Stage 1: Vancouver Bird and Land Trends
Results
NDVI Results
We can see that the landscape has rapidly developed within a span of a decade (Map 1). The regions of the 1999 map that were once a lush green colour (which indicates the presence of healthy vegetation) is now a beige colour, which represents urban developments or bare ground features. I choose to simply use a visual assessment of land use change because there were errors existent in the Landsat satellite following 2003*.
Map 1: Two maps comparing the NDVI results of Vancouver between 1999 and 2017.
Map 1b: Shows the two comparison maps zoomed into city of Vancouver.
Bird Count Trends
Over the span of 40 years, bird populations have significantly declined in Vancouver as sighting counts have decreased on average by about 1,000 individuals every year (Figure 2).
Figure 2: Graph displaying the trends of the entire bird population over the span of 1976-2016 in Vancouver.
Looking deeper into declining bird populations, I then manually organized the 250+ species into four major guilds. After dividing the bird populations into the four different categories of bird species, I was able to further analyze the trends in the data on a case by case basis. We can see that In-Land Birds and Ocean Birds are declining at a rapid rate while the Predators and Common Bird categories are increasing their population since 1976 (Figure 3 & 4).
Figure 3 & 4: Graphs showing the population counts of each of the four bird categories in Vancouver between 1946 and 2016, as well as their associated trend lines.
It is clear that as the City of Vancouver has continued to develop and expand their urban landscape, bird populations have been steadily declining and conclusions can be made that there is a negative relationship between the two corresponding trends.
*For more information on this subject, please visit the discussions tab.
