The effect of enemy-release and climate conditions on invasive birds: a regional test using the rose-ringed parakeet (Psittacula krameri) as a case study

Shwartz, Assaf, Strubbe, Diederik, Butler, Chris John, Matthysen, Erik and Kark, Salit (2009) The effect of enemy-release and climate conditions on invasive birds: a regional test using the rose-ringed parakeet (Psittacula krameri) as a case study. Diversity and Distributions, 15 2: 310-318. doi:10.1111/j.1472-4642.2008.00538.x


Author Shwartz, Assaf
Strubbe, Diederik
Butler, Chris John
Matthysen, Erik
Kark, Salit
Title The effect of enemy-release and climate conditions on invasive birds: a regional test using the rose-ringed parakeet (Psittacula krameri) as a case study
Journal name Diversity and Distributions   Check publisher's open access policy
ISSN 1366-9516
1472-4642
Publication date 2009-03
Year available 2009
Sub-type Article (original research)
DOI 10.1111/j.1472-4642.2008.00538.x
Open Access Status
Volume 15
Issue 2
Start page 310
End page 318
Total pages 9
Place of publication Oxford, United Kingdom
Publisher Wiley-Blackwell Publishing Ltd.
Collection year 2009
Language eng
Formatted abstract
Aim  Some invasive species succeed particularly well and manage to establish populations across a wide variety of regions and climatic conditions. Understanding how biotic and environmental factors facilitate their invasion success remains a challenge. Here, we assess the role of two major hypotheses explaining invasion success: (1) enemy-release, which argues that invasive species are freed from their native predators and parasites in the new areas; and (2) climate-matching, which argues that the climatic similarity between the exotic and native range determines the success of invasive populations.

Location  India, Israel and the UK.

Methods  We studied the reproductive success of one of the most successful avian invaders, the rose-ringed parakeet (Psittacula krameri), in its native range (India) and in two introduced regions, varying in their climate conditions (Israel and the UK). We combined literature and field data to evaluate the role of predation pressure and climatic conditions in explaining the differences in reproductive success between the three regions.

Results  We found significant differences in reproductive success between regions. In accordance with the enemy-release hypothesis, we discovered that while predation was the main factor responsible for the reduction of fecundity in India, it did not significantly affect the fecundities of parakeet populations in the two introduced regions. In accordance with the climate-matching hypothesis, we found that in the colder temperate UK, egg infertility was high, resulting in lower fecundities. Populations in both the warmer Mediterranean climate of Israel and in the native Indian range had significantly lower egg infertility and higher fecundities than the UK populations.

Main conclusions  Our findings support both the enemy-release and the climate-matching hypotheses. While release from predators facilitates the reproductive success and therefore the invasiveness of parakeets in both the UK and in Israel, colder climate impedes reproduction and therefore the spread of parakeets in the UK.
Keyword Biological invasions
Birds
Infertility
Introduced species
Reproductive success
Nesting Success
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Biological Sciences Publications
 
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