臺北市蛙類的空間分布與長期趨勢

Abstract

都市的開發造成環境地貌快速地改變，棲地流失造成生物群聚的改變，對生物多樣性造成巨大的威脅，對蛙類而言影響更為明顯。蛙類是生態系統中重要的指標物種，牠們對於環境變化非常敏感，時常被當作長期監測的對象。不同蛙類的習性差異大，對環境耐受程度也不同，導致部分種類快速消失，但也有些種類能適應都會環境。為瞭解蛙類在都會環境下的分布及長期趨勢，本研究運用臺北市生物多樣性指標調查資料，分析2009 – 2021年間於35個樣點的蛙類調查資料，計算種豐度、量豐度、辛普森多樣性指數、香儂多樣性指數、均勻度，及相對豐度幾何平均值，探討臺北市蛙類群集的變化。運用iNext.4steps計算種豐度、優勢種與豐富種。研究結果顯示，在臺北市的山區環境有較高的多樣性，都會公園、河濱與農墾地較低；水域環境會是影響公園環境蛙類組成的重要因素。種豐度易受到稀有種的影響略減，量豐度則先上升再下降，多樣性與均勻度指數平緩地上升，整體的趨勢變異不大，顯示優勢物種的數量逐漸減少，使得多樣性指數增加，均勻度趨於均衡。各類群的變化趨勢略有不同，溪流水域型的蛙類的趨勢減少，樹棲型蛙類的趨勢增加，池塘水域型蛙類的年間變異增加。本研究建議運用不同生物多樣性指標，探討不同區域間優勢種與稀少種的變化趨勢；並利用不同型態的指標物種，來反應不同環境的生物多樣性變化趨勢。

The rapid development of urban areas has led to significant changes in environmental landscapes, resulting in habitat loss and alterations in biological communities, posing a major threat to biodiversity. The impact is particularly evident for amphibians. Frogs are important indicator species in ecosystems, as they are highly sensitive to environmental changes and are often used for long-term monitoring. Different frog species exhibit varying behaviors and tolerances to environmental conditions, causing some species to disappear rapidly while others adapt to urban environments. To understand the distribution and long-term trends of frogs in urban environments, this study utilizes data from Taipei City's Biodiversity Index Survey, analyzing frog survey records from 35 sampling sites between 2009 and 2021. The study calculates species richness, abundance, Simpson’s diversity index, Shannon diversity index, evenness, and the geometric mean of relative abundance to examine changes in frog assemblages in Taipei City. The iNext.4steps method is used to calculate species richness, dominant species, and abundant species. The results indicate that mountain areas in Taipei exhibit higher biodiversity, while urban parks, riversides, and agricultural lands show lower diversity. Aquatic environments significantly influence the composition of frog communities in park areas. Species richness slightly decreases due to the influence of rare species, while abundance initially increases before declining. Diversity and evenness indices show a gradual upward trend with minimal overall variation, suggesting that the number of dominant species is decreasing, leading to an increase in diversity and a more balanced evenness. Different frog groups exhibit distinct trends: stream-dwelling species show a declining trend, arboreal species display an increasing trend, and pond-dwelling species exhibit greater annual variation. This study suggests using various biodiversity indices to analyze trends in dominant and rare species across different areas. Additionally, employing different types of indicator species can help reflect biodiversity changes in various environmental conditions.