REPEAT PHOTOGRAPHY OF LAKE MICHIGAN COASTAL DUNES: EXPANSION OF VEGETATION AND HUMAN IMPACTS SINCE 1900

Abstract Coastal dunes are experiencing increases in vegetation cover and reduced mobility levels in many sites around the world. Ecology-led approaches to coastal dune management perceive this change as ‘undesirable’ because the increase in plant cover leads to a reduction in partially vegetated to bare sand habitats and the species depending on them. This has generated a shift in the management paradigm where the objective is to revert this trend by intervening in the landscape, with actions ranging from re-introducing grazing and mowing, to mechanical removal of dune form and vegetation (dune ‘rejuvenation’). In some cases, such as many coastal dunes in Britain, this has also led to low controls on visitor pressure and allowing/promoting human trampling as a ‘natural’ way to free up areas of bare sand. This commentary critically analyses the main principles (and terminology) underlying this relatively recent shift in management paradigm, and questions assumptions such as ‘bare sand is good’ and/or ‘mobility is natural’ in the context of dune evolutionary cycles and responses to abiotic and biotic drivers. We review the limitations and dangers of this approach and argue that it is not sustainable given the current climatic and environmental conditions, and that it can increase the risk of coastal erosion and force dune systems to deviate from adapting and changing to direct/indirect drivers. Finally, we present the benefits of a management approach that focuses on minimizing human impacts so that natural processes continue to occur.

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The Holland Paleosol: an informal pedostratigraphic unit in the coastal dunes of southeastern Lake Michigan

Canadian Journal of Earth Sciences ◽

10.1139/e04-071 ◽

2004 ◽

Vol 41 (11) ◽

pp. 1385-1400 ◽

Cited By ~ 19

Author(s):

Alan F Arbogast ◽

Randall J Schaetzl ◽

Joseph P Hupy ◽

Edward C Hansen

Keyword(s):

Lake Michigan ◽

Sand Dunes ◽

Coastal Dunes ◽

Buried Soils ◽

Coastal Sand Dunes ◽

Radiocarbon Dates ◽

Long Period ◽

Sand Supply ◽

Buried Soil ◽

Coastal Sand

A very prominent buried soil crops out in coastal sand dunes along an ~200 km section of the southeastern shore of Lake Michigan. This study is the first to investigate the character of this soil informally described here as the Holland Paleosol by focusing on six sites from Indiana Dunes National Lakeshore north to Montague, Michigan. Most dunes in this region are large (>40 m high) and contain numerous buried soils that indicate periods of reduced sand supply and comcomitant stabilization. Most of these soils are buried in the lower part of the dunes and are thin Entisols. The soil described here, in contrast, is relatively well developed, is buried in the upper part of many dunes, and formed by podzolization under forest vegetation. Radiocarbon dates indicate that this soil formed between ~3000 and 300 calibrated years BP. Pedons of the Holland Paleosol range in development from thick Entisols (Regosols) with ABwBCC horizonation to weakly developed Spodosols (Podzols) with AEBsBwBCC profiles. Many profiles have overthickened and (or) stratified A horizons, indicative of slow and episodic burial. Differences in development are mainly due to paleolandscape position and variations in paleoclimate among the sites. The Holland Paleosol is significant because it represents a relatively long period of landscape stability in coastal dunes over a broad (200 km) area. This period of stability was concurrent with numerous fluctuations in Lake Michigan. Given the general sensitivity of coastal dunes to prehistoric lake-level fluctuations, the soil may reflect a time when the lake shore was farther west than it is today. The Holland Paleosol would probably qualify as a formal pedostratigraphic unit if it were buried by a formal lithostratgraphic or allostratigraphic unit.

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Coastal Dune Habitats

Ecology ◽

10.1093/obo/9780199830060-0161 ◽

2016 ◽

Author(s):

Thomas E. Miller ◽

Marina Lauck

Keyword(s):

Lake Michigan ◽

Sand Dunes ◽

Economic Value ◽

Coastal Dunes ◽

High Water ◽

Plant Succession ◽

Environmental Research ◽

Dynamic Topography ◽

Ecological Value ◽

Sea Levels

Coastal dunes occur along the majority of coastlines worldwide, often as parts of barrier islands, and are one of the most dynamic areas on earth. Sufficient supply of sand and strong onshore winds create a dynamic topography of building dunes near the shoreline and often a system of older dunes and troughs further inland. Coastal dunes have significant economic value for, among other things, tourism and fishing, as they protect inland areas from storms and high-water events. They also have critical ecological value, as they provide habitat for many animals, especially nesting seabirds, and shelter- sensitive oyster and seagrass beds in bays, as well as wetlands, and marshes from intense storms. Some of the earliest studies of plant succession, such as Cowles work in 1899, “The ecological relations of the vegetation on the sand dunes of Lake Michigan,” were conducted on coastal dunes and remain prominent for environmental research—especially as sea levels rise and human-related disturbances increase.

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