ABSTRACT: Paleoecology of an early Holocene wetland on the Canadian Prairies.

CGRG Bibliography of Canadian Geomorphology
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Abstract

A plant macrofossil record from the glacial Lake Hind basin is used to reconstruct early postglacial wetland plant succession and paleohydrology. Between >10.6 and 9.1 ka BP, there are four plant assemblage zones: (1) an early (>10 ka BP) zone dominated by Cyperaceae and aquatics; (2) a subsequent (~10.6-10.1 ka BP) with emergents (Menyanthes trifoliata, Potentilla palustris, Scripus validus) and fewer acquatic plants; (3) an interval between ~ 10.1 and 9.8 ka BP dominated by Drepanocladus aduncus; and (4) a zone between ~9.1 and 0.1 ka BP with Menyanthes trifoliata and Equisetum. These data indicate a gradual decline in water depth between 10.6 and 10.1 ka BP due to deepening of one or more outlets of glacial Lake Hind. From ~10.6 and 10.1 ka BP, the importance of Menyanthes records pronounced, seasonal flooding. Furthermore, lack of evidence for complete drawdown and terrestrialization in the basin - despite local and regional evidence for postglacial warming - indicates that this wetland was minimally impacted by climate change up until at least 9.1 ka BP. Persistence of very wet conditions locally is consistent with recent results from south-central Saskatchewan, and may be due to release of meltwater from stagnant ice. However, frequent low-energy flooding of the basin by the Souris River is more plausible. In general, the apparent insensitivity of acquatic habitats to abrupt climate change is some locales on the Canadian Prairies demonstrates the potential long-term mitigating effects of local hydrological factors.

Bibliography of Canadian Geomorphology