Friends of Sturt Gorge
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A simple but effective method of monitoring vegetation change To monitor, is to observe and keep record of change in something over time. For example measuring rainfall using a rain gauge over the period of one month, or even ten years. The time intervals and the duration of monitoring will vary according to what is being measured and the purpose of the monitoring.
Monitoring vegetation and habitat change There are many different methods of monitoring change in vegetation, photopoint monitoring is just one. Other methods involve actual counting and measuring the plants themselves over preset areas of ground. Below is an outline of photopoint monitoring. Photopoint monitoring is where a particular point in the environment is chosen and a permanent marking system is put in place so that vegetation or habitat photos taken at this location can be retaken at some later point in time. The use of photos is both a quick and relatively simple method but it does have its limitations.
Photopoints cannot be expected to accurately quantify change to vegetation or habitat, it can however accurately record slow changes over time, which the human memory has difficulty doing accurtely, or gross changes over shorter periods. Provided the general community is committed to repeating the photopoints, photos will keep record of changes to the environment even when the people who live in the area leave, their memories of what the environment was like, leaving with them. Photopoints can be used to monitor relatively slow changes to vegetation or habitat such as regeneration of native plants after:
or to monitor the rate of dieback of vegetation by observing canopy changes Top of PageSite selection and photopoint post location
Using the sledge hammer fix a star dropper into the ground, the height remaining above ground should preferably be close to eye height of the average person (~1.4 - 1.6 metres). This becomes the ‘camera post’. This allows the photographer to rest the camera on the top of the post while taking the photo, and for consistency, sets a height standard from which the photo is taken. Another star dropper should be placed 10 metres in the direction you wish to take the photo. This becomes the ‘sighter peg’. The camera post and sighter peg should be firm enough in the ground so that they are difficult to remove. If vandalism is a problem and camera posts get removed, small marker pegs semi-buried at the base of each camera post, at the time of installation, will probably not be removed and will assist in relocating the original positions. Ensure the camera post, from which the photo is taken, has the labelling tag with its identification number attached to it by wire or tie. Again if vandalism is a problem and the tag is at risk of removal, place a post with the identification number on it, semi-buried in at the base of the camera post, at the time of installation.
Before taking the photo, a data board should be placed in the field of view preferably at the top of the sighter post. This needs to have written on it the date and the identification number, which is also on the tag of the other post. The writing needs to be quite large so that it can be read from the photo itself once developed.
On a data card note the following: photopoint number, date, location, direction of photo, purpose of photo, print negative number, and observations at the site at the time of the photo eg regeneration, grazing pressure, seasonal conditions, signs of rabbit activity. Recording these observations is important. This information will enhance the value of the photo as it provides details which may not be picked up by looking at the photo afterwards. Obtain a print copy of the slide and stick this on to the data card See Figure 2 for an example data card
This will depend on the purpose of the monitoring and the environmental conditions. For example, to pick up ephemeral plant growth in the rangelands, a sequence of photos approximately 2-4 weeks apart after heavy rains will show germination and growth rates of the ephemeral plants. To pick up seasonal changes in the agricultural regions of the state photos may need to be taken 2 times per year. For example, Autumn and Spring will generally show the differences between native verses exotic plant growth. Particular events such as flood and fire would be typical reasons for increasing the initial frequency of monitoring. In these cases, the first few shots could be 2 monthly for one year, then 6 monthly for one year, then annually, or biannually etc. In other words, the frequency’ of the photographs depends on the expected rate of vegetation change. If this cannot be predicted, err on the side off caution and increase the frequency of photos taken to ensure the change is well recorded.
Interpreting the photo series: some disadvantages Photopoints cannot be expected to accurately quantify change to vegetation or habitat. Let’s say that the difference between a series of photos over time showed the vegetation was thickening or growing in the field of view. Some photos will be able to show that the growth was from new seedlings as well as ongoing growth from existing perennials. What could not be concluded from the photos however, is the number of seedlings which germinated but were then eaten or died from other causes. This type of information is best recorded by finer observations and measurements of the vegetation on a more frequent basis. Should such information regarding vegetation change be required, imaginary 1 x 1 m quadrats can be set up within the area between the two photopoint posts, see Figure 3. This will require a good botanist who is prepared to make the additional set of records and return for the long term monitoring.
If this were to be done on a weekly basis, losses could be counted as well as the survivors. Losses would be noted by placing pegs next to the seedlings as they emerge, at some later time, a peg may be noted but no seedling is present, hence you could safely conclude that the seedling had died (provided the pegs had not been tampered with).
Even infrequently recorded photo points will show change over time. The resulting photo-series can, in time, provide a cost effective means of determining trends in the vegetation / surface cover of an area. If causes of the vegetation changes are to be evaluated, further observations will need to he taken.
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