Treesearch

A comprehensive review of biological control of weeds in Hawaii was last published in 1992, covering 74 natural enemy species released from 1902 through 1980. The present review summarizes releases of 21 natural enemies targeting seven invasive weeds from 1981 to 2010. These projects were carried out by Hawaii Department of Agriculture (HDOA), USDA Forest Service (USFS), University of Hawaii (UH), and US Geological Survey Biological Resources Discipline. An appendix summarizing the chronology and outcomes of releases is included (Appendix 1).

The Smith River originates in west central Montana and flows north approximately 100 miles before joining the Missouri River. The central 60 miles of the river flows through a relatively inaccessible, forested, scenic limestone canyon famous for its trout fishing. Because of its popularity, the area was designated Montana's first and only controlled river, with access by a permit system. By 1995, leafy spurge (Euphorbia esula L.) infested roughly 639 acres of the canyon, threatening riparian ecosystems and the natural, cultural, agricultural, and recreational resources along the river...

The gall mite, Aceria genistae (Nal.) Castagnoli s.l., an accidentally introduced natural enemy of Scotch broom (Cytisus scoparius (L.) Link), was first discovered in the Portland OR and Tacoma WA region in 2005. It has since been reported from southern British Columbia to southern Oregon. Observationally, the mite appears to reduce Scotch broom seed production and at high densities can cause extensive stem die-back and plant mortality. In order to utilize the mite as a classical biological control agent, a study of its host range and potential nontarget attack was started in 2006 and...

White ash results from the complete combustion of surface fuels, making it a logically simple retrospective indicator of surface fuel consumption. However, the strength of this relationship has been neither tested nor adequately demonstrated with field measurements. We measured surface fuel loads and cover fractions of white ash and four other surface materials (green vegetation, brown non-photosynthetic vegetation, black char and mineral soil) immediately before and after eight prescribed fires in four disparate fuelbed types: boreal forest floor, mixed conifer woody slash, mixed conifer...

Rush skeletonweed (Chondrilla juncea L.) is a major noxious weed in Idaho and other areas of the Pacific Northwest. A biological control program was implemented during the late 1970s in an attempt to manage infestations of rush skeletonweed and to limit its spread into new areas. Three agents, Cystiphora schmidti (Rübsaamen) (a gall midge), Aceria chondrillae (Canestrini) (a gall mite), and Puccinia chondrillina Bubak & Sydenham (a rust fungus) have been established in Idaho and other areas of the western United States. However these agents have provided only limited control of the weed....

Rush skeletonweed (Chondrilla juncea L.) is an invasive apomictic perennial plant in Australia, South- and North America, accidentally introduced from Eurasia, which shows differential resistance/tolerance to some herbicides and classical biological control agents. Rush skeletonweed biotypes have been locally described using morphology, phenology, isozyme patterns, and resistance to control agents, but studies comparing invasions on different continents and determining exact origins of invasive genotypes do not exist or are lacking in detail. Commonly available molecular tools and bulk...

Aim: Biodiversity and drinking water share a common interest in land conservation. Our objective was to identify where that common interest occurs geographically to inform conservation planning. Location: The study focused on 2112 eight-digit hydrologic units (watersheds) occurring in the conterminous United States. Methods: Data on aquatic-dependent species occurrence, drinking water intakes, protected land status and land cover change were compiled for each watershed. We compared these four datasets after defining ‘hotspots’ based on attribute-specific thresholds that included (1) the...

1. Species richness, the number of species in a defined area, is the most frequently used biodiversity measure. Despite its intuitive appeal and conceptual simplicity, species richness is often difficult to quantify, even in well surveyed areas, because of sampling limitations such as survey effort and species detection probability. Nonparametric estimators have generally performed better than other options, but no particular estimator has consistently performed best across variation in assemblage and survey parameters. 2. In order to evaluate estimator performance, we developed the...

Black-tailed prairie dogs (Cynomys ludovicianus) are considered a keystone species in grassland ecosystems. Through their burrowing activities, they conspicuously alter grassland landscapes and provide foraging, shelter and nesting habitat for a diverse array of grassland species, in addition to serving as prey for the endangered black-footed ferret (Mustela nigripes). Due to a combination of factors, the lands currently occupied by prairie dog colonies are thought to represent less than 10% of their historical range. Black-tailed prairie dogs have difficulty colonizing areas with tall...

Longleaf pine (Pinus palustris) ecosystems are remarkably rich in plant species and represent the dominant upland forest type in several southeastern military installations. Management of these forests on installations is critical both to fulfill the military mission and to conserve this unique natural resource. The researchers will couple a series of field experiments with data mining exercises to help managers meet their objectives for monitoring the impact of various activities on the understory plant community. Results from this project will also aid development of modeling tools to...