Population Survey Data for Coastal Giant Salamanders in the Chilliwack River Valley

The Coastal Giant Salamander (Dicamptodon tenebrosus, formerly known as Pacific giant salamander) is considered a species at risk (Assessed as Threatened by COSEWIC and red-listed by BC-CDC), and the primary putative threat in BC is forestry. Forestry operations impact both the aquatic and terrestrial habitats of the salamanders. Lack of forest cover exposes the adults to wider temperature extremes and the possibility of desiccation. Development of land for farming and settlement along Vedder Mountain and the Cultus Lake area has encroached on the B.C. distribution range of Dicamptodon tenebrosus. Adults depend on riparian forests, which are often removed by logging. In the streams, larvae (and neotenic adults) must cope with more variable stream flows, erosion and sedimentation of stream habitats, and increased water temperatures. This long-term (1994-2001) mark-recapture study of Coastal Giant Salamanders led by Dr. John Richardson (UBC) and Dr. William Neill (UBC) took place in 12 small streams in the Chilliwack River Valley, BC. This study includes survey data to assess whether forest harvest history near the streams or other geomorphic characteristics impacted density, survival, and growth rates. These data, the only long-term data using mark-recapture designs (CJS, using Lebreton design) for this species anywhere, will play a crucial role in future recovery efforts for this threatened species in Canada. The scientific value is high in understanding population dynamics and in the face of continued land use impacts and climate change, offering hope for the future of these salamanders.沿海巨螈（Coastal Giant Salamander，学名Dicamptodon tenebrosus，曾被称为太平洋巨螈）被列为受风险物种：加拿大濒危野生动物状况委员会（Committee on the Status of Endangered Wildlife in Canada, COSEWIC）将其评定为受威胁物种，且不列颠哥伦比亚省保护数据中心（BC-CDC）将其列入红色名录。在不列颠哥伦比亚省（BC），该物种面临的主要推测性威胁为林业活动。林业作业会同时破坏该蝾螈的水生与陆生栖息地。森林覆盖的缺失会使成体暴露于更剧烈的温度波动中，并增加其脱水的可能性。韦德山（Vedder Mountain）与卡尔特斯湖（Cultus Lake）区域的农业开发与定居用地扩张，已侵占了不列颠哥伦比亚省内Dicamptodon tenebrosus的分布范围。成体依赖河岸森林，而这类林带常因伐木活动被清除。在溪流生境中，幼体（以及幼态成熟的成体）需应对更不稳定的溪流流量、溪流生境的侵蚀与沉积，以及水温升高的压力。这项由不列颠哥伦比亚大学（University of British Columbia, UBC）的约翰·理查森博士（Dr. John Richardson）与威廉·尼尔博士（Dr. William Neill）主导的长期（1994-2001年）沿海巨螈标记重捕研究，在不列颠哥伦比亚省奇利瓦克河谷（Chilliwack River Valley）的12条小型溪流中开展。本研究包含调查数据，旨在评估溪流周边的森林采伐历史或其他地貌特征是否会对种群密度、存活率与生长速率造成影响。这些数据是全球范围内首个采用标记重捕实验设计（Cormack-Jolly-Seber模型，即CJS，采用勒布雷顿（Lebreton）框架）的该物种长期数据集，将在加拿大境内这一受威胁物种的后续恢复工作中发挥关键作用。在持续的土地利用影响与气候变化的背景下，该数据集对于理解种群动态具有极高的科学价值，为这类蝾螈的未来存续带来了希望。