+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Excess positive associations in communities of intestinal helminths of bats: a refined null hypothesis and a test of the facilitation hypothesis

Excess positive associations in communities of intestinal helminths of bats: a refined null hypothesis and a test of the facilitation hypothesis

Journal of Parasitology 80(3): 398-413

The null hypothesis that the number of positive pairwise covariances should equal the number of negative pairwise covariances in samples from communities of randomly associated helminth species was reevaluated. The proportion of positive covariances in a sample from a community of independent species depends upon the proportion of rare species (prevalence less than 10%), the proportion of common species (prevalence greater than 90%), and the size of the sample of hosts. If rare species dominate, then there will be an excess of negative associations; if common species dominate there will be an excess of positive associations. Many helminth communities have more rare than common species, therefore samples from communities that show an equal number of positive and negative covariances have a greater number of positive associations than is expected for randomly associated species. Increased sample size will reduce the sampling bias, but at least 100 hosts are necessary and often 500-7,500 hosts are required. The excess of positive covariances between helminth species in 10 populations of bats disappeared after restricting the analyses to hosts in which both members of a species pair were present. This result suggests that excess positive associations between helminth species in bats are due to joint presences and absences in hosts rather than to interspecific facilitation. Interspecific facilitation would be supported by observed positive correlations between the intensities of individuals of the species pairs.

Please choose payment method:

(PDF emailed within 0-6 h: $19.90)

Accession: 031354448

Download citation: RISBibTeXText

PMID: 8195942

DOI: 10.2307/3283411

Related references

The role of positive and negative interspecific associations in the organization of communities of intestinal helminths of bats. Parasitology 103 Pt 1: 127-138, 1991

When the topology-dependent permutation test (T-PTP) for monophyly returns significant support for monophyly, should that be equated with (a) rejecting a null hypothesis of nonmonophyly, (b) rejecting a null hypothesis of no structure, (c) failing to falsify a hypothesis of monophyly, or (d) none of the above?. Systematic Biology 45: 0-6, 1996

Dilemma of null hypothesis in ecological hypothesis's experiment test. Ying Yong Sheng Tai Xue Bao 27(6): 2031-2038, 2016

Null hypothesis in studies on plant communities i. null model research procedure statistical analysis of results. Ekologia polska 36(3-4): 471-484, 1988

In praise of value judgments in null hypothesis testingand of "accepting" the null hypothesis. American Psychologist 53(7): 797-798, 1998

Failing to reject the null hypothesis does not mean that the null hypothesis is true. Anesthesia and Analgesia 100(6): 1868-9; Author Reply 1869, 2005

Recruitment-driven, spatially discontinuous communities: a null model for transferred patterns in target communities of intestinal helminths. Journal of Parasitology 81(1): 12-24, 1995

Beyond the null hypothesis--do the HERS results disprove the estrogen/coronary heart disease hypothesis?. American Journal of Cardiology 85(8): 1015-1017, 2000

What role should null-hypothesis significance tests have in statistical education and hypothesis falsification?. Trends in Ecology and Evolution 22(9): 445-6; Author Reply 446, 2007

Perspectives on the Use of Null Hypothesis Statistical Testing. Part II: Is Null Hypothesis Statistical Testing an Irregular Bulk of Masonry?. Educational and Psychological Measurement 77(4): 613-615, 2017

Refining the Stress-Gradient Hypothesis for Competition and Facilitation in Plant Communities. Journal of Ecology 97(2): 199-205, 2009

Refining the stress-gradient hypothesis for competition and facilitation in plant communities. Journal of Ecology 97(2): 199-205, 2009

Equivalence of competitors in plant communities: a null hypothesis and a field experimental approach. American journal of botany 70(7): 1098-1104, 1983

Species-area relations of communities on intertidal boulders: testing the null hypothesis. Journal of Biogeography 11(5): 439-456, 1984

Equivalence Of Competitors In Plant Communities: A Null Hypothesis And A Field Experimental Approach. American Journal of Botany 70(7): 1098-1104, 1983