Species Richness: Small Scale

Abstract

Species richness, defined as the number of species per unit area, is the simplest measure of biodiversity. Small‐scale species richness generally refers to species richness at the scale of a single community, habitat or microhabitat. Understanding the factors that affect and are affected by small‐scale species richness is fundamental to understanding how ecological communities are assembled and function and how biodiversity is maintained. Several factors affect small‐scale species richness, including geographic factors such as the regional species pool, dispersal distance and ease of dispersal, biological factors such as competition, facilitation, and predation as well as environmental factors such as resource availability, environmental heterogeneity and disturbance frequency and intensity. The importance of these factors varies with scale of observation. Further, small‐scale richness can impact aspects of ecosystem function including productivity, stability, and invasibility.

Key Concepts

  • Small‐scale species richness is the number of species per unit area at the scale of a single community, habitat or microhabitat.
  • Species richness is similar to alpha (α) diversity, or the number of species occurring at the local scale in a relatively homogeneous area.
  • Many factors affect small‐scale species richness, including geographic (e.g. species pool, dispersal), biotic (e.g. competition, predation, facilitation) and abiotic (e.g. resource availability, environmental heterogeneity, disturbance frequency and intensity).
  • The species pool is the set of species adapted to a site that are regionally available to colonise that site, and, in conjunction with dispersal processes, define the universe from which the ecological community is assembled.
  • Immigration is affected by the distance between suitable habitat sites and the ability of propagules to become established at the local site, and can significantly increase species richness.
  • Competition tends to decrease small‐scale richness, and its impact is shaped by resource availability, the specific resources being competed for and ecological disturbances that reduce competition.
  • Interactions among predators and prey, or pathogens and parasites and their hosts, can maintain or alter small‐scale diversity, the impact being largely dependent on the level of dominance of the species directly impacted.
  • While there is some evidence of a positive relationship between small‐scale richness and productivity, other factors such as the number and identity of functional groups may be the direct cause of the relationship.
  • Small‐scale richness has complex effects on the stability and invasibility of local sites.

Keywords: biodiversity; community ecology; competition; diversity; scale; ecosystem function; species richness

Figure 1. Log‐log species–area curve of vascular plant richness from fine scales to global land area, starting from within the Carolinas, USA. The lowest six values are mean richness values from 1472 vegetation plots of 0.1 ha of the Carolina Vegetation Survey (CVS), with solid line as the mean species accumulation rate for these scales. Global richness is an estimate of 250 000 species. Reproduced with permission from Fridley et al. (2005). ©Ecological Society of America.
Figure 2. Species–area curves for four habitats, Las Cruces, Costa Rica, showing different rates of species accumulation along a transect in old‐growth forest, a forest gap, an open field and under a shade tree in the open field (data from Rebecca Brown). Area in this example refers to distance along the transect.
Figure 3. Species richness peaks at low to intermediate levels along a gradient of fertility or primary productivity in grasslands and open savannas, after which competition for light becomes important and the shorter species are lost, reducing richness. Grasslands with very high richness are chronically disturbed by some factor such as fire or grazing or mowing that reduces plant height and thus reduces competition for light, allowing richness to increase along a fertility gradient longer before the asymmetric competition for light becomes a factor. Reprinted from Peet et al. (2014) © Oxford University Press.
Figure 4. With increasing canopy cover from open grasslands through open woodlands to closed canopy temperate forests, light available to the herbaceous layer steadily declines. As the available light declines, it takes greater fertility for the herbaceous layer to become sufficiently robust for asymmetric light competition to become important, with the consequence that the peak in richness shifts progressively toward more fertile sites. Reprinted from Peet et al. (2014) © Oxford University Press.
close

References

Adler PB, Seabloom EW, Borer ET, et al. (2011) Productivity is a poor predictor of plant species richness. Science 333: 1750–1753.

Bohn K, Pavlick R, Reu B and Kleidon A (2014) The strengths of r‐ and K‐selection shape diversity‐disturbance relationships. Plos One 9: e95659.

Brown RL and Peet RK (2003) Diversity and invasibility of southern Appalachian plant communities. Ecology 84: 32–39.

Bruno JF (2000) Facilitation of cobble beach plant communities through habitat modification by Spartina alterniflora. Ecology 81: 1179–1192.

