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Academic Staff

Res Altwegg

Office: PD Hahn 6.72
Tel: +27 21 650 5750

Research Interests: Statistical Ecology; Wildlife Demography

Position: Associate Professor

Courses Taught

  • STA1007S – Bionumeracy
  • STA2007F – Applied Statistical Modelling

Research Interests

My interests lie at the intersection between statistics, ecology and conservation biology. Decision making in conservation often depends on observational data sets where key processes cannot be observed directly. We are estimating wildlife demography from capture-mark-recapture data using models that explicitly account for the observation process. For threatened species, the data are often sparse and we integrate information from different data types using integrated population models. Current projects focus on the declining African penguin and the rare but increasing peregrine falcon, among many other species. We are developing methods for analysing large-scale bird atlas data where uneven sampling and a heterogeneous detection process are key features. This work is based on dynamic occupancy models with spatially correlated random effects. To estimate densities of cryptic species, we develop spatially explicit capture-recapture models for analysing acoustic data collected on microphone arrays. This method is currently being tested on endangered moss frogs in collaboration with CapeNature. Particularly challenging are biodiversity data where presence of species are opportunistically recorded. We are developing geostatistical methods to interpolate species distributions from such data and are currently testing the methods on the data collected for the national butterfly conservation assessment.


  • 73. Salguero-Gómez, R., O.R. Jones, C.R. Archer, Y.M. Buckley, J. Che-Castaldo, H. Caswell, A. Scheuerlein, D.A. Conde, A. Baudisch, E. Brinks, H. de Buhr, C. Farack, F. Gottschalk, A. Hartmann, A. Henning, G. Hoppe, G. Römer, J. Runge, T. Ruoff, J. Wille, S. Zeh, D. Vieregg, R. Altwegg, F. Colchero, M. Dong, D. Hodgson, H. de Kroon, J.-D. Lebreton, C.J.E. Metcalf, M. Neel, I. Parker, T. Takada, T. Valverde, L.A. Vélez-Espino, G.M. Wardle, M. Franco, and J.W. Vaupel. 2014. The COMPADRE Plant Matrix Database: an Open Online Repository for Plant Demography. Journal of Ecology: in press.
  • 72. Péron, G., and R. Altwegg. The abundant centre syndrome and species distributions: insights from closely related species pairs in southern Africa. Global Ecology and Biogeography. In press.
  • 71. Collingham, Y, B. Huntley, R. Altwegg, P. Barnard, O.S. Beveridge, R.D. Gregory, L.R. Mason, H.D. Oschadleus, R.E. Simmons, S.G. Willis, R.E. Green. 2014. Prediction of mean adult survival rates of southern African birds from demographic and ecological covariates. Ibis 156: 741-754. doi: 10.1111/ibi.12195
  • 70. Sherley, R.B, F. Abadi, K. Ludynia, B.J. Barham, A.E. Clark, and R. Altwegg. 2014. Age-specific survival and movement among major African Penguin Spheniscus demersus colonies. Ibis 156: 716-728. doi: 10.1111/ibi.12189
  • 69. Duckworth, G.D. and R. Altwegg. 2014. Environmental drivers of an urban hadeda ibis population. Ardea 102: 21-29.
  • 68. Lloyd, P., F. Abadi, R. Altwegg, and T.E. Martin. 2014. South temperate birds have higher apparent adult survival than tropical birds in Africa. Journal of Avian Biology 45: 493-500. doi: 10.1111/jav.00454
  • 67. Weller, F., L.-A. Cecchini, L. Shannon, R.B. Sherley, R.J.M. Crawford, R. Altwegg, L. Scott, T. Stewart, and A. Jarre. 2014. A system dynamics approach to modelling multiple drivers of the African penguin population on Robben Island, South Africa. Ecological Modelling 277: 38-56.
