Tag Archives: wetlands

Amphibians: Rising in Fall

by Jeff Beane

To everything there is a season. The lives of most amphibians are particularly seasonally oriented. Amphibian literally means “double life” or “both lives,” referencing the dependence of these animals on both land and water. It’s not precisely true. Some amphibian species are entirely aquatic and some are exclusively terrestrial, defying the very definition of amphibian. But except for the fully terrestrial plethodontid salamanders in the genera Aneides and Plethodon, all amphibians in the Carolinas depend on either wetlands or permanent water for breeding.

Every amphibian species has a different life cycle and survival strategy. Some possess extreme seasonal adaptability, potentially breeding whenever weather conditions are favorable. Others breed at very specific times of year—some only in winter, others only in spring, and still others only in summer. This seasonal partitioning is one of many strategies serving to reduce competition, allowing multiple species to coexist. Fall is often thought of as a slow time or “down time” for many species, and this does include some amphibian species. But for others, fall is the most important time of year.

Marbled salamander (Ambystoma opacum) - North Carolina's state salamander - breeds only in the Fall. (Photo by Alvin Braswell)

One obligate fall breeder is North Carolina’s official state salamander—the marbled salamander, Ambystoma opacum. Salamanders in the family Ambystomatidae are collectively called “mole salamanders” because the adults are fossorial, spending most of their lives in burrows on land. Most mole salamanders have life cycles like those of our frogs and toads—they lay their eggs in water, the eggs develop into aquatic larvae, and the larvae develop into terrestrial juveniles. All six mole salamander species in the Carolinas (marbled, spotted, mole, tiger, Mabee’s, and frosted flatwoods) are heavily dependent on fish-free, ephemeral wetlands for breeding. While most deposit their eggs in these wetlands, usually in winter or early spring, marbled salamanders switch things up a little, moving into their breeding sites on rainy nights in late summer or early fall. They utilize a variety of ephemeral wetlands, including floodplain pools, borrow pits, and even ditches and logging ruts, but high-quality upland vernal pools provide the best breeding habitat. Males move into the breeding sites first, sometimes as early as late August. The females follow, usually in September or October. Typically, the pools are bone-dry when they arrive. Not only does this fail to disappoint the salamanders—it’s just what they’re hoping for. They will mate beneath surface litter in the dry pools, the male depositing a sperm packet called a spermatophore and the female retrieving it with her cloaca and retaining it internally to fertilize her eggs as they are deposited. She selects a log or other sheltering object in the dry pool basin and deposits her eggs in a cluster underneath. Then comes a waiting game. She remains with the eggs, attending them until fall or winter rains flood the pool, whereupon she abandons them and returns to her terrestrial burrow. The eggs hatch quickly once inundated, and the aquatic larvae begin developing with a head-start over the other species using the pool later that winter or spring.

Empheral pond at Raberdo Bog (Uwharrie National Forest, west-central Montgomery Co., NC) provides habitat for the mole salamander (Ambystoma talpoideum) (Photo by Alvin Braswell)

Marbled salamanders are not the only fall breeders. The rare frosted flatwoods salamander (Ambystoma cingulatum), still persisting in scattered localities in the South Carolina Lowcountry, typically breeds from October to December. This species also deposits its eggs terrestrially—although usually unattended—amid vegetation in the dry basins of ephemeral wetlands. Tiger and Mabee’s salamanders also may breed as early as October or November, or as late as March, depending on weather. They deposit their eggs (gelatinous masses for tigers, single eggs attached individually to leaves for Mabee’s) in water, so the ponds they use (often Carolina bays) must be flooded before they can breed. During droughts, they may miss breeding for a year, or even several consecutive years.

Spotted salamander (Ambystoma maculatum) (Photo by Alvin Braswell)

Several other amphibians that usually breed in winter or spring, can breed opportunistically in fall if conditions are favorable, especially following hurricane rains. These include the southern leopard frog, Carolina gopher frog, pine woods treefrog, eastern spadefoot, eastern newt, and little grass frog. In some (leopard frog, gopher frog, newt), the larvae will live in the pond all winter. But spadefoot tadpoles develop so rapidly that they will transform and leave before freezing weather, even if breeding occurs as late as October. Some plethodontid salamanders, including mud, red, two-lined, dwarf, and Chamberlain’s dwarf, may mate in fall, although their eggs are laid later in the winter. They are therefore often active on rainy autumn nights.

Fall may be a winding-down time for some creatures, but for certain amphibians it is a new beginning. On every day of the year, there is something important happening in our wetlands!

About the Author

Jeff Beane is the Herpetology Collections Manager at the North Carolina Museum of Natural Sciences in Raleigh, NC.  His research focuses on gathering basic information on the natural history, geographic distribution, and conservation status of all reptile and amphibian species in North Carolina.   More Info.

WRRI Annual Conference: Wetland Session

Carolina Wetlands Association and NC WRRI will host a Virtual Annual Conference session on wetlands research in North Carolina. The free webinar will offer updates on ongoing studies, as well as news on how wetlands are gaining further protections so they can continue to provide valuable ecosystems services.

