Carnivore Ecology and Wildlife University of Natural Resources and Management, KORA Life Sciences, Vienna

Movement patterns of Eurasian Lynx (Lynx lynx) in the Northwestern Swiss Alps

Master Thesis for obtaining the academic degree Master of Science in Wildlife Ecology and Wildlife Management

Sven Signer 1341944

Institute of Wildlife Biology and Game Management (IWJ) Department for Integrative Biology and Biodiversity Research

Carnivore Ecology and Wildlife Management, KORA

Supervisors: Univ.Prof. Dipl.-Biol. Dr.rer.nat. Klaus Hackländer Dr. Urs Breitenmoser Dr. Kristina Vogt

Vienna, April 2017

Imprint

Keywords: Movement patterns, Eurasian lynx (Lynx lynx), mating, denning, sex and reproductive status, GPS telemetry

Citation: Signer, S. (2017). Movement patterns of Eurasian lynx (Lynx lynx) in the Northwestern Swiss Alps. Master Thesis. University of Natural Resources and Life Sciences, Vienna (BOKU), Department for Integrative Biology and Biodiversity Research, Institute of Wildlife Biology and Game Management (IWJ), Vienna, Austria.

Institutions University of Natural Resources and Life Sciences, Vienna (BOKU) Department for Integrative Biology and Biodiversity Research Institute of Wildlife Biology and Game Management (IWJ) Gregor-Mendel Strasse 33 A-1180 Vienna

KORA (Carnivore Ecology and Wildlife Management) Thunstrasse 31 CH-3074 Muri

Photo cover page: SILV’s paw, captured on the 31st December 2013 (© Sven Signer).

Declaration in lieu of oath

I herewith declare in lieu of oath that this thesis has been composed by myself without any inadmissible help and without the use of sources other than those given due reference in the text and listed in the list of references. I further declare that all persons and institutions that have directly or indirectly helped me with the preparation of the thesis have been acknowledged and that this thesis has not been submitted, wholly or substantially, as an examination document at any other institution.

Date Signature

Summary

Organismal movement is a fundamental characteristic of life, driven by processes that act across multiple spatial and temporal scales. Therefore, movement plays an important role concerning individual fitness outcomes as well as population dynamics. In this study, I investigated spatio- temporal movement patterns of Eurasian lynx (Lynx lynx) in relation to sex and reproductive status, based on high resolution GPS data. In particular, I focused on the following three topics: 1) seasonal and diurnal movement patterns of females with kittens, females without kittens and males, 2) movement patterns of females with kittens in relation to time of parturition and 3) spatial interactions among male and female lynx. Overall, I analysed GPS data from 22 lynx (10 females, 12 males), resulting in 26’508 lynx positions. Males and females without kittens showed less seasonality than females with kittens. Males showed stationary behaviour mainly during mating, whereas distances covered between stationary phases were longest during this season. The same general pattern with long-distance movement peaks around twilight was observed in males and females without kittens. However, this general pattern was least pronounced in males during the mating season, indicating a strong effect of the mating season on male movement behaviour. Females with kittens showed stronger seasonal variation. During the period of denning they are constrained by the presence of the kittens, and show mostly stationary behaviour. Distance to den site as well as duration away from the den steadily increased with kittens’ age. Already in the 1st week after parturition, the kittens were left alone for more than 6h. In the 7th week after parturition females were away from the den for up to 16h, which corresponds with the time when the females had to go furthest for hunting. With the development of the kittens, long-distance movements steadily increased. Interestingly, females with kittens showed long-distance movements mostly during daylight, when kittens are fully mobile in late autumn and early winter. Around the time of parturition, males visited the females with kittens between 2-6 times. In several cases, the encounters took place in closed proximity to the natal den. This behaviour is most likely a strategy to increase reproductive success, if the first litter is lost. A better understanding of spatial interactions between lynx would improve our knowledge on important parameters determining the demographic status of a population, and in turn, conservation and management of the species.

