Ecology Exercise 2 - The distribution of species across a footpath

This resource is designed to give students an opportunity to see how systematic sampling can be used to

• investigate changes in species richness across a footpath
• the distribution of species across a footpath

These exercises are not intended as a substitute for practical field work. They do however, provide an opportunity to introduce fieldwork sampling ideas and some basic ecological principles in the classroom before going out into the field

The site chosen

The footpath runs through across chalk grassland, a vegetation rich in species. The gridded quadrats are placed along a transect running from the middle of the path into the edge of the untrampled grassland

Resources

1. A diagram of the transect line showing the positions of the quadrats with hotlinks to the quadrats (Follow link to view)

2. Images of eight gridded quadrats supplied as separate images - these are linked from the transect diagram.

3. Identification sheet naming species which occur in the quadrats. No attempt has been made to separate the grass species or the mosses. This obviously affects the results for species richness and should be discussed. (Download 'Ecology Exercise - ID Sheet' from link on right)

4. A table for recording results.(Download 'blank results sheet.xls' from link on right)

5. Species richness results (Download 'species richness data.xls' from link on right)

6. Local frequency results for the two plantain species. (Download 'frequency plantains data.xls' from link on right)

Suggestions for carrying out the exercise

Introduction

Discuss with the students how a possible pattern in the vegetation e.g. changes across a footpath might be investigated. Describe systematic sampling and its various uses (see Osmosis 2004).

Consider some of the changes that might take place along a transect across a footpath. Brief notes are given here to help you.

Relatively few species are able to tolerate heavy trampling. There is usually a decrease in the number of species (species richness) towards the centre of the path. (Note species richness is not the same as species diversity which takes into account the relative abundance of each species as well as the number of species.)

Many of the species which tolerate trampling well are able to exhibit the rosette growth form and have their growing points situated close to the ground.

Even closely related species vary in their tolerance to trampling. Greater Plantain is said to be more tolerant of trampling than the Ribwort Plantain.

For more information see the website references below.

Practical

• Measuring species richness at different points along the transect

Allocate a quadrat to each pair or small group of students.

Using the recording sheet ask them to count the number of different species that they can see. And enter this data into a class spread sheet.

It is not necessary to identify species to measure species richness. With more able students, however, you may wish to make the exercise more interesting by asking them to use the identification sheets to identify the different species they can see. This data can be recorded using the table given.

• Investigating the distribution of Greater Plantain and Ribwort Plantain along the transect

For each quadrat ask the students to record the number of squares each of the two species of Plantain occurs in (i.e. their local frequency) This information can then be entered into the class spread sheet.

Links

For more information about quadrats and sampling see ‘Questions about quadrats’

For practical fieldwork ideas and information look at the Field Studies Council website Urban Ecosystems - Urban habitat 1 Grassland -

http://www.field-studies-council.org/urbaneco/