Ecological niche modeling of Schinus molle reveals the risk of invasive species expansion into biodiversity hotspots

Abstract

Invasive species need a closer look on the threats they may cause to the environment, mainly considering the scenario of climatic changes predicted for the next decades. Schinus molle is a pioneer tree native from South America, reported as an important invasive species in four continents. Using ecological niche modeling we show that a wide area over the world is propitious for S. molle establishment under current climatic conditions, including 14 of the 25 world's biodiversity hotspots. Current projections of climate changes suggest scenarios implying the rise of areas favorable for S. molle expansion. Therefore, particular attention should be taken in regions where it was introduced, while approaches for long-term intervention may be necessary for regions of S. molle natural occurrence if its expansion threatens other native species. However, the natural dynamic of the ecosystems should be studied and contemplated in such regions.

A global assessment of the potential distribution of naturalized and planted populations of the ornamental alien tree Schinus molle

“…Factors relating to temperature were the most important for defining the potential distribution of this species. In this regard, our results confirm those of earlier studies on S. molle (Iponga et al 2008; Lemos et al 2014Lemos et al , 2019Ramírez-Albores et al 2020;Guerra-Coss et al 2021). Schinus molle can be established easily in arid and semiarid climates in Mexico, California, Australia, and South Africa, probably because of the similarities in the climate in their native range (e.g., Richardson and Thuiller 2007 [figure 2] for South Africa).…”

“…The Global planted model predicts large areas of suitable habitat areas in the western and Mediterranean regions of Europe and Africa, the Brazilian Atlantic coast, and the Pampa region of Argentina, Brazil, and Uruguay, showing a high proportion of stable populations and few sink populations compared to the Global naturalized model. This pattern is similar to that reported by Richardson et al (2010) and Lemos et al (2019), who mentioned that the largest areas of suitable habitat for the establishment of S. molle are subsidized by humans. In general, sink populations were found in tropical and cold climates as well as deserts which represent stressful and extreme temperatures.…”

“…Therefore, we suggest that it is plausible in this case that the geographical range of S. molle can be further extended as humans continue to use this species for ornamental and forestry purposes in urban and rural environments, thereby modifying the fundamental niche of S. molle (Ingeloff et al 2017;Qiao et al 2017). However, this could also be established by natural processes as it occurs in the Brazilian Atlantic coast and the Pampa region (Lemos et al 2014(Lemos et al , 2019.…”