A comparison of four different methods to estimate population size of Alpine marmot (Marmota marmota)

Obtaining reliable information on animal abundance in mountainous landscapes is challenging. Highly heterogeneous habitats tend to reduce detection probabilities, and the three-dimensional, rugged nature of the terrain poses severe limits to the fulfilment of a number of assumptions underlying several statistical methods. In this study, we aimed to compare the performance of 4 different methods to estimate population size of Alpine marmot (Marmota marmota), a highly social semifossorial rodent widely distributed on the European Alps. Between May and August 2015, in a study area within the Stelvio National Park (Italy) we conducted 8 sessions of capture-mark-recapture, 6 sessions of mark-resight from vantage points, 8 sessions of line distance sampling along 4 transects, and 2 sessions using double-observer methods from vantage points. The minimum number of animals alive, obtained during the mark-resight surveys, was n=54 individuals. Capture-mark-recapture models estimated a population size of n=56 individuals [95% CI (45,87)]; similar, but more precise estimates were obtained with the mark-resight approach {Bowden’s estimator: n=62 [95% CI (54,71)]; Poisson log-normal estimator: n=62 [95% CI (55,69)]}. Line distance sampling and double-observer methods were severely biased low {Line distance sampling: n=24 individuals [95% CI (19,31)]; Independent double-observer: n=24 [95% CI (22, 35)]; Dependent double-observer: n=15 [95% CI (15,20)]}. Our results suggest that the probabilistic approach based on marked individuals yielded fairly robust estimates of population size. The underestimates obtained using distance sampling and double-observer methods were likely due to the violation of some underlying assumptions. While the topography of the mountainous landscape makes it difficult to randomize the sampling scheme, the semifossorial behaviour of the target species is likely to lower the detection probabilities and violate the assumption of perfect detection on the transect

Shortlisting by Incomplete Descriptions: The Power of Combination.

In this paper we make use of a particular technique of data analysis to empirically study the effect of joint attributes presentation in a multi-step process of choice, in which consumers first use a simple method for shortlisting, then proceed with a closer inspection of a restrict number of alternatives. Shortlisting is based on an incomplete description of the attributes of an alternative. We focus, in particular, on the presentation couples of attributes. The mathematical framework we used is the generalized spectral analysis. We tested this method on data collected through an ad hoc survey. Thanks to this powerful machinery we were able to identify the attraction single attributes have, from the effect of their combination. The use of generalized spectral analysis to decompose data on preferences is totally new. The decomposition allows us to underline two effects: the first and second order effect. The first order effect measures the average attraction that a single feature has when it is coupled with a second one. The second order effect detects the positive (or negative) power of combination of two coupled attributes. We present here a particular case, the choice of a car, among the ones we studied, to show how the method can be used, and its power. A particular emphasis will be given to gender differences in the evaluation of car attributes in the choice process.

Shortlisting by Incomplete Descriptions: The Power of Combination.

In this paper we make use of a particular technique of data analysis to empirically study the effect of joint attributes presentation in a multi-step process of choice, in which consumers first use a simple method for shortlisting, then proceed with a closer inspection of a restrict number of alternatives. Shortlisting is based on an incomplete description of the attributes of an alternative. We focus, in particular, on the presentation couples of attributes.x10The mathematical framework we used is the generalized spectral analysis. We tested this method on data collected through an ad hoc survey. Thanks to this powerful machinery we were able to identify the attraction single attributes have, from the effect of their combination.x10The use of generalized spectral analysis to decompose data on preferences is totally new. The decomposition allows us to underline two effects: the first and second order effect.x10The first order effect measures the average attraction that a single feature has when it is coupled with a second one. The second order effect detects the positive (or negative) power of combination of two coupled attributes. We present here a particular case, the choice of a car, among the ones we studied, to show how the method can be used, and its power. A particular emphasis will be given to gender differences in the evaluation of car attributes in the choice process.

