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ABSTRACT AimAll bees depend on angiosperms for survival, while many angiosperms depend on bees for reproduction. However, bee and flowering plant species richness do not peak in the same geographical regions of the world, suggesting that the flora in regions where bees are not as diverse, such as the tropics, may be relatively less bee‐dependent. We test this assumption by analysing whether local relative bee diversity can predict the proportion of angiosperm species that attract bees (i.e., “bee flowers”). LocationThe Americas. Time PeriodPresent. Major Taxa StudiedBees and angiosperms. MethodsWe map the proportion of bees to angiosperm species using recently available datasets of geographic distribution for both taxa. We then combine data from surveys on pollination systems for 56 floristic communities to estimate the proportion of angiosperm species with bee flowers in different regions. Finally, we test whether the proportion of bee flowers in a community can be predicted by a combination of relative bee species richness and abiotic environmental variables. ResultsBroad distribution maps show that the relative richness of bees in relation to angiosperms decreases in tropical areas; however, there is no evidence that tropical floristic communities are less dependent on bees. Interestingly, the proportion of angiosperm species with bee flowers was almost always found to be around 50% across biomes, with some variation depending on the habitat type and method of data collection. Main ConclusionsOur results suggest that plant communities can be highly bee‐dependent even where bees are relatively less diverse. While lower species richness does not mean lower abundance, and fewer bee species of specific life histories can still provide adequate pollination supply for a large number of angiosperm species, this pattern may impact how bee flowers interact with bees in different areas, and consequently how bees and bee flower specialisations have evolved over time.
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The geographic range size and vulnerability to extinction of angiosperm epiphytes in the Atlantic Forest of Brazil
Abstract AimAngiosperm epiphytes have long been reported to have larger geographic ranges than terrestrial species, despite evidence of their outstanding diversity and endemism. This apparent contradiction calls for further investigation of epiphytes' poorly understood range size patterns. Here, we address the question of whether epiphytes have larger geographic ranges and different vulnerability to extinction than terrestrial species. LocationThe Atlantic Forest of Brazil, a global centre of tropical epiphyte diversity with relatively well‐known flora, where we can estimate the geographic ranges of a large number of species with reasonable confidence. Time periodOccurrence records from the 17th century to the year 2021. Major taxa studiedFlowering plants (angiosperms). MethodsWe downloaded, processed and cleaned all occurrence records for the angiosperm species native to the Atlantic Forest of Brazil available in the speciesLink network and the Global Biodiversity Information Facility. We estimated the extent of occurrence and area of occupancy of 12,679 native flowering plants, including 1251 epiphytic species. We compared the geographic ranges of epiphytes and other life forms at broad (e.g. Angiosperms, Monocots) and more restricted taxonomic scales (e.g. individual families), assuming species are independent entities and also when accounting for species phylogenetic dependence. ResultsWe found that epiphytes have among the smallest geographic ranges of flowering plants. We found no consistent evidence that epiphytism leads to differences in geographic ranges between close relatives. However, both epiphytes and non‐epiphytes in epiphyte‐rich lineages have small ranges and likely a high vulnerability to extinction. Main ConclusionsOur findings contrast with the long‐held hypothesis that epiphytes have larger geographic ranges than terrestrial species. Epiphytes and their close relatives share many diversification mechanisms and ecological adaptations (‘epiphyte‐like traits’), which probably explain why both sets of species have small range sizes and high vulnerability to extinction.
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- Award ID(s):
- 2021898
- PAR ID:
- 10508061
- Publisher / Repository:
- Wiley Online Library
- Date Published:
- Journal Name:
- Global Ecology and Biogeography
- Volume:
- 32
- Issue:
- 9
- ISSN:
- 1466-822X
- Page Range / eLocation ID:
- 1607 to 1617
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1111/geb.13718
