DOI: 10.5061/dryad.kprr4xhcw
title: Data from: The contribution of hydric habitats to the richness of the Cape fynbos flora

description: Aim: The Cape Fold Belt Mountains, underlying the Cape fynbos flora,
 facilitate widespread moisture collection and groundwater availability
 across the region, with importance for maintaining hydric habitat niches.
 We assessed the contribution of hydric habitat associated species (HH
 species) to the richness of this flora, and how this varies
 phylogenetically and spatially. Location: The Cape Floristic Region (CFR),
 South Africa. Methods: We compiled data describing habitat preference, and
 distributions for 3114 species in 23 fynbos clades. We used published
 habitat descriptions to identify putative HH species and tested how hydric
 habitat association is structured phylogenetically using both
 Ornstein-Uhlenbeck models and measures of phylogenetic signal. We used
 species’ distribution data to identify regional hotspots of HH species and
 boosted regression trees to identify associated environmental drivers.
 Results: Preference for hydric habitats is associated with nearly a fifth
 of the species in our study, being most strongly represented in monocot
 clades. HH species are most strongly concentrated in the southwestern CFR,
 where they contribute to high overall richness. Boosted regression trees
 (BRTs) indicated that hotspots of HH species are generally associated with
 saturating, winter precipitation and/or elevated levels of groundwater
 discharge. Main conclusions: Our findings indicate that the unique
 climate, topography and hydrology of the CFR facilitate the formation and
 maintenance of important hydric habitats, which play host to a large
 fraction of the flora despite much of the region being semi- or seasonally
 arid. These findings highlight the threat of climate change and underscore
 the need for extreme caution regarding activities like groundwater
 abstraction, which could disrupt the hydrological processes essential to
 sustaining these habitats and their unique flora.
description: # Data supporting the study: "The contribution of groundwater to the
 diversity of the Cape fynbos flora."
 [https://doi.org/10.5061/dryad.kprr4xhcw](https://doi.org/10.5061/dryad.kprr4xhcw) **Provided files:** 1\) [Species_location_habitat_data.csv] Our primary dataset consists of species location data paired with habitat preferences for 3114 species in 23 Cape fynbos clades. These data were used to quantify total species richness and hydric habitat associated species richness. The dataset contains columns, 'Genus' [e.g., 'Acmadenia'], 'Species' [e.g.,'patentifolia'], 'Decimal Latitude' [e.g., '-32.375'] , 'Decimal Longitude' [e.g., '19.375'], 'Clade' [e.g. 'Diosmeae'], 'Microhabitat' [e.g., 'marsh'...] and 'Hydric habitat associated' [e.g., 'Yes'] * Habitat preference data was primarily sourced from (Manning and Goldblatt 2012) and more recent taxonomic updates. See manuscript for full list of references. * Species location data was sourced from (South African National Biodiversity Institute. (2016). Botanical Database of Southern Africa (BODATSA). [https://posa.sanbi.org/)](https://posa.sanbi.org/) 2\) [QDS_grid.shp] Species richness and hydric habitat associated species richness was summarized across a quarter degree square grid for South Africa prior to analysis. 3\) [Elevation_250m.tiff] Derived from a digital elevation model sourced from (https ://earth [explorer.usgs.gov](http://explorer.usgs.gov/); accessed May 2019). Spatial layers containing climatic, topographic and hydrological information were summarized at the QDS resolution and were used in boosted regression tree models to explain the spatial distribution of hydric habitat associated species. 4\) [TRI_250m.tiff] Terrain Ruggedness Index derived from the digital elevation model. Spatial layers containing climatic, topographic and hydrological information were summarized at the QDS resolution and were used in boosted regression tree models to explain the spatial distribution of hydric habitat associated species. **Other files required:** 5\) South African Vegetation Map. Used to delineate the study area. Sourced from (South African National Biodiversity Institute (2006-2018). The Vegetation Map of South Africa, Lesotho and Swaziland, Mucina, L., Rutherford, M.C. and Powrie, L.W. (Editors), Online, [http://bgis.sanbi.org/Projects/Detail/186](http://bgis.sanbi.org/Projects/Detail/186), Version 2018.) 6\) Angiosperm phylogeny. Sourced from (Zanne, A. E., Tank, D. C., Cornwell, W. K., Eastman, J. M., Smith, S. A., FitzJohn, R. G., McGlinn, D. J., O’Meara, B. C., Moles, A. T., Reich, P. B., Royer, D. L., Soltis, D. E., Stevens, P. F., Westoby, M., Wright, I. J., Aarssen, L., Bertin, R. I., Calaminus, A., Govaerts, R., … Beaulieu, J. M. (2014). Three keys to the radiation of angiosperms into freezing environments. *Nature*, *506*(7486), 89–92.) The phylogeny was pruned to include a single representative from each focal clade. We used this pruned phylogeny to analyze the phylogenetic structure of hydric habitat association across clades. 7\) Other spatial environmental layers used in our boosted regression tree models. * Bio1 (Mean Annual Temp - degrees Celsius), Bio10 (Mean Temp Warmest Quarter - degrees Celsius), Bio11 (Mean Temp Coldest Quarter - degrees Celsius), Bio12 (Mean Annual Precipitation - mm), Bio18 (Precipitation Warmest Quarter - mm), Bio19 (Precipitation Coldest Quarter - mm) sourced from (Fick, S.E. and R.J. Hijmans. (2017). Worldclim 2: New 1-km spatial resolution climate surfaces for global land areas. International Journal of Climatology. [https://www.worldclim.org/).](https://www.worldclim.org/) * Groundwater contribution to baseflow (m^3 km^-2) sourced from (Groundwater Resource Assessment II, Task 2C Groundwater Planning Potential Report (Project number 2003-150, 1 Final version 2006-02-24.) Spatial layers containing climatic, topographic and hydrological information were summarized at the QDS resolution and were used in boosted regression tree models to explain the spatial distribution of hydric habitat associated species.