Unsustainable soil management has led to well-documented declines in abundance and diversity of flora and increased pesticide usage, leading to a global overwhelming loss of habitat use by pollinators in intensive grasslands (pastures). Pastoral systems are increasingly challenged in their efforts to secure productivity and livestock, while supporting other ecosystem services, such as pollination. But there is no reason for these to be mutually exclusive. So far, very few studies used soil engineering strategies to improve pollinator habitat in grasslands, despite results from pot experiments looking promising. The literature suggests that it is possible to enhance pollinator habitat use through soil amendment with organic/inorganic substrates, leading to improved floral production, visual characteristics and pollen/nectar abundance. Also, insect abundance and diversity were positively correlate with improved soil structure, moisture and nutrient contents upon soil fertilization, with increased flower visitation rates and pollen protein contents. We anticipate biochar to have comparable outcomes for pollinators.
There is compelling evidence, including from previous/on-going work by POLLINATE’s team, that tailor-made biochars can simultaneously, improve soil structure, water availability and nutrient dynamics in degraded soils, thus promoting aboveground biomass growth and yield. POLLINATE’s pioneer concept and approach branches from these observations. It was designed to evaluate if, and how, engineering soil conditions through biochar may improve ecosystem characteristics that are directly linked to pollinator habitat use in pastures (as proof-of-concept). Based on the PI and co-Pi >10 years of biochar research experience, we hypothesise that biochar can simultaneously improve: a) floral visual (e.g. nº, size, colour) and olfactory (volatile profiles) display that is linked to attraction cues; b) pollen/nectar abundance and quality (e.g. nutritional value, reduced pesticide content); and c) burrowing/nesting conditions for ground-nesting communities (e.g. reduced soil compaction and resistance to penetration).
At the time of writing, a Scopus search found no scientific publications with biochar AND pollinators in keywords/title/abstract. But while it is a novel, timely and exciting concept, it is not topic for an exploratory project per se, since there is already evidence that biochar has the potential to achieve this goal. In fact, a pot-based fertilization study was first to report increased flower visitation by pollinators in biochar-amended soil. But the extent, and through which abiotic mechanisms, biochar can boost pollinator habitat use in pastures remains largely a knowledge gap. To this aim, POLLINATE successfully integrates biochar-based ecosystem management strategies, botany and ecology of sown pastures, insect ecology/monitoring and sampling approaches, as well as stakeholder engagement/participatory techniques, as core expertise. It combines interdisciplinary hands-on knowledge from 2 leading Portuguese research institutions (UAVR and IST-DT), collaborates with 2 on-going projects from the host research group (UAVR/CESAM) and benefits from involvement of 2 expert Consultants, which combined support maximises output in specific Tasks, as well as dissemination, knowledge transfer and possibly, implementation of POLLINATE’s results. POLLINATE’s hired HR are vital for its deliverables on time, combining more experienced researchers (postdoc/PhD student), which integration at the UAVR will be facilitated by POLLINATE, with younger researcher students (MSc), which POLLINATE will train till successfully obtaining their degree.
Structurally, POLLINATE relies on pot and field assays, running simultaneously throughout the project, with the pot comp onent providing the mechanistic evaluation of the observed effects. In turn, the field component takes place in Terraprima’s sown biodiverse pasture at Quinta da França (QF), where the PI and co-Pi already have an ongoing collaboration through project SOILCOMBAT (PTDC/EAM-AMB/0474/2020). It also combines, for the first time, state-of-art technology to assess biochar impact on pollinators visual (e.g. infra-red spectral reflectance to assess changes in leaf and flower hues) and olfactory (e.g. electronic-nose fingerprinting of floral scent) perception, motion-triggered camera surveillance to monitor pollinator-flower visitation and a multispectral drone to aid in location of potential pollinator ground-nests on-site. Generated audio-visual data is expected to maximise dissemination outputs (e.g. videos of pollinator-flower interactions), while minimising invasive insect sampling methods. POLLINATE outcomes are expected to benefit research, stakeholders and society to different extents, thus directly and indirectly, contributing to UN sustainability targets nº15,13,17.
