Dec. 17, 2014
Changing of the guard at Rice Rivers Center
The VCU Rice Rivers Center would like to thank retiring Board of Trustees Chairman Daniel Fort for all his years of service to the Center and the University, including a number of years as Chairman. We are delighted that Dr. Fort will continue to serve on the Rice Rivers Center Board and extend many, many thanks for his passionate devotion and support for the research, scholarship, outreach and stewardship practiced at and through Rice.
The gavel has been passed to new chairman, Mr. Brooks Smith. As secretary/treasurer of VIRGINIAforever and a partner at Troutman Sanders, he brings a depth of experience and enthusiasm that will enable him to lead the organization through the next exciting phase that will include construction of a state-of-the-art research building.
The VCU Rice Rivers Center extends hearty thanks to both of these gentlemen for their faithful service.Tweet
Dec. 17, 2014
VCU Rice Rivers Center receives award
On December 9, Rice Rivers Center’s VA Oyster Shell Recycling Program, led by Todd Janeski, was presented with a 2014 Virginia Green Travel Star Award for Most Innovative Project at the Annual Virginia Green Travel Conference in Richmond, VA. We owe this award to the hard work of our volunteers, partner businesses and organizations, and we thank them for their support.
Dec. 17, 2014
Tracking a shorebird to the ends of the earth
VCU Rice Rivers Center collaborator: Center for Conservation Biology
By Fletcher Smith
The journey begins in darkness in Virginia with an early morning flight departing from the Norfolk International Airport in late May. The air is humid, and the days have been hot along the mid-Atlantic Coast. The first leg of the trip is to Toronto, Canada. Subsequent flights take me through the Prairie Provinces (with an overnight stay), and finally on to Yellowknife, Canada. Yellowknife, the capital of the Northwest Territories, is where much of the logistical planning for the field season ahead takes place. The main focus of this collaboration between the Canadian Wildlife Service and The Center for Conservation Biology is the satellite tracking of whimbrels throughout their life cycle. The important task of rigging the satellite transmitters for deployment in the field takes place here in Yellowknife. The transmitters are placed in the carry-on luggage as they are irreplaceable if lost. The trip to Yellowknife has taken two days and nearly 3,000 miles are behind me at this point.
After a few days of last minute preparations, the team of biologists, technicians, and student interns leaves via airplane for the small town of Inuvik, located along a main branch of the Mackenzie River. This leg of the journey adds another 650 miles to the total, which is now at 3,650 miles and 4 days of travel time. Inuvik is where the final logistical steps take place; securing helicopter and Twin Otter flights into the bush, purchasing most of the food we will eat for the next 6 weeks, loading up gear at the airplane hangar, filling up gasoline and propane containers, and packing other crucial supplies that will be used in the coming field season. The total weight of the gear approaches 2 tons, and some of it is redundant, but there will be no option to stop at the local convenience store to pick up necessary supplies after we are dropped in camp.
The next leg of the journey begins on the first good weather day (which can be few and far between this time of year), and the team splits into two groups, one going with the helicopter and one with the plane. The helicopter flight from Inuvik to the outer Mackenzie Delta is an eye opener. During this flight, the team will cross hundreds of miles of frozen rivers, lakes, and snow-covered ground. With daily average low temperatures at around minus 20 Fahrenheit between mid-November and early April, ice breakup in the delta can take a while. This intensely long, cold, dark winter is one reason that few people inhabit the northern Arctic region. The spring and summer are best characterized by light. The sun never sets during the field season, and the ice and snow quickly thaw in the midnight sun. The average temperatures during the field season are between 40 and 60 Fahrenheit, relatively balmy compared to the deep cold of winter.
Frozen tundra in early June 2012 on the Mackenzie Delta. Photo by Fletcher Smith.
A view of our base camp in early June 2013. Our igloo like structure is visible just above the flooding waters in the center of the picture. The antennae in the foreground is a decommissioned communication tower that has been home to nesting Rough-legged Hawks, Ravens, and Gyrfalcons in different years. Photo by Fletcher Smith.
