Assessment of in situ nest decay rate for chimpanzees (Pan troglodytes ellioti Matschie, 1914) in Mbam-Djerem National Park, Cameroon : implications for long-term monitoring

Accurate assessment of great ape populations is a prerequisite for conservation planning. Indirect survey methods using nest and dung, and a set of conversion parameters related to nest decay rates, are increasingly used. Most surveys use the standing crop nest count (SCNC) method, whereby nests are counted along transects and the estimated nest density is converted into chimpanzee density using an often non-local nest decay rate. The use of non-local decay rate is thought to introduce substantial bias to ape population estimates given that nest decay rates vary with location, season, rainfall, nest shape, and tree species used. SCNC method has previously been applied in Mbam-Djerem National Park (MDNP) in Cameroon, for chimpanzee surveys using a non-local nest decay rate. This current study aimed to measure a local nest decay rate for MDNP and implications for chimpanzee population estimates in the MDNP. The mean nest decay rate estimated using a logistic regression analysis was 127 [95% CI (100-160)] days. Moreover, the results suggested that rainfall strongly infuenced the nest decay rate over the early stage of the lifetime of the nests. The study confrms that estimates of chimpanzee density and abundance using non-local decay rates should be treated with caution. Our research emphasized the importance of using local nest decay rates and other survey methods which do not depend on decay rates to obtain more accurate estimates of chimpanzee densities in order to inform conservation strategies of these great apes in MDNP

Bat echolocation plasticity in allopatry: a call for caution in acoustic identification of Pipistrellus sp.

Animals modify their behaviours and interactions in response to changing environments. In bats, environmental adaptations are reflected in echolocation signalling that is used for navigation, foraging and communication. However, the extent and drivers of echolocation plasticity are not fully understood, hindering our identification of bat species with ultrasonic detectors, particularly for cryptic species with similar echolocation calls. We used a combination of DNA barcoding, intensive trapping, roost and emergence surveys and acoustic recording to study a widespread European cryptic species complex (Pipistrellus pipistrellus and Pipistrellus pygmaeus) to investigate whether sibling bat species could exhibit extreme echolocation plasticity in response to certain environmental conditions or behaviours. We found that P. pygmaeus occupied the acoustic niche of their absent congeneric species, producing calls with P. pipistrellus’ characteristic structure and peak frequencies and resulting in false positive acoustic records of that species. Echolocation frequency was significantly affected by the density of bats and by maternity rearing stage, with lower frequency calls emitted when there was a high density of flying bats, and by mothers while juveniles were non-volant. During roost emergence, 29% of calls had peak frequencies typical of P. pipistrellus, with calls as low as 44 kHz, lower than ever documented. We show that automatic and manual call classifiers fail to account for echolocation plasticity, misidentifying P. pygmaeus as P. pipistrellus. Our study raises a vital limitation of using only acoustic sampling in areas with high densities of a single species of a cryptic species pair, with important implications for bat monitoring

Watching wildlife in Cabo Polonio, Uruguay: tourist control or auto-control?

Cabo Polonio (Uruguay) is a popular but atypical centre for beach vacations, because tourists spend days without electricity, running water and vehicle. There is a continental pinniped colony that acts as secondary attraction, but there is not direct control over tourist visits to the rookery. Our objective was to evaluate the experience of visitors to this pinniped colony. We used questionnaires to determine the information used by tourists and to analyse their attitudes towards the colony conservation. To validate questionnaires, we also conducted direct observations of the tourist-pinniped interactions. Less than 15% of tourists received information, which was provided by local people. Most tourists saw the rookery as an important touristic attraction. There was total consensus about the requirement for wildlife information. Despite the lack of active supervision, most people behaved properly and complied with conservation measures: the probability that a tourist crossed the fence during a visit was only 0.002 (17 crosses in 902 hours). This positive attitude is possible related to the fact that tourists in Cabo Polonio, accept the discomfort of living without social commodities and welcome the closeness with nature. It is expected that most people will have a spontaneous predisposition to take care of nature.Fil: Tuneu Corral, Carme. Universidad de Barcelona; EspañaFil: Szteren, Diana. Universidad de la República; UruguayFil: Cassini, Marcelo Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina. Universidad Nacional de Luján; Argentin

Living on the edge: thermoregulatory behaviour of South American sea lions, Otaria flavescens, at the northern limit of their Atlantic distribution

Terrestrial reproduction presents a thermoregulatory challenge for marine mammals, especially in a context of global warming. Pinnipeds, especially otariids, differ from other marine mammals in that most reproductive processes occur on land. Rocky rookeries rarely provide thermoregulatory resources (shade, pools and wet sand), so pinnipeds reduce thermal stress through thermoregulatory behaviour such as flipper exposure, flipper movement and maintenance of individual distance. Our objective was to analyse climate correlates of thermoregulatory behaviour of Southern sea lions Otaria flavescensin a colony located at the warmest end of its northern distribution on the Atlantic coast of South America. We conducted summer behavioural observations of juveniles/sub-adult (less than 150 kg) and adult (300 kg) males in the Cabo Polonio rookery, Uruguay. Solar radiation and humidity were positively correlated with thermoregulatory behaviour of sea lions, while ambient temperature had a marginal effect and wind speed had no significant effect. There were no statistically significant differences between age classes in thermoregulation activity. These and previous results on thermoregulatory behaviour of pinnipeds open the possibility that pinnipeds can be limited in abundance or distribution if climate change alters solar radiation in terrestrial rookeries during the breeding season.Fil: Tuneu Corral, Carme. Universidad de Barcelona; EspañaFil: Szteren, Diana. Universidad de la República; UruguayFil: Cassini, Marcelo Hernan. Universidad Nacional de Luján; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentin

