Limiting Factor For Establishment Research Articles

Assessment of the probability of introduction of Thaumatotibia leucotreta into the European Union with import of cut roses.

Following a request from the European Commission, the EFSA Panel on Plant Health performed a quantitative pest risk assessment to assess whether the import of cut roses provides a pathway for the introduction of Thaumatotibia leucotreta (Lepidoptera: Tortricidae) into the EU. The assessment was limited to the entry and establishment steps. A pathway model was used to assess how many T.leucotreta individuals would survive and emerge as adults from commercial or household wastes in an EU NUTS2 region climatically suitable in a specific season. This pathway model for entry consisted of three components: a cut roses distribution model, a T. leucotreta developmental model and a waste model. Four scenarios of timing from initial disposal of the cut roses until waste treatment (3, 7, 14 and 28 days) were considered. The estimated median number of adults escaping per year from imported cut roses in all the climatically suitable NUTS2 regions of the EU varied from 49,867 (90% uncertainty between 5,298 and 234,393) up to 143,689 (90% uncertainty between 21,126 and 401,458) for the 3- and 28-day scenarios. Assuming that, on average, a successful mating will happen for every 435 escaping moths, the estimated median number of T. leucotreta mated females per year from imported cut roses in all the climatically suitable NUTS2 regions of the EU would vary from 115 (90% uncertainty between 12 and 538) up to 330 (90% uncertainty between 49 and 923) for the 3- and 28-day scenarios. Due to the extreme polyphagia of T. leucotreta, host availability will not be a limiting factor for establishment. Climatic suitability assessment, using a physiologically based demographic modelling approach, identified the coastline extending from the northwest of the Iberian Peninsula through the Mediterranean as area suitable for establishment of T. leucotreta. This assessment indicates that cut roses provide a pathway for the introduction of T. leucotreta into the EU.

Importation of psychrotolerant fungi to Antarctica associated with wooden cargo packaging

AbstractThe harsh climatic conditions and low levels of human activity in Antarctica, relative to other regions, means few non-native species have established. However, the risk of introductions is becoming greater as human activity increases. Non-native microorganisms can be imported to Antarctica in association with fresh food, cargo and personal clothing, but the likelihood of their establishment is not well understood. In January 2015, a wooden packing crate, heavily contaminated with fungi, was imported by aircraft from Punta Arenas, Chile, to Rothera Research Station, Antarctica.Mucor racemosusBull. and two strains ofTrichoderma viridescens(A.S. Horne & H.S. Will.) Jaklitsch & Samuels were isolated from the wood. Measurements of hyphal extension rates indicated that all three strains were psychrotolerant and capable of growth at 4°C, withM. racemosusgrowing at 0°C. The imported fungi could grow at rates equivalent to, or faster than, species isolated from Antarctic soils, suggesting that low temperature may not be a limiting factor for establishment. It is recommended that wood heat-treatment standards, equivalent to those described in the International Standards for Phytosanitary Measures No. 15, are employed by national operators importing cargo into Antarctica, and that treated wood is adequately stored to prevent fungal contamination prior to transportation.

Reproductive timing as a constraint on invasion success in the Ring-necked parakeet (Psittacula krameri)

Climate similarity favors biological invasion, but a match between seasonality in the novel range and the timing of life cycle events of the invader also influences the outcome of species introduction. Yet, phenology effects on invasion success have generally been neglected. Here we study whether a phenological mismatch limits the non-native range of a globally successful invader, the Ring-necked parakeet, in Europe. Given the latitudes at which parakeets have established across Europe, they breed earlier than expected based on breeding dates from the native Asian range. Moreover, comparing the breeding dates of European populations to those of parakeets in the native Asian range, to five native breeding bird species in Europe and to the start of the growing season of four native European trees shows that the discrepancy between expected and actual breeding phenology is greater in northern Europe. In northern European populations, this temporal mismatch appears to have negative effects on hatching success, and on population growth rates in years that are colder than average in the first six months. Phenological mismatch also can explain why parakeets from African populations (that are more likely to breed in autumn) have been poor invaders compared to parakeets from Asia. These lines of evidence support the hypothesis that the reproductive phenology of the Ring-necked parakeet can be a limiting factor for establishment and range expansion in colder climates. Our results provide growing support for the hypothesis that the match between climate seasonality and timing of reproduction (or other important life cycle events) can affect the establishment success, invasive potential and distribution range of introduced non-native species, beyond the mere effect of climate similarity.