Sydney School of Veterinary Science, Faculty of Science, University of Sydney, Sydney, New South Wales, Australia.
Ellen S. Dierenfeld, LLC, St. Louis, Missouri, United States of America.
PLoS One. 2021 May 19;16(5):e0250857. doi: 10.1371/journal.pone.0250857. eCollection 2021.
Habitat loss and alteration are two of the biggest threats facing insular flying-foxes. Altered habitats are often re-vegetated with introduced or domestic plant species on which flying-foxes may forage. However, these alien food plants may not meet the nutritional requirements of flying-foxes. The critically endangered Christmas Island flying-fox (CIFF; Pteropus natalis) is subject to habitat alteration and the introduction of alien food plants, and therefore is a good model species to evaluate the potential impact of alien plant species on insular flying-foxes. In this study, we evaluated nutritional content of native food plants to determine how flying-foxes historically met their nutritional requirements. Furthermore, we compared the nutritional content of native and alien fruits to predict possible impacts of alien plants on insular flying-foxes. Native and alien fruits and flowers, and native foliage (leaves, petals, and petioles) commonly consumed by the CIFF were collected and evaluated for soluble sugars, crude protein, non-fiber carbohydrates, and nine minerals. Evaluation of native food plants suggests that flying-foxes meet energy requirements by consuming fruit and nectar. However, fruit and nectar are low in protein and essential minerals required for demanding life periods; therefore, flying-foxes likely supplement their diets with pollen and foliage. Thus, flying-foxes require a diverse array of plants to meet their nutritional requirements. Compared to native fruits, alien fruits contained significantly higher non-fiber carbohydrates, and this may provide an important energy source, particularly from species that bear fruit year-round. Median mineral concentrations in alien fruit species, however, were deficient compared to native fruits, suggesting major (or even seasonal) shifts in the proportion of alien species in the CIFF diet could lead to nutritional imbalances. This study confirms the need to quantify nutritional parameters in addition to feeding ecology when evaluating habitat quality to inform conservation actions that can be applied both locally and globally.
生境丧失和改变是面临岛屿狐蝠的两大威胁。改变后的栖息地通常会重新种植外来或家养植物，狐蝠可能会在这些植物上觅食。然而，这些外来食物植物可能无法满足狐蝠的营养需求。极度濒危的圣诞岛狐蝠（CIFF；Pteropus natalis）面临着生境改变和引入外来食物植物的问题，因此是评估外来植物物种对岛屿狐蝠潜在影响的良好模型物种。在这项研究中，我们评估了本地食物植物的营养成分，以确定狐蝠历史上如何满足其营养需求。此外，我们比较了本地和外来水果的营养成分，以预测外来植物对岛屿狐蝠的可能影响。我们收集并评估了 CIFF 常吃的本地和外来水果和花朵，以及本地树叶（叶子、花瓣和叶柄）的可溶糖、粗蛋白、非纤维碳水化合物和九种矿物质的含量。对本地食物植物的评估表明，狐蝠通过食用水果和花蜜来满足能量需求。然而，水果和花蜜的蛋白质和对需求生命阶段至关重要的矿物质含量较低；因此，狐蝠可能会用花粉和树叶来补充饮食。因此，狐蝠需要各种各样的植物来满足其营养需求。与本地水果相比，外来水果含有更高的非纤维碳水化合物，这可能是一个重要的能量来源，特别是对于那些全年都结果的物种。然而，与本地水果相比，外来水果物种的矿物质浓度中位数较低，这表明 CIFF 饮食中外来物种的比例可能会发生重大（甚至季节性）变化，从而导致营养失衡。这项研究证实，在评估栖息地质量以告知保护行动时，除了摄食生态学之外，还需要量化营养参数，这些行动可以在本地和全球范围内实施。
