Physical habitat is always important, whether you are performing a bug or a fish collection. Things such as substrate, stream width and depth, flow of the water, and canopy cover are all important factors when it comes to assessing the habitat.
When doing a bug collection, we always look at the type of habitat observed. Is it a riffle? Or maybe there is no riffle, but there is some vegetation? Is there woody debris present? Most of the time, our bugs are collected in a rocky riffle, for several different reasons. One main reason rocky riffles are important is that they always have the most diverse and abundant bugs because this is where the most oxygen is. We always mark down what the riffle is made up of; silt and clay, sand, gravel, cobble, boulders, bedrock, or hard pan clay. These different substrate types can sometimes house different bugs. We also record the roughness of the riffle, the velocity, and any algae (filamentous or non-filamentous) or aquatic moss we see.
Performing a fish habitat assessment is a little more in depth. We still record the substrate, width and depth, flow, and canopy, but we also look at other aspects of the creek as well. Things like woody debris, animal paths, the presence of cows, and bank width and erosion are all added factors that we need to assess. Any cover for fish is also noted; things like logs in the water, undercut banks, or rock ledges are good hiding places for all kinds of fish. We do this for 400 meters (either upstream or downstream) of a site, stopping every 20 meters. Each of these 20 meters is called a transect, and this is the habitat area that we are assessing.
When doing a bug collection, we always look at the type of habitat observed. Is it a riffle? Or maybe there is no riffle, but there is some vegetation? Is there woody debris present? Most of the time, our bugs are collected in a rocky riffle, for several different reasons. One main reason rocky riffles are important is that they always have the most diverse and abundant bugs because this is where the most oxygen is. We always mark down what the riffle is made up of; silt and clay, sand, gravel, cobble, boulders, bedrock, or hard pan clay. These different substrate types can sometimes house different bugs. We also record the roughness of the riffle, the velocity, and any algae (filamentous or non-filamentous) or aquatic moss we see.
Performing a fish habitat assessment is a little more in depth. We still record the substrate, width and depth, flow, and canopy, but we also look at other aspects of the creek as well. Things like woody debris, animal paths, the presence of cows, and bank width and erosion are all added factors that we need to assess. Any cover for fish is also noted; things like logs in the water, undercut banks, or rock ledges are good hiding places for all kinds of fish. We do this for 400 meters (either upstream or downstream) of a site, stopping every 20 meters. Each of these 20 meters is called a transect, and this is the habitat area that we are assessing.