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Baldwin, PA, United States

Hagedorn B.,California State University, Long Beach | Kerfoot H.B.,Civil and Environmental Consultants Inc. | Verwiel M.,Waste Management Inc. | Matlock B.,Waste Management Inc.
Waste Management | Year: 2015

In this study, a multi-tracer approach was applied to a complex, methane-impacted site in Southern California to (1) distinguish between natural gas and landfill gas (LFG)-derived methane impacts at site perimeter gas probes, (2) estimate the relative age of the LFG at these probes, and (3) document natural attenuation trends during a 3-year monitoring period. Relationships between methane and ethane values suggest that at the majority of probes, methane is from LFG and not from natural gas and that the relative contribution of LFG methane at these probes has increased over the monitoring period. To evaluate whether LFG is attenuating in the subsurface, the relative age of LFG was estimated by comparing readily degraded VOCs that are major constituents in LFG (toluene in this case) with those resistant to degradation (Freons). Time-series data trends are consistent with several probes being impacted by fresh LFG from recent releases that occurred after the update of the local LFG collection and control system (LFGCCS). Data further indicate some probes to be only affected by legacy LFG from a past release that occurred prior to the LFGCCS update and that, because of a lack of oxygen in the subsurface, had not been fully degraded. The outlined attenuation evaluation methodology is potentially applicable to other sites or even groundwater contaminants; however, the assessment is limited by the degree of homogeneity of the LFG source composition and non-LFG-derived toluene inputs to the analyzed samples. © 2015.

Wheatall L.,Indiana University of Pennsylvania | Nuttle T.,Indiana University of Pennsylvania | Nuttle T.,Civil and Environmental Consultants Inc. | Yerger E.,Indiana University of Pennsylvania
Conservation Biology | Year: 2013

Externally feeding phytophagous insect larvae (i.e., caterpillars, here, larval Lepidoptera and sawflies, Hymenoptera: Symphyta) are important canopy herbivores and prey resources in temperate deciduous forests. However, composition of forest trees has changed dramatically in the eastern United States since 1900. In particular, browsing by high densities of white-tailed deer (Odocoileus virginianus) has resulted in forests dominated by browse-tolerant species, such as black cherry (Prunus serotina), and greatly reduced relative abundance of other tree species, notably pin cherry (Prunus pensylvanica) and birches (Betula spp.). To quantify effects of these changes on caterpillars, we sampled caterpillars from 960 branch tips of the 8 tree species that comprise 95% of trees in Allegheny hardwood forests: red maple (Acer rubrum), striped maple (Acer pensylvanicum), sugar maple (Acer saccharum), sweet birch (Betula lenta), yellow birch (Betula allegheniensis), American beech (Fagus grandifolia), black cherry, and pin cherry. We collected 547 caterpillar specimens that belonged to 66 Lepidoptera and 10 Hymenoptera species. Caterpillar density, species richness, and community composition differed significantly among tree species sampled. Pin cherry, nearly eliminated at high deer density, had the highest density and diversity of caterpillars. Pin cherry shared a common caterpillar community with black cherry, which was distinct from those of other tree hosts. As high deer density continues to replace diverse forests of cherries, maples, birches, and beech with monodominant stands of black cherry, up to 66% of caterpillar species may be eliminated. Hence, deer-induced changes in forest vegetation are likely to ricochet back up forest food webs and therefore negatively affect species that depend on caterpillars and moths for food and pollination. © 2013 Society for Conservation Biology.