  • Michael Burchell, NC State University, Removing detritus to rehabilitate older constructed wetlands used in wastewater treatment
  • Melinda Martinez, NC State University, Greenhouse gas emissions from standing dead trees in coastal forested wetlands
  • Brock Kamrath, NC State University, Preliminary assessment of nitrogen treatment in a tertiary constructed wetland following detritus removal

Wetlands in the Winter: What’s Happening?

Winter and early spring is an important time for wetlands across North and South Carolina. First, wetlands are easier to find in the winter with high rainfall and no vegetation growth allowing water to sit at the surface.  This standing water provides needed habitat for migrating birds and breeding amphibians. Also, lack of leaves and pesky mosquitoes make winter the perfect time to explore the different types of wetlands across the landscape.

Water Level (a.k.a. Wetland Hydrology)

Wetlands are defined by the amount, duration, and occurrence of standing water or saturated soil (referred to as wetland hydrology). Non-tidal wetlands like headwater wetlands, riverine swamps and pocosins fill with water in the winter and early spring until plants and trees start to grow and pump the water out to the atmosphere through evapotranspiration. If you explore a wetland in the winter, you may need to wear rubble boots to keep your feet dry.

Hydroperiod for several wetland types show surface water in the winter and early spring. (Source: National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. https://doi.org/10.17226/4766. )

Import Habitat for Migratory Birds

Wetlands across North and South Carolina provide refuge in the winter for migratory birds like snow geese and tundra swans that fly south to avoid harsh winters in the Northern US and Canada.  The loss of wetlands across the Southeast US has forced some species to adapt by feeding in fallow agriculture fields. Luckily, many state and federal lands across the Coastal Plain of the Carolinas provide vital habitat for these birds and create opportunities for us to catch a glimpse of these majestic animals.

Tundra swans at Lake Mattamuskeet (Photo by Alvin Braswell).

Where can you find tundra swans?

Breeding Grounds for Amphibians

Wetlands are also critical habitat for many reptiles and amphibians because they depend on water for part of their life. Most amphibians lay eggs under water or on moist land. Once the eggs hatch, the baby amphibians must live in water until they form lungs and leave the water as adults. Eggs of some species are laid in the fall and survive in a gel-like substance until wetlands fill with water.  Even as adults, wetlands are an important source of food for amphibians. Step carefully and keep your eyes looking down for signs of salamanders and other amphibians. To learn more about these creatures, join us at the NC Museum of Natural Science’s Reptile and Amphibian Day on March 14.  

Southern Leopard Frog (Rana sphenocephala) egg mass. (Photo by Alvin Braswell.)

Go Explore a Wetland!

Wetlands in the winter are working just as hard as they are the rest of the year and provide opportunities to see species that you can’t see other times of the year.  Here are some resources to help you find a wetland near you : 

Share pictures of your favorite wetland with us on Facebook!

Article written by Kim Matthews (kim.matthews@carolinawetlands.org).

Wetlands Matter: Networking and Information Sharing Event

Wednesday, November 28, 2018 from 5:30 PM – 7:30 PM

 

Come learn about the Carolina Wetlands Association and the work the organization is doing to advance the understanding, protection and enjoyment of wetlands throughout North and South Carolina.  Our 2019 calendars featuring our Wetland Treasures, magnets, and t-shirts will be available during the event.

AGENDA 
5:30    Networking Time

6:00    Guest Speaker: Derb Carter, Southern Environmental Law Center 
Mr. Carter will discuss the status of proposed changes the Waters of the U.S. rule and what that means for wetland protection and restoration.

6:30     Overview of the Carolina Wetlands Assocation
Learn about our efforts to get a Ramsar wetland designation in North Carolina, the Wetland Treasures of the Carolinas Program, and our effort to issue a State of the Wetlands report.

7:00    More Networking Time

7:30    Meeting Ends

Food and drinks will be provided!  Please register so we know you are coming.

 

INFLUENCES OF BEAVER ON FORESTED COMMUNITIES IN THE SOUTHEASTERN U.S.

Written by Dr. Carrie DeJaco

Prior to European colonization of North America, beaver (Castor canadensis) were abundant throughout most of the continent.  Estimates of pre-colonization beaver populations are between 60 million and 200 million individuals, with at least 20 million beaver-built dams.   By the year 1900, beaver had been extirpated from the eastern half of North America and the species was hanging on by small remnant populations in the west.

Reintroductions of beaver had begun in the southeastern U.S. by the 1940s.  With few predators and laws regulating hunting, beaver populations in North American have rebounded. By 1983, beaver were present in 80 of 100 counties in North Carolina but were still largely absent from the Broad, French Broad, Catawba, and Pasquotank river basins—mainly the Charlotte area and the region directly to the west and north of it.

The majority of studies on beaver in North America have been conducted in the northern states and Canada.  Larger scale effects found by these studies may be applicable here in the south, but many of the species-specific observations are irrelevant due to the difference in plant species between the northern and southern latitudes.  This review of the literature on the impacts of beaver includes the handful of studies conducted in the southeastern U.S.; larger scale patterns observed at northern latitudes will also be discussed, but species-level observations from northern studies will only be included if they are relevant to the southeastern U.S..

Click here to read the entire article.

Beaver dam, Franklin Co, ALB photo
Beaver Dam (Franklin County, NC) Photo by Alvin Braswell

Photo by Alvin Braswell

Beaver Lodge (Franklin County, NC) Photo by Alvin Braswell