Impacts of invasive trees on alpha and beta diversity of temperate forest understories

Abstract

Despite good recognition of distributions and spread mechanisms of the three most invasive trees in Europe (Prunus serotina, Quercus rubra and Robinia pseudoacacia), their impacts on forest biodiversity are unevenly recognized. Most studies cover only taxonomic alpha diversity, and only a single study included functional and phylogenetic diversity. Using a set of 186 study plots in western Poland we assessed the impacts of these invasive tree species on the alpha and beta taxonomic, functional and phylogenetic diversity of understory vascular plants. Alpha diversity was higher in R. pseudoacacia forests and lower in Q. rubra forests compared to mature native forests. Compared to non-invaded plantations and forests, alpha diversity was higher in P. sylvestris plantations invaded by P. serotina, but lower in invaded nutrient-poor P. sylvestris forests. Alien species richness was higher and beta diversity was lower in forests invaded by P. serotina or R. pseudoacacia than in non-invaded forests. In contrast, beta diversity was higher in Q. rubra forests than in native forests. We proved that invaded forests differed from non-invaded forests in species composition, but not always with decreased alpha and beta diversity. Impacts of particular invasive species also depended on the reference ecosystem properties (here mature native forests, which did not always have the highest biodiversity), which is a source of inconsistency in previous studies, usually referring to single native ecosystem types.

Impacts of the Invasive Alien Carpobrotus spp. on Coastal Habitats on a Mediterranean Island (Giglio Island, Central Italy)

“…in favor of a small recolonization by native species. To our knowledge, the impacts of invasive species have been taken into account addressing almost exclusively the alpha component of diversity, with few examples of studies including the beta diversity component [ 40 , 52 ], of which only one addresses Carpobrotus spp. invasion in coastal areas [ 53 ].…”

Changes in Habitat Conditions of Invaded Forest Communities in Podunajská Nížina and the Impact of Non-Native Species on Biodiversity (SW Slovakia)

“…We believe that this is due to the following factors: (i) mosaic logging interventions in the forest stand, the number of species increases with the progress of successive series of vegetation development after logging; (ii) the noninvaded stands of the associated forest stand with a fallen layer are relatively poor in species and (iii) the invaded stands were also mapped on clearings with undergrowth of both forest species and numerous species of ruderal (R) strategy. Dyderski and Jagodziński (2021) referred to the mature native forests that have naturally low alpha diversity. However, these forests often contain rare and specialised species.…”

In search of a perfect trait set: A workflow presentation based on the conservation status assessment of Poland's dendroflora

“…After completing the database, we decided to continue the analysis on the set of traits that were available for at least 25% of the species. As some parts of the trait values were still missing and we did not want to exclude less represented species, we performed data imputation based on correlations among traits and between traits and phylogeny (Pyšek et al, 2015), using an approach analogous to Dyderski and Jagodziński (2021). As previously stated, we only imputed data for the traits that had at least 25% completeness with measured values obtained from databases and other sources used (CABI, 2020; Kaźmierczakowa et al, 2014, 2016; Rutkowski, 2006; Wild et al, 2019; Zieliński, 1987, 2004).…”