TitleEmergence and Flight Activity of Alpine Stream Insects in Two Years with Contrasting Winter Snowpack
Publication TypeJournal Article
Year of Publication2008
AuthorsFinn, DS, Poff, NL
JournalArctic Antarctic and Alpine Research
Volume40
Pagination638-646
Type of ArticleJournal Article
ISSN1523-0430
Abstract

Flight of alpine stream insects has not been well Studied but is all important ecological process that ensures successful mating and allows gene flow among relatively isolated populations. In this Study, we collected actively flying insects along a perpendicular transect from an alpine headwater stream in the Colorado Rocky Mountains (U.S.A.) during, the summer emergence season in two consecutive years with contrasting hydrology: 2002 had minimal snowfall the previous winter, while 2003 snowfall was above average. Flight activity patterns among four common stream taxa were similar to previously reported results from streams below treeline: Ephemeroptera and Plecoptera declined as all inverse power function, Trichoptera declined as a negative exponential function, and Simuliidae did not decrease with lateral distance. Sex ratios typically were strongly biased. possibly a result of the harsh terrestrial environment negatively influencing the naturally more sedentary sex (which varies among taxa). In 2003, the majority of common species emerged approximately one month later than in 2002. and abundance and diversity were greater in 2003 than 2002, patterns potentially attributable to increased snowpack amount and duration. Late-emerging species, by contrast. were less abundant in 2003, likely because that year emergence was delayed to later in the season, when cooler air temperatures reduce flight activity. Our results Suggest that alpine streams are sensitive to interannual variation in snowpack. and therefore more research will be needed to address the potential effects of climate change and associated winter snowfall trends on these unexpectedly diverse aquatic systems.

URL<Go to ISI>://WOS:000261441100004
DOI10.1657/1523-0430(07-072)[finn]2.0.co;2