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 Biodiversity
variables
The TEMS directory
contains seven core variables related to the biodiversity of habitats
and species, these are:
Colonization of
habitat by invasive species
Invasive species are a major threat to biodiversity and often have important
socio-economic effects. The assessment of areas colonized by invasive
species (as percentage of the sites' habitat as a whole) can give an idea
of their impact on ecosystems.
variable
sheet
Habitat conversion
Habitat conversion means the change of land quality, for example through
land transformation or intensification of uses. Common reasons for habitat
conversion are among others deforestation, suburbanization, desertification
and agricultural intensification. The continued conversion of habitats
is a major contributor to the loss of biodiversity.
variable
sheet
Habitat fragmentation
Habitat fragmentation means the breaking up of a habitat, ecosystem, or
land-use type into smaller parcels. This may affect species richness as
well as important ecosystem functions. Monitoring of habitat fragmentation
and studies on the relation between species richness and habitat patterns
can contribute to the conservation of favourable habitat conditions.
variable
sheet
Indicator species
Measuring indicator species are useful because they can provide signs
of environmental problems such as air and water pollution, soil contamination,
climate change or habitat fragmentation. They can also provide information
on the integrated effect of a variety of environmental stresses and their
accumulative effects on the health of an organism, population, community
and/or ecosystem
variable
sheet
Pollinator species
Pollinator species play a crucial role in flowering plant reproduction
and in the production of fruits and vegetables. Since the interactions
between plants and their pollinators are essential to the healthy functioning
of wild and agricultural communities, the growing decline of pollinator
species presents a serious threat to biodiversity, the functioning of
the world's ecosystems and food production.
variable
sheet
Species Richness
One of the first steps in assessing biodiversity and the loss of biodiversity
at the site level can be the monitoring of the total number of species.
It is important to regularly collect inventories of different taxonomic
groups and also provide information on the number of species which are:
indigenous/exotic; endemic (from the indigenous); invasive (from the exotic);
migratory; and pollinators (see also pollinator species).
variable
sheet
Threatened Species
The variable provides a measure for the maintenance or, conversely, the
loss of species richness and diversity at the site level. The assessment
is carried out by evaluating the total number of threatened species; the
percentage of threatened species from the total number of known species;
and the percentage of endemic threatened species from the total number
of endemic species.
variable
sheet
Other TEMS variables
and socio-economic data that are relevant to Biodiversity
Directly linked to biodiversity:
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Variables
Biomass above ground
Fertilizer use
Land cover
Land use
Lifestock density
Soil annual loss from erosion
Soil macrofauna
Soil microfauna
Soil microflora
Vegetation cover and height class
Vegetation structure
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Socio-economic
data
Arable land
Conventions ratified
Forest deforestation
Forest plantation
Forest total area
Land area protected
Pesticide use
Population density
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Relevant to ecosystem quality:
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Variables
Evapotranspiration
Ground water depth
Leaf area index
Phenology
Soil bulk density
Soil erosion from gullying
Soil moisture storage capacity
Soil organic carbon
Soil pH
Soil rooting depth
Soil total carbon
Water biological oxygen demand
Water chlorophyll concentration
Water pH
Water sediment load
Water turbidity
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Socio-economic
data
Agriculture production index
Population growth rate
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Accurately measuring
biodiversity is a difficult task even at the site level. The large number
of methods and indicators that can be used also make inter-comparison
between sites very difficult.
This issue is being
addressed by the Convention
on Biological Diversity (CBD) which is developing a core set of indicators
(document contains a list of global indicator initiatives).
Many institutes and
organizations are involved in the development of standard methods to be
used in ecological studies. For example the European Centre for Nature
Conservation (ECNC) has recently released a publication on the "Biodiversity
indicators and monitoring - Moving towards implementation". The
publication provides the current status of biodiversity indicators and
monitoring at the various geographical levels and reviews the how effective
they are proven for the different biodiversity policies around the world.
Please also refer
to the literature section
for examples on the numerous publications that have been written on the
subject.
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