The Benefits of Wetlands
The Benefits of Wetlands
Wetlands contribute to biodiversity and offer important ecosystem services for individuals, communities and society. They form a habitat for many wetland species and recreational areas, for example, for bird-watchers and hunters. Man-made and restored wetlands work as natural filters: they curb floods and stop nutrients and sediments in runoff waters from travelling further. A network of wetlands offers water birds the brood-rearing habitats they need. Restored rural wetlands are often also important for the landscape.
Watching Birds and Wildlife
Wetlands are a great destination for bird-watchers. Not only does a wetland established in a species-poor field offer welcome variety in the landscape but also a habitat for several species that have not been seen there before. Wetlands provide a fantastic opportunity to watch Horned Grebes building a nest or a Eurasian Hobby chasing dragonflies. On summer nights, you can hear a Reed Warbler’s even chattering from the reeds.
What makes a wetland built close to home more valuable to a bird-watcher is its easy accessibility and the fact that you no longer have to drive to the lake in the neighbouring municipality to see wetland species. Some wetlands also have bird-watching towers or lean-to shelters with a campfire site to serve recreational users. Wetlands built in your home district make wonderful destinations for bird-watching for the whole family or for school trips.
Although man-made wetlands are often also hunting destinations, bird-watchers have no need to avoid duck hunters, because there is space for everyone. Watching duck hunting and getting to know the hunters is an opportunity to learn to appreciate responsible Finnish hunting traditions and the considerable work hunters do voluntarily to maintain waterfowl habitats. Hunters are people who respect the environment and whose hard work in rural wetlands benefits a huge number of bird species.
However, if you prefer not to visit wetlands at the same time as duck hunters, this can be done: the duck hunting season doesn’t begin until the end of August, so trips to listen to the song of night birds will not be disturbed by shotguns. The best time to watch wetland birds is in the early and high summer, when you can be sure there are no hunters about. Even during the hunting season, duck hunting in Finland usually takes place just before twilight, so you are unlikely to bump into duck hunters at midday, even at the end of August.
According to studies, hunting is the most popular recreational activity in wetlands, and a desire to improve one’s own opportunities for hunting is the most important reason for establishing, restoring and managing wetlands. There is a clear connection between hunters’ nature management work and securing the continuity of hunting: by establishing habitats suitable for waterfowl and managing them actively, the local yield of water bird broods can be improved and consequently a strong basis for the ecological sustainability of hunting can be created.
Water birds, and especially their nestlings, have many enemies. The small predator species of foreign origin, the American mink and raccoon dog, may substantially weaken water birds’ success in reproducing by robbing eggs from their nests and hunting nestlings. To prevent the valuable work for the improvement of waterfowl habitats from going to waste with vanishing broods, special attention should be paid to organizing hunts for small predators and creating a sufficiently great catch rate in proportion to the population of small predators. As a part of the other management work of the wetland environment, successful hunts for small predators will benefit demanding species requiring immediate protection measures, as well as game birds.
Successful breeding alone will not, however, guarantee the strengthening of waterfowl breeding populations in rural wetlands, especially if the hunting yield is not based on a sustainable model. A good rule of thumb to follow is that the annual hunting mortality should roughly correspond to the yield of nestlings in the area. The most reliable estimation of annual maximum catches can be achieved with waterfowl counts that are repeated several times over a summer. These provide a good general view of the local waterfowl population and their annual reproduction success.
In addition to yield planning based on waterfowl counts, it’s a good idea to determine common rules for hunting in wetlands. These may concern, for example, temporal restrictions for hunting or establishing separate areas that are protected from hunting. Developing our self-regulation for hunting is the best way to prevent a premature migration from beginning, which will not only lengthen the active hunting season for waterfowl in Finland but also increase our national responsibility for the management of migrating game.
