Treesearch

The black turpentine beetle, Dendroctonus terebrans Olivier is the largest pine-infesting bark beetle native to the southern and eastern United States. It generally reproduces in fresh stumps and bases of trees weakened or killed by other biotic or abiotic agents, although it can also infest and sometimes kills apparently healthy trees. Its numbers can build when large amounts of host material become available (typically through a disturbance), and black turpentine beetle-caused mortality at a local scale can become considerable. Here, we provide a complete review of the literature on this...

Landscapes and ecosystems in the Mediterranean basin (MB) have been profoundly modified after a long history of land use and deforestation, which has caused extensive land degradation. In the last third of the 20th century, extensive land abandonment occurred in European Mediterranean countries, which dramatically increased fuel load and continuity in landscape and, consequently, large wildfires. As a response to land degradation, the forest services of MB countries already promoted large afforestations in the late 19th century. After the breakout of large wildfires and the new social...

A wide range of disturbances including recreation, utility corridors, too frequent fire and invasive plants have led to the type conversion of native chaparral habitats to non-native grasslands on the Angeles National Forest. These often compounding disturbances have led to the recent planning, implementation and monitoring of a wide variety of restoration techniques across the forest. Restoration techniques have included imprinting, hydroseeding, container planting and aggressive weed control with a variety of results. Factors influencing these results are adequacy of planning, timelines,...

One of the first tasks in restoration planning is determining the appropriate native plant species and associated quantities. Species with the greatest prevalence at the restoration site, collectability, heat, sunlight and disturbance tolerance, germination and reproduction rate, large growth habit, soil retention qualities, nitrogen fixation, wildlife habitat value, and weed competitiveness were the main traits considered and desired. After this analysis is completed, a listing of on average twenty different species is generated, along with seeding or planting rates per acre for each...

Aim: The stratification of organisms along elevational gradients is widely reported, with montane communities characterized by species occurring in relatively small and isolated populations; these species are of considerable interest to ecologists and conservationists. This stratification is generally attributed to climatic zonation. Evidence that species are shifting upward in elevation has fuelled speculation that species are tracking their climatic niches in response to climate change. Uncertainty regarding the degree to which climate directly influences species abundance versus the...

Effective monitoring of native bee populations requires accurate estimates of population size and relative abundance among habitats. Current bee survey methods, such as netting or pan trapping, may be adequate for a variety of study objectives but are limited by a failure to account for imperfect detection. Biases due to imperfect detection could result in inaccurate abundance estimates or erroneous insights about the response of bees to different environments. To gauge the potential biases of currently employed survey methods, we compared abundance estimates of bumblebees (Bombus spp.)...

On the subtropical and tropical wintering grounds of migratory birds, variation in moisture levels and habitat can influence the availability of food resources and subsequently impact overwintering birds. Using stable carbon isotopes in blood samples as a measure of moisture, we assessed the interactive effects of rainfall, vegetation, and moisture on the demographics and condition of Prairie Warblers (Setophaga discolor) wintering in The Bahamas. Carbon isotopes in Prairie Warbler blood were more depleted in taller, wetter habitats; we additionally detected novel temporal effects of...

For bird species in which plumage characteristics are associated with social dominance, the analysis of status badges may reveal habitat preferences. We analyzed the extent of male Chestnut-sided Warbler (Setophaga pensylvanica) chestnut-colored plumage in relation to age and body size to determine whether badge size was a potential indicator of resource-holding potential. We then modeled badge size in relation to habitat variables including habitat patch size, patch shape, and microhabitat characteristics in 101 different silvicultural openings in western Massachusetts during 2014 and...

Securing desirable regeneration is essential to sustainable forest management, yet failures are common. Detailed seedling measurements from a forest inventory across 24 northern US states were examined for plausible regeneration outcomes following overstory removal. The examination included two fundamental regeneration objectives: 1) stand replacement- securing future forest and 2) species maintenance- securing upper canopy species. Almost half the plots lacked adequate seedlings to regenerate a stand after canopy removal and over half risked compositional shifts. Based on those advance...

Increased fire frequency, livestock grazing, and other disturbances have converted many chaparral stands in southern California to non-native annual grassland. Competition from annual grasses interferes with the establishment of chaparral shrubs, presenting a challenge to restoring chaparral in type-converted areas. In this study we examined the feasibility of restoring chaparral by exploring several methods of restoration on type-converted slopes in San Timoteo Canyon, Riverside County, California. We assessed the effectiveness of a broad-spectrum herbicide (glyphosate) and a grass-specifi...