Wildlife Center Classroom Series Wondrous Wetlands: Secrets of the Salt Marsh

Transcription

1 Wildlife Center Classroom Series Wondrous Wetlands: Secrets of the Salt Marsh Wednesday September 14, 2016 Good afternoon everyone, and an official welcome to today s Wildlife Center Classroom Series: Alex Wehrung, WCV Hi Alex! Looking forward to class! Hi, there! Let s jump right in! We ll start with the basics: What is a wetland, anyways? Comment From Dave in Missouri Sounds awesome, I will have to scroll back, thank you Alex! Wildlife Center Classroom Series: Wondrous Wetlands: Secrets of the Salt Marsh Page 1

2 Chances are, most of you are yelling Land that s wet! at your computer screens right now -- and you d be correct! Comment From BarbG "swampy area" The soggy areas around Areas around bodies of water. Comment From CAL But can't wetlands also be land that is not obviously wet? I think they play an important role in keeping the aquifer clean. The Environmental Protection Agency s official definition reads like this: A wetland is an area of land where saturation with water is the dominant factor determining the nature of soil development, types of plant communities, and types of animal communities. That makes sense. Wetlands might look like Alex Wehrung, WCV Wildlife Center Classroom Series: Wondrous Wetlands: Secrets of the Salt Marsh Page 2

3 The EPA goes into even more detail by adding that under normal circumstances, wetlands support a prevalence of vegetation typically adapted for life in saturated soil conditions. Basically, three things must be present in an area for it to be considered a wetland: Firstly, a hydroperiod: the period of time during which the area is covered by water. This graph shows examples of what the average water level might look like for different types of wetlands throughout the year: Wildlife Center Classroom Series: Wondrous Wetlands: Secrets of the Salt Marsh Page 3

4 As you can see the amount of water increases quite a bit during summer months, when most regions are likely to experience a rainy season. I always think of the saltwater wetlands. The marshy areas that are covered when the tide is in and then more open when the tide is out.love those areas! I do too, it's easy to forget that wetlands can be salt or fresh water, in the mountains, on the shore, next to a pond in your backyard, etc. The second factor that must be present for an area to be considered a wetland is hydric soil: soils that are sufficiently wet in the upper part to develop anaerobic conditions during the growing season. Anaerobic comes from the Greek root words meaning without and air in this case, without oxygen. When water covers soil that has high amounts of clay and silt, oxygen is unable to move freely or permeate -- throughout the layers. This scale shows just how small clay and silt particles are compared to sand or gravel: Wildlife Center Classroom Series: Wondrous Wetlands: Secrets of the Salt Marsh Page 4

5 Comment From BarbG very interesting Wow! Tiny! The smaller the particle, the more dense the soils will be. Comment From Dede Very interesting. I always think of clay as large...guess it's just the stickiness of it. Determining whether a soil is hydric can be quite a science, but there are a few signs that can be easily identified. One sign is gleying (sometimes called mottling), a dark rust color in the soil that s caused by undrained water: You can also feel the soil. If you have a lot of clay content and you can mold it, then there is a chance that you have hydric soils. Wildlife Center Classroom Series: Wondrous Wetlands: Secrets of the Salt Marsh Page 5

6 Personally, I think the easiest to identify hydric soil is to take a deep breath sulfur (which can smell like rotten eggs) is produced by anaerobic bacteria decomposing organic matter in the soil. Pee-yew! Last, but not least, the final factor that must be present for a place to be a wetland is hydric plants. These are plants that have specific adaptations to live in areas with both hydroperiods and hydric soils. Like cattails? Love them! Yep! Cattails are great examples of hydric plants! Plants in these areas could face long periods where there is little to no oxygen, exposure to moving water, and even varying levels of salinity that are toxic to many plants. How do they do it? One way is through adventitious roots that grow above the soil to assist with the transfer of oxygen. This actually isn t a wetland plant (it s corn), but it s a good example of what some plants do if their roots are growing in saturated soils. Comment From Texas Gal Wildlife Center Classroom Series: Wondrous Wetlands: Secrets of the Salt Marsh Page 6

7 I love the cypress trees that grow around the water Comment From Guest like cypress trees with their knees? Also hydric plants, yes! Cypress trees grow knees that provide stability and absorb nutrients from the atmosphere: Comment From MaryinRichmond and mangroves? Definitely mangroves. They're roots are sometimes referred to as "buttresses" because they aid the tree in structural support. Comment From BarbG all kinds of reeds and waterlilies Some plants like the turtlehead, a member of the figwort family, have flat seed pods that are perfect for being carried away by moving water: Wildlife Center Classroom Series: Wondrous Wetlands: Secrets of the Salt Marsh Page 7

8 Lots of grasses. The dominant type of vegetation is usually the easiest way to categorize that type of wetland an area is. Trees dominate freshwater swamps, grasses dominate the salt marsh, and mosses dominate bogs. For the rest this class, we ll be diving into the salt marsh! YAY! Salt marshes are coastal wetlands between land and salt or brackish water two very different environments that create a truly unique habitat when they come together. Comment From MaryinRichmond are estuaries a type of wetland? An estuary is another word describing areas where salt and fresh water meet, but if it has a hydro period, hydric soil, and hydric plants then yes - it is a wetland! Is this considered something different from an estuary? Only slightly- estuaries can occur wherever the water from a river or stream meets the sea. Sometimes, though, those areas aren't in the right climate for hydric plants to grow (freshwater melting from a glacier into the Arctic ocean, for example). Here's a good diagram of what salt marshes look like from above: Wildlife Center Classroom Series: Wondrous Wetlands: Secrets of the Salt Marsh Page 8

