Biological properties of the endemic and threatened shrub in Iberia Vella pseudocytisus subsp. paui Gomez Campo (Cruciferae) and implications for its conservation

摘要

We present new data about chorology, seed bank, dispersal, seedling biology and population structure of the threatened endemic shrub Vella pseudocytisus subsp. paui Gomez Campo in Spain. In addition, we investigate human activities that are linked with the fine-scale distribution of the taxon to offer conservation recommendations. Currently, the plant occurs in two populations close to the city of Teruel (East central Spain), growing in an open shrubby community on patches of gypsum substrate surrounded by agricultural landscape. The plant has disappeared from two reported locations dated from early 20th Century likely due to human activities. The seed bank seems to be poor. A ballistic dispersal mechanism appears to move seeds between 0 and 4 m. We did not find a clear seasonal pattern of seedlings emergence although spring cohorts are the largest. Also, this period was where leaf seedling growth was more prominent. During the 3 years of our survey, the cumulative mortality was 94.2% of all seedlings plants. Plants are estimated to remain in the seedling stage for approximately 5 years. The demographic structure of both populations shows no apparent gaps in the distribution of size classes. Adult plants greater than 200 dm~3 represent the most important stage for seed production and persistence. We point out two key factors for conservation purposes, first the weakness of some of the plant biological properties for natural establishment and second its ability to colonise artificial environments. We propose a mitigation of clonal spread in those sites and the protection of juvenile stages in more natural locations.