10.5061/DRYAD.QZ612JMFH
Méndez Castro, Francisco Emmanuel
0000-0002-8926-2490
Academy of Sciences of the Czech Republic
Conti, Luisa
Czech Academy of Sciences
Chytrý, Milan
Masaryk University
Jimenez-Alfaro, Borja
University of Oviedo
Hajek, Michal
Masaryk University
Horsák, Michal
Masaryk University
Zeleny, David
National Taiwan University
Malavasi, Marco
Czech University of Life Sciences Prague
Ottaviani, Gianluigi
Academy of Sciences of the Czech Republic
What defines insularity for plants in edaphic islands?
Dryad
dataset
2021
edaphic island
Island size
Isolation
specialists species richness
target effect
FOS: Biological sciences
2021-05-27T00:00:00Z
2021-05-27T00:00:00Z
en
https://doi.org/10.5281/zenodo.4752959
47194 bytes
4
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
The Theory of Island Biogeography postulates that size and isolation are
key drivers of biodiversity on islands. This theory has been applied not
only to true (e.g. oceanic) islands but also to terrestrial island-like
systems (e.g. edaphic islands). Recently, a debate has opened as to
whether terrestrial island-like systems function like true islands.
However, identifying the effect of insularity in terrestrial systems is
conceptually and methodologically challenging because recognizing species
source(s) and measuring isolation is not as straightforward as for true
islands. We contribute to the debate by proposing an approach to
contextualize the definition of insularity and to identify the role of
isolation in terrestrial island-like systems. To test this approach, we
explored the relationship between insularity predictors and specialist
species richness of edaphic islands in three systems in Europe (spring
fens, mountaintops, and outcrops). We detected that insularity affected
specialist richness of edaphic islands through island size and target
effect (i.e. an emergent property of islands depending on their isolation
and size). As predicted by the Theory of Island Biogeography, species
richness decreased with increasing isolation. Given the comprehensiveness
and ease of implementation of our approach, we encourage its extension to
other island-like systems.
Floristic data The dataset contains floristic information about three
different edaphic island systems in Europe: 1) calcareous spring fens in
the Western Carpathians (Slovakia and the easternmost Czech Republic;
hereafter fens), 2) acidic alpine grasslands in Cantabrian mountaintops
(north-western Spain; hereafter mountaintops), and 3) shallow-soil
acidophilous grasslands in Moravian granite outcrops (southern Czech
Republic; hereafter outcrops). We worked with vascular plant specialist
species of each focal habitat type (edaphic island). These species are
exclusively or tightly associated with the edaphic islands, unable to
establish viable populations elsewhere in the landscape matrix. In fens,
data was collected using a single 4 m x 4 m plot located at the central
part of each island. This species inventory was then completed by a census
of the whole edaphic island. In mountaintops, a total of 284 vegetation
plots (size between 10 and 40 m2) were used to sample alpine grasslands in
isolated patches with acidic bedrock, with a number of plots per island
associated with the island area. In outcrops, sampling was performed using
four 0.5 m x 0.5 m plots per island and complemented by a census of the
whole edaphic island, similarly to what was done for fens. We gathered
data on 49 edaphic islands for fens, 25 for mountaintops, and 20 for
outcrops. Expert-based selection of habitat specialists was carried out in
each study system. Biogeographic data We identified and delimited the
edaphic islands by combining different techniques. In fens, all known
patches found in the Western Carpathians were manually georeferenced using
a GPS device. For mountaintops, we built a map by selecting edaphic
islands above the regional treeline (1800 m a.s.l.) occurring on acidic
bedrock only. We differentiated alpine grasslands from rocky and shrub
areas based on the Normalized Difference Vegetation Index (NDVI) taken
from Sentinel 2 (USGS 2019). For outcrops, the location of edaphic islands
was obtained through a field survey using a GPS device (Garmin eTrex 30x)
and a vegetation map provided by the Nature Conservation Agency of the
Czech Republic. All the GPS points, satellite data, maps, and polygon
layers were processed and analyzed using QGIS desktop. All
distance-related metrics were calculated using direct aerial Euclidean
distance without considering differences in the terrain elevation.