Alternative Methods for Assessing and Monitoring Mangrove Forests

在全球范围内，红树林为热带和亚热带沿海地区的当地居民提供了一种基本资源。例如，它们提供防止风暴潮的沿海保护，是许多可再生产品的来源，维持着许多贫困社区的生活。从生态上讲，这些湿地是众多水生生物的托儿所，也是候鸟的重要集结地。最近还发现它们是热带地区碳含量最高的森林之一。不幸的是，他们正在经历一些最快的森林砍伐速度，那些剩下的森林往往严重退化。它们消失的一个关键原因是缺乏评估和监测这些森林湿地残留物的方法。红树林通常位于偏远地区，作为潮汐森林，它们极难到达和穿越。因此，我的目标是开发新的方法来远程绘制和监测这些森林。利用可以在夜间获取且不受云层影响的雷达星载卫星图像，我希望开发出准确绘制这些树木的状况(即健康)地图以及提取红树林生物物理参数数据(例如树高、树木密度、生物量)的方法。此外，我希望研究从加拿大无人驾驶航空系统(UAS)收集的图像是否可以单独使用或与雷达数据结合使用，以快速绘制和监测这些受威胁森林的生物物理和生化参数。如果成功，可以迅速部署这些平台，以评估急性原因(如漏油、海啸)对红树林的影响。由于大多数红树林位于发展中国家，很少对红树林进行昂贵的地面调查，因此几乎没有历史记录。因此，我还建议使用历史和当前的卫星图像来研究红树林丧失和退化的空间模式，并利用支持它们的大河流的现有水文数据。实际上，旱地引水工程的长期间接影响可能是它们目前消亡的一个主要原因。最后，我还建议测试从红树林年轮和/或从其中收集的同位素数据是否可以用来追踪过去的扰动，从而将观察到的红树林损失或退化与原因联系起来。有了这些数据，资源管理者可以最好地减轻对红树林的进一步破坏，并选择最合适的恢复手段。

Globally, mangrove forests provide an essential resource to local inhabitants of coastal regions of the tropics and the subtropics. For example they provide coastal protection from storm surges and are a source of numerous renewable products that sustain many impoverished communities. Ecologically, these wetlands act as a nursery for numerous aquatic organisms and are crucial staging areas for migratory birds. They have also recently been found to be among the most carbon-rich forests of the tropics. Unfortunately, they are experiencing some of the fastest rates of deforestation and those forests that remain are often severely degraded. A key reason for their loss is a lack of methods for assessing and monitoring what remains of these forested wetlands. Mangroves are often located in remote regions and as tidal forests they are extremely difficult to access and to traverse. Consequently, I aim to develop new methods for remotely mapping and monitoring these forests. Employing radar space-borne satellite imagery, which can be acquired at night and is not inhibited by cloud cover, I hope to develop means for accurately mapping the condition (i.e. health) of these trees as well as for extracting mangrove biophysical parameter data (e.g. tree height, tree density, biomass). In addition, I hope to examine whether imagery collected from Canadian Unmanned Aerial Systems (UAS) can be used alone or in conjunction with the radar data to rapidly map and monitor biophysical and biochemical parameters of these threatened forests. If successful, these platforms could be quickly deployed to assess impacts to mangroves from acute causes (e.g. oil spills, tsunamis). Since the majority of mangroves are located in developing countries, expensive ground surveys of mangroves are rarely conducted and thus historical records are almost non-existent. Consequently, I also propose to use historical and current satellite imagery to examine spatial patterns of mangrove loss and degradation with available hydrological data from large rivers that sustain them. Chronic indirect impacts from upland water diversion projects may in fact be a major reason for their current demise. Finally, I also propose to test whether mangrove tree rings and/or isotope data collected from them can be used to track past perturbations thus linking observed mangrove loss or degradation to causal agents. With these data, resource managers can best mitigate further damage to the mangroves and select the most appropriate means for restoration.