Centro de Investigación Esquel de Montaña y Estepa Patagónica (CONICET-UNPSJB), Roca 780, Esquel, Chubut, Argentina; Facultad de Ciencias Naturales y Ciencias de la Salud, Universidad Nacional de la Patagonia San Juan Bosco, Esquel, Chubut, Argentina.
U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, 3200 SW Jefferson Way, Corvallis, OR 97331, United States of America.
Sci Total Environ. 2021 Jan 15;752:141864. doi: 10.1016/j.scitotenv.2020.141864. Epub 2020 Aug 21.
The effects of volcanic disturbance on aquatic communities and their recovery are poorly studied. To fill this gap, we explored the effects on fish communities in rivers in Argentina of the 2008 eruption of Chaitén Volcano in southern Chile (42.8° lat. S). The eruption produced volcanic plumes of ash that persisted in the atmosphere for several months. Borne on westerly winds, deposits of tephra crossed the Andes Mountains, reaching the Atlantic coast (Argentina). We compared the pre- and post-eruption abundances of a native catfish Hatcheria macraei, and two introduced trout from rivers covered by the volcanic plumes (Argentina) using Before-After-Control-Impact analysis to explore fish recovery. Total suspended solids from volcanic ashfall, macroinvertebrate abundance and richness, and species ecological attributes influenced the spatial arrangement of fish in rivers. Twenty-one months after the eruption, Rainbow Trout, Oncorhynchus mykiss, had not returned to pre-eruption abundances in the sampled rivers, and only four rivers had regained pre-eruption species composition, suggesting that disturbance is still ongoing. The abundance of introduced fishes was strongly, negatively correlated with TSS, suggesting that ashfall affected these fish probably by clogging and abrasion of the gills. Fish recolonized previously occupied habitats 4 days to 9 months after the disturbance. Hatcheria macraei was the slowest to recolonize, whereas O. mykiss were the pioneer fish in 4 rivers following the eruption and recolonized all 5 rivers where they were present prior to the eruption. In one river, the catfish and the Brown Trout, Salmo trutta, were still absent 21 months post-eruption, potentially owing to the lack of riparian cover that would have deflected the entry of ash. Rainbow Trout suffered significant declines in abundance, whereas Brown Trout and catfish generally did not, owing to their ecological attributes. Total fish abundance was negatively correlated with ash thickness, but positively related to prey availability.
火山干扰对水生群落及其恢复的影响研究甚少。为了填补这一空白，我们探讨了 2008 年智利南部柴滕火山喷发（南纬 42.8°）对阿根廷河流中鱼类群落的影响。这次喷发产生了持续数月的火山灰羽流。在西风的作用下，火山灰沉积物穿过安第斯山脉，到达大西洋海岸（阿根廷）。我们使用“事前-事后-对照-影响（Before-After-Control-Impact）”分析方法，比较了受火山灰羽流影响的河流中本地鲶鱼 Hatcheria macraei 和两种外来虹鳟 Oncorhynchus mykiss 和溪红点鲑 Salvelinus fontinalis 的丰度，以探讨鱼类的恢复情况。火山灰沉降的总悬浮固体、大型无脊椎动物的丰度和丰富度以及物种的生态特征影响了鱼类在河流中的空间分布。喷发后 21 个月，虹鳟鱼尚未恢复到采样河流的喷发前丰度，只有四条河流恢复了喷发前的物种组成，这表明干扰仍在继续。引入鱼类的丰度与 TSS 呈强烈负相关，表明灰沉降可能通过堵塞和磨损鳃而影响这些鱼类。鱼类在干扰后 4 天到 9 个月重新占领了先前占据的栖息地。Hatcheria macraei 是恢复最慢的鱼类，而 O. mykiss 是喷发后四条河流中的先锋鱼类，并重新占领了它们在喷发前存在的所有 5 条河流。在一条河流中，鲶鱼和褐鳟仍然在喷发后 21 个月缺失，可能是由于缺乏会偏转灰沉降的河岸植被。虹鳟鱼的丰度显著下降，而褐鳟和鲶鱼则没有，这是由于它们的生态特征。鱼类总丰度与灰沉降厚度呈负相关，但与猎物供应呈正相关。
