Measuring Biomass: Taiga

Here’s the biomass pyramid of a food chain located at the taiga. This was made the previous semester in our investigation of the taiga concerning many of their aspects.

Measuring Biomass

Before naming the different methods of measuring biomass, it is important to know what is biomass. Biomass or production is considered as the total weight of living organisms within a given area. This includes plants and animals. Biomass is usually expressed as g/ha, lbs/acre, or g/m².

Now, there are several methods for the measurement of biomass. Here are some of them.

• The most basic one is counting the specific number of organisms of the same species within a given area. However, this method can be inaccurate and difficult to accomplish.
• Some people use their perception to calculate biomass, especially on plants. A trained person could estimate the weight of a plant just by looking at it. The person may calculate the mass of certain plant, for example 5 grams. So, like in the example, when the specialized person looks at the same plant but more of them (such as two more), he or she could infer that the approximate biomass of that species in a given area is of 15 grams.

• Biomass could also be estimated by looking at the changes in time and the possible abiotic factors that could have interfered. Here’s an example of an analysis made during three years. Precipitation was measured and visual evidence was taken. In here, biomass could be estimated visually, since changes in biomass are clearly seen at the visual evidence.

• There’s also the direct or destructive method, which consists in cutting (in case of plants) a vegetation in a certain area and weighing its mass. Several samplings should be made in order to get accurate data. The grams per quadrat are converted to the corresponding measuremeny system.
• However, there are other methods that do not involve the direct experimentation with the species. This can be by taking scale digital images. Images are analyzed in the computer, calculations are made according to the information provided by the images (such as green pixels showing the biomass in the image) and models were made.

Evaluation of these methods

     Looking at each of these methods and analyzing them, I figured out that some have advantages and other ones disadvantages. Some of them such as estimating its mass, observing its changes, or counting them, may be a little inaccurate, but they are ways in which you aren’t harming species. Others, such as measuring its dry mass could be a little harmful since for example, in grass, the grass should be clipped off. It may be more accurate than others, but still it is a destructive method. Furthermore, there’s also the scanning of the species via digital photos, which measures digitally the species biomass. It’s a good method since it may be really accurate and it’s a non-destructive method. However, it may be a little expensive.

     So, looking and evaluating each of the methods, we can say that each one of them has their advantages and disadvantages. The thing is to revise each one of them and look at the one with the most advantages. In my opinion, I think that the best one is the one that uses scanned digital photos, since it’s really accurate and non-destructive. However, it may me expensive.

References

Tackenberg, Oliver. "A New Method for Non-destructive Measurement of Biomass, Growth Rates, Vertical Biomass Distribution and Dry Matter Content Based on Digital Image Analysis." Annals of botany. Oxford University Press, 12 March 2007. Web. 25 Aug 2010. <http://aob.oxfordjournals.org/cgi/content/full/mcm009v1>.

"Biomass Terminology ." University of idaho. College of natural resources, n.d. Web. 25 Aug 2010. <http://www.cnr.uidaho.edu/veg_measure/Modules/Lessons/Module%206/6_1_Biomass%20Terminology.htm>.

"Direct Measures of Biomass ." University of idaho. College of natural resources, n.d. Web. 25 Aug 2010. <http://www.cnr.uidaho.edu/veg_measure/Modules/Lessons/Module%206/6_3_Direct%20Methods.htm>.

"Estimating Biomass and Double Sampling ." University of idaho. College of natural resources, n.d. Web. 25 Aug 2010. <http://www.cnr.uidaho.edu/veg_measure/Modules/Lessons/Module%206/6_4_Estimates%20Double%20Sampling.htm>.

"Why Measuring Biomass or Production?." University of idaho. College of natural resources, n.d. Web. 25 Aug 2010. <http://www.cnr.uidaho.edu/veg_measure/Modules/Lessons/Module%206/6_2_Why%20Measure%20Biomass.htm>.

Measuring Biodiversity

It is important to take into account that when measuring biodiversity it is being tried to describe the relationship between individuals of varying subspecies within a zone. There are three most common ways of measuring biodiversity.

Species richness (S)

This is one of the most common ways. It Works by counting the subspecies diversity in a specific community. However, this method doesn’t indicate the proportion nor how the species are distributed or organized.

Simpson’s Index (D)

Simpson created this method in 1949, and it’s similar to the previous one. This one works by counting the subspecies (richness) and it also measures the proportion.

The first step to calculate the Index, is calculation Pi which is the abundance of a certain subspecies in a certain zone, divided by the total number of subspecies in the same zone.

Simpson's index: D

D = sum(Pi2)

This one calculates the probability of two randomly selected organisms in the zone, belong to the same species

Simpson’s Index of diversity: 1 – D

This one is the contrary of the previous one: the probability of two randomly selected organisms in the zone, do not belong to the same species.

Simpson’s reciprocal index: 1/D

The last one calculated the amount of equally common subspecies that will produce the observed Simpson’s index.

Like already said, Simpson’s index may be affected by the richness and the equitability of percent of each species present. When talking about the richness, D will decrease as the percentage of species is more equitable.

Shannon-Wiener Index (H)

The last one works with the number of individuals observed for each subspecies located in a sample plot.

This works similarly like the previous one. First, it is necessary to calculate Pi for each category of subspecies. Then, you need to multiply the logarithm of Pi base 10. Then the index is computed with a negative sum. Here is the formula:

H = -sum(Pilog[Pi]) 


Important fact: Knowing the Shannon-Wiener Index and species richness, it may be known the eveness. But, what is eveness? Eveness is the measure of how similar the abundances of different species are. When the evenness is one, it means that they have similar proportions. But when the abundance isn’t similar, the value tends to increase.

"Biodiversity Measures." Raytheon Employees Wildlife Habitat Committe. REWHC, 2000. Web. 18 Aug 2010. <http://www.rewhc.org/biomeasures.shtml>.

Classification of plants

Classifying living organisms is an important task. The most known method of classifying living things was created by Carolus Linnaeus. He introduced a hierarchy that classified living organisms from broadest to most specific. The hierarchy made by Carolus Linnaeus consists of several classifications: Kingdom, Phylum, Class, Order, Family, Genus, and Species. The following were ordered from the broadest classification, to the most specific classification. 

But there may be other classifications, probably not so known as the one of Linnaeus. The following chart shows one of the many classifications plants may have. This was found in a document/activity of Helen Saayman.

Saayman, Hellen. "To classify plants according to their characteristics." Connexions. The Connexions Project, 11 Mar 2010. Web. 11 Aug 2010. <http://cnx.org/content/m20135/latest/>.

Previous knowledge from the past semester

What is a system? A system is a set of components that function and interact in a predictable manner.

Ecosystems. There are several examples of ecosystems such as: Estuaries, swamps and marshes, tropical rain forest, temperate forest, savanna, agricultural land, shrubland, temperate grassland, lakes and streams, continental shelf, open ocean, tundra, desert scrub, and extreme desert.

Trophic levels. The term trophic level refers to the position it occupies a species in a food chain. An example of a trophic level may be:

Grass (as a producer) -- Grasshoppers (as primary consumer) -- Toads (as secondary consumers) -- Snakes (as tertiary consumers)

Taiga as an ecosystem. The taiga has a lot of different species. For example, canopy trees, which are producers, are eaten by primary consumers such as beavers. However, beavers are eaten by secondary consumers such as wolves. In here, we can see not only the different trophic levels, but the flow of energy via each individual. As well, we can see that in each consumption, some of the energy is lost as heat.