Relative Density Of Species

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Introduction Distribution of species is an important factor in a community. Depending on the biome, specific factors could have an effect on which species are found in certain areas; for instance, the woody plant distribution of species in a temperate deciduous forest can be affected by a variety of parameters. Temperate deciduous forests themselves are affected greatly by global factors, like climate change, and human agriculture (Reich et al 2002); the woody plants that populate the majority of them are distributed based on things like soil moisture, soil nutrients, soil pH, flooding patterns, elevation, and light (Hosner 1958, Bell 1980, Menges 1983). These factors play into how the species interact and compete with one another, and how …show more content…
Relative density (RD) was equal to N/S x 100, where N was the number of individuals of a species found in a sample, and S was the sum of all N. RD for each species of tree, sapling or shrub, and seedling shows what percentage of the total density that species accounts for. Relative frequency (RF) was equal to F/G x 100, where F was frequency and G was the sum of all F; it shows the how often each species of tree, sapling or shrub, and seedling occurred out of the total occurrences of all species. To determine how much area each species accounted for in the site, basal area was calculated by πd2/4, where d was the measured DBH. From here, Relative basal area (RBA) was determined for trees by K/L x 100, where K was the total basal area for a species and L was the sum of all basal areas of all species. Using RD, RF, and RBA, importance index (II) for each species of tree was found by (RD + RF + RBA)/3. For saplings and shrubs and seedlings, RBA was not calculated, so II was found by (RD + RF)/2. The II takes the number, distribution, and, in the case of trees, size, of a species and displays how significant their role is the community they belong …show more content…
The upland had much lower soil moisture than the lowland did, and although less diversity of species appeared in all three categories for the lowland, more plants in total were observed in the lowland. This has been observed in other studies as well, like in two studies by Bell (1974 and 1980). Lowland species are adept or used to flooding disturbances; therefore, there is less variation in the species found here because, according to the principle of allocation, an organism must choose where to spend its energy. For more species of woody plants found in a temperate deciduous forest, this energy is spent extracting moisture from maybe a less moist soil or reaching towards the sun for light, if that means not having to develop the adaptation to flooding. Cowell (1993) found that upland forests relied on soil moisture, where lowland plants had learned the optimal time for growing and reproducing by embracing the flooding patterns. The floodplain area was closer to the Grand River, allowing the soils to have higher water holding capacity. Considering this, the woody plant species found in the lowland had adaptations that assisted them in surviving the annual floods and anaerobic soils. Plants that choose to adapt to this flooding spend more energy towards the adapting, meaning less energy would be spent towards other life functions like reproduction and photosynthesizing. Although some species adapted to this flooding, the

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