Species Competition and Predation
Biogeochemistry represents the interaction of biology, chemistry, and geology in the Earth system. For many processes, an understanding of biological uptake and emission, chemical processing, and geological sequestration is necessary to resolve the sources and sinks of a particular constituent. For example, to discover the sources and sinks of atmospheric carbon dioxide, it is important to understand how biota take up carbon dioxide and chemically convert the carbon to organic carbon, and then how this organic carbon is used either to produce energy by biota or is deposited to the land or ocean surface and can become sequestered in geological formations.
KeywordsNatural Enemy Density Dependence Interspecific Competition Intraspecific Competition Species Coexistence
- Apparent competition
The tendency for an increase in the density of a species to increase the impact of a natural enemy on that same species or other species.
The tendency for an increase in the density of a species to have a negative effect on the survival or reproduction of individuals of the same species or of other species by reducing resource abundance, reducing access to resources, or by direct harm of one individual organism on another associated with resource acquisition.
- Density dependence
The tendency for an increase in the density of a species to have a negative effect on the survival or reproduction of individuals of the same or different species. As used in this essay, the species in question are in the same guild. Competition and apparent competition are special cases of density dependence.
- Feedback loop
A chain of species interactions from one member of a guild, through other species, back to a species in that same guild. Feedback loops transmit density dependence.
A group of species potentially co-occurring in the same locality and having similar ecology in the sense of depending on the same or similar resources, often seeking those resources in similar ways, and susceptible to the same or similar natural enemies. The standard of similarity in this definition is not precise, and varies depending on the purpose of the investigator.
- Natural enemy
An organism that benefits its own reproduction or survival by harming the individuals of a given species, commonly by feeding on them.
- Niche overlap
For any pair of species, the degree to which density dependence through feedback loops is concentrated between species compared to within species. It is measured by the quantity ρ which varies between zero for no overlap (no interspecific density dependence) and 1 for complete overlap (interspecific density dependence is on average equal to intraspecific density dependence).
A species that gains food by killing and consuming individuals of the species in the ecological guild in question.
- Species average fitness
For a given species in a guild, it is a numerical measure of how well that species is adapted to the environment with the property that it predicts which species would dominate if the niche overlaps, ρ, were all equal to 1. It is normally related to the long-term average per capita growth rates of the species measured at fixed levels of competition and apparent competition. In this essay, the fitnesses κ are obtained from per capita growth rates at zero levels of competition and apparent competition, which are achieved by setting all members of a guild at zero density. These growth rates are then divided by scaling factors that correct for differences between species in their levels of sensitivity to competition and apparent competition.
- Stable coexistence
The tendency of the members of a guild to recover when individually perturbed to low density, allowing their long-term persistence in the presence of interactions with other guild members.
I am grateful for comments on the manuscript by Jonathan Levine and for support from the National Science Foundation grant numbers DEB-0717222 and DEB-0816231.
- 1.Murdoch WW, Briggs CJ, Nisbet RM (2003) Consumer-resource dynamics. Princeton University Press, Princeton, NJGoogle Scholar
- 3.MacArthur RH (1972) Geographical ecology: patterns in the distribution of species. Harper & Row, New YorkGoogle Scholar
- 4.Tilman D (1982) Resource competition and community structure. Princeton University Press, Princeton, NJGoogle Scholar
- 6.Harper JL (1977) Population biology of plants. Academic, LondonGoogle Scholar
- 13.Chesson P (2008) Quantifying and testing species coexistence mechanisms. In: Valladares F, Camacho A, Elosegui A, Gracia C, Estrada M, Senar JC, Gili JM (eds) Unity in diversity: reflections on ecology after the legacy of Ramon Margalef. Fundacion BBVA, Bilbao, pp 119–164Google Scholar
- 19.Nicholson AJ (1937) The role of competition in determining animal populations. JSIR (Australia) 10:101–106Google Scholar
- 21.Roughgarden J (1989) Community structure and assembly. In: Roughgarden J, May RM, Levin SA (eds) Perspectives in ecological theory. Princeton University Press, Princeton, NJ, pp 203–226Google Scholar
- 29.Chase JM, Leibold MA (2003) Ecological Niches: linking classical and contemporary approaches. The University of Chicago Press, ChicagoGoogle Scholar
- 31.Tilman D (1988) Plant strategies and the dynamics and structure of plant communities. Princeton University Press, Princeton, NJGoogle Scholar
- 32.Hubbell SP (2001) The unified neutral theory of biodiversity and biogeography. Princeton University Press, Princeton, NJGoogle Scholar
- 33.Purves DW, Pacala SW (2005) Ecological drift in niche-structured communities: neutral pattern does not imply neutral process. In: Burslem D, Pinard M, Hartley S (eds) Biotic interactions in the tropics. Cambridge University Press, Cambridge, UK, pp 103–138Google Scholar
- 44.Knowlton JL, Donlan CJ, Roemer GW, Samaniego-Herrera A, Kertt BS, Wood B, Aguirre-Munoz A, Faulknier KR, Tershy BR (2007) Eradication of non-native mammals and the status of insular mammals on the California Channel Islands, USA, and Pacific Baja California Peninsula Islands, Mexico. Southwest Nat 52:528–540CrossRefGoogle Scholar
- 45.Stephens DW, Brown JS, Ydenberg RC (eds) (2007) Foraging: behavior and ecology. University of Chicago Press, ChicagoGoogle Scholar
- 52.Murdoch WW, Bence J (1987) General predators and unstable prey populations. In: Kerfoot WC, Sih A (eds) Predation: direct and indirect impacts on aquatic communities. University Press of New England, Hanover and London, pp 17–30Google Scholar
- 55.Stephens DW, Krebs JR (1986) Foraging theory. The Princeton University Press, Princeton, NJGoogle Scholar
- 57.Krivan V (2003) Competitive co-existence by adaptive predators. Evol Ecol Res 5:1163–1182Google Scholar
- 58.May RM (1974) Stability and complexity in model ecosystems, 2nd edn. Princeton University Press, Princeton, NJGoogle Scholar
- 79.Connell JH (1979) Tropical rainforests and coral reefs as open non-equilibrium systems. In: Anderson RM, Turner BD, Taylor LR (eds) Population dynamics. Blackwell Scientific Publications, Oxford, pp 141–163Google Scholar
- 86.Connell JH (1970) On the role of natural enemies in preventing competitive exclusion in some marine animals and rainforest trees. In: den Boer PJ, Gradwell G (eds) Dynamics of populations. Centre for Agricultural Publishing and Documentation, Wageningen, pp 298–312Google Scholar
- 93.Drury WH (1998) Chance and change: ecology for conservationists. University of California Press, Berkeley, CalifGoogle Scholar
- 95.Kinzig A, Pacala S, Tilman D (eds) (2001) The functional consequences of biodiversity. Princeton University Press, Princeton, NJGoogle Scholar
- 100.Simberloff D (1995) Why do introduced species appear to devastate islands more than mainland areas? Pac Sci 49:87–97Google Scholar
- 101.Huston MA (1994) Biological diversity, 1st edn. Cambridge University Press, CambridgeGoogle Scholar
- 103.Elton C (1958) The ecology of invasions by animals and plants. Methuen and Co, LondonGoogle Scholar
- 114.Terborgh J, Estes JA (2010) Trophic cascades: predators, prey, and the changing dynamics of nature. Island Press, Washington DCGoogle Scholar
- 122.Davis MB (1986) Climatic instability, time-lags and community disequilibrium. In: Diamond J, Case T (eds) Community ecology. Harper and Row, Cambridge, pp 269–284Google Scholar