Introduced species Research Papers - Academia.edu (original) (raw)

Introduced predators have had, and continue to have, severe impacts on Australian biodiversity. At a recently established conservation reserve, Witchelina, in arid South Australia, we assessed the diet of feral cats (Felis catus) (404... more

Introduced predators have had, and continue to have, severe impacts on Australian biodiversity. At a recently established conservation reserve, Witchelina, in arid South Australia, we assessed the diet of feral cats (Felis catus) (404 samples), red fox (Vulpes vulpes) (51 samples) and dog (Canis familiaris) (11 samples) over a 3-year period. There was marked overlap (98.5%) in dietary composition between cats and foxes. Rabbits (Oryctolagus cuniculus) comprised a major dietary item for all three predators. Invertebrates contributed the largest number of prey items for foxes and cats, but mammals comprised the bulk, by weight, for all three predators. Birds and reptiles had a higher frequency of occurrence in the diet of cats than of foxes or dogs. The size of mammal prey taken was least for cats and greatest for dogs. The diets of cats and foxes showed significant seasonal variation, with reptiles and invertebrates being least common in the diet in winter. The threatened thick-billed grasswren (Amytornis modestus) was found for the first time in the diet of feral cats. Bearded dragons (Pogona vitticeps) occurred in about one-third of cat and fox samples. This study contributes further to the evidence of biodiversity impacts of introduced predators, and the need for their strategic management.

Since the 1980s, morphological and molecular research has resulted in significant advances in understanding the relationships and origins of the recent terrestrial vertebrate fauna in the New Zealand biogeographic region. This research... more

Since the 1980s, morphological and molecular research has resulted in significant advances in understanding the relationships and origins of the recent terrestrial vertebrate fauna in the New Zealand biogeographic region. This research has led to many taxonomic changes, with a significant increase in the number of bird and reptile species recognised. It has also resulted in the recognition of several more Holocene (<10 000 years ago) bird species extinctions. The conclusion that Holocene extinctions were primarily caused by human- hunting and predation by other introduced mammals (particularly rats and cats) has been supported by new data. Despite many local eradications of introduced pests, the number of introduced species has increased, with the establishment of five more foreign birds and (on Norfolk Island) the house gecko ( Hemidactylus frenatus). Many new, significant New Zealand vertebrate fossils have been reported, including more dinosaurs from the Cretaceous, and the fi...

Abstract.—Harvesting of chameleons from the East Usambara Mountains of Tanzania for the exotic pet trade is of concern due to the high rates of habitat loss in this region and the fact that many of the species are endemic or near endemic... more

Abstract.—Harvesting of chameleons from the East Usambara Mountains of Tanzania for the exotic pet trade is of concern due to the high rates of habitat loss in this region and the fact that many of the species are endemic or near endemic to this isolated montane forest. Export of the majority of chameleons found in the East Usambaras is regulated by their listing under CITES Appendix II. To ensure harvesting is sustainable, however, greater knowledge of the ecology of species is needed.

SUMMARYVarious management approaches have been proposed to address the alarming depletion of marine coastal resources. Prominent among them are community-based management and the establishment of marine protected areas (MPAs). The overall... more

SUMMARYVarious management approaches have been proposed to address the alarming depletion of marine coastal resources. Prominent among them are community-based management and the establishment of marine protected areas (MPAs). The overall poor performance of MPAs can be traced to a failure to effectively include local communities in the design and implementation of relevant measures. Recent efforts have incorporated aspects of community-based management into a hybrid form of management, which ideally builds upon existing local management practices. A key challenge lies in the development of appropriate frameworks that allow for the successful participation of local communities in management. A review of studies on MPA design and community-based marine resource management and fieldwork observations provides suggestions on how to address current socioeconomic shortcomings in MPA design and implementation, successfully involving local communities in order to provide a better local basi...

