Skip to main content Accessibility help
×
Home
  • Get access
    Check if you have access via personal or institutional login
  • Cited by 1
  • Print publication year: 2015
  • Online publication date: May 2015

5 - Bottom-up and top-down forces shaping wooded ecosystems: lessons from a cross-biome comparison

from Part II - Ecosystems
Asner, G. P., Levick, S. R., Kennedy-Bowdoin, T., et al. (2009). Large-scale impacts of herbivores on the structural diversity of African savannas. Proceedings of the National Academy of Sciences of the USA, 106, 4947–4952.
Baldeck, C. A, Colgan, M. S., Féret, J.-B., et al. (2014). Landscape-scale variation in plant community composition of an African savanna from airborne species mapping. Ecological Applications, 24, 84–93.
Beard, K. H., Vogt, K. A. and Kulmatiski, A. (2002). Top-down effects of a terrestrial frog on forest nutrient dynamics. Oecologia, 133, 583–593.
Bengtsson, J., Nilsson, S. G., Franc, A. and Menozzi, P. (2000). Biodiversity, disturbances, ecosystem function and management of European forests. Forest Ecology and Management, 132, 39–50.
Birks, H. J. B. (2005). Mind the gap: how open were European primeval forests? Trends in Ecology and Evolution, 20,154–156.
Bobiec, A. (2007). The influence of gaps on tree regeneration: a case study of the mixed lime-hornbeam (Tilio-Carpinetum Tracz. 1962) communities in the Białowieża Primeval Forest. Polish Journal of Ecology, 55, 441–455.
Bobiec, A., van der Burgt, H., Meijer, K., et al. (2000). Rich deciduous forests in Białowieża as a dynamic mosaic of developmental phases: premises for nature conservation and restoration management. Forest Ecology and Management, 130, 159–175.
Bonan, G. A. B. and Shugart, H. H. (1989). Environmental factors and ecological processes in boreal forests. Annual Review of Ecology and Systematics, 20, 1–28.
Bond, W. J. (2005). Large parts of the world are brown or black: a different view on the ‘Green World’ hypothesis. Journal of Vegetation Science, 16, 261–266.
Bond, W. J. (2008). What limits trees in C-4 grasslands and savannas?Annual Review of Ecology, Evolution, and Systematics, 39, 641–659.
Bond, W. J. and Keeley, J. E. (2005). Fire as a global ‘herbivore’: the ecology and evolution of flammable ecosystems. Trends in Ecology and Evolution, 20, 387–394.
Bond, W. J. and Loffell, D. (2001). Introduction of giraffe changes acacia distribution in a South African savanna. African Journal of Ecology, 39, 286–294.
Bond, W. J. and Midgley, G. F. (2000). A proposed CO2-controlled mechanism of woody plant invasion in grasslands and savannas. Global Change Biology, 6, 865–869.
Bond, W. J. and van Wilgen, B. W. (1996). Fire and Plants. London: Chapman and Hall.
Brandner, T. A., Peterson, R. O. and Risenhoover, K. L. (1990). Balsam fir on Isle Royale: effects of moose herbivory and population density. Ecology, 71, 155–164.
Bryant, J. P. and Chapin, F. S. III. (1986). Browsing-woody plant interactions during boreal forest plant succession. In Forest Ecosystems in the Alaskan Taiga: A Synthesis of Structure and Function – Ecological Studies, Volume 57, ed. K. Van Cleve, F. S.Chapin, P. W.Flanagan, L. A. Viereck and Dyrness, C. T.. Berlin: Springer-Verlag, pp. 213–225.
Bryant, J. P., Provenza, F. D., Pastor, J., et al. (1991). Interactions between woody plants and browsing mammals mediated by secondary metabolites. Annual Review of Ecology and Systematics, 22, 431–446.
Bryant, J. P., Reichardt, P. B. and Clausen, T. P. (1992). Chemically mediated interactions between woody plants and browsing mammals. Journal of Range Management, 45, 18–24.