Zusammenfassung

Bewegungen von Organismen sind ein fundamentales Merkmal von Leben, angetrieben durch Prozesse, die über unterschiedliche räumliche und zeitliche Skalen wirken. Daher spielen Bewegungsmuster eine wichtige Rolle für die individuelle Fitness und Populationsdynamiken. Basierend auf hochaufgelösten GPS-Daten untersuchte ich in dieser Studie räumlich-zeitliche Bewegungsmuster von Eurasischen Luchsen (Lynx lynx) in Bezug auf Geschlecht und Reproduktionsstatus. Insbesondere konzentrierte ich mich auf die folgenden drei Themen: 1) saisonale und tägliche Bewegungsmuster von Weibchen mit Jungen, Weibchen ohne Jungen und Männchen, 2) Bewegungsmuster von Weibchen mit Jungen in Bezug zur Wurfzeit und 3) räumliche Interaktionen zwischen männlichen und weiblichen Luchsen vor und nach dem Wurftermin. Insgesamt analysierte ich GPS-Daten von 22 Luchsen (10 Weibchen, 12 Männchen), was in 26'508 GPS-Positionen resultierte. Im Vergleich zu den Weibchen mit Jungen, zeigten Männchen und Weibchen ohne Junge nur eine geringe Saisonalität. In der Ranzzeit zeigten die Männchen meist stationäres Verhalten, während die zurückgelegte Entfernung zwischen zwei stationären Phasen in dieser Jahreszeit am grössten war. Ein typisches Muster mit Lang-Distanz Bewegungen um die Dämmerungszeit wurde sowohl bei den Männchen als auch bei den Weibchen ohne Junge beobachtet. Dieses allgemeine Muster war bei den Männchen zur Ranzzeit am wenigsten ausgeprägt, was auf einen starken Einfluss der Paarungszeit auf das Bewegungsmuster von Kudern schliessen lässt. Weibchen mit Jungen zeigten die grössten saisonalen Schwankungen. Während der Wurfzeit waren sie durch die Anwesenheit der Neugeborenen eingeschränkt und zeigten meist stationäres Verhalten. Mit zunehmendem Alter der Jungen nahm sowohl die Entfernung zum, als auch die Absenzdauer vom Wurfbau stetig zu. Bereits in der ersten Woche nach der Geburt wurden die Jungen für mehr als 6 Stunden alleine gelassen. In der siebten Woche wurden die Jungen bereits für 16h alleine gelassen, was der Zeit entspricht, wenn die Weibchen die weitesten Jagdausflüge machten. Mit der Entwicklung der Jungen nahm auch der Anteil an Lang-Distanz Bewegungen stetig zu. Im Spätherbst und im frühen Winter, wenn die Jungen mobil sind, zeigten die Weibchen mit Jungen interessanterweise Lang-Distanz Bewegungen vor allem während dem Tag. Um die Wurfzeit besuchten die Männchen die Weibchen zwischen 2-6 mal. In mehreren Fällen fanden die Treffen in unmittelbarer Nähe zum Wurfbau statt. Dieses Verhalten ist wahrscheinlich eine Strategie zur Optimierung des Fortpflanzungserfolges. Die regelmässigen Begegnungen zwischen den Geschlechtern stellen die Möglichkeit von Ersatzwürfen im Falle eines Verlustes sicher. Ein besseres Wissen über räumliche Interaktionen zwischen Luchsen würde unser Verständis über wichtige Parameter, welche einen Einfluss auf die Demografie von Population haben vertiefen, und im Gegenzug den Schutz und das Management der Art verbessern.