A field test of unconventional camera trap distance sampling to estimate abundance of marmot populations

The increasing use of remote motion‐sensitive photography recently led to an extension of distance sampling (DS) to accommodate camera trap data. Camera trap distance sampling (CTDS) has been proposed as a promising tool to estimate animal abundance, if temporally limited availability for detection is accounted for. However, the performance of CTDS in different field situations, and its reliability when single still images are used instead of videos or bursts of images remain untested. We used Alpine marmots Marmota marmota in the Stelvio National Park (Italy) to address three aims: 1) compare estimates of availability bias‐corrected CTDS when using single still images with different set‐ups to define sampling effort. For the 'user‐manual' set‐up we used values of θ [angle of view] and t∗ [recovery time, i.e. the shortest interval at which an animal can be detected] specified by the camera user manual. For the 'empirical' set‐up we estimated θ and t∗ empirically. 2) Compare estimates of CTDS and line DS, both corrected for availability bias based on marmot behavior. 3) Compare estimates of CTDS corrected for availability bias with estimates obtained with capture–mark–recapture (CMR), accounting for the effective trapped area. Our results suggest that: 1) CTDS with 'user‐manual' set‐up underestimated population size compared to the 'empirical' set‐up; 2) 'empirical' CTDS estimates were similar to those of line DS, but CTDS had lower precision; 3) availability bias‐corrected CTDS underestimated abundance compared to CMR. Assessing camera settings empirically is crucial to reduce bias in CTDS estimators when single still images are used. Videos should be preferred as they allow choosing predefined snapshot moments and do not rely on settings that cannot be changed. Overall, our results support the use of CTDS as an alternative to DS, although proper availability‐bias corrections and many cameras are needed to ensure accuracy and acceptable precision

Browsing intensity as an index of ungulate density across multiple spatial scales

Large herbivores can profoundly influence terrestrial ecosystems. Through browsing, for example, they can impact forest regeneration with consequences for both plant and animal species. Understanding the drivers of ungulate browsing is therefore crucial from a conservation and management standpoint. Browsing is generally thought to be affected by ungulate density, such that increased density leads to greater browsing probability. As a result, browsing has been suggested as an indicator of ungulate density. While most studies investigated long-term browsing impact of ungulates in single study areas, few of them focused on different spatial scales using multiple replications in time and space. In this study we took advantage of 25 years of browsing data within the Stelvio National Park (central Italian Alps) derived from several populations of red deer and modelled the ratio of browsing on conifers (calculated as browsed conifers divided by total number of conifers) as a function of two different density indices at different spatial scales and a set of environmental covariates. Specifically, we investigated whether variations in red deer density at different spatial scales reflect variations in browsing probability. The results suggest that as deer density increased, the ratio of browsing increased at all spatial scales, at times mediated by shrub species diversity. Density was a consistent driver of browsing probability within all deer populations, while the effect of confounding variables was statistically unclear as they yielded conflicting results for the different populations, failing to find common patterns. This study highlights that density at different spatial scale is an important predictor of browsing probability, suggesting that browsing could be a reliable indicator of variations in ungulate density. In turn, as browsing can map small- and large-scale density variations, pattern of browsing impact may be a useful tool to investigate small- and large-scale changes in red deer densities due to disturbance factors such as human activities or the presence of large predators

Environmental and pathological factors affecting the hatching success of the two northernmost loggerhead sea turtle (Caretta caretta) nests

In recent years, the report of loggerhead sea turtle (Caretta caretta) Mediterranean nesting range has expanded together with new records of nests becoming northward on the Italian coastline of the Tyrrhenian and Adriatic seas. These areas are characterized by intensive human activities, such as tourism, fishery, and marine traffic, all possibly involved in the influence of the use of coastal habitat by marine species. These anthropic threats, in addition to the natural ones and the changing environmental characteristics of the beach, may influence the growth of microorganisms causing hatching failures. Among microorganisms, fungal infection by the genus Fusarium (Link, 1809) is considered one of the main causes of globally declining sea turtle populations. In summer 2021, the two northernmost worldwide loggerhead sea turtle nests were monitored along the Northern Adriatic coastline (Veneto, Italy). These first records may potentially candidate this area as suitable for a large part of the loggerhead turtle's life cycle and it could represent a minor sea turtle nesting area that, according to Prato and colleagues, remained unnoticed due to the lack of specific monitoring. Sea Turtle Egg Fusariosis (STEF) was deemed to have deeply compromised the hatching success of the northmost one. Climate change and anthropogenic impacts have been scored as one of the highest hazards to sea turtle health and could have played a role in the STEF development. Environmental changes, human activities, and emerging pathogens deserve the highest attention in terms of health research, and conservation management

