Wetland issuesRestoring a Balance
Despite our best efforts to preserve those areas bordering city limits that have been less affected by urban development, we must also examine existing urban wild life areas for models of what can exist in cities. We need to look at how they have managed to survive and evolve along with the city. Urban sites are "degraded" when compared to more distant pristine sites but they have value because they are urban. The fact that these urban wild lands survive and are accessible to such a large urban population certainly contributes to the mental and physical health of local residents.
In some areas where there is a substantial loss of habitat, restoration may be more important than protecting the small proportion of habitat that remains. Restoration may add to the number of or quality of wetland loss to urban growth. It is usually in degraded environments that we want to compensate for the loss or fragmentation of habitat by reconstructing natural habitats which either resemble what was once there or which reflect the reality of what might grow given the current conditions .
We must accept the challenge of releasing the naturalized landscape to pursue its own direction at its own speed. One cannot singularly judge a backyard as a success or failure. Even if the wetland does not meet our initial expectations, it will contribute to the community mosaic of habitats. The true challenge of community green plans will be to accept and tolerate the differences in habitats which represent different energies. Each habitat is unique and there will be no failures that time and adaptive wild life cannot heal.
Wetlands designed and built to function as water purifiers and hydrological storage areas will also support wild life populations. We should design to meet wild life values at the onset. Without diversity of design and the opportunity to incorporate successional gradients, community wetlands develop a homogeneity that does not reflect the uniqueness of each watershed. We have a role to play in ensuring that policy makers, wetland engineers and developers incorporate wild life habitats in the design of wetlands. This can often be done without additional cost. Ecosystem and habitat conservation can be compatible with economic development. However, we must include the true cost of the loss of self regulating and self renewing habitats. The loss of biodiversity and watershed functions have costs that must be borne by generations unborn.
It may be tempting to view ecosystem components or functions as units that can be improved upon; shuffled about the landscape; or created to replace what has been lost. It is better to strive for a healthy balance of species. Sometimes, while waiting for our mix of water and plants to develop into a functioning wetland, we try to organize the system to avoid duckweed, mosquitoes, or algae. We may remove the predaceous dragonfly larva because it eats our treasured tadpole. But we do not realize that it will transform into that treasured dragonfly that keeps our mosquitoes under control.
Even in our created habitats it may be best not to intervene. Natural succession from seeds left in the soil (seed banks) will provide a "local" character. We are often too quick to plant without waiting to experience what communities develop from natural regeneration. Although there may be a short term confusing mix of species, only those that can tolerate the local microclimate, soil and hydrological conditions can persist. Certainly in degraded environments, new plant assemblages and associations adapted to that particular site may develop where few other plants could survive. Who could have anticipated the rapid colonization, diversity and informal nature of the Leslie St. Spit landfill or the rapid development of habitats and animals that quickly move into this new habitat.
We sometimes assume that there are not enough naturally occurring seeds or parent plants to create a new wetland. This may only be partly true. Although these created habitats may not replace the original habitat it is possible to create conditions that encourage natural succession. For example, intense mowing cuts off fruits and flowers, reducing the survival of some species. If you mow less, these plants may have a better chance of surviving and reproducing. When we add together the "wild" spaces occupied by cemeteries, railway , hydro, and gas lines, golf courses, river valleys, waterfront corridors, road allowances, abandoned fields, large uncut grasslands occupied by industry and our frog friendly school yards and backyards, the value of urbanized refuges is enhanced.
In most cases our "tampering" with the existing balance of the wetland will only result in short term change and the natural tendency of the wetland system will be to return to the balance of the local conditions. Thus many small restoration attempts will fail to meet the expected returns and the energy applied to the wetland will be wasted. Wetlands created for wild life may require more intensive management until they reach some sort of balance with the nutrient budget of the wetland. Occasion ally wetlands, especially those formed due to interrupted drainage or trapped within developments or by roads, are affected by increased sedimentation or unreliable water supplies. Remedial action may be necessary to address the long term impacts o. Management will also be necessary if wetlands are constructed on non-wetland sites (ie. where the water table does not reach the surface) or if it is necessary to maintain some successional stage. The latter may be necessary for wetlands underrepresented in an area or which play an important function not addressed within the local watershed. There is a danger in trying to achieve "instant habitat" or habitat stereotypes complete with visually appealing or rare species at the expense of the community and its long term viability as a whole.
Wetlands more and more ARE the last remaining wild areas and harbour wild life communities which can live nowhere else. We must not accept restoration as a substitute for our existing wetland functions. Not only does remediation, restoration and creation cost a great deal and require a great deal of energy to set up and stabilize, but they cannot substitute for wetlands that have stabilized and functioned for thousands of years. These systems have developed their own dynamic balance which incorporates life and death, rising and falling water levels, and internal energy and nutrient budgets.
The extent to which we can convince planners and developers of the importance of leaving a matrix of functioning habitat, the better the habitat for humans and wild life. Habitat mosaics and remnants planned into the community will improve the recovery process. The variety of backyard habitats in different stages of restoration will provide conditions necessary for a diversity of organisms. We share a biological inheritance with all living things and ultimately will benefit mentally and physically from the health of wild life populations around us. The global village begins at our doorstep.
We all have responsibility for the health of our planet and none of us can ignore the contribution individual action in our own backyards and communities makes to the health of global ecosystems. We have power, and that power is best expressed and appreciated within the context of your community's green plan for human and environmental health. It is the purpose of this publication to empower you to act as an individual and as a community- within your bioregion and globally. We may even learn to value and tolerate that which is different and which we may not fully understand.