There are two habitats associated with creeks:

• the aquatic habitat of the waterway itself and
• the land area along either side of the creek, which is often called the 'riparian' zone.

The Riparian Zone

Many creeks in the Hamilton area run through urban parks or farmlands, and the near-creek area does not develop naturally. It may be kept clear to allow for ploughing or for access to water by livestock and irrigation equipment. In order to appear tidy, creek margins in parks and golf courses are often maintained with short grass right to the water's edge or decorative non-native plants. In these types of landscapes, the use of fertilizer on lawns or crops has an impact on habitat and water quality.

Red Hill Creek. Photo by Walt Mann.

In the more natural parts of the Hamilton area the riparian zone often resembles a forested landscape, but near the water's edge the species of trees, shrubs, herbaceous plants and even animals often differ from the forest around them. These riparian zones are where animals that eat fish and aquatic insects come to feed. The soil that is near the creek edge is much wetter than the higher forest soils nearby. Plants that do well in normal forest soils often are not adapted to these wet conditions but there are species that are well suited to exactly this kind of habitat, like willows (Salix spp.) and some other water-tolerant shrub species. In very wet areas, where the water does not flow very quickly, wetlands often form along creek edges, forming an entirely different habitat between the creek and the forest. Typically these are marshes but some creeks also run through peatlands.

The Aquatic Zone

Creeks are intriguing habitats. If you have ever been mesmerized by watching salmon making their way upstream to spawn you will understand the appeal of these environments. The main characteristic of creeks, of course, is that they are flowing.

To live in this habitat requires adaptations to moving water. Fish must remain in near-constant motion, or seek more tranquil areas, to avoid being swept downstream.

The same is true for the other major inhabitants of creeks: invertebrates, who must find ways to cling to objects in the creek.

There are four kinds of zones in creeks. Riffles are shallow areas where piles of rocks and debris occur, making the water flow quickly over and through them. Pools are where the water flows more slowly through bends and side channels in the creek, or in the areas just downstream of riffles. In channels, water runs very quickly through areas that are straight and unblocked. Finally there is the near-shore area where flow is slower and there may be fallen logs and other debris.

Winter creek. Photo by Barry Cherriere.

The appearance of these zones may be dramatically different from season to season and not all creeks have all of these zones. One of the challenges for creatures living in creek habitats is the changeable environment, with the water getting deeper and swifter in the spring when there is snow melting and rain falling, and getting shallow and slow in the heat of the summer. Autumn also brings rains that make creeks run higher while in winter many creeks are full of ice and have very little flow at all.