Ergatandromorphism in the Ant Myrmica lobulicornis Nylander, 1857 (Formicidae: Myrmicinae)

Ergatandromorphism is the result of an aberrant development in which part of the body of a social insect shows the traits of the worker caste, while the other resembles a male. It is considered a specific case of gynandromorphism. Specimens with these characteristics have rarely been collected in different ant lineages across the world. Here, we provide the first description of ergatandromorphism in the ant Myrmica lobulicornis Nylander, 1857: an ergatandromorphous specimen was recovered during an arthropod sampling campaign across altitudinal and ecological gradients on the Italian Alps (Stelvio National Park), together with 480 workers and 4 queens of the same species, which expressed the normal phenotype

Action A3 : analysis of spatial connectivity and preparation of environmental impact assessment guidelines : prepared within A3 action of LIFE DINALP BEAR Project (LIFE13 NAT/SI/0005)

As for other large carnivores in Europe, the brown bear shows a trend of recovering under different management scenarios. However, this recovery comes with specific biological and conservation requirements at individual and population levels often followed by conflicts in a highly humanized continent. To foresee conflicts with humans and to facilitate decisionmaking, spatially-explicit research is required to identify potential habitats and the connectivity of fragmented bear populations. First, we conducted multiscale modeling based on scale-integrated resource selection functions (SRSFs) to identify drivers shaping the spaceuse of three bear populations/demographic units (Trentino-Swiss, pre-Alps, and Dinaric), and across 3 scales of space (population distribution, home range establishment, and use of individual home range). Secondly, we also conducted an analysis of the connectivity patterns of suitable habitat patches (nodes) to identify the potential importance of each node to contribute to individual mobility, survival, and population connectivity. Lastly, to support further environmental impact assessment analyses, we identified the most plausible least-cost paths connecting different areas of the same large patch with itself and surrounding patches. Using topographic, landcover, and anthropogenic predictors, our analytical approach transcended from scale dependence bias to produce a predictive map on habitat suitability while delivered information on habitat selection trends for each population. Bears mostly selected forest habitats in all the populationshowever, habitat selection differed for the other variables among populations and scales, especially in the Trentino area where the species selected the most intricate topography. Predictive maps revealed a broad range of suitable but fragmented patches of bear habitat. The largest and most important patches for connectivity occurred in the current distribution range of the species, with the most suitable habitat lying in the pre-Alpine and Dinaric populations. Connecting viable patches to host female homeranges is possible through stepping-stone patches of corridors reachable within the estimated dispersal distance of females. Unified transnational decision-making is required for the conservation of stepping-stone patches, facilitate bear mobility, and ultimately connect bear populations.Podobno kot pri drugih vrstah velikih zveri se tudi pri rjavemu medvedu njegovo območje razširjenosti in številčnost povečujeta v več delih Evrope, in to ob različnih upravljavskih pristopih. Vendar uspešno širjenje vrste vselej zahteva specifične biološke in varstvene pogoje na individualni in populacijski ravni. V gosto poseljeni Evropi širjenje medveda pogosto spremljajo tudi konflikti s človekom. Za pravočasno napovedovanje in racionalno preprečevanje konfliktnih situacij s človekom in s tem lajšanja procesa odločanja so ključne zanesljive prostorske raziskave. Te nam omogočajo prepoznavanje potencialnih habitatov za medveda in območij/koridorjev, ki so ključna za ohranjanje povezljivosti populacije. V prvi fazi pričujoče raziskave smo zato izvedli večstopenjsko hierarhično prostorsko eksplicitno napovedno modeliranje habitatne ustreznosti prostora (scale integrated RSF), s katerim smo lahko prepoznali glavne omejitvene dejavnike rabe prostora za tri obravnavane medvedje populacije oz demografske enote (Trentino-Švicarske, pred-Alpska in Dinarska) na treh prostorskih nivojih (populacijski nivo, nivo območja aktivnosti in nivo notranje rabe znotraj območij aktivnosti). Izvedli smo tudi analizo povezljivosti prostora med osnovnimi zaplatami habitata in opredelili prispevek vsake zaplate k %vitalnosti% celotne medvedje populacije v raziskovalnem območju. Končno smo z namenom lažjega prepoznavanja potreb po prihodnjih presojah vplivov posegov na okolje (PVO) opredelili še najbolj verjetne prehode med habitatnimi krpami (least-cost paths). Na osnovi napovednih spremenljivk, ki opisujejo rabo tal, reliefne značilnosti in prisotnost človeka (npr. ceste, naselja) smo pripravili modele habitatne ustreznosti prostora za medveda in prepoznali tudi razlike v habitatnem izboru med 3 obravnavanimi populacijami in prostorskimi merili. V vseh treh populacijah so medvedi primarno izbirali gozdnata območja, so pa med populacijami in prostorskimi merili opazne razlike v rabi/pomenu ostalih okoljskih spremenljivk. Zlasti odstopa skupina medvedov v Trentinu, za katere je značilna izbira bolj nedostopnih območij (težji, topografsko bolj razgiban teren). Naš prostorsko eksplicitni model kaže, da je v obravnavanem območju veliko habitata, ki je primeren za medveda, vendar pa je zanj značilna močna fragmentiranost. Največje in najbolj pomembne zaplate habitata za povezljivost populacije se nahajajo na območju trenutne razširjenosti vrste, z najbolj primernim habitatom na območju pred-Alpske in Dinarske populacije. Zadostno povezanost najprimernejših zaplat (ki so dovolj velike, da v njih lahko žive samice % medvedke), bi bilo mogoče vzdrževati preko ohranjanja dovolj povezanih habitatnih krp v koridorjih (step-stones). Za ohranjanje zadostne povezanosti prostora/habitatov, zagotavljanja povezav med deli populacij in populacijami medvedov ter za dolgoročno viabilnost medveda v območju Alp in Dinaridov je ključna poenotena % med državami usklajena - politika odločanja in rabe prostora