Table of Contents

Summary

Zusammenfassung

1 Introduction ...... - 1 -

2 Material and Methods ...... - 6 -

2.1 Study Area ...... - 6 -

2.2 Lynx Captures and Collaring ...... - 8 -

2.3 Data preparation ...... - 9 -

2.4 Statistical analysis ...... - 10 -

3 Results ...... - 12 -

3.1 Seasonal variation in movement behaviour ...... - 12 -

3.2 Seasonal variation in diurnal movement behaviour ...... - 16 -

3.3 Movement patterns of females with kittens in relation to time of parturition ...... - 19 -

3.4 Interactions between male and female lynx ...... - 22 -

4 Discussion ...... - 27 -

5 Conclusion ...... - 33 -

6 Acknowledgements ...... - 34 -

7 Literature ...... - 35 -

Appendices

1 Introduction

Organismal movement is a fundamental characteristic of life, driven by processes that act across multiple spatial and temporal scales (Nathan et al. 2008). It is important for survival and reproduction, because animals move to feed, find mates, avoid predators or adverse environmental conditions (Liedvogel et al. 2013). Therefore, movement plays a major role in determining individual fitness outcomes (Liedvogel et al. 2013) as well as population dynamics (Morales et al. 2010). Movement responses of individuals to changing local conditions affect their individual performance and population level demography, as both spatial and temporal scales increase (Gaillard et al. 2010). Thus, understanding species movement patterns is crucial regarding conservation and management decisions as well as for gaining knowledge on evolutionary processes and behavioural ecology. Owing to its importance for different aspects of animal ecology and conservation, movement behaviour has been addressed by a huge number of studies on a variety of taxa during the last decades (Holyoak et al. 2008). According to Mendez et al. (2014, pp. vii), “this increase in research efforts is partly related to the recent affordability of GPS technology and satellite telemetry, which has revolutionised the study of animal movement, allowing to follow individual animals to remote places at high spatial and temporal resolution.” Earlier studies conducted by means of VHF- technology were very time consuming and the resulting sample size seldom allowed for small scale analysis. Additionally, a lot of manpower was needed and the subsequent locations were often restricted to positions taken during the day, due to visibility constraints during the night. GPS-data are highly precise (spatially and temporally), time-saving and there is no bias due to observer disturbance (Hebblewhite et al. 2010). Instead of analysing single (uncorrelated) locations taken on consecutive days, the high temporal resolution of GPS data allow us to analyse animal trajectories (curve described by the animal when it moves (Calenge et al. 2009)) and different behavioural states. Under the term behavioural states we understand the categorisation of behaviour based on GPS data, where measurable variables (e.g. movement speed) are relatively constant.

Due to the increasing amount of studies concerning animal movement behaviour and the lack of a standardised theoretical approach, Nathan et al. (2008) developed a general framework aimed at unifying organismal movement research. The emerging transdisciplinary paradigm was termed “movement ecology”, and focused on understanding the movement of living organisms in the context of their internal states, traits, constraints, and interactions among themselves and with the environment (Nathan et al. 2008). The framework contains four main components determining an animal’s movement path: Internal states, external factors, navigation capacity and motion capacity. The internal state accounts for physiological and psychological conditions of an individual (e.g. reproductive state, social status) and addresses the question “why move?”, while the external factors represent all aspects of the biotic and abiotic environment influencing movement (e.g. landscape

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features, food availability). The navigation capacity answers the question “when and where to move?” and accounts for the ability of organisms to orient in space and/or time. The last component, the motion capacity, accounts for the ability of individuals to move in various ways or modes (e.g. walking, flying) and, therefore, addresses the question “how to move?” The majority of recent studies have focused on the influence of external factors and motion capacity on movement behaviour (Holyoak et al. 2008). For example, various studies have investigated how habitat features (external factor) shape movement patterns (i.e. Beyer et al. 2016, Panzacchi et al. 2016, Van Moorter et al. 2016) or how animals can optimise their energy expenditure during movement (motion capacity; Dodge et al. 2013). However, much less is known about the effects of navigation capacity or internal state (Holyoak et al. 2008). In this study, I focused on the two latter components and their influence on the movement patterns of a medium-sized carnivore, the Eurasian lynx (Lynx lynx).

