Geology topics

David I. King

Publications and source records attributed to David I. King.

5 recordsLinked to original sources

USGS2021

Pollinator communities vary with vegetation structure and time since management within regenerating timber harvests of the Central Appalachian Mountains

Native pollinator populations across the United States are increasingly threatened by a multitude of ecological stressors. Although the drivers behind pollinator population declines are varied, habitat loss/degradation remains one of the most important threats. Forested landscapes, where the impacts of habitat loss/degradation are minimized, are known to support robust pollinator populations in eastern North America. Within heavily forested landscapes, timber management is already implemented as a means for improving forest health and enhancing wildlife habitat, however, little is known regarding the characteristics within regenerating timber harvests that affect forest pollinator populations. In 2018-19, we monitored insect pollinators in 143 regenerating (≤ 9 growing seasons post-harvest) timber harvest sites across Pennsylvania. During 1,129 survey events, we observed over 9,100 bees and butterflies, 220 blooming plant taxa, and collected over 2,200 pollinator specimens. Bee and butterfly abundance were positively associated with season-wide floral abundance and negatively associated with dense vegetation that inhibits the growth of understory floral resources. Particularly in late summer, few pollinators were observed in stands > 6 years post-harvest, with models predicting five times more bees in 1-year-old harvests than in 9-year-old harvests. Pollinator species diversity was positively associated with floral diversity and percent forb cover, and negatively associated with percent tall (>1m) sapling cover. These results suggest that regenerating timber harvests promote abundant and diverse pollinator communities in the Appalachian Mountains, though pollinator abundance declined quickly as woody stems regenerated. Ultimately, our findings contribute to a growing body of literature suggesting that dynamic forest management producing an even mix of age classes would benefit forest pollinator populations in the Central Appalachian Mountains.

Pennsylvania↗

USGS2018

Effects of early-successional shrubland management on breeding wood thrush populations

In forested landscapes, creation of habitat for early-successional shrubland birds is controversial because of perceived conflicts with the conservation of mature-forest birds. Nonetheless, many mature-forest birds, especially fledglings, readily use early-successional stands during the post-breeding period. This suggests that for mature-forest birds, creating habitat for early-successional birds could involve a tradeoff: reduced abundance and nest survival due to the loss of nesting habitat versus enhanced fledgling survival in early-successional stands. Our research addressed the effects of the creation of early-successional habitat for shrubland birds on wood thrushes ( Hylocichla mustelina ) in western Massachusetts, USA. We compared wood thrush abundance, nest success, fecundity, and post-fledging survival in landscapes with high (∼20%) or low (∼1%) cover of early-successional stands suitable for shrubland birds. We found no differences in nest success, fecundity, and post-fledging survival between the 2 types of landscapes. Abundance of breeders, however, was significantly greater on the sites with high cover of early-successional habitat. We conclude that in forested landscapes, creation of early-successional habitat at levels recommended for the conservation of shrubland birds is compatible with viable wood thrush populations. © 2018 The Wildlife Society.

Massachusetts↗

USGS2016

Research on Golden-winged Warblers: Recent progress and current needs

Considerable advances have been made in knowledge about Golden-winged Warblers ( Vermivora chrysoptera ) in the past decade. Recent employment of molecular analysis, stable-isotope analysis, telemetry-based monitoring of survival and behavior, and spatially explicit modeling techniques have added to, and revised, an already broad base of published knowledge. Here, we synthesize findings primarily from recent peer-reviewed literature on Golden-winged Warblers, from this volume and elsewhere, and we identify some of the substantial remaining research needs. We have organized this synthesis by stages of the Golden-winged Warbler annual cycle. First, we discuss the relatively well-studied breeding-grounds ecology including nesting and post-fledging ecology and hybridization with closely related Blue-winged Warblers ( Vermivora cyanoptera ). Second, we discuss the much-less-studied, non-breeding-grounds ecology, including the first empirical studies of non-breeding-grounds cover-type associations and spatial and social behavioral ecology. Third, we address migratory connectivity and migration ecology, for which little is known and research has only just begun. Last, we close with cautious optimism that current knowledge is adequate to inform initial conservation and management plans for Golden-winged Warblers, and with a sobering acknowledgement of the quantity of research still needed.

Studies in Avian Biology↗

USGS2011

Inference about density and temporary emigration in unmarked populations

Few species are distributed uniformly in space, and populations of mobile organisms are rarely closed with respect to movement, yet many models of density rely upon these assumptions. We present a hierarchical model allowing inference about the density of unmarked populations subject to temporary emigration and imperfect detection. The model can be fit to data collected using a variety of standard survey methods such as repeated point counts in which removal sampling, double‐observer sampling, or distance sampling is used during each count. Simulation studies demonstrated that parameter estimators are unbiased when temporary emigration is either “completely random” or is determined by the size and location of home ranges relative to survey points. We also applied the model to repeated removal sampling data collected on Chestnut‐sided Warblers ( Dendroica pensylvancia ) in the White Mountain National Forest, USA. The density estimate from our model, 1.09 birds/ha, was similar to an estimate of 1.11 birds/ha produced by an intensive spot‐mapping effort. Our model is also applicable when processes other than temporary emigration affect the probability of being available for detection, such as in studies using cue counts. Functions to implement the model have been added to the R package unmarked .

New Hampshire↗

USGS1999

Winter ecology of the endangered golden-cheeked warbler

We studied the ecology of the Golden-cheeked Warbler ( Dendroica chrysoparia ) during three winter seasons, 1995-1998, in Honduras, Guatemala, and Mexico. Individuals of this species occurred almost exclusively as members of mixed-species flocks, occupying sites with greater densities of encino oak and ground cover and fewer pines than random sites. Most foraging observations were recorded in mid-story, encino oak. Commonly-observed foraging maneuvers were gleaning and sally-hovering. Eighty-three percent of foraging maneuvers were directed at the outermost portions of the oak foliage. Flocks in which Golden-cheeked Warblers occurred contained an average of 20.5 individuals and 12.9 species other than Golden-cheeked Warblers. The most frequently co-occurring species were Wilson's Warbler ( Wilsonia pusilla ), Black-throated Green Warbler ( Dendroica virens ), Hermit Warbler ( D. occidentalis ), Townsend's Warbler (D. townsendi), and Blue-headed Vireo ( Vireo solitarius ). The ratio of males to females observed was not substantially different from 1:1, and there was little evidence of sexual differences in habitat use. Golden-cheeked Warblers appeared to be tolerant of moderate levels of logging and grazing, but understory clearing to promote grazing for cattle may pose a significant threat to winter habitat availability.

The Condor↗