scholarly journals Diversity–disturbance relationships: frequency and intensity interact

2012 ◽  
Vol 8 (5) ◽  
pp. 768-771 ◽  
Author(s):  
Alex R. Hall ◽  
Adam D. Miller ◽  
Helen C. Leggett ◽  
Stephen H. Roxburgh ◽  
Angus Buckling ◽  
...  
Keyword(s):  
Species Diversity ◽  
Empirical Evidence ◽  
Empirical Studies ◽  
Ecological Theory ◽  
Intermediate Disturbance Hypothesis ◽  
Intermediate Disturbance ◽  
Disturbance Frequency ◽  
Theoretical Predictions ◽  
Experimental Populations ◽  
Disturbance Hypothesis

An influential ecological theory, the intermediate disturbance hypothesis (IDH), predicts that intermediate levels of disturbance will maximize species diversity. Empirical studies, however, have described a wide variety of diversity–disturbance relationships (DDRs). Using experimental populations of microbes, we show that the form of the DDR depends on an interaction between disturbance frequency and intensity. We find that diversity shows a monotonically increasing, unimodal or flat relationship with disturbance, depending on the values of the disturbance aspects considered. These results confirm recent theoretical predictions, and potentially reconcile the conflicting body of empirical evidence on DDRs.

Modelling wave-induced disturbance in highly biodiverse marine macroalgal communities: support for the intermediate disturbance hypothesis

2008 ◽  
Vol 59 (6) ◽  
pp. 515 ◽  
Author(s):  
Phillip R. England ◽  
Julia Phillips ◽  
Jason R. Waring ◽  
Graham Symonds ◽  
Russell Babcock
Keyword(s):  
Species Diversity ◽  
Wave Model ◽  
Intermediate Disturbance Hypothesis ◽  
Curvilinear Relationship ◽  
Total System ◽  
Physical Disturbance ◽  
Stochastic Disturbance ◽  
Intermediate Disturbance ◽  
Wave Induced ◽  
Disturbance Hypothesis

As biodiversity declines globally, it is becoming increasingly important to understand the processes that create and maintain biodiverse communities. We examined whether the extraordinarily high species diversity of macroalgal communities in shallow coastal waters off south-west Western Australia is related to wave-induced physical disturbance. We used the numerical wave model SWAN to estimate the hydrodynamic forces generated by waves in bathymetrically complex coastal reefs. Oscillatory water motion at the seabed during extreme wave events was used as an index of physical disturbance in macroalgal communities. There was a significant curvilinear relationship between species diversity and disturbance index, consistent with the intermediate disturbance hypothesis (IDH). Diversity was lower at exposed offshore sites where disturbance is likely to be highest and at very sheltered sites with the least disturbance. Our results match those from some other highly diverse habitats, including rainforests, grasslands and coral reefs in which patchy, stochastic disturbance regimes have been hypothesised to prevent the development of homogeneous climax communities, promoting spatiotemporal heterogeneity and increasing total system diversity. Our results represent important evidence in support of a role for the IDH in driving diversity in marine plant communities.

Predicting plant species diversity in response to disturbance magnitude in grassland remnants of central Alberta

2002 ◽  
Vol 80 (5) ◽  
pp. 504-511 ◽  
Author(s):  
K Vujnovic ◽  
R W Wein ◽  
M R.T Dale
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Exotic Species ◽  
Plant Species ◽  
Intermediate Disturbance Hypothesis ◽  
Plant Species Diversity ◽  
Small Scale ◽  
Intermediate Disturbance ◽  
Total Species Richness ◽  
Disturbance Hypothesis