Lynx movement

Many studies have investigated the influence of external factors on lynx movement and space use. On the large scale, forest cover (>40%) is a good predictor of lynx occurrence (Niedzialkowska et al. 2006). Home range size is known to be negatively correlated with roe deer (Capreolus capreolus) density (Herfindal et al. 2005), but there is also a trade-off between roe deer abundance and avoidance of human activity (Basille et al. 2009). Nevertheless, lynx may tolerate high human activity (Bouyer et al. 2015a), if enough dense cover is available (Sunde et al. 1998). One study even found that lynx selected the surroundings of tourist trails at night, when human disturbance was low (Belotti et al. 2012). Thus, avoidance of human facilities is assumedly more linked to the presence of people rather than the alteration of the habitat (Sunde et al. 1998).

The pattern of lynx activity (determined by spatial displacement) is shaped predominantly by searching for and consuming large prey (Schmidt 1999). Lynx feed on large prey over several days (Sunde et al. 2000, Molinari-Jobin et al. 2002). During this time movement is very restricted and animals mainly move between resting site and kill site. After giving up a kill, lynx may move long distances to search for new prey (Schmidt 1999). Thus, movement patterns of Eurasian lynx are known to follow a characteristic pattern with altering ‘short-distance’ and ‘long-distance’ movements. Short-distance movements are termed stationary phases in the following. This two movement modes can be summarised under the term ‘behavioural state’. Stationary behaviour is mainly related to movements between resting and kill site, while long-distance movements incorporate exploration of a larger part of the home range.

Besides external influences on movement, differences in space-use among the sexes (internal state) have been extensively studied in lynx research by means of VHF telemetry. Sex-specific space use patterns are likely to emerge, if fitness in one sex is mainly determined by the investment into offspring (females) and by mating opportunities in the other sex (males) (Clutton-Brock & Harvey

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1978). Therefore, this should clearly be the case for the Eurasian lynx, as only females have high costs of raising the kittens whereas males only search and mate guard females during the mating season (Breitenmoser & Breitenmoser-Würsten 2008). Indeed, different studies have revealed sex- specific space use patterns: Male lynx are known to maintain larger home ranges and move longer distances per day than females (Sunde et al. 2000, Breitenmoser & Breitenmoser-Würsten 2008). This difference is caused by the lynx’ land tenure system, where males overlap with the home range of several females and try to monopolise them during the mating season. In a comprehensive study on lynx movement patterns, Jedrzejewski et al. (2002) found that daily movement distances are increased during the mating season in males (+56%), while females increased movement (+43%) during the period of intensive care for kittens. Male home range size is increased just before and during mating (Schmidt et al. 1997), while female home range size is reduced during the period of denning (Kaczensky 1991, Schmidt et al. 1997). The contrary pattern of increased movement (Jedrzejewski et al. 2002), but reduced home range size (Kaczensky 1991, Schmidt et al. 1997) of females during denning, might be explained by the concentrated nature of females’ movement, as they moved intensively but stayed close to the previous day’s location (Jedrzejewski et al. 2002). This is likely caused by movements in several directions to and from the den site, resulting in a star shaped movement pattern (Van Dalum 2013). Furthermore, avoidance of human activity is greater for females with newborn kittens than for males (Bunnefeld et al. 2006). After parturition, females are constrained by the presence of kittens. Their movement was restricted to about 3 km around the den site for the first two months after parturition, while in August kittens started to accompany their mother (Schmidt 1998). Kaczensky (1991) found females with kittens only using 4-8% of the total home range during denning.

Besides the VHF-telemetry studies mentioned above, GPS technology has been applied in lynx research since recent years. GPS studies related to movement of the Eurasian lynx have so far mainly focused on external factors, e.g. habitat selection during different behavioural states (Bouyer et al. 2015b, Gehr 2016), factors affecting home range sizes (Aronsson et al. 2016) and the influence of human disturbances on lynx distribution (Belotti et al. 2012). These studies have profited from the high precision and resolution of GPS locations and the reduced bias toward day locations. Thus, some recent GPS studies have provided novel insights into lynx ecology. For example, contrary to the findings of Schmidt et al. (1997), Aronsson et al. (2016) reported reduced home range sizes for males during the mating season. They hypothesised that these findings were likely caused by the fact that males remained close to individual females in estrous. Furthermore, they pointed out, that male home range size was mainly determined by conspecific density and the distribution of females, while female home range size was highly influenced by prey density.

