Treesearch

Bark beetle outbreaks have killed billions of trees and affected millions of hectares of forest during recent decades. The objective of this study was to quantify responses of surface energy and hydrologic fluxes 2-3 yr following a spruce beetle outbreak using measurements and modeling. The authors used observations at the Rocky Mountains Glacier Lakes Ecosystem Experiments Site (GLEES), where beetles killed 85% of the basal area of spruce from 2005-07 (prebeetle) to 2009/10 (postbeetle). Observations showed increased albedo following tree mortality, more reflected solar radiation, and...

The Neotropical genus, Arachnocoris Scott groups thirteen species of specialized spider web-inhabiting damsel bugs (Nabidae) distributed from Panama to Brazil and the West Indies. We present new information on the web behavior of A. berytoides Uhler from Puerto Rico. Three different life stages were observed on the spider webs, suggesting this species likely depends on that microhabitat for all its life history stages. In addition to the modified tarsi described by Myers, we describe mimetic adaptations that may help it live a life in close association with its predacious host. Species in...

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.