Soil Nutrients Can Influence Exotic Species Richness in Urban Areas: A Case Study from the City of Kolkata

Abstract

Urbanization contributes to extensive land use changes and environmental degradation which may influence changes in soil properties. These abiotic changes may aggravate invasions and favour the distribution and number of invasive species in urban areas which could negatively impact biodiversity. This case study was, therefore, undertaken in the metropolitan city of Kolkata to assess the existing plant species richness (both native and exotic) and to determine the relative role of some soil physico-chemical parameters on species richness. Plant species were recorded and soil samples were collected from each study site. The total species richness ranged from 4 to 25 with 50% of sites having a median number of 11 species. The presence of at least 3 or more invasive species was observed in >80% of sites. The mean and median values of soil parameters showed considerable variation in soil properties between sites. Urban soils had elevated pH values and higher available N, P and Ca. Soil available N appeared to be significantly correlated with both total species and exotic (including invasive) species richness while available phosphorus showed significant correlation with only exotic species richness. The GLM Poisson log-linear models showed a significant positive relationship of soil N with total species richness and exotic richness including invasive species richness in the study area.

Restoration Contributes to Maintain Ecosystem Services and Bio-Cultural Linkages Between Wetlands and Local Communities: a Case from a Botanical Diversity Hotspot in Japan

“…The actual EC values of seeping water at the experimental site after the conifer removal have been 17–25 μS/cm, and total N and P were 1.2 mg/L and < 0.05 mg/L, respectively (I. Saeki, unpublished data). Exotic plants are known to favor nitrogen-rich sites (Chatterjee and Dewanji 2019 ). It is often difficult to restore wetland vegetation when nitrogen and phosphorus levels are high because this can increase the productivity of invasive species (van der Hoek and Braakhekke 1998 ; Zedler 2000 ).…”