Applicazione di indici biologici nella valutazione dell'impatto dei cambiamenti climatici sugli ecosistemi forestali
Author(s)
Conti, Federica Delia
Date Issued
March 11, 2011
Type
Doctoral Thesis
Abstract
Global change and in particular climate change affect terrestrial ecosystems in several ways, with effects only partially known. Several European areas will be more sensitive, like Mediterranean basin and Alps. In the Mediterranean Region air pressure and air surface temperature are going to increase, while precipitation patterns will show a decreasing trend with more drought periods. In the Alpine Region, air temperature rise and glaciers contraction registered in the latest years evidence the rapidity in the establishment of new conditions, to which alpine ecosystems couldn’t adapt. Feedbacks on ecosystems could show with diverse effects and it is necessary having specific instruments that allow to revealed them. Some trees, such as beech (Fagus spp.), in dendrological issue demonstrated a sensitiveness to environment conditions and are considered as good macroindicators. Also soil fauna communities could suffer changes. Soil fauna, in fact, answers to several environmental climate variables and a variation in moisture contents and temperature could alter species interactions, as well as influence directly on presence/absence of stress sensitive taxa, for example centipedes (Chilopoda), predatory arthropods frequent in forest ecosystems.
The studies were carry out in semi-natural Italian areas characterized by a low anthropogenic disturbance, on a North/South transect that includes North- West Alpine Region (Chalamy river valley, Aosta Valley), North Apennines Region (Upper Taro valley, Parma) and Latium Antiapennines Region (Vico Lake, Viterbo). Dominated European Beech and Turkey Oak forests were involved. The Turkey Oak forests were not found in the Alpine Region, thus they were characterized from soil chemical parameters and soil fauna composition point of view. In beech forests, chemical parameters (moisture, pH, O.M., organic C), dendrological analysis, soil fauna and centipedes community were determined. The soil fauna sampling consisted in three soil cores (100 cm2 per 10 cm in depth); microarthropods were extracted by using Berlese- Tüllgren funnels, observed, counted and identified to order level (class for myriapods), then QBS-ar index was calculated. Centipedes were collected combining three techniques: hand capture, pit fall traps and entomologic sieve. Dendrological sampling was carry out in Alpine and North Apennines Region during summer 2009 and 2010. For each site, 20-22 trees representative of the population were taken into account: stem core samples were obtained using Pressler's increment borer at height of 1.30 m from the ground.
The results allowed to describe current situation and vulnerability aspects could be identified. Tree-ring site chronologies allowed the evaluation of forest management and ecological limiting factors. Numerous taxa of soil microarthropods were found, even adapted groups associated to stability of soils such as proturans, pauropods and symphylans. QBS-ar values were characterized by high scores (more than 150 and frequently above 200) confirming soil “health” due to low rates of disturbances. By centipedes (73 individuals in the three sites) species, qualitative and quantitative composition of each community were underlined and climate change sensitive and keys species were identified. The
results were also used to define a “starting point” situation (T0) to compare future monitoring data in order to evaluate climate change in act.
Additional information
Dottorato di ricerca in Scienze e tecnologie per la gestione forestale e ambientale
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