Do Habitats Show a Different Invasibility Pattern by Alien Plant Species? A Test on a Wetland Protected Area

Abstract

<jats:p>Biological invasions are deemed to be the second most important global driver of biodiversity loss, right behind habitat destruction and fragmentation. In this study, we aimed at testing if community invasibility, defined as the vulnerability to invasion of a community, could be associated with the characteristics of a given habitat, as described by the composition and structure of its native species. Based on a probabilistic sampling of the alien flora occurring in the temperate wetland Lake Doberdò (Friuli Venezia Giulia region, NE Italy) and using a null-model-based approach, the observed occurrence of Invasive Alien Species (IAS) within sampling units was randomized within habitats. While testing the degree of invasibility for each habitat within the wetland, our null hypothesis postulated that habitats are equally invaded by IAS, as IAS can spread homogeneously in the environment thanks to their plasticity in functional traits that makes them able to cope with different ecological conditions. The obtained results comparing observed IAS frequencies, abundance and richness to those obtained by the null model randomizations show that, for all habitats, invasion was selective. Specifically, a marked preference for habitats with an intermediate disturbance level, a high nutrients level and a medium-high light availability was observed, while an avoidance was detected for habitats characterized by lower levels of nutrients and light availability or extreme conditions caused by prolonged submersion. This method allows us to provide useful information using a simple-to-run simulation for the management of the IAS threat within protected areas. Moreover, the method allows us to infer important ecological characteristics leading to habitat invasion without sampling the environmental characteristic of the habitats, which is an expensive operation in terms of time and money.</jats:p>

Determining Plant Diversity within Interconnected Natural Habitat Remnants (Ecological Network) in an Agricultural Landscape: A Matter of Sampling Design?

“…Since ENs are often modeled on the basis of species-habitat interactions and designed based on graph theory [66,67], it is extremely important to join biological data in the graph's early construction stage [44] to confirm the distribution of the habitat types in the area and their composition in terms of plant communities, as they are the primary component for habitat types determination [31][32][33][34] and the basis on which the interaction species-habitat are set up.…”

“…The sampled EN is composed of numerous PAs and biotopes, as well as several patches of semi-natural and natural habitats in an agricultural landscape matrix. These habitat types, forming the nodes of the EN, consist mainly of wetlands, linked to the presence of rivers and fens, which are well-known for their ecological role and for the high levels of biodiversity [44]. These environments are usually underrepresented in EN studies and the few studies concerning wetlands tend to give more weight to animal diversity instead of plant diversity [45].…”

Practice Must Be Backed up by Theory! A Special Issue on Plant Community Ecology

“…Challenging our comprehension of the mechanisms that underlie the invasibility of Invasive Alien Species (IAS) can help us to cope with this key threat to biodiversity [18]. In particular, Tordoni et al [3] suggested that functional niche divergence may foster community invasibility; resident native communities more susceptible to invasion are those which, on average, showed a combination of functional traits (higher resource acquisition capacity and lower drought resistance) coupled with an apparently reduced water-use efficiency.…”

Biodiversity and Litter Breakdown in a Karstic Freshwater System (Doberdò Lake, Northeast Italy) in Relation to Water Level Fluctuations and Environmental Features

“…Smith et al [5] studied the influence of habitat structure and flow permanence on invertebrate community within a karstic spring system; Tanaka et al [6] analyzed macrobenthic invertebrate succession during leaf litter breakdown in perennial karstic rivers in western Brazil. However, regarding karstic ephemeral lakes, most of the studies are focused on vegetation [3,23], productivity [8,13], decomposition processes [10,24] and hydrology [25][26][27].…”