Biodiversity and Rainforest Structure
Do yourself a favor today and learn something about the big wet green and blue ball that we call Planet Earth.
What is biodiversity?
Biodiversity is a type of nested hierarchy where there is genetic diversity within a species, species diversity within an ecosystem, and ecosystem diversity within a region.
What is a species?
Morphological species have similarities of visible characteristics, which are easy to measure and most useful in practice, however they are not necessarily the most biologically relevant.
A biological species is testable in theory, and must have reproductive isolation. For example, a hybrid animal is not necessarily fertile, and cannot be considered its own species.
An evolutionary species is more complicated and has evolutionary relationships.
A look at the temporal/time scales of a species:
Evolution is the theory that a species alters over time to form new species.
Speciation is the formation of new species alongside the original species (see: Darwin’s finches).
Extinction is when a species is unable to reproduce successfully and die out.
Species are not necessarily, if ever, distributed evenly over earth. In general, there are more species to be found near the equator and tropical/Amazon area, and less to be found at the poles.
This can be explained through the energy hypothesis – where in areas of higher temperature, rain, and sun, more photosynthesis happens, and therefore higher rates of growth. There are other factors too – climate stability, so less need to adapt to changing seasons, and altitude, for example.
Species richness is a measure of the number of species.
Species evenness is a measure of how equal the abundances of different species are.
This calls for the measuring of organisms in the field. There is the Simpson index,
where n is the number of individuals of a species and N is the total number of all species.
Why measure it?
The data is not meaningless. We can determine the value of an area and identify any conservation priorities.
What are biodiversity hotspots?
Hotspots are areas with high biodiversity and many endemic (specific to one region) species. For example, the Jewel Scarab Beetle is endemic to the Cusuco Rainforest. Often, these hotspots are rainforests because of the biodiversity to be found in those regions.
These hotspots can be determined by measuring the number of endemic vascular plant species, vascular meaning containing xylem and phloem.
That being said, the data is not perfect either. It doesn’t take animals and ecosystem services, such as pollinators and water sources into account. And there are many endemic amphibians that contribute to biodiversity as well.
What is a rainforest?
A rainforest has high rainfall of 68-78 inches annually. They are globally important as biodiversity hotspots, sources of timber and medicinal plants, and carbon stores. Storing carbon in the rainforest reduces CO2 and keeps the climate and atmosphere in balance.
Where do you find the trees?
At the bottom is the floor herb layer, then the understory, the canopy, and the emergent layer.
How and why do we measure these trees?
Four measurements: The overall height, the height to the base of the crown, the depth of the crown, and the width of the tree.
The carbon that is stored in the trees can be measured by a clinometer.
To get the diameter of the tree at breast height, or 1.3 meters, take the circumference using a measuring tape divided by π. Also get the volume, V=ghfm^3. To find the height, stand one tree height away at a 45° angle.
Measure the leaf litter – depth, soil density (using 1.5 kg of weight), and the depth of depression.
Make a note of whether the tree is living or dead and the type: broadleaf, pine, tree fern, palm, dwarf, etc.
In the understory, count the number of stems.
For the canopy, figure out the canopy scope (out of 25).
Why are rainforests important?
The plants to be found in many rainforests helped to create modern medicine. And there are even more to be discovered.
They also have high endemism, and many species are yet to be discovered.
Rainforests provide a natural habitat for many species and are a vital water source for human beings and animals and plants alike.
They regulate the Earth’s climate and act as a carbon store.
Rainforests are also simply one of the oldest and most complex land-based ecosystems on earth, and deserve to be preserved.
Hope you enjoyed today’s post! More to come, every day! ~Gloria