Nuttle T.,Indiana University of Pennsylvania | Nuttle T.,Civil and Environmental Consultants Inc. | Royo A.A.,U.S. Department of Agriculture | Adams M.B.,U.S. Department of Agriculture | Carson W.P.,University of Pittsburgh
Ecological Monographs | Year: 2013

Eastern deciduous forests are changing in species composition and diversity outside of classical successional trajectories. Three disturbance mechanisms appear central to this phenomenon: fire frequency is reduced, canopy gaps are smaller, and browsers are more abundant. Which factor is most responsible is a matter of great debate and remains unclear, at least partly because few studies have simultaneously investigated more than one process. We conducted a large-scale experiment in mesophytic forests of West Virginia, USA, to test three key hypotheses: (1) the fire hypothesis (fire suppression limits diversity to few shade-tolerant, fire-intolerant species that replace and suppress many fire-tolerant species); (2) the gap hypothesis (small gaps typical of today's forests promote dominance of a few shade-tolerant species); and (3) the browsing hypothesis (overbrowsing by deer limits diversity to a few unpalatable species). We tested these hypotheses using a factorial experiment that manipulated surface fire, large canopy gap formation (gap size; 255 m 2), and browsing by deer, and we followed the fates of >28 000 seedlings and saplings for five years. Understory tree communities in control plots were dominated (up to 90%) by Fagus grandifolia, averaging little more than two species, whereas overstories were diverse, with 10-15 species. Fire, large canopy gaps, and browsing all dramatically affected understory composition. However, our findings challenge views that fire and large canopy gaps can maintain or promote diversity, because browsers reduced the benefits of gaps and created depauperate understories following fire. Consequently, two major disturbances that once promoted tree diversity no longer do so because of browsing. Our findings appear to reconcile equivocal views on the role of fire and gaps. If browsers are abundant, these two disturbances either depress diversity or are less effective. Alternatively, with browsers absent, these disturbances promote diversity (three- to fivefold). Our results apply to large portions of eastern North America where deer are overabundant, and we provide compelling experimental evidence that historical disturbance regimes in combination with low browsing regimes typical of pre-European settlement forests could maintain high tree species diversity. However, restoring disturbances without controlling browsing may be counterproductive. © 2013 by the Ecological Society of America.

Hartman K.J.,West Virginia University | Logan M.N.,Civil and Environmental Consultants Inc.
Northeastern Naturalist | Year: 2010

Salvelinus fontinalis (Brook Trout) are simultaneously the subject of eradication efforts in the western US and restoration efforts in the East. Thus, knowledge of their habitat requirements are important to management as well as ecological understanding of the species. Previous studies have evaluated habitat use and movement of established, resident Brook Trout, but none had looked at how transplanted Brook Trout respond in novel environments, nor has habitat selection been evaluated under different flow regimes that may detect differential use of primary habitat. We implanted wild Brook Trout with radio tags and tracked their movement for approximately 30 days during late spring 2002 and early spring 2003 in a central Appalachian stream. The hypotheses tested were: (1) there is no difference between habitat used by novel Brook Trout and available habitat, and (2) stream discharge levels have no effect on Brook Trout habitat selection. The daily tracking of fish in this study also permitted us to quantify fish movement. Brook Trout showed a preference for pool habitatsusing them in greater proportion than availabilityas well as a preference for large woody debris as cover. Overall, we found stream discharge did not affect habitat use. However, under low discharge levels, a negative relationship between discharge and pool use was detected, suggesting restriction to pool habitats under low flows. Home ranges of Brook Trout derived from radio telemetry averaged 450 msimilar to values obtained in other Appalachian studies employing mark-and-recapture methods. A comparison of our results with those of other studies suggests that Brook Trout released into novel environments move and select habitat similar to fish that have local knowledge of the environment.

McAllister B.D.,Civil and Environmental Consultants Inc.
MSW Management | Year: 2010

All of these concerns and recommendations utilize and provide a basic common-sense approach to driver safety in a landfill environment. The recommendations are based on 25 years of practical hands-on experience working in landfills and dealing with the consequences of each of these potential safety concerns. A landfill is a very dangerous environment, but, with some common sense, a constant awareness of your surroundings, and following a few basic safety practices, it can be a pleasant, safe experience for the driver, customer and employees of the facility.

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