Assignment 2 Preparation & Tutorial 5

Ecosystem type and functioning on the UTM campus

This assignment is due March 2 or March 4 in tutorial session and worth 8% of the course grade. The late penalty is 10% per day, including weekend days. Assignments will not be accepted more than 5 days late, resulting in a mark of zero. There is a drop box outside the Geography TA office where late assignments must be turned in.


Introduction:

Ecosystem form or type based on dominant vegetation (e.g. grassland versus forest) and position on the landscape (e.g. wetland versus upland) has important implications regarding how ecosystems function and in particular how biotic components interact with physical components. In tutorial 5 and assignment 2, real temperature and soil moisture data collected on the UTM campus across 3 contrasting ecosystems (a wetland, a grassland, and a forest) will be analyzed and interpreted to illustrate how ecosystem type mediates changes in soil temperature and moisture. The TA, Varun Gupta, will present an overview of the 3 ecosystems and monitoring equipment in tutorial as well as how to carry out the data analyses using Microsoft Excel.


Objectives:

To access, analyze, and interpret environmental data collected across the UTM campus to address how soil temperature and moisture vary across contrasting ecosystems (a wetland, grassland, and forest) over different temporal (daily and monthly) scales.


Specific instructions:

Data access, analysis, and graphing:

As well as this sheet, refer to the tutorial material presented by TA Varun Gupta, including his presentation slides available on Blackboard.

Download or open the appropriate data needed below as Microsoft Excel Files. It will be easiest to cut and paste needed data into a new worksheet that has all of the sites on the same sheet. Data are accessible from the UTM Geography main page (http://www.utm.utoronto.ca/geography) under the menubar “Resources” and then “Environmental Datasets”. Note that ‘pond’ refers to the marsh adjacent to the pond, and ‘field’ refers to the grassland.

If needed, align sampling dates and times across the 3 ecosystems so the same times are on the same row (e.g. for the month of November, data logging did not begin at the same time across all ecosystems).

For the date of September 17, 2009 (i.e. late summer; note that September data are in the ‘October’ datasheets), create a line graph with time in hours on the x-axis and temperature on the y-axis beginning at midnight and extending hourly until 11pm (24 data points per site in total) for soil temperature in each of the three ecosystems and the air temperature in one of the ecosystems (one would assume that air temperature is not so variable over the distance of a few hundred meters). Each ecosystem and air temperature should be clearly represented by a unique data series and symbol or line color that is shown in a legend. Label this graph “Figure 1” as well as with an appropriate, succinct title.

Repeat for the date of December 1, 2009 (i.e. late fall). Note that by this date all of the deciduous trees had lost their leaves and both grasses and sedges in the grassland and marshes were brown. On this date, there was a small snow pack (3-5cm deep) on the forest floor whereas snow had melted in the wetland and grassland and soil was exposed to the atmosphere. Label this graph “Figure 2” as well as with an appropriate, succinct title.

For the month of November (which captures most of the leaf senescence in the forest), create a line graph of with the date on the x-axis and soil moisture content (m3 of H2O per m3 of soil) on the y-axis beginning at midnight and extending hourly until 11pm for soil temperature in each of the three ecosystems. To make this figure in Microsoft Excel, one can either calculate daily averages and plot these values over time (with each day as the x-axis data point) or, if the x-axis (time) data are first converted from month/day/year to month/day/year/hour/minute, the entire hourly dataset can be plotted. Each ecosystem should be clearly represented by a unique data series and symbol or line color that is shown in a legend. Label this graph “Figure 3” as well as with an appropriate, succinct title. Note that there was 9.8mm of rain accumulation on November 19.

All three graphs must be labeled with a clear, legible, and appropriate figure title, axis titles, axis labels, and legend (adjust scale and font sizes appropriately). Figures may be printed on the same sheet as long as they are clearly legible. They must be stapled to the interpretation questions sheet that is available as a form fill-able .pdf on Blackboard. Hand drawn to scale figures on graph paper are acceptable, but must be clearly legible and for Figure 3 include daily average data (not a single data point from each day).

Answer the following short questions within the space provided.

Interpretation:

1) Based on Figure 1 for a summer day, which ecosystem experiences the most, intermediate, and the least diurnal (i.e. daily recurring) temperature fluctuation? Briefly explain why these differences might exist between the three ecosystems (point form is acceptable).

2) For a late fall day, do the same patterns still exist as in summer? What was unique about the diurnal temperature dynamics in the forest site that had a snowpack by December? Why would this pattern or lack of pattern occur in this site, but not the others?

3) Based on Figure 3 (which represents soil moisture data for the month of November, a time when the dominant forest vegetation in Southern Ontario transitions from carrying out photosynthesis at the beginning to near complete loss of leaves by the end), what pattern is seen in soil moisture content over this time period across the 3 ecosystems and why?