PRESENTATION

Main scientific area     Área científica principal      Hauptwissenschaftlicher Bereich

Secondary scientific area      Área científica secundária      Nebenwissenschaftlicher Bereich

Consequences of past and present climatic changes on biodiversity patterns of peat-rich environments: from genes to communities

Consequências das alterações climáticas passadas e presentes nos padrões de biodiversidade de ambientes turfosos: dos genes às comunidades

Folgen der vergangenen und gegenwärtigen Klimaveränderungen auf die Biodiversitätsmuster von torfreichen Umwelten: Vom Gen zur Gemeinschaft

Summary      Sumário      Zusammenfassung

Glacial refugia are often linked to the persistence of different genetic lineages during Terciary or Quaternary climate oscillations and thus of high genetic diversity and differentiation. Recent research proved that regional Mediterranean hotspots include an extremely high number of glacial refugia (Médail & Diadema 2009).
Identification of refugia may be critical in spatial planning policies and conservation strategies, as they constitute significant reservoirs of threatened genetic diversity. Of the 52 plant refugia identified by Médail & Diadema (2009) for the Mediterranean bioclimatic region, 25 are included in three peninsulas: the Balkan, Iberian and Italian peninsulas. Among these, the Iberian Peninsula has the highest number of refugia (12). It is therefore an ideal place for studies on the issue of glacial refugia. In Portugal,  three areas are considered putative refugia (Beira Litoral, Estremadura, Algarve), but other areas in mainland Portugal may have also as plant refugia, namely the Sado and coastal Alentejo regions. This project might prove the validity of these areas as refugia, particularly for turfophilous plants. We have identified in Portugal several peatland areas with isolated populations of species with temperate optimum (Neto et al., 2005 and 2007), namely in Estremadura, along the mouth of the Sado River and along coastal Alentejo, which may constitute such refugia.

To understand the paleobiogeographic effects of Quaternary climate changes, upon plant species occurring in a specific community, peat-rich environments, we will use a combination of different approaches: (1) morphological and phytosociological information, (2) palaeobotanical and palynological information and (3) phylogeographic analyses based upon genetic data, of several populations of four tufophilous species’ populations. This multi-proxy approach will provide a comprehensive picture of the history of these environments, the relationship among southern peninsular refugia and Central European populations, and of the genetic diversity structure, population structure and gene flow among the populations of the four target species.
Several important questions are to be answered:
- the characterization and location of glacial refugia of wetland species;
- whether the Pyrenees played the role of a biogeographical barrier in the separation of genetically differentiated populations;
- what migration routes were used by our studied peatland species, especially in SW Europe;
- infer the consequences of Quartenary climate change upon European peatland communities;
- and what are the future evolutive scenarios concerning recent and prospective climate changes.

The main purpose of this research project is to study the palaeoclimatic and palaeobiogeographic meanings of the rare isolated peat-bog communities in the southwest of the Iberian Peninsula, in particular, its role in contributing to the post-glacial expansion and restoration of present-day communities in Central and Northern Europe. Such role is to be put to the test with the role and contribution of the other two classic alternative refuges, Italy and the Balkans. Not past this point sampling in multiple populations of Iberian, Apennine, Balkans and Central Europe has been mandatory. The focus is centered upon populations of four acidic to peat-habitat taxa, for which is is to be checked if:

a) the Iberian Peninsula represents a glacial retreat refugium, from which there were movements of expansion and recolonization northward during interglacials, and which is its role in contrast to the roles of the Italian and Balkan refugia, which have proved important in many other species (Hewitt et al., 2004; Schmitt, 2007);
b) there is found any contrast among the Iberian populations, and in particular if the Portuguese southwestern populations represent recent colonization (essentially post glacial) from refuges further north - the Peninsula understood here as the very center of  differentiation for separate populations whose chorology can be explained on the basis of studies on Quaternal climate shifts and  biogeographical models of plant migration during this geological period;
c) the peninsular populations were, consistently, geographically and genetically isolated from other European populations during the Quaternary, largely due to the barrier posed by the Pyrenees;
d) the climate of southwest Iberia is going to affect, according to different scenarios of the IPCC, peat-rich soil communities of southwestern Europe.