Understanding the processes of naturalization of Eucalyptus globulus in Portugal through the use of remote sensing and genetic markers

Eucalyptus globulus is a fast-growing tree species native to Australia, introduced in Portugal by mid-19th century, being largely used as a source of pulpwood for the pulp and paper industry. It covers a large area in Portugal, being currently the most widely distributed tree species in the country. Previous research conducted under the WildGum (hereafter WildGum I) project reported the existence of naturalization processes, resulting in the establishment of wild eucalypt populations (WEP). The occurrence of WEP seems to be associated with rural abandonment and frequent wildfires, resulting in co-occurrence and competition between E. globulus and native vegetation. Although the extent and the key drivers of this naturalization process have been previously characterised, very little is known about how populations are originated and develop over time. WildGum II will address these knowledge gaps by studying a set of 10-15 eucalypt stands through the use of remote sensing, genetic markers and field work This combined approach will achieve four major goals: first, the establishment of parent-offspring relationships through parentage analysis using genetic markers and the historical information obtained from remote sensing, will allow tracing back the origins and rate of expansion of these populations; second, the historical data on vegetation cover will be complemented with aerial images obtained from a drone and field work, to assess the effect of WEP on native vegetation cover; third, data on the regional- and stand-scale drivers of wildling establishment obtained from WildGum I and from literature, will be explored together with the spatiotemporal information obtained by WildGum II, to model the establishment and expansion of WEP over time. Fourth, the genetic data from WEP will allow obtaining novel information on the population genetics of these eucalypt populations (population-level indices, genetic structure, gene flow and outcrossing rates) providing novel insights into the naturalisation process. The project is structured into six sequential tasks that will run over three years: 1 Site selection; 2 Sampling; 3 Genotyping; 4 Genetic analysis; 5 Statistical analysis and modelling; 6 Dissemination. WildGum II was developed and will be assisted by a multidisciplinary team of researchers, comprising specialists in forest genetics, invasion ecology, fire ecology and ecological modelling. The working force of this proposal includes researchers from three public academic institutions and a private research laboratory associated to the pulp industry, assisted by an international group of consultants.