Διαδικτυακή Πύλη Συνεργασίας Για Τα Δάση

The role of modern climatic microrefugia is a neglected aspect in the study of biotic responses to anthropogenic climate change. Current projections of species redistribution at continental extent are based on climatic grids of coarse (≥ 1 km) resolutions that fail to capture spatiotemporal dynamics associated with climatic microrefugia. Here, we review recent methods to model the climatic component of potential microrefugia and highlight research gaps in accounting for the buffering capacity due to biophysical processes operating at very fine (< 1 m) resolutions (e.g. canopy cover) and the associated microclimatic stability over time (i.e. decoupling). To overcome this challenge, we propose a spatially hierarchical downscaling framework combining a free-air temperature grid at 1 km resolution, a digital elevation model at 25 m resolution and small-footprint light detection-and-ranging (LiDAR) data at 50 cm resolution with knowledge from the literature to mechanistically model sub-canopy temperatures and account for microclimatic decoupling. We applied this framework on a virtual sub-canopy species and simulated the impact of a warming scenario on its potential distribution. Modelling sub-canopy temperatures at 50 cm resolution and accounting for microclimatic stability over time enlarges the range of temperature conditions towards the cold end of the gradient, mitigates regional temperature changes and decreases extirpation risks. Incorporating these spatiotemporal dynamics into species redistribution models, being correlative, mechanistic or hybrid, will increase the probability of local persistence, which has important consequences in the understanding of the capacity of species to adapt. We finally provide a synthesis on additional ways that the field could move towards effectively considering potential climatic microrefugia for species redistribution.

Στην εργασία αυτή παρουσιάζεται η έρευνα που διεξάγεται στο Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης σχετικά με την ανάπαλση (resilience) των Μεσογειακών δασικών οικοσυστημάτων. Επίσης παρουσιάζεται το Έργου του 7ου Προγράμματος Πλαισίου για την Έρευνα και την Τεχνολογική Ανάπτυξη της Ευρωπαϊκής Επιτροπής «Ενοποιημένη Έρευνα για την Αντοχή και Διαχείριση Δασών στη Μεσόγειο» (Integrated Research on Forest Resilience and Management in the Mediterranean) και η πρόοδος υλοποίησης αυτού στο Α.Π.Θ.

In the present study, we aimed to contribute on the knowledge about the importance of adaptive management in the Mediterranean afforestations. To do so, we selected Aleppo pine (Pinus halepensis Mill.) as our study system. This species is the most widely distributed pine species throughout the Mediterranean Basin and one of the best adapted tree species to drought (Pausas 2004). Aleppo pine is subjected to frequent summer droughts (De Luis et al. 2007) and it is one of the Mediterranean forest species most used in reforestation programmes, especially in semi-arid areas of the Iberian Peninsula (Montero 1997). The adaptation of Aleppo pine to these Mediterranean climate conditions is determined by its resistance to water-stress in long periods of droughts as well as its recovery capacity after drought occurrence. For this study, we used dendrochronological methods over afforested stands of managed Pinus halepensis in the Mediterranean area. The main objectives were i) to assess the growth reactions to thinning on tree growth and ii) to evaluate the effects of thinning on climate-growth responses and drought sensitivity.

Observational records from 1950 onwards and climate projections for the 21st century provide evidence that droughts are a recurrent climate feature in large parts of Europe, especially in the Mediterranean, but also in western, south-eastern and central Europe. Trends over the past 60 years show an increasing frequency, duration and intensity of droughts in these regions, while a negative trend has been observed in north-eastern Europe. With a changing climate, this tendency is likely to be reinforced during the 21st century, affecting a wide range of socioeconomic sectors. The findings presented in this report result from the analysis of climatological data and climate projections made as part of the GAP-PESETA project. This project aimed to gain insights into the patterns of climate change impacts in Europe until the end of the 21st century. The report provides a detailed description of the characteristics of drought events (i.e. their frequency, duration, intensity, severity) across Europe, and their evolution over the period 1950 to 2012, as well as projections until the end of the 21st century. A pan-European database of meteorological drought events for the period 1950-2012 and of their related sectorial impacts has been built and a framework developed that links drought severity to expected damages under present and future climate.