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Addenda to the lichen flora of the Ticino river valley (western Po Plain, Italy)
No full textThe Ticino river valley is a focal area for biodiversity in the western Po Plain (Northern Italy). Lichens have been collected by the author from 91 sites in the period 2011-2017. These collections and the few literature data published in the last decade have been summarized. Twenty-eight species (15 terricolous, 5 epiphytic, 3 lignicolous, 3 saxicolous, 1 epiphytic and lignicolous, 1 terricolous and epiphytic), mostly belonging to genus Cladonia, are reported here as addenda to the floristic list published 15 years ago by the Lombardy Ticino Park, which included 123 species. Many of the newly recorded species are interesting under a conservation or biogeographical standpoint
Dynamics and ecological functions of Cryptogam Soil Crusts (CSC) in planitial landscapes of continental-temperate regions
Full text linkDry grasslands and heathlands are important habitats for biodiversity conservation and host cryptogam soil crusts (CSC) that greatly contribute to ecosystem functioning.
This thesis aims at exploring:
the terricolous lichen diversity in dry habitats in a human-impacted lowland (Po Plain, N Italy);
the compositional patterns of CSC across dry grasslands and heathlands, also accounting for the dynamic stage of the vegetation (pioneer vs mature);
the effects of small-scale disturbances on the three main taxa found in cryptogam-rich dry grasslands (vascular plants, lichens, bryophytes);
the potential of CSC in delivering the ecosystem service of storing seeds of vascular plants, in the perspective of habitat restoration.
Diversity and dynamics were studied by means of vegetation surveys in circular plots, whose number was area-dependent, located along transects in each habitat patch (= 185 plots in 60 grasslands, 114 plots in 22 heathlands). The % cover of each plant, bryophyte and lichen was recorded, with environmental (soil pH and texture, vegetation structure, altitude, bare soil %), disturbance-related (human trampling, cattle and lagomorphs fecal pellets, wild boar scratches) and climate variables (mean annual temperature and precipitation).
The composition in lichens and bryophytes was compared among the 3 habitat types (3 groups) and between their dynamic stages (pioneer vs mature, 6 groups) to understand whether it is habitat- and stage-specific by means of NMDS, PERMANOVA and Indicator Species Analysis.
Drivers of cover and species richness of the 3 taxa were analyzed for dry grasslands by means of generalized linear models.
The seed storing function was studied taking 5 samples of CSC in 4 acidic grassland patches (= 20 samples), each sample taken at the centre of one plot surveyed in the previous spring. The samples were dryed, crumbled on sterile gardening soil in a controlled situation. All the germinated seedlings were identified and counted. Data were analyzed in comparison to data from the donor plots by means of Kruskal-Wallis test and linear regression, considering all the species and then native and non-native species separately .
33 terricolous lichen species were recorded, of which 13 of conservation concern.
In spite of the widespread presence of few common species and the generally low species richness, composition differs significantly between the 3 habitat types and between pioneer vs mature heathlands, less markedly between dynamic stages within each grassland type. Three well-characterized assemblages which include many species of conservation concern were found for both lichens and bryophytes. Cryptogam assemblages are influences also by rainfall, soil features and vegetation structure.
Increase of soil pH and disturbance by lagomorph fecal pellets have a negative effect on lichens, as well as their interaction (the negative effect of pellets is more evident at the increase of soil pH). Soil pH, fecal pellets and precipitation have a positive effect on bryophytes. Human trampling and fecal pellets have a negative effect on vascular plants, while increase of soil pH has a positive effect. The interaction of soil pH and pellets has an effect opposite than on lichens (the negative effect of pellets is more evident at the decrease of soil pH).
CSC are able to store and release vascular plant seeds which are viable and can germinate when placed in proper conditions. The number of species and individuals of vascular plants germinated from CSC is comparable to what recorded in nature in the donor plots. Native species richness was higher, while native species germinated with less individuals than non-native species.
These results are useful in addressing conservation towards the management and protection of all the lowland dry habitats, due to the differentiation among the cryptogam assemblages they host and to the presence of several species of conservation concern.Dry grasslands and heathlands are important habitats for biodiversity conservation and host cryptogam soil crusts (CSC) that greatly contribute to ecosystem functioning.
