Intm Distrb Hyp. Spr 98

BIBLIOGRAPHY THE EFFECT OF PHYSICAL DISTURBANCE ON ECOLOGICAL COMMUNITIES (INCLUDING THE INTERMEDIATE DISTURBANCE HYPOTHESIS) Kateri A. Harrison

Bornette, G., and C. Amoros. 1996. Disturbance Regimes and Vegetation Dynamics: Role of Floods in Riverine Wetlands. Journal of Vegetation Science. 7: 615-622.

• The authors studied whether the frequency of flood disturbance had an affect on the succession of riparian vegetation along tributaries of the Rhone River in France. I thought their analysis and interpretation of their data was flawed because even though the tributaries has similar diversity index values, the authors concluded that the tributary with the intermediate amount of disturbance had the highest diversity.
Boulton, A.J., C.G. Peterson, N.B. Grimm, and S.G. Fisher. 1992. Stability of an Aquatic Macroinvertebrate Community in a Multiyear Hydrologic Disturbance Regime. Ecology. 73: 2192-2207. • This study looks at the effect of droughts and floods on the succession and community composition of macroinvertebrates living in an Sonoran desert stream. I liked this paper because it seems like the authors were very honest and clearly admitted that some of their original predictions just weren't true. This paper has a very good bibliography if you are interested in learning more about this topic.
Clark, J.S. 1991. Disturbance and Tree Life History on the Shifting Mosaic Landscape. Ecology 72: 1102-1118. • This paper studies the interaction between a disturbance regime and the life history of forest trees. Life history factors discussed include: age at maturity, fecundity, longevity, and reproductive period. In this article, the author defines "intermediate disturbance frequency" as that which implies the optimum life history that coincides with the life histories of the greatest number of species in the system. I liked this article much better than the next one by the same author.
Clark, J.S. 1991. Disturbance and population structure on the shifting mosaic landscape. Ecology 72: 1119-1137. • The author presents a discussion of tree population dynamics and structure in relationship to the shifting mosaic hypothesis and disturbance frequency. In this case, the author defines "intermediate disturbance frequency" as that which maximizes the probability of being reproductively mature at the time of the next disturbance event. An interesting theoretical model predicting the effect of various types of disturbance (mostly fires and tree fall gaps) on the population dynamics of tree species is presented. This paper, unfortunately, does not provide any new data nor any analysis of data. I think a lot more research into this area is needed before this model is accepted. However, the article is widely cited in the disturbance literature.
Collins, S.L. 1987. Interaction of Disturbances in Tallgrass Prairie: A Field Experiment. Ecology. 68: 1243-1250. • This well written article presents the results of a 2-year field experiment in an Oklahoma Tallgrass prairie. It examines the interaction of 2 types of disturbances, fire and cattle grazing. One interesting conclusion is that simple models (i.e.. those that only look at one type of disturbance), such as the intermediate disturbance hypothesis, cannot address the variable interactions among disturbances in communities with complex disturbance regimes. To analyze their data, the authors used familiar statistical tests like the t-test and ANOVA. So the results were easy for me to interpret. Overall, I really liked this article.
Connell, J.H. 1978. Diversity in Tropical Rain Forests and Coral Reefs. Science. 199:1302-1310. • The author was a professor at UCSB and an advisor to W.P. Sousa when this article was published. Here Connell lays the theoretical groundwork for the intermediate disturbance hypothesis. His studies of tropical rainforest trees in Africa and of corals in Australia are used as examples in this paper. Dr. Connell provides many ideas for future testing of the intermediate disturbance hypothesis. However, this article does not provide a significant amount of data nor a rigorous test of the hypothesis. Overall, the article was well written and is the beginning of a debate that continues till today.
Dunson, W.A., and J. Travis. 1991. The role of Abiotic Factors in Community Organization. The American Naturalist. 138: 1067-1091. • This article begins by providing a really good overview of the debate by ecologists as to whether abiotic or biotic factors are the primary force structuring communities. The authors then describe a theoretical model of the type of experiment one could perform to test this question. Their model does not seem very practical to me, but it is an interesting approach. The authors then modify their model and use it to perform lab experiments on 3 species of related fish at various salinity levels. They found that the 3 species of fish had different physiological tolerances to salt and that these differences affect their interactions when they are forced to compete with each other. The authors then describe how steep gradients of physiochemical factors could lead to the evolution of new species. One complaint that I have about this article is that it studies just one group of organisms (fish) along one physical gradient (salinity). Overall, I thought this was a very well written and interesting article.
