The key difference between biodiversity and species richness is that biodiversity refers to the variety of life found in a specific place on earth or the total variety of life on earth while species richness refers to the number of different species represented in an ecological community, landscape or region biodiversity and species richness are two different terms in ecology. C ountless species of plants, animals, and microbes fill every crack and crevice on land and in the sea. In this ar ticle, we focus on the estimation and comparison of species richness based on sampling data from each of the focal assemblages. A diversity index is a quantitative measure that reflects the number of different species and how evenly the individuals are distributed among those species. The relationship between species diversityrichness and community stability is quite complex. However, it is common for conservation biologists to speak of species diversity even when they are actually referring to species richness. 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. Alpha diversity refers to the diversity within a particular area or ecosystem, and is usually expressed by the number of species i. The way i measure species diversity is based on s number of species and n say abundance and distribution of abundance among species. The study of species diversity, or at least species richness, gives ecologists insights into the stability of communities walker, 1988. In ecosystems where there are species to species direct and indirect dependencies, diversity loss impacts ecosystem stability.
The relationship between species diversity and ecosystem function in low and highdiversity tropical african forests kelvin sehhwi peh submitted in accordance with the requirements for the degree of doctor of philosophy the university of leeds school of geography july, 2009 the candidate confirms that the work submitted is hisher own and. Experiments processes that regulate patterns of species and. Species relationships in the community may be conceived in terms of a multidimensional. In some places and some groups, hundreds of species exist, whereas in others, very few have evolved. Species diversity is a measurement of species richness combined with evenness, meaning it takes into account not only how many species are present but also how evenly distributed the numbers of each species are. This high level of ant diversity, including many rare species, suggests that ant species lists for most parts of the world may be very incomplete. On the other hand, species diversity is a function of the number of species present i. Three levels of biodiversity are commonly discussed genetic, species and ecosystem diversity.
Biodiversity sampling and statistical analysis for. Difference between biodiversity and species richness. At the same time, rare species tend not to be as competitive as the common species. Species richness is the number of species present in a sample, ecological community, ecosystem, landscape, region, or any defined spatial unit. Pdf on jan 1, 2005, andrew j hamilton and others published species diversity or biodiversity. Difference between genetic diversity and species diversity. An increase in resources can cause species diversity in a community to decline because greater levels of resources tend to cause a few species to dominate. A a diversity index is a mathematical measure of species diversity in a given community. Species diversity and richness 4 is designed for professional ecologists and their students. Genetic diversity is all the different genes contained in all the living species, including individual plants, animals, fungi, and microorganisms. What is the difference between species diversity and. The importance of species diversity to the ecosystem. Chronosequence studies of natural forest stands indicate that, following canopy closure, vascular plant species diversity.
A keystone species is an organism that helps maintain species diversity within an ecosystem by keeping the numbers of other species in an ecosystem constant. In this video we look at aqas version of an index of species diversity. Intertidal zonation does species diversity decrease with. The study was conducted to measure bird species diversity at taunsa barrage wildlife sanctuary from 2009 to 2011. The evenness of the sample is obtained from the formula. Alpha, beta, and gamma diversity biology libretexts. The most abundant species in this zone are semibalanus cariosis with 1,760 individuals, and balanus glandula with 982 individuals.
This is the diversity of species between two habitats or regions. Species diversity, stand structure, and species distribution. The number of different species in a particular region is known as species richness. The smallest sample size may be 1 km and the largest may be the entire region or country. Species richness an index based on the number of species i. Strictly speaking, species diversity is the number of different species in a particular area species richness weighted by some measure of abundance such as number of individuals or biomass. For all disturbance intensities and habitat types riparian vs. Species density or the number of species per m 2 is most commonly used to measure species richness. Species diversity is a term used to define the different number of species in an area species richness and the distribution of these species in that ecosystem. Justifications for protecting species diversity or biodiversity.
They make the world go round, converting sunlight to energy that fuels the rest of life, cycling carbon and nitrogen between inorganic and organic forms, and modifying the landscape. Hundreds of studies spanning terrestrial, aquatic, and marine ecosystems show that highdiversity mixtures are approximately twice as productive as monocultures of the same species and that this difference increases through time. The objective of the study was to identify avian diversity and main threats to them in the sanctuary. Species diversity and species richness ecointelligent. Using either presenceabsence data or quantitative data, it offers a wide range of both tried and tested and exciting new techniques to handle and analyse the. The relationship between species diversity richness and community stability is quite complex.