One team helps to unload the plane at a remote landing strip appropriately named Camp Farewell. The other team flies via helicopter to the gravel pad that will be home for the next 6 weeks. The process takes a full day, with the helicopter bringing in loads of gear hanging from a sling from Farewell to the field campsite. After the gear is dropped, the team puts together the equipment that will be used throughout the field season to collect data on nesting shorebirds. All supplies are distributed, including GPS units, pens, pencils, field notebooks, cameras, and banding equipment. The main kitchen area is set up in an igloo-like structure that allows respite from the biting insects. The storage tent is erected and all the food (calculated to be 5 pounds of food for each person each day!) is placed inside. The sleeping tents are placed on the far end of the pad, and a bear fence is erected around them. The possibility of having a bear come into camp to investigate the food tent or gasoline cans is very real, so those items are kept as far away from our sleeping tents as possible. We have put another 120 miles behind us, and can go no further north without swimming in the Beaufort Sea. The journey has taken about a week so far, and nearly 4,000 total miles are behind me.
The whimbrel’s migration to breeding grounds started just before my departure from Norfolk on that late May morning. The birds originated from wintering grounds in Brazil, where they spent 7 months in the Gulf of Maranhão region. There they fattened up for the journey north. Whimbrels complete the almost 4,000 mile journey to North American staging grounds in about 5 days. They arrive exhausted, and must build up fat immediately. The two stopover sites for the Mackenzie Delta breeding population are quite different. Along the Atlantic Coast, the vast coastal marshes of Virginia, South Carolina, and Georgia host the greater part of the Atlantic migrant population, where they feast on the seemingly endless supply of fiddler crabs. The Gulf Coast migrants stage between Mexico and Louisiana, using habitat ranging from crawfish farms and rice impoundments to natural coastal marshes for foraging and roosting. The Gulf Coast birds have a more varied palate, with fiddler crabs, crawfish, and marine invertebrates making up the majority of the diet at this stopover site. The birds will stay at these sites for close to a month, building up fat reserves and preparing for the next leg of their journey.
Migration begins when the pangs of Zugenruhe become too much to suppress. The birds leave the Atlantic Coast staging areas during a relatively short window; more than 90% of the birds leave within a 5 day period in the latter part of May. Many thousands are observed annually during this time in coastal Virginia. During the 2014 season, a new record of 8,192 individual whimbrels was counted, and nearly 6,000 of that total were observed between the 24th through 26th of May alone. The birds fly from the Atlantic Coast to the breeding grounds, covering the 4,000 miles to the Mackenzie Delta in a 5 day non-stop flight, quicker than it takes a biologist to cover the same distance (although biologists stop along the way to eat, sleep, and drink). The Gulf Coast whimbrels utilize a different migration strategy. They depart the Gulf Coast habitats in early May, stopping for short periods along the Platte River in Nebraska and in the irrigated farmlands of southern Alberta and Saskatchewan. The final 1,500 mile flights to the breeding grounds take place in the third week of May.
Map detailed routes taken to the Mackenzie Delta. Shown are tracks from two migrating whimbrels (a Gulf Coast and an Atlantic Coast migrant) and the track the biologist took getting there. Photo by Fletcher Smith.
Satellite tagged whimbrel. Photo by Fletcher Smith.
Once the whimbrels (and other shorebirds) and biologists converge on the same marsh-dominated breeding grounds of the outer Mackenzie River Delta, the real work begins. As part of the Arctic Shorebird Demographic Network (ASDN) and the Program for Regional and International Shorebird Monitoring (PRISM) programs, the Mackenzie Delta camp monitors the breeding success, population densities, annual survival, and other important parameters that are necessary in answering questions regarding population declines of shorebirds breeding in the Arctic regions.
After locating a nest, a walk-in trap is placed over the nest and the whimbrel is trapped within minutes upon returning to incubate. The bird is held by one of the researchers while the harness for the satellite transmitter is custom fitted. After she is released and continues to incubate her eggs, the nest is monitored until the eggs hatch or fail; nest failure is usually caused by predation by arctic fox, raven, or jaeger. In both 2012 and 2013, nest success rate was near zero for whimbrels, but in 2014 it was a boom year. Over 50 percent of the nests hatched and many chicks were observed in the marshes. One possible explanation for the uptick is that there may have been a good number of lemmings in the nesting area in 2014. Although lemmings are tough to see in the marshy habitat, two were observed being captured in the Delta by a single parasitic jaeger, each within minutes of one another, suggesting that an abundance of prey allowed the whimbrels relief from the attention of the predators that had been feeding on shorebird eggs the previous two seasons.
Whimbrel nest. Most nests have 4 eggs and are lined with horsetail and grasses. Photo by Fletcher Smith.
A satellite tagged whimbrel shortly after capture. Photo by Fletcher Smith.
A dark morph Parasitic Jaeger hunting the marsh. Photo by Fletcher Smith.