Buitenwerf, R., Bond, W. J., Stevens, N. and Trollope, W. S. W. (2012). Increased tree densities in South African savannas: > 50 years of data suggests CO2 as a driver. Global Change Biology, 18, 675–684.
Busing, R. T. and Brokaw, N. (2002). Tree species diversity in temperate and tropical forest gaps: the role of lottery recruitment. Folia Geobotanica, 37, 33–43.
Carson, W. P., Anderson, J. T., Leigh, E. G. Jr. and Schnitzer, S. A. (2008). Challenges associated with testing and falsyfying the Janzen-Connell hypothesis: a review and critique. In Tropical Forest Ecology, ed. Carson, W. P. and Schnitzer, S. A.. Oxford: Wiley-Blackwell, pp. 210–241.
Coley, P. D., Bryant, J. P. and Chapin, F. S. III. (1985). Resource availability and plant antiherbivore defense. Science, 230, 895–899.
Connell, J. H. (1971). On the role of natural enemies in preventing competitive exclusion in some marine animals and in rain forest trees. In Dynamics of populations, ed. den Boer, P. J. and Gradwell, G. R.. Wageningen: Centre for Agricultural Publications and Documentation, pp. 298–310.
Côté, S. D., Rooney, T. P., Trembley, J.-P., Dussault, C. and Waller, D. M. (2004). Ecological impacts of deer overabundance. Annual Review of Ecology, Evolution, and Systematics, 35, 113–147.
Creel, S., Winnie Jr., J. A., Christianson, D. and Liley, S. (2008). Time and space in general models of antipredator response: test with wolves and elk. Animal Behaviour, 76, 1139–1146.
Cromsigt, J. P. G. M. and Kuijper, D. P. J. (2011). Revisiting the browsing lawn concept: evolutionary interactions or pruning herbivores? Perspectives in Plant Ecology, Evolution and Systematics, 13, 207–215.
Cromsigt, J. P. G. M. and Olff, H. (2008) Dynamics of grazing lawn formation: an experimental test of the role of scale-dependent processes. Oikos, 117, 1444–1452.
Cromsigt, J. P. G. M. and Te Beest, M. (2014). Restoration of a megaherbivore – landscape-level impacts of white rhinoceros in Kruger National Park.Journal of Ecology. DOI: 10.1111/1365–2745.12218.
Cromsigt, J. P. G. M., Kuijper, D. P. J., Adam, M., et al. (2013). Hunting for fear: innovating management of human–wildlife conflicts. Journal of Applied Ecology, 50, 544–549.
Danell, K., Bergström, R., Edenius, L. and Ericsson, G. (2003). Ungulates as drivers of tree population dynamics at module and genet levels. Forest Ecology and Management, 181, 67–76.
DeAngelis, D. L. (1992). Dynamics of Nutrient Cycling and Food Webs. London: Chapman and Hall.
Dirzo, R. and Miranda, A. (1991). Altered patterns of herbivory and diversity in the forest understory: a case study of the possible consequences of contemporary defaunation. In Plant–Animal Interactions: Evolutionary Ecology in Tropical and Temperate Regions, ed. Price, P. W., Lewinsohn, P. W., Fernandes, G. W. and Benson, W. W.. New York: Wiley, pp. 273–287.
Du Toit, J. T. and Olff, H. (2014). Generalities in grazing and browsing ecology: using across-guild comparisons to control contingencies.Oecologia. DOI: 10.1007/s00442–013–2864–8.
Dunham, A. E. (2008). Above and below ground impacts of terrestrial mammals and birds in a tropical forest. Oikos, 117, 571–579.
Dyer, L. A. and Letourneau, D. K. (1999). Relative strengths of top-down and bottom-up forces in a tropical forest community. Oecologia, 119, 265–274.
Dyer, L. A., Letourneau, D. K., Chavarria, G. V. and Amorett, D. S. (2010). Herbivores on a dominant understory shrub increase local plant diversity in rain forest communities. Ecology, 91, 3707–3718.
