Ecosystem Analysis

Ecosystem Analysis Objectives: 4.02 – 4.05, 4.16 Introduction: Abiotic components of an ecosystem may vary in space and time. Biotic and abiotic factors define an ecosystem. For example, the percent relative humidity and light intensity will differ as one moves from a field to forest. An ecotone is a transitional zone observed between two ecosystems. In an ecotone, representative species from both ecosystems may be observed. In addition to an overlap in species, a change in abiotic factors will also be observed. Succession is a predictable pattern of change that occurs within ecosystems. Primary succession is the establishment of life where it did not exist previously. Pioneering plants are the first type of plants to arrive. The continuous replacement of one community with another us referred to as succession . Eventually a plant community becomes established that is able to maintain its species, new types will not invade the area. The last stage of succession is the climax stage, and it may take decades or centuries for an ecosystem to achieve this stage. In today’s laboratory you will have an opportunity to evaluate two adjoining ecosystems. Evidence of succession and changing abiotic factors will be evaluated. Experiment: Part 1, Abiotic factors of terrestrial ecosystems Introduction : In this exercise you will establish a 100 m sampling line bisecting two adjacent ecosystems. Environmental measurements will be taken at 10 sampling stations evenly distributed along the established sampling line. A plant survey will also be conducted at each sampling station as well. The collected data will be analyzed, interpreted, graphed and discussed. Directions: A 100 meter field tape will be used to determine a sampling line between a short grass and forest ecosystem, and the ecotone between. Every ten meters, representative species will be evaluated. Record your data in the table provided (at the end of the lab). Group 1: Sampling Line 1. Equipment needed a. 100 meter field tape b. Compass c. Sample flags 2. Directions a. Select a location that bisects between two adjacent ecosystems. b. Establish a flag as station 1

c. Using the compass, establish a heading for the sampling line (not degree reading) d. Every 10 meters place a flag, keeping the sampling line as straight as possible Group 2: Physical Conditions 1. Equipment needed a. Soil thermometers b. Thermometers to measure air temperature (or other) c. Wind velocity meter d. Relative humidity meter (or other) e. Light intensity meter 2. Directions: a. Place a soil thermometer at each sample station, placing the thermometer at the same depth at every station b. After five minutes, record your temperature in o C c. Record the air temperature in o C d. Record the % relative humidity e. Record the wind velocity by holding the meter one meter above the ground f. Record the light intensity, the instructor will demonstrate how to use the unit Group 3: Small Plants 1. Equipment needed: a. hoop b. meter stick c. data sheet 2. Directions: a. at each sampling location place the hoop at ten meter intervals and count the number of plants in each of the following categories: (1) all narrow leaved plants, grasses, etc. (2) herbs over 50 cm tall (3) if plant numbers are numerous, estimate total numbers b. estimate the average height of the dominant vegetation, record in cm Group 4: Large Plants 1. Equipment needed: a. 2 m long string b. meter stick c. data sheet 2. Directions: a. at each sampling point, extend the string in all directions, and count all woody plants. b. if a plant branch is below 1 meter, record it as a shrub. c. if it is above 1 meter, record it a tree. d. if a portion of a tree falls within the sampling area, record the portion that does

DATA TABLES Sample Station Parameter 1 2 3 4 5 6 7 8 9 10 Narrow-leaf plants (e.g. grass) 858 67 5 0 0 0 0 0 0 1 Herbs under 50 cm tall 33 82 7 4 6 10 9 8 5 10 Herbs over 50 cm tall 0 0 1 0 0 0 0 0 0 0 Shrubs (branches 1 m or less) 0 5 0 0 0 9 1 0 1 0 Trees (branches above 1 m) 0 0 0 0 0 0 0 0 0 0 Average height of dominant veg. 8 15 21 10 18 30 2 17 6 5 Air temperature ( o C) 24.6 24.1 24.2 23.8 23.4 23.7 22.7 23.3 22.8 22.8 Soil Temperature ( o C) 25 15 5 10 5 10 5 10 15 22 Wind Speed 0 0 0 0 0 0 0 0 0.4 0 Light Meter 540 560 52 92 110 100 97 201 133 390 Relative Humidity 49.2 52.7 53.2 51.3 51.9 54 54.1 52.1 53.8 51.3 Parameter Pond Ecosystem Small Stream temperature ( o C) 22.8 18 pH 10.2 7.8 conductivity 159.2 248

Parameter Pond Ecosystem Small Stream dissolved oxygen (mg/l) 7.50 8.42 TDS (total dissolved solids) 77 127 END of EXERCISE QUESTIONS 1. Was ecological succession observed? Provide evidence to support your answer. Station 1 and 2 had more narrow leaf plants and herbs then the rest of the stations. 2. Was an ecotone observed? Provide evidence to support your answer. It was when we went from station 2, to station 3 as we transitioned from the grass to the woods. 3. Which abiotic factor changed the most across the sampling stations? The Light meter 4. Which abiotic factor changed the least across the sampling stations? The air temperature. 5. Explain why there was a difference between the dissolved oxygen levels between the stream and pond (lake). Moving water dissolves oxygen way faster then stationary water like a pond or lake. 6. Prepare the following graphs identified below representing your data. All graphs must be included in the report. Using MS EXCEL, cut and paste the completed graphs in the report. If making hand-drawn graphs, take a photo of the completed graphs and insert them directly into the report. Please refer to the example below. a. Graph 1 : (line graph): sampling stations (horizontal axis) vs. soil and air temperature (vertical axis), color code your lines, include a legend, label the legend, include title and labeled axis and units

Graph 3 :

Graph 4 :