The introduction of exotic fishes in streams and water reservoirs has modified autochthonous freshwater fish communities in Puerto Rico. There are approximately 46 fish species in inland waters, and most of them were introduced during the last century. We here summarize relevant information on 46 freshwater fish species reported for the island. Approximately 80% of the species are non-native. An evaluation of the local trade revealed another 128 freshwater fish species are sold locally as pets. This raises serious concerns, as we detected a potential pool of non-native species that are either considered invasive elsewhere, or that, based on their ecology, could become invasive on the island in the near future. We also found that cichlids as a group pose the highest risk to freshwater ecosystems, with 13 species established in the wild, and another 38 potential invaders in the local pet trade. This study may be used as a baseline for the conservation and management purposes of both native and non-native fish species, including the development of strategies for preventing the release of live fish pets into the wild. More specific management for non-native fish, especially those identified here that pose significant threats to Puerto Rico's native fish and their ecosystems, are warranted.
Establishment of new populations is contingent on overcoming abiotic and biotic barriers. While this applies to all species, these hurdles are at the forefront of invasion biology where prediction, prevention, eradication, and control strategies depend on an understanding and exploitation of barriers to establishment and spread. Arundina graminifolia and Dendrobium crumenatum are two invasive orchids spreading throughout Puerto Rico. Current records on their distributions across the island are sparse, and their interactions with the surrounding ecosystem are unknown. Through a direct population survey of all known localities, we identified a new, acquired enemy of both orchids: the orchid-specialist weevil, Stethobaris polita. In this study, we used niche modelling to identify suitable habitats for each orchid on the island and map their current distributions and interactions with S. polita, along with their distributions in the most extreme climate scenario in 2050, in order to contextualize projected patterns of establishment on the island. Our findings show that D. crumenatum flourishes in urban environments which also provide refugia from S. polita. In contrast, there is currently no refugia for A. graminifolia from S. polita attack, as it is more sensitive to the same climatic variables as S.polita. Furthermore, projections into the most extreme climate scenario suggests Puerto Rico will be unsuitable for A. graminifolia and S. polita's survival, and become less suitable for D. crumenatum, by 2050.
In this study, we assessed invasions of Psittaciformes in Puerto Rico. We reviewed the literature, public databases, citizen science records, and performed in situ population surveys across the island to determine the historical and current status and distribution of psittacine species. We used count data from Ebird to determine population trends. For species whose populations were increasing, we modelled their potential distribution using niche modeling techniques. Focusing on the white-winged parakeet (Brotogeris versicolurus), which was considered the most successful psittacine species by the year 2000, we evaluated the population size, calculated growth rates and estimated the breeding proportion in two populations by performing roost counts for four consecutive years. We found a total of 46 Psittaciformes present in Puerto Rico, of which 26% are only present as pets, at least 29 species have been reported in the wild, and of those, there is evidence that at least 12 species are breeding. Our results indicate that most introduced species which have been detected as established still persist, although mostly in localized areas and small populations. Clear evidence of invasiveness was found for B. versicolurus and Myiopsitta monachus, which have greatly expanded their range.Moreover, Psittacara erythrogenys and Eupsittacula canicularis also showed population increase. The niche models predicted suitable areas for the four species, and also indicate the potential for range expansion. Population estimates of the white-winged parakeet during the study period showed a steady increase, and exhibited exponential growth, with geometric mean population growth rates of 1.25 per year. Currently growth rate of the white-winged parakeet does not appear to be limited by any predator, resources or nest availability, and we expect them to continue increasing and expanding their range. We peer-reviewed) is the author/funder. All rights reserved. No reuse allowed without permission.The copyright holder for this preprint (which was not . http://dx.doi.org/10.1101/264937 doi: bioRxiv preprint first posted online Feb. 14, 2018; 3 discuss the factors leading to invasion success, assess the potential impacts, and we discuss possible management strategies and research prospects.
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