Inconsistencies among secondary sources of Chukar Partridge (<i>Alectoris chukar</i>) introductions to the United States

Moulton, Michael P.; Cropper, Wendell P.; Broz, Andrew J

doi:10.7717/peerj.1447

Cited by 6 publications

(5 citation statements)

References 35 publications

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“…Moreover, the data used on this analysis included a large number of Galliform birds (20.2% of 1,530 records). Managers often introduced these birds into previously established populations (Banks, 1981; Moulton, Cropper & Broz, 2015, 2018; Moulton & Cropper, 2014b).…”

Section: Discussionmentioning

confidence: 99%

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Propagule pressure does not consistently predict the outcomes of exotic bird introductions

Moulton

Cropper

2019

PeerJ

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Some have argued that the role of propagule pressure in explaining the outcomes of bird introductions is well-supported by the historical record. Here, we show that the data from a large published database (including 832 records with propagule information) do not support the conclusion that propagule pressure is the primary determinant of introduction success in birds. A few compendia of historical reports have been widely used to evaluate introduction success, typically by combining data from numerous species and introduction locations. Very few taxa, other than birds, have usable spatially explicit records of introductions over time. This availability of data inflates the perceived importance of bird analyses for addressing factors related to invasion success. The available data allow limited testing of taxonomic and site-level factors of introduction outcomes. We did find significant differences in effort and success probabilities among avian orders and across highly aggregated spatial regions. As a test of a standard and logical expectation of the propagule pressure hypothesis, we concentrated on introductions with the smallest propagules, because it is for these the hypothesis is most likely to be correct. We analyzed the effect of numbers released in small propagules (two through 10) for 227 releases. Weighted linear regression indicated no significant effect of propagule size for this range of release size. In fact, the mean success rate of 28% for propagules of 2–10 isn’t significantly different than that of 34% for propagules of 11–100. Following the example of previous analyses, we expanded the statistical test of propagule pressure to include the full range of release numbers. No significant support for the propagule pressure hypothesis was found using logistic regression with either logit or complementary log-log link functions.

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Section: Discussionmentioning

confidence: 99%

“…We adopted this procedure because of the substantial uncertainties in propagule sizes per release (Moulton, Cropper & Broz, 2015). Additionally, previous analyses that used extremely large releases compiled over many species, over long spans of time and spatial scale inflate the number of degrees of freedom leading to spurious results.…”

Section: Methodsmentioning

confidence: 99%

Propagule pressure does not consistently predict the outcomes of exotic bird introductions

Moulton

Cropper

2019

PeerJ

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“…The native distribution range of this species extends from the Balkans to eastern Asia [12], with 14 morphological subspecies [13] clustering into two well-distinct genetic lineages forming an eastern and a western clade separated by mountain ranges from Altay to Himalayas [14,15]. Eastern clade chukars are also raised in farms for hunting and meat production [16,17]. Moreover, European game farms breed A. rufa x A. chukar [18][19][20] and A. graeca x A. chukar producing hybrids [11,21] that are released into the wild for shooting purposes with the aim of supplementing natural populations.…”

Section: Introductionmentioning

confidence: 99%

Evidence for Genetic Hybridization between Released and Wild Game Birds: Phylogeography and Genetic Structure of Chukar Partridge, Alectoris chukar, in Turkey

et al. 2022

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The Chukar Partridge (Alectoris chukar, Galliformes) is one of the most important game birds in its native range, spanning from the Balkans to eastern Asia, and the regions of Europe, North America and New Zealand where it was introduced. Previous studies found two main genetic lineages of the species forming an eastern and a western clade. Chukar Partridges are raised in game farms and released to supplement natural populations for shooting in the USA, Canada, Greece, and Turkey. To explore intraspecific genetic structure, phylogeography, and possible genetic admixture events of A. chukar in Turkey, we genotyped individuals from fourteen wild and five captive populations at two mitochondrial and ten microsatellite DNA loci in. Wild and farmed Chukar Partridge samples were analyzed together to investigate possible influences of intraspecific hybridizations. We found that the farmed chukars, which mainly (85%) cluster into the eastern clade, and wild ones were genetically distinct. The latter could be separated into six management units (MUs), with partridges from Gökçeada Island in the Aegean Sea forming the most divergent population. Intraspecific hybridization was detected between wild and captive populations. This phenomenon causes rampant introgression and homogenization. The phylogeographic analysis revealed admixture among wild populations; nevertheless, this did not impair pointing to Anatolia as likely having a “refugia-within-refugia” structure. We recommend that the genetic structure of Chukar Partridge and its MUs be taken into account when developing the policy of hunting, production, and release to preserve the genetic integrity of this species.

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“…Although Chukars have been studied extensively (e.g., Nagel, 1945;Alcorn & Richardson, 1951;Barnett, 1952;Galbreath & Moreland, 1953;Christensen, 1954Christensen, , 1970Christensen, , 1996Bohl, 1957;Harper, Harry & Bailey, 1958;Tomlinson, 1960;Moulton, Cropper & Broz, 2015;Moulton et al, 2018;Moulton & Cropper, 2016, little information exists for quantitative comparisons of locations deemed suitable versus not suitable. With this in mind, the goal of our study was to develop quantitative models using machine learning algorithms to assess environmental factors of sites in the Chukar's native range, and to determine/predict most suitable sites for introductions in the 48 contiguous states of the US.…”

Section: Introductionmentioning

confidence: 99%

A quantitative assessment of site-level factors in influencing Chukar (Alectoris chukar) introduction outcomes

Smith

Cropper

Moulton

2021

PeerJ

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Chukar partridges (Alectoris chukar) are popular game birds that have been introduced throughout the world. Propagules of varying magnitudes have been used to try and establish populations into novel locations, though the relationship between propagule size and species establishment remains speculative. Previous qualitative studies argue that site-level factors are of importance when determining where to release Chukar. We utilized machine learning ensembles to evaluate bioclimatic and topographic data from native and naturalized regions to produce predictive species distribution models (SDMs) and evaluate the relationship between establishment and site-level factors for the conterminous United States. Predictions were then compared to a distribution map based on recorded occurrences to determine model prediction performance. SDM predictions scored an average of 88% accuracy and suitability favored states where Chukars were successfully introduced and are present. Our study shows that the use of quantitative models in evaluating environmental variables and that site-level factors are strong indicators of habitat suitability and species establishment.

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Inconsistencies among secondary sources of Chukar Partridge (Alectoris chukar) introductions to the United States

Cited by 6 publications

References 35 publications

Propagule pressure does not consistently predict the outcomes of exotic bird introductions

Propagule pressure does not consistently predict the outcomes of exotic bird introductions

Evidence for Genetic Hybridization between Released and Wild Game Birds: Phylogeography and Genetic Structure of Chukar Partridge, Alectoris chukar, in Turkey

A quantitative assessment of site-level factors in influencing Chukar (Alectoris chukar) introduction outcomes

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