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En
vir
onment
Part Three: indicators
lEvEl Of MEAsurEMEnT: Outcome.
dEfiniTiOn: This indicator measures the total number of species found during surveys in a defined area.
The species chosen for measurement in this indicator will be project- and site-specific.
Species richness is the single most important component of species diversity. Despite the conclusions
of many ecologists that species richness by itself is inadequate as a measure of species diversity, many
programs use species richness as the only measure of species diversity. Species monitoring should
include data collection on the total number of selected species in a defined target area, taking into
account temporal changes.
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sPECiEs riCHnEss
disAGGrEGATE: Type of species.
PurPOsE: Changes in the numbers of species may serve as early warnings for factors that can also affect
human health. Species that are successfully maintaining their numbers are an ecological indicator of
ecosystem health. Land-use change, climate change, and human activities such as fishing or hunting
may affect the number of species in a region. Habitat conversion or fragmentation may lead to declines
in the total number of species in a region or in certain species in particular.
dATA sOurCEs: Transect survey.
TiME frAME: Every two or three years.
dATA COllECTiOn COnsidErATiOns: The best representative umbrella species are those that have
the largest area requirements and the most diverse habitat requirements. These are species that may
serve to protect many others with smaller ranges. A selection of species with different habitat re-
quirements should be chosen for monitoring including seed dispersers, seed predators, food chain
predators, and pollinators that affect local ecosystem structure, productivity, and resilience. It is impor-
tant not to choose species for monitoring that are relatively scarce and have large geographic ranges
because environmental changes affecting one habitat type or location are less likely to influence the
total number of these species.
# of different species identified in a target area
total target area
Calculation
x 100
Summary :
Despite the conclusions of many ecologists that species richness by itself is inadequate as a measure of species diversity, many programs use species richness as the only measure of species diversity. Species monitoring should include data collection on the total number of selected species in a defined target area, taking into account temporal changes.
Tags :
area,total,number,habitat,richness,indicator,affect,many,monitoring,target,data,diersity,changes