Sustained mangrove reproduction despite major turnover in pollinator community composition at expanding range edge

Background and Aims
How well plants reproduce near their geographic range edge can determine whether distributions will shift in response to changing climate. Reproduction at the range edge can be limiting if pollinator scarcity leads to pollen limitation, or if abiotic stressors affect allocation to reproduction. For many animal-pollinated plants with expanding ranges, the mechanisms by which they have overcome these barriers are poorly understood.
Methods
In this study, we examined plant-pollinator interactions hypothesized to impact reproduction of the black mangrove, Avicennia germinans, which is expanding northward in coastal Florida, USA. We monitored insects visiting A. germinans populations varying in proximity to the geographic range edge, measured the pollen loads of the most common insect taxa and pollen receipt by A. germinans stigmas, and quantified flower and propagule production.
Key Results
We found that despite an 84% decline in median floral visits by insects at nor..., Data were collected over the course of three years at eleven sites containing A. germinans populations in eastern Florida. The southernmost sites (latitudes 27.1–27.9°N) contain mixed stands of all three Floridian mangrove species (with Rhizophora mangle L. [Rhizophoraceae] and Laguncularia racemosa [L.] C.F. Gaertn. [Combretaceae]), in varying stages of regeneration following impoundment for mosquito control in the first half of the 20th century. Farther north, in the southern reaches of the mangrove-marsh ecotone (latitudes 28.5–29.1°N), many sites are also recovering from impoundment or other human alteration, but here are characterized by mixed-mangrove stands edging waterways, with salt marsh vegetation (primarily Distichlis spicata [L.] Greene [Poaceae], Spartina alterniflora Loisel. [Poaceae], Batis maritima L. [Bataceae], and Salicornia sp. L. [Amaranthaceae]) landward. At the northern end of the study region (latitudes 29.6–29.9°N), sites contain some of Florida’s northernmost ..., Data files are CSVs and can be opened with any software compatible with this file type. The programming script is in R, originally written in R version 3.5.0.