Bruno JF, Stachowicz JJ and Bertness MD (2003) Inclusion of facilitation into ecological theory. Trends in Ecology & Evolution 18: 119–125.

Cadotte MW, Arnillas CA, Livingstone SW and Yasui S‐LE (2015) Predicting communities from functional traits. Trends in Ecology & Evolution 30: 510–511.

Condit R, Hubbell SP and LaFrankie JV (1996) Species–area and species–individual relationships for tropical trees: a comparison of three 50‐ha plots. Journal of Ecology 84: 549–562.

Connell JH (1971) On the role of natural enemies in preventing competitive exclusion in some marine animals and rain forest trees. In: den Boer PJ and Gradwell GR (eds) Dynamics of Populations: Proceedings of the Advanced Study Institute on Dynamics of Numbers in Populations, Oosterbeek, 1970, pp. 298–312. Wageningen, Netherlands: Center for Agricultural Publishing and Documentation.

Connell JH (1978) Diversity in tropical rainforests and coral reefs. Science 199: 1302–1310.

Davies KF, Chesson P, Harrison S, et al. (2005) Spatial heterogeneity explains the scale dependence of the native‐exotic diversity relationship. Ecology 86: 1602–1610.

Doak DF, Bigger D, Harding EK, et al. (1998) The statistical inevitability of stability‐diversity relationships in community ecology. The American Naturalist 151: 264–276.

Elton CS (1958) The Ecology of Invasions by Plants and Animals. London: Methuen.

Eriksson O (1993) The species‐pool hypothesis and plant community diversity. Oikos 68: 371–374.

Flynn DFB, Mirotchnick N, Jain M, Palmer MI and Naeem S (2011) Functional and phylogenetic diversity as predictors of biodiversity‐ecosystem‐function relationships. Ecology 92: 1573–1581.

Fox JW (2013) The intermediate disturbance hypothesis should be abandoned. Trends in Ecology & Evolution 28: 86–92.

Fridley JD, Peet RK, Wentworth TR and White PS (2005) Connecting fine‐ and broad‐scale species‐area relationships of Southeastern US flora. Ecology 86: 1172–1177.

Fridley JD, Peet RK, van der Maarel E and Willems JH (2006) Integration of local and regional species–area relationships from space‐time species accumulation. The American Naturalist 168: 133–143.

Fridley JD, Stachowicz JJ, Naeem S, et al. (2007) The invasion paradox: reconciling pattern and process in species invasions. Ecology 88: 3–12.

Griffin JN, Byrnes JEK and Cardinale BJ (2013) Effects of predator richness on prey suppression: a meta‐analysis. Ecology 94: 2180–2187.

Grime JP (1973) Competitive exclusion in herbaceous vegetation. Nature 242: 344–347.

Gross K and Cardinale BJ (2007) Does species richness drive community production or vice versa? Reconciling historical and contemporary paradigms in competitive communities. The American Naturalist 170: 207–220.

Gross K, Cardinale BJ, Fox JW, et al. (2014) Species richness and the temporal stability of biomass production: a new analysis of recent biodiversity experiments. The American Naturalist 183: 1–12.

Hector A, Schmid B, Beierkuhnlein C, et al. (1999) Plant diversity and productivity experiments in European grasslands. Science 286: 1123–1127.

Hooper DU and Vitousek PM (1997) The effects of plant composition and diversity on ecosystem processes. Science 277: 1302–1305.

Hubbell SP, Foster RB, O'Brien ST, et al. (1999) Light‐gap disturbances, recruitment limitation, and tree diversity in a Neotropical forest. Science 283: 554–557.

Janzen DH (1970) Herbivores and the number of tree species in tropical forests. The American Naturalist 104: 258–261.

MacArthur RH and Wilson EO (1967) The Theory of Island Biogeography. Princeton, NJ: Princeton University Press.

May RM (1972) Will large and complex systems be stable? Nature 238: 413–414.

Miller AD, Roxburgh SH and Shea K (2011) How frequency and intensity shape diversity‐disturbance relationships. Proceedings of the National Academy of Sciences of the United States of America 108: 5643–5648.

