Dataset Information

Introduced beaver improve growth of non-native trout in Tierra del Fuego, South America.

ABSTRACT: Species introductions threaten ecosystem function worldwide, and interactions among introduced species may amplify their impacts. Effects of multiple invasions are still poorly studied, and often, the mechanisms underlying potential interactions among invaders are unknown. Despite being a remote and well-conserved area, the southern portion of South America has been greatly impacted by invasions of both the American beaver (Castor canadensis) and Brown Trout (Salmo trutta fario). Here, we compared growth, condition, diet, and stable isotopes of sulfur ?34S, nitrogen ?15N, and carbon ?13C for stream-living Brown Trout from streams with (n = 6) and without (n = 6) beaver in Tierra del Fuego, Chile. We show that beaver may facilitate the success of trout by positively influencing fish growth. Beaver indirectly provide greater food subsidies (i.e., macroinvertebrate abundances) by modifying the local aquatic environment through active dam and lodge building suggesting a one-way positive interaction. Trout in beaver-influenced streams occupied a slightly higher trophic level with more depleted sulfur and carbon isotopic ratios suggesting that food web pathways rely on secondary production from autochthonous origin. Trout in beaver-influenced streams had a wider dietary breadth with diptera and amphipoda as the prey items providing most of the energy, whereas in streams without beaver, trichoptera were the main source of energy for trout. Ultimately, we find that these two species, which have never co-occurred naturally, bring about the same ecosystem function and the beneficial influences in their native ranges as in invaded systems.

SUBMITTER: Arismendi I

PROVIDER: S-EPMC7487219 | biostudies-literature | 2020 Sep

REPOSITORIES: biostudies-literature

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Introduced beaver improve growth of non-native trout in Tierra del Fuego, South America.

Arismendi Ivan I Penaluna Brooke E BE Jara Carlos G CG

Ecology and evolution 20200817 17

Species introductions threaten ecosystem function worldwide, and interactions among introduced species may amplify their impacts. Effects of multiple invasions are still poorly studied, and often, the mechanisms underlying potential interactions among invaders are unknown. Despite being a remote and well-conserved area, the southern portion of South America has been greatly impacted by invasions of both the American beaver (<i>Castor canadensis</i>) and Brown Trout (<i>Salmo trutta fario</i>). H ...[more]

PMID: 32953074

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Project description:Quantifying the presence and environmental impact of invasive species is the starting point for research on management and nature conservation. North American beavers (Castor canadensis) were introduced to Argentina from Canada in 1946, and the species has been identified as a major agent of environmental change in the Tierra del Fuego archipelago in the Anthropocene. We studied the invasion status (distribution and density) of beavers through analyses of the dam densities in the Tierra del Fuego landscapes. We identified beaver dams with a GIS using visual interpretation of high-resolution aerial imagery from Microsoft Bing, Google Earth and HERE and related them to natural environmental gradients. These factors comprised geographic (vegetation zones and distance to streams), climatic (temperature, precipitation, evapotranspiration and net primary productivity) and topographic (elevation and slope) data. The datasets (dams and factors) were combined, and the data from the different zonation classes were subsequently compared using ANOVAs and Tukey's mean comparison tests. Deviations from the mean density (x mean density-x total mean density) were calculated to visualize the deviations for the studied factors. The datasets were also evaluated using principal component analyses (PCA). Our results showed a total of 206,203 beaver dams (100,951 in Argentina and 105,252 in Chile) in the study area (73,000 km2). The main island of Tierra del Fuego presented a greater degree of invasion (73.6% of the total study area) than the rest of the archipelago, especially in areas covered by mixed-evergreen and deciduous forests. The studied geographic, climatic and topographic factors showed positive trends (higher beaver preference) with beaver spread, which were all significant (p <0.05) when compared across the landscape. Although beavers are flexible in their habitat use, our empirical records showed that they had marked preferences and were positively influenced by the most productive forests. Here, we describe a scientific panorama that identified the drivers of species invasion based on satellite data and the available ecological datasets. The identification of such drivers could be useful for developing new tools for management and/or control strategies of the beavers in the Tierra del Fuego archipelago.

Dataset Information

Introduced beaver improve growth of non-native trout in Tierra del Fuego, South America.

Publications

Introduced beaver improve growth of non-native trout in Tierra del Fuego, South America.

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