Will You Be There for San Juan Islands?
How did San Juan Island really look like 200 years ago?
Last Friday the S Pod had a case study discussion on sustainability. I chose an article entitled “Global Consequences of Land Use” by Foley et al, published in Science in November, 2005. The article pertains primarily to the effects of agricultural land use on land cover. One aspect I find intriguing is soil salinization, a phenomenon common in agricultural lands. Heavy irrigation of soil, coupled with removal of deep-rooted native vegetation, cause water table to rise near to soil surface. A disturbance such as heavy rainfall can then draw water levels to the root zone. When this water is evaporated from the soil surface, the salt is left behind, causing soil salinization, which quickly deteriorates soil quality.
Our Beam Reach instructor, Dr. Scott Veirs, mentioned that one common problem on San Juan Islands is the overwithdrawal of groundwater, causing salt water to seep into the aquifer. This led me to think more about the land and resource usage on San Juan Islands. In a conversation with Jason Gunter, owner of Discovery Sea Kayak, I found out that before English and American settlers arrived at San Juan Islands, the Native Americans practised controlled burning of open lands in order to better harvest bulbs. It has been speculated that at the time, many parts of San Juan Island were not forested. The theory is that controlled burning allowed slow-growing trees such as oak to mature. When controlled burning stopped, tall and faster-growing conifers such as Douglas fir out-competed the slower growing species by creating shades. These conifers propagated, which gradually brought about the landscape we see on San Juan Island today.
Jason has also mentioned that this change in land cover has caused the loss of a few species of birds. It would be very interesting to find out how land use and land cover have evolved for the past 200 years, and whether this has impacted the local nearshore or marine ecology in any way. Nonetheless, I think it is even more pertinent to study the current land and resource usage on San Juan Islands, in order to modify and adapt resource usage to ensure the continuous availability of these resources — such as potable water and fertile soil — in the future.
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