Willem De Lange

Dr. Willem De Lange

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Research Focus & Metrics

Academic Career Length

24Years (2003-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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10 September 2008 in PLOS ONE
Verified
Journal Article
Open access
PDF file
MAMike H. Allsopp
Mike H. Allsopp
Willem De LangeWillem De Lange
Willem De Lange
Ruan VeldtmanRuan Veldtman
Ruan Veldtman
Value estimates of ecosystem goods and services are useful to justify the allocation of resources towards conservation, but inconclusive estimates risk unsustainable resource allocations. Here we present replacement costs as a more accurate value estimate of insect pollination as an ecosystem service, although this method could also be applied to other services. The importance of insect pollination to agriculture is unequivocal. However, whether this service is largely provided by wild pollinators (genuine ecosystem service) or managed pollinators (commercial service), and which of these requires immediate action amidst reports of pollinator decline, remains contested. If crop pollination is used to argue for biodiversity conservation, clear distinction should be made between values of managed- and wild pollination services. Current methods either under-estimate or over-estimate the pollination service value, and make use of criticised general insect and managed pollinator dependence factors. We apply the theoretical concept of ascribing a value to a service by calculating the cost to replace it, as a novel way of valuing wild and managed pollination services. Adjusted insect and managed pollinator dependence factors were used to estimate the cost of replacing insect- and managed pollination services for the Western Cape deciduous fruit industry of South Africa. Using pollen dusting and hand pollination as suitable replacements, we value pollination services significantly higher than current market prices for commercial pollination, although lower than traditional proportional estimates. The complexity associated with inclusive value estimation of pollination services required several defendable assumptions, but made estimates more inclusive than previous attempts. Consequently this study provides the basis for continued improvement in context specific pollination service value estimates.


15 June 2010 in Landscape Ecology
Verified
Journal Article
Closed access
PDF file
POP. J. O’fArrell
P. J. O’fArrell
BRB. Reyers
B. Reyers
DMD. C. Le Maitre
D. C. Le Maitre
SMS. J. Milton
S. J. Milton
BEB. Egoh
B. Egoh
RCR. M. Cowling
R. M. Cowling

1 November 2012 in Waste Management
Verified
Journal Article
Closed access
ANAnton Nahman
Anton Nahman
Willem De LangeWillem De Lange
Willem De Lange
SOSuzan Oelofse
Suzan Oelofse
LGLinda Godfrey
Linda Godfrey

1 November 2013 in Waste Management
Verified
Journal Article
Closed access
ANAnton Nahman
Anton Nahman
Willem De LangeWillem De Lange
Willem De Lange

1 July 2020 in Renewable Energy
Verified
Journal Article
Closed access
WSW. Stafford
W. Stafford
Willem De LangeWillem De Lange
Willem De Lange
ANA. Nahman
A. Nahman
VCV. Chunilall
V. Chunilall
PLP. Lekha
P. Lekha
DTD. Trotter
D. Trotter