Invasion success of a global avian invader is explained by within‐taxon niche structure and association with humans in the native range

Abstract

Aim To mitigate the threat invasive species pose to ecosystem functioning, reliable risk assessment is paramount. Spatially explicit predictions of invasion risk obtained through bioclimatic envelope models calibrated with native species distribution data can play a critical role in invasive species management. Forecasts of invasion risk to novel environments, however, remain controversial. Here, we assess how species’ association with human‐modified habitats in the native range and within‐taxon niche structure shape the distribution of invasive populations at biogeographical scales and influence the reliability of predictions of invasion risk. Location Africa, Asia and Europe. Methods We use ~1200 native and invasive ring‐necked parakeet (Psittacula krameri) occurrences and associated data on establishment success in combination with mtDNA‐based phylogeographic structure to assess niche dynamics during biological invasion and to generate predictions of invasion risk. Niche dynamics were quantified in a gridded environmental space while bioclimatic models were created using the biomod2 ensemble modelling framework. Results Ring‐necked parakeets show considerable niche expansion into climates colder than their native range. Only when incorporating a measure of human modification of habitats within the native range do bioclimatic envelope models yield credible predictions of invasion risk for parakeets across Europe. Invasion risk derived from models that account for differing niche requirements of phylogeographic lineages and those that do not achieve similar statistical accuracy, but there are pronounced differences in areas predicted to be susceptible for invasion. Main conclusions Information on within‐taxon niche structure and especially association with humans in the native range can substantially improve predictive models of invasion risk. To provide policymakers with robust predictions of invasion risk, including these factors into bioclimatic envelope models is recommended.

Avian SDMs: current state, challenges, and opportunities

“…The general picture that emerges from these studies is that differences between native and invasive climate niches are prevalent, but they mainly arise through a partial occupation of native niche conditions in the invasive range. Cases of niche expansion have been reported, too, and studies on ring-necked parakeets Psittacula krameri suggested that species with prior-adaption to human-dominated habitats in the native range, intra-specific niche differences and differential propagule pressure may expand their niche into climates not occupied across their native ranges (Jackson et al 2015, Strubbe et al 2015a, Cardador et al 2016. One other study (Ancillotto et al 2015) suggested that interspecific interaction with previously established ring-necked parakeets may have facilitated niche expansion of invasive Alexandrine parakeets P. eupatria in Europe.…”

Mechanistic and Correlative Models of Ecological Niches

“…' However, correlative approaches have limited use in pinpointing fine-grain, individual-level tolerance limits. When local adaptation in niche-relevant dimensions has occurred, correlative models cast at the level of the species will overestimate the niche of any single population (whereas mechanistic models based on single populations will tend to underestimate niches in the same circumstances), and conversely niches estimated for single populations or subsets of species' overall distributions may underestimate the full breadth of the niche (Peterson & Holt 2003;Strubbe et al 2015) or indeed fail to achieve a predictive model at all (Owens et al 2013). Finally, very clearly, the vagaries of the sampling of biodiversity (e.g., spatial bias to accessible areas, incomplete sampling across an area, incomplete detectability of individuals) will have considerable potential to translate into new biases and problems in model outcomes (Hijmans 2012;Kramer-Schadt et al 2013;Boria et al 2014).…”

Combining trade data and niche modelling improves predictions of the origin and distribution of non‐native European populations of a globally invasive species

“…Second, Jackson et al . () found that Asian haplotypes were more prevalent in invasive populations in Europe, being consistent with niche distribution modelling results (Strubbe et al ., ), but also found a higher proportion (75%) of Asian individuals imported in the seven European countries studied (Jackson et al ., ). However, by comparing the proportion of Asian/African haplotypes with the proportion of Asian/African birds imported in each country, Jackson et al .…”

“…However, Strubbe et al . () did not consider the role of propagule pressure, which may confound the actual role of niche similarity in shaping current invasion ranges (Colautti et al ., ). Second, Jackson et al .…”

“…First, Strubbe et al . () demonstrated that niche requirements varied between the African and Asian phylogenetic lineages of the species, making Asian individuals more suitable to invade the new European environments. However, Strubbe et al .…”