Description: Environmentalists and authorities responsible for road safety are trying to reduce the number of wildlife collisions with vehicles (WCV) worldwide. Roe deer are the most common large animal involved in WCV in Europe. This article discusses the distribution of 2010 wildlife-vehicle collisions involving roe deer (WVRD) in Lithuania in 2013 and 2014. The collisions were analyzed in terms of monthly and daily data for each month separately, and the results are compared with the time of sunrise and sunset in Lithuania. By analyzing trends of natural factors that influence the number of collisions we show that the frequency of WVRD is strongly correlated with seasonal and yearly changes in sunrise and sunset. This research shows that these natural factors are extremely important for the dynamics of WVRD. Future analysis of these factors and application of appropriate preventative measures should significantly reduce the risk of collision between vehicles and roe deer.

Description: Evergreen conifers Abies mariesii and A. veitchii codominate in the subalpine zone in central Japan. This study compared the photosynthetic light response curves and related leaf traits of 1-year-old needles between the two species to examine whether photosynthetic traits of A. veitchii are more favorable for growth in bright conditions than those of A. mariesii . Saplings of the two species were sampled at forest edge (FE) and forest understory (FU). FE saplings of the two species showed more shade-intolerant traits (i.e., lower initial slope of photosynthesis light response curve, greater light compensation point and dark respiration rate) than FU saplings. Maximum photosynthetic rate and leaf nitrogen concentration were greater in A. veitchii than A. mariesii for both FE and FU saplings. Photosynthetic nitrogen use efficiency (PNUE) was also greater in A. veitchii than A. mariesii . On the contrary, leaf mass per area was greater in A. mariesii than A. veitchii for both FE and FU saplings. Therefore, this study showed that photosynthetic traits of A. veitchii are more favorable for growth in bright conditions compared with A. mariesii , and A. mariesii has more robust needles at the expense of PNUE.

Description: The measurement of heavy metal concentrations in plants is important both for determining their ability to remove these pollutants from the air to increase its quality, and for the monitoring of air quality. Previous studies have mostly focused on the use of annual leaves of broadleaved species as biomonitors. In this study, the aim was to determine the heavy metal accumulation of the perennial needles of some conifers. In almost all the species studied, concentrations of heavy metals were found to increase with the age of the tree, but this increase was not linear. There were significant differences between the species in terms of heavy metal accumulation. The highest concentrations were for Fe in Pinus nigra , Zn in Picea pungens , Pb in Pinus sylvestris , and for all the other heavy metals in Abies bornmülleriana . This study indicates that A. bornmülleriana is particularly useful as a biomonitor for many heavy metals, and also has the potential to remove heavy metals from the air.

Description: The “Caddisfly Watch” program proposes the use of larvae of the caddisfly genus Stenopsyche (Trichoptera: Stenopsychidae) to monitor the radioactive cesium ( 137 Cs) pollution, including that of suspended solids, in river environments, as a simple method was essential for this following the Fukushima nuclear disaster in March 2011. A variety of aquatic organisms were collected from rivers in Japan in 2012 and their levels of radioactive Cs measured. Amongst all the organisms collected, the highest concentrations of 137 Cs were observed in caddisfly larvae. These larvae occur at a high density and can be collected at regular intervals in most rivers throughout Japan. It is proposed that caddisfly larvae can be used as bioindicators of radioactive Cs contamination in rivers, as their temporal and spatial changes are easily assessed.

Description: In mountainous areas, the landscape spatial pattern is affected by topography and human activities. To better understand topographic influences on the vegetation structure in the landscape mosaic and interpret the ecological implications of spatial patterns, the relationships between topographic features and landscape pattern indices (LPIs) should be addressed. The objective of this study is to address the effects of topography on LPIs (both planimetric and surface LPIs) by integrating spatial analysis and gradient analysis. To fulfill these objectives, two different mountain research sites located in the Lancang River watershed were chosen, both planimetric and surface landscape metrics were used to quantify natural category (NC) and anthropogenic category (AC) patterns, and the redundancy ordination gradient method was used to address the relationship between LPIs (planimetric and surface metrics) of NC and AC patterns and topographic attributes. The results suggest that topographic attributes play a prominent role in structuring the landscape mosaic. Elevation is a key factor for NC and AC patch patterns in the study area. The results indicate that the fragmentation and isolation of NC patterns increase as elevation decreases. In contrast, the fragmentation and isolation of AC patterns decrease as elevation decreases.

Description: The Great East Japan Earthquake that occurred on 11 March 2011 generated a series of massive tsunami waves that caused severe damage to the Fukushima Daiichi Nuclear Power Plant, following which large amounts of radioactive materials were discharged from the power plant into the environment. Given the recently developed technologies for unmanned helicopters and their potential application in airborne radiation monitoring, we developed a radiation monitoring system for aerial use. We then used unmanned helicopters to measure the radiation level in areas with soil contaminated by radiocesium emitted from the nuclear power plant to evaluate the ambient dose rate distribution around the site. We found that in dry riverbeds downstream of the highly contaminated watershed, especially in the upstream parts, that the ambient dose rate was higher than that in protected inland areas. In addition, we carried out soil sampling in dry riverbeds. The soil sample data agreed with the results obtained from the unmanned helicopter. A possible scenario is that river sediment and adjacent soil containing radioactive materials were carried downstream due to an event such as a rise in water level caused by, e.g., a typhoon, and that these remained in the riverbed after the water drained away. The vertical profile of radiocesium in the soil and the measurements of river sediment at river mouth areas corroborated this scenario.

