Purpose: Present an analysis method for survey results from beach litter inventories on Lake Geneva.
Background: This is in the context of the global movement to reduce plastic debris in the maritime environment. Riverine inputs are major contributors of plastic debris (and all types of refuse) to the oceans. This is an analysis of the data collected on the shores of Lake Geneva over a three year period. The maritime protocol was modified in very specific ways to adjust for the local geography and population density.
There is a push to quantify the amounts of plastic trash in the environment. It would be impossible to pick up every piece of trash in the environment and count it (that would solve the problem though). Extrapolating from economic and population data is one way to obtain a macro-view of the problem. But the margin of error on these type of calculations makes them unsuitable for identifying trends on a local or regional level.
If sampling all the trash is not possibile, what if we sample as much as possible and see what that looks like? The following questions could be answered:
These series of notebooks will try to answer those questions.
Extract some general descriptive statistics from all samples. Then group the data and compare the individual group results to the all the data.
There were/are many groups on the lake shore concerned by this problem. The data originates from five distinct groups:
How are the observations similar or different when sorted by group membership? The sampling method and conditions leave alot of responsibiliyt to the sampler. What a persons "sees" and how fatigue and environmental conditions effect an individuals attention to detail and motivation are variables that are part of the sampling process.
Following a protocol and educating surveyors should minimise the effects of those variables. None the less the effects are real and they may have an impact on the results.