Morris WF and Wood DM (1989) The role of lupine in succession on Mount St. Helens: facilitation or inhibition? Ecology 70: 697–703.

Myers JA and Harms KE (2009) Seed arrival, ecological filters, and plant species richness: a meta‐analysis. Ecology Letters 12: 1250–1260.

Paine RT (1966) Food web complexity and species diversity. The American Naturalist 100: 65–76.

Pärtel M, Zobel M, Zobel K and van der Maarel E (1996) The species pool and its relation to species richness: evidence from Estonian plant communities. Oikos 75: 111–117.

Peet RK (1992) Community structure and ecosystem function. In: Glenn‐Lewin DC, Peet RK and Veblen TT (eds) Plant Succession: Theory and Prediction, pp. 103–151. Cambridge, UK: Chapman & Hall.

Peet RK, Palmquist KA and Tessel SM (2014) Herbaceous layer species richness of southeastern forests and woodlands: patterns and causes. In: Gilliam FS and Roberts MR (eds) The Herbaceous Layer in Forests of Eastern North America, 2nd edn, pp. 255–276, chap. 10. Oxford, UK: Oxford University Press.

Roughgarden J, Iwasa Y and Baxter C (1985) Demographic theory for an open marine population with space‐limited recruitment. Ecology 66: 54–67.

Schnitzer SA, Klironomos JN, Hille Ris Lambers J, et al. (2011) Soil microbes drive the classic plant diversity‐productivity pattern. Ecology 92: 296–303.

Seabloom EW, Borer ET, Boucher VL, et al. (2003) Competition, seed limitation, disturbance, and reestablishment of California native annual forbs. Ecological Applications 13: 575–592.

Shmida A and Wilson MV (1985) Biological determinants of species diversity. Journal of Biogeography 12: 1–20.

Stohlgren TJ, Barnett DT, Jarnevich CS, Flather C and Kartesz J (2008) The myth of plant species saturation. Ecology Letters 11: 313–326.

Stromberg JC (2007) Seasonal reversals of upland‐riparian diversity gradients in the Sonoran Desert. Diversity and Distributions 13: 70–83.

Thebault E and Loreau M (2005) Trophic interactions and the relationship between species diversity and ecosystem stability. The American Naturalist 166: E95–E114.

Tilman D (1982) Resource Competition and Community Structure. Princeton, NJ: Princeton University Press.

Tilman D (1997) Community invasibility, recruitment limitation, and grassland biodiversity. Ecology 78: 81–92.

Tilman D, Reich RB, Knops JMH, et al. (2001) Diversity and productivity in a long‐ term grassland experiment. Science 294: 843–845.

Venail PA, Gross K, Oakley TH, et al. (2015) Species richness, but not phylogenetic diversity, influences community biomass production and temporal stability in a re‐examination of 16 grassland biodiversity studies. Functional Ecology 29: 615–626.

Whittaker RH (1972) Evolution and measurement of species diversity. Taxon 21: 213–251.

Wilson JB (2011) The twelve theories of co‐existence in plant communities: the doubtful, the important and the unexplored. Journal of Vegetation Science 22: 184–195.

Wilson JB, Peet RK, Dengler J and Partel M (2012) Plant species richness: the world records. Journal of Vegetation Science 23: 796–802.

Zhang Y, Chen HYH and Reich PB (2012) Forest productivity increases with evenness, species richness and trait variation: a global meta‐analysis. Journal of Ecology 100: 742–749.

Zobel M, van der Maarel E and Dupre C (1998) Species pool: the concept, its determination and significance for community restoration. Applied Vegetation Science 1: 55–66.

Further Reading

Huston MA (1994) Biological Diversity: The Coexistence of Species on Changing Landscapes. Cambridge, UK: Cambridge University Press.

Loreau M, Naeem S and Inchausti P (2002) Biodiversity and Ecosystem Functioning: Synthesis and Perspectives. Oxford, UK: Oxford University Press.

Rosenzweig ML (1995) Species Diversity in Space and Time. Cambridge, UK: Cambridge University Press.

Contact Editor close
Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite close
Brown, Rebecca L, Reilly, Lee Anne J, and Peet, Robert K(Feb 2016) Species Richness: Small Scale. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0020488.pub2]