| Geoscience and Environment |
Background
Overview of the Endla Mire Complex
The Endla Nature Reserve was
established in 1985 and rules were strengthened in 1997 to protect several
ecological niches: freshwater lakes, swamp forest, mixed forest and rivers,
and grassy, treeless peatland. The site provides a refuge for endangered
flora and fauna. The area insures recharge of local acquifers in Ordovician
dolomitic limestone overlain by moraines (gravel and sand), lake sediments
and peat bogs more than 7 meters (22 feet) deep. RAMSAR Summary
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The Topographic Basis for the Complex
The bedrock topography
and glacial deposits in the eastern central part of Estonia form poorly drained
depressions that lead to the formation of lakes and bogs. "Four drumlin fields
in Estonia are located behind bedrock elevations where the glacier advanced
down-slope (Saadjärve, Kolga-Jaani), or in lowland conditions in marginal
areas of depressions." Maris Rattas and Volli Kalm. CLASSIFICATION AND AREAL DISTRIBUTION OF GLACIOTECTONIC FEATURES IN ESTONIA, Geological Quarterly, 1999, 43(2):177-182.
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Glaciation
During the Pleistocene Period, which lasted up to 10,000
years ago, Estonia was affected by successive advances and retreats of continental
glaciers. At the edges of the glaciers meltwater formed vast lakes and rivers
depositing gravel, sand, and clay. In some places the bedrock topography
favored the formation of shallow, poorly-drained depressions bounded by hills
formed of glacial deposits. See maps of Baltic glaciatation.
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Impact of Topography
In a landscape with poor drainage small
variations in topography may have a greater impact on plant, animal, and
human activities than where drainage systems are naturally well-developed.
Ecologists have developed interesting models that show how plant and animal
communities adjust to changes in the environment. Geographers, sociologists,
and historians have shown how changes in the environment can lead to human
migration and cultural change.
Formerly, impact studies led some investigators to propose the theory that
human behavior is determined by environmental factors. However, today the
concern is otherwise: that human behavior is leading to environmental change
with the potential for undesirable consequences, including extinction of
many species of plants and animals as well as health hazards for humans.
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