Species diversity, stand structure, and species distribution. Journal of wildlife management, plant species biology, endangered species research, mammalian species, international journal for parasitology. Have you ever wondered how many species live on earth. Species richness variety of species or the number of different species. Sum summation pi numbe of individuals of species itotal number of samples s number of species or species richness h max maximum diversity possible e evenesshh max. Data from pitfall trap grids should usually be treated as sample based occurrences, and analyzed with sample based rarefaction and diversity estimators. The mean shannon diversity of echinoderms in babanlagan, talisayan, misamis oriental was h. Statistics shannon wiener diversity index tutorialspoint. The number of a species within a given sample, community or area usually from a particular taxa, e. The effective number of species refers to the number of equally abundant species needed to obtain the same mean proportional species abundance as that observed in the dataset of interest where all species may not be equally abundant. Biodiversity and resilience of ecosystem functions wsl. The study of the spatial distribution of organisms, species and ecosystems, is the science of biogeography. Genetic diversity the genetic material of microorganisms, plants and animals contains information that.
A measure of the homogeneity of abun dances in a sample or a community. For example, models that describe the broadscale relationships between climate and woody plant richness have been developed by field et al. Sampling and estimation procedures for the vegetation diversity and structure indicator of the current field data collection methods, and specific issues related to collecting vegetation data on fia plots. Species density or the number of species per m 2 is most commonly used to measure species richness. Just count the species in your sample to calculate it. Twentyfour measures of species diversity, richness and equitability were compared using both real species abundance data bird censuses on a standard study plot and simple simulation tests.
Species diversity is all the differences within and between populations. The plant community data analysis section provides background information on plant community analysis for analysts who are. Colombia and kenya, for example, each have more than 1,000 breeding species of birds, whereas the forests of great britain and of eastern north america are home. Biodiversity is important because it clears out our water, changes out climate, and. For example, if the number of species is more important than the relative abundance of species in your study system, i would recommend species richness as a diversity index. It is the variation in the ecosystems found in a region or the variation in ecosystems over the whole planet. Species diversity is defined as the countable number of species and abundance of these species that are present in a particular region. A lake contains 934 brown trout, 733 smallmouth bass, 34 catfish, 2003 carp, 234 steelheads, and 32 northern.
An ecosystem can exist at any scale, for example, from the size of a small tide pool up to the size of the entire biosphere. An example how species diversity contributes to the reliability of an ecosystem. The maximum diversity hmax of a sample is found when all species are equally abundant. C the more species you have, the more diverse the area. The methods on offer range from the familiar, such as the calculation of various diversity indices and the fitting of common distributions, to more recentlydeveloped techniques such as total species complement estimators. Brachyhypopomus gauderio, new species, a new example of underestimated species diversity of electric fishes in the southern south america gymnotiformes. That is what makes our country one of the 12 mega diversity countries of the world. How can we measure species richness when we only have a sample of the communitys total richness. For example, maintaining genetic diversity for the resilience of ecosystem functions. Species diversity is defined as the number of species and amplitude of each species that live in a particular location or ecological community. Assessing methods for comparing species diversity from disparate. Biodiversity sampling and statistical analysis for.
Measuring biological diversity an exercise in community ecology. Our online biodiversity trivia quizzes can be adapted to suit your requirements for taking some of the top biodiversity quizzes. Develop a bootstrap analysis of how sample size affects species richness estimates. Alien species a species occurring in an area outside of its historically known natural range as a result of intentional or accidental dispersal by human activities also known as an exotic or introduced species. Species concepts originate in taxonomy, where the species is the basic rank of classi. Among other factors, the diversity of all living things depends on temperature, precipitation, altitude, soils, geography and the presence of other species. Determine how community composition affects species richness estimates. The summation of all the organisms of the same species or species group that live in a particular geographical area and have the capability of interbreeding. Species diversity takes into consideration species richness, which is the total number of different species in a community. Pdf concepts of species diversity by charlie laman unimas. Ecosystem diversity deals with the variations in ecosystems within a geographical location and its overall impact on human existence and the environment ecosystem diversity is a type of biodiversity. It also takes into account evenness, which is the variation of abundance in individuals per species in a.
In this lesson, you will learn about the importance. A general hypothesis of species diversity the american. Chapter 2 biodiversity, ecosystems and ecosystem services. We suggest that at the very least, authors should define. Species richness, as measure of diversity, has been used by ecologists. An example of species diversity would be the rainforest. Pdf the measurement of species diversity researchgate. For example, if there are five species in the sample, then maximum value is 5. Sampling and estimation procedures for the vegetation. The smallest sample size may be 1 km and the largest may be the entire region or country. In the example in table, the total number of species for the three ecosystems 14, which represent the gamma diversity.
