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Beetle Infestation (beetle + infestation)

Distribution by Scientific Domains
Life Sciences50%

Selected Abstracts

Simulation Modeling as a Tool for Understanding the Landscape Ecology of Southern Pine Beetle Infestations in Southern Appalachian Forests

GEOGRAPHY COMPASS (ELECTRONIC), Issue 3 2008
David Martin Cairns
The forests of southeastern North America are influenced by a variety of disturbances including fire and insect outbreaks. In this paper, we discuss the role of disturbances in structuring forest landscapes with particular emphasis placed on the reciprocal interaction between forest structure and outbreaks of the southern pine beetle (Dendroctonus frontalis Zimmermann). We highlight work in which we are currently involved to illustrate the importance and utility of using spatially explicit forest modeling as a tool for understanding forest,insect interactions and its potential role in determining management strategies. [source]

Assessing the effects of post-pine beetle forest litter on snow albedo

HYDROLOGICAL PROCESSES, Issue 6 2010
Rita Winkler
Abstract The effect of forest litter on snow surface albedo has been subject to limited study, mainly in the hardwood-dominated forests of the northeastern United States. Given the recent pine beetle infestation in Western North America and associated increases in litter production, this study examines the effects of forest litter on snow surface albedo in the coniferous forests of south-central British Columbia. Measured changes in canopy transmittance provide an indication of canopy loss or total litterfall over the winter of 2007,2008. Relationships between percent litter cover, an index of albedo, snow depth, and snow ablation during the 2008 melt season are compared between a mature, young, and clearcut coniferous stand. Results indicate a strong feedback effect between canopy loss and subsequent enhanced shortwave transmittance, and litter accumulation on the snow surface from that canopy loss. However, this relationship is confounded by other variables concurrently affecting albedo. While results suggest that a relatively small percent litter cover can have a significant effect on albedo and ablation, further research is underway to extract the litter signal from that of other factors affecting albedo, particularly snow depth. Copyright © 2010 John Wiley & Sons, Ltd. [source]

Pulp handling by vertebrate seed dispersers increases palm seed predation by bruchid beetles in the northern Amazon

JOURNAL OF ECOLOGY, Issue 6 2002
Kirsten M. Silvius
Abstract 1The simultaneous use of fruits and seeds by invertebrate seed predators and vertebrate seed dispersers produces complex ecological interactions that reduce the predictability of seed fate. 2Cocosoid palm seeds in the Neotropics are subject to high mortality by bruchid beetle infestation and such attack is the major cause of mortality for seeds of the palm Attalea maripa at our study site in the northern Brazilian Amazon. 3The exocarp and mesocarp of 1400 fruits were manipulated in different ways to simulate handling by vertebrates. No eggs of the bruchid beetle, Pachymerus cardo, were laid on intact control fruits, while the highest numbers of eggs were received by fruits whose exocarp and mesocarp had been partially removed, as if by primates and rodents (mean of 15.9 and 18.9 eggs fruit,1, respectively, during the peak fruiting season). Fruits with intact mesocarp but no exocarp, and fruits with all mesocarp and exocarp removed, received low numbers of eggs (mean of 4.6 and 6.6 eggs per fruit, respectively, during the peak fruiting season). Thus both exocarp and mesocarp deter oviposition, and removal of these fruit structures increases fruit susceptibility to infestation. 4Oviposition rates declined as the fruiting season progressed, but oviposition preferences remained the same. Seed mortality was high for any fruit on which eggs were laid. 5Large rodents and primates, which have been considered among the most effective seed dispersers for large-seeded Neotropical trees such as palms, actually increased the susceptibility of seeds to bruchid beetle attack. Removal of (intact) seeds by other dispersers may be necessary to ensure seed survival. 6These results indicate that the reliability of seed dispersers cannot be gauged without a complete understanding of variables that affect seed viability. [source]

Detecting spatial hot spots in landscape ecology

ECOGRAPHY, Issue 5 2008
Trisalyn A. Nelson
Hot spots are typically locations of abundant phenomena. In ecology, hot spots are often detected with a spatially global threshold, where a value for a given observation is compared with all values in a data set. When spatial relationships are important, spatially local definitions , those that compare the value for a given observation with locations in the vicinity, or the neighbourhood of the observation , provide a more explicit consideration of space. Here we outline spatial methods for hot spot detection: kernel estimation and local measures of spatial autocorrelation. To demonstrate these approaches, hot spots are detected in landscape level data on the magnitude of mountain pine beetle infestations. Using kernel estimators, we explore how selection of the neighbourhood size (,) and hot spot threshold impact hot spot detection. We found that as , increases, hot spots are larger and fewer; as the hot spot threshold increases, hot spots become larger and more plentiful and hot spots will reflect coarser scale spatial processes. The impact of spatial neighbourhood definitions on the delineation of hot spots identified with local measures of spatial autocorrelation was also investigated. In general, the larger the spatial neighbourhood used for analysis, the larger the area, or greater the number of areas, identified as hot spots. [source]