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February 2, 2023 - World Wetland Day

Today is World Wetlands Day! To celebrate, we’ve put together a little information about the various wetland ecosystems at Hirundo.

We can’t imagine life without water, quite simply because life itself isn’t possible without it! Liquid water is a defining characteristic of our planet. Most of the Earth’s surface is covered with oceans and seas with only about 3% being “fresh” water. This fresh water is unevenly distributed, as much of it resides in the Great Lakes, and large swaths of the world are desert.

Because water is such an essential part of life on Earth, it is not surprising that ecosystems have evolved around the amount and type of water available. Scientists have classified several types of terrestrial ecosystems based on water availability, known as: wetlands! The most common wetlands include bogs, marshes, swamps, floodplain forests, and vernal pools. Each wetland is home to unique plant and animal communities.

As a wildlife refuge, Hirundo is very fortunate to have many types of wetlands. This increases the biodiversity here, which offers stability to our ecosystems. Ecosystems with high biodiversity can recover more easily from disease and disaster than ecosystems with low biodiversity.

Bogs are found in northern climates, especially in those that were historically covered by glaciers (like Maine!). They form when depressions in the ground fill with still water and accumulate dead plant materials. The plants that grow in bogs have adapted to thrive where nutrients are scarce, as bogs do not receive nutrients from ground water. Bacterial decomposition in bogs is very slow, due to a lack of oxygen resulting in the build-up of organic matter. This build-up is referred to as peat. Bogs have been mined for their organic matter because it can be burned as a fuel or harvested for mulch. Carnivorous plants are found here - they eat insects because they cannot obtain enough nutrients to survive on photosynthesis alone. Such plants include sundews, pitcher plants and bladderworts. There are a few animal species that have come to inhabit bogs, such as muskrats, mink, rails, and woodcock. Hirundo’s bog is nearly inaccessible because it is surrounded by other wetlands.

Floodplain Forests are flooded annually in Maine, typically during the period when the winter snow melts and the spring rains begin. These areas may also flood during periods of extreme rain at other times of the year. The trees that grow here must be able to withstand waterlogged soil for several months a year, and so they have evolved the ability to survive on minimal oxygen. This includes trees like red maple, brown ash, American elm, and others. However, small shrubs cannot survive, and so remain absent. In floodplain forests, water flow is slowed down, which reduces land erosion downstream. It is mostly dead vegetation that is swept into the water, and this organic matter becomes the basis for the aquatic food chain. Bacteria feed on the vegetation, tiny aquatic animals feed on the bacteria, and so on - all the way up the chain. At Hirundo, silver maples dominate these wetlands. The silver maple floodplain forest provides a breeding habitat for many important migratory birds, including the northern waterthrush, belted kingfisher, veery, yellow warbler, great crested flycatcher, Baltimore oriole, and barred owl. Many amphibians will breed in the leaf litter, such as spring peepers, spotted- and blue-spotted salamanders. The silver maple floodplain forest can be found along the shore of the Pushaw - you can view it from the entrance of the pond trail along Lac D’Or.

Marshes are found worldwide. They may be of the freshwater, brackishwater, or saltwater variety. Marshes are a popular habitat for many grass and low-growing shrub species. Here, the soil is nearly always waterlogged, so most trees cannot grow. Many of the plants here can bring air from their leaves to their oxygen-starved roots. Marshes serve as nurseries for many fish species, and are habitats for rodents (like beavers and muskrats), turtles, countless waterfowl, and wading birds. Marshes have the ability to slow the flow of water, reducing both flooding and erosion. This slower moving water sinks into the soil, essentially “recharging” the groundwater. At Hirundo, marshes are best observed by canoe along the Pushaw and Dead Streams!

Swamps are permanently saturated wetlands that contain a large volume of trees. In fact, a swamp is typically named for the main tree species that inhabits it (cypress swamps, red maple swamps, etc.). Swamps can be thought of as marshes with trees. Sometimes, the accumulation of soil in marshes can even result in the formation of swamps. Swampy soil is less saturated, so plants that require more oxygen can thrive. Swamps have their own characteristic group of trees, shrubs and perennial plants. Some of these you might find include sheep laurel, skunk cabbage, and common winterberry. Swamps can also make a good home for the rare wood turtle! As you canoe along the Pushaw Stream, you can observe marshes and swamps as they blend into one another.

Vernal Pools are temporary bodies of water found in wooded areas during the springtime. They are generally located in shallow depressions that fill with snowmelt and/or rain water. By mid-summer, they’ll usually have dried up. Many of these pools are where several amphibians breed in the spring. Wood frogs breed exclusively in vernal pools, as well as two species of salamanders: spotted- and blue-spotted. Individuals of these species return to the pool where they hatched to spawn, and thus long lineages are represented by specific pools. As such, the loss of a vernal pool can diminish the local amphibian population. Some of these amphibians travel hundreds of meters to return to where they started their life. They usually travel on wet spring evenings, mate and lay eggs, then return to the forest. Vernal pools are used for this aquatic reproduction because they are free of predatory fish that would otherwise feed on the eggs. Significant vernal pools are even protected by state law. You may find some throughout Hirundo’s forests! But as always, please stay on the marked trails and admire from afar.


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