Studying Land Use/Cover Change in the Collins View Neighborhood
Background
In focusing on Environmental Analysis in the Anthropocene, a current question worth heavy exploration is in the way ecosystems and patterns are disrupted by the increased transformation and development carried out by humans. Every day, we are seeing changes and shifts in ecosystems, watching urbanization grow, and a disruption occur for native vegetation and species. But how do we find the the effects that correlate with our development of suburban neighborhoods, and urbanization to accommodate to a growing, technology-hungry population? This question spurred the decision to carry out some observations in and around a neighborhood near the Lewis and Clark College campus. By collecting temperature and humidity data from points in a similar region, but with various levels of vegetation cover and urban development, we can begin to distinguish possible effects being incurred.
Procedure
We carried out experimentation by collecting temporal data from twelve various land cover sites in the 97219, Southwest Portland area. After first looking at satellite data on the Google Earth Engine Time-lapse to see overall landscape changes over the last thirty years, we compared current satellite images to an image from seventy-nine years ago. This gave us insight into our land cover site before arriving, as what is now a well-developed suburban neighborhood was once a barren dirt lot, lined by dense forest on its southern edge.
From here, we went out to our sample land cover sight (an approximate 30m by 30m square around our coordinates) to find a centroid and establish a set-up point nearby for our Kestrel Drop microclimate sensor. The Kestrel Drop was set up in the shade (northern side of a tree) so as to retrieve more accurate results, and was left for twenty-four hours to collect temperature and humidity readings, allowing us to track the changes over that period in this specific area of this now-developed area. After picking up the Kestrel Drop the next evening, the data was then transferred to my phone to analyze.
Analysis & Results
Our coordinates of a latitude of 45.4533 and longitude of -122.6871 degrees brought us to the front yard a home in a “well-utilized” neighborhood dense with houses, developments, and recently landscaped vegetation. Growth rates seemed to vary greatly, and much of the vegetation was not native. While there has been immense, diverse growth (trees ranging seemingly from one year old, to seventy years old), much of the vegetation seemed to be dry or already changing colors for fall, as if warmer weather than normal is affecting the area (or perhaps lack of sufficient water). After setting up our Kestrel Drop, a gentleman came out of the house to ask how long it would be there, as the tree was being torn out in just a few days when they were planning to re-landscape. An interesting sight into how often this ecosystem is being disrupted, and yet continuously developed.
Discussion
While this overall temperature shift was due to the change in weather (sunny clear Thursday, cloudy cooler Friday), the temperature shift seems to also be influenced by the location of so much asphalt and human development nearby. In an area with so much asphalt and concrete, it seems that these may have influenced the larger temperature drop in the evening, coinciding with a much higher temperature with direct sunlight. This would explain observations in previous research that cities tend to experience more diverse temperatures than in non-manipulated ecosystems.