Treesearch

Ecologists can be overwhelmed by the number of metrics available to quantify landscape structure. Clarification of interrelationships and redundancy is needed to guide metric selection and interpretation for the purpose of landscape monitoring. In this study we identified independent components of class- and landscape-level structure in multiple landscapes in each of three large and geographically disjunct study areas. We used FRAGSTATS and principal components analysis (PCA) to identify independent components of landscape structure, and cluster analysis to group the components. We then...

The control of tansy ragwort on the coast of western North America is a major success story for weed biological control. However, tansy ragwort is still expanding into the colder interior regions of the Pacific Northwest of the United States where previous efforts to establish the same complex of agents have failed. We have successfully established one of the agents, the cinnabar moth, Tyria jacobaeae L., on a major new tansy ragwort infestation in the mountains of northwestern Montana. The cinnabar moth is still expanding its range, but in the areas where first released, it has given...

Surveys were conducted between 1982 and 1995 on banana poka, Passiflora mollissima Bailey (also known as P. tarminiana, subgenus Tacsonia) and related species in the Andes Mountains of South America. The objective was to identify potential biocontrol agents for control of banana poka in Hawaii, USA. Host-related insect diversity was greatest in Colombia, Ecuador, Peru and Venezuela, and poorest in Bolivia and Chile. Insect species observed represented eight orders, 35 families and approximately 67 species. Fifteen species were evaluated as potential biocontrol agents, of which five...

The genus Kochia and Bassia with which it has been combined, of Chenopodiaceae tribe Camphorosmeae, were at one time considered to include plants native to Eurasia, Australia, and North America, and included species of both C3 and C4 photosynthetic types. This aggregate has been reduced in size by removal of a large group of C3 Australian genera and species. Because of their intercontinental disjunction, the presence of root sprouting, and the results of recent phylogenetic studies, it appears that the two North American species Kochia americana and K. californica, of C3 photosynthetic...

The toadflax stem mining weevil, Mecinus janthinus Germar, was first released in the United States in Montana, in 1996. This agent has now become established to varying degrees after subsequent releases made at sites throughout the state. Multiple releases of M. janthinus have presented researchers with a unique opportunity to evaluate the efficacy of this agent in diverse habitats and under a variety of environmental conditions. The results presented in this paper summarize findings from long-term field data, illustrating not only the impact of M. janthinus on the target weed, Dalmatian...

Water has shaped the American West. Nowhere is this more evident than along the Front Range of Colorado. At the west end of the famous Great Plains rainfall gradient, the Front Range extends most of the length of Colorado and is one of the fastest growing metropolitan regions in the nation. Annual precipitation along the Front Range averages about 16 inches, and regional development has been possible only through the manipulation of Rocky Mountain rivers. Since the late 1830s, human changes to water flows have gone from the destruction of the beaver - the earliest water impounders and...

Root disease pathogens, such as Armillaria solidipes Peck (recently recognized older name for A. ostoyae), will likely have increasing impacts to forest ecosystems as trees undergo stress due to climate change. Before we can predict future impacts of root disease pathogens, we must first develop an ability to predict current distributions of the pathogens (and their hosts). Reliable predictions depend on knowing precise locations of accurately identified pathogens and their host species. Thus, the goal of this study is to obtain baseline information on Armillaria spp. distributions in the...

Negatively orthogeotropic (NOGT) tiller and diageotropic (DGT) rhizome meristems develop from the same type of lateral axillary meristems and phytomer structure. Although subterranean NOGT and DGT buds appear similar, they display different responses to gravity and perhaps other cues governing branch angle and overall growth habit (GH). Leymus wildryes show remarkable variation in GH and include some of the largest native grasses in western North America. Previous studies detected GH QTLs on homoeologous regions of LG3a and LG3b controlling differences between caespitose Leymus cinereus...

Mindful organizing has been proposed as an adaptive form for unpredictable, unknowable environments. Mindfulness induces a rich awareness of details and facilitates the discovery and correction of ill-structured contingencies so that adaptations can be made as action unfolds. Although these ideas are appealing, empirical studies examining mindfulness and its effects are limited. This study aims at remedying this situation. We use qualitative and quantitative data gathered from wildland firefighters to empirically examine the extent to which mindful organizing contributes to adaptive...

Leymus cinereus and L. triticoides are large caespitose and rhizomatous perennial grasses, respectively. Previous studies detected quantitative trait loci (QTL) controlling rhizome spreading near the viviparous1 (vp1) gene markers on linkage groups LG3a and LG3b in two families, TTC1 and TTC2, derived from Leymus triticoides x Leymus cinereus hybrids. The wheat tiller inhibition gene (tin3) is located on Triticum monococcum chromosome 3 AmL near vp1. Triticeae group 3 is reportedly collinear with rice chromosome 1, which also contains the maize barren stalk1 and rice lax branching orthogene...