Florida Manatee Synoptic Aerial Survey 1991-2019

Original provider:
Florida Fish and Wildlife Conservation Commission - Fish and Wildlife Research Institute

Dataset credits:
Florida Fish and Wildlife Conservation Commission - Fish and Wildlife Research Institute

Abstract:
The word “synoptic” means presenting a general view of the whole. The current manatee synoptic survey is a count of manatees over a broad area. The Florida Fish and Wildlife Conservation Commission (FWC) uses these surveys to obtain a general count of manatees statewide. The FWC coordinates an interagency team that conducts the synoptic surveys from one to three times each year (weather permitting). The synoptic surveys are conducted in winter and cover all of the known wintering habitats of manatees in Florida. The survey is conducted to meet Florida state statute 370.12 (4), which requires an annual, impartial, scientific benchmark census of the manatee population. From 1991 through 2011, the counts have been conducted 27 times. These statewide, interagency surveys are currently conducted during the coldest weather of the year (January through March) when manatees move to warm-water sites, such as natural springs, thermal discharges from power and industrial plants, and deep canals. The ideal conditions for the current synoptic survey are cool weather, following a prolonged period of cold weather (usually following multiple cold fronts), low winds, and bright sunshine. Weather conditions and manatee behavior during the survey have a large effect on the synoptic counts. For that reason, the counts are used as indicators of relative abundance within a year and are not suitable for assessing long-term population trends. Counts can vary depending on whether it is warm or cold, sunny or cloudy, calm or windy. Manatees are more easily counted a few days after a cold front when it is slightly warmer, clear, and windless. A warming trend with sunny, windless conditions following cold weather increases the likelihood that manatees will be resting at the water's surface, where observers can easily spot them.

原始提供方：佛罗里达鱼类与野生动物保护委员会-鱼类与野生动物研究所
数据集归属：佛罗里达鱼类与野生动物保护委员会-鱼类与野生动物研究所
摘要：
“综观（synoptic）”一词意为呈现整体的概览。本次海牛综观调查是对大范围区域内的海牛开展计数工作。佛罗里达鱼类与野生动物保护委员会（Florida Fish and Wildlife Conservation Commission，以下简称FWC）依托此类调查获取全州范围内的海牛种群总体数量。该委员会协调跨机构团队，每年开展1至3次综观调查（天气条件允许的前提下）。
综观调查于冬季实施，覆盖佛罗里达州内所有已知的海牛越冬栖息地。本次调查旨在符合佛罗里达州法规第370.12条第4款的要求，该条款规定需对海牛种群开展年度、公正的科学基准普查。1991年至2011年间，此类跨机构全州范围调查共开展27次。当前此类调查于每年最冷时段（1月至3月）开展，此时海牛会迁移至暖水域栖息地，包括天然泉眼、电力与工业电厂的温排水区域以及深水运河。
本次综观调查的理想气象条件为：经历长期低温天气（通常伴随多股冷锋过境）后的凉爽天气、低风速与晴朗日照。调查期间的天气条件与海牛行为对综观计数结果影响显著。正因如此，此类计数仅可作为单年度内种群相对丰度的指示指标，不适用于评估长期种群趋势。计数结果会随气温冷暖、晴阴状况与风速大小产生波动。在冷锋过境数日后，天气转暖、晴朗无风时，海牛更易被观测计数。低温天气过后伴随晴朗无风的回暖天气，会提升海牛在水面休憩的概率，便于观测者识别。