The description of Caribbean seagrass communities in Dominica, West Indies and their response to anthropogenic and natural disturbances

The world's seagrasses are in peril with nearly 1/5 th of global seagrass cover having been lost in the past two decades due to human impacts. Further, the mean rate of loss for seagrasses globally is higher than that for tropical forests and Indo-Pacific coral reefs. The loss of seagrasses is projected to continue with the rates accelerating in south-east Asia and the Caribbean. The largest impacts to seagrass meadows in the tropics are extensive sediment discharge as a result of modification to the terrestrial landscape and destructive or unsustainable fishing practices. More scientific exploration is warranted in these areas given growing anthropogenic impacts and paucity in the characterization of the local seagrass habitats. Relative to Florida or Panama, few studies have been conducted on seagrass meadows in the Lesser Antilles with studies often having very different measures. On the Caribbean island of Dominica, seagrass data is absent. One of the greatest hurdles in formulating global policies designed to protect and sustain seagrass habitats is the lack of monitoring or simply estimates of seagrass cover in many parts of the world.;My dissertation sets out to identify and describe the essentially unknown seagrass resources of the Caribbean island of Dominica, use observations and experiments to quantify the impact of several natural and anthropogenic disturbances on the native seagrass populations, and generate an inclusive assessment of this marine habitat that can be used as a baseline for both current management discussions and future comparative studies. At present, there are significant gaps in information about Dominica's marine benthic habitats, yet status reports continue to be written without supporting field data and these reports shape local environmental policy.;This dissertation paints the first comprehensive picture of Dominica's seagrass resource in terms of its distribution, diversity, and the local pressure that shape it. At the broader Caribbean perspective, this dissertation describes seasonal patterns within seagrass beds that lack the climax seagrass species T. testudinum and quantified the impacts of aggressive invasive seagrass Halophila stipulacea as it increases its distribution across the region. Lastly, within the scope of disturbance ecology, this dissertation contrasts the relative spatial extent and severity of several natural and anthropogenic impacts. This dissertation was my attempt to use a combination of empirical and observational studies to examine the seagrass ecosystem from local, narrow events all the way up to broad, encompassing ecological concepts. Hence the findings of this dissertation are not only of value to stakeholders in Dominica, but also to those in the wider Caribbean region and to scientists in the broader field of marine ecology.