EARLY HEARING DETECTION AND INTERVENTION VIRTUAL CONFERENCE
MARCH 2-5, 2021
(Virtually the same conference, without elevators, airplane tickets, or hotel room keys)
6/08/2017 | 9:15 AM - 9:30 AM | MECHANISMS OF COTTONWOOD SEEDLING ESTABLISHMENT IN GRAVEL-BED RIVERS, ACROSS A RANGE OF SCALES | 302A
MECHANISMS OF COTTONWOOD SEEDLING ESTABLISHMENT IN GRAVEL-BED RIVERS, ACROSS A RANGE OF SCALES
We propose that currently-accepted models for cottonwood establishment, derived for sandy streams, require modifications in gravel environments due to fundamental physical differences. There is agreement that the master variable driving regeneration and seedling success in western North American gravel-bed rivers is stage, through its effects on water availability. On the Nyack Floodplain of the Flathead River in Montana, we found that at the point scale, two variables determine suitable locations for seedlings to get a continued water supply through their first growth season: (i) a finer matrix, which retains more capillary water, and (ii) the surface gravel layer, acting as “rock mulch” (capillary barrier) to decrease evaporation. At the reach scale, we found that the typically observed arcuate bands of salicaceous trees are not explained by groundwater dynamics, but have a hydraulic fundament: hydrochory. The drift entrains seeds, which start germinating. Turbulent mixing advects some propagules into shallow zones along shorelines, where they deposit and start growing underwater; as stage recedes, the river seeds its own boundaries. Thus, spatial patterns of establishment depend on the drawdown of flow profiles between the beginning and end of the seed availability period.
- C14 Hydroecology
- C28 Land-Water Interfaces
- C16 Restoration Ecology
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Presenters/Authors
Claudio Meier
(), University of Memphis, cimeier@memphis.edu;
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Richard Hauer
(), University of Montana, ric.hauer@umontana.edu;
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