Ellis, E. C. (2011). Anthropogenic transformation of the terrestrial biosphere. Philosophical Transactions of the Royal Society A, 369, 1010–1035.
Ellis, E. C. and Ramankutty, N. (2008). Putting people in the map: anthropogenic biomes of the world. Frontiers in Ecology and Environments, 6, 439–447.
Fortin, D., Beyer, H. L., Boyce, M. S., et al. (2005). Wolves influence elk movements: Behavior shapes a trophic cascade in Yellowstone National Park. Ecology, 86, 1320–1330.
Fretwell, S. D. (1977). The regulation of plant communities by the food chains exploiting them. Perspectives in Biology and Medicine, 20, 169–185.
Green, P. T., O'Dowd, D. J. and Lake, P. S. (2008). Recruitment dynamics in a rainforest seedling community: context-independent impact of a keystone consumer. Oecologia, 156, 373–385.
Gripenberg, S. and Roslin, T. (2007). Up or down in space? Uniting the bottom-up versus top-down paradigm and spatial ecology. Oikos, 116, 181–188.
Guldemond, R. and Van Aarde, R. (2008). A meta-analysis of the impact of African elephants on savanna vegetation. Journal of Wildlife Management, 72, 892–899.
Hall, S. J. G. (2008). A comparative analysis of the habitat of the extinct aurochs and other prehistoric mammals in Britain. Ecography, 31, 187–190.
Halofsky, J. S. and Ripple, W. J. (2008). Fine-scale predation risk on elk after wolf reintroduction in Yellowstone National Park, USA. Oecologia, 155, 869–877.
Hannah, L., Carr, J. L. and Landerani, A. (1995). Human disturbance and natural habitat – a biome level analysis of a global data set. Biodiversity and Conservation, 4, 128–155.
Higgins, S. I., Bond, W. J., February, E. C., et al. (2007). Effects of four decades of fire manipulation on woody vegetation structure in savanna. Ecology, 88, 1119–1125.
Hirota, M., Holmgren, M., Van Nes, E. H. and Scheffer, M. (2011). Global resilience of tropical forest and savanna to critical transitions. Science, 334, 232–235.
Hirsch, B. T., Kays, R., Pereira, V. E. and Jansen, P. A. (2012). Directed seed dispersal toward areas with low conspecific tree density by a scatter-hoarding rodent. Ecology Letters, 15, 1423–1429.
Holdo, R. M., Sinclair, A. R. E., Dobson, A. P., et al. (2009). A disease-mediated trophic cascade in the Serengeti and its implications for ecosystem C. PLoS Biology, 7, e1000210.
Hopcraft, J. G. C., Olff, H. and Sinclair, A. R. E. (2010). Herbivores, resources and risks: alternating regulation along primary environmental gradients in savannas. Trends in Ecology and Evolution, 25 (2), 119–128.
Hubbell, S. P. (2005). Neutral theory in community ecology and the hypothesis of functional equivalence. Functional Ecology, 19, 166–172.
Hubbell, S. P. (2006). Neutral theory and the evolution of ecological equivalence. Ecology, 87, 1387–1398.
Hyatt, L. A., Rosenberg, M. S., Howard, T. G., et al. (2003). The distance dependence predictions of the Janzen-Conell hypothesis: a meta-analyis. Oikos, 103, 590–602.
Jansen, P. A., Hirsch, B. T., Emsens, W. J., et al. (2012). Thieving rodents as substitute dispersers of megafaunal seeds. Proceedings of the National Academy of Sciences of the USA, 109, 12610–12615.
Janzen, D. H. (1970). Herbivores and number of tree species in tropical forests. American Naturalist, 104, 501–528.
Jędrzejewska, B. and Jędrzejewski, W. (2005). Large carnivores and ungulates in European temperate forest ecosystems: bottom-up and top-down control. In Large Carnivores and the Conservation of Biodiversity, ed. Ray, J. C., Redford, K. H., Steneck, R. S. and Berger, J.. Washington: Island Press, pp. 230–245.
