Experimental confirmation of effects of leaf litter type and light on tadpole performance for two priority amphibians

Impact of soil from monoculture pine plantations on two anuran species from the Atlantic Forest: Odontophrynus reigi and Leptodactylus luctator

Monoculture tree plantations reduces landscape heterogeneity and the number and diversity of habitats available for species. Physical-chemical changes in soil may affect the ponds where tadpoles develop. This work aimed to study the effect on tadpoles of two species of frogs, Leptodactylus luctator (Ll) and Odontophrynus reigi (Or) exposed to soils from a pine plantation (PP), which were compared to tadpoles exposed to soils from Atlantic Forest, the native forest (NF). The impact of soils from both places on growth, development, antioxidant system and genetic damage of Ll and Or tadpoles were observed. A composite sample (5 kg) of soil was taken from the top 10 cm stratum in a 200 m transect in each site, with random plots of 50x50cm. In collected soil samples Organic Matter (OM), Organic Carbon (OC), and Total Nitrogen (TN) were determined. We conducted laboratory experiments, from 23 until 38 Gosner stages. During the experiment, pH and ammonium in the water were determined. Soil from NF presented higher content of OM, OC and TN, and water pH in PP was 0.2 units lower than in NF. Both species showed ≈60 % increase of catalase activity in PP, and ≈40 % increase of lipid peroxidation in NF. Ll tadpoles presented 10 times higher protein oxidation in PP than in NF, but Gosner stage was higher in NF. In NF the higher OM and OC in both species causes the increase of lipid peroxidation; and Ll responds to a stressor in PP that in Or is not observed. Or presented lower stress response towards PP soils, which indicates a tolerance towards this soil. The changes observed in soil chemistry, although not big from a physical-chemical point of view, affects the growth, development and oxidative stress of two species of anuran tadpoles from the NF, which can affect future populations and anuran diversity.

Effects of fine-scale habitat quality on activity, dormancy, habitat use, and survival after reproduction in Rana dybowskii (Chordata, Amphibia)

Amphibians are facing population declines and extinctions, and protecting and supplementing refuges can help species survive. However, the microhabitat requirements of most species are unknown, and artificial shelters or burrows have not been well tested for amphibians. Some amphibians exhibit complex behaviour during the transition from post-reproductive dormancy to activity. However, little is known about the ecology, post-reproductive dormancy, and terrestrial activity of amphibians. Here, habitat site selection in experimental enclosures and the effects of shelters (stones, soil) and shade (with and without shade netting) on the activity, exposed body percentage, burrow depth, body-soil contact percentage, and survival of Rana dybowskii were investigated during post-reproductive dormancy and post-dormant activity. The results showed that R. dybowskii live individually under leaves, soil, stones or tree roots. Furthermore, although the dormant sites of frogs are significantly different, the distribution of male and female frogs in these sites is similar. Shading and shelter significantly affected the exposed body percentage, burrow depth and body-soil contact percentage of frogs compared with soil. In the stone group, soil and stone form the frog's refuge/burrow, whereas in the soil group, the refuge/burrow is composed entirely of soil. Even though the soil group has a deeper burrow and a larger area of soil contact with the body, it still has a higher exposure rate than the stone group. Frog activity frequency was affected by shelter and shade; the interaction of shelter and time and the interaction of shading and time were significant. The soil group had a higher activity frequency than the stone group, and the no-shade group had a higher activity frequency than the shade group. Shelter and shading differences do not significantly affect frog survival; however, the death rate during post-reproductive dormancy is lower than that during the active period.

How plants affect amphibian populations

Descriptions of amphibian habitat, both aquatic and terrestrial, often include plants as characteristics but seldom is it understood whether and how those plants affect amphibian ecology. Understanding how plants affect amphibian populations is needed to develop strategies to combat declines of some amphibian populations. Using a systematic approach, we reviewed and synthesized available literature on the effects of plants on pond-breeding amphibians during the aquatic and terrestrial stages of their life cycle. Our review highlights that plant communities can strongly influence the distribution, abundance, and performance of amphibians in multiple direct and indirect ways. We found three broad themes of plants' influence on amphibians: plants can affect amphibians through effects on abiotic conditions including the thermal, hydric, and chemical aspects of an amphibian's environment; plants can have large effects on aquatic life stages through effects on resource quality and abundance; and plants can modify the nature and strength of interspecific interactions between amphibians and other species - notably predators. We synthesized insights gained from the literature to discuss how plant community management fits within efforts to manage amphibian populations and to guide future research efforts. While some topical areas are well researched, we found a general lack of mechanistic and trait-based work which is needed to advance our understanding of the drivers through which plants influence amphibian ecology. Our literature review reveals the substantial role that plants can have on amphibian ecology and the need for integrating plant and amphibian ecology to improve research and management outcomes for amphibians.