Bats adjust echolocation and social call design as a response to urban environments

Behavioral traits play a major role in the successful adaptation of wildlife to urban conditions. We investigated and compared the acoustic behavior of free ranging bats in rural (Havelland, Brandenburg) and urban (Berlin city center) green areas (n = 6 sites) to assess possible effects of urbanization on bat vocalizations using automated real-time recordings from May to October 2020 and 2021. We show that foraging and social call activity of commonly occurring bat species was lower in urban areas compared to rural areas. We present data on rural-urban variation in acoustic parameters of echolocation and Type D social calls (produced during flight) using the example of the common pipistrelle Pipistrellus pipistrellus. Calls from urban sites revealed significantly higher end and peak frequencies compared to rural site calls. In addition, urban social calls present a higher degree of complexity as they structurally differed from rural social calls with regard to assemblage and number of call components. Moreover, urban social calls were emitted in a presumably different context than rural calls: antagonistic social calls in urban areas were detected throughout the year and in the acoustic absence of conspecifics and heterospecifics. Our results provide evidence for the ability of P. pipistrellus to modulate temporal and spectral features of echolocation and social calls, as well as patterns of social call production, in order to compensate for constraints imposed by the urban acoustic environment. We suggest that this acoustic behavioral plasticity plays a major role in the degree of adaptation of insectivorous bats to urban habitats.Peer Reviewe

Human–Wildlife Conflicts across Landscapes—General Applicability vs. Case Specificity

Here, we address the question of if/to what extent human–wildlife conflict (HWC) can be reduced or mitigated by supra-regional or even global approaches, or whether case- and region-specific strategies are necessary. First, we try to shift the perspective from humans towards wildlife and regard modern era (near) extinctions of selected wildlife species as an ultimate expression of HWC. We then reflect on the legitimacy of ecosystem comparisons beyond the borders of biogeographical regions—an important prerequisite for global approaches. In the following, we present two case scenarios that exemplarily illustrate the topic from different perspectives: carnivore–livestock conflicts (classical view, human perspective) and wind turbine-induced mortality of bats (wildlife perspective, rarely regarded as a form of HWC). On this basis, we try to develop a framework that enables a global approach, while adequately considering case- and region-specificity. We think that a globally valid and generally approachable dimension can be defined, as long as there is a natural link: in the present case the established monophyly of the orders Carnivora and Chiroptera, i.e., representatives descending from common ancestors, thus sharing common ecological features. This natural relationship among all representatives of a systematic group (specification of the “wildlife” concept) is key for the development of an overarching strategy that can be adjusted to a specific case.Peer Reviewe

Spatial Behavior and Habitat Use of Two Sympatric Bat Species

Few studies refer to ecological differences of genetically close and morphologically almost identical insectivorous bat species. However, this information is indispensable for effective and sustainable nature conservation strategies. This study aims at investigating differences in the spatial ecology of the long-eared bat species Plecotus auritus and Plecotus austriacus in a typical cultural landscape of Brandenburg, where the two species occur sympatrically. The reconstruction of the prey spectrum revealed that P. auritus and P. austriacus strongly overlapped in their diet. Our results suggest that resource partitioning is based on using different foraging habitats. While radio-tracked females of P. auritus were strongly associated with woodland patches resulting in small-scale activity areas of only few square kilometers, activity areas of P. austriacus encompassed a large-scale matrix of grassland habitats in the magnitude of a small town. Based on these results, we identify priority conservation needs for the two species to ensure that these differences in the spatial behavior and habitat use can be adequately taken into account for future nature conservation efforts. Abstract Movement behavior and habitat use of the long-eared bat species Plecotus auritus and Plecotus austriacus were studied in the Havelland region in Brandenburg (Germany). Data collection included mist-netting, radiotelemetry, reconstruction of prey items, and monitoring of roosting sites. Body measurements confirm a high degree of phenotypic similarity between the two species. Total activity areas (100% Minimum Convex Polygons, MCPS) of Plecotus austriacus (2828.3 ± 1269.43 ha) were up to five-fold larger compared to Plecotus auritus (544.54 ± 295.89 ha). The activity areas of Plecotus austriacus contained up to 11 distinct core areas, and their mean total size (149.7 ± 0.07 ha) was approximately three-fold larger compared to core areas of Plecotus auritus (49.2 ± 25.6 ha). The mean distance between consecutive fixes per night was 12.72 ± 3.7 km for Plecotus austriacus and 4.23 ± 2.8 km for Plecotus auritus. While Plecotus austriacus was located most frequently over pastures (>40%) and meadows (>20%), P. auritus was located mostly within deciduous (>50%) and mixed forests (>30%) in close vicinity to its roosts. Roost site monitoring indicates that the activity of P. austriacus is delayed relative to P. auritus in spring and declined earlier in autumn. These phenological differences are probably related to the species’ respective diets. Levins’ measure of trophic niche breadth suggests that the prey spectrum for P. auritus is more diverse during spring (B = 2.86) and autumn (B = 2.82) compared to P. austriacus (spring: B = 1.7; autumn: B = 2.1). Our results give reason to consider these interspecific ecological variations and species-specific requirements of P. auritus and P. austriacus to develop adapted and improved conservation measures.Peer Reviewe

