Ancestral origins and invasion pathways in a globally invasive bird correlate with climate and influences from bird trade

Abstract

Invasive species present a major threat to global biodiversity. Understanding genetic patterns and evolutionary processes that reinforce successful establishment is paramount for elucidating mechanisms underlying biological invasions. Among birds, the ring-necked parakeet (Psittacula krameri) is one of the most successful invasive species, established in over 35 countries. However, little is known about the evolutionary genetic origins of this species and what population genetic signatures tell us about patterns of invasion. We reveal the ancestral origins of populations across the invasive range and explore the potential influence of climate and propagule pressure from the pet trade on observed genetic patterns. Ring-necked parakeet samples representing the ancestral native range (n = 96) were collected from museum specimens, and modern samples from the invasive range (n = 855) were gathered from across Europe, Mauritius and Seychelles, and sequenced for two mitochondrial DNA markers comprising 868 bp of cytochrome b and control region, and genotyped at 10 microsatellite loci. Invasive populations comprise birds that originate predominantly from Pakistan and northern areas of India. Haplotypes associated with more northerly distribution limits in the ancestral native range were more prevalent in invasive populations in Europe, and the predominance of Asian haplotypes in Europe is consistent with the higher number of Asian birds transported by the pet trade outside the native range. Successful establishment of invasive species is likely to be underpinned by a combination of environmental and anthropogenic influences.

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.…”

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, by comparing the proportion of Asian/African haplotypes with the proportion of Asian/African birds imported in each country, Jackson et al . () found that the proportion of Asian genes was higher than expected in four countries, lower than expected in two countries, and nearly identical in one country. As authors recognized, these apparent contradictions might arise from the fact that trade data are available at the country level, while only particular populations were genetically screened within each country.…”

“…Environmental suitability, trade of this species and its invasiveness greatly vary among countries, thus allowing a broader examination than the subset of successfully invaded countries considered by Jackson et al . (). Our study demonstrates a framework to disentangle the contribution of environmental suitability, propagule origin and pressure, valid for many other globally traded and invasive organisms.…”

Introduction History, Impacts, and Management of House Sparrows in North America

“…In fact, the Invasive Species Compendium (2012) reports that 76 countries currently have rose-ringed parakeets or had them in the past. Of the four recognized subspecies of Psittacula krameri (two are from sub-Saharan Africa, including Senegal, Uganda, Sudan, Somalia, and Ethiopia; and two are from Asia, including India, Sri Lanka, Nepal, and Pakistan), the majority of the invasive rose-ringed parakeets are from northern India and Pakistan (P. k. borealis; Jackson et al 2015). Temperature apparently provides some limitation to where they can become established (Roscoe et al 1976;Butler 2005), yet they have successfully colonized tropical, subtropical, and temperate environments.…”