Recently fledged Gyrfalcon chicks at the decommissioned communications tower site. Gyrfalcons are one of the few sources of adult whimbrel mortality on the breeding grounds. Photo by Fletcher Smith.
After the nest monitoring and trapping of shorebirds is finished, we begin process of breaking camp, while excess food or gas is given to local people passing by on their way to hunting camps along the outer coast. Data is squared away and equipment carefully packed. With luck, the departure date will have good weather to avoid any delays home. The distant thumping of the rotors of a helicopter signal that our long journey back home has begun, and our hearts are glad with the anticipation of taking a hot shower and soon seeing loved ones.
Shortly after we leave field camp, the whimbrels will depart the Mackenzie Delta en route to their winter destination in Brazil to complete the loop on their astounding 14,000 mile annual migration. The tracking project has brought to light whimbrel behavior that challenges previously held beliefs about the migration routes of these birds. The overlap between the Mackenzie Delta population and the Hudson Bay population on the wintering grounds and Atlantic Coast staging areas was completely unknown prior to this study. Several critically important staging areas have been discovered because of this tracking project. The Center for Conservation Biology continues to lead whimbrel conservation research and plans are underway to work with these magnificent fliers in 2015.
The Arctic is characterized by plants with showy flowers, mosquitoes, and the routine threat of bad weather. Photo by Fletcher Smith.
The Low-centered Polygon habitat as we depart the delta. Notice the ridges are still apparent, but that the centers of the polygons have mostly dried. The delta quickly turns from frozen or flooded to vast expanses of green marsh. Photo by Fletcher Smith.
Dec. 10, 2014
Red knots receive listing under the Endangered Species Act – Virginia to play critical role in recovery
VCU Rice Rivers Center Publication
By Bryan Watts
In a press conference held on December 9, 2014, Service Director Dan Ashe announced the decision by the U.S. Fish and Wildlife Service to designate the rufa subspecies of the red knot as threatened under the Endangered Species Act. A “threatened” designation recognizes a significant risk of becoming endangered throughout all or a portion of a species’ range. The announcement concludes a multi-year, comprehensive assessment of available information on both the population and potential threats, including coastal development, climate change and declines in horseshoe crab eggs – a key prey resource within Delaware Bay.
Rufa red knots have one of the longest migrations known to science. From breeding grounds in the high arctic, a portion of the population migrates to winter grounds on the tip of South America, a round-trip distance of over 20,000 miles. Like many shorebirds, these extreme migrants require concentrated food resources to prepare themselves for long flights. Deterioration of prey resources and foraging conditions within refueling sites is believed to have played an important role in their decline. Since the early 1980s the population has declined by more than 75 percent.
Red knot captured along the Virginia Barrier Islands during spring migration. Photo by Bryan Watts.
Data collected in Virginia played a significant role in the listing process. Since 1994, Bryan Watts (Director of The Center for Conservation of Biology at the College of William & Mary and Virginia Commonwealth University) and Barry Truitt (Chief Conservation Scientist for the Virginia Coast Reserve of The Nature Conservancy) have conducted weekly aerial surveys of shorebirds along the outer coast of Virginia during the spring migration season. The results of these surveys were provided to the Service and have been used both in listing deliberations and in the ongoing designation of critical habitat for the species.
Virginia will play a critical role in the stabilization and recovery of the rufa population. Each spring, the Virginia Barrier Islands provide a refueling site to 30-50 percent of the entire population. Birds stage here before embarking on their final flight to arctic breeding grounds. Unlike the highly developed coastlines of New Jersey to the north and North Carolina to the south, more than 95 percent of the Virginia Barrier Islands are in protective ownership by The Nature Conservancy, the U.S. Fish and Wildlife Service and the Commonwealth of Virginia. This pristine coastline provides a much-needed oasis for the birds during their northward migration.
In a forthcoming paper to be published in the Journal of Wildlife Management, Watts and Truitt outline the importance of Virginia to staging knots and sound an urgent alarm. Unlike the well-known staging area in Delaware Bay where knots feed on horseshoe crab eggs, knots staging in Virginia feed on intertidal mollusks. In most years, blue mussels are the food of choice.
Spat of the blue mussel on intertidal peat along Cedar Island in Virginia
The distribution of blue mussels is undergoing a catastrophic shift due to climate change. Blue mussels are extremely sensitive to warm seas, and over the past 50 years their range has been contracting northward at an average rate of 7.5 kilometers (4.7 miles) per year. Virginia is now within the trailing edge of this range, suggesting that within the relatively near term, knots may no longer have access to this resource. The loss of blue mussels may have a much greater impact on the migration system of the red knot than the well-publicized harvest of horseshoe crabs.
