We still know little about the biodiversity of the Mediterranean islands
A survey of the main databases on the distribution of plant species has revealed that data are available for only 790 of the 2,217 islands considered: a gap that needs to be filled if we are to ensure the conservation of the region’s ecosystems
"The lack of botanical data for an area so rich in biodiversity and so heavily transformed by human action is a prime example of just how little we still know about the biodiversity of this region”
Most Mediterranean islands are not included in plant biodiversity distribution databases: this is a significant shortcoming that could affect our ecosystem conservation strategies. Raising the alarm – with a survey published in the journal Ecography – is a research group led by scholars from the University of Bologna.
The analysis considered 2,217 Mediterranean islands and compared three major biodiversity databases, to assess how many and which plant species were recorded. The results showed that data on plant species are recorded on only 790 islands (35.6% of the total), while the others are entirely absent from the databases.
"We found that there is a lot of data for large islands such as Sicily, Sardinia and Cyprus, but the amount of data available drops dramatically for smaller islands, which are far more numerous and often harder to reach", explains Alessandro Chiarucci, Professor at the Department of Biological, Geological and Environmental Sciences - BiGeA, University of Bologna, who coordinated the study. "Moreover, areas such as the North African islands, the areas surrounding Sardinia, or some Greek and Turkish islands show a lack of data despite some studies having been carried out in these places over the last century".
The creation of biodiversity databases has made it possible to achieve major advances in the field of ecology and in biogeography. Having access to large quantities of data in an accessible and standardised way makes it possible to reconstruct and compare the distribution of natural biodiversity across many geographical areas.
However, despite their great potential, biodiversity documentation databases have historically had limitations, starting with the different nature of the data collected and the collection locations themselves, which are often only those that are easiest to access. As a result, significant gaps may emerge such as the one now highlighted for the Mediterranean islands.
"The lack of botanical data for an area so rich in biodiversity and so heavily transformed by human action is a prime example of just how little we still know about the biodiversity of this region” says Alessandro Chiarucci. “Therefore, it is essential that researchers join forces to fill these gaps and safeguard the extraordinary treasure trove of biodiversity of the Mediterranean islands: an endeavour that requires adequate research funding".
The scholars first and foremost highlight the importance of the work of digitising historical data, such as regional floras and herbarium records. This should then be complemented by regular updating, to identify and report ongoing changes, particularly for invasive or alien species that have been introduced recently.
"Field surveys should prioritise those islands that are currently under-sampled and the most neglected taxa", explains Francesco Santi, a PhD student at the University of Bologna, first author of the study. "Furthermore, citizen science initiatives, backed by expert validation, can be of great assistance in data collection, particularly for under-recorded species groups or alien species".
The study was published in Ecography, one of the leading scientific journals dedicated to the study of biodiversity in nature, with the title “Plant diversity of Mediterranean islands differ among biodiversity databases”. The survey was led by the research group BIOME (Biodiversity & MacroEcology) at the University of Bologna: Francesco Santi, Riccardo Testolin, Michele Di Musciano, Federico Bombardi, Vanessa Bruzzaniti, Michele Lussu, Sofia Prandelli, Diletta Santovito, Piero Zannini and Alessandro Chiarucci.