Contemporary Ecology

Learning intention: To identify ways agricultural development can be altered to reduce impact on native species in the matrix.

Success Criteria:

• Identify ways agricultural development can be altered to assist reptile movement through the matrix.

• Construct a written piece detailing issues and solutions for agricultural development

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Lesson Sequence

1.  Conservation Implications - Reptiles

2.  Understanding Figures worksheet

3.  Write a Letter

4.  Reflection

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Background Information:

• Please refer to background information above as this lesson still concerns reptile movement in varying crops.

• Management of pasture height can influence species movements but is rarely considered when in management plans concerned with connecting fragmented landscapes. They often opt for tall pastures as it benefits poor-dispersing fauna at risk of agricultural fragmentation, reduces predation and prevents loss of ecosystem function.

• Enhancing movement across matrixes can be achieved by maintaining narrow strips of low vegetation among taller pastures to facilitate directional movement but also minimize predation and increase perceptual range. Strip grazing or mowing pastures directionally between habitat fragments needs to be investigated

• Targeted management of cropping could enhance connectivity for some reptiles in fragmented landscapes. Such as directional sowing between habitats represents an important opportunity to link isolated habitat remnants to facilitate greater directional movements for species who otherwise remain exposed to negative effects of the matrix.    

• Corridors of native vegetation can reduce impacts of land clearing by reducing isolation of remnant vegetation. This is however dependent on remnant size and condition.

• In human fragmented landscapes, population extinctions usually exceed colonisation resulting in gradual decline. The solution to this is often corridors, which are known to have positive conservation outcomes. However predicting efficacy of a corridor is difficult due to varying landscape elements.

• Reptile abundance declines in farming landscapes The condition of remnant vegetation may have a greater impact on reptile abundance, especially loss of shrub diversity as a result of livestock grazing.

• Fragmentation and isolation of populations results in reduced population size, decreasing genetic variation and divergence among populations. Under these circumstances, fragmented populations may face an increased risk of extinction due to inbreeding depression, disease or the accumulation of deleterious mutations

• Although some reptile species appear to be more successful in the agricultural landscape than they might have been prior to clearing, their localized success should be viewed in the broader landscape context. All but one species have declined from up to 90% of their former range due to land clearing. Furthermore, linear strips, even those in good condition, do not provide connectivity for many reptile species, either because they are too narrow (all ,100 m), or because the habitat within them is altered, for example, by grazing

• Populations that are small and isolated face a very high risk of extinction and no chance of replacement

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Conservation Implications - Reptiles (10 mins)

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Split students up into four groups to discuss one of four topics for 5 minutes…

They are to write notes on key ideas. Students must come come up with an explanation WHY the statement is true and consider WHAT the implications are for reptile conservation. 

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1. Reptile populations that are small and isolated face a high risk of extinction and no chance of replacement

2. Corridors or strips of native vegetation between tall pastures can reduce impacts of land clearing

3. Most reptile species are found in remnant vegetation as opposed to in the agricultural matrix

4. The habitat within narrow patches of native vegetation is often altered by livestock grazing along the edges.

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Now the class must form new groups of four so that one person from each thinking group can share what was discussed for 1 minute.

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Understanding Figures (15 mins):

Distribute Worksheet 3: Understanding Figures worksheet to all students. They may wish to work in pairs to help them interpret the diagrams. 

Read through the first page as a class to ensure students understand the diagrams then get students to complete the questions.

You may wish to collect this as an assessment of learning.

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Write A Letter (30 mins):

You have noticed that the wheat farm in town has gone up for sale. New owners have taken interest and at the last council meeting they expressed that they hope to double their production by clearing more land and sowing more wheat. This is because the town has increased in size and requires more supply to meet demand.

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Part A (5 mins): Talk about the scenario as a class. Project an image of the current landscape which is home to the arboreal gecko, Christinus marmoratus . 

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Part B (15 mins): Ask each student to write a letter (half - one whole page) to the farmer who intends to buy the land. Students must consider the following points: 

• A brief introduction: who you are, where you’re from, what you’re writing about.

• Why this is important to you

• What implications the clearing of land may have on native species

• What implications the sowing of more wheat may have on native species

• Why it is important to conserve species such as geckos.

• Any changes they could make to their plans to reduce the impact on native species and reptile populations on their land (think about the direction of crops and or their height).

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Part C (10 mins): Students pair up and read their letters to each other. The pairs should give feedback and constructive criticism on the composure of the letters. 

IF you were the farmer, would this letter provide you with enough information to help you consider biodiversity conservation in your agricultural practice? 

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Reflection (5 mins): How has this learning sequence changed your view on human impact on native species? Are there any changes you can make in the future to reduce impact?