Statistics

Last semester I took many classes that taught principles that built upon each other. Not only was I able to have a greater understanding for these subjects, but I was able to save valuable time studying. Luckily, I have come across the same scenario here with Field Ecology and the statistics portion of this class. Similar to this class, we got a quick and dirty intro to statistics in field ecology with introductions on X^2, t-tests, type I and II errors, variation, etc. As we review statistics (slightly more in depth than in Field Ecology), I have begun to understand the full implication of these statistical analyses rather than, for example, what alpha and p-values specifically mean for the data I have gathered. I am now contemplating taking a statistics course next semester if I happen to get screwed-over by the Jackson School and can't graduate this semester (which might happen). 

The beginning of field work...

Luckily, I have performed much of the field work that is necessary for my research before in Field Ecology. As I have performed field work for this class, it was stressed to us that it is important to work quickly and efficiently, but to always be aware of the details. Sloan, Josh and I will begin our field work on Friday (23rd) on the downstream impacted sites in Slaughter Creek that do not require a permit, or permission to enter the site. We have decided to conduct our work together for safety, but also because we are generally interested in each others field methods and what each of us will find. I expect that our first day of field work will be slow as we establish a rhythm. Hopefully, after our first day, we will learn to work quickly. Our goal is to conduct a couple of field work days before we begin work on the WQPLs. We would like to become familiar with our field methods and our efficiency before we work of these highly regulated lands.

Permit Update:
I have submitted (Monday March 19) my research proposal to Kevin at the city for review and he has informed me that the review process will begin this week.

Justifying transect size...

As I combed through the literature looking for suggestions of how to implement my vegetation surveys, I struggled with the size of my transects. Most of the literature did not reveal transect size, but transect area. Also, the spatial scale of much of the research in the literature was greater than I would be able to accomplish in one semester. After talking with Megan, she suggested that I visit the reference site of Slaughter Creek, Bull Creek at St. Edward's Park, and establish a transect size there that will be manageable, but also include an appropriate diversity of environmental factors that normally influence riparian habitat integrity. Then I will normalize this area to my controlled (WQPL) and impacted (upstream and downstream) sites along Slaughter Creek. I think this is a practical solution because the width of the riparian zone, from the stream outward (or upland) will differ at each site. If I were to choose transects with fixed dimensions, I believe that I would not have the wealth of data I would need to appropriately apply statistical analysis on my data.
Below is an image of my reference site Bull Creek at St. Edwards Park that I created from Google Earth:

Expermiental Design: How to avoid pseudoreplication

My research group struggled with experimental design to avoid pseudoreplication in all of our data as we will all be sampling data in the same stream, Slaughter Creek. We found ourselves asking if there was a great enough spatial scale to avoid treatments not being replicated even though our samples would be. We also wondered if our replicates would not be statistically independent due to our limited spatial scale within one creek. To avoid pseudoreplication, I planned the location of my impacted sample sites throughout the whole watershed of Slaughter Creek, both upstream and downstream of the WQPLs. In this way, the treatment I am measuring (protected land) will be compared to impact sites both upstream and downstream of the WQPLs. Because I will not be able to measure multiple treatments (sites at multiple WQPL tracts in multiple creeks), I will not be able to isolate all random factors from fixed factors, but I will remain keenly aware of this fact.

The map below shows the WQPL tracts along Slaughter Creek (Baker, Hafif, Hielscher).

Field Techniques in Upper Barton and Waller Creek

On February 13th and 20th we conducted macroinvertebrate surveys in Upper Barton Creek and in Waller Creek. We found a greater diversity of macroinvertebrates in Upper Barton than in Waller. Waller Creek is far more impacted by urban development than is Upper Barton Creek and is found to be a flashier creek. Urban impacts on water quality may have an effect on the diversity of the macroinvertebrate community found in Waller Creek, but also the altered landscape. There is less tree cover over many stretches of Waller Creek than Upper Barton Creek and the riparian zone was more fragmented. Extensive tree cover to help regulate water temperature and a healthy riparian zone may contribute to a higher diversity of macroinvertebrates in Upper Barton Creek.

The macroinvertebrate survey was not directly applicable to by research, but other techniques we learned during these two trips were. The first, was the EII habitat assessment that the City of Austin performs at their field sites. As we completed this habitat assessment with Liza and Todd, I learned how to normalize an environmental condition to a reference site, or a site the is considered ideal in the same region. I also learned how to accurately judge environmental conditions such as bank stability and vegetative protection based on a wide perspective of observations rather than a few. Secondly, I learned how to use a densiometer to estimate percent cover in Waller Creek. Hank, Tim and I estimated percent cover (by counting and estimating open dots in each square of the frame) for each of the three macroinvertebrate survey sites along Waller creek. At each site, we measured percent cover facing downstream, upstream, and downstream at the bottom, middle and top of stream riffles, respectively.

Spherical densiometer

What I have gained from these two field days is three methods that I will be using in my own research. I plan to use the same diversity index we used in class (Simpson's) to calculate vegetation diversity in the riparian zone of Slaughter Creek. Additionally, I plan of using the CoA EII Habitat Assessment Worksheet to help establish the basic stream characteristics of each site I am sampling. And lastly, I will also be calculating percent tree cover at various sites in Slaughter Creek. Instead of using a densiometer, I will use a digital camera with fish eye lens and a computer software (Gap Light Analyzer) that calculates percent open space.

Switch, continued...

We continued, and finished watching Scott Tinker's documentary "Switch" on February 14th. Dr. Tinker wrapped up his world wide survey of cutting edge energy facilities and began to talk about the efficient application of energy and how we use it. A switch in our current energy paradigm is possible, says Tinker, but it will take a long time. Specifically, the introduction and common use of alternatives will require scaling-up, which will pose challenges because each source of energy supply has it's weaknesses. These challenges can be faced by integrating energy sources. The intermittency challenge from one major source of energy to another is too great. Nuclear and natural gas have the potential to be fundamental energies, but not until the combination of natural gas, nuclear and renewables do we see oil and gas being overcome as fundamental energies. There is also a tremendous goal we must set for ourselves in our own efficiencies. Simple action can be taken by paying close attention to our own energy use that will help us use less and emit less.

Switch, a documentary by Scott Tinker

Beginning February 7th, we watched Scott Tinker's documentary "Switch." To briefly summarize this documentary, Dr. Tinker, the director of UT's Bureau of Economic Geology, guides his audience through the current state of energy use in the US and world wide. Then, he almost takes a tour around the world as he visits the  most progressive energy facilities from Norway to France, and Texas to Canada. I thought this documentary was very well organized. Dr. Tinker discusses our energy use, demand, and challenges while providing current examples of how the US and the world can make a transition to more renewable and sustainable energy sources. In general, the US is beginning an energy transition from coal and oil to natural gas, nuclear, oil sands, geothermal, solar, wind, and biofuel.

One of the most compelling examples of how a shift in energy use can be made is in nuclear power. There are profound differences in how the US and France approach nuclear power and nuclear waste generation. The reason for this is the economics of nuclear supply. When Dr. Tinker visited a nuclear facility in France, he found that they recycle 96% of their nuclear fuel source leaving only 4% of the original nuclear waste. By recycling their nuclear fuel source, they reduce the volume of waste and they create a highly efficient reserve of energy supply. I hope that the US can use France's nuclear energy system as an example to follow since the storage of nuclear waste is costly and a national security risk. Currently the US does not have an incentive to efficiently use and recycle nuclear waste since our domestic supply of uranium is not limited. This serves as an example of how our energy policy is not progressive, but reactionary. It may take a substantial economic push to begin to recycle nuclear waste.