The conservation of endemic fauna in freshwater ecosystems is a topical issue on small oceanic islands. Because these endemics have limited distributions, they are more vulnerable to extinction. This study is the first to clarify the... more

The conservation of endemic fauna in freshwater ecosystems is a topical issue on small oceanic islands. Because these endemics have limited distributions, they are more vulnerable to extinction. This study is the first to clarify the distribution of freshwater macroinvertebrates including endemic and alien species in streams with dams and associated reservoirs on the Ogasawara Islands in the northwestern Pacific Ocean. In 2007, we conducted a field survey in streams and reservoirs of the Yatsuse River system and collected 22 taxonomic groups from 13 stations. Hierarchal cluster analysis and non-metric multi-dimensional scaling (NMDS) were performed for the presence/absence data of the macroinvertebrates, and the results indicated that (1) most of endemic species were present in inlet streams of dam reservoirs, (2) these endemic species were absent in the bottom sediments of the reservoirs because of oxygen depletion and (3) dams may be barriers to the migration of some species of amphidromous crustaceans. Because human modifications, such as dams and associated reservoirs, on a small oceanic island can rapidly result in fragmentation or loss of freshwater habitats of endemic species, the remaining habitat of these species, such as headwater streams, must be protected and preserved to avoid species extinction.

The native distribution of the blue crab Callinectes sapidus in the western Atlantic extends from Nova Scotia to Argentina. Introduced to Europe at the beginning of the 20th century, it is currently recorded almost ubiquitously in the... more

The native distribution of the blue crab Callinectes sapidus in the western Atlantic extends from Nova Scotia to Argentina. Introduced to Europe at the beginning of the 20th century, it is currently recorded almost ubiquitously in the Mediterranean and in the Black Sea. An overview of the occurrence, abundance, and ecological impact of the species in southern European waters is provided; additionally, we present a pragmatic assessment of its management scenarios, explicitly considering the dual nature of C. sapidus as both an invasive species and a fishery resource. We emphasise that the ongoing expansion of C. sapidus in the region may represent a stimulating challenge for the identification and implementation of future strategies in the management of invasive crustaceans. The impact of the invader could be converted into an enhancement of the services delivered by southern European coastal ecosystems, while mitigation costs could be transformed into profits for local populations.

Invasive species introduced via the ballast water of commercial ships cause enormous environmental and economic damage worldwide. Accurate monitoring for these often microscopic and morphologically indistinguishable species is challenging... more

Invasive species introduced via the ballast water of commercial ships cause enormous environmental and economic damage worldwide. Accurate monitoring for these often microscopic and morphologically indistinguishable species is challenging but critical for mitigating damages. We apply eDNA sampling, which involves the filtering and subsequent DNA extraction of microscopic bits of tissue suspended in water, to ballast and harbor water sampled during a commercial ship's 1400 km voyage through the North American Great Lakes. Using a lab-based gel electrophoresis assay and a rapid, field-ready light transmission spectroscopy (LTS) assay, we test for the presence of two invasive species: quagga (Dreissena bugensis) and zebra (D. polymorpha) mussels. Furthermore, we spiked a set of uninfested ballast and harbor samples with zebra mussel tissue to further test each assay's detection capabilities. In unmanipulated samples, zebra mussel was not detected, while quagga mussel was detect...

Our ability to demonstrate statistical patterns of invasion by non-native species will determine the success of future management projects. We investigated the suitability of self-organizing maps (SOM, neural network) for patterning... more

Our ability to demonstrate statistical patterns of invasion by non-native species will determine the success of future management projects. We investigated the suitability of self-organizing maps (SOM, neural network) for patterning habitat invasion by exotic fish species at the regional scale (Southwest France), using a binary dataset of species occurrences. The SOM visualization can be used as an analytical tool to bring out relationships between sample locations and biological variables, but in addition the weight of each species in the output of the SOM can be interpreted as its occurrence probability in various geographic areas. After training the SOM with fish presence/absence data, the k-means algorithm helped to derive three major clusters of sites (headwater, montane, and plain areas). Each cluster was divided into two subsets of sites according to non-native fish, because assemblage compositions delineated different geological areas: Pyrenees Mountains, Massif Central Moun...

