連結棲地品質與珊瑚礁魚類群聚跨生活史組成

Abstract

珊瑚礁魚類群聚正面臨漁業活動、沿海開發與氣候變遷等重大威脅,導致棲地大規模喪失與如添入(recruitment)等關鍵生態過程的中斷。理解環境因子對魚類群聚的影響需進一步掌握棲地劣化的機制,而這也是當前研究中的知識缺口。本博士研究結合生物、地形與聲學指標,評估棲地品質對珊瑚礁魚類群聚不同生活史階段的影響。首先,我探討活珊瑚與死亡珊瑚如何影響不同生活史階段的魚類群聚。其次,我分析結構複雜度、底棲組成與珊瑚礁聲景在兩座島嶼上如何影響魚類添入。最後,我整合幼魚與成魚豐度、底棲覆蓋率與人為噪音,評估台灣第一座海洋保護區(Marine Protected Area, MPA)的棲地品質。小尺度實驗(第二章)顯示,死亡的分枝狀珊瑚可為行動性高的魚類幼苗提供暫時性庇護;相對地,成魚則更依賴具有能量供應、結構穩定性與支持關鍵生態功能的活分枝狀珊瑚。島嶼尺度調查(第三章)發現,魚類添入隨結構複雜度增加而上升,且在以絲狀藻類或軟珊瑚為主的礁體中顯著下降,凸顯硬珊瑚覆蓋在支持添入上的重要角色。此外,添入魚種的多樣性與夜間魚類合唱頻段的聲音強度呈正相關,顯示特定聲學線索在魚苗定居期間的重要性。棲地品質評估(第四章)依據底棲與魚類群聚指標及人為噪音程度,辨識出「機會區」與「風險區」,其中一處高機會區目前未受保護,並針對兩處風險區提出管理策略。未來研究應整合生態與聲學指標於多因子分析架構中,以更深入了解棲地品質如何形塑珊瑚礁魚類群聚,並支持更有效的保育策略。Coral reef fish assemblages face significant threats from fishing activities, coastal development, and climate change leading to extensive habitat loss and disruptions to key ecological processes, such as recruitment. Understanding the influence of environmental factors on fish communities requires deeper insights into the mechanisms of habitat degradation, a knowledge gap in current research. This Ph.D. study integrates biological, topographic, and acoustic indicators to assess the effects of habitat quality on different life stages of reef fish assemblages. First, I examined how live and dead corals affect fish assemblages across life stages. Second, I investigated the role of topographic complexity, benthic composition, and reef soundscapes in shaping fish recruitment across two islands. Finally, I assessed habitat quality within Taiwan’s first marine protected area (MPA) by integrating juvenile and adult fish abundance, benthic cover, and anthropogenic noise. Small-scale experiments (Chapter 2) revealed that dead branching corals can provide temporary shelter for mobile fish recruits, whereas adults were more dependent on live branching corals that offer energetic input, structural stability, and support key ecological functions. Findings from island-scale surveys (Chapter 3) showed that recruitment increases with rugosity and is significantly reduced on reefs dominated by turf algae or soft corals—highlighting the role of hard coral cover in supporting recruitment. Additionally, recruitment richness was positively associated with nighttime sound levels at frequencies characteristic of fish choruses, suggesting the importance of specific acoustic cues during settlement. Habitat quality assessments (Chapter 4) identified “opportunity” and “risk” zones based on benthic and fish assemblage data and levels of anthropogenic noise, revealing a currently unprotected high-opportunity area and proposing management strategies for two high-risk sites. Future research should integrate ecological and acoustic indicators into multifactorial frameworks to better understand how habitat quality shapes reef fish assemblages and to support more effective conservation strategies.