The Latitudinal Gradient in Geographical Range: How so Many Species Coexist in the Tropics

Stevens, George

doi:10.1086/284913

Cited by 1,630 publications

(1,942 citation statements)

References 59 publications

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“…Increased seasonality may also increase the range of climatic conditions that species experience, promoting evolution of greater climatic tolerances and enabling species to breed over larger areas. Assuming equal dispersal abilities, species from aseasonal areas may thus more frequently disperse to areas where they can survive, but not breed, inflating species richness (Stevens, 1989). Evidence suggests that species from aseasonal environments have narrower climatic tolerances (e.g.…”

Section: (2 ) Seasonalitymentioning

confidence: 99%

Species–energy relationships at the macroecological scale: a review of the mechanisms

2005

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Correlations between the amount of energy received by an assemblage and the number of species that it contains are very general, and at the macro-scale such species-energy relationships typically follow a monotonically increasing curve. Whilst the ecological literature contains frequent reports of such relationships, debate on their causal mechanisms is limited and typically focuses on the role of energy availability in controlling the number of individuals in an assemblage. Assemblages from high-energy areas may contain more individuals enabling species to maintain larger, more viable populations, whose lower extinction risk elevates species richness. Other mechanisms have, however, also been suggested. Here we identify and clarify nine principal mechanisms that may generate positive species-energy relationships at the macro-scale. We critically assess their assumptions and applicability over a range of spatial scales, derive predictions for each and assess the evidence that supports or refutes them. Our synthesis demonstrates that all mechanisms share at least one of their predictions with an alternative mechanism. Some previous studies of species-energy relationships appear not to have recognised the extent of shared predictions, and this may detract from their contribution to the debate on causal mechanisms. The combination of predictions and assumptions made by each mechanism is, however, unique, suggesting that, in principle, conclusive tests are possible. Sufficient testing of all mechanisms has yet to be conducted, and no single mechanism currently has unequivocal support. Each may contribute to species-energy relationships in some circumstances, but some mechanisms are unlikely to act simultaneously. Moreover, a limited number appear particularly likely to contribute frequently to species-energy relationships at the macro-scale. The increased population size, niche position and diversification rate mechanisms are particularly noteworthy in this context.

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Section: (2 ) Seasonalitymentioning

confidence: 99%

Species–energy relationships at the macroecological scale: a review of the mechanisms

2005

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“…Across a range of spatial scales, and for a wide spectre of taxonomic groups, it has been documented that average species richness within a sampling area of a given size increase when moving from high to low latitudes (Stevens 1989;Gaston 1996Gaston , 2000Witman et al 2004). Many hypotheses have been put forward to explain the observed patterns but few causal relationships have been identified (Pianka 1966;Gaston 2000;Hillebrand 2004;Jablonski et al 2006;Harrison and Cornell 2007;Buckley et al 2010).…”

Section: Introductionmentioning

confidence: 99%

A high local species richness and biodiversity within high-latitude calcareous aggregates of tube-building polychaetes

Haanes

Gulliksen

2011

Biodivers Conserv

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In general, biodiversity and species richness follow the latitudinal diversity gradient and decrease from the tropics towards the poles. Exceptions have however been recorded, as for deep coldwater coral reefs at high latitudes, which comprise biodiversity hotspots. Here we assess and characterise the high-latitude (69°N) species richness and diversity of a local shallow-water fauna associated with small calcareous aggregations of a serpulid polychaete. A dense and very species rich fauna was recorded within aggregations of Filograna implexa Berkeley, 1828. Totally 4663 individuals belonging to 99 species (61 solitary, 38 colonial) were recorded in a total aggregation volume of only 4.4 l covering an area less than 0.05 m 2 of a wreck situated in a tidal stream in North Norway. The number of species within each aggregation was positively related to its size, indicating that the high species diversity may be due to structural heterogeneity, which increase with aggregation size and probably creates new microhabitats and protect against predation. We present a species list including abundance and biomass, pin-point common species and describe a method for sampling such faunas associated with calcareous structures.

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“…Water temperature is an easily measurable parameter and an excellent indicator of changes in ecological and environmental conditions (LAEVASTU & HAYES 1981). The temperature range of an area is also correlated with latitude, increasing from lower to middle and high latitudes, tropical to sub-tropical and temperate environments (STEVENS 1989). Moreover, the temperature is positively correlated with species diversity of a habitat, indicating a latitudinal gradient of species diversity, well documented for marine and terrestrial assemblages of animals (see STEVENS 1989).…”

Section: Discussionmentioning

confidence: 93%

“…The temperature range of an area is also correlated with latitude, increasing from lower to middle and high latitudes, tropical to sub-tropical and temperate environments (STEVENS 1989). Moreover, the temperature is positively correlated with species diversity of a habitat, indicating a latitudinal gradient of species diversity, well documented for marine and terrestrial assemblages of animals (see STEVENS 1989). Comparing the diversity of fish species in different estuaries along the north-south coast of the Western Atlantic, VIEIRA & MUSICK (1993) observed that lower latitudes (tropical estuaries) tend to have more species and more equitability among them than temperate and subtropical areas.…”

Section: Discussionmentioning

confidence: 99%

Behavioral patterns and movement intensity of Sotalia guianensis (P. J. van Bénéden) (Cetacea, Delphinidae) in two different areas on the Brazilian coast

et al. 2007

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The behavioral patterns of the estuarine dolphin, Sotalia guianensis (P. J. van Bénéden, 1864), were compared between two populations along the Brazilian coast: Caravelas (Bahia), along the eastern coast, and Norte Bay (Santa Catarina), along the southern coast. Applying the focal-group sampling in both areas, information such as the geographic position (UTM) of groups and predominant behavioral patterns were obtained. Geographic positions were used to calculate the total distance traveled by estuarine dolphin groups on each observation day. Since the distance traveled varies with time, the daily mean speed of the dolphin’s group was used as an index of movement intensity. Two comparable and easily recognizable behavioral patterns were considered: travelling and foraging. Overall movement intensity and behavioral pattern frequency were similar between both areas. However, a seasonal variation was observed in both parameters in Norte Bay, while in Caravelas these parameters were homogeneous throughout the year. Variation in the behavior of the estuarine dolphin was consistent with variations in environmental factors, such as water temperature.

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The Latitudinal Gradient in Geographical Range: How so Many Species Coexist in the Tropics

Cited by 1,630 publications

References 59 publications

Species–energy relationships at the macroecological scale: a review of the mechanisms

Species–energy relationships at the macroecological scale: a review of the mechanisms

A high local species richness and biodiversity within high-latitude calcareous aggregates of tube-building polychaetes

Behavioral patterns and movement intensity of Sotalia guianensis (P. J. van Bénéden) (Cetacea, Delphinidae) in two different areas on the Brazilian coast

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