Large-scale land abandonment and reconstruction activity has altered the ecosystem structure in the evacuation area for the Fukushima Daiichi power plant accident in 2011. Despite social concerns about changes in the avian assemblages that occurred after the accident, publicly accessible data are quite limited. We engaged in acoustic monitoring of birds using digital voice recorders from 2014 in and around the Fukushima evacuation zone. All monitoring sites were located within schoolyards (including those that had been converted to community centers) to examine the bird assemblages in the urban and rural landscapes that were heavily altered by land abandonment due to the nuclear plant accident. A digital voice recorder was installed at each monitoring site during May-July, and we recorded 20 min a day using timer-recording mode. We divided the audio data into 1-min segments and identified species occurred in sampled segments by experts. These data represent the presence-absence records from 52 sites monitored in 2014. In 2014, we identified the species for 7138 segments in total and 68 species occurred. We are continuing to monitor and intend to update the dataset with new observations hereafter. Our dataset will help people to recognize the status and dynamics of avian assemblage inside the evacuation zone, and will contribute to promote open science in avian ecological studies.

In 2011, the Fukushima Daiichi Power Plant accident resulted in the evacuation of about 81,000 people from the evacuation zone, which suffered from high levels of radioactive contamination. Large-scale and long-term land abandonment can cause changes in species assemblages. Despite the extensive global attention this incident received, open and spatially-explicit datasets of mammal fauna from Fukushima remain quite limited. We established a continuous monitoring protocol using camera traps for mammals both inside and outside the evacuation zone; this paper presents our first dataset. These data represent the monitoring results from 45 camera traps from May 2014 to October 2014, including the location and actuation time of each camera, and the list of video records. After the publication of this initial data paper, we intend to continue monitoring until 2023 and the dataset will be hereafter updated with new observations.

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Although dragonflies are excellent environmental indicators for monitoring terrestrial water ecosystems, automatic monitoring techniques using digital tools are limited. We designed a novel camera trapping system with an original dragonfly detector based on the hypothesis that perching dragonflies can be automatically detected using inexpensive and energy-saving photosensors built in a perch-like structure. A trial version of the camera trap was developed and evaluated in a case study targeting red dragonflies (Sympetrum spp.) in Japan. During an approximately 2-month period, the detector successfully detected Sympetrum dragonflies while using extremely low power consumption (less than 5 mW). Furthermore, a short-term field experiment using time-lapse cameras for validation at three locations indicated that the detection accuracy was sufficient for practical applications. The frequency of false positive detection ranged from 17 to 51 over an approximately 2-day period. The detection sensitivities were 0.67 and 1.0 at two locations, where a time-lapse camera confirmed that Sympetrum dragonflies perched on the trap more than once. However, the correspondence between the detection frequency by the camera trap and the abundance of Sympetrum dragonflies determined by field observations conducted in parallel was low when the dragonfly density was relatively high. Despite the potential for improvements in our camera trap and its application to the quantitative monitoring of dragonflies, the low cost and low power consumption of the detector make it a promising tool.

The Fukushima Daiichi power plant accident led to large‐scale and long‐term evacuation zones in which usual land‐use activities such as farming have been stopped. In particular, the loss of irrigated rice paddies is hypothesized to have seriously impacted freshwater biodiversity. In 2014, we started acoustic monitoring of frogs by using digital voice recorders in and around the evacuation zone. For the monitoring project, 52 and 57 monitoring sites were located within schoolyards (including those that had been converted into community centers) to examine the frog assemblages in the urban and rural landscapes of the region in 2014 and 2015, respectively. At each site, a digital voice recorder was installed during the period from May to July, and we recorded 10 min a day at night using a timed‐recording mode. We divided the audio data into 20‐s segments and identified species recorded in segments sampled from late May to late June (partly in early July). We identified eight frog species from 1,962 audio segments in total (correspond to 4 days per year in principal). For each species, intensity of calling at four levels was also recorded as an index of abundance. We are continuing to monitor and intend to update the dataset with new observations hereafter. Our dataset will support scientists and experts in recognizing the status and dynamics of anuran assemblages in and around the evacuation zone and will contribute to the promotion of open science. The complete data set for this abstract published in the Data Paper section of the journal is available in electronic format in MetaCat in JaLTER at http://db.cger.nies.go.jp/JaLTER/metacat/metacat/ERDP-2020-12.1/jalter-en.