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Here, we examine the effects of adjacent land use in a managed forest on pond-breeding amphibian species richness and community composition at 34 New Brunswick, Canada, ponds. Amphibian species richness was negatively correlated with the proportion of roads, precommercial thinning, and hardwood forest and positively correlated with the proportion of wetlands in adjacent lands. These land-use effects peak at 180 m from the ponds. Road density was negatively correlated with Lithobates catesbeiana and Lithobates septentrionalis presence. Precommercial thinning was negatively correlated with Ambystoma spp. presence and positively correlated with Anaxyrus americanus presence. Wetlands were positively correlated with L. septentrionalis and Notopthalamus viridescens presence. Correlations were also found between water table height and A. americanus, Lithobates palustris, and Ambystoma spp. presence. In addition, L. catesbeiana and N. viridescens presence-absence was positively correlated with the proportion of mature and overmature forest on the landscape (at scales of 500 and 1000 m, respectively). Lastly, the proportion of regenerating and sapling forest on the landscape was negatively correlated with L. palustris presence-absence but, by contrast, was positively correlated with A. americanus. These results suggest that the effects of adjacent land use may significantly impact amphibian populations in managed eastern Canadian forests. Nous avons examine, en regard de l'utilisation du territoire adjacent, la richesse specifique et la composition des communautes d'amphibiens de 34 etangs situes en foret amenagee au Nouveau-Brunswick, au Canada. La richesse specifique en amphibiens etait negativement correlee a la proportion de chemins, de peuplements traites par eclaircie precommer-ciale et de foret feuillue et positivement correlee a la proportion de milieux humides dans les territoires adjacents. Ces effets du contexte paysagers culminaient a 180 m des etangs. La densite des chemins etait negativement correlee a la presence de Lithobates catesbeiana et Lithobates septentrionalis. L'eclaircie precommerciale etait negativement correlee a la presence d'Ambystoma spp. et positivement correlee a la presence d'Anaxyrus americanus. Les milieux humides etaient positivement correles a la presence de L. septentrionalis et Notopthalamus viridescens. Des correlations ont aussi ete trouvees entre la hauteur de la nappe phreatique et la presence d'A. americanus, Lithobates palustris et Ambystoma spp. De plus, la presence-absence de L. catesbeiana et N. viridescens etait positivement correlee a la proportion de foret mature et surannee dans le paysage (aux echelles respectives de 500 et 1000 m). Finalement, la proportion de foret en regeneration et au stade gaulis dans le paysage etait negativement correlee a la presence-absence de L. palustris mais, a l'inverse, l'etait positivement avec A. americanus. Ces resultats indiquent que l'utilisation du territoire adjacent peut avoir des effets significatifs sur les populations d'amphibiens dans les forets amenagees de l'est du Canada. [Traduit par la Redaction], Introduction Forestry practices alter natural landscapes and may negatively affect wildlife populations and communities, especially if forests are not properly managed (Freedman et al. 1994; Noss 1999). In particular, amphibian [...]

Author(s): Jeff. E. Houlahan (corresponding author) [1]; C. Scott Findlay [1, 2]; Benedikt R. Schmidt [3]; Andrea H. Meyer [4]; Sergius L. Kuzmin Although there is growing concern that amphibian [...]

Kejimkujik National Park and National Historic Site, Nova Scotia, Canada, is considered a biological mercury (Hg) hotspot because the tissues of yellow perch ( Perca flavescens) and common loons ( Gavia immer) inhabiting the lakes frequently exceed so-called safe levels of Hg. In the present study, the relationships between Hg and overall health of males and females of 3 forage fish species (brown bullhead Ameirus nebulosus, banded killifish Fundulus diaphanus, and golden shiner Notemigonus crysoleucas; n = 6-18/sex/lake) in 6 lakes at the park were assessed using condition factor, liversomatic index (LSI), and macrophage aggregates (MAs; indicators of tissue damage). Mean muscle total Hg (THg) concentrations of brown bullhead, banded killifish, and golden shiner across lakes were 0.32 μg/g, 0.27 μg/g, and 0.34 μg/g, respectively. Condition was negatively related to muscle THg in golden shiner and banded killifish, LSI was not related to THg in any species, and all species showed evidence of increasing MA prevalence (counts and area) with increasing THg concentrations. The MAs were most prevalent in spleen tissues of golden shiner, with mean percentage cover ranging from 0.36% to 5.59% across lakes. In addition, the area of MAs appeared to be better predicted by THg concentration than was the number of MAs in the same tissue. These findings suggest that Hg is affecting the health of wild fishes in Kejimkujik National Park and National Historic Site and that other populations with similar or higher concentrations of this metal may also be at risk. Environ Toxicol Chem 2017;36:976-987. © 2016 SETAC [ABSTRACT FROM AUTHOR]

Analyzes a study which examined the means of trends for global amphibian population declines during the 1950s and 1960s. Application of the least-squares mean to estimate the annual mean global decline in amphibian population; Factors that contributed to amphibian population declines.