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Photo: Anina Coetzee
Department of Botany and Zoology
Prof. Anton C. Pauw
I am interested in the evolutionary processes that generate biodiversity and the ecological processes that maintain it. These processes span spatial and temporal scales, however, the focus of my interest is the evolutionary-ecology of populations, because key processes seem to operate at this level. I am currently studying plant-pollinator interactions. At the Cape, where many plant species differ only in their floral features, pollinators may hold the key to understanding the genesis of this area's spectacular floral diversity. By studying variation in pollination amongst populations, it is possible to examine the processes which result in floral differentiation and ultimately speciation. From an ecological perspective, pollination is interesting because plant reproduction and population persistence often depends on pollination. Many of the Cape 's famously specialized pollinators, including long-tongued flies, sunbirds and oil-collecting bees are threatened by man's activities. By understanding the role of pollinators in maintaining and generating plant diversity, it might be possible to predict and ameliorate human impacts.
Sunbird Restoration Project
What will the world be like without birds? We know that birds pollinate many plant species, they disperse the seeds of an even greater number; in addition they are predators that prey on innumerable insects every day. Nevertheless, the world without birds is difficult to imagine because so many factors interact in complex ways to shape the natural world around us.
In the Cape region of South Africa, the long-tailed Cape Sugarbird (Promerops cafer) and the iridescent Sunbirds (Nectarinidae), pollinate approximately 400 plant species, including the dominant Protea shrubs, which are a favorite source of nectar . The birds are threatened by habitat fragmentation, urbanization, disease, alien plant invasion and honeybee farming [2-4]. In addition, they are likely to be sensitive to climate change because their abundance is strongly influenced by fires .
All over the world birds and other pollinators are declining in number [6, 7]. One possible outcome is that the human-caused loss of these mutualists will trigger a cascade of linked extinctions [6, 8-13]. On the other hand, pollination is often considered to be of little ecological importance because, in the absence of their primary pollinator, many plants can make seed by self-pollinating or switching to other pollinators [14-16]. Even if seed production fails, little may change, because many plants can reproduce by vegetative propagation, or are simply very long-lived [12, 14].
To answer the question of the ecological significance birds as pollinators we are conducting a bird exclusion experiment on an unprecedented scale. We are simulating the “World without Birds” in five walk-in cages, each of which excludes birds from a 20 X 20 m area of natural Fynbos vegetation in the Cape Mountains. To assess the effect of losing birds we are comparing areas inside the exclosures with adjacent areas outside. We are particularly interested in the effect of bird exclusion on the architecture of plant-pollinator networks and seed production, but because birds also play other roles we are additionally monitoring seed dispersal, insect community composition and leaf damage inside and outside the cages. Additionally the exclosures offer the opportunity to assess the role of birds as vectors of Protea mites, which are themselves important in the transmission of fungal spores and possibly pollen .
After three years of bird exclosure the vegetation in the study area will be burned as part of the normal fire management routine. Fire triggers the regeneration of Fynbos vegetation, but its ability to recover from fire might be compromised by the loss of birds. If the lack of pollination services provided by birds meaningfully reduces seed production, we predict that important plant species will be lost and that the composition of the recovering vegetation will shift from one dominated by bird-pollinated plants to one dominated by insect- and wind-pollinated plants including alien species .
The research component of the project dovetails with a community-based, science outreach project in disadvantaged areas of the Cape Town. We aim to identify young people with a talent for working with biodiversity and guide them to become environmental leaders. We hope to do this by engaging strategically located high schools in a pollinator restoration project with the Sunbirds and Sugarbirds as the focus. The project will guide learners to establish gardens of bird-pollinated plants on school grounds. These gardens will relink broken migration routes for birds by acting as stepping-stones across urban areas. The learners will monitor the progress of restoration by observing flower-visiting birds and reporting the data to the Animal Demography Unit via a cellphone application and website (http://mybirdpatch.adu.org.za). The data will be mapped on Google Earth to monitor the progress of restoration. Interested and talented students can easily be identified because the electronic data capture system will not only collect data on birds but will simultaneously track the progress of the learners as they submit the data. The subset of keen students identified in this way will be invited to participate as field assistants in the bird exclosure study.
The researchers involved in this project are: Prof. Anton Pauw (Stellenbosch University), Dr Phoebe Barnard (South African National Biodiversity Institute), Dr Sjirk Geerts (Cape Peninsula University of Technology), Bongani Mnisi (M.Sc. student and Biodiveristy Manager City of Cape Town), Anina Coetzee (Ph.D. student), Pieter Botha (M.Sc. student) and Adam Van Nieuwenhuizen (Landscape Architect).
