I plan to study the Balsam poplar tree in three different gradients near the Elk River. I noticed a change in frequency and age as we moved from the riparian ecosystem towards a forest ecosystem. There are three locations I plan to study,
- On the flood plains beside the river where there is seasonal disturbances from the flooding every spring. In this area there were a lot of small, young balsam poplar trees and seedlings.
- As you move away from the river, the balsam trees become larger/older and more different species of trees and shrubs become noticeable.
- The next gradient is the forest ecosystem which contains a more biodiverse mixture of trees and plant life. I thought there was less poplar trees, more of which were fallen down or dead. But more coniferous trees have taken.
this lead me to believe that balsam poplar trees are pioneer species in the succession of forest regrowth in areas of regular disturbances. underlying processes for this must be that they have rapid regrowth rates, seed dispersal, and they must impact the soil conditions making it more habitable for other species to grow. Are they primary successors and do they change the habitat for other species to thrive? or are they abundant because of their resilience to regular flooding conditions.
My hypothesis would be ,
Populous balsamifera act as primary successors in forest regrowth due to disturbances like flooding. Exhibiting faster growth rates, resilience to flooding, efficient colonization and soil development, thereby playing a significant role in initiating successional regrowth in forest ecosystems.
my prediction is that in places on the riverbed where there is disturbance, populous balsamifera will be abundant compared to other tree species. furthermore the properties of soil will begin to change as the trees become older due to increased organic matter and nutrient availability. this begins the process for other species that are slower to grow to begin to thrive.
potential response variable would be the amount of balsam poplar trees measured in density at specific disturbed areas where there is noticeable flooding. this can establish the degree of dominence of the trees in early stages of regeneration and growth ability. this would be a continuous variable.
an explanatory variable would be measuring the organic matter at different areas towards the forest. representing the amount of soil and nutrient availability for other plant life. this is a continuous variable.
Hi, I think this is a great gradient and focusing on poplar specifically could be a good study. I think there is a bit of confusion about how you are asking your question and your hypothesis. Your gradient is moving from riparian to upland forest. It also sounds like you believe it to be along a successional gradient, but what evidence do you have for this? Also, if it is along both a successional gradient and a wet – dry gradient then you will have a hard time saying which is resulting in the changes to poplar that you see. Could the younger poplars adjacent to the river be due to water levels?
So, your response variable makes sense and you have a good gradient, but you need to work on your hypothesis and your what you are measuring for your predictor variable. Right now your predictor variable also doesn’t seem to be related to succession. You could simply change your hypothesis to be related to nutrient availability.
Thank you! the gradient is starting in a flood plain which gets submerged every spring for a couple months. So I was assuming that no other trees can grow in those conditions but the poplar. This assumption made me to believe that poplar trees are a first succession trees due to their ability to withstand various conditions and have faster growth rates. but I understand what you mean because that is hard to measure. here is my updated version.
hypothesis: The rapid growth and short lifespan of populous Balsamifera create favourable conditions, such as increased nutrient availability and accelerate succession to support and facilitate growth of other species of trees in their vicinity.
would this work?