TY - JOUR

T1 - The influence of geology and season on macroinvertebrates in Belizean streams

T2 - implications for tropical bioassessment

AU - Carrie, Rachael

AU - Dobson, Michael

AU - Barlow, Jos

PY - 2015/6

Y1 - 2015/6

N2 - Considerable attention has been paid to the potentially confounding effects of geological and seasonal variation on outputs from bioassessments in temperate streams, but our understanding about these influences is limited for many tropical systems. We explored variation in macroinvertebrate assemblage composition and the environmental characteristics of 3(rd)- to 5(th)-order streams in a geologically heterogeneous tropical landscape in the wet and dry seasons. Study streams drained catchments with land cover ranging from predominantly forested to agricultural land, but data indicated that distinct water-chemistry and substratum conditions associated with predominantly calcareous and silicate geologies were key determinants of macroinvertebrate assemblage composition. Most notably, calcareous streams were characterized by a relatively abundant noninsect fauna, particularly a pachychilid gastropod snail. The association between geological variation and assemblage composition was apparent during both seasons, but significant temporal variation in compositional characteristics was detected only in calcareous streams, possibly because of limited statistical power to detect change at silicate sites, or the limited extent of our temporal data. We discuss the implications of our findings for tropical bioassessment programs. Our key findings suggest that geology can be an important determinant of macroinvertebrate assemblages in tropical streams and that geological heterogeneity may influence the scale of temporal response in characteristic macroinvertebrate assemblages.

AB - Considerable attention has been paid to the potentially confounding effects of geological and seasonal variation on outputs from bioassessments in temperate streams, but our understanding about these influences is limited for many tropical systems. We explored variation in macroinvertebrate assemblage composition and the environmental characteristics of 3(rd)- to 5(th)-order streams in a geologically heterogeneous tropical landscape in the wet and dry seasons. Study streams drained catchments with land cover ranging from predominantly forested to agricultural land, but data indicated that distinct water-chemistry and substratum conditions associated with predominantly calcareous and silicate geologies were key determinants of macroinvertebrate assemblage composition. Most notably, calcareous streams were characterized by a relatively abundant noninsect fauna, particularly a pachychilid gastropod snail. The association between geological variation and assemblage composition was apparent during both seasons, but significant temporal variation in compositional characteristics was detected only in calcareous streams, possibly because of limited statistical power to detect change at silicate sites, or the limited extent of our temporal data. We discuss the implications of our findings for tropical bioassessment programs. Our key findings suggest that geology can be an important determinant of macroinvertebrate assemblages in tropical streams and that geological heterogeneity may influence the scale of temporal response in characteristic macroinvertebrate assemblages.

KW - biomonitoring

KW - assemblage composition

KW - temporal and spatial effects

KW - Neotropics

KW - Mesoamerica

KW - FRESH-WATER

KW - BENTHIC MACROINVERTEBRATES

KW - NEOTROPICAL STREAMS

KW - COMMUNITY STRUCTURE

KW - INVERTEBRATE DRIFT

KW - SPATIAL-PATTERNS

KW - LIFE-HISTORY

KW - ASSEMBLAGES

KW - VARIABILITY

KW - LANDSCAPE

U2 - 10.1086/681541

DO - 10.1086/681541

M3 - Journal article

VL - 34

SP - 648

EP - 662

JO - Freshwater Science

JF - Freshwater Science

SN - 2161-9549

IS - 2

ER -