8th Drop: Valuation & Modelling of Ecosystem Services in Pongola Floodplain, South Africa

~ HEY THERE! Thanks for coming back and reading :) Hope everyone had a good week

Valuation of Ecosystem Services for Policy Making

Now after all these points about the concept of ecosystem services, how it can be implemented and how valuation of different services can be carried out, a more fundamental question is why do we adopt ecosystem services valuation? There is greater recognition of the importance of viewing our environment as interconnected and complex systems/ processes (i.e. as a larger ecosystem unit) rather than as individual ecological units. More importantly there are undeniable trade-offs between conservation and development. Thus valuation of ecosystem services can be seen as an imperative to help create greater awareness about the need for conservation (when in reality would likely have not existed if no economic valuation is placed on the environment) and facilitate a more informed decision making process. The article that I am going through today hence showcases how valuation and modelling of ecosystem services in a river system can help support policymakers' decision making process.

Modelling of Water Allocation and Ecosystem Services in Pongola Floodplain

The Pongola Floodplain in South Africa is highly dependent on the annual summer floods and hence river flows from the Pongola River system. However the creation of the Pongolapoort Dam - primary purpose was to control floods and provide an assured water supply for irrigation of ~40 000 ha of land adjacent to the floodplain - has greatly altered river flows. The consequent impacts on floodplain ecosystems and downstream users are thus significant and cannot be overlooked. Lankford et al. (2011) thus talks about the Pongola River Ecosystem Services for Poverty Alleviation (PRESPA) Project, which quantified the economic benefits provided by the water resources of the Pongola river and floodplain to the 8 different livelihood sectors identified by the authors. PRESPA project undertakes eco-hydrology modelling of 3 developmental scenarios of regulated flow release by the upstream Pongolapoort Dam to explore trade-offs and outcomes of poverty alleviation through; (1) status quo of unregulated releases and unstructured economy; (2) regulated releases and structured diverse economy; and (3) structured 'single sector' agriculture economy. It is hoped that the results from such a modelling project would help inform policymakers on the options and trade-offs of various development scenarios and thus support such decision making.

Once again here are some of my thoughts:

1) Modelling results: Comparing of various economic benefits attained

• Scenario (3) shows highest economic value acquired in total as well as for the poorest
• Important to consider societal contexts, distribution and equity issues?
• Values assigned to (3) assumes full participation (production & labour) and no political barriers hindering full uptake of irrigation schemes (planned 40 000 ha)
• Authors also noted that values only captured provisioning services
• Values for (2) are underestimations; regulating & supporting services left out
• Values for (3) possibly overestimated? Hydro-ecological feedbacks due to altered river flow?
• Scenario (2) may be more equitable; allow diversified economy and accommodate livelihoods
• Authors utilises the scenarios to highlight the variety of 'futures' possible for the floodplain
• (3) appear to alleviate poverty in short term but pose long term repercussions
• Scenario (2) more sustainable in the long run; more resilient environment and economy
• Clearly (1) represents the most undesirable scenario: call for action of more active management

> Ecosystem services valuation and modelling are nonetheless still just merely estimations as highlighted by the case study. However these estimations are still valuable because they allow decision makers to more weigh more accurately the pros and cons of various scenarios and hopefully make a more informed decision. At the same time, i do feel that we must not romanticize conservation and miss out on key developmental opportunities, especially if scenario (3) seems more economically beneficial and environmental consequences can be effectively mitigated and addressed. 

2) What to make out of such modelling exercises?

• Clearly invaluable in considering different future scenarios and in supporting decision making
• But must be critically analysed, such exercises can also be inherently subjective?
• Variables taken, choice of what services to be considered and calculations used?
• Case study of PRESPA seems to have made fairly reasonable assumptions and choice of valuations
• Case study did not consider the complexities/ uncertainties of ecosystems and climatic chan
• Possible improvements if regulating and supporting services are considered as well? Using proxy values/ estimated using related provisioning services as covered previously?
• Improvements of considering changes in climatic conditions as well?
• More complex eco-hydrology model but definitely useful to help make a more informed decision

> Such modelling exercises are definitely invaluable in helping policymakers make a more informed decision and choice based on an ecosystem service framework. Within the case study, clear and important learning points on the need for better management and poverty alleviation have been made. That said models are hardly ever complete and improvements can always be made. The choice of models and their various calculations thus depends on what the models are meant to be used for. Regardless model results should never be taken without critical analysis, especially when talking about ecosystem services because there are clear uncertainties and complexities involved.

* Point of reflection: This article also reiterated a previous article's point on trade-offs between ecosystem services! :) I also do feel that valuation of regulating services and supporting services can be undertaken by the model through the related provisioning services as highlighted in a previous post.

THANKS for reading through this post! Hope this was a slightly shorter and refreshing article for you guys :)

~ Till Next Time ~

National Geographic Photo of Pongola River Valley by Michelle Riley