None of the GPS studies mentioned above have aimed at analysing differences in small scale movement patterns related to internal state (sex and reproductive status) and navigation capacity

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(diurnal and seasonal rhythms in movement behaviour) at the same time. In this study, I aimed to fill this gap by focusing on diurnal and seasonal movement patterns related to sex and reproductive state of the Eurasian lynx, taking advantage of high resolution day and night locations provided by GPS technology.

Aims of the study

The main objective of the study was to characterise spatio-temporal movement patterns of Eurasian lynx in relation to sex and reproductive state. In more detail, my goal was to answer the following research questions:

1) How is variation in lynx movement (proportion of stationary phases and long-distance movements & distance between stationary phases) related to season, sex and reproductive state of the lynx?

Hypothesis 1.1: Seasonal differences in the proportion of the two behavioural states (stationary vs. long-distance) are related to sex and reproductive state of the lynx.

Prediction 1.1.1: Males show the highest proportion of long-distance movements. Females with kittens have higher proportion of stationary phases compared to females without kittens and males.

Prediction 1.1.2: During the mating season, male lynx show most long-distance movements.

Prediction 1.1.3: Female lynx with kittens show stronger seasonal variation in movement behaviour than females without kittens.

Hypothesis 1.2: Seasonal differences in distances between stationary phases are related to sex and reproductive state of the lynx.

Prediction 1.2.1: Males move longest distances between stationary phases during the mating season. They move longer distances than females with and without kittens.

Prediction 1.2.2: Female lynx without kittens move longer distances between stationary phases compared to females with kittens in all seasons.

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2) Is the observed seasonal variation in the proportion of the two behavioural states (H1.1) caused by the movement behaviour of lynx during the day or during the night?

Hypothesis 2.1: There are seasonal differences in diurnal movement behaviour related to sex and reproductive state of the animal.

Prediction 2.1.1: Males move long distances during twilight and night. During the mating season, long-distance movements also occur during daylight.

Prediction 2.1.2: During denning, females with kittens show stationary behaviour during the day and during the night. As the kittens grow older, females with kittens show more long-distance movements during twilight and night (like males and females without kittens).

Prediction 2.1.3: Females without kittens move long-distances during twilight and night.

Furthermore, I aimed to gain a deeper insight into crucial periods of the lynx’ life cycle. Concerning the fitness of female lynx, I describe movement patterns during the most important period (i.e. denning). Denning behaviour of female lynx has been studied by means of VHF telemetry (Kaczensky 1991, Schmidt 1998, Reinhardt & Halle 1999), observations in an enclosure (Chageava & Naidenko 2012) and GPS telemetry (Krofel et al. 2013, Van Dalum 2013). A common problem in analysing denning behaviour with GPS data is the high amount of missing locations, which arises when females are using strongly sheltered den sites (Krofel et al. 2013). Because I have additional information on den use gained by means of VHF telemetry and ground truthing of GPS location clusters, I can fill this gap. I aimed to characterise fine scale movements of reproductive females from the birth of their kittens to the end of summer in order to supplement the knowledge gained from a small sample size of female lynx during an early study by Kaczensky (1991). I am especially interested in how far and how long the females moved from their den in relation to the development of the kittens. Furthermore, I wanted to know more about how movement patterns of females are influenced during the time when kittens are no longer at the den but not yet fully mobile. The last objective of my study was to investigate the interactions among neighbouring lynx’ of different sexes during the period before and while denning. Wölfl (1993) investigated spatial competition avoidance between male and female lynx in Switzerland based on VHF-telemetry. In this study, I wanted to supplement these findings based on a high resolution time series.

