Publications by D. Crookes
Can markets assist by providing support for ecological restoration, and if so, under what conditi... more Can markets assist by providing support for ecological restoration, and if so, under what conditions? The first step in addressing this question is to develop a consistent methodology for economic evaluation of ecological restoration projects. A risk analysis process was followed in which a system dynamics model was constructed for eight diverse case study sites where ecological restoration is currently being pursued. Restoration costs vary across each of these sites, as do the benefits associated with restored ecosystem functioning. The system dynamics model simulates the ecological, hydrological and economic benefits of ecological restoration and informs a portfolio mapping exercise where payoffs are matched against the likelihood of success of a project, as well as a number of other factors (such as project costs and risk measures). This is the first known application that couples ecological restoration with system dynamics and portfolio mapping. The results suggest an approach that is able to move beyond traditional indicators of project success, since the effect of discounting is virtually eliminated. We conclude that systems dynamic modelling with portfolio mapping can guide decisions on when markets for restoration activities may be feasible.
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Papers by D. Crookes
Twenty years ago it was argued that rotational wheat production systems will reduce the economic ... more Twenty years ago it was argued that rotational wheat production systems will reduce the economic risks to farmers and restore soil quality. Here we reflect on this assertion by analysing the evidence of a 12-year data window within a trial on a mixture of crop rotation systems at Langgewens Research Farm, South Africa. It was been found that production systems that include rotations with medics and/or medic-clover show some potential for improvement compared with wheat only, with a combination of the annual legume pasture with an added saltbush pasture showing the greatest improvement when taking into consideration the benefits from livestock production that are derived from pastures. Pastures are more resilient to changes in rainfall compared with wheat only. Planting pastures in alternate years also improves the yields from wheat, and this is beneficial in periods of low rainfall. Rotation systems on this farm that include lupin perform worse than the wheat-only model. Furthermore...
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Journal of Energy in Southern Africa, 2018
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The Southern African Forestry Journal, 2001
Synopsis Natural resource valuation techniques have been applied in recent years to savannas and ... more Synopsis Natural resource valuation techniques have been applied in recent years to savannas and savanna resources in South and southern Africa. Results from these studies have been used to demonstrate the importance of savannas, and to assist in resource-use planning. Because these studies have been conducted to meet different research objectives a large number of disparities exist between studies. This makes comparison of results difficult andidentification of underlying drivers ofvalue is problematic. This paper discusses issues which can lead to differences in estimates of resource value, and makes recommendations for future studies to reduce incompatibilities. In particular, this paper recommends that future studies make full descriptions of the objectives of the study, the background characteristics of the study area (including the social, political, economic, cultural, and biophysical characteristics), the methods used, and assumptions made. In this way, the values reported from case studies may be used in other research and decision-making exercises.
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Journal of Environmental Assessment Policy and Management, 2009
Cumulative effects assessments have been defined as environmental assessments done well. However,... more Cumulative effects assessments have been defined as environmental assessments done well. However, socioeconomic studies within the EIA process seldom adequately address cumulative effects. One of the reasons for this is that the socioeconomic tools used in the EIA process have not been evaluated and, where necessary, updated to address cumulative effects. This article evaluates current and potential tools, from a variety of paradigms, including economic, industrial ecology and systems theory. An unexpected result was that traditional economic appraisal techniques such as CBA performed quite well against identified criteria. In addition, a number of other newer techniques were also found to be suitable. The article concludes with recommendations on how to practically address cumulative effects in socioeconomic studies.
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Journal of Environmental Management, 2013
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This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/authorsrights a b s t r a c t Can markets assist by providing support for ecological restoration, and if so, under what conditions? The first step in addressing this question is to develop a consistent methodology for economic evaluation of ecological restoration projects. A risk analysis process was followed in which a system dynamics model was constructed for eight diverse case study sites where ecological restoration is currently being pursued. Restoration costs vary across each of these sites, as do the benefits associated with restored ecosystem functioning. The system dynamics model simulates the ecological, hydrological and economic benefits of ecological restoration and informs a portfolio mapping exercise where payoffs are matched against the likelihood of success of a project, as well as a number of other factors (such as project costs and risk measures). This is the first known application that couples ecological restoration with system dynamics and portfolio mapping. The results suggest an approach that is able to move beyond traditional indicators of project success, since the effect of discounting is virtually eliminated. We conclude that systems dynamic modelling with portfolio mapping can guide decisions on when markets for restoration activities may be feasible.
