Forest dynamics: Space-time patterns of biodiversity under changing management

Aims: We aimed to enhance the conservation of forest biodiversity investigating: (i) The suitability of sampling methods for assessing patterns and trends of plant diversity; (ii) The effects of forest management and abandonment on biodiversity. Main study area: Foreste Casentinesi National Park (Italy). Methods: (i) We generated a georeferenced data set by assembling the available forest vegetation data for the study area, to investigate their spatial and temporal patterns. Then, we analyzed the consistency between preferential and probabilistic samplings. Further, we performed a resurvey study based on the oldest vegetation data in the data set. (ii) We analyzed the effects of management vs. abandonment of mountain beech forests on vascular plants and epiphytes. Finally, we compared richness and functional diversity metrics in capturing the effects of management-related habitat factors on biodiversity, analyzing European beech forests in Denmark. Results: (i) The preferential survey provides a biased estimation of patterns and trends of plant diversity, while a probabilistic method is more statistically representative, but it may fail to record important biodiversity features. Therefore, both sources of information should be considered to maximize the effectiveness of plant diversity assessment and monitoring. Structural and compositional dynamics assessed in the resurvey study reflect a widespread process of abandonment of mountains in the second half of 20th century. (ii) Different species groups show contrasting responses to management and abandonment and at present the occurrence of conservation-relevant species results a relevant metric for planning and evaluating conservation actions, especially for less studied organism groups. Conclusions: The use of proper, and standardized, sampling methods and metrics for biodiversity assessment is baseline for an effective conservation planning. A multi-taxon approach is highly recommended to avoid misleading conclusion for conservation. Further studies to identify suitable indicators of overall biodiversity may support rapid assessment methods for practical conservation.