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2 Material and Methods

2.1 Study Area

The study was conducted mainly in the Bernese Oberland (Fig.2), a mountainous area in the Northwestern Swiss Alps (Fig.1) in the Canton of Bern. Some individual lynx home ranges also included parts of the pre-Alps of the Cantons of Vaud (LOKI), Fribourg (RIKA, MARI and PIRO) and Lucerne and Obwalden (AMOR). About 30% of the area is covered in forest. The main tree species is spruce (Picea abies, 49%), followed by silver fir (Abies alba, 23%), beech (Fagus sylvatica, 18%), sycamore (Acer pseudoplatanus, 2%) and ash (Fraxinus excelsior, 2%) (Amt für Wald, 2010). Altitudes range from 800m to 2500m above sea level. The main prey species for lynx in the Northwestern Swiss Alps are roe deer and Alpine chamois (Rupicapra rupicapra) (Molinari-Jobin et al. 2007). In winter 2013/2014 lynx density was estimated to be 2.05 (1.50-2.60, 95% confidence interval) independent (subadult and adult) lynx/100 km2 of suitable habitat (Zimmermann et al. 2014) and 2.13 (1.73-2.53, 95% confidence interval) independent lynx/100 km2 of suitable habitat in winter 2011/2012 (Zimmermann et al. 2012). The Bernese Oberland harbours the most important lynx population within the whole Alps and lynx biology has been studied for more than 30 years in this area (Breitenmoser & Breitenmoser-Würsten 2008).

Fig. 1: Location of the study site in Switzerland. The red area indicates the 95% Minimum Convex Polygon of all individuals of the southern and northern part of the population, calculated with the R-package “adehabitat” (Calenge 2006).

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2.2 Lynx Captures and Collaring

Data were gathered as part of a research project (NWA III) about lynx demography, genetics and predation in the Northwestern Swiss Alps (project by KORA; Carnivore Ecology & Wildlife Management, www.kora.ch). Lynx were captured either with foot-snares set at fresh kills, unbaited walk-through box-traps or a remote teleinjection-system developed by Ryser et al. (2005). A detailed description of the capture protocol is given in Vogt et al. (2016). Lynx were immobilised applying intramuscular injection of 0.1-0.15 mg/kg medetomidine hydrochloride (Domitor, Orion Corporation, Espoo, Finland) and 3.2-5.5 mg/kg ketamine hydrochloride (Ketasol, Graeub, Switzerland). 0.56- 0.77 mg/kg atipamezole hydrochloride (Antisedan, Orion Corporation, Espoo, Finland) was used as an antagonist. Lynx were equipped with GPS/GSM-collars (Lotek wireless, Ontario, Canada) and tracked for periods ranging from 1.5 to 23 months. Overall, we obtained data on 22 lynx (10 females, 12 males; Fig.3), resulting in 26’508 lynx positions.

Fig. 3: Sample size overview. Overall, we have data from 22 lynx, resulting in 26’508 location records. The sample includes 12 males (black bars; 15’269 locations) and 10 females (grey bars; 11’239 locations). Light grey bars indicate females without kittens, whereas dark grey bars represent females with kittens. EYWA and GIRO were captured two times.

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2.3 Data preparation

Explorative analysis of our data showed an increasing amount of missing values when females became stationary to give birth. This pattern is most likely caused by restricted satellite connection due to the use of natal dens, which are often located beneath rocks, tree roots or in crevices (Boutros et al. 2007). Alfredéen (2006) found the frequency of received positions to be a suitable method for identifying time of reproduction in wolves. Because lynx kittens of collared females were sampled and tagged with subcutaneous chips 4 weeks after birth as part of a research project on demography and genetics, we have detailed information on the exact location of natal dens as well as on the use of secondary den sites gathered by means of VHF-telemetry and ground truthing of GPS location clusters. Thus, we were able to interpolate missing locations with the coordinates of the respective den site during a certain time period (Appendix A). Interpolation of data points was only conducted during the time period when locations of natal and secondary den sites could be inferred from field observations. Although missing values can have different reasons, we assumed missing locations to be mainly caused by den use during this period. If a female was accompanied by kittens in a given year, she was considered as with kittens from the date of conception (= estimated parturition date – 72 days (gestation period)) in order to account for changes in behaviour already during pregnancy. Star shaped movement pattern (Van Dalum 2013), missing locations and stationary behaviour served as indication of being accompanied by kittens.

