User:Shiyue Chen/Strawberry Creek

History
Strawberry Creek used to be the greatest source on the Berkeley campus to serve an educational, environmental, and recreational purpose. However, the water pollution due to urbanization in the beginning of the twentieth century has degraded the environmental quality of the creek. In 1987, a program dedicated to improve water quality and reintroduce native species was a success. The condition of Strawberry Creek was restored to satisfaction in 1991. Since then, environmental education and restoration programs continues to monitor the quality of the creek.

Fish
Strawberry Creek used to have around 13 native fish species, including coldwater salmonids, anadromous steelhead and coho salmon. However, observing fish was difficult due to pollution, decrease in fish population, and poor water quality. Therefore, historical tend data was not available, so the reintroduction data was majorly based on recent studies. Since then, five species have been reintroduced to the creek: three­spined stickleback (Gasterosteus aculeatus), California roach (Lavinias symmetricus), California Hitch (Lavinia exilicauda), Sacramento sucker (Catostomus occidentalis), and the prickly sculpin (Cottus asper).

The attempts of reintroduce native fish were not successful. First, the water quality of the creek was good enough for fish to inhabit. Water quality tests confirmed the water contained a disturbing amount of mercury and coliform, which was dangerous for not only humans, but also animals that contact with the water. The sanity issues were partly caused by improper disposal of garbage and poorly engineered drain system. Secondly, high flow rates, and more importantly, great difference in flow rates is a great concern for reintroduction of fish. High flow rates can be up to 118 times faster than the regular flow rates at the same location. High flow rates was caused by the construction of dams along the creek. Reintroduced fish were not able to inhabit under such circumstances. Finally, the introduction of a non-native fish, Pacifastacus leniusculus, or Crayfish has a negative impact on the native fish population. Crayfish is more aggressive than the native fish species in predation, therefore, has a potential to threaten local fish abundance.

Plants
Since urbanization, new species were introduced to Strawberry creek. The invasion of exotic plants has endangered the existence of local seedlings. Low biomass of native seedlings is caused by the competition of water in the soil. Exotic species have different rates of growth and evapotranspiration, which changes the soil moisture of the creek. For example, Algerian ivy and English Ivy has taken over the native habitat. They required minimum management and were capable of absorbing pollution, therefore, they were able to spread quickly and dominate the creek area. Ivy has decreased the soil moisture, which even harder for native species to survive.

Land use
University of California, Berkeley has developed the upper Strawberry Creek watershed. Berkeley central campus, including parking lots, open areas, roadways, and Lawrence Berkeley Labs were built in this area. In addition, recreational structures such as Kleeberger Field, Memorial Stadium, and the Hats Recreation Area were constructed in the area. The total urbanized areas in the watershed comprised about 37% of the total area.