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Investing in urban natural assets can leverage relatively high economic value in city economies. ... more Investing in urban natural assets can leverage relatively high economic value in city economies. It is not only the case for highly developed cities, but could also be the case for rapidly developing cities. This is the key message from a case study for the City of Cape Town in South Africa as presented in this paper. It was calculated that the leverage of municipal expenditure on maintaining and enhancing ecosystems is 1.2–2 times higher than the leverage of all municipal expenditure on the City economy. Investing and maintaining a City's natural assets or ecological infrastructure yields economically valuable services that could prove to be an important driver of value addition in a city's economy. It is conservatively estimated that for the City of Cape Town, natural assets yield a flow of ecosystem services valued in the order of R4 billion per annum, within a range between R2 billion and R6 billion per annum. Most of this value for the City of Cape Town is created through the tourism industry, but recreation in parks, open spaces and beaches, as well as specific industries such as film-making, also benefit substantially from the services provided by well-functioning ecosystems. Buffering services to better cope with natural hazards such as coastal surges, flooding and fires in urban contexts are important services from an insurance perspective. As entities focused on service provision and as enablers of economic growth and development, municipalities in rapidly developing urban centrums have the mandate and must create the opportunity to invest adequately in natural assets to maintain a healthy flow of ecosystem services to the benefit of people living in and visiting their cities.
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Twenty years ago it was argued that rotational wheat production systems will reduce the economic ... more Twenty years ago it was argued that rotational wheat production systems will reduce the economic risks to farmers and restore soil quality. Here we reflect on this assertion by analysing the evidence of a 12-year data window within a trial on a mixture of crop rotation systems at Langgewens Research Farm, South Africa. It was been found that production systems that include rotations with medics and/or medic-clover show some potential for improvement compared with wheat only, with a combination of the annual legume pasture with an added saltbush pasture showing the greatest improvement when taking into consideration the benefits from livestock production that are derived from pastures. Pastures are more resilient to changes in rainfall compared with wheat only. Planting pastures in alternate years also improves the yields from wheat, and this is beneficial in periods of low rainfall. Rotation systems on this farm that include lupin perform worse than the wheat-only model. Furthermore, when modelling the effect of drought on the system, the results of the multi-and rotation production systems actually improve.
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There is considerable debate in the literature over whether or not to legalise the trade in rhino... more There is considerable debate in the literature over whether or not to legalise the trade in rhino horns. Here a system dynamics model is developed that considers five components: rhino abundance, rhino demand, a price model, an income model and a supply model. The study indicates the importance of shifting from a conventional (sectoral) conservation model to a more non-conventional (sustainable) approach that models the interactions between the different components. While the results under the no trade scenario are similar for both the equilibrium and disequilibrium model, under the trade scenario results were sometimes quite disparate. This study finds that sometimes second best solutions from an economic perspective may be optimal if conservation interests are to be achieved.
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Impact Assessment and Project Appraisal, 2002
... Tree Publishing, 10 Watford Close, Guildford, Surrey GU1 2EP, UK Economic valuation in EA Env... more ... Tree Publishing, 10 Watford Close, Guildford, Surrey GU1 2EP, UK Economic valuation in EA Environmental economic valuation and its application in environmental assessment: an evaluation of the status quo with reference to South Africa Douglas Crookes and Martin de Wit ...
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ABSTRACT a b s t r a c t Investing in urban natural assets can leverage relatively high economic ... more ABSTRACT a b s t r a c t Investing in urban natural assets can leverage relatively high economic value in city economies. It is not only the case for highly developed cities, but could also be the case for rapidly developing cities. This is the key message from a case study for the City of Cape Town in South Africa as presented in this paper. It was calculated that the leverage of municipal expenditure on maintaining and enhancing ecosystems is 1.2–2 times higher than the leverage of all municipal expenditure on the City economy. Investing and maintaining a City's natural assets or ecological infrastructure yields economically valuable services that could prove to be an important driver of value addition in a city's economy. It is conservatively estimated that for the City of Cape Town, natural assets yield a flow of ecosystem services valued in the order of R4 billion per annum, within a range between R2 billion and R6 billion per annum. Most of this value for the City of Cape Town is created through the tourism industry, but recreation in parks, open spaces and beaches, as well as specific industries such as film-making, also benefit substantially from the services provided by well-functioning ecosystems. Buffering services to better cope with natural hazards such as coastal surges, flooding and fires in urban contexts are important services from an insurance perspective. As entities focused on service provision and as enablers of economic growth and development, municipalities in rapidly developing urban centrums have the mandate and must create the opportunity to invest adequately in natural assets to maintain a healthy flow of ecosystem services to the benefit of people living in and visiting their cities. & 2012 Published by Elsevier B.V.
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Journal of Environmental Assessment Policy and Management, 2009
Cumulative effects assessments have been defined as environmental assessments done well. However,... more Cumulative effects assessments have been defined as environmental assessments done well. However, socioeconomic studies within the EIA process seldom adequately address cumulative effects. One of the reasons for this is that the socioeconomic tools used in the EIA process have not been evaluated and, where necessary, updated to address cumulative effects. This article evaluates current and potential tools, from a
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Publications by D. Crookes
Papers by D. Crookes