Deforestation can impact the quality of pollen received by target plants (i.e., delivery of incompatible pollen, self-pollen, or pollen from closely related individuals). Such reductions in plant mating quality may be direct, when deforestation reduces plant population size and the availability of pollen donors, or indirect, when decreased mating quality results, for example, from shifts in the composition of the pollinator community. As most flowering plants depend on animal pollinators for reproduction, there is a need to understand the direct and indirect links between deforestation, pollinator community composition, and plant mating quality.

We quantified the direct, pollen-donor-mediated and indirect, pollinator-mediated effects of deforestation on mating quality in Heliconia tortuosa, a tropical herb pollinated by low- and high-mobility hummingbirds. We used a confirmatory path analysis to test the hypothesis that deforestation (amount of forest cover and forest patch size) influenced mating quality (haplotype diversity of pollen pools, outcrossing, and biparental inbreeding) directly and indirectly through functional shifts in the composition of pollinator communities (proportion of high-mobility hummingbirds).

We found that deforestation triggered functional shifts in the composition of pollinator communities, as the proportion of high-mobility hummingbirds increased significantly with the amount of forest cover and forest patch size. The composition of the pollinator community affected mating quality, as the haplotype diversity of pollen pools increased significantly with the proportion of high-mobility hummingbirds, while biparental inbreeding decreased significantly. Although we did not detect any significant direct, pollen-donor-mediated effects of deforestation on mating quality, reductions in the amount of forest cover and forest patch size resulted in functional shifts that filtered out high-mobility hummingbirds from the pollinator community, thereby reducing mating quality indirectly.

Synthesis. Deforestation primarily influenced plant mating quality through a cascading effect mediated by functional shifts in the composition of the pollinator community. Our results indicate that plant mating quality strongly depends on the composition of local pollinator communities. Functional shifts that filter out highly mobile and effective pollinators may reduce the transfer of genetically diverse pollen loads from unrelated plants. Such shifts may have pronounced effects on plant population dynamics and disrupt genetic connectivity.

This folder contains the raw input data and R scripts necessary to: (1) estimate the haplotype diversity (h) of pollen pools, outcrossing rates (tm), and biparental inbreeding (tm-ts); (2) estimate the proportion of high-mobility hummingbirds across focal forest patches; (3) run the confirmatory path analysis based on a piecewise SEM approach; and (4) recreate the main figures (graphs) of the paper. This folder contains the following files:

1. Data_Moms_Locations.csv

Spatial coordinates for all sampled maternal plants.

2. Data_Moms.csv

Summary data for all sampled maternal plants. For each sampled maternal plant, this file includes deforestation variables (amount of forest cover and forest patch size), data on the local pollinator community composition (proportion of high-mobility hummingbirds), and plant mating quality surrogates (haplotype diversity (h) of pollen pools, outcrossing rates (tm) and biparental inbreeding (tm-ts)).

3. Data_Patches.csv

Summary data for all sampled focal forest patches. For each focal forest patch, this file includes deforestation variables (amount of forest cover and forest patch size) and data on the local pollinator community composition (proportion of high-mobility hummingbirds).

4. Genotypes.csv

Genetic data (11 microsatellites) for all sampled maternal plants and selected seeds. The column “ID” is composed by the ID of each focal forest patch (first two numbers), followed be the ID of each maternal plant (letter character) and sampling year. The column “OffID” denotes whether a sample corresponds to a maternal plant (OffID = 0) or a seed (OffID ≠ 0).

5. Graphs.Rmd

R script necessary to recreate the main graphs (Figures 1 & 2) in the main text of the paper, plus Supplementary Figures 2 & 3.

6. Haplotype_Diversity_Pollen_Moms.csv

This file contains the estimated haplotype diversity (h) of pollen pools for each sampled maternal plant.

7. Hummingbird_Data.csv

Raw hummingbird capture data with mist nets. Summary data for each focal forest patch and number of unique hummingbird captures (identified to the species level).

8. piecewiseSEM.Rmd

R script necessary to run the confirmatory path analysis based on a piecewise SEM approach.

9. Pollen_Pool.Rmd

R script with function used to calculate the haplotype diversity (h) of pollen pools for each sampled maternal plant.

10. Pollinator_Community.Rmd

R script necessary to estimate the proportion of high-mobility hummingbirds per each focal forest patch (including small-sample size correction).

11. Proportion_High_Mobility_Pollinators.csv

Summary data for each focal forest patch. The total number of captures per species are shown for each forest patch, as well as the total number of high-mobility hummingbird captures and the total number of hummingbird captures. The proportion of high-mobility hummingbirds per forest patch (after small-sample size correction) is shown. Hummingbird species codes: CHRH (Amazilia decora), SNOB (Amazilia edward), RTAH (Amazilia tzacatl), VISA (Campylopterus hemileucurus), GCBR (Heliodoxa jacula), SBRH (Phaeochroa cuvierii), GREH (Phaethornis guy), LBIH (Phaethornis longirostris), and STHR (Phaethornis striigularis).