Water research commission

The development of innovative adaptation strategies

1. Introduction

The purpose of this chapter is to identify and discuss adaptation strategies for the different case study areas.

Extensive literature review was undertaken to establish possible adaptation strategies for the different case study areas. These strategies were discussed and debated during workshops with experts to get to practical strategies that can be implemented.

Two main types of adaptation are autonomous and planned adaptation. In this study the focus will be on autonomous adaptation, in other words, adaptation strategies which can be applied at farm level without support from other levels e.g. policies, etc. The success of adaptation strategies will be evaluated by comparing financial vulnerability criteria of different climate and management scenarios.

From the literature research it became clear that a gap exists in the integrated economic modelling at farm level, which this study is attempting to address. The adaptation strategies that were identified as practical solutions by the expert panels will be discussed in the following sections.

2. Adaptation strategies - Olifants West (LORWUA)

For the grape producing area of Olifants West the adaptation strategies that were identified to be included in the integrated model are:

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  Shift in wine grape cultivars towards cultivars that are more tolerant towards projected climate change
  
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  Increase raisin and table grape production
  
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  The installation of shade nets over table grapes production areas.
  

Shift in wine grape cultivars

The world is experiencing a warming trend. Warming may bring benefits to cool viticultural regions, but is likely to create problems in areas that are already close to the upper temperature limits for the cultivars and wine styles concerned. In these cases, relocation, or replacement with varieties that are better adapted to the higher temperatures will be necessary if it is not possible to ameliorate the effects of climate change through management practices (Woolridge, 2007).

We need to understand regional and wine cultivar difference as cultivars have fairly narrow optimal ranges within which they can produce wines of a certain style. As the climate changes, certain regions may move out of these optimal temperature ranges resulting in altered wine style or even altered optimal cultivars that should be planted (Bonnardot, et al, 2011).

It is important to state that one must take mesoclimatic differences into account. Within a larger area, local climates that are determined by slope aspect, altitude and distance from the sea, can result in average growing season temperatures that are very different (Carey V, 2001, cited by Bonnardot, 2011).

Certain wine cultivars may however be more tolerant to increased temperatures than others and a shift to more heat tolerant cultivars in wine production can also be an adaptation strategy.

The expert panel indicated that within the case study region, white wine grape cultivars that will be more tolerant towards climate change include Chenin Blanc and Colombard. White wine grape cultivars that will be most vulnerable towards climate change include Sauvignon Blanc and Chardonnay.

Red wine grape cultivars that will be more tolerant towards climate change include Cabernet Sauvignon, Pinotage and Ruby. Red wine grape cultivars that will be most vulnerable towards climate change are Shiraz and Merlot.

Increase raisin and table grape production

Raisin and table grapes cultivars in general are more resilient towards climate change projections (Bonnardot, V., Carey, V. and Rowswell, D. 2011). The expert panel agreed that a shift from wine grape production to raisin and table grape production can be an adaptation strategy which will reduce the negative impact of climate change on wine grape production.

Shade nets

Shade netting is used in agriculture to protect crops from either excessive solar radiation (i.e. shading), or environmental hazards (e.g. hail, strong winds, sand storms), or as fully enclosed nets for flying pests (birds, fruit-bats, insects) (Shahak et al, 2004).

The production of table grapes under shade nets has already started to take place in the Olifants West area, but to a limited extent. In other areas e.g. Marble Hall and Groblersdal it is common practice to produce table grapes under shade nets, although the initial main driver was the risk of hail damage.

The expert panel agreed that shade nets over table grapes can eliminate most problems associated with projected climate change and will have the following advantages:

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  More efficient water use
  
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  More consistent yield and quality
  

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  Increase in quality (less wind damage, less quality loss due to birds)
  
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  Lower input cost (lower labour cost due to increased quality)
  

Other adaptation strategies (not included in the model)

The following are a list of adaptation strategies debated but not included in the integrated climate change model:

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  Irrigate at night to save water
  
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  Plastic or mulch cover to conserve moist
  
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  Soil preparation and site selection are important for future plantings to ensure optimum production – rather scale down and eliminate marginal blocks.
  

3. Adaptation strategies – Olifants East (Blyde River WUA)

An increase in average temperatures and seasonal shifts are the biggest threats that the Hoedspruit area faces. The following are problems associated with increased temperatures:

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  Quality losses as a result of wind and sunburn (citrus & mangoes)
  
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  Reduction in fruit set (citrus) as a result of sunburn
  
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  Seedless cultivars are less tolerant to increased temperatures than seeded cultivars – the demand however is for seedless cultivars (citrus)
  

The only adaptation strategy that was identified to eliminate the threats associated with climate change and to be included in the integrated model is:

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  The installation of shade nets over citrus and mango production areas
  

Shade nets

While water efficiency is a key concept to solve water-shortage problems in semiarid areas, shading nets structures in semiarid and arid environments can be considered as an intermediate solution for increasing water use efficiency and reducing plant water stress. It offer many advantages and environmental benefits, this is why an increasing area of crops, including citrus, is being grown under shading materials of various types. It was found that the use of the shading net reduces wind speed within the foliage and helped to decrease fruit dropping. The shade provided by the net does not affect yield and internal fruit quality (ratio of sugar to acid) but may increase fruit average weight and diameter (Abouatallah, et al, 2012).

The Panel of experts agreed that shade nets on citrus and mangoes can eliminate most threats associated with projected climate change and will have the following advantages:

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  Improvement in fruit quality (citrus & mangoes) [less hail, wind and sun damage]
  
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  Less stress on tree (citrus & mangoes) [more consistent yields]
  
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  More effective use of irrigation water (citrus & mangoes) [less evapotranspiration]
  

Other adaptation strategies (not included in the model)

The following are a list of adaptation strategies debated but not included in the integrated climate change model:

• 
  Mulching cover to conserve moisture
  
• 
  More effective management of irrigation systems
  
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  Focus on cultivar development to increase natural heat resistance.
  

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