Tidal salt marshes face numerous pressures that threaten their ecological integrity, and many salt marsh vertebrates have exhibited declines concomitant with the degradation of salt marsh habitats. We studied nest survival of MacGillivray’s seaside sparrow Ammospiza maritima macgillivraii and Worthington’s marsh wren Cistothorus palustris griseus in smooth cordgrass Spartina alterniflora and black needlerush Juncus roemerianus dominated salt marshes in northeast Florida, USA, during 2015−2017 to understand why both species have undergone range contractions. We evaluated the effects of tides, habitat features, and weather on nest survival. The probability of a nest surviving from laying to fledging young was low for both species (seaside sparrow: 0.03, 95% CI: 0.00, 0.10; marsh wren: 0.10, 95% CI: 0.04, 0.18), suggesting that nest survival may limit population growth. The most substantial threat to marsh wren and seaside sparrow nest survival was from greater than normal high tides. However, there was limited evidence of direct nest loss due to flooding. An analysis of only fledged and depredated nests suggests that higher tides influenced nest survival by increasing nest predation, substantially so for marsh wrens. Other factors negatively associated with marsh wren nest survival, albeit less strongly, included precipitation and the amount of black needlerush at and within 50 m of the nest. The effect of tide height on nest survival suggests that salt marsh birds in northeast Florida are vulnerable to continued sea-level rise, which is exacerbated by upland development that will hinder marsh migration. Monitoring and protecting northeast Florida’s high-elevation, cordgrass-dominated marshes should be a priority.

中文翻译：

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潮汐和栖息地特征影响佛罗里达州东北部盐沼鸣禽的生存

潮汐盐沼面临着威胁其生态完整性的众多压力，许多盐沼脊椎动物的数量随着盐沼栖息地的退化而减少。我们研究了 MacGillivray 的海滨麻雀 Ammospiza maritima macgillivraii 和 Worthington 的沼泽鹪鹩 Cistothorus palustris griseus 在光滑的草甸 Spartina alterniflora 和黑色针叶草 Juncus roemerianus 中的巢存活率，了解为什么在 2015 年至 2015 年期间，这两种物种在美国佛罗里达州东北部的盐沼中占主导地位. 我们评估了潮汐、栖息地特征和天气对巢穴生存的影响。两个物种的巢从产蛋到雏鸟存活的概率都很低（海边麻雀：0.03，95% CI：0.00，0.10；沼泽鹪鹩：0.10，95% CI：0.04，0.18），表明巢穴存活可能会限制人口增长。对沼泽鹪鹩和海边麻雀巢生存的最大威胁来自高于正常的高潮。然而，由于洪水导致巢穴直接损失的证据有限。仅对成熟和退化的巢穴进行的分析表明，较高的潮汐通过增加巢穴捕食来影响巢穴的生存，对于沼泽鹪鹩来说也是如此。其他与沼泽鹪鹩的巢生存负相关的因素包括降水和巢内 50 m 内的黑色针刺数量，尽管强度较小。潮汐高度对巢穴生存的影响表明，佛罗里达州东北部的盐沼鸟类容易受到海平面持续上升的影响，而高地开发会阻碍沼泽迁徙，从而加剧了海平面上升。