Doctoral defence: Diego Pires Ferraz Da Trindade “Dark diversity dynamics linked to global change: taxonomic and functional perspective”

On 12 May at 10:15 Diego Pires Ferraz Da Trindade will defend his doctoral thesis “Dark diversity dynamics linked to global change: taxonomic and functional perspective” for obtaining the degree of Doctor of Philosophy (in Botany and Mycology).

Supervisors:
Prof. Meelis Pärtel, University of Tartu
Assoc. Prof. Carlos Pérez Carmona, University of Tartu

Opponent:
Dr. Petr Keil, Czech University of Life Sciences Prague (Czech Republic)

Summary
Dark diversity - the set of suitable but locally absent species - is an important concept to understand how ecological communities are assembled from regional to local scales. Dark diversity is the counterpart of observed diversity, which together form site-specific species pool. However, given that global change drivers affect community assembly processes across space and time, prior to this thesis no studies had explored how dark diversity could be useful to examine biodiversity dynamics in Anthropocene. Dark diversity may improve how we quantify and assess biodiversity change, and, consequently, enhance nature conservation. In this thesis, I advanced the role of dark diversity as a tool to examine biodiversity change by developing a conceptual framework in which species gains and losses are decomposed within and between species pools, revealing different biodiversity flows with possible time lags. Over millennial temporal scales, the dark diversity concept successfully depicted plant taxa facing expansion lags in their geographic range; species becoming suitable for changed environments but remaining absent. Functional traits revealed that taxa persisting in dark diversity over the Holocene and, thereby, in expansion lags, were those displaying high functional redundancy, and fast-life history trait strategies (linked to low dispersal ability and high stress intolerance). Moreover, I propose that dark diversity and functional traits can be used to enhance the nature conservation of warming sensitive organisms (e.g. lichens) by revealing which species and traits are mostly threatened to go regionally extinct or could be used in restoration. To conclude, with this thesis, I suggest that, since dark diversity is applicable to any taxonomic group, time period and global change driver, revealing how much, how fast and in what direction the whole species pool is changing, it is a promising approach to examine biodiversity in a changing world.