Konrad Wessels is currently a Chief Scientist and Research Group Leader for the Remote Sensing Research Unit of the CSIR-Meraka Institute, Pretoria, South Africa. He is an extraordinary senior lecturer with the University of Pretoria, Department of Geography, Geoinformatics and Meteorology. He was awarded a NASA Earth System Sciences fellowship and completed his PhD in Geography (now Geographical Sciences) at the University of Maryland.

He has a background in ecology and environmental sciences and specializes in environmental earth observation. Research interest include, land cover change, savanna ecology, fire, communal resource management, carbon cycle and biomass estimation.

QUALIFICATIONS

BSc,  (Pretoria),  BSc Honours (Pretoria), MSc (Pretoria) PhD Geography (University of Maryland, USA)

TEACHING

GMA705 Advanced Remote Sensing Techniques (guest lecturer)

RECENT PROJECTS (selected)

• Impact of fire, elephants and communal fuelwood extraction on woody vegetation in and around Kruger National Park.

Co-PI on collaborative research project with Dr. Greg Asner of Carnegie Institute for Science’s (Carnegie Airborne Observatory – CAO, integrated Lidar and hyperspectral system). The project tackled fundamental questions related to remote sensing of vegetation structure (Lidar, SAR) and savanna ecology.

• Application development in support of South African Earth Observation Strategy

This large project funded the development of diverse earth observation application of national interest (funded by National Department of Science and Technology - DST). Applications focused on fire information, land cover change detection, woody vegetation monitoring, time series analysis and on-line viewers.

• Southern African Science Service Centre for Climate Change and Adaptive Land Management (SASSCAL)

Our work package focuses on mapping woody vegetation cover and biomass in South Africa, Zambia and Namibia with Lidar and SAR data. (Funded by German Federal Ministry for Education and Research)

• Modelling national Carbon Stocks and Fluxes

The project implemented models to map above and below ground carbon stock and major fluxes using climate data and satellite data. The outputs formed the basis of national carbon budget.

https://www.environment.gov.za/sites/default/files/reports/nationalterrestrial_carbonsinks_synopsisreport.pdf

• User requirements analysis for  forestry and land cover applications with EOSAT1

The project systematically analyzed needs, information products, algorithms, measurements and sensors required from South Africa’s third planned earth observation satellite (EOSAT1)

• Multi-scale change detection and land cover mapping

R&D project on rapid land cover updates using change detection and machine learning. Human settlement classification and change detection using textural features and very high resolution imagery. (co-funded by SA’s mapping agency – National Geospatial Information – NGI) 

PEER-REVIEWED JOURNAL PAPERS (selected) 

