through the forest-agricultural landscape in the north of the Kilombero Valley (Agrisys Tanzania case study landscape) as function of landscape configuration, crop type and tree species
• Objective 3: Analyse trade-offs and synergies resulting from forest conservation and tree restoration with regards to carbon stocks in trees, bird biodiversity, and bird regulated services and disservices to crops.
• Objective 4: Work with local communities to understand perceptions of ‘good’ versus ‘bad’ bird species and how tree restoration may need to be implemented and managed to avoid negative outcomes for human wellbeing.

Methodology

The student would be hosted t the Modelling, Evidence and Policy RG at Newcastle University and interact closely with the research group of Prof Willis at Newcastle University.

Objective 1 tasks: Focal species include threatened species, and known and suspected pests, pest controls, and pollinators. Traits data are compiled. Species and their habitat use in different landscape will be compiled from existing bird assessments using access to researcher networks provided by MEP group member Dr Pfeifer. These will be complemented by IUCN data.

Objective 2 tasks: The candidate will use spatially explicit modelling frameworks (Individual-Based Models, CAR, INLA) to analyse and predict movements of focal birds and their interactions with crops and other habitat types in the case study. This will build on existing bird survey data and camera trap captures of birds in crop and non-crop habitats implemented in 2019 and 2020. The candidate will add observations and experiments and collection of fecal samples for DNA barcoding.

Objective 3 tasks: The candidate will use the systems model developed by Agrisys Tanzania and calibrated for the case study with field data. They will use it with outcomes from Objective 2 to map synergies and trade-offs resulting from forest conservation and tree restoration with regards to carbon stocks in trees, bird biodiversity, and bird regulated services and disservices to crops.

Objective 4 tasks: The candidate will work with IUCN, Reforest Africa and local farmers (surveys, focus groups) to identify perceptions of birds and the positive and negative values associated with these and to discuss how tree restoration interventions may interact with these values to shape farmer wellbeing. Workshops will be used to discuss evidence from field and models together with perceptions and suggestions of mitigation or adaptation measures to co-develop restoration plans.

Project Timeline

Year 1

Compile existing data. Sending out data requests through researcher networks in East Africa. Implement evidence synthesis -> Objective 1. Plan sampling design for observational studies and field experiments in case study landscape. Apply for research permits.

Year 2

Implement fieldwork in case study landscape. Process bird data and link to extensive ecological and biophysical data collected for the case study landscape by AgrisysTanzania. Adapt and calibrate individual based models (e.g. in – house scripts and RangeShifter (RangeShifter) -> Objective 2

Year 3

Run individual based models for current landscape configuration and management and scenarios of changes in crop type (e.g. planned expansion of sugarcane farming) and changes in tree cover and tree – crop configuration (planned restoration interventions). -> Objectives 2 and 3

Year 3.5

Implement surveys, 1 knowledge exchange and 1 scenario workshop in the case study, working with small-holder and industry farmers, both conservation partners and Sokoine University of Agriculture (Dr Deo Shirima). -> Objective 4

Training
& Skills

The successful candidate will receive training in advanced spatial analyses, fieldwork design and implementation in rural tropical countries and socio-ecological methods and frameworks used in conservation science. The candidate will be placed in the Modelling, Evidence, and Policy RG, benefitting from interaction with a dynamic group of researchers working in tropical and UK landscapes to generate evidence for policy- and decision-making on pressing global challenges, including climate change mitigation through agroforestry, disease risk, human wildlife conflict, and biodiversity loss in changing landscapes.

References & further reading

Hurni et al. 2015 Current Opinion in Environmental Sustainability
König, et al 2020 Conservation Biology
Mansourian & Vallauri 2014 Environmental Management
Ndoli et al. 2017 Field Crops Research
Nyong et al. 2020 Agroforestry Systems
Rockström et al. 2017 Ambio

Further Information

Please contact Dr Roy Sanderson for further information. roy.sanderson@newcastle.ac.uk

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