Jędrzejewska, B., Jędrzejewski, W., Bunevich, A., , N., Miłkowski, L. and Krasiński, Z. A. (1997). Factors shaping population densities and increased rates of ungulates in Białowieża Primeval Forest (Poland and Belarus) in the 19th and 20th century. Acta Theriologica, 42, 399–451.
Jędrzejewski, W., Schmidt, K., Theuerkauf, J., et al. (2002). Kill rates and predation by wolves on ungulate populations in Białowieża primeval forest (Poland). Ecology, 83, 1341–1356.
Kalka, M. B., Smith, A. R. and Kalko, E. K. V. (2008). Bats limit arthropods and herbivory in a tropical forest. Science, 320, 71–71.
Kerley, G. I. H., Landman, M., Kruger, L., et al. (2008). Effects of elephants on ecosystems and biodiversity. In Assessment of South African Elephant Management, ed. Scholes, R. J. and Mennell, K. G.. Johannesburg: Witwatersrand University Press, pp. 146–205.
Kerley, G. I. H., Kowalczyk, R. and Cromsigt, J. P. G. M. (2012). Conservation implications of the refugee species concept and the European bison: king of the forest or refugee in a marginal habitat? Ecography, 35, 519–529.
Kielland, K. and Bryant, J. P. (1998). Moose herbivory in taiga: effects on biogeochemistry and vegetation dynamics in primary succession. Oikos, 82, 377–383.
Kuijper, D. P. J. (2011). Lack of natural control mechanisms increases wildlife-forestry conflict in managed temperate European forest systems. European Journal of Forest Research, 130, 895–909
Kuijper, D. P. J., Cromsigt, J. P. M. G., Churski, M., et al. (2009). Do ungulates preferentially feed in forest gaps in European temperate forests? Forest Ecology and Management, 258, 1528–1535.
Kuijper, D. P. J., Cromsigt, J. P. G. M., Jędrzejewska, B., et al. (2010a). Bottom-up versus top-down control of tree regeneration in the Białowieża Primeval Forest, Poland. Journal of Ecology, 98, 888–899.
Kuijper, D. P. J., Jędrzejewska, B., Brzeziecki, B., et al. (2010b). Fluctuating ungulate density shapes tree recruitment in natural stands of the Białowieża Primeval forest, Poland. Journal of Vegetation Science, 21, 1082–1098.
Kuijper, D. P. J., de Kleine, C., Churski, M., et al. (2013). Landscape of fear in Europe: wolves affect spatial patterns of ungulate browsing in Białowieża Primeval Forest, Poland. Ecography 36, 1263–1275. DOI: 10.1111/j.1600–0587.2013.00266.x.
Kuijper, D. P. J., Verwijmeren, M., Churski, M., et al. (2014). What cues do ungulates use to assess predation risk in dense temperate forests?PLoS One 9(1): e84607. DOI: 10.1371/journal.pone.0084607.
Kuuluvainen, T. (1992). Tree architecture adapted to efficient light utilization: is there a basis for latitudinal gradients?Oikos, 65, 275–284.
Laliberte, A. S. and Ripple, W. J. (2004). Range contractions of North American carnivores and ungulates. BioScience, 54, 123–138.
Lieth, H. and Whittaker, R. H. (eds.) (1975). Primary Productivity of the Biosphere: Ecological Studies Vol. 14. New York: Springer Verlag.
Makarieva, A. M. and Gorshkov, V. G. (2010). The biotic pump: condensation, atmospheric dynamics and climate. International Journal of Water, 5, 365–385.
Malmström, C. M. and Raffa, K. F. (2000). Biotic disturbance agents in the boreal forest: considerations for vegetation change models. Global Change Biology, 6, 35–48.
