CHAPTER IV: WILFLIFE HABITATS FOR MISSISSIPPI’S SGCN,

THREATS AND CONSERVATION ACTIONS^179

L acustrine refers to open bodies of freshwater situated in depressions or dammed river channels.

They are also referred to as lentic or standing water systems. These habitats consist of reservoirs, oxbow

lakes, semi-permanent ponds, ephemeral ponds and beaver ponds. In 2004, around 1,450 publicly

owned lakes, reservoirs and ponds (>25 acres) covered approximately 246,000 acres. The largest

reservoirs include flood-control impoundments in the Yazoo Basin and the Ross Barnett Reservoir, a

water supply lake near Jackson.

This type includes five subtypes: 11.1 Oxbow Lakes, 11.2 Reservoirs, 11.3 Artificial Ponds, 11.4

Ephemeral (Temporary) Ponds and 11.5 Beaver Ponds.

GENERAL CONDITION

Unlike most other types, the amount of lentic habitat increases faster than it is lost due to new

construction, especially ponds which increased nearly 13 percent in the last decade. The conditions of

lentic communities vary depending on the intensity of adjacent land uses and their proximity to urban

areas. Lakes are impacted by shoreline alterations or urbanization around larger reservoirs, such as Ross

Barnett Reservoir. Delta oxbows are heavily impacted, primarily due to intensive land use practices.

However, stream channel alterations, levees, deforestation and water diversions impact the natural

progression of oxbow lakes by modifying runoff and accelerating sediment accumulation. Some

oxbows in Mississippi remain natural in form and function such as the 50 oxbows that occur within the

50,000 acre tract of conservation lands in the Deaton Preserve (The Nature Conservancy) and

Pascagoula River and Ward Bayou State Wildlife Management Areas.

Urbanization, pollution and land-use practices have generally increased levels of toxins and nutrients in

lakes. Data collected by the Mississippi Department of Environmental Quality (MDEQ) is being used to

develop nutrient criteria but a preliminary review showed no compelling evidence of impairment in

2004 (formal assessment pending). Currently there are five lake habitats under fish consumption

advisories for mercury or PCB. Although DDT in fish tissue has decreased ten-fold since it was banned

in 1972, levels in the Delta remain among the highest in the nation resulting in an advisory being issued

for the entire Delta in 2001. Nearly 80 percent of the lakes on MDEQ's 303(d) list of impaired waters

are oxbow habitats in the Delta. Common causes for these lakes not meeting their designated use are

pesticides, nutrients and sediments.

11. LACUSTRINE (LENTIC) COMMUNITIES