Other red knot news stories:
- Red knot stopover ecology on VA's Barrier Islands
- Conservation in conflict: peregrines vs red knots
- Red knot resight data indicates flux between two migration staging areas
- Red knot numbers remain strong along the Virginia Barrier Islands
- Spring shorebird migration along the lower Delmarva Peninsula: The 2010 Season
- The business of shorebirds
- Spring shorebird surveys continue to count
- Flying with shorebirds
- Red knot decline spreads to Virginia
Nov. 12, 2014
Three Chopt Garden Club visits Rice Rivers Center
On October 28, the Three Chopt Garden Club held their membership meeting at the Rice Rivers Center. It was a glorious day to experience the field station. Former James River Park System Manager/Naturalist, Ralph White, gave the keynote speech on the history and value of the James River. Catherine Dahl, Director of Development and Special Projects for Life Sciences gave a brief overview of the Center and how it fits in with the overall mission of river stewardship worldwide. Members enjoyed tours of the property, including the waterfront and the wetlands.
Nov. 12, 2014
A forest out from under a lake
What WAS there? Once a vibrant wetland, then a well-stocked lake, and now in the process of restoration, Kimages Creek has experienced a great deal of change over the last 100 years. VCU graduate student Rick Ward is working to identify the flooded stumps in order that the wetland forest can be restored as well as possible to its former state.
Under the guidance of Dr. Ed Crawford, Ward has developed an 11-step process that begins in the wetlands, locating stumps by GPS and flagging them for mapping. A cross section of a stump (“cookie”) is carefully sawn from the stump, bagged and labeled. Once back in the lab, the cookies are dried in an oven and sanded on one face. After being given an approximate age by counting rings, the samples are placed under a microscope and compared to known samples, examining pores of early and late wood.
Using as reference a number of scientific publications, Ward works to discern the historical tree species found in the wetland area. He can determine which species were able to grow in both upland and wetland areas, and which species are “obligate wetland” and must grow there, like the Black Willow.
Starting with porosity and growth rings, there are 11 steps in Ward’s taxonomic identification code that can lead to identification of a genus of a tree. Because of the variety of conditions under which trees can grow, narrowing down to the species isn’t always possible.
So far, 46 extant species have been found, with the Sweet Gum tree being the most prevalent species along the edge of the wetlands. In terms of the historical forest, Ward and his team have only identified 15 species that comprise the over 5,000 stumps that have been located. The Nature Conservancy has been helping VCU Rice Rivers Center to restore the wetlands, having planted approximately 25,000 trees and shrubs thus far.
It was 1862 when Confederate and Union troops pulled out of the area, having clear cut the trees for fuel and sight lines for battle. Based on his research, Ward estimates that it took approximately 35 years for the forest at Kimages Creek to start flourishing once again. And now, with the help of The Nature Conservancy, Dr. Crawford, and Richard Ward, as well as other graduate and undergraduate students, the wetlands at Kimages Creek are well on their way to returning to their natural state for the first time in over 100 years.
Nov. 12, 2014
Shell recycling update – don’t chuck that shuck!
The Rice Rivers Center’s Virginia Oyster Shell Recycling Program (VOSRP) has been very active recycling used shell, bringing more restaurants into the program, and generating a great deal of interest. We were invited to participate in Governor McAuliffe’s Virginia Oyster Trail Event at the Governor’s Mansion, kicking off an exciting initiative to encourage oyster-wine tourism in Virginia. Our “shuck buckets” were everywhere, and the Governor himself was notably enthusiastic about adding his used shells to the collection. At a follow-up event, he asked for the shuck buckets and was pleased to know we were participating.
Governor McAuliffe enjoys an oyster, then seeks out our shuck bucket
Other events have included Shockoe on the Half Shell, Union Market’s “Eat Oysters! Drink Beer!” event, and Fire, Flour & Fork. Additionally, the Richmond Folk Festival featured a tent dedicated to the Virginia Oyster where World and Virginia champion oyster shuckers and sisters, Deborah Pratt and Clementine Macon-Boyd, kept sibling rivalry alive in an oyster shucking competition. The VOSRP collected shell there and interacted with participants of the Folk Festival, many of whom were VCU alumni.
The most recent partners added include The Savory Grain, Pomegranate, Westwood Club and Deltaville Oyster Co.