Human‐induced risk drives behavioural decisions in a recovering brown bear population

In human-dominated landscapes, rebounding bear populations share space with people, which may lead to bear–human conflicts and, consequently, a decrease in acceptance and an increase in bear mortality linked to human causes. Previous analyses of brown bear (Ursus arctos) movement data have shown that bears adopt a security-food trade-off strategy in response to variable human-related risk. However, brown bear flexibility to cope with these risky situations may be reduced when resting, mating or stocking fat in preparation for hibernation. In this study, we measured the multi-scale spatial response of brown bears to human-related risk and food resource distribution in a highly heterogeneous human-dominated landscape. We examined habitat selection both within the population range (‘second-order’ selection) and at bedding site locations (‘third-order’) for GPS-tagged brown bears of a recently reintroduced population in the Italian Alps. We identified resting locations by field-validated spatio-temporal cluster analysis of telemetry locations. We mapped food availability and distribution using dynamic geographic layers of fruiting wild berries, and human-related risk using human mobility data (Strava-based Cumulated Outdoor activity Index). Brown bears appeared to compromise their need for food resources for avoidance of anthropogenic disturbance when selecting home ranges, as they utilized areas richer in wild berries less when human use of outdoor tracks was higher. Furthermore, selection of resting site locations strongly depended on the avoidance of human-related risk only, with less frequented, more concealed and inaccessible sites being selected. We conclude that humans compete for space with bears beyond their infrastructural impact, that is, by actively occupying key areas for bear survival, thereby potentially restricting the bears' realized niche. We propose mitigating actions to promote bear–human coexistence by selectively restricting human access to key areas during sensitive annual physiological phases for bear surviva