Comparative analysis of glacial and nival streamflow regimes with implications for lotic habitat quantity and fish species richness

Abstract

Growing interest in the differential responses of glacial and nival rivers to climatic forcing, and in ecological distinctions between the two streamflow regimes, suggests the need for a better comparative understanding of how the annual hydrologic cycle differs with presence or absence of catchment glacial cover. In this study, timing and magnitude characteristics of the average annual hydrographs of five glacierized and four nival catchments in the southwestern Canadian subarctic are empirically identified and compared. Likely effects upon fish habitat are qualitatively assessed, and net fisheries potential is tentatively investigated using taxa richness data. The chief hydrological conclusions at P < 0.05 using Kolmogorov-Smirnov and empirical orthogonal function analyses are: (1) catchment glacial cover results in freshets that are longer, larger, and peak later than those experienced by the nival regime; (2) the winter baseflows of glacial rivers are also much higher on a unit-catchment-area basis; and (3) basin scale and degree of catchment glacial cover are of comparable importance in determining the magnitude of the annual hydrologic cycle. These differences arise from the greater availability, both in volume and over time, of meltwater in glacial catchments, which in part reflects the consistently negative alpine glacial mass balances observed both in the present study area and globally under historical climatic warming. Such regime distinctions result in increased spawning season and winter aquatic habitat availability, which may in turn offset negative habitat characteristics previously identified for glacial river ecosystems. While previous studies have suggested that glacial influences tend to decrease macroinvertebrate diversity and increase salmon populations, preliminary analysis of available fish species presence/absence data from the current study area tentatively appears to suggest similar or, perhaps, slightly higher fish taxa richness relative to nival streams; in all three cases, however, catchment lake cover may play a key hydroecological modifying role. The results strongly confirm and extend existing understanding of glacial-nival regime differences with respect to both streamflow and fisheries ecology, and raise new questions for future research.

Modulation of linear and nonlinear hydroclimatic dynamics by mountain glaciers in Canada and Norway: Results from information-theoretic polynomial selection

“…Alpine glaciers and ice fields lie at the hydrologic heart of many of these mountain ranges, impressing a distinct signature upon water quantity, water quality and freshwater and coastal marine ecosystems (e.g. Ward 1994;Dorava and Milner 2000;Fleming 2005;Mark et al 2005;Hood and Berner 2009;Neal et al 2010;Jacobsen et al 2012). Due to orographic precipitation and glacial melt, mountain headwaters often make inordinately large contributions to the flow of large rivers, and typically impart hydrological and biogeochemical signals that are clearly observable far downstream (e.g.…”

Glacier-mediated streamflow teleconnections to the Arctic Oscillation

“…This includes the Kluane and Wheaton, which deviated substantially from their peers in EOF analysis results based on data from all months of the year. Note that although winter baseflow variability can have some ecological implications (see Fleming, 2005 and references therein), in general the summer freshet is the most important streamflow season in cold regions in terms of both pragmatic water resource impacts and hydroclimatic information content. Winter temperatures in the study area are sufficiently low that essentially all winter precipitation falls, and is stored until spring, as snow, regardless of year-to-year winter temperature fluctuations.…”

“…Edgington, 1995;Manly, 1997) modelling. Although used by Fleming (2004Fleming ( , 2005, the details of the procedure have not previously been documented in the open literature. The j th mode is considered significant if its observed eigenvalue satisfies the following condition:…”

Implementation of an eco-hydrological classification in Chilean rivers

“…The Source of Flow factor acts at a mesoscale level, indicating the stream fl ow is originated by rainfall, snowmelt, glaciers or a combination of these (Fleming 2005, Snelder et al 2004. This controlling factor has its origin from the topography of the watershed (Snelder et al 2002) considering how this impacts on fl ow regime.…”