  • 66. Jansen, D.Y.M., F. Abadi, D. Harebottle, and R. Altwegg. 2014. Does seasonality drive spatial patterns in demography? Variation in survival in African Reed Warblers Acrocephalus baeticatus across southern Africa does not reflect global patterns. Ecology and Evolution 4: 889-898.
  • 65. Broms, K.M., D.S. Johnson, R. Altwegg, and L.L. Conquest. 2014. Spatial occupancy models applied to atlas data show southern ground hornbills strongly depend on protected areas. Ecological Applications 24: 363-374.
  • 64. Emaresi, G., P. Bize, R. Altwegg, I. Henry, V. van den Brink, J. Gasparini, and A. Roulin. 2014. Melanin-specific life history strategies. American Naturalist 183: 269-280.
  • 63. Altwegg, R., C. Doutrelant, M.D. Anderson, C.N. Spottiswoode, and R. Covas. 2014. Climate, social factors and research disturbance influence population dynamics in declining sociable weaver metapopulation. Oecologia 174: 413-425. DOI: 10.1007/s00442-013-2768-7
  • 62. Altwegg, R., A. Jenkins, and F. Abadi. 2014. Nest boxes and immigration drive growth of an urban Peregrine Falcon population. Ibis 156: 107-115.
  • 61. Bled, F., J.D. Nichols, and R. Altwegg. 2013. Dynamic occupancy models for analysing species' range dynamics across large geographic scales. Ecology and Evolution 3: 4896-4909. DOI: 10.1002/ece3.858
  • 60. Wheeler, M., M.S. de Villiers, and R. Altwegg. 2013. Effect of human disturbance on the behavioural responses and offspring survival of grey-headed albatrosses Thalassarche chrysostoma at Subantarctic Marion Island. African Journal of Marine Science 35: 533-543.
  • 59. Chambers, L.E., R. Altwegg, C. Barbraud, P. Barnard, L. Beaumont, R.J.M Crawford, J.M. Durant, L. Hughes, M.R. Keatley, M. Low, L.P.C. Morellato, E. Poloczanska, V Ruoppolo, R.E.T. Vanstreels, E.J. Woehler, A.C. Wolfaardt. 2013. Phenological changes in the Southern Hemisphere. PlosOne 8: e75514.
  • 58. Sæther, B.-E., T. Coulson, V. Grøtan, S. Engen, R. Altwegg, K.B. Armitage, C. Barbraud, P.H. Becker, D.T. Blumstein, F.S. Dobson, M. Festa-Bianchet, J.-M. Gaillard, A. Jenkins, C. Jones, M.A.C. Nicoll, K. Norris, M.K. Oli, A. Ozgul, and H. Weimerskirch. 2013. How life history influences population dynamics in fluctuating environments. American Naturalist 182: 743-759.
  • 57. Katz, E.M., K.A. Tolley, and R. Altwegg. 2013. Survival and abundance of Cape Dwarf Chameleons, Bradypodion pumilum, inhabiting a transformed, semi-urban wetland. Herpetological Journal 23: 179-186.
  • 56. Abadi, F., A. Botha, and R. Altwegg. 2013. Revisiting the effect of capture heterogeneity on survival estimates in capture-mark-recapture studies: does it matter? PlosOne 8: e62636.
  • 55. Erni, B., B.T. Bonnevie, H.D. Oschadleus, R. Altwegg, and L. Underhill. 2013. moult: An R Package to Analyze Moult in Birds. Journal of Statistical Software 52: 8.
  • 54. Altwegg, R., Y. Collingham, B. Erni, and B. Huntley. 2013. Density-dependent dispersal and the speed of range expansions. Diversity and Distributions 19: 60-68.
  • 53. Distiller, G., R. Altwegg, R.J.M. Crawford, N.T.W. Klages, and B. Barham. 2012. Factors affecting adult survival and inter-colony movement at the three South African colonies of Cape gannet. Marine Ecology Progress Series 461: 245-255.
  • 52. Braby, J, S.J Braby, R.J Braby, and R. Altwegg. 2012. Annual dispersal and survival of a seabird adapted to a stable environment: implications for conservation. Journal of Ornithology 153: 809-816. DOI: 10.1007/s10336-011-0798-7
