Management of amphibian populations to reverse recent declines will require defining high‐quality habitat for individual species or groups of species, followed by efforts to retain or restore these habitats on the landscape. We examined landscape‐level habitat relationships for frogs and toads by measuring associations between relative abundance and species richness based on survey data derived from anuran calls and features of land‐cover maps for Iowa and Wisconsin. The most consistent result across all anuran guilds was a negative association with the presence of urban land. Upland and wetland forests and emergent wetlands tended to be positively associated with anurans. Landscape metrics that represent edges and patch diversity also had generally positive associations, indicating that anurans benefit from a complex of habitats that include wetlands. In Iowa the most significant associations with relative abundance were the length of the edge between wetland and forest ( positive) and the presence of urban land (negative). In Wisconsin the two most significant associations with relative abundance were forest area and agricultural area ( both positive). Anurans had positive associations with agriculture in Wisconsin but not in Iowa. Remnant forest patches in agricultural landscapes may be providing refuges for some anuran species. Differences in anuran associations with deep water and permanent wetlands between the two states suggest opportunities for management action. Large‐scale maps can contribute to predictive models of amphibian habitat use, but water quality and vegetation information collected from individual wetlands will likely be needed to strengthen those predictions. Landscape habitat analyses provide a framework for future experimental and intensive research on specific factors affecting the health of anurans.

This paper demonstrates cooling of the center-of-mass motion of 10 µm-diameter optically levitated silica spheres to an effective temperature of 50 ± 22 µK, achieved by minimizing the technical pointing noise of the trapping laser. This low noise leads to an acceleration and force sensitivity of 95 ± 41 ng/ √ Hz (g = 9.8 m/s 2 ) and 0.95 ± 0.11 aN/ √ Hz, respectively, at frequencies near 50 Hz. This force sensitivity is comparable to that demonstrated for optically levitated nanospheres that are 10 4 times less massive, corresponding to an acceleration sensitivity that is several orders of magnitude better. It is further shown that under these conditions the spheres remain stably trapped at pressures of ∼ 10 −7 mbar with no active cooling for periods longer than a day. Feedback cooling is still necessary in the moderate-pressure regime, motivating a comprehensive study of the loss mechanisms of the microspheres and providing better understanding of the requirements for feedback-free optical trapping in vacuum. This work can enable high-sensitivity searches for accelerations and forces acting on micron-sized masses, including those that could be produced by new physics beyond the Standard Model.

We used data from a statewide frog monitoring network to investigate population turnover and synchrony in eight wetland‐breeding species. We found that subpopulations at many sites turn over frequently, with breeding choruses absent or undetectable in most years. Frequencies of detection across sites were significantly associated with the density of wetland patches (all species) and the areal extent of several terrestrial land cover categories (seven species) within 1 km. Intraspecific population fluctuations were statistically synchronized between survey sites separated by up to 50–100 km, but synchrony was not strong. Anuran abundances were significantly correlated with rainfall 1–4 years earlier, indicating that rainfall influences population fluctuations. However, population synchrony was much weaker than rainfall synchrony. Managers attempting to maintain amphibian populations regionally should focus on maintaining landscapes with high densities of wetlands and sufficient upland habitat resources. The dynamic nature of amphibian populations at individual wetlands is well known, and our results suggest that species distributions at the landscape level are similarly dynamic.

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