How Colonization Time Influences Macroinvertebrate Community Measures on Artificial Substrates

Abstract

ABSTRACT We examined how duration of sampling period affected macroinvertebrate community characteristics measured with artificial substrate samplers in a New Jersey stream. During spring 2001 sixty Hester-Dendy multiplate samplers were deployed in riffle and pool habitats at three locations along a stretch of Lower Merrill Creek. Duplicate samplers were recovered at each habitat weekly over two to six weeks. Abundance varied by an order of magnitude over the study but generally increased with time (20–250 invertebrates/sampler). Pooled taxonomic richness ranged from 8 to 25 taxa/sample. Simpson's Diversity (D) for riffles ranged from 0.58 to 0.91 (mean=0.81±0.06 SE), while pool diversity was less variable (0.83–0.95) and 10% higher (mean=0.88±0.01), Shannon Diversity was generally higher than D, more so in riffle habitats (12%) than in pool habitats (8.6%). While these artificial substrates present a more time- and energy-intensive means to assess macroinvertebrates than some other techniques (e.g., kick or dip nets), they can be used to generate quantitative and detailed stream community information. Based on our results, a five-week colonization period is optimal for using Hester-Dendy substrate samplers.