Mao, J. S., Boyce, M. S., Smith, D. W., et al. (2005). Habitat selection by elk before and after wolf reintroduction in Yellowstone National Park. Journal of Wildlife Management, 69, 1691–1707.
McCullough, D. G., Werner, R. A. and Neumann, D. (1998). Fire and insects in northern and boreal forest ecosystems of North America. Annual Review of Entomology, 43, 107–127.
McInnes, P., Naiman, R. J., Pastor, J. and Cohen, Y. (1992). Effects of moose browsing on vegetation and litter of the boreal forest, Isle Royale, Michigan, USA. Ecology, 73, 2059–2075.
McLaren, B. E. and Peterson, R. O. (1994). Wolves, moose, and tree rings on Isle Royale. Science, 266, 1555–1558.
Michalczuk, C. (2001). Forest habitats and tree stands of the Białowieża National Park. In Phytocoenosis 13, Supplementum Cartographiae Geobotanicae 13, Warszawa – Białowieża: Białowieża Geobotanical Station of Warsaw University.
Mitchell, F. J. G. (2005). How open were European primeval forests? Hypothesis testing using palaeoecological data. Journal of Ecology, 93, 168–177.
Modry, M., Hubeny, D. and Rejsek, K. (2004). Differential response of naturally regenerated European shade tolerant tree species to soil type and light availability. Forest Ecology and Management, 188, 185–195.
Nams, V. O., Folkard, N. F. G. and Smith, J. N. M. (1993). Effects of nitrogen fertilization on several woody and non woody boreal forest species. Canadian Journal of Botany, 71, 93–97.
Nores, C., Llaneza, L. and Alvarez, M. A. (2008). Wild boar Sus scrofa mortality by hunting and wolf Canis lupus predation: an example in northern Spain. Wildlife Biology, 14, 44–51.
Oksanen, L. and Oksanen, T. (2000). The logic and realism of the hypothesis of exploitation ecosystems. The American Naturalist, 155, 703–723.
Oksanen, L., Fretwell, S. D., Arruda, J. and Niemelä, P. (1981). Exploitation ecosystems in gradients of primary productivity. The American Naturalist, 118, 240–261.
Olff, H., Vera, F. W. M., Bokdam, J., et al. (1999). Shifting mosaics in grazed woodlands driven by the alternation of plant facilitation and competition. Plant Biology, 1, 127–137.
Owen-Smith, R. N. (1988). Megaherbivores: the Influence of Very Large Body Size on Ecology. Cambridge, UK: Cambridge University Press.
Pastor, J. and Naiman, R. J. (1992). Selective foraging and ecosystem processes in boreal forests. American Naturalist, 139, 690–705.
Pastor, J., Naiman, R. J., Dewey, B. and McInnes, P. (1988). Moose, microbes and the boreal forest. BioScience, 38, 770–777.
Pastor, J., Dewey, B., Naiman, R. J., McInnes, P. and Cohen, Y. (1993). Moose browsing and soil fertility in the boreal forests of Isle Royale National Park. Ecology, 74, 467–480.
Peterson, R. O., Page, R. E. and Dodge, K. M. (1984).Wolves, moose, and the allometry of population cycles. Science, 224, 1350–1352.
Polis, G. A. and Strong, D. R. (1996). Food web complexity and community dynamics. The American Naturalist, 147, 813–846.
Prentice, I. C., Cramer, W., Harrison, W. P., et al. (1992). A global biome model based on plant physiology and dominance, soil properties and climate. Journal of Biogeography, 19, 117–134.
Pringle, R. M., Young, T. P., Rubenstein, D. I. and McCauley, D. J. (2007). Herbivore-initiated interaction cascades and their modulation by productivity in an African savanna. Proceedings of the National Academy of Sciences of the USA, 104, 193–197.
Prins, H. T. and Van der Jeugd, H. P. (1993). Herbivore population crashes and woodland structure in East Africa. Journal of Ecology, 81, 305–314.
