Answer questions 1 and 4 110Quadrat-Based EstimatesThe simplest description of a plant community in a habitat is alist of the species that are present. This qualitative assessment ofthe community has the limitation of not providing any informationabout the relative abundance of the species present. Quickestimates can be made using abundance scales, such as theWhat Size Quadrat?Quadrats are usually square, and cover 0.25 m² (0.5 m x 0.5 m) or 1 m², but they can be of any size or shape, even a single point. The quadratsused to sample plant communities are often 0.25 m². This size is ideal for low-growing vegetation, but quadrat size needs to be adjusted tohabitat type. The quadrat must be large enough to be representative of the community, but not so large as to take a very long time to use.A quadrat covering an area of 0.25 m² is suitable formost low growing plant communities, such as thisalpine meadow, fields, and grasslands.(a)How Many Quadrats?As well as deciding on a suitable quadrat size, the otherconsideration is how many quadrats to take (the samplesize). In species-poor or very homogeneous habitats, asmall number of quadrats will be sufficient. In species-richor heterogeneous habitats, more quadrats will be needed toensure that all species are represented adequately.(b)Determining the number of quadrats neededPlot the cumulative number of species recorded(on the y axis) against the number of quadratsalready taken (on the x axis).The point at which the curve levels off indicates.the suitable number of quadrats required..Larger quadrats (e.g. 1 m²) are needed forcommunities with shrubs and trees. Quadrats aslarge as 4 mx 4 m may be needed in woodlands..ACFOR scale described below. Estimates of percentage coverprovide similar information. These methods require the use ofquadrats. Quadrats are used extensively in plant ecology. Thisactivity outlines some of the common considerations when usingquadrats to sample plant communities.Fewer quadrats are needed in species-poor or veryuniform habitats, such as this bluebell woodland.Small quadrats (0.01 m² or 100 mm x 100 mm)are appropriate for lichens and mosses on rockfaces and tree trunks.Describing VegetationDensity (number of individuals per unit area) is a usefulmeasure of abundance for animal populations, but can beproblematic in plant communities where it can be difficultto determine where one plant ends and another begins.For this reason, plant abundance is often assessed usingpercentage cover. Here, the percentage of each quadratcovered by each species is recorded, either as a numericalvalue or using an abundance scale such as the ACFOR scale.The ACFORAbundance ScaleA Abundant (30% +)C = Common (20-29%)F = Frequent (10-19%)O Occasional (5-9%)R = Rare (1-4%)1. Describe one difference between the methods used to assess species abundance in plant and in animal communities:The ACFOR scale could beused to assess the abundanceof species in this wildflowermeadow. Abundance scales.are subjective, but it is notdifficult to determine whichabundance category eachspecies falls into.2. Identify the main consideration when determining appropriate quadrat size:3. Identify the main consideration when determining number of quadrats:4. Explain two main disadvantages of using the ACFOR abundance scale to record information about a plant community:

Question

Accepted Answer

Ans 1)Relative species abundance is calculated by dividing the number of species from one group by…