Taxonomic, functional, and phylogenetic diversity of communities hosting Ionopsidium savianum (Brassicaceae) growing on serpentine and limestone substrates

Abstract

We analysed two different plant communities hosting Ionopsidium savianum (Brassicaceae), a species of EU interest included in the Habitats Directive 92/43/CEE annexes, for which specific studies on the ecology of communities where the species grows are lacking and more in-depth knowledge is needed. We examined two important sites of occurrence of this species in Tuscany with different soil types, namely limestone (Mt. Calvi) and serpentine (Mt. Pelato), to determine the structural and functional profile of the communities hosting this species in such different contexts. At each site, we surveyed the plant communities with I. savianum in ten 1 m2 quadrats to determine information on communities' species composition and total plant cover, as well as taxonomic (species richness, and Shannon H’ index), phylogenetic (phylogenetic diversity, mean nearest taxon distance and mean pairwise distance) and functional diversity (focusing on Rao’s Q, leaf functional traits and adaptive strategies community weighted mean). We took into account site location, soil type, slope aspect and microrelief as plot-level environmental factors. The two communities were highly diverging from multiple points of view. Differences were in species composition, richness and diversity, with Mt. Calvi hosting higher diversity. The indices of phylogenetic diversity were influenced significantly by site and microrelief, allowing the presence of peculiar niches occupied by the fern Asplenium ceterach. From the functional point of view, communities at Mt. Calvi showed a higher functional diversity and a higher specific leaf area. Plant height was influenced by the slope aspect and was higher on north-facing slopes. In terms of Grime’s adaptive strategies, the Mt. Pelato communities resulted to be more stress tolerant than those surveyed at Mt. Calvi. Here, a decrease in stress-tolerant strategy associated with an increase in ruderal strategy was detected in communities on north-facing slopes.

Relative contributions of taxonomic and functional diversity to the assembly of plant communities hosting endemic Dianthus species in a mountain steppe

“…A key ‘natural experimental’ system for comparing TD and FD involves relating these to environmental gradients of abiotic factors (particularly temperature, precipitation, and soil factors 8 – 10 ). However, studies comparing TD and FD environmental responses for plant communities tend to focus on woody vegetation 6 , 11 , while herbaceous mountain species and their communities are currently represented by the example of Ionopsidium savianum (Caruel) Ball ex Caruel (Brassicaceae) in Italy 12 , which is not an endemic or endangered species. Focus is required on the determinants of biodiversity for plant communities hosting endemic and endangered species, particularly for mountain habitats in which driving environmental gradients may be extreme.…”

Metal concentrations in invasive Ailanthus altissima vs native Fraxinus ornus on ultramafic soils: Evidence for higher efficiency in Ni exclusion and adjustments to Mg and Ca imbalance

“…As a result, biological communities inhabiting these soils are strongly selected and rich in species that have evolved adaptive traits including morpho‐functional and physiological strategies (Bettarini et al, 2020; Kruckeberg, 2002). These species are often edaphic endemics, being restricted to ultramafic soils over their entire range (obligate endemics), or may be facultative and also found on other soil types (Mugnai et al, 2022; Selvi, 2007; Stevanović et al, 2003). Hence, ultramafic plant communities across the world are of great biogeographical value and a valuable source of information about evolutionary processes, adaptive selection, and ecological speciation in plants (Harrison & Rajakaruna, 2011).…”