User: | Open Learning Faculty Member:
At this point in time I believe the pattern I have noticed and researched is the result of numerous ecological processes. The successful germination and/or survival of alder seedlings is not as easy and prolific as as I once thought. So far, according to my research, Alnus rubra’s ability to spread can vary significantly from region to region and from season to season. This is believed to be due to differences in how wet or dry the area is, availability of sunlight, availability of exposed soil, and competition. Even with this information, prediction of germination and survivability seems to be difficult to predict.
Focusing on my own site of interest, it may represent a shoreline that was once a good spot for alder to spread, but has changed significantly over the last 100 years. Here are a few ecological processes I believe my study may involve:
Erosion
I recently found some heritage photos dated to about the mid-1900s that feature the shoreline about 500 meters to the north. It’s clear that it the shore has receded many meters from where it once was and more trees were present along the shore in the past. I believe that a portion of my work may involve the subjects of disturbance and succession in that as the shoreline continues to erode the collapsed areas are quickly colonized by blackberry, ivy, and vigorous or invasive plants rather than alder.
Biotic factors
It’s also possible that this area experiences a high enough level of moisture that fungi or pathogens are present and quickly kill off any young seedlings that do germinate.
Availability of sunlight
I need to evaluate the potential ages of the trees in the forest area further to the east of the shore. It may be possible that the mature alders along the shore are actually older than the evergreen trees in this forest. If this is the case, the alders may have germinated at a time in which the forest was logged, therefore plenty of sunlight could reach the shore for most of the day. Now, years later, a forest of evergreens stands much higher than an alder could ever grow, blocking the sun until it makes its way far enough west to strike the shore in the late afternoon and evening only.
Keywords:
Interspecific competition
Biotic influences
Erosion disturbance (and succession)
Microclimate
