Lakeshore and wetland habitat destruction
Human activity is especially dangerous to Great Blue Herons. They do not acclimatize well, and when humans are within roughly 200 meters of their nests they may abandon it along with their eggs1. This contributes to the decline in heron populations, as these eggs will not survive to hatching or adulthood without parental care. Furthermore, Great Blue Herons are sensitive to human structures. They will not form nesting colonies around certain disturbances. The most distressing seems to be building structures, including cottages, followed by secondary roads and finally unimproved roads6. Species richness in Ontario wetlands is reduced when roads are within 1km of the wetland, but this richness will increase with more forest cover, which provides a larger habitat21. From this we learn that these birds are better able to survive when we minimize our disturbance of their habitats by maximizing our distance from the wetland. Ultimately, this increases the area of land for feeding and nesting, which will increase their chances of survival and their reproductive performance22. Unfortunately, we see the opposite pattern occurring. The increased development of areas in the South-eastern Ontario region is decreasing the habitat of the Great Blue Heron and limiting the space they have to colonize. Though this great bird does have a wide distribution throughout Ontario, breeding is mostly confined to the southern part of the province1. Development causes the wetlands in this part of the province to become fragmented into smaller “islands” within developing urban and agricultural land use19. This fragmentation reduces the amount of continuous wetland habitat; however, it is important that we try to conserve all areas of the wetlands that are still intact. Both large and small wetlands provide habitat for many species, such as the Great Blue Heron, that will still rely on these areas no matter their size19.
 |
| Source: http://www.peacham.com/travel/images/Heron1024.jpg |
Development near a lakeshore can have a large impact on bird species for several reasons. Some birds actually prefer the disturbed habitats surrounding houses and cottages, but others cannot adapt to it. Ground-nesting birds do not seem to be able to survive near humans. This could partly be due to the increased number of cats and raccoons associated with cottages, both of which are predators to birds. This, combined with ground disturbances such as lawn mowing and landscaping, make developed lakeshores an unfriendly habitat for many bird species7. Remember that if trees are not available, a Great Blue Heron will nest on the ground. This may become impossible near cottages and other structures.
Another trend observed on developed lakes is an increase in seed eating birds and a decrease in insect eating birds. This is problematic because without the birds to keep them in check, insect populations grow and can actually cause severe damage to the forest and surrounding areas. Furthermore, seed eating birds are not usually seen in such large numbers on forested lakeshores7. Changes to a habitat like this can have radiating effects on other species.
One big problem in shoreline habitats is changes in sedimentation. These have been directly observed in the Kingston and Southeast Ontario region, and are partially due to urbanization and cottage building. It is caused by run-off from construction sites and other human activities8. This can affect many organisms in an ecosystem. Algae communities change in relation to the type and amount of sedimentation in shallow waters. Visibility and water clarity can also be affected by sedimentation, which is a problem for animals who fish for their food, including the Great Blue Heron. Fish communities will change in relation to sedimentation, and some may not be able to breed properly8. Not only is this an obvious problem for the fish, but also harms the species that depend on them for food.
Another problem faced by lake-dwelling and lake-dependent species is water warming. This is caused by a variety of factors, but one of the major ones is deforestation. Changes in water temperatures cause different species to flourish, including the parasitic sea lamprey. This species attaches to fish with hook-like teeth and seriously harms them. Many warm water species have now been able to colonize lakes, at the expense of other species. Some scientists consider fish species to be unstable because of these factors8. A change in fish communities greatly affects fish eating birds like the Great Blue Heron, who so heavily rely on it as a food source.
 |
| Source: http://k43.pbase.com/o6/66/717166/1/70836435.Fv3J9vku.1DN_9909NIC1m.jpg |
How you can help
One of the most important ways to protect the Great Blue Heron is to not approach its nests. Even though the birds are beautiful, coming near a heron nest may lead to the adults abandoning their eggs. If you want a close look at a Great Blue Heron nest, use binoculars or other means of getting a closer look. That way, you can enjoy the spectacular view whenever you want, and the Great Blue Heron will still be there the next day.
There are many ways to reduce the changes seen in bird and fish populations near shorelines. When land is developed, there is a threshold of cottages that birds seem to be able to tolerate. Building fewer than 4 structures per kilometre of lakeshore habitat does not seem to cause distress to Great Blue Heron communities6. By spacing cottages out more, you will also decrease the chance of disturbing nesting sites of sensitive animals, including the Great Blue Heron. By giving a wider parameter around cottages, species that are sensitive to human activity are less likely to be affected by development. This building strategy is also beneficial to you, as there is less chance of noise and disturbance from the neighbours!
For cottages that have already been built, there are many ways to reduce your impact on bird species and promote species diversity. Ground disturbances such as lawn mowing can be reduced to encourage ground nesting birds. Steps should be taken to reduce the presence of raccoons, such as keeping garbage inside and minimizing trash thrown outside. Cats and other pets should also be kept inside as much as possible to reduce the dangers of nest predation7. If you have undeveloped cottage roads, think twice before paving them. Many animal species will not build their nests near secondary roads, but are less disturbed by undeveloped roads6. By taking these simple steps, crucial lakeshore habitats can once again be safe for the birds and wildlife that depend on them.
When building or doing construction on your home or cottage, be aware of the effects of run-off that can cause sedimentation. Avoid polluting the lake with substances such as wood chips or other junk that may affect shorelines, including water clarity. As much as possible, try to minimize dust and building materials from getting into the water. Although you may want open space around your cottage, think about leaving as many trees as you can standing8. Not only will this help to decrease water warming, but trees also provide an important habitat for many species. Leaving trees will also increase the chance that you will have a Great Blue Heron nest in your backyard, something you don’t want to miss!
 |
| Source: http://www.cottagesontheweb.com/324/Cottage%20from%20Lake%201.jpg |
To find out more about keeping our lakes and shorelines healthy, check out these websites:
