Chance and determinism in the development of isolated communities

Ward, S. A.; Thornton, I. W. B.

doi:10.1046/j.1365-2699.2000.00196.x

Cited by 55 publications

(31 citation statements)

References 29 publications

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“…However, available data do not allow any conclusions to be drawn about the comparative dispersion ability of the three species. In isolated ecosystems (as lakes and temporary ponds) also stochastic processes, for example the order of arrival of colonising species ("priority effects"), may play an important role in determining the structure of natural communities (Blaustein & Margalit 1996;Wilbur 1997;Ward & Thornton 2000).…”

Section: Discussionmentioning

confidence: 99%

Distribution and ecology of calanoid species in relation to morphometric and chemical characteristics of lakes and ponds of the Northern Apennines (Italy)

Tavernini¹,

Fratta²,

Sartore³

et al. 2003

J Limnol

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Section: Discussionmentioning

confidence: 99%

Distribution and ecology of calanoid species in relation to morphometric and chemical characteristics of lakes and ponds of the Northern Apennines (Italy)

Tavernini¹,

Fratta²,

Sartore³

et al. 2003

J Limnol

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“…Under extreme conditions, priority effects ͑Eriksson and Eriksson 1998͒ may produce novel species assemblages ͑cf. Roozen and Westhoff 1985;Facelli and D'Anela 1990;del Moral and Wood 1993;Ward and Thornton 2000͒. Within-plot similarity does indeed decline with distance from sources and with elevation. This effect recalls long-term studies of small islands in a Swedish lake ͑Rydin and Borgegård 1991͒, where similarity increased over time, but where further development appeared arrested because dominant trees have failed to reach the islands.…”

Section: Similaritymentioning

confidence: 97%

Gradients in compositional variation on lahars, Mount St. Helens, Washington, USA

Moral

Ellis

2005

Plant Ecol

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How isolation affects primary succession remains unresolved. Our hypotheses are: 1͒ the rate of succession is slowed within 50 m from sources and 2͒ dominance increases more rapidly if the growing season is longer. We sampled lahar vegetation near conifer forests on Mount St. Helens 23 years after the eruption using transects ͑Muddy͒ and grids ͑Butte Camp, BC͒. Transects were compared to isolated plots of the same age, while grids were compared to vegetation that was 400 years older. Cover declined with distance and with elevation on the Muddy due to denser seed rain near forests and shorter growing seasons at higher elevation. On BC-1, next to a forest, richness measures increased with distance, while cover decreased with elevation. On BC-2, more exposed than BC-1, mean richness and cover declined with elevation, but increased towards seed sources. Equitability increased with distance and with elevation on more stressful transects and on BC-1. Percent similarity ͑PS͒, a measure of floristic heterogeneity, declined with elevation on Muddy-SW. BC-1 PS decreased with both distance and elevation. Data from grids collected since 1987 showed that both sites became more homogeneous through time. Directional changes on BC-1 were greater than on BC-2, while annual variation of DCA scores declined only on BC-2. These differences are related to conifer dominance patterns. Succession is influenced by isolation, which controls the seed rain, and by stress, which controls establishment, the rate of biomass accumulation, and the spread of immigrants. Although community development is governed by environmental factors, this study shows that the effects of dispersal that result from distance factors can persist and may be a source of unexplained variation in mature communities.

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“…Beside the long debate on equilibrium and non equilibrium hypotheses (see Naselli-Flores et al, 2003), some studies on assembly rules revealed that the structure of a community may depend on a priority effect (Ward & Thornton, 2000) modulated by complex hierarchical factors (Rodrigo et al, 2009). Hierarchy theory is a formal approach to the complex influences of scale, and suggests that different phenomena (e.g.…”

Section: Introductionmentioning

confidence: 99%

Does lake age affect zooplankton diversity in Mediterranean lakes and reservoirs? A case study from southern Italy

et al. 2010

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Zooplankton assemblages of 51 lacustrine\ud environments located in the middle of the Mediterranean Region were analysed to evaluate the existence of an ‘age effect’ in determining their structure.\ud The analysed datasets refer to two different geographic areas, one comprising 30 natural and artificial lakes in Sicily and the other an arrangement of 21 analogous aquatic ecosystems located at the bottom of the Italian Peninsula, a more pristine area called Southern Apennine region. Most of the natural lakes are of post-glacial origin. The artificial lakes in both datasets were built in the last century and offer the\ud opportunity to evaluate the possible short-term effects of ageing on the structure of their zooplankton. A\ud comparison of assemblages in the two regions by PERMANOVA and nMDS revealed that they are\ud quite different; therefore they were analysed separately.\ud An explorative analysis on the possible\ud relationship between biological data and environmental data (including lake age) was performed on both datasets using DISTLM. The presence of an ‘age effect’ emerged only in the subset of artificial lakes of the Southern Apennine region; accordingly it was\ud tested more in detail with an a posteriori PERMANOVA analysis in the subset of reservoirs that resulted positive in the first test. SIMPER allowed us to single out the main species responsible of changes in the zooplankton along the selected age groups. No age effect was evident in the Sicilian water bodies, where other variables, such as conductivity, trophic state, urbanisation and water level fluctuations proved to have a major role in shaping zooplankton assemblages. The results showed that the age effect is: (i) detectable only at a time scale of decades; (ii) masked by the human impact in the\ud watershed

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Chance and determinism in the development of isolated communities

Cited by 55 publications

References 29 publications

Distribution and ecology of calanoid species in relation to morphometric and chemical characteristics of lakes and ponds of the Northern Apennines (Italy)

Distribution and ecology of calanoid species in relation to morphometric and chemical characteristics of lakes and ponds of the Northern Apennines (Italy)

Gradients in compositional variation on lahars, Mount St. Helens, Washington, USA

Does lake age affect zooplankton diversity in Mediterranean lakes and reservoirs? A case study from southern Italy

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