Roques, K. G., O'Connor, T. G. and Watkinson, A. R. (2001). Dynamics of shrub encroachment in an African savanna: relative influences of fire, herbivory, rainfall and density dependence. Journal of Applied Ecology, 38, 268–280.
Runkle, J. R. (1981). Gap regeneration in some old-growth forests of the eastern United States. Ecology, 62, 1041–1051.
Samojlik, T. and Kuijper, D. P. J. (2013). Grazed wood pasture versus browsed high forests: impact of ungulates on forest landscapes from the perspective of the Białowieża Primeval Forest. In Trees, Forested Landscapes and Grazing Animals: A European Perspective on Woodlands and Grazed Treescapes, ed. Rotherham, I. D.. London/New York: Routledge, pp. 143–162.
Samojlik, T., Jędrzejewska, B., Krasnodębski, D., Dulinicz, M. and Olczak, H. (2007). Man in the ancient forest. Academia, The Magazine of the Polish Academy of Sciences, 4(12), 36–37.
Sankaran, M., Hanan, N. P, Scholes, R. J., et al. (2005). Determinants of woody cover in African savannas. Nature, 438, 846–849.
Sankaran, M, Augustine, D. J. and Ratnam, J. (2013). Native ungulates of diverse body sizes collectively regulate long-term woody plant demography and structure of a semi-arid savanna. Journal of Ecology, 101, 1389–1399.
Scheffer, M., Hirotaa, M., Holmgren, M., Van Nes, E. H. and Chapin III, F. S. (2012). Thresholds for boreal biome transitions. Proceedings of the National Academy of Sciences of the USA, 109, 21384–21389.
Scholes, R. J. (1999). Savannas. In The Vegetation of Southern Africa, eds. Cowling, R., Richardson, D. and Pierce, S.. Cambridge, UK: Cambridge University Press, pp. 258–277.
Scholes, R. J. and Archer, S. R. (1997). Tree-grass interactions in sanannas. Annual Review of Ecology, Evolution, and Systematics, 28, 517–544.
Sheil, D. and Murdiyarso, D. (2009). How forests attract rain: an examination of a new hypothesis. BioScience, 59, 341–347.
Silman, M. R., Terborgh, J. W. and Kiltie, R. A. (2003). Population regulation of a dominant rain forest tree by a major seed predator. Ecology, 84, 431–438.
Sinclair, A. R. E., Metzger, K., Brashares, J. S., et al. (2010). Trophic cascades in African savanna: Serengeti as a case study. In Trophic Cascades: Predators, Prey, and the Changing Dynamics of Nature, ed. Estes, J. A. and Terborgh, J.. Washington: Island Press, pp. 255–274.
Skowno, A. L., Midgley, J. J., Bond, W. J. and Balfour, D. (1999). Secondary succession in Acacia nilotica (L.) savanna in the Hluhluwe Game Reserve, South Africa. Plant Ecology, 145, 1–9.
Soulé, M. E., Estes, J. A., Berger, J. and Martinez del Rio, C. (2003). Ecological effectiveness: conservation goals for interactive species. Conservation Biology, 17, 1238–1250.
Staver, C. A., Bond, W. J., Stock, W. D., van Rensburg, S. J. and Waldram, M. S. (2009). Browsing and fire interact to suppress tree density in an African savanna. Ecological Applications, 19, 1909–1919.
Staver, C. A., Archibald, S. and Levin, S. A. (2011). The global extent and determinants of savanna and forest as alternative biome states. Science, 334, 230–232.
Svenning, J.-C. (2002). A review of natural vegetation openness in north-western Europe. Biological Conservation, 104, 133–148.
Szwagrzyk, J., Szewczyk, J. and Maciejewski, Z. (2012). Shade-tolerant tree species from temperate forests differ in their competitive abilities: a case study from Roztocze, south-eastern Poland. Forest Ecology and Management, 282, 28–35.
Terborgh, J. (1985). The vertical component of plant species diversity in temperate and tropical forests. The American Naturalist, 126, 760–776.