Gamma diversity is a measure of the overall diversity for the different ecosystems within a region. The hypothesis assumes that most communities exist in a state of nonequilibrium where competitive equilibrium is prevented by periodic population reductions and. We may, for example, explore questions about the development of. A common measure of this variety, called species richness, is the count of species in an area.
Biological diversity or biodiversity is gen erally divided into three fundamental categories. However, species richness increases with sample size. So, some examples may include the presence of four or five different species of tree in a woodland. Species richness the number of species that live in a certain location. A comprehensive database of more than 22 biodiversity quizzes online, test your knowledge with biodiversity quiz questions.
Biodiversity and conservation although india h as only 2. Biodiversity acronyms areas countries marine terms definition biological diversity means the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are a part. A number of different species in a particular location. Simpsons diversity index apply simpsons reciprocal diversity index and outline its significance. Difficult to define because definition consists of two distinct components. The evenness of the sample is obtained from the formula. Sample size estimation types of diversity species abundance curves diversity indices the usefulness thereof sample size determination to. An ecosystem is a community plus the physical environment that it occupies at a given time. Species richness variety of species or the number of different species or genera, families, etc. Diversity index for mixed nuts species richness for deluxe mixed nuts diversity index for deluxe mixed nuts 3. Speciation all species on earth thought to share single common ancestor that is life arose once, ca. Species diversity list of high impact articles ppts.
However, this is not to say that such measures are mutually exclusive. Biodiversity is not evenly distributed, rather it varies greatly across the globe as well as within regions. The intuition behind this definition is that if all of 97 the types in the distribution occur with the same probability, then diversity 98 should simply be equal to the. Species richness an index based on the number of species i. Alpha, beta, and gamma diversity biology libretexts. Species diversity and richness 4 is designed for professional ecologists and their students.
Genetic diversity is all the different genes contained in all individual plants, animals, fungi, and microorganisms. Evenness we can compare the actual diversity value to the maximum possible diversity by using a measure called evenness. Species diversity is the number of different species that are represented in a given community a dataset. The main difference between species diversity and ecosystem diversity is that the species diversity is the variety of species in a particular region whereas the ecosystem diversity is the variety of ecosystems in a particular area species diversity and ecosystem diversity, along with genetic diversity, are the three levels of biodiversity on the earth. Measuring biological diversity an exercise in community. A new hypothesis, based on differences in the rates at which populations of competing species approach competitive equilibrium reduction or exclusion of some species, is proposed to explain patterns of species diversity. Species diversity and evenness species diversity was calculated for the seven transects using the shannon index of diversity margalef 1957 and species evenness pielou 1975. Nearly 45,000 species of plants and twice as many of animals have been recorded from india. Forest composition and tree species diversity have been recognized as primary. Calculate the diversity index of one or more of the plant collections in the greenhouse. This is because it is a home to many different species of organisms. Learn how to calculate shannon wiener diversity index with clear definition, formula and example.
Diversity and dispersion patterns of echinoderms in. However, lakes, marshes, and forest stands represent more typical examples of the areas that are compared in discussions of ecosystem diversity. Biodiversity biodiversityshort for biological diversity means the diversity of life in all its formsthe diversity. Define the total number of species recognized in this sample as species richness instruct students to count and record the number of individuals of each of the species something like 4 saguaros, 3 ocotillo, 2 palo verdes, 1 barrel cactus, 1 cholla, and 1 human. B based on the species richness the number of species present and species abundance the number of individuals per species. Statistics shannon wiener diversity index in the literature, the terms species richness and species diversity are sometimes used interchangeably. It occurs within a species as well as between species. Biodiversity, ecosystems and ecosystem services 7 biodiversity at a suitable scale, e. There are numerous reasons why species diversity is essential. The maximum number for a location is equal to the total number of species present. The name simpsons diversity index is often very loosely applied and all three related indices described above simpsons index, simpsons index of diversity and simpsons reciprocal index have been quoted under term, depending on authors. Biodiversity, also called biological diversity, the variety of life found in a place on earth or, often, the total variety of life on earth. Species diversity refers to the measure of diversity in an ecological community. Usually three levels of biodiversity are discussedgenetic, species, and ecosystem diversity.
960 567 905 1426 416 1391 999 1117 509 682 674 101 1623 1579 612 442 599 1166 1155 2 1604 749 326 813 513 538 435 726 1234 1409 252 43 1423 862 190 1210 1146