Aedes albopictus (Skuse) is an invasive mosquito species found across the southern U.S. with range expansion into many northern states. Intra- and interspecific larval competition have been evaluated for Ae. albopictus with respect to... more

Aedes albopictus (Skuse) is an invasive mosquito species found across the southern U.S. with range expansion into many northern states. Intra- and interspecific larval competition have been evaluated for Ae. albopictus with respect to subsequent adult size, immature and adult survivability, and its capacity to vector pathogens as an adult. However, limited data are available on egg production as related to larval rearing conditions. Because Ae. albopictus is a container-inhabiting mosquito that oviposits in resource-limited habitats, it is found under variable density-dependent conditions. Therefore, we examined the impact of specific rearing conditions on Ae. albopictus clutch size and adult body size; comparing the egg production values and wing lengths from known developmental densities to those from field-collected populations. Field populations varied significantly among collection sites in mean clutch size (23 to 46). These clutch sizes were comparable to the mean clutch sizes...

A population of a non-indigenous armoured catfish Pterygoplichthys aff. pardalis from the Dinh river basin (Khan Hoa province, Vietnam). We provide evidence that this is a fully naturalised self-reproducing population and present data on... more

A population of a non-indigenous armoured catfish Pterygoplichthys aff. pardalis from the Dinh river basin (Khan Hoa province, Vietnam). We provide evidence that this is a fully naturalised self-reproducing population and present data on its reproduction. Batch spawning is noted. Possible threat presented by this population to the native habitat and its inhabitants is discussed along with its possible fate. We also analysed the patterns of the fish colouration, which is the main character used for the identification of the species of this genus. We provide evidence that morphometric traits and patterns of the body colouration do not form discrete clusters. Therefore, systematics of the genus should be revised and several species would likely be invalid.

Food availability is a primary driver of avian population regulation. However, few studies have considered the effects of what is essentially a massive supplementary feeding experiment: the practice of wild bird feeding. Bird feeding has... more

Food availability is a primary driver of avian population regulation. However, few studies have considered the effects of what is essentially a massive supplementary feeding experiment: the practice of wild bird feeding. Bird feeding has been posited as an important factor influencing the structure of bird communities, especially in urban areas, although experimental evidence to support this is almost entirely lacking. We carried out an 18-mo experimental feeding study at 23 residential properties to investigate the effects of bird feeding on local urban avian assemblages. Our feeding regime was based on predominant urban feeding practices in our region. We used monthly bird surveys to compare avian community composition, species richness, and the densities of local species at feeding and nonfeeding properties. Avian community structure diverged at feeding properties and five of the commonest garden bird species were affected by the experimental feeding regime. Introduced birds part...

When nonnative species become established within new communities, competition may play a role in determining the persistence of ecologically similar native species. In western North America, many native cutthroat trout ( Oncorhynchus... more

When nonnative species become established within new communities, competition may play a role in determining the persistence of ecologically similar native species. In western North America, many native cutthroat trout ( Oncorhynchus clarkii ) populations have been replaced by nonnative rainbow trout ( Oncorhynchus mykiss ). Superior competitive ability of rainbow trout and cutthroat–rainbow trout hybrids is often cited for this replacement; however, few studies have tested for mechanisms that might allow introduced rainbow trout to out-compete native trout species. Our previous work found individual-based differences in swimming and foraging ability among cutthroat trout, rainbow trout, and their hybrids. In this study, we tested for the presence and strength of competition between cohorts of cutthroat trout, rainbow trout, and their reciprocal hybrids. We assayed the growth rate of juvenile cutthroat trout in allopatry versus cutthroat trout when sympatric with rainbow trout and e...