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重要的资源。例如，它们为海岸提供了抵御风暴潮的保护，是许多可再生产品的来源，维持着许多贫困社区的生计。从生态学上讲，这些湿地是许多水生生物的苗圃，也是候鸟的重要集结地。它们最近也被发现是热带地区碳含量最高的森林之一。不幸的是，它们正经历着一些速度最快的森林砍伐，而那些保留下来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剩余情况的方法。红树林通常位于偏远地区，作为潮汐林，很难进入和穿越。因此，我的目标是开发远程测绘和监测这些森林的新方法。利用可在夜间获取且不受云层遮挡的雷达星载卫星图像，我希望开发出准确绘制这些树木状况（即健康状况）以及提取红树林生物物理参数数据（例如树高、树密度、生物量）的方法。此外，我希望研究从加拿大无人机系统（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，这些平台可以迅速部署，以评估急性原因（如石油泄漏、海啸）对红树林的影响。由于大多数红树林位于发展中国家，很少进行昂贵的红树林地面调查，因此几乎不存在历史记录。因此，我还建议利用历史和当前的卫星图像，结合维持红树林的大河的现有水文数据，研究红树林丧失和退化的空间格局。事实上，高原调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，我还建议测试从它们收集的红树林年轮和/或同位素数据是否可以用于跟踪过去的扰动，从而将观察到的红树林损失或退化与因果因素联系起来。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，并选择最适当的恢复方法。

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.