For up-to-the-minute information on this program, "Like" the Rice Rivers Center Facebook page and follow us on Twitter (@VCURiceRivers).
Nov. 12, 2014
VCU Rice Rivers Center and Virginia Green
The Rice Rivers Center is now a member of the Virginia Green program, demonstrating that we are committed to minimizing our impact on the environment. For more information, see the program’s Web page at http://www.deq.virginia.gov/Programs/PollutionPrevention/VirginiaGreen.aspx.
Nov. 12, 2014
VCU Rice Rivers Center accepted into important network
Earlier this month, the Rice Rivers Center's application to join the Cooperative Ecosystem Study Unit (CESU) was accepted by a unanimous vote of its members. Based in Washington, D.C., the CESU is network of federal agencies and academic institutions working together to conduct research and restoration for the Chesapeake Bay watershed. With funding from CESU, VCU faculty will begin avian and herptofauna surveys of Fort A.P. Hill in early 2015. These baseline surveys will support future conservation activities by base personnel and will provide valuable field experiences for graduate and undergraduate students in Biology and Environmental Studies. For more information on this organization, please visit http://www.cesu.psu.edu/.
Nov. 12, 2014
Nitrogen Retention in a Restored Tidal Stream (Kimages Creek, VA) Assessed by Mass Balance and Tracer Approaches
VCU Rice Rivers Center Publication
The VCU Rice Rivers Center congratulates Drs. Paul A. Bukaveckas and Joseph Wood on their publication: ”Nitrogen Retention in a Restored Tidal Stream (Kimages Creek, VA) Assessed by Mass Balance and Tracer Approaches”, published in the Journal of Environmental Quality.
The abstract reads as follows:
Tidal streams are attractive candidates for restoration because of their capacity to retain nutrients from upland and estuarine sources. We quantified N retention in Kimages Creek, VA, following a dam breach that restored its historical (pre-1920) connection to the James River Estuary. Estimates of N retention derived from mass balance analysis were compared to tracer-based retention estimates obtained by injecting NH4Cl during an incoming tide and measuring recovery on the outgoing tide. The injection experiments showed that dissolved inorganic N (DIN) retention in the restored tidal and nontidal segments was similar to nearby streams and previously published values. These data suggest that the stream has attained expected levels of functioning less than 2 yr after restoration despite 80 yr of impoundment. The mass balance analysis provided additional information for restoration assessment as this approach allowed us to track multiple N fractions. These results showed that DIN retention was offset by export of total organic N resulting in net loss of total N from the restored creek. Seasonal variation in DIN retention was significantly and positively related to tidal exchange volume and ecosystem metabolism (gross primary production and respiration). Our findings show that existing methods for measuring nutrient retention in nontidal streams can be adapted to the bidirectional flow patterns of tidal streams to assess restoration effectiveness.
Bukaveckas, Paul A. and Wood, Joseph. (2014) Nitrogen Retention in a Restored Tidal Stream (Kimages Creek, VA) Assessed by Mass Balance and Tracer Approaches. Journal of Environmental Quality, 2014, 43:1614–1623. http://dx.doi.org/10.2134/jeq2013.12.0481.
Restored tidal segment of Kimages Creek following dewatering and revegetation of former lakebed
Nov. 12, 2014
Local Habitat, Global Impact: Anderson Gallery walk
The “Local Habitat, Global Impact” field trip to the VCU Rice Rivers Center on October 25 was a big success! Sponsored by the Anderson Gallery, approximately 30 participants heard from four researchers about their work and how it relates to climate change.
Chris Gough demonstrates methods for researching carbon sequestration
Scott Neubauer discussing wetland restoration and sea level rise
Lesley Bulluck explains her work with migratory birds
James Vonesh at a mesocosm, explaining his work with amphibians
Nov. 11, 2014
Exposure to the Cyanotoxin Microcystin Arising from Interspecific Differences in Feeding Habits among Fish and Shellfish in the James River Estuary, Virginia
VCU Rice Rivers Center Publication
The VCU Rice Rivers Center congratulates Drs. Joseph D. Wood, Rima B. Franklin, Greg Garman, Stephen McIninch and Paul A. Bukaveckas, and Aaron J. Porter on their publication: “Exposure to the Cyanotoxin Microcystin Arising from Interspecific Differences in Feeding Habits among Fish and Shellfish in the James River Estuary, Virginia”, published in Environmental Science and Technology.
