Ecological succession in oligotrophic pastures of central Spain

Long-term changes in game species over a long period of transformation in the Iberian Mediterranean landscape

Agricultural change has transformed large areas of traditional farming landscapes, leading to important changes in the species community assemblages in most European countries. We suspect that the drastic changes in land-use that have occurred in Andalusia (southern Spain) over recent decades, may have affected the distribution and abundance of game species in this region. This article compares the distribution of the main game species in Andalusia during the 1960s and 1990s, using data from maps available from the Mainland Spanish Fish, Game and National Parks Service and from recent datasets on hunting yield distributions, respectively. Big-game and small-game species were significantly segregated in southern Spain during the 1990s, as two clearly independent chorotypes (groups of species whose abundances are similarly distributed) were obtained from the classification analysis. In contrast, big-game and small-game species were not significantly segregated several decades ago, when there was only one chorotype consisting of small-game species and wild boar. The other three ungulates did not constitute a significant chorotype, as they showed positive correlations with some species in the group mentioned above. These changes seem to be a consequence of the transformations that have occurred in the Iberian Mediterranean landscape over the last few decades. The abandoning of traditional activities, and the consequent formation of dense scrubland and woodland, has led to an expansion of big-game species, and a decrease of small-game species in mountain areas. Moreover, agricultural intensification has apparently depleted small-game species populations in some agricultural areas. On the other hand, the increasingly intensive hunting management could be artificially boosting this segregation between small-game and big-game species. Our results suggest that the conservation and regeneration of traditional agricultural landscapes (like those predominating in the 1960s) should be a priority for the conservation of small-game species.

Effects of management on understory diversity in the forest ecosystems of northern Spain

Pine plantations are an alternative to marginal agriculture in many countries, and are often presented as an option that improves biodiversity. However, these plantations can have adverse environmental effects if improperly managed. To evaluate the effect of forest management practices on biodiversity, the diversity, species richness, dominance and frequency of understory woody plant species in different forests of the Basque Country (northern Spain) were compared. Plantations of exotic conifers (Pinus radiata [D.] Don) of different ages were compared with deciduous forests of Quercus robur L. and Fagus sylvatica L. The effects of different types and intensities of management were taken into account. The differences observed were mainly conditioned by the intensity of forestry management, although the response varied according to forest type and age. In unmanaged pine plantations, the diversity and species richness of the understory increased rapidly after planting (while dominance decreased), remained stable in the intermediate age range, and reached a maximum in plantations more than 25 years of age. Management practices resulted in decreased understory diversity and species richness, as well as greater dominance. This was more pronounced in younger than in older stands. Moderate management, however, favored a greater diversity of the understory in deciduous forests. The species composition of the plantations and deciduous forests were different, the latter having a wider range of characteristic species. Knowledge of how forestry practices influence biodiversity (in terms of diversity, richness, dominance, and species composition) may allow predictions to be made about the diversity achievable with different management systems.

Mediterranean pasture dynamics: the role of germination

Meteorological patterns have a decisive influence on the inter-annual dynamics of therophyte pastures under Mediterranean climatic conditions. The germination behaviour of annual pasture species was studied by subjecting two collections of seeds taken from plants and soil-seed banks to two phytotron-simulated weather patterns: early and late autumn rains. Species from these pastures were arranged along a gradient of sensitivity to temperature on the arrival of the first persistent rain. This sensitivity was manifested in both the total germination success of the species and the germination time profile. The different germination patterns of the species can provide competitive advantages depending on the autumn weather conditions.