Treesearch

The Chinese herb Fritillaria walujewii Regel is an important officinal species that is vulnerable because of over-harvesting. Here, we examined the geographic pattern of genetic variation across the species entire range, to study its evolution process and give implication needed for the conservation. Nine haplotypes were detected on the basis of three chloroplast spacers. The most common haplotype was central in the haplotype network and was distributed widely from the Yili Valley to the eastern Tianshan Mountains. Genetic variation primarily occurred among populations and SAMOVA groups...

Caragana, a leguminous genus mainly restricted to temperate Central and East Asia, occurs in arid, semiarid, and humid belts, and has forest, grassland, and desert ecotypes. Based on the previous molecular phylogenetic tree and dating, biogeographical analyses of extant species area and ecotype were conducted by means of four ancestral optimization approaches: S-DIVA, Lagrange, Mesquite, and BBM. The results indicate the ancestral attributes of Caragana as an arid origin from the Junggar Basin and arid belt of climate and vegetation in the middle Miocene. The ancestral ecotype was most...

Many cases of intercontinental disjunct distributions of seed plants have been investigated, however few have concerned the continents of Eurasia (mainly Central Asia), Africa, and Australia, especially the xerophytic lineages are lacking. Nitraria (Nitrariaceae) is just one of these xerophytic lineages. Previous Nitraria studies have hypothesized either Africa as the ancient center, with dispersals to Australia and Eurasia, or alternatively Central Asia, due to a concentration of endemism and diversity there. Our findings show eastern Central Asia, i.e. the eastern Tethys, to be the...

Thermopsideae has 45 species and exhibits a series of interesting biogeographical distribution patterns, such as Madrean-Tethyan disjunction and EastAsia-North America disjunction,with a center of endemism in the Qinghai-Xizang Plateau (QTP) and Central Asia. Phylogenetic analysis in this paper employed maximum likelihood using ITS, rps16, psbA-trnH, and trnL-F sequence data; biogeographical approaches included BEASTmolecular dating and Bayesian dispersal and vicariance analysis (S-DIVA).The results indicate that the core genistoides most likely originated in Africa during the Eocene to...

A small town relies on a forested watershed for its water supply. The forest is at risk for a wildfire. To reduce this risk, some of the watershed will be thinned followed by a prescribed burn. This paper reports on a study to evaluate the impact of such watershed disturbances on water yield. To target management activities, a fire spread model was applied to the landscape that contains the watershed. The output from the fire spread model was used to develop input files for a watershed hydrology and erosion model. The resulting erosion map was used to identify hillslope polygons that would...

The Water Erosion Prediction Project (WEPP) model, originally developed for hillslope and small watershed applications, simulates complex interactive processes influencing erosion. Recent incorporations to the model have improved the subsurface hydrology components for forest applications. Incorporation of channel routing has made the WEPP model well suited for large watersheds. However, the model is still limited in modeling forested watersheds where groundwater baseflow is substantial, and where snow accumulation and melt dominate winter hydrology.

Land managers are increasingly interested in improving resilience to disturbances, such as wildfire, and resistance to invasive species, such as cheatgrass and medusahead. This factsheet is designed to assist land managers in using resilience and resistance concepts to assess risks, prioritize management activities, and select appropriate treatments.

Bareroot or container seedlings can be used to quickly re-establish big sagebrush and other native shrubs in situations where direct seeding is not feasible or unlikely to succeed. Guidelines are provided for developing a planting plan and timeline, arranging for seedling production, and installing and managing outplantings.

A theoretically based analytic model of plant growth in single species conifer communities based on the species fully occupying a site and fully using the site resources is introduced. Model derivations result in a single equation simultaneously describes changes over both, different site conditions (or resources available), and over time for each variable for each species. Leaf area or biomass, or a related plant community measurement, such as site class, can be used as an indicator of available site resources. Relationships over time (years) are determined by the interaction between a...

Fritillaria pallidiflora is an endangered officinal herb distributed in the Tianshan Mountains of northwestern China. We examined its phylogeography to study evolutionary processes and suggest implications for conservation. Six haplotypes were detected based on three chloroplast non-coding spacers (psbA-trnH, rps16, and trnS-trnG); genetic variation mainly occurred among populations and SAMOVA groups. This species is distributed in different deep valleys, and we speculate that these fragmented habitats cause gene flow barriers among populations and groups. We also speculate that during...