Protection of Waters and Flood Control
Wetlands are areas that are covered by water for at least most of the year and where vegetation and open water alternate. In wetlands, the flow speed of water is reduced and the sediment carried by water settles to the bottom of the marsh. At the same time, nutrients that are bound to the sediment are removed from the cycle. The wetland’s vegetation uses some soluble phosphorus for growth directly from the water and from the sediment through their roots, thus reducing the total phosphorus content of the water leaving the wetland. The wetland’s vegetation and microorganisms bind nitrogen and release it back into the atmosphere.Wetland working site.
Wetlands generally balance out the peak flows that take place in autumn and spring and, as a result, the water surface of the wetland begins to rise as the flow speed is reduced. The importance of wetlands both for flood control and water protection is largely based on their size in relation to the drainage basin and the inflow from it. If the wetland is too small in area in relation to the flow going through it, the flow speed will be too great and consequently the retention period will be too short. When water flows too quickly through the wetland, the sediment doesn’t get a chance to settle to the bottom of the pool and the amount of nutrients used by the plants has no significant effect on the total quantity of nutrients. With right sizing, however, both water protection and flood control benefits can be drawn from the wetland for the water bodies below it. In ecological flood control, it is primarily a matter of retaining the water in the drainage basin.
An Example of the Importance of Wetlands for Flood Control
The Vähä-Komu wetland deals with the water of a 2,200 hectare drainage basin with forest ditches especially in times of flood when the nutrient and sediment loads are at their highest. The wetland is 20 hectares in size, which is about 0.9 per cent of the drainage basin
area, and thus its relative size is sufficient for the protection of waters and to balance sudden flood peaks, with the rising water in the wetland acting as a temporary buffer. When the water level rises by 20 centimetres in an area of 20 hectares after thundery rain, this translates as 40,000 cubic metres of water. The filling and emptying of the storage basin balance the flow better than a corresponding rise of water surface in a narrow streambed.
The smaller the drainage basin and the larger the wetland, the more effectively the wetland reduces fleeting flood peaks and acts as a solution for water protection at the same time. The wetlands in Härmälä and Vuorela in Southwest Finland are excellent examples of headwater region wetlands whose size in relation to the drainage basin is great. A wetland of a few hundred square metres is sufficient to handle the runoff waters from a few dozen hectares. In the protection of waters, it is important to look close as well as far.
Landscape and Landscape Structure
The sight of water in a rural landscape is pleasing to the eye – who wouldn’t want to see the glimmer of water from their window? Wetlands bring variety to an otherwise monotonous landscape. Often wetlands established or restored in the middle of fields, or under cliffs in the shade of the forest have great scenic value. Wetlands in the middle of fields, or in a marshy hollow in the forest, bring life to the landscape also in the form of water birds that circle above them.
A network of wetlands offers water birds the brood-rearing habitats they need. A network of several wetland spots on just one field or in a farm’s woodland will improve the habitat for waterfowl and the local yield of nestlings more than a single site. Both in villages and wider regions, the system of wetlands and nutrient-rich lakes will determine the future and size of waterfowl populations, as well as whether the populations are robust enough for hunting. A network of high-quality habitats will determine the welfare and abundance of game populations.
Game populations are considerably larger in a landscape with enough places to find shelter and food. In an agricultural landscape, the key factors for species’ habitability and rural biodiversity are wetlands, strips of grass by streambeds, environmental fallows, functional crop rotation and wintertime plant cover. The key factors in forests are a controlled lack of management – i.e. sparing the undergrowth and shrubs that provide shelter – plus mixed forest stands and the management of ecotones and forests areas with bilberries, in addition to establishing wetlands.
For the success of many water birds and waders, the land use of the agricultural areas surrounding the wetland is equally as important as the good condition of the wetland. For example, the Pintail, Shoveler, Curlew and Lapwing nest in the fields surrounding a bird lake or a wetland located in the middle of a clearing. A large proportion of the nests and broods get destroyed during the springtime sowing and related work, or when the first grass crop is harvested. The destruction of nests can be avoided by favouring environmental fallow meadows, or grains and oil plants that are sown in the autumn in fields surrounding the wetland.