Book SectionsTable of Contents
The Problem Puddle Power Frog-Friendly Backyard Why are we concerned about amphibians?
Wetlands - function/type Wetland issues
How to help amphibians
Community Green Plans
Ecological planning beyond the birdbath Before you start Urban Wetlands Marshes
Drainage ditches Stormwater retention ponds Ephemeral ponds River valleys
Swamps Wet meadows Beaver pond Management
Before you start
We should not underestimate the importance of appropriately constructed garden ponds. For example in a 1979 British study published in Biological Conservation, Trevor Bebee found that the common frog (Rana temporaria) bred in half of his study ponds. In the reverse of what we might expect, common newts in Britain have increased in urban areas while suffering a decline nationally. In countries with a long tradition of urban and industrial landuse, garden ponds may actually become THE major contributor to amphibian reproduction. In urban areas, hydro corridors were looked upon as destroyers of habitat. Now hydro corridors are all that is left of wild life habitat and often represents excellent opportunities to link pristine but isolated habitats. In many of our urban areas we are fortunate in having enough remnant habitats that garden ponds can be linked to rural landscapes. Wild life will arrive as your backyard habitat matures. Resist the temptation to move wild life from a habitat that has had time to find its own balance.
The most important aspects of restoration projects are an understanding of local hydrology, the development of linkages with adjacent habitats and the creation of diverse habitat types and ages. The recreation of a balanced wetland with a similar watershed function is rarely possible. There has been some criticism of wetland creation and restoration projects for their emphasis on creating marshes. We should recognize that even under natural conditions many wetlands tend to evolve into marshes. Wetlands rarely need "enhancement" by removing the conditions that have allowed one or two species to dominate the habitat.
Although we manage the recreated habitat, we often do not manage the final outcome. We need to provide a way in which natural succession can begin anew, creating a mosaic of successional stages. We are fortunate that marshland vegetation readily and quickly establishes itself on saturated soils. We just have to look along railway lines, roads or in gravel pits for evidence of many wetlands formed when water was retained. Unfortunately, this leads us to believe that we can create wetlands anywhere and that these created wetlands balance the loss of existing wetlands. It is important to preserve existing wetland remnants, especially high quality ones, while increasing wetland diversity through restoration and a succession of wetland species. Consult with local conservation authority offices, Naturalist Club or organizations such as The Federation of Ontario Naturalists and Ducks Unlimited about wetland creation programmes. Environment and Agriculture ministries also have wetland restoration programmes for farmers.
Wetlands are most often created by a disturbance of some sort that causes interrupted drainage and pooling. Disturbance creates, alters, destroys and again creates wetlands. This a difficult concept for many conservationists to grasp as we usually seek to stabilize environments. It is disturbance that interrupts the natural hydrology enough to impound water, kill the existing vegetation and to allow the wetland successional process to begin anew. That is why beaver are such active agents in wetland creation. As their food supply is reduced they raise the dam height causing a rise in water level. They can then reach trees further away from the existing shoreline. Water levels change under the water management scheme of the resident beavers. However, as the food supply runs out, beaver abandon these sights, and succession towards a meadow begins. Beaver will only return if pioneer succession tree species, such as poplar, are established.
Wetlands are transitional stages in the succession of a site. However, it is appropriate to manage water levels, to maintain the historical balance between terrestrial and wetland environments.
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