The abstract reads as follows: The cyanotoxin, microcystin (MC), is known to accumulate in the tissues of diverse aquatic biota although factors influencing exposure, such as feeding habits and seasonal patterns in toxin production, are poorly known. We analyzed seasonal variation in the MC content of primary and secondary consumers, and used dietary analysis (gut contents and stable isotopes) to improve understanding of cyanotoxin transport in food webs. Periods of elevated toxin concentration were associated with peaks in the abundance of genes specific to Microcystis and MC toxin production (mcyD). Peak toxin levels in consumer tissues coincided with peak MC concentrations in seston. However, toxins in tissues persisted in overwintering populations suggesting that potential health impacts may not be limited to bloom periods. Interspecific differences in tissue MC concentrations were related to feeding habits and organic matter sources as pelagic fishes ingested a greater proportion of algae in their diet, which resulted in greater MC content in liver and muscle tissues. Sediments contained a greater proportion of allochthonous (terrestrial) organic matter and lower concentrations of MC, resulting in lower toxin concentrations among benthic detritivores. Among shellfish, the benthic suspension feeder Rangia cuneata (wedge clam) showed seasonal avoidance of toxin ingestion due to low feeding rates during periods of elevated MC. Among predators, adult Blue Catfish had low MC concentrations, whereas Blue Crabs exhibited high levels of MC in both muscle and viscera.
Wood, Joseph D., et al. (2014) Exposure to the Cyanotoxin Microcystin Arising from Interspecific Differences in Feeding Habits among Fish and Shellfish in the James River Estuary, Virginia. Environmental Science & Technology, 2014, 48, 5194-5202. http://dx.doi.org/10.1021/es403491k
Rangia cuneata (wedge clam), approximately 5-8 years old
Nov. 11, 2014
New logo: VCU Rice Rivers Center
VCU Rice Rivers Center is methodically transforming everything that carries the Rice Rivers Center name, as part of the ongoing effort to clarify the public’s understanding of our mission. The latest change is our trusty “Rice Car”, as well as our fleet of research boats.
VCU Rice Rivers Center’s Director, Len Smock, and the "Rice Car"
Nov. 11, 2014
Influence of Substrate Quality and Moisture Availability on Microbial Communities and Litter Decomposition
VCU Rice Rivers Center Publication
The VCU Rice Rivers Center congratulates Drs. David J. Berrier, Morgan S. Rawls, Shannon Leigh McCallister and Rima B. Franklin on their publication: “Influence of Substrate Quality and Moisture Availability on Microbial Communities and Litter Decomposition”, published in the Open Journal of Ecology.
The abstract reads as follows:
The main source of carbon (C) to soil stocks is plant litter, the decomposition of which is controlled by a mixture of physical, chemical, and biological processes. Bacteria and fungi are the dominant biota responsible for decomposition, yet we know very little about their respective contributions or how community dynamics may be affected by litter quality. This study sought to gain a better understanding of the variable relationships between organic matter decomposition, litter quality, and microbial community composition, with a specific focus on distinguishing bacterial and fungal dynamics. Experiments were conducted under contrasting hydrological conditions, comparing a wetland with an upland forest environment. Decomposition of native vegetation was monitored in addition to breakdown of a common substrate (Acer rubrum (red maple) leaves) placed in both environments. In situ incubations lasted 16 months, and were sampled at ~3-month intervals. Regardless of site, maple litter decomposition proceeded at a similar rate, though we did observe differences in litter quality over time (C:N, %N, solubility of organic C). For the upland site, native litter decomposed more slowly than the maple did. At the wetland site, both litter types decomposed at a similar rate which, surprisingly, was faster than either litter type at the upland site. This finding could be attributed to water-limitation at the upland site and/or stimulation of decomposition at the wetland site due to allochthonous nutrient inputs or organic matter priming. Substrate induced respiration (SIR) was measured for native litter incubated at each sampling site, and the relative contributions of bacteria and fungi were compared. No consistent major differences were detected across these microbial groups, though we did observe much higher rates of SIR at the wetland site compared to the upland site. Community structure of each microbial group was examined via terminal restriction fragment length polymorphism (TRFLP), which revealed dramatic temporal shifts for both groups at both sites. In general, these results indicate a long-term effect of both litter type and environmental conditions (site) on the bacterial community, but show only environmental effects on the fungal communities. This suggests that different environmental conditions allow microbial communities to uniquely approach decomposition of leaf litter components.
Leaf litter along Civil War earthworks, VCU Rice Rivers Center