9 Regularly flooded by rising and lowering tides, salt marshes are difficult for most plant species to survive in. One of the few that can, though, dominates the landscape: Spartina alterniflora Commonly called cordgrass, it is an emergent plant rooted beneath the water level, but has leaves and stems extending out of the water during high tide. In the picture above, you can see very clearly where the high tide reaches - the green tops of the cordgrass are always above water. Comment From Sweetpea We have sweet grass here in the low content that is used to make baskets I've heard cordgrass be called sweet grass in the low country, too! Spartina alterniflora sheds excess salt through its stem, and has thick, web-like roots to help the plant dig-in while the tides and currents are constantly moving. Salt marshes are incredibly productive ecosystems! Because salt marshes develop between terrestrial and marine environments, they result in biologically diverse communities. What kind of critters live in the salt marshes? Wildlife Center Classroom Series: Wondrous Wetlands: Secrets of the Salt Marsh Page 9

10 TONS! Birds, crustaceans like crab and shrimp, otters, muskrat, fish, snakes, oysters, mussels and clams, marine worms, jelly fish... It s estimated that about 4.5 lbs. of biomass (plants, animals, organic matter, etc.) per meter is produced every year in salt marshes. Research shows this meets and sometimes exceeds biomass production per meter in tropical rainforests! Comment From MaryinRichmond The marsh at York River State Park here in Virginia is a great example, right? It definitely is! Aside from being productive and biodiverse ecosystems, salt marshes are of incredible value to humans. For one, salt marshes are habitats that act like an enormous filter; Grasses throughout the marsh remove pollutants such as herbicides, pesticides, and heavy metals from the water flowing through it. I feel the need to go sit and watch a salt marsh for a while! I think everyone should visit one! The huge network of plants also helps to reduce coastal erosion by acting as a buffer zone between the open ocean and inland areas especially during storms. Studies have shown that more than half of normal wave energy is dissipated within the first 3 meters of encountering marsh vegetation, such as cordgrass. Salt marshes also act like a gigantic sponge. Grasses and drastically slow down moving water from rainfall and river drainage, allowing more time for it to be absorbed into the soil. Wildlife Center Classroom Series: Wondrous Wetlands: Secrets of the Salt Marsh Page 10

11 Slowing down the flow of water further improves its quality by allowing particles to settle and sink to the bottom. This helps to counteract coastal erosion by providing even more growing space for vegetation! Lastly, salt marshes serve as important habitats for hundreds of species of fish, shellfish, birds, reptiles and mammals. In fact, 75% of commercial fish species depend on these areas for their primary habitat, spawning grounds, or nursery areas. Migratory birds also rely on wetlands in the same way NASCAR drivers rely on pit-stops throughout a long-distance race; food, water, and shelter found in salt marshes help traveling birds cross the finish line in one piece. Comment From Brenda from Virginia Love the pit stop analogy! Don t forget about recreation! Salt marshes offer excellent areas for kayaking, fishing, and wildlife photography. Wildlife Center Classroom Series: Wondrous Wetlands: Secrets of the Salt Marsh Page 11

12 Comment From Melinda in NC I have had to catch up, but just wanted to throw this out there..i have cattails in my ditch. Then you just might have a wetland! Unfortunately, salt marshes and other wetlands have been and continue to be lost at a rapid rate due to human development. Comment From Brenda from Virginia What legal provisions are in place to protect salt marshes? The Clean Water Act is one way; it strictly enforces through federal law that environmentally significant water ways cannot be polluted or destroyed. It angers me too see wetlands taken over by human development! The Environmental Protection Agency also requires that major development projects (like a new suburb or shopping center) must first have a professional scientist evaluate how their construction plans will impact the environment. Despite all the important ecological services that would cost the public significant amounts of money to replicate, many entities do not understand their value. For example, did you know that Boston, Chicago, Miami, Central Park, NY, Houston, Washington D.C., and even Disney World are all built directly on top of wetlands? It makes sense that these areas were developed. Where you have wetlands, you have waterways. If you have waterways, you have commerce and wealth. Comment From BarbG that is amazing Wildlife Center Classroom Series: Wondrous Wetlands: Secrets of the Salt Marsh Page 12

13 Oh my word, no, I did not. Comment From Texas Gal I live in Houston...lots of wetlands and mosquitoes =) Luckily, there are many ways we can help "turn the tide" and conserve wetland areas: Using native species when planting trees, shrubs and flowers to preserve the ecological balance of local wetlands. Keeping surface areas that wash into storm drains clean from pet waste, toxic chemicals, fertilizers and motor oil, which can eventually reach and impair our wetlands. Using phosphate-free laundry and dishwasher detergents; phosphates encourage algae growth, which can suffocate aquatic life. And one of my favorites- Participating in programs that help protect and restore wetlands -- contact your local, state, or federal agencies, community groups, environmental organizations and other non-government organizations for information! Next time you happen to be near a wetland area, take a closer look! Smelly mud and a lot of grass may be all that the untrained eye will see, but now we know there are many more secrets beneath the surface just waiting to be discovered. I hope you enjoyed learning about wetlands and salt marshes with us this afternoon this concludes the session! Thanks for joining us, and we ll see you next time! Wildlife Center Classroom Series: Wondrous Wetlands: Secrets of the Salt Marsh Page 13