Is the Geographic Range of Mangrove Forests in the Conterminous United States Really Expanding?
Is the Geographic Range of Mangrove Forests in the Conterminous United States Really Expanding?
复制标题
DOI：
10.3390/s16122010
复制
发表时间：
2016-12-01
期刊：
影响因子：
3.9
通讯作者：
Long, Jordan
中科院分区：
文献类型：
--
作者：
Giri, Chandra;Long, Jordan
红树林物种在其历史地理范围内外的分布和丰富程度的变化可能对它们提供的生态系统货物和服务产生深远的影响。据信，由于极端寒冷事件的频率和严重程度降低，美国大陆（CONUS）的红树林正在向极地（北方）扩张，而海平面上升是当地红树林向陆地扩张的一个因素。我们使用了类似于35年的卫星图像和美国本土的原位观测，并报告说：（一）红树林向极地扩张是不确定的，现在可能已经停滞，（二）向陆地扩张正在积极发生在历史上最北端的限制。我们发现，佛罗里达东西海岸沿着的红树林的最北纬度界限，除了路易斯安那州和得克萨斯州没有系统地向极点扩展。然而，红树林面积从1980年到2015年在历史最北边界内扩大了4.3%，其中德克萨斯州和佛罗里达南部的变化百分比最高。造成这一变化的因素包括：海平面上升、有无低于冰点的温度、土地使用变化、蓄水/疏浚、水文变化、火灾、风暴、沉积和侵蚀以及种植红树林。此外，海平面上升，相对温和的冬季和近几十年来没有低于冰点的温度可能使局部扩张成为可能。结果突出了一套复杂的强迫作用在红树林的北部范围，并强调需要长期监测，因为这个系统的重要性增加，以适应海洋上升和减轻大气二氧化碳增加的影响。
Changes in the distribution and abundance of mangrove species within and outside of their historic geographic range can have profound consequences in the provision of ecosystem goods and services they provide. Mangroves in the conterminous United States (CONUS) are believed to be expanding poleward (north) due to decreases in the frequency and severity of extreme cold events, while sea level rise is a factor often implicated in the landward expansion of mangroves locally. We used similar to 35 years of satellite imagery and in situ observations for CONUS and report that: (i) poleward expansion of mangrove forest is inconclusive, and may have stalled for now, and (ii) landward expansion is actively occurring within the historical northernmost limit. We revealed that the northernmost latitudinal limit of mangrove forests along the east and west coasts of Florida, in addition to Louisiana and Texas has not systematically expanded toward the pole. Mangrove area, however, expanded by 4.3% from 1980 to 2015 within the historic northernmost boundary, with the highest percentage of change in Texas and southern Florida. Several confounding factors such as sea level rise, absence or presence of sub-freezing temperatures, land use change, impoundment/dredging, changing hydrology, fire, storm, sedimentation and erosion, and mangrove planting are responsible for the change. Besides, sea level rise, relatively milder winters and the absence of sub-freezing temperatures in recent decades may be enabling the expansion locally. The results highlight the complex set of forcings acting on the northerly extent of mangroves and emphasize the need for long-term monitoring as this system increases in importance as a means to adapt to rising oceans and mitigate the effects of increased atmospheric CO2.