News / Links / Resources
Rebelo, A.G. (1987) Bird pollination in the Cape Flora. In A preliminary synthesis of pollination biology in the Cape flora (141 edn) (Rebelo, A.G., ed), pp. 83-108, CSIR
Geerts, S. and Pauw, A. (2011) Farming with native bees (Apis mellifera subsp. capensis Esch.) has varied effects on nectar-feeding bird communities in South African fynbos vegetation. Popul. Ecol. 53, 333-339
Geerts, S. and Pauw, A. (2011) Easy technique for assessing pollination rates in the genus Erica reveals road impact on bird pollination in the Cape fynbos, South Africa. Austral Ecol. 36, 656-662
Geerts, S. and Pauw, A. (2012) The cost of being specialized: Pollinator limitation in the endangered geophyte Brunsvigia litoralis (Amaryllidaceae) in the Cape Floristic Region of South Africa. S. Afr. J. Bot. 78, 159-164
Geerts, S., et al. (2012) Reduced flower visitation by nectar-feeding birds in response to fire in Cape fynbos vegetation, South Africa. Journal of Ornithology 153, 297-301
Anderson, S.H., et al. (2011) Cascading effects of bird functional extinction reduce pollination and plant density. Science 331, 1068-1071
Potts, S.G., et al. (2010) Global pollinator declines: trends, impacts and drivers. Trends Ecol. Evol. 25, 345-353
Fortuna, M.A. and Bascompte, J. (2006) Habitat loss and the structure of plant-animal mutualistic networks. Ecol. Lett. 9, 278-283
Cox, P.A., et al. (1991) Flying foxes as strong interactors in South-Pacific island ecosystems - a conservation hypothesis. Conserv. Biol. 5, 448-454
Gilbert, L.E. (1978) Food web organization and the conservation of neotropical diversity. In Conservation biology: an evolutionary ecological perspective (Soule, M.E. and Wilcox, B.A., eds), pp. 11-34, Sinauer
Memmott, J., et al. (2007) Global warming and the disruption of plant–pollinator interactions. Ecol. Lett. 10, 710–717
Pauw, A. and Bond, W.J. (2011) Mutualisms matter: pollination rate limits the distribution of oil-secreting orchids. Oikos 120, 1531-1538
Pauw, A. and Hawkins, J.A. (2011) Reconstruction of historical pollination rates reveals linked declines of pollinators and plants. Oikos 120, 344-349
Bond, W.J. (1994) Do mutualisms matter - assessing the impact of pollinator and disperser disruption on plant extinction. Philos. Trans. R. Soc. Lond., Ser. B: Biol. Sci. 344, 83-90
Ghazoul, J. (2005) Buzziness as usual? Questioning the global pollination crisis. Trends Ecol. Evol. 20, 367-373
Knight, T.M., et al. (2005) Pollen limitation of plant reproduction: Pattern and process. Annual Review of Ecology Evolution and Systematics 36, 467-497
Roets, F., et al. (2009) Mite-Mediated Hyperphoretic Dispersal of Ophiostoma spp. from the Infructescences of South African Protea spp. Environ. Entomol. 38, 143-152
Pauw, A. (2013) Can pollination niches facilitate plant coexistence? Trends Ecol. Evol. 28, 30-37
Contact me directly: firstname.lastname@example.org
Pauw, A. & Johnson, S. 1999. Table Mountain: a natural history. Fernwood Press, Cape Town.
Johnson, C.M.* & Pauw, A. 2014. Floral divergence in closely related Leucospermum tottum (Proteaceae) varieties pollinated by birds and long-proboscid flies. Evolutionary Ecology, available online. Impact Factor 2.4
Heystek, A.*, Geerts, S., Barnard, P. & Pauw, A. 2014. Pink flower preference insunbirds does not translate into plant fitness differences in a polymorphic Erica species. Evolutionary Ecology, 28: 457-470. Impact Factor 2.4.
Johnson, C.M.* & Pauw, A. 2014. Adaptation for rodent pollination in Leucospermum arenarium (Proteaceae) despite rapid pollen loss during grooming. Annals of Botany, 113: 931-938. Impact Factor 3.5.
Heystek, A*, & Pauw, A. 2014. Does competition for pollinators contribute to structuring Erica communities? Journal of Vegetation Science, 25: 648-656. Impact factor 2.8
Pauw, A. 2012. Pollination by oil-collecting bees (Rediviva: Melittidae). p. 91-99. In: Cape Orchids: a regional monograph of the orchids of the Cape Floristic Region. ed. W.R. Liltved and S.D. Johnson. Sandstone Editions, Cape Town.