In order to answer different research questions within the project, collars were programmed to take locations at varying time intervals, ranging from 5 minutes to 12 hours, with the majority of fix intervals between 1 and 3 hours. The fix rate is a crucial parameter in movement analysis, because it determines the scale of the analysis. In order to standardise our sample, only fix intervals ranging from 1 to 4 hours were considered. Furthermore, a burst (sequence of GPS fixes) was constrained to include at least four consecutive points. Subsequently, movement speed was calculated based on straight line distances and time interval between consecutive GPS locations for each individual. Although I eliminated the most extreme fix intervals, locomotion speed was still dependent on fix interval. Speed decreased with increasing fix interval. To overcome this bias, I classified each position into two behavioural states (stationary phases/long-distance movements) using a broken- stick model based on locomotion speed (Sibly et al. 1990, Johnson et al. 2002, Gehr 2016). Data from the male FAUN in December 2013 were removed, because it severly affected model outcomes. During this time, FAUN was extremly stationary due to health problems.

Broken-Stick Model

Several statistical models are available in movement analysis, in order to assign movement patterns to different behaviours (e.g. State Space Models, Markov Chain Monte Carlo Models). However, most models assume regular time intervals between locations and require very high localisation

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rhythms, and our data was not suitable for applying one of these approaches. Thus, we applied a broken-stick model according to Sibly et al. (1990), Johnson et al. (2002) and Gehr (2016). Each GPS-location was classified as belonging to either a stationary phase or long-distance movement, based on locomotion speed. This classification corresponds well to the typical movement pattern of lynx with stationary phases, during which the animal remains in the vicinity of a fresh kill for up to several days, and phases of increased movement, when the lynx uses larger parts of its home range, presumably to search for prey in new areas (Breitenmoser & Breitenmoser-Würsten 2008, Vogt et al. 2016). The optimal speed threshold for separating the two behavioural states was calculated as explained in Gehr (2016). Because proportion of classification was still dependent on fix interval (1- 2h & 3-4h), I had to apply two separate models for fix intervals of a) 1-2h and b) 3-4h. After this procedure, grouping (into stationary and long-distance) was independent from fix interval. A more detailed description is given in Appendix B.

2.4 Statistical analysis

In order to investigate the effect of sex and reproductive state on seasonal and diurnal variations in movement behaviour, we applied Generalised Additive Mixed Models (GAMMs) with binomial error distributions fitted by maximum likelihood, using the R package ‘gamm4’ (Wood & Scheipl 2014). ‘gamm4’ is numerically more robust than “gamm” (Wood & Scheipl 2014) and gives better performance for binary data (Wood & Scheipl 2014). GAMMs are an ideal tool for analysing non- linear relationships and circular variables such as Julian day or time of the day. Behavioural state (stationary, long-distance movement) was entered as dependent variable, while Julian day and time of the day (both continuous) were considered as fixed effects. To avoid pseudoreplication and account for individual variation, animal identity was entered as a random factor in all analyses. Because of the reduced flexibility in modelling interactions within GAMMs, three identical models were run, one for each sex and reproductive state (males, females with kittens and females without kittens). Differences were considered significant, if 95% confidence intervals of the model predictions did not overlap.