Terborgh, J. (1988). The big things that run the world – a sequel to E. O. Wilson. Conservation Biology, 2, 402–403.
Terborgh, J., Foster, R. B. and Nunez, P. (1996). Tropical tree communities: a test of the nonequilibrium hypothesis. Ecology, 77, 561–567.
Terborgh, J., Lopez, L., Nuñez, V. P., et al. (2001). Ecological meltdown in predator-free forest fragments. Science, 294, 1923–1926.
Terborgh, J., Feeley, K., Silman, M., Nuñez, P. and Balukjian, B. (2006). Vegetation dynamics of predator-free land-bridge islands. Journal of Ecology, 94, 253–263.
Thaker, M., Vanak, A. T., Owen, C. R., et al. (2011). Minimizing predation risk in a landscape of multiple predators: effects on the spatial distribution of African ungulates. Ecology, 92, 398–407.
Turkington, R., John, E., Watson, S. and Seccombe-Hett, P. (2002). The effects of fertilization and herbivory on the herbaceous vegetation of the boreal forest in north-western Canada: a 10-year study. Journal of Ecology, 90, 325–337.
Underwood, R. (1982). Vigilance behaviour in grazing African antelopes. Behaviour, 79, 82–107.
Valeix, M., Loveridge, A. J., Chamaillé-Jammes, S., et al. (2009). Behavioral adjustments of African herbivores to predation risk by lions: spatiotemporal variations influence habitat use. Ecology, 90, 23–30.
Van Bael, S. A. and Brawn, J. D. (2005). The direct and indirect effects of insectivory by birds in two contrasting Neotropical forests. Oecologia, 143, 106–116.
Van Cleve, K., Oliver, L., Schlentner, R., Viereck, L. A. and Dyrness, C. T. (1983). Productivity and nutrient cycling in taiga forest ecosystems. Canadian Journal of Forest Research, 13, 747–766.
Van Cleve, K., Chapin, F. S. III, Dyrness, C. T. and Viereck, L. A. (1991). Elemental cycling in taiga forests: state-factor control. BioScience, 41(2), 78–88.
Van den Berghe, C., Frelechoux, F., Gadallah, F. and Butler, A. (2006). Competitive effects of herbaceous vegetation on tree seedling emergence, growth and survival: does gap size matter? Journal of Vegetation Science, 17, 481–488.
Van der Waal, C., Kool, A., Meijer, S. S., et al. (2011). Large herbivores may alter vegetation structure of semi-arid savannas through soil nutrient mediation. Oecologia, 165, 1095–1107.
Wakeling, J. L., Staver, A. C. and Bond, W. J. (2011). Simply the best: the transition of savanna saplings to trees. Oikos, 120, 1448–1451.
Waldram, M., Bond, W. and Stock, W. (2008). Ecological engineering by a mega-grazer: white rhino impacts on a South African savanna. Ecosystems, 11, 101–112.
Whittaker, R. H. (1962). Classification of natural communities. Botanical Review, 28, 1–239.
Whittaker, R. H. (1975). Communities and Ecosystems, 2nd edn. London: Collier MacMillan.
Wigley, B. J.Bond, W. J. and Hoffman, M. T. (2010). Thicket expansion in a South African savanna under divergent land use: local vs. global drivers?Global Change Biology, 16, 964–976.
Wilson, E. O. (1987). The little things that run the world (The importance and conservation of invertebrates). Conservation Biology, 1, 344–346.
Wright, S. J., Gompper, M. E. and Deleon, B. (1994). Are large predators keystone species in Neotropical forests – the evidence from Barro Colorado Island. Oikos, 71, 279–294.
Woodroffe, R. (2000). Predators and people: using human densities to interpret declines of large carnivores. Animal Conservation, 3, 165–173.
Young, H. S., McCauley, D. J., Helgen, K. M., et al. (2013). Effects of mammalian herbivore declines on plant communities: observations and experiments in an African savanna. Journal of Ecology, 101, 1030–1041.