Pauw, A. 2012. Can pollination niches facilitate plant coexistence? Trends in Ecology & Evolution. doi: 10.1016/j.tree.2012.07.019
Gibson, M.R., Richardson, D.M. & Pauw, A. 2012. Can floral traits predict an invasive plant's impact on native plant–pollinator communities? Journal of Ecology 100(5): 1216-1223.
Zhang, F., Hui, C. & A. Pauw. 2012. Adaptive Divergence in Darwin's Race. Evolution. doi: 10.1111/j.1558-5646.2012.01796.x
Jeff Ollerton, Stella Watts, Shawn Connerty, Julia Lock, Leah Parker, Ian Wilson, Sheila Schueller, Julieta Nattero, Andrea A. Cocucci, Ido Izhaki, Sjirk Geerts, Anton Pauw and Jane C. Stout. 2012. Pollination ecology of the invasive tree tobacco Nicotiana glauca: comparisons across native and non-native ranges. Journal of Pollination Ecology, 9(12): 85-95.
Gibson, M. R., Pauw, A. & Richardson, D. M. 2013. Competitive interactions between an invasive plant and co-flowering natives for insect visits. Biological Conservation 157: 196–203.
Pauw, A. and K. Louw. 2012. Urbanization drives a reduction in functional diversity in a guild of nectar-feeding birds. Ecology and Society 17 (2): 27.
Geerts, S., Malherbe, S. & Pauw, A. 2012. Reduced flower visitation by nectar-feeding birds in response to fire in Cape fynbos vegetation, South Africa. Journal of Ornithology 153: 297-301.
Geerts, S. & Pauw, A. 2012. The cost of being specialized: Pollinator limitation in the endangered geophyte Brunsvigia litoralis (Amaryllidaceae) in the Cape Floristic Region of South Africa. S. Afr. J. Bot. 78: 159-164.
Waterman, R.J., Bidartondo, M.I., Stofberg, J*. Combs J.K., Gebauer, G. Savolainen, V., Barraclough, T.G. and Pauw, A. 2011. The effects of above and below ground mutualisms on orchid speciation and co-existence. American Naturalist 177: E54-E68.
Pauw, A. & Hawkins, J. A. 2011. Reconstruction of historical pollination rates reveals linked declines of plants and pollinators. Oikos 120: 344-349.
Pauw, A. & Bond, W.J. 2011. Mutualisms matter: pollination structures communities of oil-secreting orchids. Oikos 20 (10): 1531-1538.
M. R. Gibson, D. M. Richardson, E. Marchante, H. Marchante, J. G. Rodger, G. N. Stone, M. Byrne, A. Fuentes-Ramírez, N. George, C. Harris, S. D. Johnson, J. J. Le Roux, J. T. Miller, D. J. Murphy, A. Pauw, M. N. Prescott, E. M. Wandrag, and J. R. U. Wilson. 2011. Reproductive biology of Australian Acacia species: important mediator of invasiveness? Diversity and Distributions 17 (5): 911-933.
Geerts, S. & Pauw, A. 2011. An easy technique for assessing pollination rates in the genus Erica reveals road impact on bird pollination in the Cape Fynbos. Austral Ecology 36 (6): 656-662.
Geerts, S. & Pauw, A. 2011. Farming with native bees (Apis mellifera subsp. capensis Esch.) has mixed effects on nectar-feeding bird communities in South African Fynbos vegetation. Population Ecology 53: 333-339.
Steven D. Johnson, John C. Manning, Anton Pauw. 2009. Advances in the pollination biology of South African plants. South African Journal of Botany, Volume 75, Issue 4, Pages 625-629.
S. Geerts, A. Pauw. 2009. Hyper-specialization for long-billed bird pollination in a guild of South African plants: the Malachite Sunbird pollination syndrome. South African Journal of Botany, Volume 75, Issue 4, Pages 699-706.
P. Wester, R. Stanway, A. Pauw. 2009. Mice pollinate the Pagoda Lily, Whiteheadia bifolia (Hyacinthaceae)- First field observations with photographic documentation of rodent pollination in South Africa. South African Journal of Botany, Volume 75, Issue 4, Pages 713-719.
J.K. Combs, A. Pauw. 2009. Preliminary evidence that the long-proboscid fly, Philoliche gulosa, pollinates Disa karooica and its proposed Batesian model Pelargonium stipulaceum, South African Journal of Botany, Volume 75, Issue 4, Pages 757-761.
Geerts, S., and A. Pauw. 2009. African sunbirds hover to pollinate an invasive hummingbird-pollinated plant. Oikos 118: 573-579. doi: 10.1111/j.1600-0706.2009.17167.x
Pauw, A. Stofberg, J. and Waterman, R.J. 2009. Flies and flowers in Darwin's race. Evolution 63(1):268-279. doi:10.1111/j.1558-5646.2008.00547.x.
