The effect of fish and aquatic habitat complexity on amphibians

Abstract

Fish introductions are considered one of the most widespread anthropogenic threats to aquatic ecosystems. Their negative impact on native amphibian communities has received increasing attention in recent years. We investigated the relationship between the introduced fish, emergent vegetation cover and native amphibians in man-made ponds generated by regulation and dam building along the Tâ rnava Mare Valley (Romania) during the last 40 years. We inventoried amphibians and fish inhabiting 85 permanent ponds and estimated habitat complexity focusing on emergent vegetation cover. Four amphibian species were found to be negatively associated with the presence of predatory fish. Species richness of ponds without fish and ponds without predatory fish did not differ significantly, whereas ponds containing only predatory fish had significantly lower amphibian richness. A significant positive relationship was found between the emergent vegetation cover and pond occupancy of six amphibian species and amphibian species richness. As a management recommendation, we suggest the restriction of fish introductions to non predatory fish and the maintenance of high emergent vegetation cover in the ponds.

Can the introduction of Xenopus laevis affect native amphibian populations? Reduction of reproductive occurrence in presence of the invasive species

“…However, the occurrence of reproduction and the relative abundance of tadpoles of the common toad was not affected by presence of the African clawed frogs. The common toad is resistant against some other alien species including predatory fish (Cruz et al 2006;Hartel et al 2007;Orizaola and Braña 2006). Moreover, the reproductive activity of the common toad in the study area occurs during the coldest months (December/February), when the activity of African clawed frogs is low due to low temperatures (Casterlin and Reynolds 1980;Measey 2001).…”

Pond‐based survey of amphibians in a Saxon cultural landscape from Transylvania (Romania)

“…The area studied by us allows proper conditions for these species and a large species richness since the permanent ponds are well represented and well vegetated [the mean amount of macrophyte vegetation cover of the ponds being up to 30% ], the ponds without predatory fish are still in high number [41% (Hartel et al 2007a)], the permanent ponds are closely situated to the forests [average distance is 232 m ], the forest coverage is large (Table I), and the land use is, in large part, traditional (Mountford & Akeroyd 2005). In this generally less-fragmented area, the dispersion of juveniles and a quick colonization of the newly created ponds is still possible.…”

“…However, the relatively low values of the AUC for H. arborea and R. dalmatina in the pond occupancy-altitude relationship suggest that other variables have more influential effect than the pond altitude alone. Such variables are, for example, the reed cover of the ponds and the presence of predatory fish (Hartel et al 2007a), but in the case of H. arborea it may also be the light conditions (and implicit the temperature) of the ponds (Pellet & Hoehn 2004). The lack of pond occupancy-altitude relationship for other amphibian species that prefer permanent ponds such as T. cristatus (Gustafson et al 2006;Skei et al 2006) and B. bufo (Scribner ) may be explained by the larger ecological plasticity of these species in the altitudinal range and environmental conditions of this area.…”

“…Despite this, the expected land-use changes, as a result of agricultural development caused by the implementation of the Common Agricultural Policy and infrastructural expansion, represent major potential threats and make the habitat-based inventories even more important as baseline for detecting trends in future monitoring programmes. Previous studies on habitat availability and use by amphibians in this area focused on the characterization of the habitats ), on the relationship between the pond use of individual species and the pond-and landscape features (Hartel et al 2005(Hartel et al , 2007a(Hartel et al , 2008, on the habitat use dynamic of temporary pondbreeding communities (Hartel et al 2005) and on long-term studies of amphibian populations (Hartel 2004).…”

The importance of phenotypic diversity in conservation: Resilience of palmate newt morphotypes after fish removal in Larzac ponds (France)

“…In Larzac, we mainly found goldfish to be present in ponds, but also pumpkinseed to a lesser extent (Supplementary Table 1; Denoël et al 2005a), whereas single cases of other species introductions have also been reported (Rondeau et al 2000). Pumpkinseeds are ferocious predators that can affect all aquatic life stages of amphibians (Parris et al 2001;Hartel et al 2007;Tomeček et al 2007;Bruslé and Quignard 2013). These fish are often present at high densities, forage in the varied aquatic microhabitats, and are also aggressive towards large amphibians such as frogs (Almeida et al 2014).…”