Thursday, February 24, 2011

Pictures are worth many words

Hopefully the flash works since I decided to try putting pictures in a slideshow for the sake of saving space. However, if it doesn't, I have provided the link to the album here.

To better narrate the story, I spent a few hours sorting through the arthropod samples that Lizzie had in the fridge, measuring their lengths, drying them, and then weighing them for their mass. Later on, we hope to be able to determine whether or not there is a correlation between arthropod weight and amount of herbivory on the shrubs.

The rest of last week was dedicated the remaining shrub samples and sub-samples that were still in the fridge. I separated them into new growth and old growth bags, with new growth being anything that contained leaves and were still "green" and old growth as everything else. These bags were also popped into the dryer, which sat there for ~96 hours each before I were able to measure their weight. To account for the paper bag weight, I also included 4-5 empty paper bags which were dried as is and weighed before I took out the samples. I'll most likely be adding more information here later on to show what our analysis of the data brings us. Hopefully it's something exciting!

Sunday, February 13, 2011

Mas o menos fin!

I'm happy to report that manual data recording of herbivory is finished! After editing the excel sheets and entering the data, Lizzie wrote up several R codes to run the data through some statistical analysis and to plot them out. I was able to run them again myself from my trusty laptop, and here are some of the charts for the data:

This is the histogram of different shrubs to the total number of herbivory counts. Fortunately, the graph isn't right or left skewed.
This is the plot of total herbivory in relation to the type of treatment. From the looks of this, there isn't much herbivory variation between the different types.
Analysis of Variance Table

Response: tot.herbiv
                 Df      Sum    Sq Mean Sq   F value     Pr(>F)
Trmt           2      3580      1790.1        0.4844     0.6239
Residuals  18     66516     3695.3              

In the previous post, I had hypothesized that there would be the greatest variation of herbivory counts between the control and exclosure, but the analysis and plots of the data entered shows otherwise. In the meantime, I've separated the arthropods that Lizzie vacuumed off of various shrubs from last year, measured their lengths, and have put them in the dryer, which will then be weighed to determine their mass. I will also be separating and drying new from old growth on the shrub samples to be weighed so that we can determine the ratio of herbivory to biomass. After Lizzie and I meet tomorrow, we'll be coming up with the next few steps of what's left to be done, and hopefully we'll have more conclusions to display when we finish.

Thursday, February 3, 2011

Short, but sweet

Hello everyone!

Shrub sub-sampling has been great so far. It took a while, but I have finally established a rhythm and method of how to count for the different signs of herbivory without having to consult the data sheet after ever observation. From the data that I've gathered so far, I would hypothesize that there would be the greatest amount of herbivory (nibbles and side-crunches) on the shrubs in the bird exclosures and the least amount on the controls. I think that this makes sense since the exclosure would keep out birds that would eat arthropods, creating a top-down control and the amount of damage arthropods would wreak. After I finish the rest of the samples, I will be inputing the data into an Excel sheet and then Lizzie and I will see if the predictions are true. To conclude this short post, I present a picture taken with my point-and-shoot camera through the microscope lens (which took me about 20 minutes to figure out how to do, James made it look so easy...)

I found this cicadellid while sampling. It was very exciting, I ended up poking/playing around with it for a good 5 minutes.

Oh yes, and a Happy Chinese New Year to all. May this year bring about great discoveries and festivities in the Year of the Rabbit.