Description: This study examined 137 Cs detachment from needle litter of Japanese cedar ( Cryptomeria japonica ) through leaching and decomposition in a headwater stream located 45 km from Fukushima Daiichi Nuclear Power Plant. We placed litter bags in pools and riffles and removed them after 4, 15, 75, 150, and 240 days. The 137 Cs activity concentration in litter collected after 4 and 15 days was 48–72 % of the initial 137 Cs activity concentration in litter. The 137 Cs activity concentration in litter after 240 days in the pools decreased by 26 %, while that in litter of riffles decreased by 9 % compared with the initial 137 Cs activity concentration. The dry weight of litter became 71 and 86 % of initial weight after 75 days, and from 32 to 51 % after 150 days. The decay coefficient of litter ( k  = 0.0060) in the riffles was 1.6-fold higher than that in the pools ( k  = 0.0037). The greater decrease in litter weight with longer submergence time was possibly associated with a combination of leaching and decomposition, in particular in litter that was submerged for 100 days in the water column. The difference in the rate of decomposition and 137 Cs detachment from litter between the riffles and pools was due to the substrate and flow conditions at the litter bag sites. Examining the different patterns of 137 Cs detachment from litter among channel morphologies is necessary for comprehending the mechanisms of 137 Cs accumulation in aquatic biota. The findings of this study suggest that elucidating leaching and decomposition processes in litter of stream channels is important for understanding 137 Cs dynamics in forested headwater ecosystems.

Description: This study investigated vegetation and soil properties in a beaver-created freshwater wetland located on the Coastal Plain of Virginia near Washington, DC. We focused on the associations among floristic quality, soil physicochemistry, denitrification, and hydrologic conditions of the wetland to understand links between the effects of beaver engineering and ecosystem function. The floristic quality assessment index (FQI) and denitrification are two important indicators often used to examine overall habitat quality and ecosystem functioning of a wetland. Samples were collected from ten plots (10 m × 10 m each) in August 2014. Vegetation attributes included total percent cover, species richness ( S ), diversity, FQI, and prevalence index (PI). Soil attributes included organic matter (OM), total carbon, total nitrogen, gravimetric moisture (GM), pH, bulk density ( D b ), and denitrification potential (DP). FQI was greater in the higher of the two standing water level categories, where D b was lower, and was negatively associated with D b but no other soil nutrient properties. DP was positively associated with soil nutrients, OM, and GM, but not with measured vegetation attributes nor standing water levels. We found higher soil GM, lower plant community PI, and lower plot S in this study compared to our previous study, with no changes to other vegetation or soil attributes, indicating enduring beaver activity and a resilient plant community. The outcome of the study includes regression models that best explain the association between structural and functional attributes of the ecosystem, which can be applicable to the study of other beaver-created wetlands. The study also provides partial evidence for the notion that low-lying areas dug out by beaver positively impact the FQI of wetlands.

Description: We examined the cesium-137 ( 137 Cs) contamination of river food webs in a gradient of initial fallout deposition (net density estimates 2.5–3.5 months after the Fukushima Daiichi Nuclear Power Plant accident in March 2011), in Fukushima Prefecture, Japan. Litter, aquatic insects, and salmonid fish were collected in five headwater stream reaches (watershed-average fallout density, 368.1–1398.4 kBq/m 2 ) for the measurement of 137 Cs concentration and stable isotope ratios of carbon (δ 13 C) and nitrogen (δ 15 N) in June 2014. The stable isotope ratios suggested that the detrital food chain was a dominant energy pathway in rivers originating from a basal resource (litter) to primary (aquatic insects) and secondary (fish) consumers. The 137 Cs concentration decreased with an increase in the trophic level, with the highest value for litter (10930 ± 5381 Bq/kg, mean ± SD), the lowest for fish (2825 ± 2451 Bq/kg), and the intermediate one for dominant (numerically and biomass-wise) detritivorous insect, Ephemera japonica McLachlan (4605 ± 1970 Bq/kg). 137 Cs concentrations of three trophic levels were linearly predicted by the initial fallout amount of 137 Cs. The evacuation of the gut contents of E. japonica during field experiments led to a reduction in their 137 Cs concentration by approximately 50% within 1–2 day(s) without loss of body weight. This suggested that a substantial portion of 137 Cs contamination of E. japonica was derived from highly contaminated fine solids deposited in depositional habitats at a disproportionately high density. Overall, the initial fallout amount of 137 Cs was helpful in roughly predicting the contamination levels of headwater river-riparian ecosystems with the detrital food chain as a dominant energy pathway. Long-term monitoring of the dynamics and fates of 137 Cs associated with fine organic and inorganic particulates appears important for better prediction of 137 Cs contamination of food webs in forested headwater streams.