DOI: 10.5061/dryad.3bk3j9krt
title: Data from: Niche evolution during allopatric and sympatric diversification of Aeonium (Crassulaceae) on the Canary Islands

description: Although species radiations on island archipelagos are broadly studied,
 the geographic and ecological modes of speciation that underlie
 diversification are often not fully understood. Both allopatry and
 sympatry play a role during radiations, particularly on islands with
 profound habitat diversity. Here, we use the most diverse Canary Island
 plant radiation, Aeonium (Crassulaceae), to phylogenetically test two
 hypotheses: (1) allopatric speciation, which predicts that closely related
 taxa are ecologically similar but do not co-occur, and (2) sympatric
 speciation, whereby closely related taxa co-occur geographically but are
 ecologically distinct. We fitted niche and spatial distribution models
 based on extensive field surveys to quantify geographic and ecological
 divergence among taxa integrated in a phylogenetic context. Contrary to
 our expectation, phylogenetically closely related species tend to occupy
 similar ecological niches, revealing that ecological niche divergence
 among species accumulates slowly, even in sympatry. This suggests that
 evolutionary young taxa may be partially reproductively isolated due to
 subtle phenotypic differences, such as reproductive morphology and
 phenology, rather than by ecological niche and may putatively exacerbate
 divergence among populations. Thus, allopatry and sympatry are
 complementary speciation mechanisms on oceanic islands, jointly spurring
 this enigmatic radiation.
description: We surveyed the archipelago, covering all 38 <em>Aeonium
 </em>species and subspecies following Bañares-Baudet (2015). Surveys
 were performed between February and September in 2018–2020 and aimed at
 capturing the ecological breadth of the islands through high-resolution
 presence/absence observation points. To guarantee a dense and stratified
 sampling, we divided each sampled island into climatic quarters based on
 the average of the mean annual temperature (bio01) and annual
 precipitation (bio12): 1) dry and hot; 2) dry and cold; 3) wet and hot; 4)
 wet and cold. The quarters of each island were sampled through extensive
 driving and hiking. A total of 10’180 data points were collected using a
 Global Positioning System receiver (GPS 72H, Garmin, Taiwan) with a
 positional accuracy of ~ 5 m, including 9’719 presences (including data
 points with multi-taxa occurrences) and 2’450 absences. Points were
 registered at c. 50 – 200 m intervals, noting all
 occurring <em>Aeonium</em> species. For each island, we
 observed all <em>Aeonium</em> taxa known to occur.
 Fuerteventura was not visited because its only species was scored from
 Lanzarote.  
description: # Spatial dataset with presences and absences of the Aeonium genus
 (Crassulaceae) from the Canary Islands
 [https://doi.org/10.5061/dryad.3bk3j9krt](https://doi.org/10.5061/dryad.3bk3j9krt) The Dataset includes field-collected presences and absences for 38 taxa (species and subspecies) of *Aeonium* (Crassulaceae). The surveys on the Canary Islands include the islands of El Hierro, Gran Canaria, Lanzarote, La Gomera, La Palma, and Tenerife. ## Description of the data and file structure The dataset has 43 columns, including "ID" (a unique value that identifies the spatial point), "sur" (the origin of the points, numbers 1-4 indicate different field surveys), "lon" (longitude), "lat" (latitude), "p_a" (indicates presence or absence: "a" is absence, "p" is field collected presence which can include multiple co-occurring taxa, "fp" indicates presences collected from public datasets), "aiz" to "vol" indicate the 38 taxa, on each point "0" indicates absence and "1" indicates a presence. Some *Aeonium* species and subspecies are under threat, according to the IUCN. Furthermore, most have not been evaluated in recent years, and our field efforts demonstrate that populations of some species have disappeared or are under threat. For this reason, we followed the DRYAD Guidance for species data ([https://datadryad.org/docs/EndangeredSpeciesData.pdf](https://datadryad.org/docs/EndangeredSpeciesData.pdf)) to protect the integrity of the populations surveyed. We considered all species with a "near threatened" risk level, except those already assessed by the IUCN and classified as Vulnerable, Endangered, or critically endangered. A table with the taxonomic identifications of the taxa was included. The first column corresponds to the taxa code from the dataset; the second column corresponds to the full taxonomic name; the third column indicates the distribution of each taxon with the following letter code: Gc: Gran Canaria, Fv: Fuerteventura, Gm: La Gomera, Hr: El Hierro, Lz: Lanzarote, Pa: La Palma, Tf: Tenerife; the fourth column indicates the total number of observations per taxon. ## Sharing/Access information All data was collected in field surveys (see details in the Methods).