Diversity patterns of alien and native plant species in Trieste port area: exploring the role of urban habitats in biodiversity conservation

Abstract

Nowadays, urban areas play a crucial role in biodiversity conservation and habitat protection despite the constant pressures on which these habitats are subjected. They may even host relatively new plant communities due to the peculiar ecosystem where they vegetate. The port of Trieste (NE Italy) is characterized by a mixed mosaic of intensely human impacted areas (where commercial activities are still ongoing) flanked by abandoned areas where vegetation persists or has spontaneously recovered. In this study, we sampled the whole port area through a stratified random sampling by placing multiscalar nested plots in four different habitats (strata) previously identified by photo-interpretation. Plant species richness and abundance were assessed in each plot. Each species was then classified as native or alien and patterns of species richness and complementarity were compared among habitats. Results show that there is a significant difference in species richness patterns among habitats, while observed patterns are likely to vary at different spatial scales. As expected, urban plots account for most of the alien species in the sampling, while wooded plots cope better with invasion, accounting for a lower alien/native ratio. These results highlight how habitat diversity enhances biodiversity in urban areas and how it could provide an effective filtering effect able to reduce the spread of alien species. In addition, we provide further evidence for the use of multi-scale approaches in order to study the complex relationships between spatial heterogeneity and plant species richness

Ecological drivers of plant diversity patterns in remnants coastal sand dune ecosystems along the northern Adriatic coastline

“…This indicates that alien species tend to share species composition increasing the scale of analyses. A similar pattern has also been described in Tordoni et al (2017) for a coastal urban context. Although the richness values of native and alien species were correlated at the plot scale, it has been clearly demonstrated that most likely it is the beta diversity of both species groups which regulate equilibrium in the plant community.…”

Functional Divergence Drives Invasibility of Plant Communities at the Edges of a Resource Availability Gradient

“…Biotic interactions (i.e., competition and facilitation) may become more and more important along the subsequent stages of the invasion continuum [31]. One of the main consequences of the invasion processes could be the disruption and homogenization of the native resident community [92][93][94][95][96], resulting in a loss of species and a reduction in the functional space [42]. Probably, accounting for phylogenetic signal and intraspecific trait variation along with the use of long-term experiments [78] may help to comprehensively understand invasion dynamics, even though not all traits are phylogenetically conserved.…”

Effect of Invasive Alien Species on the Co-Occurrence Patterns of Bryophytes and Vascular Plant Species—The Case of a Mediterranean Disturbed Sandy Coast

“…In the Mediterranean Basin, well preserved coastal habitats became rarer as the anthropogenic pressure increased, mainly consisting in touristic settlements, habitat fragmentation and inappropriate land management, such as reforestation with alien species [11,[18][19][20][21]. Invasive alien species (IAS) are recognized as an important threat to biodiversity worldwide [22] and especially in rare and extreme environments (such as alpine zone or isolated islands, [23][24][25]). On dune ecosystems, in particular, IAS alter the structure of native communities in different ways: reducing functional, phylogenetic and taxonomic diversities and excluding closely related and ecologically similar taxa [26][27][28][29][30].…”