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Table 3 Results of student's t test for dependent samples

From: Biological traits and community patterns of Trichoptera at two Patagonian headwater streams affected by volcanic ash deposition

  Nant y Fall Chiquito
  t (1.52) Observed relationship t (1.52) Observed relationship
Species richness 4.1** Pre > Post 5.68** Pre > Post
Total density -   4.26** Pre > Post
−2.93* Post > Pre 3.98** Pre > Post
FFG     
Scrapers -   6.87** Pre > Post
Shredders 2.76* Pre > Post 2.83** Pre > Post
Collector-filterers -   2.98* Pre > Post
Predators -   3.43** Pre > Post
Algal piercers -   nd  
  1. Dependent samples examining the effects of volcanic ashfall on species richness, total density, Shannon diversity index (H′), and density of functional feeding groups on the two studied sites (Northwestern Patagonia Argentina). nd, variable non detected on the river. *p < 0.05 and ** p < 0.005.