Benjamin A.,University of California at Davis |
May B.,University of California at Davis |
O'Brien J.,South Coast Region |
Finger A.J.,University of California at Davis
Transactions of the American Fisheries Society | Year: 2016
Urbanization, habitat degradation, fragmentation, and invasive species have led to the severe decline or extirpation of many endemic southern California freshwater fish species, including the Arroyo Chub Gila orcuttii, which has declined precipitously in recent years. Classified by the California Department of Fish and Wildlife as a species of high concern, the Arroyo Chub is native to the Los Angeles, San Gabriel, San Luis Rey, Santa Ana, and Santa Margarita rivers and Malibu and San Juan creeks. To examine Arroyo Chub population structure and genetic diversity within the species' native range, we used 10 microsatellite markers to genotype 259 individuals. We observed moderate to high genetic diversity and population differentiation both between and within drainages; Bayesian clustering supported eight distinct clusters of Arroyo Chub corresponding to eight isolated populations. Of these populations, the Big Tujunga Creek population (Los Angeles River) was the least genetically differentiated (genetic differentiation index FST = 0.048–0.208) and also had the highest genetic diversity (observed heterozygosity Ho = 0.890). Populations in Malibu Creek, Pacoima Canyon (Los Angeles River), and the Santa Margarita River were the most genetically differentiated (FST = 0.163–0.400), had the lowest genetic diversity (Ho = 0.556–0.680), and showed evidence of past bottlenecks. Arroyo Chub at these localities are at risk for continued loss of genetic diversity due to drift and small population sizes; therefore, we suggest that in the event of extirpation, translocations from the most closely related source populations should be considered. However, we recommend that management efforts focus on improving habitat quality and habitat area for Arroyo Chub in order to maximize population genetic diversity and adaptive potential over time. Received July 10, 2015; accepted November 16, 2015 © 2016, © American Fisheries Society 2016.
A review of the catchment approach techniques used to manage a phytophthora cinnamomi infestation of native plant communities of the fitzgerald river national park on the south coast of Western Australia
Dunne C.P.,17 Dick Perry Drive |
Crane C.E.,17 Dick Perry Drive |
Lee M.,South Coast Region |
Massenbauer T.,South Coast Region |
And 6 more authors.
New Zealand Journal of Forestry Science | Year: 2011
The Fitzgerald River National Park (FRNP) is an International Biosphere Reserve on the south coast of Western Australia. The National Park is recognised for its high biodiversity with over 2000 plant species (including many endemics), threatened ecological communities and rare fauna. In contrast with many other areas of high biodiversity value in the region, the FRNP remains largely free of the introduced plant pathogen, Phytophthora cinnamomi Rands, with less than 0.1% of the Park currently infested. Phytophthora cinnamomi was introduced to the FRNP in 1971 with the construction of the unauthorised Bell Track. Currently, the pathogen is located within an internally draining catchment giving some opportunity for limiting its spread into the rest of the FRNP. In recognition of this, a multi-disciplinary integrated management plan has been implemented to contain P. cinnamomi within the current infested catchment. The management plan aimed to accurately identify the area infested with the pathogen, contain it within the current catchment boundaries and reduce the impact on the native plant communities within the infested area. Containment of P. cinnamomi within the current catchment protects tens of thousands of hectares of healthy heathland within the Park from the impact of the pathogen. This review summarises a range of management techniques that have been used to contain the infestation. These techniques include: delimitation with remote sensing technologies; construction of hydrological engineering controls for management of overland flow; installation of vehicle-wash facilities; installation of an animal exclusion perimeter fence and animal control within the fenced area; implementation of strict hygiene and access protocols; installation of root impervious membranes; the application of fungicides and fumigants; rehabilitation of the infested area; and controlled wildfire management. © 2011 New Zealand Forest Research Institute Limited, trading as Scion.