• Fisher, J., Erasmus, B., Witkowski, E., Van Aardt, J., Asner, G., Wessels, K., & Mathieu, R. (2014). Management approaches of conservation areas: Differences in woody vegetation structure in a private and a national reserve. South African Journal of Botany, 90, 146-152
• Fisher, J.T., Erasmus, B.F., Witkowski, E.T., Aardt, J., Wessels, K.J., & Asner, G.P. (2014). Savanna woody vegetation classification–now in 3‐D. Applied Vegetation Science, 17, 172-184
• Fisher, J.T., Witkowski, E.T., Erasmus, B.F., Mograbi, P.J., Asner, G.P., Aardt, J.A., Wessels, K.J., & Mathieu, R. (2015). What lies beneath: detecting sub‐canopy changes in savanna woodlands using a three‐dimensional classification method. Applied Vegetation Science
• Kleynhans, W., Salmon, B., Wessels, K., & Olivier, J. (2015). Rapid detection of new and expanding human settlements in the Limpopo province of South Africa using a spatio-temporal change detection method. International Journal of Applied Earth Observation and Geoinformation, 40, 74-80
• McGlinchy, J., van Aardt, J., Erasmus, B., Asner, G.P., Mathieu, R., Wessels, K., Knapp, D., Kennedy-Bowdoin, T., Rhody, H., & Kerekes, J.P. (2014). Extracting structural vegetation components from small-footprint waveform LiDAR for biomass estimation in savanna ecosystems. Selected Topics in Applied Earth Observations and Remote Sensing, IEEE Journal of, 7, 480-490
• Mograbi, P.J., Erasmus, B.F., Witkowski, E., Asner, G.P., Wessels, K.J., Mathieu, R., Knapp, D.E., Martin, R.E., & Main, R. (2015). Biomass Increases Go under Cover: Woody Vegetation Dynamics in South African Rangelands. PLOS One, DOI:10.1371/journal.pone.0127093
• Naidoo, L., Mathieu, R., Main, R., Kleynhans, W., Wessels, K., Asner, G., & Leblon, B. (2015). Savannah woody structure modelling and mapping using multi-frequency (X-, C-and L-band) Synthetic Aperture Radar data. ISPRS Journal of Photogrammetry and Remote Sensing, 105, 234-250
• Salmon, B.P., Kleynhans, W., van den Bergh, F., Olivier, J.C., Grobler, T.L., & Wessels, K.J. (2013). Land cover change detection using the internal covariance matrix of the extended Kalman filter over multiple spectral bands. Selected Topics in Applied Earth Observations and Remote Sensing, IEEE Journal of, 6, 1079-1085
• Tsela, P., Wessels, K., Botai, J., Archibald, S., Swanepoel, D., Steenkamp, K., & Frost, P. (2014). Validation of the two standard MODIS satellite burned-area products and an empirically-derived merged product in South Africa. Remote Sensing, 6, 1275-1293
• Cho, M.A., Mathieu, R., Asner, G.P., Naidoo, L., van Aardt, J., Ramoelo, A., Debba, P., Wessels, K., Main, R., & Smit, I.P. (2012). Mapping tree species composition in South African savannas using an integrated airborne spectral and LiDAR system. Remote Sensing of Environment, 125, 214-226
• Mathieu, R., Naidoo, L., Cho, M.A., Leblon, B., Main, R., Wessels, K., Asner, G.P., Buckley, J., Van Aardt, J., & Erasmus, B.F. (2013). Toward structural assessment of semi-arid African savannahs and woodlands: The potential of multi-temporal polarimetric RADARSAT-2 fine beam images. Remote Sensing of Environment, 138, 215-231 
• Wessels K.J. et al. 2013 Unsustainable fuelwood extraction from South African savannas  Environmental Research Letters 8: 014007
• Wessel, K.J., Van Den Bergh F., Scholes R.J. (2012) Limits to detectability of land degradation by trend analysis of vegetation index data. Remote Sensing of Environment. 125: 10-22
• Fensholt, R. et al., Wessels K.J. (2012) Greenness in semi-arid areas across the globe 1981-2007 - an Earth Observing Satellite based analysis of trends and drivers. Remote Sensing of Environment, 121, 144-158
• J. T.  Fisher J.T., E.T.F. Witkowski,  B.F.N.  Erasmus,  J . vanAardt ,  G. P.   Asner,  K. J.  Wessels, R.  Mathieu (2011) Human-modified landscapes: patterns of fine-scale woody vegetation structure in communal savannah rangelands. Environmental Conservation 39 (1): 72–82
• Salmon BP; Olivier JC; Kleynhans W; Wessels KJ; Van den Bergh F; Steenkamp KC (2011) The use of a multilayer perceptron for detecting new human settlements from a time series of MODIS images. International Journal of Applied Earth Observation and Geoinformation, 13:  873-883
