Variations in leaf litter decomposition explain invasion success of Broussonetia papyrifera over confamilial non-invasive Morus alba in urban habitats

Abstract

In urban environments, anthropogenic influences play an important role in determining the distribution of woody flora and consequently, the propagation of woody invaders. Land-use changes and disturbances associated with urbanization may intensify different invasive aspects of a species. Studying the extent by which invasive species vary from non-invasive species can strengthen our understanding of urban invasions. In this study, we compared leaf litter decomposition between two confamilial exotics, an invasive Broussonetia papyrifera, and a non-invasive Morus alba (both belonging to family Moraceae), growing in urban habitats. Senescent leaves of both the species and soil were collected from five study sites in Chandigarh, India. Litterbags filled with 10 g leaves each were placed in pots containing the soil collected from respective study sites. Mass remaining, decomposition constant, and soil elemental composition were determined after periodic harvesting of the pots. Decomposition was completed within 180 days in B. papyrifera and 330 days in M. alba. Initially, the decomposition rate was low in B. papyrifera; however, a rapid degradation occurred after 90 days. Species, time, and their interaction significantly affected most of the elements in soil, whereas the effect of habitat was not significant. The faster decomposition rate in B. papyrifera may result in greater turnover of nutrients over a shorter time span, thereby, favoring its colonization in the invaded regions. The difference in litter decomposition process explains the invasion success of B. papyrifera over its confamilial species, M. alba, in urban habitats.