Niche Heterogeneity and Old-Growth Forests Conservation Value

Abstract

Vascular plants understorey of an old-growth beech forest was compared to a managed stand, similar for biogeographical, climatic and abiotic features. Parametric tests and accumulation and rarefaction curves were used to compare the stands in terms of vascular plant diversity at stand level and among sampling units. The sampled understorey species were characterized in terms of functional traits and Ellenberg’s indicator values; next, we calculated four different pairwise plot-to-plot dissimilarity matrices based on: 1. species presence/absence, 2. cover values, 3. functional traits and 4. Ellenberg’s indices. We applied a permutational multivariate extension of ANOVA to test whether the forest stands significantly differ in the considered features. Furthermore we used fourth corner analysis to highlight which single functional trait is significantly associated to each stand. Although not richer at plot level the old-growth stand resulted more diverse both at stand level and in terms of among-plots diversity than the managed one. All the comparisons performed through permutational multivariate ANOVA showed significant differences, with the exception of the one based on Ellenberg’s indices. From a functional and ecological perspective in the old-growth forest we noted: 1. a relative increase of hemicryptophyte species with limited dispersal abilities (ant- dispersed or non specialized); 2. a decrease in early-flowering geophytes; 3. a parallel increment in small seeded, wind-dispersed species adapted to relatively open and bright conditions (gaps). Our results suggest that in the old-growth stand the high vertical and horizontal structural heterogeneity of the canopy modulates the ecological conditions at the forest floor and increases the environmental heterogeneity. This mechanism is likely to allow the coexistence of a higher number of species, with different ecological requirements

An index of structural complexity for Apennine beech forests

“…As an additional dataset, we selected 10 beech-dominated stands in central Italy with old-growth features (such as high density of large living trees, high amount of deadwood, uneven-aged structure), whose high structural heterogeneity was previously reported in several studies (Piovesan et al 2005, Burrascano et al 2008, Lombardi et al 2010, Sabatini et al 2010, 2014, Travaglini et al 2012. Information on location, climate, underlying bedrock and time since last disturbance of these stands is provided in Tab.…”

“…To identify the suite of attributes to include in this index of structural heterogeneity, we first explicitly defined the main sources of structural complexity commonly reported for beech natural forests in Italy and southern Europe. We considered old-growth condition as the reference state, given that late successional forests, especially old-growth stands, are known to have a high horizontal and vertical structural diversification (Piovesan et al 2005, Bianchi et al 2011, Motta et al 2011, Travaglini et al 2012, Rugani et al 2013, Sabatini et al 2010, 2014.…”

Stand structure attributes in potential Old-Growth Forests in the Apennines, Italy

“…"Fonte Novello" area was compared by SabatInI et al (2010) with beech forest of Tassete -Grotta delle Fosse (a high forest located on the eastern slope of Monte Cima Alta, at the head of Rio San Giacomo valley). This area was chosen for its similarity and closeness (5.6 km) to Fonte Novello stand.…”

Characterization, structure and genetic dating of an old-growth beech-fir forest in the northern Apennines (Italy)

“…The interest on old-growth forest studies has been recently renewed by national projects aimed to increase the knowledge on old-growth forest stands in the Alps and Apennines (Blasi 2010;Chirici & Nocentini 2010;Piovesan et al 2010). In these projects, the following topics were addressed: ecology ) and stand structure (Ciancio et al 2010;Iovino et al 2010;Manes et al 2010;Palombo et al 2010;Piovesan et al 2010), deadwood (Burrascano et al 2008;Lombardi et al 2010;Motta et al 2010), vascular flora (Sabatini et al 2010), lichens and bryophytes (Brunialti et al 2010;Potenza & Fascetti 2010;Ravera et al 2010), carbon stock (Piovesan et al 2010), genetic diversity (Vettori et al 2010), monitoring systems Corona et al 2010;Di Paolo et al 2010) and, finally, possible indications from old-growth studies in supporting forest management and planning in areas with long standing human impact (Nocentini 2010).…”