O'Brien J.W.,South Coast Region |
Hansen H.K.,South Coast Region |
Stephens M.E.,South Coast Region
California Fish and Game | Year: 2011
We studied the distribution and relative abundance of fishes in the Upper San Gabriel River (USGR), Los Angeles County, California, during the spring and summer of 2007 and 2008. The USGR is one of the few basins in southern California that still supports an abundant endemic fish community, and is widely recognized as an important area for the conservation of native fishes. Three species of native fishes currently occupy the basin; the most abundant and widely distributed is Santa Ana speckled dace (Rhinichthys osculus ssp.), followed by Santa Ana sucker (Catostomus santaanae), and arroyo chub (Gila orcutti). Santa Ana sucker were most abundant and widely distributed in the East Fork of the San Gabriel River. Santa Ana speckled dace were most abundant in the North Fork and most widely distributed in the West Fork, and arroyo chub were most abundant and widely distributed in the West Fork. Rainbow trout (Oncorhynchus mykiss) also inhabit the USGR and were the most abundant and widely distributed fish in the basin. Like speckled dace, rainbow trout were most abundant in the North Fork and most widely distributed in the West Fork. The overall distribution of the native fish assemblage is comparable, albeit slightly lower, than basinwide distribution surveys conducted in 1975 and 1991. The USGR lies within one of the most frequently visited national forests in the United States, is essential to the conservation of the imperiled Santa Ana sucker and Santa Ana speckled dace, and should be managed both for endemic taxa and recreational values.
Barrett S.,South Coast Region |
Austral Ecology | Year: 2015
Throughout the world, mountains provide unique environments with attendant endemic species. In the otherwise subdued landscapes of the floristically diverse Southwest Western Australian Floristic Region, the Stirling Range provides the region's only distinctly montane environments. On the highest peaks of the Range the characteristic heathland (Kwongan) of the region becomes a dense shrub thicket with many endemic species and is known as the Eastern Stirling Range Montane Heath and Thicket. We assessed the conservation status of the Montane Heath and Thicket using the IUCN Red list criteria for ecosystems. We found the ecosystem to be Critically Endangered based on its naturally limited geographic extent and area of occupancy in combination with the impacts of the plant pathogen Phytophthora cinnamomi. Historical sources and long-term monitoring were critical to our assessment of this ecosystem highlighting their importance in detecting and understanding likely causes of change. The ecosystem is predicted to decline further in the absence of intensive management due to current threatening processes as well as the potential future impacts of climate change. The Montane Heath and Thicket, while substantially modified still retains areas with highly significant conservation values and these pose many challenges for management. Continued management of P.cinnamomi through phosphite application and management of fire return intervals will be critical to conserve the remaining areas of the thicket where sensitive plant species occur together with an ex situ conservation program including ongoing seed collection and translocation for the most threatened species. © 2014 Ecological Society of Australia.
Cochrane J.A.,Flora Conservation and Herbarium Program |
Barrett S.,South Coast Region |
Monks L.,Flora Conservation and Herbarium Program |
Dillon R.,Flora Conservation and Herbarium Program
Kew Bulletin | Year: 2010
Summary: South West Western Australia has a rich endemic flora of global significance. The threats facing this floral diversity are increasing in type, severity and scale, demonstrated by the rising numbers of species threatened with extinction. In particular, the root-rot pathogen Phytophthora cinnamomi is causing widespread destruction, threatening the survival of many of the region's unique plants. In situ conservation of wild plants is considered the most essential component of a flora conservation program, but the ability to conserve some species adequately is often unachievable in the short term and urgent management intervention is required to prevent extinction. We present data on the status and management of wild populations of four threatened species from the region, including an ex situ program, and describe our efforts to bridge the gap between these two components. Such inter situ conservation recovery work enables monitoring of biological attributes, research into reproductive biology and collection of genetic material for further ex situ conservation, and provides the source of material for future restoration of wild populations. © 2011 The Board of Trustees of the Royal Botanic Gardens, Kew.