DOI: 10.25666/dataubfc-2025-03-28
title: Floral offer and seasonality shape plant-pollinator networks in tropical gardens

description: The dataset contains all the data and R code used in the analyses presented in a manuscript currently under review, along with a 'README.docx' document describing the contents and purpose of each file.

These materials support a study investigating how pollinator communities and plant-pollinator networks responded to spatial and temporal floral offer (i.e., floral abundance and composition) across private and communal gardens in a tropical urbanised landscape (Martinique, Lesser Antilles). Using a motif-based approach, we found that both floral abundance and composition shaped plant-pollinator interaction networks. Specifically, floral abundance enhanced pollinator species richness and interaction occurrences, but this effect was modulated by human-driven patterns in floral composition characteristics (i.e., human use, life form, and origin status). Seasonality induced a phenological mismatch between floral resources and wild insect pollinators: garden floral resources were at their lowest in the wet season when wild insect pollinator occurrences peaked, leading to greater pollinator specialism and plant generalism. The western honey bee Apis mellifera – a super-generalist alien pollinator – hugely dominated interactions, producing networks characterized by higher insect generalism, especially in the dry season when wild pollinator abundance and diversity were lowest. Insects contributed more to species turnover in communal gardens, whereas plants contributed more in private gardens, with overall plant contribution to species turnover far exceeding that of insects. Together, these patterns underscore the role of human floral management in shaping the structure of these mutualistic communities. As urbanization expands, fostering diverse and seasonally reliable floral resources through inclusive gardening practices may be key to conserving pollinators and sustaining their ecological roles.
description: Audience: General, Research, Policy maker
description: UpdatePeriodicity: no update
description: Project: Thèse de doctorat de Nathan Cyrille, Caribaea Initiative (Another national), Contrat doctoral Ministère de l'Enseignement Supérieur, de la Recherche et de l'Innovation (MESRI) (Ministry), DEAL Martinique (Another national), Université Bourgogne Europe (BQR)
description: Observational data: Floral offer and plant-pollinator interactions (insects and birds) were sampled monthly over 12 months (October 1, 2022 - September 12, 2023) in 10 tropical garden sites in Martinique (Lesser Antilles), including five communal gardens (C-sites; C1 to C5) and five neighbourhood clusters of five private gardens (P-sites; P1 to P5). Sampling was carried out by the same observer, using a transect method with one site surveyed per day and the sampling order of sites and transect sections randomly changed each month. Each survey (floral offer and interactions) was conducted along 150 m (total transect length) per site per month. For each private garden site, this spatial coverage was evenly distributed across the five private gardens, resulting in 30 m of coverage per individual garden. Each month, transect sections were distributed across distinct blooming flower patches to capture the floral diversity of the focal site at that time and to avoid spatial clustering, with positions and lengths adjusted from month to month to accommodate natural and/or human-induced changes in floral availability. Plants and pollinators were identified to the lowest taxonomic level possible and verified with expert taxonomists. For each site, monthly data were paired into six two-month periods (bi-periods) for analysis.

Floral offer survey
20 quadrats (1 × 1 m, up to 3.5 m in height) were randomly placed along transect sections (one per 7.5-m section). Within each quadrat, all blooming plant species were identified along with the number of their open floral units. A floral unit was defined as either a single flower or an inflorescence on which an insect of length l ≥ 0.5 cm could move between flowers without needing to fly. When a plant species had highly abundant and evenly distributed floral units within a quadrat, totals were estimated by counting a subset of the quadrat and scaling up.

Plant-pollinator interactions
1) Plant-insect and 2) plant-bird interactions were recorded separately, along the same transect sections used for sampling floral offer. An interaction was defined as floral visitor behaviour indicative of floral nectar or pollen collection. 1) Plant-insect interactions were monitored over 60 min per site (along the 150 m) per month at a constant speed (v = 2.5 m/min). Interactions were recorded within 1 m on either side of the transect line and up to 3.50 m in height. Insects were captured using a butterfly net and euthanised. 2) Plant-bird interactions were recorded from a distance. As an individual bird could be observed multiple times, each plant-bird species pair was counted only once per site per bi-period, resulting in unweighted (binary) interaction data. Each transect section was monitored for 10 min. To minimise disturbance to pollinators, bird-plant interactions were always recorded first, followed by insect-plant interactions, before conducting floral surveys.