  • 51. Altwegg, R., K. Broms, B. Erni, P. Barnard, G.F. Midgley, and L.G. Underhill. 2012. Novel methods reveal shifts in migration phenology of barn swallows in South Africa. Proceedings of the Royal Society of London B 279: 1485-1490. DOI:10.1098/rspb.2011.1897
  • 50. Duckworth, G.D., R. Altwegg, and D.M. Harebottle. 2012. Demography and population ecology of the Hadeda Ibis (Bostrychia hagedash) at its expanding range edge in South Africa. Journal of Ornithology 153: 421-430. DOI: 10.1007/s10336-011-0758-2
  • 49. Huntley, B., P. Barnard, R. Altwegg, Y.C. Collingham, and D.G. Hole. 2012. Modelling relationships between species spatial abundance patterns and climate. Global Ecology and Biogeography 21: 668-681. DOI: 10.1111/j.1466-8238.2011.00701.x
  • 48. Braby, J., S.J. Braby, R.J. Braby, and R. Altwegg. 2011. Immature survival and age at first breeding of Damara Terns: conservation from a non-breeding perspective. Ardea 99: 185 -190.
  • 347. Crawford, R.J.M., R. Altwegg, B.J. Barham, P.J. Barham, J.M. Durant, B.M. Dyer, D. Geldenhuys, A.B. Makhado, L. Pichegru, P.G. Ryan, L.G. Underhill, L. Upfold, J. Visagie, L.J. Waller, and P.A. Whittington. 2011. Collapse of South Africas penguins in the early 21st century. African Journal of Marine Science 33: 139-156.
  • 46. Joseph, G.S., G.S. Cumming, D.H.M. Cumming, Z. Mahlangu, R. Altwegg, and C.L. Seymour. 2011. Large termitaria act as refugia for tall trees, deadwood and cavity-using birds in a miombo woodland. Landscape Ecology 26: 439-448.
  • 45. Duckworth, G., R. Altwegg, and D. Guo. 2010. Soil moisture limits foraging: a possible mechanism for the range dynamics of hadeda ibis in Southern Africa. Diversity and Distributions 16: 765-772.
  • 44. Simmons, R.E., and R. Altwegg. 2010. Necks-for-sex or competing browsers? A critique of ideas on the evolution of giraffe. Journal of Zoology 282: 6-12.
  • 43. Tolley, K.A., R.N.V. Raw, R. Altwegg, and G.J. Measey. 2010. Chameleons on the move: survival and migration of the Cape dwarf chameleon, Bradypodion pumilum, within a fragmented semi-urban habitat. African Zoology 45: 99-106.
  • 42. Roulin, A., R. Altwegg, H. Jensen, I. Steinsland, and M. Schaub. 2010. Sex-dependent selection on an autosomal melanic female ornament promotes the evolution of sex ratio bias. Ecology Letters 13: 616-626.
  • 41. Midgley, G.F., I.D. Davies, W. Thuiller, C.H. Albert, R. Altwegg, L. Hannah, G.O. Hughes, L.R. O’Halloran, C. Seo, J.H. Thorne. 2010. BioMove an integrated platform simulating the dynamic response of species to environmental change. Ecography 33: 612-616.
  • 40. Huntley, B., P. Barnard, R. Altwegg, L. Chambers, B.W.T. Coetzee, L. Gibson, P.A.R. Hockey, D.G. Hole, G.F. Midgley, L.G. Underhill, and S.G. Willis. 2010. Beyond bioclimatic envelopes: Dynamic species range and abundance modelling in the context of climatic change. Ecography 33: 621-626.
  • 39. Crawford, R.J.M, and R. Altwegg. 2009. Seabirds and climate change in southern African some considerations. pp. 1-5. In: Harebottle, D.M., Craig, A.J.F.K., Anderson, M.D., Rakotomanana, H. and Muchai, M. (eds). Proceedings of the 12th Pan-African Ornithological Congress, 2008. Cape Town, Animal Demography Unit. ISBN 978-0-7992-2361-3.
  • 38. Crawford, R.J.M, L.G Underhill, R. Altwegg, B.M. Dyer, and L. Upfold. 2009. Trends in numbers of Kelp Gulls Larus dominicanus off western South Africa, 1978-2007. Ostrich 80: 139 – 143.
