Land loss in coastal Louisiana (U.S.A.)
Land loss in coastal Louisiana (U.S.A.)
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路易斯安那州沿海地区的土地流失（美国）
DOI：
10.1007/bf01867025
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发表时间：
1979
影响因子：
3.5
通讯作者：
John W. Day
中科院分区：
文献类型：
--
作者：
N. Craig;R. Turner;John W. Day
本文探讨了路易斯安那州沿海湿地损失的原因和后果。土地损失是一种累积影响，是许多自然和人为影响的结果。自然损失是由沉降、废弃河流三角洲的腐烂、波浪和风暴造成的。人为损失是由防洪措施、蓄水、疏浚以及随后对人工渠道的侵蚀造成的。湿地的弃土和土地复垦项目也造成了湿地损失。路易斯安那州沿海地区的土地损失总量至少为 4,300 公顷/年。一些湿地变成了弃土堆和其他生态系统，因此湿地损失可能高出两到三倍。巴拉塔里亚湾盆地每年湿地损失占湿地面积的2.6%。人类活动是土地流失的主要决定因素。如果算上弃土面积，目前因运河直接损失的湿地总面积可能接近10%。水文、土地、植被、底质、沉降、泥沙供给之间的相互关系复杂；然而，运河密度高的水文单元通常与较高的土地流失率相关，并且该速度可能会加快。土地流失的一些累积影响包括海水入侵增加、缓冲风暴影响的能力丧失以及养分大量增加。衡量影响的一项指标是，路易斯安那州每年损失约 8–17 × 106（美国）的渔业产品和服务。从水文单位的层面来看，土地损失超越了当地植被、基质、地质和水文的差异。因此，土地管理应集中在该组织层面。正确的指南建议需要了解湿地河口系统的长期相互关系。
This paper examines causes and consequences of wetland losses in coastal Louisiana. Land loss is a cumulative impact, the result of many impacts both natural and artificial. Natural losses are caused by subsidence, decay of abandoned river deltas, waves, and storms. Artificial losses result from flood-control practices, impoundments, and dredging and subsequent erosion of artificial channels. Wetland loss also results from spoil disposal upon wetlands and land reclamation projects.Total land loss in Louisiana's coastal zone is at least 4,300 ha/year. Some wetlands are converted to spoil banks and other eco-systems so that wetland losses are probably two to three times higher. Annual wetland losses in the Barataria Bay basin are 2.6% of the wetland area. Human activities are the principal determinants of land loss. The present total wetland area directly lost because of canals may be close to 10% if spoil area is included. The interrelationship between hydrology, land, vegetation, substrate, subsidence, and sediment supply are complicated; however, hydrologic units with high canal density are generally associated with higher rates of land loss and the rate may be accelerating.Some cumulative impacts of land loss are increased saltwater intrusion, loss of capacity to buffer the impact of storms, and large additions of nutrients. One measure of the impact is that roughly $8–17 × 106 (U.S.A.) of fisheries products and services are lost annually in Louisiana.Viewed at the level of the hydrologic unit, land loss transcends differences in local vegetation, substrate, geology, and hydrology. Land management should therefore focus at that level of organization. Proper guideline recommendations require an appreciation of the long-term interrelations of the wetland estuarine system.