Macroinvertebrate Ecological Factors

Factors Affecting Macroinvertebrate Diversity and Occurrence There are ecological factors regulating the distribution of macroinvertebrates (Hussain, Q.A). Water current, temperature, substrate, drainage basin land use/land cover, vegetation, pH of water, drought, flood, food, shade and stream geomorphology. Water current shows difference among aquatic animals according to its characteristics, either flowing water or a still water (Hussein). According to Steinnman, anatomical features of aquatic animals are influenced from their habitat due to adaptation (Hussein). Temperature is also an important ecological factor. It affects their emergence patterns, growth rates, metabolism, reproduction, and body size. The benthic macroinvertebrates have

Species vary in their tolerance to temperature ranges, but few are able to tolerate temperatures beyond their upper tolerance limit (Coutant, 1962; Angelier, 2003). Characteristics of substrate (bed material) are an important factor as physical habitat in river ecosystem (Hussein). Numerous studies have been conducted to demonstrate the influence of substrate and other habitat types on the population dynamics of aquatic insects and other macroinvertebrates (e.g., Minshall, 1984), and have mostly focused on larger particle sizes (usually cobble and coarse gravel), which constitute the riffles and runs of flowing waters. It is where benthic macroinvertebrates move, rest, shelter, and feed. Bed sediments affect the hydraulic stresses that benthic fauna utilize and must tolerate. The River Continuum Concept (RCC) views that the physical and biological processes of a river are affected by the physical processes outside of a river that also

Scientists have long assumed that the physical structure and condition of stream and river channels have pervasive effects on biological communities and processes (Hynes, 1970; Allan, 1995). Channel geomorphology also establishes relationship between benthic communities in different ways. Spindler, Patrice conducted a study of associations of stream channel morphology and macroinvertebrates. Significant taxa differences between tributary streams and large rivers were identified, with the greatest taxa richness occurring in tributary streams and shifts in species to more tolerant taxa in the larger rivers. The macroinvertebrate community responds to substrate parameters such as particle size and embeddedness, which directly affect benthic habitat. These findings reveal that the macroinvertebrates are responding to sedimentation (Spindler). Riparian vegetation is an important component of the river. It is significant in contributing shade for the river against sunlight that resulted in maintaining the water temperature that is suitable for organisms’ survival. The roots of the riparian vegetation are also significant for it sips most of the nutrient pollutants dissolved in groundwater before reaching the river. If the riparian vegetation was disturbed, the nutrients coming from soil goes to the river, the water temperature increases, and there will be