This thesis aims at exploring:
the terricolous lichen diversity in dry habitats in a human-impacted lowland (Po Plain, N Italy);
the compositional patterns of CSC across dry grasslands and heathlands, also accounting for the dynamic stage of the vegetation (pioneer vs mature);
the effects of small-scale disturbances on the three main taxa found in cryptogam-rich dry grasslands (vascular plants, lichens, bryophytes);
the potential of CSC in delivering the ecosystem service of storing seeds of vascular plants, in the perspective of habitat restoration.
Diversity and dynamics were studied by means of vegetation surveys in circular plots, whose number was area-dependent, located along transects in each habitat patch (= 185 plots in 60 grasslands, 114 plots in 22 heathlands). The % cover of each plant, bryophyte and lichen was recorded, with environmental (soil pH and texture, vegetation structure, altitude, bare soil %), disturbance-related (human trampling, cattle and lagomorphs fecal pellets, wild boar scratches) and climate variables (mean annual temperature and precipitation).
The composition in lichens and bryophytes was compared among the 3 habitat types (3 groups) and between their dynamic stages (pioneer vs mature, 6 groups) to understand whether it is habitat- and stage-specific by means of NMDS, PERMANOVA and Indicator Species Analysis.
Drivers of cover and species richness of the 3 taxa were analyzed for dry grasslands by means of generalized linear models.
The seed storing function was studied taking 5 samples of CSC in 4 acidic grassland patches (= 20 samples), each sample taken at the centre of one plot surveyed in the previous spring. The samples were dryed, crumbled on sterile gardening soil in a controlled situation. All the germinated seedlings were identified and counted. Data were analyzed in comparison to data from the donor plots by means of Kruskal-Wallis test and linear regression, considering all the species and then native and non-native species separately .
33 terricolous lichen species were recorded, of which 13 of conservation concern.
In spite of the widespread presence of few common species and the generally low species richness, composition differs significantly between the 3 habitat types and between pioneer vs mature heathlands, less markedly between dynamic stages within each grassland type. Three well-characterized assemblages which include many species of conservation concern were found for both lichens and bryophytes. Cryptogam assemblages are influences also by rainfall, soil features and vegetation structure.
Increase of soil pH and disturbance by lagomorph fecal pellets have a negative effect on lichens, as well as their interaction (the negative effect of pellets is more evident at the increase of soil pH). Soil pH, fecal pellets and precipitation have a positive effect on bryophytes. Human trampling and fecal pellets have a negative effect on vascular plants, while increase of soil pH has a positive effect. The interaction of soil pH and pellets has an effect opposite than on lichens (the negative effect of pellets is more evident at the decrease of soil pH).
CSC are able to store and release vascular plant seeds which are viable and can germinate when placed in proper conditions. The number of species and individuals of vascular plants germinated from CSC is comparable to what recorded in nature in the donor plots. Native species richness was higher, while native species germinated with less individuals than non-native species.
These results are useful in addressing conservation towards the management and protection of all the lowland dry habitats, due to the differentiation among the cryptogam assemblages they host and to the presence of several species of conservation concern
Terricolous lichens of the western Padanian Plain: New records of phytogeographical interest
No full textVery little is known of the earlier lichen flora of the Padanian Plain, the most heavily anthropized and industrialized part of Italy, which is currently extremely poor. Terricolous lichens in particular are the most sensitive to threats, and have almost totally disappeared from the western Padanian Plain. This paper reports new findings of 20 terricolous lichen species, several of which are rare or poorly known in Italy or are of some phytogeographical interest because they are found at lower altitudes than their usual distribution (i.e. Cladonia coccifera, Cladonia uncialis). In addition, Cladonia humilis is new for Lombardy and two other species, Cladonia portentosa and Stereocaulon condensatum, are reported for the second time in the same region. The significance of these species is discussed with regard to their historical records from the same area and their current altitudinal distribution; they were probably much more widespread in the past, but the decline and disappearance of their habitats in lowland areas have been followed by their own disappearance in many localities. A modification of the rarity status of some of these species in the considered phytoclimatic belts, based on the new records, is proposed
The genus Cladonia in western Liguria (Northern Italy)
No full textThe genus Cladonia (Cladoniaceae, Lecanorales, lichenized Ascomycota) has been surveyed in 44 sites in the province
of Imperia in western Liguria. Of 36 taxa recorded, Cladonia dimorpha and C. pseudopityrea are new to northern
Italy, and C. cryptochlorophaea, C. pleurota, C. polydactyla and C. rei are new to Liguria; interesting are also records
provided for C. arbuscula, C. incrassata and C. mediterranea. The most widespread species are C. chlorophaea, C.
