Factors influencing the local scale colonisation and change in density of a widespread invasive plant species, Lantana camara, in South India

Abstract

Identifying factors that underlie invasive species colonisation and change in density could provide valuable insights into the mechanisms of biological invasions and for invasive species management. We examined a suite of factors potentially influencing the landscape-level invasion of Lantana camara L., one of the most ubiquitous invasive species in South Asia. These factors included disturbance factors like forest fires, historical habitat modification, and edge effects, in addition to factors like propagule pressure and habitat suitability. We examined the relative importance of these factors on the colonisation and change in density of L. camara in the Biligiri Rangaswamy Temple Tiger Reserve, Western Ghats, India. We used extensive (1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008) datasets tracking the presence and abundance of L. camara and combined these with corresponding data on disturbances, propagule pressure, and habitat suitability. We used an information-theoretic model selection approach to determine the relative importance of each factor on the colonisation and change in density of L. camara. Colonisation was mainly a function of proximity to already established populations (i.e. propagule pressure), whereas increase in L. camara density appeared to be constrained by high fire frequency. Research and management efforts need to recognize the multidimensional nature of mechanisms underlying L. camara's success during different invasion phases when strategizing interventions to mitigate its effects.

Long‐term Spartina alterniflora invasion simplified soil seed bank and regenerated community in a coastal marsh wetland

“…In addition, the species density in the S.AS was higher at the 0–5 cm soil depth than those under other vegetation types, while at 5–10 cm soil depth was the lowest, which suggested that S.AS tended to concentrate seeds on the 0–5 cm soil depth compared with those of other communities. The high density of seeds of S. alterniflora under its own community tended to help to consolidate its colonization and promote its further invasion (Sundaram et al, 2015). Results also showed that the seed species richness and density in the soil seed banks was higher than that of aboveground vegetation, indicating that there would be more potentiality of regeneration from the soil seed banks if the aboveground vegetation were destroyed or seriously damaged.…”

Relationship of alien species continues in a foreign land: The case ofPhytophthoraand AustralianBanksia(Proteaceae) in South African Fynbos

“…But the fundamental question of why some introduced species become more abundant and widespread than others still remains only partially answered (Keane & Crawley, 2002; Kolar & Lodge, 2001; van Kleunen et al, 2010). There are various factors that influence the degree of invasion in an ecosystem; these include—among others—fires, historical habitat modification, propagule pressure, release from herbivores, human usage, pollinators, and habitat suitability (Geerts & Adedoja, 2021; Geerts et al, 2016; Geerts, Botha, et al, 2013; Honig et al, 1992; Mangachena & Geerts, 2019; Sundaram et al, 2015). Many hypotheses have been put forward to explain these phenomena (reviewed in Catford et al, 2009).…”