Bryans Road, MD, United States
Bryans Road, MD, United States

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Swarth C.W.,Jug Bay Wetlands Sanctuary | Delgado P.,Chesapeake Bay National Estuarine Research Reserve in Maryland | Whigham D.F.,Smithsonian Environmental Research Center
Estuaries and Coasts | Year: 2013

Tidal freshwater wetlands are complex, species-rich ecosystems located at the interface between tidal estuaries and nontidal rivers. This study conducted on the Patuxent River estuary in Maryland was designed to assess vegetation dynamics over several decades to determine if there were directional changes in the dominant communities. Aerial photographs (1970, 1989, and 2007) documented broad-scale spatial changes in major plant communities. The coverage of areas dominated by Nuphar lutea and Phragmites australis expanded; mixed vegetation and scrub-shrub habitats were essentially unchanged; and Typha and Zizania aquatica communities fluctuated in coverage. Data collected between 1988 and 2010 from permanent plots and transects were used to examine fine-scale changes. Shifts in the importance of some species through time were observed, but there were no directional changes in community species composition. The lack of directional change as measured at a fine scale is characteristic of tidal freshwater wetlands in which variations in the abundance of individual species, especially annuals, are responsible for most short-term change in species composition. Changes in the composition of plant communities are interpreted as responses to variations in vertical accretion, stability of habitat types, invasive plant species, and herbivores. In the future, vegetation changes are likely to occur as a result of the intrusion of brackish water and increased flooding associated with global climate change and sea level rise. This long-term study establishes a baseline from which potential future changes to tidal freshwater wetlands can be better understood. © 2012 Coastal and Estuarine Research Federation.

Cunningham H.R.,Natural History Society of Maryland | Davis C.A.,Natural History Society of Maryland | Swarth C.W.,Jug Bay Wetlands Sanctuary | Therres G.D.,Annapolis flyer cab
International Journal of Zoology | Year: 2012

Declines of amphibian and reptile populations are well documented. Yet a lack of understanding of their distribution may hinder conservation planning for these species. The Maryland Amphibian and Reptile Atlas project (MARA) was launched in 2010. This five-year, citizen science project will document the distribution of the 93 amphibian and reptile species in Maryland. During the 2010 and 2011 field seasons, 488 registered MARA volunteers collected 13,919 occurrence records that document 85 of Marylands amphibian and reptile species, including 19 frog, 20 salamander, five lizard, 25 snake, and 16 turtle species. Thirteen of these species are of conservation concern in Maryland. The MARA will establish a baseline by which future changes in the distribution of populations of native herpetofauna can be assessed as well as provide information for immediate management actions for rare and threatened species. As a citizen science project it has the added benefit of educating citizens about native amphibian and reptile diversity and its ecological benefitsan important step in creating an informed society that actively participates in the long-term conservation of Marylands nature heritage. Copyright © 2012 Heather R. Cunningham et al.

Delgado P.,Chesapeake Bay National Estuarine Research Reserve | Hensel P.F.,National Oceanic and Atmospheric Administration | Swarth C.W.,Jug Bay Wetlands Sanctuary | Ceroni M.,University of Vermont | Boumans R.,Afordable Futures LLC
Estuaries and Coasts | Year: 2013

A 115-year-old railroad levee bisecting a tidal freshwater marsh perpendicular to the Patuxent River (Maryland) channel has created a northern, upstream marsh and a southern, downstream marsh. The main purpose of this study was to determine how this levee may affect the ability of the marsh system to gain elevation and to determine the levee's impact on the marsh's long-term sustainability to local relative sea level rise (RSLR). Previously unpublished data from 1989 to 1992 showed that suspended solids and short-term sediment deposition were greater in the south marsh compared to the north marsh; wetland surface elevation change data (1999 to 2009) showed significantly higher elevation gain in the south marsh compared to the north (6 ± 2 vs. 0 ± 2 mm year-1, respectively). However, marsh surface accretion (2007 to 2009) showed no significant differences between north and south marshes (23 ± 8 and 26 ± 7 mm year-1, respectively), and showed that shallow subsidence was an important process in both marshes. A strong seasonal effect was evident for both accretion and elevation change, with significant gains during the growing season and elevation loss during the non-growing season. Sediment transport, deposition and accretion decreased along the intertidal gradient, although no clear patterns in elevation change were recorded. Given the range in local RSLR rates in the Chesapeake Bay (2.9 to 5.8 mm year-1), only the south marsh is keeping pace with sea level at the present time. Although one would expect the north marsh to benefit from high accretion of abundant riverine sediments, these results suggest that long-term elevation gain is a more nuanced process involving more than riverine sediments. Overall, other factors such as infrequent episodic coastal events may be important in allowing the south marsh to keep pace with sea level rise. Finally, caution should be exercised when using data sets spanning only a couple of years to estimate wetland sustainability as they may not be representative of long-term cumulative effects. Two years of data do not seem to be enough to establish long-term elevation change rates at Jug Bay, but instead a decadal time frame is more appropriate. © 2013 Coastal and Estuarine Research Federation.

Savva Y.,Johns Hopkins University | Swarth C.W.,Jug Bay Wetlands Sanctuary | Gupchup J.,Johns Hopkins University | Szlavecz K.,Johns Hopkins University
Canadian Journal of Zoology | Year: 2010

Using a mixed-effects model for 21 Eastern Box Turtles (Terrapene carolina carolina (L., 1758)) over three winters in Maryland, USA, we demonstrate that overwintering-site temperature was mainly related to air temperature. After controlling for air temperature, between-year variation accounted for 7%, between-turtle variation accounted for 3%, and variation owing to age class accounted for 1% of the total variation in overwintering-site temperature. Turtles showed overwintering-site fidelity and the location of overwintering sites did not depend on sex or age. According to the developed function, air temperature would have to increase by 3 8C over the overwintering period to raise the temperature of overwintering sites by about 1 8C, assuming no changes in other environmental factors; this level of warming is not expected until 2070-2090 according to general climate circulation models.

Cordero G.A.,Jug Bay Wetlands Sanctuary | Cordero G.A.,Iowa State University | Reeves R.,Jug Bay Wetlands Sanctuary | Reeves R.,Iowa State University | Swarth C.W.,Jug Bay Wetlands Sanctuary
Chelonian Conservation and Biology | Year: 2012

The aquatic movement patterns and home-range size of the Eastern Mud Turtle, Kinosternon subrubrum, have received little attention. We radio-tracked 5 adult females and 5 adult males during 2 yrs in the Mid-Atlantic region of the United States. Our mean estimates of home-range size (18.6 ± 23 ha in 2008 and 16.3 ± 16.3 ha in 2009) and maximum aquatic distance traveled (815 ± 455 m in 2008 and 774 ± 331 m in 2009) suggest that K. subrubrum is highly adept at movement in aquatic environments. © 2012 Chelonian Research Foundation.

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