Hobbs, R.J., and L.F. Huenneke. 1992. Disturbance, Diversity, and Invasion: Implications for Conservation. Conservation Biology. 6: 324-337. • This interesting review article focuses on the role of disturbance in grasslands. The authors generally seem to support the intermediate disturbance hypothesis. However, they focus on the more applied questions such as maintaining the historical disturbance regime in conservation areas. Overall, this article is easy to read and understand, but it is not very analytical. Also, since it is a review article, it does not provide any new data. However, it does provide a nice overview of the literature.
Kubota, Y. 1995. Effects of Disturbance and Size Structure on the Regeneration Process in a Sub-boreal Coniferous Forest, Northern Japan. Ecological Research. 10: 135-142. • Typhoons are the major type of disturbance affecting the National Park which was the study site for this article. The author's findings suggests that natural disturbances may regulate the regeneration process in the future by affecting the mortality and growth patterns of understory trees.
Palmer, M.A., P. Arensburger, P.S. Botts, C.C. Hakenkamp, and J.W. Reid. 1995. Disturbance and the community Structure of Stream Invertebrates: Patch-Specific Effects and the Role of Refugia. Freshwater Biology. 34: 343-356. • Flooding is the major disturbance studied in this northern Virginian stream. The authors analyzed species composition of the chironomid and copepod communities before, during, and after flood events. Multi-variate statistical techniques were used to analyze the data. The authors found that responses to disturbance are very complex. I thought this was an informative article.
Pickett, S.T.A., J. Kolasa, J.J. Armesto, and S.L. Collins. 1989. The Ecological Concept of Disturbance and its Expression at Various Hierarchical Levels. Oikos. 54:129-136. • This paper seeks to provide ecologists with more precise definitions of disturbance, disturbance regimes, and stress. The authors also incorporate a lot of information on the hierarchical scale of ecosystems. This is a conceptual paper and a model of ecological hierarchy is provided. However, no data is provided or analyzed. Overall, I thought this paper was kind of boring.
Sanders, H.L. 1968. Benthic Marine Diversity: a Comparative Study. American Naturalist 102:243-82. • This very well written article presents Sander's Stability-Time Hypothesis. He also provides a methodology for measuring diversity and he compares it with other methods. Benthic marine samples were collected from various sites in India and New England. Overall, I think it is definitely worthwhile to read this paper. It is one of the best articles listed in this bibliography.
Saxon, E.C. 1990. Disturbance Regimes in North Queensland Rainforests: A Re-evaluation of Their Relationship to Species Richness and Diversity. Australian Journal of Ecology. 15:241-244. • This article compares the effects of natural disturbances such as landslides and fires to a human-created disturbance, logging, in an Australian rainforest. The authors found that species richness remains substantially lower for a long time after a site has been logged. While this article does nothing to advance ecological theory regarding disturbance, it does have value for those interested in applied or conservation biology. Overall, it was very concise and well written.
Schwilk, D.W., J.E. Keeley, and W.J. Bond. 1997. The Intermediate Disturbance Hypothesis does not Explain Fire and Diversity Pattern in Fynbos. Plant Ecology. 132:77-84. • Fynbos are a shrub community found in the Mediterranean climate of South Africa. The authors measured species diversity and community heterogeneity at low, intermediate, and high fire frequency and at various spatial scales. They found that the intermediate disturbance hypothesis did not seem to hold true at any of the spatial scales they studied. They evaluated their data using several non-parametric statistical tests with which most of us are familiar with including the Mann Whitney test and the Kruskal-Wallace test. Overall, I thought the paper was very interesting.
Sousa, W.P. 1979. Disturbance in Marine Intertidal Boulder Fields: The Non-equilibrium Maintenance of Species Diversity. Ecology 60:1225-1239. • This was one of the articles we read in class for my presentation. This study is very well known. Sousa's work was influenced by that of Sanders 1968 and Connell 1978. As we discussed in class, this study has a couple of flaws and in hindsight does not appear to offer the unequivocal support for the intermediate disturbance hypothesis that most ecologists once thought it did. Specifically, Sousa's data shows that the small, fixed boulders rapidly regained and then surpassed their natural diversities. When the experiment ended, the small boulders had even exceeded the diversities of the medium boulders. His conclusions are also confounded by the relatively small sample size for intermediate sized boulders. Sousa also looked at another site called Leo Carrillo State Beach. He doesn't talk about it much, but on page 1235 he does say that the large boulders had the highest diversity.
