Salvia García Álvarez

Negative responses of highland pines to anthropogenic activities in inland Spain: a palaeoecological perspective

Palaeoecological evidence indicates that highland pines were dominant in extensive areas of the mountains of Central and Northern Iberia during the first half of the Holocene. However, following several millennia of anthropogenic pressure, their natural ranges are now severely reduced. Although pines have been frequently viewed as first-stage successional species responding positively to human disturbance, some recent palaeobotanical work has proposed fire disturbance and human deforestation as the main drivers of this vegetation turnover. To assess the strength of the evidence for this hypothesis and to identify other possible explanations for this scenario, we review the available information on past vegetation change in the mountains of northern inland Iberia. We have chosen data from several sites that offer good chronological control, including palynological records with microscopic charcoal data and sites with plant macro- and megafossil occurrence. We conclude that although the available long-term data are still fragmentary and that new methods are needed for a better understanding of the ecological history of Iberia, fire events and human activities (probably modulated by climate) have triggered the pine demise at different locations and different temporal scales. In addition, all palaeoxylological, palynological and charcoal results obtained so far are fully compatible with a rapid human-induced ecological change that could have caused a range contraction of highland pines in western Iberia.

Species selection for reforestations: what happens with historic local extinctions and habitat protection zones? A case study in the Cantabrian Range

Species selection for reforestations can be challenging in habitat protection zones, especially in human transformed landscapes, where nativeness of some species is not easily determined and yet is crucial for knowing whether a species can be used or not. We try to determine whether Pinus uncinata Ramond ex DC was present in the Cantabrian Range (Spain) and whether it could have disappeared recently due to anthropogenic causes. Plant morphology and needle anatomy were characterized in Pinus sylvestris L. and P. uncinata 2-year-old seedlings. An analysis of variance was used for selecting morphological markers capable of discriminating both species. These markers permit the comparison of seedlings coming from the highest zone of Puebla de Lillo relict pinewood (Cantabrian Range) with reference material from Castillo de Vinuesa (Iberian Range). This comparison was firstly made with two multivariate methods, a principal component analysis and a multivariate discriminant analysis. Subsequently, this was corroborated with the detection of a species-specific chloroplast DNA marker. The differences found between both species reflect the better adaptation of P. uncinata to typical highland environment. Several Puebla de Lillo seedlings had P. uncinata type morphology and haplotype, suggesting the presence of this species in the Cantabrian Range until recently. This discovery changes the current interpretation of the zone’s vegetation, enhancing the natural presence of highland open pinewoods. However, human activities (fire and livestock grazing) have driven them to extinction and have favoured the contemporary expansion of heathlands. Based on this P. uncinata case, we discuss how local extinctions can affect management and conservation policies negatively.