Tuesday, January 25, 2011

The effects of substrate particle size on insect distribution and leaf decomposition

Reice, Seth R. 1980.The Role of Substratum in Benthic Macroinvertebrate Microdistribution and Litter Decomposition in a Woodland Stream. Ecology 11: 580-590.

Reice studied the relationship substrate size had with both the rate of leaf decomposition and aquatic insect distribution. This was done by creating baskets with three different sizes of substrate, covering half with leaf packs, placing them in the same area of a stream to reduce velocity variations, and sampling from them every two weeks for two months.

Leaf decomposition was the same for all three substrate groups at first, but by the end of the two months the substrate composed of cobbles, the largest used, had the most remaining leaf material. All leaf packs, regardless of their substrate, had about the same amount of insects inside them, meaning this was not a factor for the difference in decomposition. Insect density was greater on the leaves than on any of the substrates, and the presence of a leaf pack generally increased the density in the substrate below it. Preference over substrate size varied greatly by species, but density was overall higher in the largest substrate.

A strong aspect of this study is the fact that Reice managed to avoid the interrelatedness of current velocity and substrate particle size by studying patches of artificial substrate. This allowed him to view substrate preference as independent of preference for current speed. This study was conducted only during two months in the winter, and probably should have been repeated during other seasons to see if water temperature had any impact on the results.

1 comment:

  1. Good points on continuing the study into other seasons. Was this study done in New Hampshire? If so, or similar, I would imagine temperature would be an important factor. Have you looked at the author's later work to see if continued?
    ABK

    ReplyDelete