Enhancing biodiversity and the provision of water-based ecosystem services in agroforestry while considering smallholder preferences.
Aaron Willmott
Institute of Agricultural Sciences in the Tropics 490 Garbenstrasse 13, 70599 Stuttgart
Challenges/ Introduction
Agroecosystems in the tropics are increasingly tasked with being multifunctional; I.e., providing a range of ecosystem services while also being economically viable and preserving biodiversity. Such a task is fraught with difficulties and potential trade-offs. One potential way to approach this challenge is through certifications that aim to compensate farmers -via higher prices- for yield losses that may occur due to maintaining ecosystem services and biodiversity. However, establishing systems that meet the criteria of such certifications and monitoring them over time to ensure they achieve their promised outcomes are steps that require further research.
The studied systems include both established coconut and oil palm agroforestry systems, plantations run by small-holder cooperatives, as well as early-stage diversified coconut agroforestry systems in the Ivory Coast. Many of these systems are organic certified or are aiming to fulfil Switzerland’s relatively rigorous organic certification norm BioSuisse.
Aim
The aim of the thesis is the assessment and monitoring of certified agroforestry systems in the Ivory Coast while comparing different methods for improving the biodiversity and ecosystem service value of these systems with a particular focus on water-based ecosystem services and functions.
Objectives
- Objective 1: Compare establishment phase management practices in new coconut agroforests and monitor development over time, particularly focusing on biodiversity targets and soil water conditions.
- Objective 2: Given the certification requirements for habitat provision and connectivity, the development and effectiveness of habitat corridors in the coconut agroforests will be monitored.
- Objective 3: Compare established organic vs non-organic agroforests based on biodiversity and ecosystem service provision in smallholder coconut and oil palm cooperatives.
- Objective 4: Assess the potential of habitat interventions for improving pollination in organic oil palm and establish links between agroforestry properties and Elaeidobius kamerunicus abundance, oil palm’s primary pollinator.
- Objective 5: Present results from all of the above objectives to local smallholders and stakeholders for feedback on which interventions and management practices they deem feasible and worthwhile.
Methods
The foundations for comparison will be based on functional diversity, structural diversity and niche complementarity due to their relationship to ecosystem services and habitat provision. In addition to this, variations in management practices will be accounted for as well as landscape scale attributes. Primary observations will be soil water content and flux, humidity, bird and insect diversity and abundance assessed via birdsong recorders and insect traps, and biomass accumulation. Questionnaires which present preliminary and/or final results will be given to local smallholders and stakeholders so they can rate feasibility of implementing measures and practices that can improve ecosystem services and biodiversity and express they’re preferences. Field data will be analysed and used to adapt and improve existing modelling approaches for the assessment of functional diversity. Measurements of key parameters of the field water cycle will allow for an estimation of the impacts of the different management approaches on (seasonal) water scarcity within the system.
Expected results
By elucidating which factors improve the biodiversity and ecosystem service provision of established and establishing agroforests, management guidelines can be suggested that incorporate feedback from local smallholders. These can then inform the management of the establishing coconut agroforests and their landscape context. Generally, as the functional and structural diversity of an agroforest increases it is expected that the biodiversity and ecosystem service provision will also increase. However, trade-offs and points of diminishing returns are expected to be identified. Interventions and management changes that require less labour and fit easily into established work flows are expected to receive the most support from local smallholders and stakeholders. How well this aligns with the demonstrated effectiveness of the interventions will be useful for decision making going forward.