Indicator Species

Aquatic ecosystems
Oyster: They fed on organic material and pollutants in the water. They filter the water, removing the particles.
Vertebrate and invertebrate species: Found in rivers and streams. Can determine the grange pollution to kept in check.
Lilies: rivers, lakes, ponds and swamps. They absorb oxygen and sunlight. Indicate abundance of nutrients, which leads to eutrophication.

Mayfly larvae: Native specie that are adapted to live in certain biome. When its number decreases it is a very clear sign that the pollution levels are increasing. They reappear downstream as the effects of the discharge are diluted. This help to indicate the level of pollution in water.
Sludge Worm. Common in lakes and rivers. All fresh water ecosystems. They fed on the sediments and bacteria, hence a great population on them might indicate great pollution in the body water and oxygen-poor water. They indicate stagnant water unfit to drink.
Soil Indicator species
The plants that are found in certain soil might indicate the presence or absence of a specific substance.
Besides plants, there are many other indicators.
Birds eggs can be analyze to find out pesticide sin the soil.
Invertebrates:. Indicator species to identify the use of foreign soils, insecticides, pesticides, and other pollutants.
In Canada there are plans to use soil-living arthropods in order to quantify the pollution in the forests.
A good way to measure the healthiness of an ecosystem and to determine the presence of pollution is biodiversity. High biodiversity indicates a strong and healthy environment.

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Direct and Indirect Measurements

Direct sampling

• In situ. Actually, in the studied place.

Reliable and the best option because of the exact results gases
It is difficult to carry all of the instruments

• Ex situ. Off from the place where sample is established

Use of more methods and instruments, flexible
You cannot experiment instantly and so the sample could suffer some changes.
Shipping and handling is necessary.
When measuring pollution, direct measurements could be use to measure the concentration of:

• gases
• particulate matter
• pH
• dissolved oxygen
• biomass content
• salts
• conductivity
• turbidly

Most of the measurements are giving in units per area, or per
Indirect sample
These measurements are the ones where we measure one factor in order to study or get conclusions for other factor. They don’t really tell you the concentration, you need to interpret them.
Examples of it are

• Indicator species,  They define an specific area or a specific biome
• Biodiversity indexes
• Chromatography
• Spectroscopy

Against the idealism of carrying capacity

A population model assumes that the use of resources is equal to all of the individuals. The think here is that we are talking about “individuals” not hard numbers. They have different needs and life conditions. That’s why we cannot take the entire population of the world as in uniform conditions in order to establish the carrying capacity (K)
The individual/population resource use is a dynamic principle. We also must we aware that resources vary with time and space. Some of this variations are given by:

• MEDCs and LEDCs
• Urban vs. rural
• Young communities vs. older communities

However we need to manage carrying capacity to our advantage.
It might be trough pollution control
POLLUTION MANAGEMET
Natural income –> Human activity –> wastes –>  pollution
Pollution:the addition of a substance of agent to the environment by human activity at a rate grater that that at which it can be rendered harmless by the environment.
Major sources of pollution

• Combustion
• Domestic waste
• Industrial waste
• Agricultural waste

Pollution by noise, by heat.
Sources:

• Point source
• Non-point source

Detection and monitoring

• Directly. measure with a particular variable to refer an specific pollution factor. (CO2 presence in the atmosphere)
• Indirectly. Impact. uses a variable that depends on a specific factor. (e.g. acid rain: a wide range of possibilities to measure the impact; salinity on the atmosphere)

Pollution indicators

• Biological Oxygen Demand (BOD): amount of dissolved oxygen required to break down the organic material in a water volume through anaerobic or aerobic activity
• Indicator species (biotic index 1-10) through invertebrates

Three-level model of pollution management.
replace, regulate and restore
Waste management

Sustainable Yield in Deserts

Sustainability a wide spread term in the last decades. Economists, politicians, scientists and  businessmen are using it for everything. It is really a fashion nowadays. We must understand its real value and its real importance. A sustainable development is needed if we want to maintain the equilibrium of the world, respecting its carrying capacity. 
Sustainable yield is the the natural income that can be exploited each year without getting rid of the resources. Sustainable yield is different from one ecosystem to another. We’ll work with sustainable yield in deserts.
Specifications.
We must considered that resources in desert biomes are very scarce. The levels of precipitation are less than 15 cm a year. The diversity of desert’s flora is relatively low compared to other biomes. Contrary to the common belief the actual fauna of deserts is very rich and its concentrated in certain areas. The resources of deserts around the world differ from one and other. We can find oil and other fossil fuels in some deserts, minerals, and species richness.
In order to measure, and thus manage sustainable yield, we must establish space and time parameters. This will help us to know how much we have and how much we can use.
Useful indicators had been developed in order to maintain track of the advances in sustainable development. Some examples of this indicators can be found here, the Finland's sustainable development indicators:

• Human Development Index
• Greenhouse gas emissions
• Total energy consumption
• Use of renewable energy sources
• Energy and natural resource consumption in relation to economic growth
• Environmental loading in ration to economic growth

It is important to notice that not just because we are respecting the maximum sustainable yield (MSY) of a certain system, the resources will be endless. There are a lot of variations and factors that affect a system. A pretty good example of this is the chaotic situation of West Coast groundfish fishery in the United States, explained deeply here.
This is another thing in which indicators come handy and it’s the point where the management enters into the picture.
Links.
http://www.csgc.ucsd.edu/NEWSROOM/NEWSRELEASES/Carmel_Finley.html
http://www.ymparisto.fi/download.asp?contentid=92350&lan=en

The measuring Roll

The measurements information is used to value the state of things (good or wrong) and then act towards control the variables.

The methods for measuring biomass vary between ecosystems, biomes and type of organism.

It is important in the vegetation measurement, representing an indicator of productivity and of ecological and management processes in the vegetation.

Vegetation biomass measuring tell us what plant dominates a land by controlling the nutrients and water resources. Estimates of biomass and residual biomass also strongly influence the hydrologic properties of the site including infiltration, runoff, and erosion. Biomass of both grasses and woody plants constitute potential fuels that can be measured to assess the risk of wildfire.

Biomass can be directly measured with little training, although, it is time consuming.

*http://www.global-greenhouse-warming.com/measuring-biomass.html

The above MODIS Enhanced Vegetation Index (EVI) map above shows the density of plant growth over the entire globe. Very low values of EVI (white and brown areas) correspond to barren areas of rock, sand, or snow. Moderate values (light greens) represent shrub and grassland, while high values indicate temperate and tropical rainforests (dark greens). The MODIS EVI gives scientists a new tool for monitoring major fluctuations in vegetation and understanding how they affect, and are affected by, regional climate trends.

The biomass of a trophic level is likely to be proportional to the number of organisms and the energy found in each level. This could be graphically shown by the use of the ecological pyramid, which are graphical representations of the trophic structure of ecosystems:

*http://scienceaid.co.uk/biology/ecology/food.html

References.

http://www.cnr.uidaho.edu/veg_measure/Modules/Lessons/Module%206/6_2_Why%20Measure%20Biomass.htm