Models of stream habitat characteristics associated with tubificid populations in an intermountain watershed

Abstract

Habitat assessments were conducted in an intermountain watershed at three spatial extents to explore ways to predict the presence of tubificid oligochaetes likely to support the parasite Myxobolus cerebralis, cause of salmonid whirling disease. Stream reaches with six different reach slope characteristics were selected using GIS. The aquatic habitat in 60 reaches selected at random was measured and classified into distinct habitat units. Within the habitat units, areas of microhabitat with depositional fine sediments were chosen, measured, and core samples were removed to characterize the sediments and benthic oligochaetes. Two tubificids, Tubifex spp. and Limnodrilus hoffmeisteri, were abundant and co-occurred in silt-clay and fine sand sediments in these habitats. Models were posed and tested to predict the presence and relative abundance of tubificids using habitat characteristics from the three spatial extents: reach, habitat unit, and microhabitat. At the reach extent, tubificids were associated with low-reach slope and with slow water habitats. Within habitat units, tubificids were associated with higher percentages of fine sediments and higher stream width:depth ratios. In microhabitat cores, the presence of silt-clay sediments was positively associated with higher average stream width:depth ratios. Since ecological relationships are often scale dependent and stream systems have a natural hierarchy, predictive habitat models such as these that use measures from several scales may help researchers and managers more efficiently identify and quantify aquatic communities at highest risk of infection by the M. cerebralis parasite.

Spawning Behavior of Mountain Whitefish and Co‐occurrence of Myxobolus cerebralis in the Blackfoot River Basin, Montana

“…Infection rates ranged from 0% to 100% in the tributaries occupied by mountain whitefish as well as a pattern of high TAM exposure (67-76% of group scores ≥ grade 3) throughout the main stem of the Blackfoot River. This variation among streams conforms to a basin-scale pattern of increasing infection in the downstream direction (Pierce et al 2009), as broadly observed across the Intermountain West (Sandell et al 2001;de la Hoz Franco and Budy 2004;Anlauf and Moffitt 2008). In our study area, the low-elevation presence of M. cerebralis largely overlaps with the distribution of mountain whitefish with the exception of the Clearwater River, which flows through a series of glacially formed lakes as well as cold, rocky, basin-fed, forested streams with low levels of fine instream sediment, such as Gold Creek and the North Fork Blackfoot River.…”

Influences of habitat type and environmental variables on benthic macroinvertebrate communities in a large shallow subtropical lake (Lake Taihu, China)

“…S1A, available online). Previous studies have demonstrated that species of Tubificidae prefer living in silt-clay and fine sand sediments (Anlauf and Moffitt, 2008) and selectively feed on finer particles less than 63 mm in diameter (Rodriguez et al, 2001;Anlauf and Moffitt, 2008). In contrast, fine sediment can significantly reduce the survivorship of gastropods and bivalves by limiting their feeding behaviors (Donohue and Irvine, 2003;Schmidlin and Baur, 2007).…”

Community structure and decadal changes in macrozoobenthic assemblages in Lake Poyang, the largest freshwater lake in China

“…Furthermore, fine sediment and suspended particles can significantly reduce the survival of unionids by restricting their feeding behaviors (Donohue and Irvine, 2003). In contrast, species of Annelida prefer living in mud and fine sand sediments and selectively feed on finer organic particles (Anlauf and Moffitt, 2008). Substrate stability is important for mussel habitats, and a positive relationship between substrate stability and mussel abundance has been observed in several studies (Allen and Vaughn, 2010;Johnson and Brown, 2000).…”