Jeffrey Simmons

The United States' use of coal results in many environmental alterations. In the Appalachian coal belt region, one widespread alteration is conversion of forest to reclaimed mineland. The goal of this study was to quantify the changes to ecosystem structure and function associated with a conversion from forest to reclaimed mine grassland by comparing a small watershed containing a 15-year-old reclaimed mine with a forested, reference watershed in western Maryland.

Through the Ecological Research as Education Network (EREN), researchers from the United States and Canada have been developing collaborative research projects aimed at analyzing broad ecological patterns. The Riparian Buffers Affect Stream Temperature (RBAST) project is one of these activities. Temperature variation across ecosystems can be assessed at various spatial and temporal scales. These variations in spatiotemporal patterns can be found in terrestrial and aquatic systems and significantly influence ecosystem ...

ABSTRACT Background/Question/Methods Freshwater turtle populations can be profoundly impacted by urbanization. Adult females may experience high mortality with increased road density near nesting sites, leading to a male-biased population. Juvenile recruitment can be reduced by the high density of predators that often exist in human-dominated landscapes, resulting in an adult-biased population. To determine if the population structure of freshwater turtles follows these patterns at widespread sites with varying degrees of urbanization, over 30 faculty and their students at 26 institutions extending from Massachusetts to Oklahoma conducted a mark-recapture study of turtles inhabiting lentic ecosystems. The research was conceived, organized, and operated through the Ecological Research as Education Network (EREN, www.erenweb.org). EREN facilitates research and collaboration among students and faculty at primarily undergraduate institutions. Between August and early October 2012, each participant placed a minimum of four hoop traps in each of their respective ponds for at least two consecutive days and marked, measured, and released any captured turtles. We sampled a total of 39 ponds. For each pond with a minimum of ten individuals per species, we used chi-square goodness-of-fit tests to analyze whether the adult sex ratio differed from parity and the juvenile:adult ratio differed from 1:5 for each species. Results/Conclusions We caught the painted turtle (Chrysemys picta), pond slider (Trachemys scripta), common snapping turtle (Chelydra serpentina), common musk turtle (Sternotherus odoratus), smooth softshell (Apalone mutica), and common map turtle (Graptemys geographica) across 34 ponds. Turtles were not caught in the other five ponds. Only the painted turtle was caught in sufficient numbers per pond to permit the statistical analysis of age-sex class ratio. It was detected in 29 of the ponds, with 16 ponds yielding captures of at least ten individuals. The adult sex ratio was significantly biased towards adult males in eight ponds and did not differ from parity in the remaining eight ponds. A significant deviation from expectation for the juvenile:adult ratio was detected in six of the 16 ponds. Significantly more juveniles than expected were caught in three ponds and fewer juveniles in the other three ponds. Faculty and students will continue the turtle sampling in fall 2013 and will characterize urbanization by measuring landscape attributes around each sampled pond. As the research continues, we will be able to assess more thoroughly how the population structure of freshwater turtles varies with urbanization across much of North America.

When forested riparian zones are cleared for agriculture or development, major changes can occur in the stream temperature regime and consequently in ecosystem structure and function. Our main objective was to compare the summer temperature regimes of streams with and without forest canopy cover at multiple sites. The secondary objective was to identify the components of the stream heat budget that have the greatest influence on the stream temperature regime. Paired stream reaches (one forested and one non-forested or “open”) were identified at eleven sites distributed across the U.S. and Canada. Stream temperature was monitored at the upstream and downstream ends of 80- to 130-m-long reaches during summer and five variables were calculated to describe the stream temperature regime. Overall, compared to forested reaches, open reaches tended to have significantly higher daily mean (mean difference = 0.33 ± 1.1 °C) and daily maximum (mean difference = 1.0 ± 1.7 °C) temperatures and wider daily ranges (mean difference = 1.1  ± 1.7 °C). Mean and maximum daily net heat fluxes in open reaches tended to be greater (or less negative) than those in forested reaches. However, certain sites showed the opposite trends in some variables because 1) daily mean and maximum temperatures were biased by differences between paired reaches and 2) inputs of cold groundwater exerted a strong influence on temperature. Modeling and regression results suggested that within sites, differences in direct solar radiation were mainly responsible for the observed differences in stream temperature variables at the daily scale.

The forest floor was expected to play a major role in determining the total ecosystem response to watershed liming because of its high concentration of nutrients and its high level of activity. Net N mineralization and net nitrification were estimated in a field survey using the buried-bag approach. In a laboratory incubation experiment, forest floor humus was mixed with 6

Abstract The objective of this study was to evaluate the nitrogen (N) biogeochemistry of an 18–22 year old forested watershed in western Maryland. We hypothesized that this watershed should not exhibit symptoms of N saturation. This watershed was a strong source of nitrate (NO 3−) to the stream in all years, with a mean annual export of 9.5 kg N ha− 1 year− 1 and a range of 4.4–18.4 kg N ha− 1 year− 1. During the 2001 and 2002 water years, wet deposition of inorganic N was 9.0 kg N ha− 1 year− 1 and 6.3 kg N ha− 1 year− 1, ...