Oliver, E.G.H., W.R. Liltved, A. Pauw. 2008. Pterygodium vermiferum (Coryciinae), a new, autonomously self-pollinating, oil-secreting orchid from the Western Cape of South Africa. South African Journal of Botany, 74(4): 617-622.
R.J. Waterman, A. Pauw, T.G. Barraclough, V. Savolainen. 2008. Pollinators underestimated: a molecular phylogeny reveals widespread floral convergence in oil-secreting orchids (sub-tribe Coryciinae) of the Cape of South Africa. Molecular Phylogenetics and Evolution 51: 100–110. doi:10.1016/j.ympev.2008.05.020
Pauw, A. 2007. Collapse of a pollination web in small conservation areas. Ecology 88 (7):1759-1769.
Pauw, A. 2006. Floral syndromes accurately predict pollination by a specialized oil-collecting bee (Rediviva peringueyi, Melittidae) in a guild of South African orchids (Coryciinae). American Journal of Botany 93:917-926.
Pauw, A. 2005. Inversostyly: a new stylar polymorphism in an oil-secreting plant, Hemimeris racemosa (Scrophulariaceae). American Journal of Botany 92:1878-1886.
Pauw, A., Van Bael, S. A., Peters, H. A., Allison, S. D., Camargo, J. L. C., Cifuentes-Jara, M., Conserva, A., Garcia Restom, T., Heartsill-Scalley, T., Mangan, S. A., Nunez-Iturri, G., Rivera-Ocasio, E., Rountree, M., Vetter, S., & de Castilho, C. V. 2004. Physical damage in relation to carbon allocation strategies of tropical forest tree saplings. Biotropica 36 (3): 410-413.
Peters, H. A., Pauw, A., Silman, M. R., Pitman, N. C. A. & Terborgh, J. W. 2004. Falling palm fronds structure Amazonian rainforest sapling communities. Proceedings of the Royal Society of London Series B-Biological Sciences (Supplement) 271: 239-241.
Johnson, S. D., Pauw, A. & Midgley, J. 2001. Rodent pollination in the African lily Massonia depressa (Hyacinthaceae). American Journal of Botany 88(10): 1768-1773.
Pauw, A. 2000. Parental care in a polygynous group of bat-eared foxes, Otocyon megalotis (Carnivora: Canidae). African Zoology 35(1): 139-145.
Pauw, A. 1998. Pollen transfer on birds' tongues. Nature 394: 731-732.
Pauw, C. A. & Linder, H. P. 1997. Tropical African cedars ( Widdringtonia ,Cupressaceae): systematics, ecology and conservation status. Botanical Journal of the Linnean Society 123: 297-319.
Pauw, A. 2004. Variation in pollination across a fragmented landscape at the Cape of Africa. Ph.D. thesis. University of Cape Town.
Johnson, S. D. & Pauw, A. 2002. Of mice and massonias. Veld and Flora 87(4): 166-167.
Pauw, A. & Johnson, S. 2001. Table Mountain: Wilderness in a City. Readers Digest May 2001: 42-50.
Pauw, A. 2001. Aliens, Flames and Flowers: a report-back on the Cape fires. African Wildlife 55(1):20-25.
Pauw, A. 2000. The endangered Table Mountain ghost frog. Undercurrents: a newsletter of the Two Oceans Aquarium 5(2): 4-5.
Pauw, A. 2000. Fire lilies, a short note. Africa Environment and Wildlife 8(3): 14-15.
Pauw, A. 2000. Book Review, Orchids of Southern Africa . Veld and Flora 86(2): 87.
Vogelpoel, L., Cywes, S., Cywes, M. & Pauw, A. 1999. Alien Disa hybrids on Table Mountain - implications for nature conservation. Orchids South Africa 30: 26-33.
Pauw, A. 1999. Why do plants have flowers? Envirokids 20(6): 19-21.
Pauw, A. 1999. Fire power. Africa Environment and Wildlife 7(5): 80-85.
Pauw, A. 1999. The Table Mountain ghost frog. Africa Environment and Wildlife 7(1): 42-43.
Pauw, A. 1998. Pollen transfer on bird tongues. SABONET News 3 (1): 24.
Pauw, A. 1998. Will a new name save Malawi 's cedars? SABONET News 3 (1): 33-35.
Pauw, A. 1997. Bat-eared foxes. Africa Environment and Wildlife 5(3): 30-39.
Pauw, A. 1995. Cedars of the South. Cedarberg Interest Group Newsletter 1: 1-2.