pyxidata, C. ramulosa and C. rangiformis. Data on ecology and chemistry of the species are given
Epiphytic lichens of woodland habitats in the lower Ticino river valley and in the “Bosco Siro Negri” Integral Nature State Reserve (NW Italy)
Full text linkEpiphytic lichens were surveyed in the “Bosco Siro Negri” Integral Nature State
Reserve (province of Pavia, Lombardy, NW Italy), which hosts a well-preserved fragment of
oak-elm floodplain forest (Natura 2000 Habitat 91F0). The core woodland fragment hosted
only four species on the tree boles, i.e. Lepraria finkii plus the forest specialists Coenogonium
pineti, Diarthonis spadicea, and Opegrapha vermicellifera. An additional eight nitro- and
photophytic species were recorded on the highest twigs of the canopy. The whole Reserve,
including the neighbouring degraded woodlands and poplar plantations, hosted 27 epiphytic
lichen taxa. The lower Ticino River valley between Vigevano and Pavia, in which the Reserve
is located, was surveyed for epiphytic lichens in an additional 45 sites, including 15 wellpreserved
oak-elm/hornbeam woodlands (Habitat 91F0), 15 degraded broadleaved woodlands
with high occurrence of black locust and 15 poplar plantations. Overall, 32 species were
recorded. Well-preserved woodlands had a lower species richness, but they hosted forest
specialists not occurring in the other two habitats. Graphis pulverulenta and Lecania cyrtellina
are new to Lombardy. Anisomeridium polypori, Diarthonis spadicea, Lecanora expallens and
Pseudoschismatomma rufescens are reported from Lombardy for the second time
Contribution to the knowledge of lichen flora of inland sand dunes in the western Po Plain (N Italy)
No full textHabitat loss, extinction debt and climate change threaten terricolous lichens in lowland open dry habitats
No full textImpact of an invasive herbivore and human trampling on lichen-rich dry grasslands: Soil-dependent response of multiple taxa
No full textDry grasslands are listed among the habitats of conservation concern in Europe. Here, based on a multitaxon approach including vascular plants, bryophytes and lichens, we explored the effects of small-scale disturbance on lichen-rich dry grassland vegetation by surveying 60 sites across the Po Plain (Northern Italy). In particular, we evaluated the impact of human trampling and fecal pellet deposition by the alien invasive herbivore Sylvilagus floridanus. We found a soil-dependent response of multiple taxa to the impact of the herbivore. For plants, beside a negative effect of trampling, the interaction between fecal pellet amount and soil pH indicates that the negative effect of the invasive herbivore is stronger on acidic soils. Bryophyte cover increased with increasing soil pH, annual rainfall and fecal pellet, while it was not affected by trampling. Lichen richness and cover decreased with increasing soil pH. The marginal interaction between soil pH and amount of fecal pellet indicates that the more negative effects on lichens may be expected on calcareous soils. Trampling did not affect lichen patterns and the rainfall gradient marginally affected lichen cover with a negative effect. Lichen species richness is also negatively affected by increasing vascular plant cover. The main implications of this study for improving conservation are: (1) conservation practices should be tailored to organism and substrate type; (2) bryophyte and lichen diversity patterns are influenced also by climatic conditions, suggesting that the impact on these organisms may be exacerbated by climate change; and (3) strict conservation, even through active exclusion of wild fauna, of the most species-rich sites should be recommended, even if previous literature and the negative plant cover-lichen richness relationship found in this study indicate that moderate mechanical disturbance could be a practical tool to enhance cryptogams
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