Relative Fitness and Behavioral Compensation of Amphibians in a Managed Forest

Habitat loss and degradation are two of the most important factors leading to the imperilment of species worldwide including amphibians, but mechanisms underlying these changes are poorly understood. To understand the fitness potential of harvested forests, I conducted studies of a forest specialist, Rana sylvatica (Wood Frogs) and compared these results with those from identical studies with an open canopy specialist, R. pipiens (Northern Leopard Frogs) in response to an unharvested control and three forest harvesting treatments: clearcutting (with removal of all merchantable timber \u3e 10 cm diameter), clearcutting with coarse woody debris retention, and partial harvesting with removal of \u3c 25% canopy cover. First, I used radio-telemetry data collected on 72 adult R. sylvatica and 40 R. pipiens and logistic regression modeling to assess habitat selection Second, I predicted and quantified the plasticity of the two frogs with respect to survival, time to metamorphosis, and growth rate. My results suggest that R. pipiens may use clearcut areas during the spring and summer that are within migration distance of breeding and overwintering habitats if dense ground vegetation has regenerated. However, the fitness potential of the clearcut treatments for R. sylvatica is lower than that of the forested treatments, and coarse woody debris retention may ameliorate some of the effects of clearcut harvesting. Further, partial harvesting with removal of \u3c 25% canopy cover is a forest management technique that may not adversely influence the fitness of R. sylvatica. Larval R. sylvatica from open-canopy treatments reached a minimum size and metamorphosed earlier than other treatments, but ultimately, juveniles attained the same mass in all four treatments; open-canopy treatments, however, had 35 ± 2% fewer survivors than forested treatments. In contrast, survival of R. pipiens larvae increased with decreasing canopy cover, increasing water temperature, and increasing food availability, and juveniles remained larger and had higher survival in open-canopy treatments. In summary, the treatments induced opposing changes in the fitness correlates at the aquatic and terrestrial life stages of R. sylvatica but not R. pipiens. Further, each species selected different harvest treatments, and havesting affected the habitat selection of both species at multiple scales

A multi-scale assessment of amphibian habitat selection: Wood frog response to timber harvesting

To understand changes in habitat selection in response to timber harvesting, we used radio-telemetry data from 82 adult wood frogs (Lithobates sylvaticus, formerly Rana sylvatica) and logistic regression modelling to assess habitat selection in response to an unharvested control and 3 forest management techniques: clearcutting (with removal of all merchantable timber \u3e 10 cm diameter), clearcutting with coarse woody debris (CWD) retention, and partial harvesting with retention of ∼50% canopy cover. At the home range scale, frogs selected the partially harvested treatment in spring 2005 and avoided the CWD-retained treatment in fall 2006. Frogs spent 5 ± 2 d (mean ± SE) longer in forested treatments than in both clearcut treatments, but certain individuals were able to specialize on the clearcut treatments. At the weekly activity centre scale, the best-supported models indicated that frogs were more likely to occupy locations with more complex ground structure, especially coarse woody debris, warmer temperatures, moister substrates, and greater canopy cover than random. Resource use among frogs overlapped substantially at both the weekly activity centre and daily microhabitat scales. Frogs selected daily microhabitats with more complex ground structure, greater canopy cover, and moister substrates than random. Selection at coarser scales may be mechanistically linked to finer scale resource selection by the physiological processes of thermoand hydro-regulation. Our results support recommendations for minimizing the impact of logging by retaining coarse woody debris in clearcuts and partial harvesting with retention of ∼50% canopy cover

Amphibian Biomass Export from Geographically Isolated Wetlands: Temporal Variability, Species Composition, and Potential Implications for Terrestrial Ecosystems

Recently metamorphosed amphibians transport substantial biomass and nutrients from wetlands to terrestrial ecosystems. Previous estimates (except 1) were limited to either a subset of the community or a single year. Our goal was to examine temporal variability in biomass export of all amphibians within breeding ponds and the composition of that export. We completely encircled ponds with drift fences to capture, count, and weigh emerging recently metamorphosed individuals in Maine (four wetlands, six years) and Missouri (eight wetlands, 2–4 years). We estimated total amphibian biomass export, export scaled by pond surface area, species diversity, and percentage of biomass from anurans. Biomass export and export composition varied greatly among ponds and years. Our estimates were of similar magnitude to previous studies. Amphibian biomass export was higher when species diversity was low and the proportion of anurans was higher. Biomass estimates tended to be highest for juvenile cohorts dominated by a single ranid species: green frogs (Missouri) or wood frogs (Maine). Ranid frogs made up a substantial proportion of amphibian biomass export, suggesting that terrestrial impacts will likely occur in the leaf litter of forests. Future studies should examine the impacts of ranid juveniles on terrestrial ecosystem dynamics

Phylogenomic analysis of a 55.1 kb 19-gene dataset resolves a monophyletic Fusarium that includes the Fusarium solani species complex

International audienceScientific communication is facilitated by a data-driven, scientifically sound taxonomy that considers the end-user's needs and established successful practice. Previously (Geiser et al. 2013; Phytopathology 103:400-408. 2013), the Fusarium community voiced near unanimous support for a concept of Fusarium that represented a clade comprising all agriculturally and clinically important Fusarium species, including the F. solani Species Complex (FSSC). Subsequently, this concept was challenged by one research group (Lombard et al. 2015 Studies in Mycology 80: 189-245) who proposed dividing Fusarium into seven genera, including the FSSC as the genus Neocosmospora, with subsequent justification based on claims that the Geiser et al. (2013) concept of Fusarium is polyphyletic (Sandoval-Denis et al. 2018; Persoonia 41:109-129). Here we test this claim, and provide a phylogeny based on exonic nucleotide sequences of 19 orthologous protein-coding genes that strongly support the monophyly of Fusarium including the FSSC. We reassert the practical and scientific argument in support of a Fusarium that includes the FSSC and several other basal lineages, consistent with the longstanding use of this name among plant pathologists, medical mycologists, quarantine officials, regulatory agencies, students and researchers with a stake in its taxonomy. In recognition of this monophyly, 40 species recently described as Neocosmospora were recombined in Fusarium, and nine others were renamed Fusarium. Here the global Fusarium community voices strong support for the inclusion of the FSSC in Fusarium, as it remains the best scientific, nomenclatural and practical taxonomic option available