Learning about disturbances in ecology is interesting; fire
is considered a natural disturbance and can be very helpful in terms of new
growth and species richness in a ecosystem.
Some plants fire to establish, germinate or reproduce. An example of
this is. An example of a plant that needs fire to germinate is the jack pine.
Found in the eastern United States and Canada the jack pine has pine cones that
are so hard and so thick that they need fire to melt the natural “glue” the
make that keeps them shut. The pine cones can hang on to trees for rears
without opening until a fire comes around to melt the resin that holds them
together. The jack pine and other plants the release seeds after a fire have
adapted to this for multiple reasons. These reasons include a lack of
undergrowth that will compete with them while they are small. Also fire
introduces nutrients that plants need to survive into the soil. Although fire
can impact and ecosystem in many ways, positively or negatively depending on
the species, after a fire it always leaves an ecosystem with room for new
growth.
Without disturbances in an ecosystem we would have far less species richness because of this we count on things such as fire, wind, flooding, ect. for species to thrive. Although sometimes us as humans try to bring everything to a balance, what we really should be doing is letting nature take it course.
https://www.nps.gov/fire/wildland-fire/learning-center/fire-in-depth/different-ecosystems/jack-pine-greatlakes.cfm
Sam,
ReplyDeleteI thought you made an interesting statement when you said that fire introduces nutrients into the soil, so I did a little reading on it. The USFS Rocky Mountain Research Station put out a publication on the effect of fire on soil (http://forest.moscowfsl.wsu.edu/smp/solo/documents/GTRs/INT_280/DeBano_INT-280.php).
Basically, what they found is that while some nutrients are consumed and lost, others can be made available from the organic matter in soil much quicker than from decomposition processes.
This can result in nutrient losses. Nitrogen, Phosphorus, and Sulfur are sensitive to high temperatures and will volatilize very quickly, often reverting to biologically unavailable forms. Nitrogen is especially important here--it often reverts to N2, and since it's a limiting nutrient in many ecosystems, this can be a problem. However, biologically available N can also be translocated to lower soil layers in higher concentrations, so colonizing plants that can get to that source are benefited.
Interesting stuff!