Floristic Inventory and Diversity of Urban Green Spaces in the Municipality of Assemini (Sardinia, Italy)

Urban greenery is a key component of green infrastructure, contributing to environmental sustainability and urban well-being. Between 2019 and 2020, a comprehensive inventory of ornamental flora was conducted in Assemini (Sardinia, Italy), documenting 198 vascular plant taxa, including 155 exotic, 41 native, and 2 cryptogenic species from 65 families. Among the exotic species, most were neophytes (63%), and 14% were archaeophytes. In terms of life forms, scapose phanerophytes, with a tree-like growth habit, dominated (45%), while Mediterranean and American chorotypes were the most represented, each accounting for 21%. A total of 7356 plants were recorded, comprising trees (61.3%), shrubs (32.3%), and climbers (5.7%), belonging to 90 shrub, 89 tree, and 19 climber taxa. The highest number of plants was found in "Green Areas" and "Schools", which also exhibited the greatest biodiversity, with 136 different taxa each. The most planted species were Quercus ilex, Nerium oleander, and Olea europaea. The survey also identified 21 allergenic, 36 toxic, and 35 mechanically harmful species, primarily located in "Green Areas" and "Schools". Biodiversity analysis using the Shannon Index revealed significant diversity, with Fabaceae, Apocynaceae, and Fagaceae emerging as the most represented families. These findings highlight the importance of plant inventories in urban green space management for sustainable planning. Well-maintained green spaces can enhance ecological resilience, improve public health, and promote social cohesion in future urban developments

A simple planning problem for COVID-19 lockdown: a dynamic programming approach

A large number of recent studies consider a compartmental SIR model to study optimal control policies aimed at containing the diffusion of COVID-19 while minimizing the economic costs of preventive measures. Such problems are non-convex and standard results need not to hold. We use a Dynamic Programming approach and prove some continuity properties of the value function of the associated optimization problem. We study the corresponding Hamilton-Jacobi-Bellman equation and show that the value function solves it in the viscosity sense. Finally, we discuss some optimality conditions. Our paper represents a first contribution towards a complete analysis of non-convex dynamic optimization problems, within a Dynamic Programming approach

HJB Equations and Stochastic Control on Half-Spaces of Hilbert Spaces

In this paper, we study a first extension of the theory of mild solutions for Hamilton–Jacobi–Bellman (HJB) equations in Hilbert spaces to the case where the domain is not the whole space. More precisely, we consider a half-space as domain, and a semilinear HJB equation. Our main goal is to establish the existence and the uniqueness of solutions to such HJB equations, which are continuously differentiable in the space variable. We also provide an application of our results to an exit-time optimal control problem, and we show that the corresponding value function is the unique solution to a semilinear HJB equation, possessing sufficient regularity to express the optimal control in feedback form. Finally, we give an illustrative example

Shrub Cover and Soil Moisture Affect Taxus baccata L. Regeneration at Its Southern Range

The effect of key ecological and anthropic factors on the recruitment of the common yew (Taxus baccata L.) in Sardinia (Italy) has been analyzed. After bibliographic and cartographic research, followed by field surveys, we found 232 sites where yew grows in Sardinia (as opposed to 69 previously reported in the literature). Among them, we selected 40 sites, located in 14 different mountain chains, characterized by a number of individuals ranging from 11 to 836 adult yews with an average diameter at breast height (DBH) from 13 to 130 cm. By means of generalized linear modeling, we investigated and weighted the effect of ecological, structural, and anthropic factors on the amount of T. baccata recruitment. Our analyses showed that stand recruitment was positively correlated to shrub cover and soil moisture. In particular, shrub cover had a stronger effect, clearly showing that a thicker shrub layer, both bushy and/or spiny, corresponded to a higher number of yew seedlings and saplings. Secondarily, moister sites had a higher number of seedlings and saplings, showing that habitat suitability improved with higher humidity. On the contrary, recruitment was negatively correlated to browsing (both from livestock and wild animals). Our data confirm that the presence of a protective layer of shrubs is a crucial factor for seedling and sapling survival, mostly in relation to protection from summer drought and the browsing of large herbivores. Finally, guidelines for the conservation and restoration of T. baccata communities, referred to as the EU priority habitat 9580* (Mediterranean Taxus baccata woods), have been outlined

The endemic vascular flora of Sardinia: a dynamic checklist with an overview of biogeography and conservation status

The vascular flora of Sardinia has been investigated for more than 250 years, with particular attention to the endemic component due to their phylogeographic and conservation interest. However, continuous changes in the floristic composition through natural processes, anthropogenic drivers or modified taxonomical attributions require constant updating. We checked all available literature, web sources, field, and unpublished data from the authors and acknowledged external experts to compile an updated checklist of vascular plants endemic to Sardinia. Life and chorological forms as well as the conservation status of the updated taxa list were reported. Sardinia hosts 341 taxa (15% of the total native flora) endemic to the Tyrrhenian Islands and other limited continental territories; 195 of these (8% of the total native flora) are exclusive to Sardinia. Asteraceae (50 taxa) and Plumbaginaceae (42 taxa) are the most representative families, while the most frequent life forms are hemicryptophytes (118 taxa) and chamaephytes (106 taxa). The global conservation status, available for 201 taxa, indicates that most endemics are under the ‘Critically Endangered’ (25 taxa), ‘Endangered’ (31 taxa), or ‘Least Concern’ (90 taxa) IUCN categories. This research provides an updated basis for future biosystematics, taxonomic, biogeographical, and ecological studies and in supporting more integrated and efficient policy tools