The Intermediate Disturbance Hypothesis states that the greatest species diversity occurs at intermediate levels of disturbance because species coexistence is maintained at a nonequilibrium state and no strong competitor can dominate completely. On the other hand, diversity of exotic species is expected to increase with the disturbance magnitude. These patterns were tested for in this study. The cover of all vascular plants, mosses, and lichens in 1 × 1 m plots across a range of disturbance levels was sampled in 11 remnant grasslands within the Aspen Parkland Ecoregion of central Alberta, western Canada. The Intermediate Disturbance Hypothesis was supported for small-scale within-patch diversity for total species richness and Simpson's diversity index. Lower species diversity was found in undisturbed and lightly grazed as well as in highly disturbed plots. Intermediate levels of disturbance had reduced dominance of Festuca hallii (Vasey) Piper and increased abundance of most other species; this gave the highest species diversity. The species richness and diversity of exotic plant species showed a significant positive relationship with the magnitude of the disturbance. Understanding relationships between disturbance and plant species diversity, especially exotic plants, can influence management decisions on what disturbance regime is conducive to maintaining natural plant communities.Key words: Intermediate Disturbance Hypothesis, diversity, exotic species, grassland.

scholarly journals Patterns of tree diversity in response to logging in Algonquin Provincial Park

SURG Journal ◽  
2011 ◽  
Vol 4 (2) ◽  
pp. 56-62 ◽  
Author(s):  
Brittany Jones ◽  
Olivia Molenda ◽  
Colin Hayward ◽  
Mark D'Aguiar ◽  
Nathan Miller ◽  
...  
Keyword(s):  
Species Diversity ◽  
Intermediate Disturbance Hypothesis ◽  
Tree Species Diversity ◽  
Natural Systems ◽  
Intermediate Disturbance ◽  
Suitable Amount ◽  
The Impact ◽  
Intermediate Amount ◽  
Provincial Park ◽  
Disturbance Hypothesis

The acceleration of human disturbance on natural systems necessitates the understanding of the effects of disturbance on species diversity, in order to mitigate its impacts. The Intermediate Disturbance Hypothesis (IDH) provides a general framework for predicting how these effects will unfold, centered on the premise that diversity will be maximized at intermediate levels of disturbance, or after an intermediate amount of time has passed since the last disturbance. We investigated the impact of disturbance by logging in Algonquin Provincial Park, ON, Canada, on tree species diversity. We sampled 7 sites, with known times since the last logging event, ranging between 4 and 149 years. We found that species richness and diversity indeed peaked at an intermediate disturbance regime of approximately 80 years since logging. We also found that this maximum diversity was caused by a combination of early, pioneer, post-pioneer, sub-climax, and climax species. Our experiment shows that IDH is applicable to the mixed forests of Algonquin, and therefore, provided that sites are logged after a suitable amount of time has passed, it is possible to harvest trees and maintain diversity.

A phytoplankton community in a temperate reservoir in New South Wales, Australia: relationships between similarity and diversity indices and measures of hydrological disturbance

2005 ◽  
Vol 56 (2) ◽  
pp. 203 ◽  
Author(s):  
Tsuyoshi Kobayashi ◽  
Brian G. Sanderson ◽  
Geoff N. G. Gordon
Keyword(s):  
Phytoplankton Community ◽  
New South ◽  
Diversity Indices ◽  
Intermediate Disturbance Hypothesis ◽  
Species Number ◽  
Intermediate Disturbance ◽  
Consecutive Sampling ◽  
South Wales ◽  
Cell Densities ◽  
Disturbance Hypothesis

Temporal changes in diversity and similarity of a phytoplankton community were investigated in relation to external hydrological disturbance in the Ben Chifley reservoir from September 1998 to January 2002. Species richness varied by a factor of 4–5 at each of three sites studied during the period (n = 53 at each site). Species diversity (measured using Simpson’s D and Shannon–Wiener’s H, based on primarily genus or species number and cell densities) varied by a factor of 8–10, whereas similarity between two consecutive sampling dates (measured using Hurlbert’s index and Pinkham and Pearson’s B) varied by a factor of 10–46. When diversity was measured with H, it had an approximate quadratic (convex) relationship with similarity, as measured with Hurlbert’s index. However, diversity was seldom related to external hydrological disturbance (measured as intensity and variability of daily inflow rates between two consecutive sampling dates). Similarity was significantly and negatively related to disturbance variability. These results suggest that the mechanisms that regulate diversity and similarity may differ from each other, and question the usefulness of observed approximate quadratic relationships between similarity and diversity indices when assessing the effect of disturbance on diversity. Such relationships may therefore not provide support for Connell’s (1978) intermediate disturbance hypothesis.

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