Ecological indices in long-term acoustic bat surveys for assessing and monitoring bats' responses to climatic and land-cover changes

Bats are well known for playing an important role in several ecosystem services such as arthropod population control, insect pest suppression in agricultural systems and vector disease control, but also for acting as ecological indicators. Their population dynamics are strongly linked to environmental variations and, in some cases, reflect the health status of ecosystems. Hence, some species have an excellent potential as ecological indicators due to their sensitivity to ecosystem changes. Despite the general decrease of many bat populations worldwide and the recent upsurge in the use of autonomous acoustic detectors, the acoustic monitoring of bat assemblages is still an emerging field in bat research and conservation. Probably due to a general lack of methodological standards and the lack of common ecological indices, few long-term bat acoustic monitoring programs are currently active and data is rarely shared and compared between regions. In this study we propose and adapt a set of different ecological indices that can be used in acoustic surveys designed to detect changes in bat diversity, activity and assemblage composition, all of which can be linked to species’ climatic and habitat-related preferences. Using a dataset collected during three years of bat monitoring in Catalonia (NE Iberian Peninsula), we used three traditional indices (richness, activity and Shannon diversity) and developed four new ecological indices (Community Thermal Index, Community Precipitation Index, Community Openness Index and Community Specialization Index) that enabled us to study bat communities and compare them at different spatial and temporal scales. Here, we demonstrate the applicability of these indices in bat monitoring programs. We also provide a consistent tool for generating easy-to-interpret ecological indices when monitoring the short- and long-term responses of bats under the current scenario of global change. Using standardized protocols and robust ecological indices enables studies and datasets to be compared, which in turn promotes the development of proper management and conservation measures via international cooperation

Assessment of in situ nest decay rate for chimpanzees (Pan troglodytes ellioti Matschie, 1914) in Mbam-Djerem National Park, Cameroon : implications for long-term monitoring

Accurate assessment of great ape populations is a prerequisite for conservation planning. Indirect survey methods using nest and dung, and a set of conversion parameters related to nest decay rates, are increasingly used. Most surveys use the standing crop nest count (SCNC) method, whereby nests are counted along transects and the estimated nest density is converted into chimpanzee density using an often non-local nest decay rate. The use of non-local decay rate is thought to introduce substantial bias to ape population estimates given that nest decay rates vary with location, season, rainfall, nest shape, and tree species used. SCNC method has previously been applied in Mbam-Djerem National Park (MDNP) in Cameroon, for chimpanzee surveys using a non-local nest decay rate. This current study aimed to measure a local nest decay rate for MDNP and implications for chimpanzee population estimates in the MDNP. The mean nest decay rate estimated using a logistic regression analysis was 127 [95% CI (100-160)] days. Moreover, the results suggested that rainfall strongly infuenced the nest decay rate over the early stage of the lifetime of the nests. The study confrms that estimates of chimpanzee density and abundance using non-local decay rates should be treated with caution. Our research emphasized the importance of using local nest decay rates and other survey methods which do not depend on decay rates to obtain more accurate estimates of chimpanzee densities in order to inform conservation strategies of these great apes in MDNP

Concurrent Butterfly, Bat and Small Mammal Monitoring Programmes Using Citizen Science in Catalonia (NE Spain): A Historical Review and Future Directions

The Biodiversity and Bioindicators research group (BiBIO), based at the Natural Sciences Museum of Granollers, has coordinated four long-term faunal monitoring programmes based on citizen science over more than two decades in Catalonia (NE Spain). We summarize the historical progress of these programmes, describing their main conservation outputs, the challenges overcome, and future directions. The Catalan Butterfly Monitoring Scheme (CBMS) consists of a network of nearly 200 recording sites where butterfly populations have been monitored through visual censuses along transects for nearly three decades. This programme provides accurate temporal and spatial changes in the abundance of butterflies and relates them to different environmental factors (e.g., habitat and weather conditions). The Bat Monitoring Programme has progressively evolved to include passive acoustic monitoring protocols, as well as bat box-, underground- and river-bat surveys, and community ecological indices have been developed to monitor bat responses at assemblage level to both landscape and climatic changes. The Monitoring of common small mammals in Spain (SEMICE), a common small mammal monitoring programme with almost 80 active live-trapping stations, provides information to estimate population trends and has underlined the relevance of small mammals as both prey (of several predators) and predators (of insect forest pests). The Dormouse Monitoring Programme represents the first monitoring programme in Europe using specific nest boxes for the edible dormouse, providing information about biological and demographic data of the species at the southern limit of its distribution range. The combination and complementarity of these monitoring programmes provide crucial data to land managers to improve the understanding of conservation needs and develop efficient protection laws