Thursday, August 16, 2012

Sustainability and Ecological Succession

Whew, it had sure been a long time since I last updated. Working on final projects, graduation, and doing another summer internship has been a lot of work, but definitely worth it. Graduating has been daunting and exciting all at the same time, but I'm now a college graduate with a Bachelor of Arts degree!
I admit that during this recent period I haven't been updating my nature journal or taking as many nature walks as I would like, but I have still tried to watch birds as much as I can. I've noticed that moving back home just 30 miles away from my college has really shown me how the type of habitat affects the bird species that lives in the area. My college was in a semi-rural area with a massave temperate forest surrounding campus, and a rocky beach facing an inlet just a 15 minute walk away. The bird species I would notice the most on campus was the Oregon Dark-Eyed Junco, Spotted Towhee, American Crow, Song Sparrow, American Robin Black-Capped Chickadee and the occassional Varied Thrush, and even more rarely a Pileated Woodpecker. At the beach, I would see various diving duck, Gull species, and the occassional Cormorant.

Now, living at home in a suburban area, the larger birds dissapear, and instead I see a farly dense population of smaller birds in my backyard like finches, sparrows, chickadees, flickers, and wrens. I've even noticed a (robin?) nest built in a maple tree in the yard just above my reach. Perhaps suburban birds are more comfortable living among human populations. Or maybe the birds would need to live closer together because there is a smaller area of "wild" habitat for them to live in, and therefore have less places to hide. I also wonder if a surburban area would have more food than a large forested area.
I also have to take into account that my backyard has different plant species than a large forest. My backyard has more planted non-native flowers, invasive wild blackberry brambles, and only deciduous (leafy) trees. My college has more native foliage, large established decidious trees like Big-Leafed Maple, and Red Alder, and also many coniferious (having needles) trees like Western Red Cedar, Western Hemlock, and Douglas Fir.

The difference in bird populations I'm noticing when I compare my backyard in the developed suburban area, and my college's forested area all has to do with ecological sucession. Wikipedia defines this term as "the phenomenon or process by which an ecological community undergoes more or less orderly and predictable changes following disturbance or initial colonization of new habitat," but in simpler terms, it's the order in which plants and animals colonize an area. For example, when a forest fire destroys a section of forest, certian plants will grow first because the structure of the forest has changed. Fire clears away undergrowth and lets more sunlight in, so sun-loving plants that don't need lots of nutrients in the soil grow first, like small bushes and Douglas fir/Alder trees. Eventually this new growth will become dense enough to allow shade-loving plants like Western Hemlock/Cedar trees to grow, and the older plants eventually die and become food (nurse logs for example) to decomposers like fungi, which then enriches the soil. And someday another fire or another disturbance will cause the cycle to repeat itself.

Humans can also be the cause of ecological disturbances in a negative and positive way. The most common example is logging, or clearing forest for housing and other developments. Sometimes logging can be so destructive that it changes wildlife migration patterns and the area never quite recovers. However there are new methods of sustainable logging where workers can "prune" an area by selecting the trees they want and still leaving the forest standing. But human impact on an area can also be positive, like controlled burning to increase growth, and getting rid of invasive species to encourage species diversity.

So the difference between my house and my college is that they are in different stages of ecological succession. My college is nestled in a large forest that has been growing for 100+ years, while my suburb I live in is a developed area where the forest was cut down to make room for housing developments. However, not all human impact is negative. Some plant and animal species thrive in areas of disturbance and human devlopment, and life will continually adapt to change. The main goal would be to create an area where human development does not destroy an area, but instead in a way where plant and wildlife also have an equal chance of survival. And that, is sustainability in a nutshell! : ) 

So some questions to think about are: What type of habitat do I live in? What stage of ecological succession is this area, and how does this change what animal and plant species I'm seeing? How/Why is this habitat different compared to other areas? What ways does the area where I live help plants and animals to grow? How can I make it even better?

For example, since I like watching birds, I could make my backyard a better place for birds by planting more shrubs for birds to hide in, putting up bird houses, and keeping my birdbath clean. Here's some tips here on living with wildlife on the WA Dept. of Fish and Wildlife's website.

Happy Journaling!