SM4：聲學區域工作流程，用于有效比較不同入侵哺乳動物管理制度下的聲域
Abstract
One quarter of all terrestrial native bird species have become extinct since human arrival in New Zealand, leading to a pervasive silence in many natural environments due to the decrease in native bird song. Passive acoustic techniques are a potential tool for environmental monitoring, especially for testing whether the control of mammals can reverse the ‘silent forest’ effect. Here we compare soundscapes from two nearby sites within the Waitakere Ranges Regional Park, New Zealand, that have contrasting predator control levels: one with high-level pest mammal control, and the other with low-level pest control. Measurements of twelve acoustic indices extracted from two seasons of passive acoustic recordings are split into 20 acoustic regions to identify which regions best discriminate between the two management regimes. We define the acoustic regions as units of analysis bounded by a specific time period and frequency range chosen to capture the main groups of biologically relevant acoustic events within a soundscape. Analysis of variance and pairwise comparisons indicated the acoustic region bounded from 9 pm to 11:59 pm and a range of 0.988–3.609 kHz in autumn presented the greatest differences between sites. The sounds responsible for these acoustic differences were generated by invasive mammals in the site with no pest control. Results also supports spring season as the most important for bird monitoring in New Zealand. Acoustic indices analysis did not detect a reversal of the ‘silence forest’ effect in the site with high-level predator control.
摘要：
自人類抵達新西蘭以來，四分之一的陸地本土鳥類已經滅絕，由于本土鳥類歌聲的減少，許多自然環境中普遍沉默。被動聲學技術是一種潛在的環境監測工具，特別是用于測試對哺乳動物的控制是否可以扭轉“寂靜森林”效應。在這里，我們比較了新西蘭懷塔克雷山脈區域公園內兩個附近地點的音景，這兩個地點的捕食者控制水平存在差異：一個是高級害蟲哺乳動物控制，另一個是低級害蟲控制。從兩個季節的被動聲學記錄中提取的12個聲學指標的測量值被分為20個聲學區域，以確定哪些區域最能區分兩種管理制度。我們將聲學區域定義為以特定時間段和頻率范圍為界的分析單元，這些時間段和范圍被選擇用于捕捉聲景中主要的生物相關聲學事件。方差分析和成對比較表明，秋季從晚上9點到晚上11點59分的聲學區域和0.988-3.609 kHz的范圍在不同地點之間存在最大差異。造成這些聲學差異的聲音是由該地區沒有害蟲控制的入侵哺乳動物產生的。研究結果還支持春季是新西蘭鳥類監測最重要的季節。聲學指標分析沒有檢測到在捕食者控制水平較高的地點“寂靜森林”效應的逆轉。
關鍵詞：SM4 聲學記錄儀，Wildlife野外聲學監測，鳥鳴聲監測，野生動物聲學記錄，Wildlife Acoustics 野生動物聲學