Species diversity measures version 5, 23 january 2014 page. Species abundance or evenness describes relative abundance of species. Beta diversity shows the different between microbial communities from different environments. C the more species you have, the more diverse the area. This wottechnical report was produced in accordance with the quality manual of the statutory. Whittaker 1972 described three terms for measuring biodiversity over spatial scales. Species richness the number of species that live in a certain location. The topic is important for understanding the causes and processes of biodiversity, for assessing the effects of human disturbance on biodiversity, and. Experimental communities in the diversity experiment were exposed to the first disturbance on day 7 and to the. It influences adaptability and distribution of a species in diverse habitats. Some of the major differences between genetic diversity and species diversity are as follows.
Meanings of species diversity may include species richness, taxonomic or phylogenetic. Species richness and species diversity are two important measures in a particular region which produce clear inference about the biodiversity of that region. Species richness variety of species or the number of different species or genera, families, etc. The species richness of the mussel zone totals thirteen separate species with 4,270 individuals. The diversity of our biosphere ranges from macromolecules of a cell to different biomes. Difficult to define because definition consists of two distinct components. What is the formula for species diversity the index of diversity. 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. Main focus is on the difference in taxonomic abundance profiles from different samples. Tradeoffs between the displacement risk or displacement ability of a species and either disturbance risk or colonising ability were not apparent. By not allowing one species or another to become overly dominant, a keystone species maintains species diversity and ecosystem integrity. Species diversity is determined not only by the number of species within a biological communityi.
Species abundance is the number of individuals per species, and relative abundance. We examined the relationship between taxonomybased species diversity. It is related to number of genes and their alleles found in organisms. What is the difference between species richness and. In essence it measures the probability that two individuals randomly selected from an area will belong to the same species. Typically, the value of a diversity index increases when the number of types increases and the evenness increases. Simpsons index d is a measure of diversity, which takes into account both species richness, and an evenness of abundance among the species present. Ecosystem stability impacts population growth and decay and because of the asymmetry between gain and loss in systems go.
Species richness is the number of species found in a community or ecosystem. Species richness means the variability number of species within a region ec. Species richness, as measure of diversity, has been used by ecologists. The mean number of species, and 95% confidence interval, is 6. Nevertheless species diversity is a large part of the focus of biodiversity at the local and regional scale, and we will concentrate here on how to measure species diversity. Species richness is a term used to define the number of species in an area.
If students calculate species richness and allelic richness on their own in class. Species diversity is all the different species, as well as the differences within and. 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. It represents the species richness or number of species found in an ecological community, the abundance or number of individuals per species, and the distribution or evenness of species. Species diversity and stand structure are essential for forest biodiversity because trees provide the basic needs and habitat for other species. The variety of life forms of a particular area are referred to as biodiversity. Evenness we can compare the actual diversity value to the maximum possible diversity by using a measure called evenness. This video explains species diversity and demonstrates how to calculate species diversity between two communities. The relationship between species diversity and ecosystem.
We discuss what is meant by biodiversity, and calculate an example. Biogeographic region biogeographic region components of species diversity. Its merely a numerical characteristic of an ecosystem. The maximum diversity hmax of a sample is found when all species are equally abundant. Species diversity and functional diversity relationship. Species diversity is a major determinant of ecosystem productivity, stability, invasibility, and nutrient dynamics. Species diversity is the number of different species that are represented in a given community. The principles can be applied to any unit of ecological organization. Species diversity is a measurement of biological diversity to be found in a specific ecological community. Different authors have used different indices to measure species diversity and the whole subject. Difference between species richness and species diversity. B based on the species richness the number of species present and species abundance the number of individuals per species. However, species richness increases with sample size. View enhanced pdf access article on wiley online library html view download pdf for offline viewing.
Biogeographic region components of species diversity. Species diversity concepts describing communities species. Genetic diversity the genetic material of microorganisms, plants and animals contains information that. Main difference genetic diversity vs species diversity.
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