Using Machine-Learning for the Damage Detection of Harbour Structures

The ageing infrastructure in ports requires regular inspection. This inspection is currently carried out manually by divers who sense the entire below-water infrastructure by hand. This process is cost-intensive as it involves a lot of time and human resources. To overcome these difficulties, we propose scanning the above and below-water port structure with a multi-sensor system, and by a fully automated process to classify the point cloud obtained into damaged and undamaged zones. We make use of simulated training data to test our approach because not enough training data with corresponding class labels are available yet. Accordingly, we build a rasterised height field of a point cloud of a sheet pile wall by subtracting a computer-aided design model. The latter is propagated through a convolutional neural network, which detects anomalies. We make use of two methods: the VGG19 deep neural network and local outlier factors. We showed that our approach can achieve a fully automated, reproducible, quality-controlled damage detection, which can analyse the whole structure instead of the sample-wise manual method with divers. We were able to achieve valuable results for our application. The accuracy of the proposed method is 98.8% following a desired recall of 95%. The proposed strategy is also applicable to other infrastructure objects, such as bridges and high-rise buildings

A combination of temperature and urea sanitization of blackwater : optimization of a full scale system in Hölö, Sweden

There are an abundance of environmental problems in the world today, some of which can be traced back to a lack of proper sewage treatment. Human toilet waste, also called blackwater, is discharged untreated into the environment where it can contaminate water bodies, including drinking water sources. However, blackwater is an excellent source of plant available nutrients, and can be used as a fertilizer after proper treatment. The risks involved in the reuse of blackwater include pathogenic microorganisms, heavy metals, and pharmaceutical substances. This study however focuses only on the inactivation of pathogenic microorganisms during blackwater treatment. The aim of this study was to optimize a current blackwater treatment method at a plant in Hölö, Sweden, and confirm that the treated blackwater reached the required microbial reductions based on SPCR 178 (SP, 2012). The current method treats 30 m³ of blackwater within 2 weeks through an increase of the materials temperature to 40°C and then the addition of 0.5% urea, based on the wet weight. The method in this study treats 160 m³ with a similar treatment procedure, but rather than heating all of the treated blackwater only one third (60 m³) was heated to 40°C and then mixed with the other two thirds (100 m³) which remain at ambient temperature. After the blackwater was mixed, 1% urea (based on the wet weight) was stirred in to ensure an even distribution, after which the treatment lasted 21 days. The study was performed twice (set 1 and set 2), with samples being taken six times per set. Samples were analyzed for physiochemical properties (temperature, pH, total nitrogen and ammonia concentrations) and microorganisms (Ascaris suum eggs, Enterococcus spp., Salmonella spp., thermo tolerant coliform bacteria/E.coli, f-RNA bacteriophages, and somatic coliphages). The temperature, after the heated blackwater was mixed in with the blackwater at ambient temperature, started at approximately 17°C and then decreased to around 11°C by day 21. After the addition of 1% urea, the total-Nitrogen concentration rapidly increased and then remained constant. The pH increased during the first week and then reached a steady state. The total ammonia Nitrogen (TAN) also increased over the 21 days, appearing to reach a somewhat steady state in the last week. Salmonella spp. reached the required inactivation (absent in 25 g of sample based on the wet weight) by days 4 and 2 in sets 1 and 2 respectively. TtC/E.coli reached below the detection limit (1 CFU ml⁻¹) by day 7 in both sets, which is below the <1000 CFU g⁻¹ (TS) required for the certification. The only microorganism which didn’t reach its required end-product concentration (<1000 CFU g⁻¹ [TS]) by day 21 was Enterococcus spp. Further studies using a combination of different amounts of heated and unheated blackwater in addition to different urea doses are needed to find the ideal treatment of the blackwater, where the required sanitization goals are met using the most cost efficient parameters