Sousa, W.P. 1980. The Responses of a Community to Disturbance: The Importance of Successional Age and Species' Life Histories. Oecologia. 45: 72-81. • The author tested various aspects of seaweeds growing on boulders in the rocky intertidal zone in Santa Barbara County. Groups of boulders containing algae assemblages at various successional stages were overturned to mimic the natural wave disturbances caused by storms. The changes in species composition, recovery to the original species composition and the assemblage's resistance to disturbance were all measured and analyzed. The author found that each successional stage differed in its response to disturbance primarily as a result of the physiological adaptations of individual species. Overall, I thought this article was very good.
Townsend, C.R., A.G. Hildrew, and K. Schofield. 1987. Persistence of Stream Invertebrate Communities in Relation to Environmental Variability. Journal of Animal Ecology. 56: 597-613. • This study focused on benthic invertebrates at twenty-seven stream sites in southern England. Censussing was conducted twice, eight years apart, but over a very large region. In this study, a sort of biotic disturbance occurred with the introduction of a fish, Cottus gobio L. into two previously fishless area. The authors could not detect a significant change in persistence of the invertebrate community in the two sites with fish compared to the other sites without fish introductions. Although this study was not groundbreaking in any way, I thought it was interesting.
Townsend, C.R., M.R. Scarsbrook, and S. Doledec. 1997. The Intermediate Disturbance Hypothesis, Refugia, and Biodiversity in Streams. Limnology and Oceanography. 42: 938-949. • This is one of the articles we read in class for my presentation. Townsend performed a field experiment on the Intermediate Disturbance Hypothesis and looked for refugia in 27 New Zealand stream tributaries. Townsend suspected that some of the 27 sites received more disturbance than others, thereby setting up a disturbance gradient between the sites. His results are interesting, and those sites with the intermediate intensity of disturbance generally had the highest species richness. However, there appears to be a small sample size at the lower intensities. Also, the confidence limits on some the regression equations seem to be high. Also, the author did not provide a correlation analysis for the relationship between taxon richness and frequency of disturbance. The lines on his graph merely connect the average values. So this paper doesn't really convince me that the intermediate disturbance hypothesis is correct.
Westman, W. 1980. Gaussian Analysis: Identifying Environmental Factors Influencing Bell-Shaped Species Distributions. Ecology. 61: 733-739. • I read this article when I first began my literature research on the role of various abiotic factors have on community structure, so it has a much broader focus than some of the other articles listed in this bibliography assignment. Westman studied coastal sage scrub vegetation in southern California. He tested 40 environmental factors to determine which factors control the range and distribution of species. Total soil nitrogen, light penetration to ground level, distance from the coast, soil magnesium, and slope aspect were among the environmental factors tested. Disturbances such as grazing, fire, and air pollution were also tested. The main focus of the article is a statistical technique called Gaussian Analysis. The author found that Gausssian Analysis will not identify all of the important environmental factors influencing a species distribution, but it will identify some of the important factors which are not found by other more traditional statistical techniques. The author also provides a nice concise introduction to the individualistic hypothesis which was developed by Gleason and Whittaker. Overall, I enjoyed reading this article.
Wilson, J.B. 1994. The 'Intermediate Disturbance Hypothesis' of Species Coexistence is Based on Patch Dynamics. New Zealand Journal of Ecology. 18: 176-181. • I had to read this paper several times before I could figure out what the heck the author was trying to say. Basically, there seems to be an argument between this author, Wilson, and another scientist named Padisak. They are debating whether the intermediate disturbance hypothesis applies to between-patch dynamics or if it applies to within-patch dynamics and should therefore be called gradual climate change. If you are interested in patch dynamics or how metapopulations are affected by disturbance, then this paper would be good to read.
Wootton, J.T., M.S. Parker, and M.E. Power. 1996. Effects of Disturbance on River Food Webs. Science. 273: 1558-1561. • This concise and well written article describes the results of experiments performed on the naturally flooding Eel River and on a dammed (flooding prevented) Mad River. Both rivers are in northern California. The authors found that natural flooding allows longer food chain lengths and therefore more species richness. The dammed river had shorter food chain lengths because predatory resistant grazing insect populations were able to increase, thereby diverting energy away from the food chain leading to predatory fish. Overall, I would highly recommend this article to anyone interested in learning more about disturbances.