  • 37. Wanless, R.M., P.G. Ryan, R. Altwegg, A. Angel, J. Cooper, R.J. Cuthbert, and G.M. Hilton. 2009. From both sides: dire demographic consequences of carnivorous mice and longlining for the critically endangered Tristan albatrosses on Gough Island. Biological Conservation 142: 1710-1718.
  • 36. Altwegg, R., and M. Anderson. 2009. Rainfall in arid zones: possible effects of climate change on the population ecology of blue cranes. Functional Ecology 23: 1014 – 1021.
  • 35. Wolfaardt, A.C., L.G. Underhill, R. Altwegg, and J. Visagie. 2008. Restoration of oiled African Penguins Spheniscus demersus a decade after the Apollo Sea spill. African Journal of Marine Science 30: 421-436.
  • 34. Wolfaardt, A.C., L.G. Underhill, R. Altwegg, J. Visagie, and A.J. Williams. 2008. Impact of the Treasure oil spill on African Penguins, at Dassen Island: case study of a rescue operation. African Journal of Marine Science 30: 405-419.
  • 33. Altwegg, R., R.J.M Crawford, L.G. Underhill, and A.J. Williams. 2008. Long term survival of de-oiled Cape Gannets Morus capensis after the Castillo de Belver oil spill of 1983. Biological Conservation 141: 1924-1929.
  • 32. Altwegg, R., M. Wheeler, and B. Erni. 2008. Climate and the range dynamics of species with imperfect detection. Biology Letters 4: 581-584.
  • 31. Barham, P.J., L.G. Underhill, R.J.M. Crawford, R. Altwegg, T. M. Leshoro, B.M. Dyer, and L. Upfold. 2008. The efficacy of hand-rearing penguin chicks: evidence from African Penguins (Spheniscus demersus) orphaned in the Treasure oil spill in 2000. Bird Conservation International 18: 144-152.
  • 30. Duquette, S.L., R. Altwegg, and B.R. Anholt. 2007. Protozoan functional responses: effects of species, genotype and antipredator defences. Evolutionary Ecology Research 9: 789-800.
  • 29. Erni, B., R. Altwegg, and L.G. Underhill. 2007. An index to compare geographical distributions of species. Diversity and Distributions 13: 829-835.
  • 28. Roulin, A. and R. Altwegg. 2007. Breeding rate is associated with pheomelanism in male and with eumelanism in female barn owls. Behavioral Ecology 18: 563-570.
  • 27. Altwegg, R., R.J.M Crawford, A.P. Martin, P.A. Whittington, L.G. Underhill. 2007. Geographic variation in reproduction and survival of kelp gulls Larus dominicanus vetula in southern Africa. Journal of Avian Biology: 38: 580-586.
  • 26. Altwegg, R., M. Schaub, and A. Roulin. 2007. Age-specific fitness components and their temporal variation in the barn owl. American Naturalist 169: 47-61.
  • 25. Bize, P., A. Klopfenstein, J. Gasparini, R. Altwegg, and A. Roulin. 2006. Melanin-based coloration is a non-directionally selected sex-specific signal of offspring development in the Alpine swift. Evolution 60: 2370-2380.
  • 24. Altwegg, R., and L.G. Underhill. 2006. Apparent survival rates of Cape Sugarbirds Promerops cafer at a breeding and a non-breeding site. Ostrich 77: 220-224.
  • 23. Altwegg, R., A. Roulin, M. Kestenholz, and L. Jenni. 2006. Demographic effects of extreme winter weather in the barn owl. Oecologia 149: 44-51.
  • 22. Altwegg, R., M. Eng, S. Caspersen, B.R. Anholt. 2006. Functional response and prey defense level in an experimental predator-prey system. Evolutionary Ecology Research 8: 115-128.
  • 21. Govindarajulu, P., R. Altwegg, B.R. Anholt. 2005. Matrix model investigation of invasive species control: bullfrogs on Vancouver Island. Ecological Applications 15: 2161-2170.
  • 20. Duquette, S.L., R. Altwegg, and B.R. Anholt. 2005. Factors affecting the expression of inducible defences in Euplotes: genotype, predator density, and experience. Functional Ecology 19: 648-655.