New national and regional Annex I Habitat records: from # 21 to #25

New Italian data on the distribution of the Annex I Habitats 3170*, 6110*, 91E0*, 9320, 9330 are reported in this contribution. Specifically, one new occurrence in Natura 2000 sites is presented and six new cells are added in the European Environment Agency 10 km × 10 km reference grid. The new data refer to the Italian administrative regions of Sardinia, Sicily and Umbria

Contribution to a new vascular flora of Sardinia (Italy): II (31-60)

Following the first contribution for a new, updated, and revised vascular flora of Sardinia, this work adds new data on the distribution of 30 taxa growing in the island. The treated taxa are both native and alien, and are characterised by their rarity, phytogeographical significance, endemicity, conservation issues, or novelty to Sardinia and Italy. These updates result from floristic research mostly conducted in South Sardinia but include several discoveries from the rest of the island. The first report of Commelina erecta, Ficus watkinsiana, Morus kagayamae, Opuntia elatior (casual alien species) in Sardinia is documented here. Additionally, Casuarina glauca and Robinia ×ambigua, are reported for the first time in Italy (casual alien). Moreover, the confirmation of Ajuga chamaepitys subsp. chamaepitys is here provided. Furthermore, new distributional data for 23 taxa, some of which known for their rarity, are gathered. Notably, Elatine hexandra and Cosentinia vellea subsp. bivalens, previously reported only once in recent years, along with Elatine alsinastrum and Halopeplis amplexicaulis, which were indicated only for a few sites. For others, an expansion or an improvement of their distribution range on the island is documented, as for rare endemics including Artemisia campestris subsp. variabilis, Bellium crassifolium, Borago morisiana, Dianthus cyathophorus subsp. cyathophorus, Filago tyrrhenica, Helicodiceros muscivorus, Limonium racemosum, Phleum sardoum, and Torilis nemoralis. New findings are also reported for Asplenium sagittatum, Ludwigia palustris, Malva lusitanica, Mandragora autumnalis, Persicaria decipiens, Piptatherum caerulescens, Rorippa sylvestris subsp. sylvestris, and Veronica anagalloides (rare or scattered native). In addition, new information on the distribution of Artemisia verlotiorum and Lycium ferocissimum (invasive alien species) is here reported. Finally, new data about some of the taxa recorded in the first contribution are added or modified

Contribution to a new vascular flora of Sardinia (Italy): I (1-30)

In the context of creating a new, updated, and revised vascular flora of Sardinia, this work contributes new data on the distribution of various taxa in the island. These include both native and alien taxa, which are characterized by their rarity, limited recognition, hytogeographical significance, potential issues, or novelty to Sardinia. These updates mostly result from floristic research primarily conducted in north Sardinia, with several discoveries in other sectors of the island. The first report of Convolvulus sabatius subsp. mauritanicus, Cyperus brevifolioides (naturalized) and Brachychiton populneus (casual alien) in Sardinia is documented here. Moreover, this study includes new distributional data for 27 taxa, some of which required confirmation. Notably, Trifolium clusii, previously considered doubtful in recent years, along with Fuirena pubescens and Silene inaperta, which were indicated for the southern part of Sardinia over thirty years ago and have not been reported elsewhere since. For others, an expansion or a better definition of their distribution range within the island is documented, as in the case of Chloris gayana, Digitaria ciliaris, Eragrostis curvula, Paraserianthes lophantha, Sporobolus indicus (naturalized alien species), Asparagus asparagoides, Cenchrus setaceus, Eclipta prostrata, Halophila stipulacea (invasive alien species), Allium sardoum, A. savii, Anthyllis barba-jovis, Asplenium marinum, Bellevalia romana, Butomus umbellatus, Cladium mariscus, Dianthus sardous, Dysphania botrys, Jacobaea maritima subsp. maritima, Leersia oryzoides, Nepeta foliosa, Nuphar lutea, Spirodela polyrrhiza, Utricularia australis (rare native)

Mediterranean plant germination reports – 5

This is the fifth issue of the series of germination reports from Mediterranean areas (sensu Med-Checklist). It comprises germination protocols for 18 taxa: Hieracium and Pilosella from South Italy by Di Gristina & al. (Nos. 103-106); Genista from Sardinia by Deplano & al. (No. 107); Antirrhinum, Anthyllis, Digitalis, Echium, Jasione, Nothoscordum, Silene and Verbascum by Martínez-Oliver & al. (Nos. 108-116); Dianthus, Helichrysum and Silene from Sicily by Scafidi & Salmeri (Nos. 117-120)

Global and Regional IUCN Red List Assessments: 2

In this contribution the conservation status assessment of six plant species according to IUCN categories and criteria are presented. It includes the assessment at global level of Charybdis glaucophylla Bacch., Brullo, D'Emerico, Pontec. & Salmeri, Euphorbia nicaeensis All. subsp. japygica (Ten.) Arcang., Hieracium australe Fr. subsp. australe, Limonium multiforme Pignatti, Onosma helvetica Boiss. em. Teppner subsp. lucana (Lacaita) Peruzzi, Aquaro & Cesca and the assessment at national level (Italy) of Lathyrus laxiflorus (Desf.) Kuntze subsp. laxiflorus