The Species Richness Of Aquatic Macro Invertebrates Among Three Streams Types

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Figure 1. The species richness of aquatic macro-invertebrates among three stream types. The same number of species was found in the forest and urban streams. There was an insignificantly higher number of species found in the agriculture stream. Figure 2. The biotic index of the three types of streams was calculated by the sum of total tolerance values divided by the sum of total number of individuals. The forest stream had the lowest FBI value, followed by the urban stream and the agriculture stream. Figure 3. The relative frequency of the functional feeding groups of each stream type. The total number of individuals for each stream was 368, 1334, and 510 for the forest, agriculture, and urban streams, respectively. The major…show more content…
Therefore, there is a trend in the number of species found in each stream type based on the riparian habitat. As the amount of organic pollution increased, there should have been a decrease in the species richness of the streams. Species richness also has an effect on the processing of leaf material. Less species richness due to organic pollution forces the litter breakdown to be dependent on microbial activity rather than shredders (Masese et al. 2014). In addition, microbial breakdown of leaf litter is accelerated by the presence of nutrients, which is high in agricultural streams (Masese et al. 2014). Therefore, the species richness of the agricultural stream should have been low and leaf processing would be controlled by bacteria. Although the agricultural stream had the highest species richness, the relative frequency of shredders was very low compared to the other functional feeding groups shown in Figure 3. Likewise, due to the organic pollution present in urban streams, it would be expected to have a low species richness and thus any leaf material would be processed by microbes as well. Furthermore, the forest stream should have had the highest species richness, which would in turn impact leaf processing by having the shredders drive leaf litter breakdown rather than microbes. The Family Biotic Index describes the water quality of a stream by averaging the tolerance values of all the individuals that were sampled (Hilsenhoff 1988). Based on the equation,
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