• Wessels K.J., Mathieu R., Erasmus B.F.N.,  Asner G.P., Smit I.P.J., van Aardt J.A.N., Main R., Fisher J., Marais W., Kennedy-Bowdoin T., Knapp D.E., Emerson R., Jacobson J. (2011) Impact of communal land use and conservation on woody vegetation structure in the Lowveld savannas of South Africa. Forest Ecology and Management. 261: 19-29
• Wessels K., Steenkamp K., von Maltitz G., Archibald S. (2011) Remotely-sensed vegetation phenology for describing and predicting the biomes of South Africa. Applied Vegetation Science, 14: 49-66.
• Salmon B.P., J.C. Olivier, K.J. Wessels, W. Kleynhans, F. van den Bergh, and K. C. Steenkamp (2010) Unsupervised land cover change detection: Meaningful Sequential Time Series Analysis. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. 4: 327-335
• Wessels. K.J. (2009) Comments on ‘Proxy global assessment of land degradation’ by Bai et al. (2008) Soil Use and Management, March 2009, 25, 91–92.
• Van Den Bergh F., Wessels K.J. et al. (2011) HiTempo: a platform for time-series analysis of remote sensing satellite data in a high performance computing environment. International Journal of Remote Sensing – Time series analysis special issue: 33: 4720–4740
• Kleynhans, W., J.C. Olivier, K.J. Wessels, F. van den Bergh, B.P. Salmon (in press, on–line) Detecting Land Cover Change Using an Extended Kalman Filter on MODIS NDVI Time-Series Data, IEEE Geoscience And Remote Sensing Letters, VOL. 8, NO. 3, MAY 2011 (IEEE Early access) Doi: 10.1109/LGRS.2010.2089495
• Kleynhans, W.,  J.C. Olivier, K.J. Wessels, F. van den Bergh, B.P. Salmon and K. Steenkamp (2010) Improving Land Cover Class Separation using an Extended Kalman Filter on MODIS NDVI Time Series Data. IEEE GeoScience and Remote Sensing Letters. 7(2) 381-385
• Wessels, K.J., Prince, S.D., and Reshef, I. (2008) Mapping land degradation by comparison of vegetation production to spatially-derived estimates of potential production. Journal of Arid Environments. 72, 1940-1949.
• Wessel K.J., Prince S.D., M. Carroll and J. Malherbe (2007) Relevance of rangeland degradation in semi-arid Northeastern South Africa to the non-equilibrium theory. Ecological Applications. 17, 815-827
• Prince S.D., Wessels K.J., Tucker C.J. and Nicholson S.E. (2007) Desertification in the Sahel: a reinterpretation of a reinterpretation. Global Change Biology.13, 1308-1313.
• Wessels K.J., Prince S.D., Malherebe J., Small J. and P.E. Frost (2007) Can human-induced land degradation be distinguished from the effects of rainfall variability? A case study in South Africa. Journal of Arid Environments, 68, 271-297.
• Wessels K.J., Prince S.D., Zambatis N., Macfadyen S., Frost P.E. and D. VanZyl (2006) Relationship between herbaceous biomass and 1km² Advanced Very High Resolution Radiometer (AVHRR) NDVI in Kruger National Park, South Africa. International Journal of Remote Sensing, 27, 951-973.
• Wessels K.J., S.D. Prince, Frost P.E., van Zyl D. (2004) Assessing the effects of human-induced land degradation in the former homelands of northern South Africa with a 1km AVHRR NDVI time-series. Remote Sensing of Environment, 91, 47-67.
• Wessels K.J., DeFries, R., Anderson L.O., Hansen A.J., Powell, S.L. and Moran E.F. (2004) Mapping regional land cover with MODIS data for biological conservation: Examples from the Greater Yellowstone Ecosystem, USA and Pará State, Brazil. Remote Sensing of Environment 92, 67-83.
• Wessels K.J., Reyers B., Van Jaarsveld A.S. and Rutherford M.C. (2003) Identification of potential conflict areas between land transformation and biodiversity conservation in north-eastern South Africa. Agriculture, Ecosystems and Environment 95, 157-178.
• Wessels K.J., Freitag S. and Van Jaarsveld A.S. (1999) The use of Land Facets as Biodiversity Surrogates during reserve selection at a Local Scale. Biological Conservation 89, 21-38.
• Wessels K.J., Grimbeek J.D., Van Der Linde M.J. and Van Jaarsveld A.S. (1998) An Evaluation of the Gradsect Biological Survey method. Biodiversity and Conservation 7, 1093-1121.