Data from: Lichen traits responding to aridity

1. Climate change is expected to cause several impacts at the global scale
and drylands will be among the most affected areas. Thus, investigating
how these changes will affect the composition, structure and functioning
of dryland ecosystems has become a priority. From an ecological indicator
point of view, several works have shown that functional diversity is
better than species richness to understand ecosystem functioning or
response to environmental factors. However most of these works focus on
plants while those of other organisms remain largely unknown. Lichens are
amongst the ecosystem components more sensitive to climatic changes due to
several physiological and ecological characteristics. Their poikilohydric
nature (therefore highly dependent on the atmosphere for water supply) and
their ubiquity on terrestrial ecosystems underlie their potential as
indicators of climate. Nonetheless, works specifically aiming to identify
lichen functional traits that respond to aridity remain poorly explored,
particularly in drylands. 2. We proposed to identify lichen functional
traits and respective functional groups responding to aridity in a
Mediterranean drylands ecosystem. 3. Lichen diversity was sampled in open
holm-oak woodlands along an aridity gradient in SW Europe (Iberian
Peninsula). Lichen functional traits that could be easily identified and
related to water uptake were selected to be tested: type of photobiont,
growth form and reproduction strategy. 4. Lichen species composition was
related to the aridity gradient. The three traits chosen were related with
the community's response to aridity, but with contrasting responses
in different functional groups. More specifically crustose and fruticose
lichens, isidiate species and the ones with Trentepohlia as photobiont
were related to the less arid part of the gradient. Foliose species and
cyanolichens, on the contrary, were associated with the most arid areas.
5. Synthesis We were able to identify lichen traits responding to aridity.
Type of photobiont was particularly responsive, with Trentepohlia and
cyanobacteria functional groups, responding clearly in contrasting ways to
aridity in this drylands ecosystem. This work emphasizes functional
diversity role on understanding and assessing the response to
environmental factors, namely to climate. It also highlights the potential
use of lichen functional groups as ecological indicators of climate
change.