Brian J. Armitage

HYDROLOGIC VARIABILITY AND THE APPLICATION OF INDEX OF BIOTIC INTEGRITY METRICS TO WETLANDS: A GREAT LAKES EVALUATION

Interest by land-management and regulatory agencies in using biological indicators to detect wetland degradation, coupled with ongoing use of this approach to assess water quality in streams, led to the desire to develop and evaluate an Index of Biotic Integrity (IBI) for wetlands that could be used to categorize the level of degradation. We undertook this challenge with data from coastal wetlands of the Great Lakes, which have been degraded by a variety of human disturbances. We studied six barrier beach wetlands in western Lake Superior, six drowned-river-mouth wetlands along the eastern shore of Lake Michigan, and six open shoreline wetlands in Saginaw Bay of Lake Huron. Plant, fish, and invertebrate communities were sampled in each wetland. The resulting data were assessed in various forms against gradients of human disturbance to identify potential metrics that could be used in IBI development. Our results suggested that the metrics proposed as potential components of an IBI for barrier beach wetlands of Lake Superior held promise. The metrics for Lake Michigan drowned-river-mouth wetlands were inconsistent in identifying gradients of disturbance; those for Lake Huron open embayment wetlands were yet more inconsistent. Despite the potential displayed by the Lake Superior results within the year sampled, we concluded that an IBI for use in Great Lakes wetlands would not be valid unless separate scoring ranges were derived for each of several sequences of water-level histories. Variability in lake levels from year to year can produce variability in data and affect the reproducibility of data collected, primarily due to extreme changes in plant communities and the faunal habitat they provide. Substantially different results could be obtained in the same wetland in different years as a result of the response to lake-level change, with no change in the level of human disturbance. Additional problems included limited numbers of comparable sites, potential lack of undisturbed reference sites, and variable effects of different disturbance types. We also evaluated our conclusions with respect to hydrologic variability and other major natural disturbances affecting wetlands in other regions. We concluded that after segregation of wetland types by geographic, geomorphic, and hydrologic features, a functional IBI may be possible for wetlands with relatively stable hydrology. However, an IBI for wetlands with unpredictable yet recurring influences of climate-induced, long-term high water periods, droughts, or drought-related fires or weather-related catastrophic floods or high winds (hurricanes) would also require differing scales of measurement for years that differ in the length of time since the last major natural disturbance. A site-specific, detailed ecological analysis of biological indicators may indeed be of value in determining the quality or status of wetlands, but we recommend that IBI scores not be used unless the scoring ranges are calibrated for the specific hydrologic history pre-dating any sampling year.

Distribution and abundance of caddisflies (Trichoptera) in the St. Clair-Detroit River system

Abundance and distribution patterns of the caddisflies of the St. Clair-Detroit River system were investigated in 1983–84. Collections of both adults and larvae yielded 70 species representing 34 genera and 12 families. Leptoceridae and Hydroptilidae were the most common families and Ceraclea the most common genus in number of species. This study adds 21 species to the Michigan record. The hydropsychids Cheumatopsyche (81, 63, 105 m−2; log-transformed values for mean and lower and upper 95% C.L.) and Hydropsyche (70, 57, 87 m−2) were the most abundant genera collected as larvae in the St. Clair and Detroit rivers, while Oecetis (41, 35, 47 m−2) was the most abundant in Lake St. Clair. Larval densities of caddisflies in the Detroit River were about twice those in the St. Clair River, but the number of genera collected in each river was about equal (22 vs. 23). Larval abundances were higher in October than May because most genera had substantial overwinter population declines. Low densities and species richness in some areas of the St. Clair-Detroit River system may reflect in part continued water quality problems, but community structure has markedly improved and representation of pollution-sensitive organisms has increased over a 12–15 year period.

Updated checklist of the Michigan (USA) caddisflies, with regional and habitat affinities

Abstract Based on examination of ~180,000 specimens from 695 collections of 443 localities collected from the 1930s to 2015 we report 295 species of caddisflies from Michigan. Of these, 41 are reported from the state for the first time. Another 18 species previously reported from Michigan are listed as doubtful. The 11 most abundant species collectively represented over half of all specimens collected. Conversely, 80 species were known from <10 specimens, and 27 species from a single specimen. The Michigan fauna is similar to those of Minnesota and Ohio, adjacent states with comparable recent collecting effort. Regional and habitat affinities for each Michigan species are reported herein. Due to the high level of species discovery over the last few years, despite a >80-year collecting history, it is likely that additional species remain undiscovered in the state.

A new caddisfly genus (Trichoptera, Odontoceridae) from Vietnam.

Abstract Cephalopsyche, a new genus of caddisfly (Trichoptera, Odontoceridae), is described from Vietnam. Two new species are placed in the genus: Cephalopsyche gorgona sp. n. and Cephalopsyche neboissi sp. n. The adult male and female of each species exhibit distinct sexual dimorphism, especially in head morphology. In males, there are hinged, chamber-like structures on the vertex of the head, containing filamentous, columnar tissue when exposed. Descriptions and illustrations of both species are provided.

A New Species of the Genus Phryganopsyche Wiggins (Trichoptera: Phryganopsychidae) from Vietnam

Abstract Phryganopsychidae (Trichoptera) is a monotypic family found exclusively in Asia. Phryganopsyche wigginsi, new species is described from Vietnam. This is the fourth species recorded for the genus and the second species reported for Vietnam.