  • 19. Sæther, B.-E., R. Lande, S. Engen, H. Weimerskirch, M. Lillegaard, R. Altwegg, P.H. Becker, T. Bregnballe, J.E. Brommer, R. McCleery, J. Merila. Nyholm, W. Rendell, R.R. Robertson, P. Tryjanowski, and M.E. Visser. 2005. Generation time and temporal scaling of bird population dynamics. Nature 436: 99-102.
  • 18. Altwegg, R., S. Dummermuth, B.R. Anholt, and T. Flatt. 2005. Winter weather affects asp viper Vipera aspis population dynamics through susceptible juveniles. Oikos 110: 55-66.
  • 17. Reyer, H.-U., M.-O. Waelti, I. Baettig, R. Altwegg, and B. Hellriegel. 2004. Low proportions of reproducing hemiclonal females increase the stability of a sexual parasite-host system (Rana esculenta, R. lessonae). Journal of Animal Ecology 73: 1089-1101.
  • 16. Altwegg, R., K.B. Marchinko, S.L. Duquette, and B.R. Anholt. 2004. Dynamics of an inducible defence in the protist Euplotes. Archiv fuer Hydrobiologie 160: 431-446.
  • 15. Salewski, V., R. Altwegg, B. Erni, K.H. Falk, F. Bairlein, and B. Leisler. 2004. Moult of three Palearctic migrants in their West African winter quarters. Journal fuer Ornithologie 145: 109-116.
  • 14. Blanckenhorn, W.U., B. Hellriegel, D.J. Hosken, P. Jann, R. Altwegg, and P.I. Ward. 2004. Does testis size track expected mating success in yellow dung flies? Functional Ecology 18: 414-418.
  • 13. Altwegg, R. 2003. Multi-stage density dependence in an amphibian. Oecologia 136: 46-50.
  • 12. Roulin, A., B. Ducret, P.-A. Ravussin, and R. Altwegg. 2003. Female plumage coloration covaries with reproductive strategies in the tawny owl. Journal of Avian Biology 34: 393-401.
  • 11. Altwegg, R., A. Roulin, M. Kestenholz, and L. Jenni. 2003. Variation and covariation in survival, dispersal, and population size in barn owls (Tyto alba). Journal of Animal Ecology 72: 391-399.
  • 10. Altwegg, R., and H.-U. Reyer. 2003. Patterns of natural selection on size at metamorphosis in water frogs. Evolution 57: 872-882.
  • 9. Altwegg, R. 2003. Hungry predators render predator avoidance behavior in tadpoles ineffective. Oikos 100: 311-316.
  • 8. Salewski, V., R. Altwegg, F. Liechti, and D. Peter. 2003. New records of Moussier’s redstart Phoenicurus moussieri and lesser striped swallow Hirundo abyssinica from Mauritania. Malimbus 25: 103-104.
  • 7. Salewski, V., R. Altwegg, A. Ba, F. Liechti, and D. Peter. 2002. Body mass and fat scores of Palaearctic migrants at the southern fringe of the Sahara desert in autumn. Vogelwarte 41: 291-294.
  • 6. Altwegg, R. 2002. Predator induced life-history plasticity under time constraints in pool frogs. Ecology 83: 2542-2551.
  • 5. Altwegg, R. 2002. Trait-mediated indirect effects and complex life cycles in two European frogs. Evolutionary Ecology Research 4: 519-536.
  • 4. McElligott, A.G., R. Altwegg, and T.J. Hayden. 2002. Age-specific survival and reproductive probabilities: evidence for senescence in male fallow deer (Dama dama). Proceedings of the Royal Society of London B 269: 1129-1137.
  • 3. Altwegg, R., T.H. Ringsby, and B.-E. Sæther. 2000. Phenotypic correlates and consequences of dispersal in a metapopulation of house sparrows Passer domesticus. Journal of Animal Ecology 69: 762-770.
  • 2. Solberg, E.J., T.H. Ringsby, R. Altwegg, and B.-E. Sæther. 2000. Fertile House Sparrow X Tree Sparrow (Passer domesticus X Passer montanus) hybrids? Journal fuer Ornithologie 141: 102-104.
  • 1. Ringsby, T.H., B.-E. Sæther, R. Altwegg, and E.J. Solberg. 1999. Temporal and spatial variation in survival rates of a house sparrow, Passer domesticus, metapopulation. Oikos 85: 419-425.