Furthermore, distance between stationary phases was also analysed using the GAMM approach described above. However, model performance was very poor (Appendix C) and variable transformation did not improve the model fit. Thus, I applied a Linear Mixed Model using R-package “lme4” (Bates et al. 2015). Models were fitted using REML with a gaussian error distribution. To achieve normal distribution of the model residuals, the distance covered between stationary phases was raised to the power of 0.2. Distance between stationary phases was considered as dependent variable, while season, sex and reproductive status (males, females with kittens and females without kittens) and their two-way interactions were considered as fixed effects. Tukey post-hoc test within R-package “lsmeans” (Lenth 2016) was used to test seasonal differences between reproductive

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states. Seasons were defined as follows: pre-mating (15.Dec-14.Feb), mating (15.Feb-14.Apr), pregnancy (15.Apr-14.Jun), denning (15.Jun-14.Aug), small cubs (15.Aug-14.Oct) and big cubs (15.Oct-14.Dec) (Vogt et al. 2014). Again, animal identity was entered as a random effect in all models. Model assumptions were checked graphically and confirmed (Appendix D).

In order to visualise movement patterns of females with kittens I calculated trajectory lengths (sum of distances between all consecutive locations) for each individual for each week. Afterwards, mean distances +/- standard error (SE) covered per week before/after birth were calculated. This step was justified as all females had the same localisation rhythm within this period. Furthermore, maximum distances away from the den/week after parturition were determined for each female. Subsequently, mean maximum distances +/- SE away from the den/week after birth were calculated. In order to show how long females were absent from the den, the duration of each trip away was calculated. Females were considered away if distance to the den site was >100m. As explained above, mean maximum durations away from the den were calculated. To describe spatio-temporal interactions among the two sexes, I calculated distances between two individuals, who occupied the same area at the same time. This was possible for five lynx pairs for a period of four weeks before to eight weeks after parturition of the females. A potential encounter was defined as follows: two individuals were located at the same time <1km from each other. All analyses have been conducted using program R version 3.2.3 (R Development Core Team, 2015).

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3 Results

The classification into stationary and long-distance movements differed significantly among the different sexes and reproductive states (χ2=381.37, df=2, p<0.05) (Table 1). Males have a higher proportion of long-distance movements compared to the two reproductive states of the females. Females with kittens showed the highest amount of stationary movements. Females without kittens showed proportions between the other two lynx categories.

Table 1: Classification into stationary and long-distance movements according to sex and reproductive state of the lynx, based on the broken-stick-model (Appendix B).

Reproductive state

Behavioural state male female with kittens female without kittens

Stationary 41% 56% 48%

long-distance 59% 44% 52%

3.1 Seasonal variation in movement behaviour

Movement behaviour of females with kittens showed the highest seasonal variation, while there was comparably less seasonality in the movement behaviour of females without kittens and males (Fig.4). Females with kittens showed the lowest amount of long-distance movements during the period of denning and when they had small cubs. Males were more stationary in late fall and early winter (big cub and pre-mating season) compared to the denning season. Their long-distance movements started to increase during the mating season and reached a peak in summer (during the denning period). The strongest difference between males and solitary females was found in early winter (big cubs and pre-mating season), with males showing more stationary behaviour. Females with kittens showed significantly different patterns compared to males and females without kittens. After the extensive stationary phase during denning and small cub season, they showed a steady increase in long-distance movements.

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Fig. 4: Seasonal variation in movement behaviour between lynx of different sex and reproductive status. Solid lines show predicted values from the GAMM for the proportion of locations classified into stationary vs. long- distance movements per Julian day. Dashed lines indicate 95% confidence bands. The means of the predicted values are centered around zero for each reproductive state (relative comparison). Values above zero indicate more long-distance movements.

The distances covered between two consecutive stationary phases ranged from 67m to 48’990m with an average of 3’854m (Fig.5). Distances between stationary phases varied among the different seasons, sexes and reproductive states (Table 3). There was a trend that the interaction between season and reproductive state (females with kittens, females without kittens and males) of the lynx affected all distances between the two consecutive stationary phases. Apart from that, both main effects had highly significant effects on the depending variable (Table 2). Male lynx covered longer distances between stationary phases than females with and without kittens during the mating and pregnancy period (Table 3). Interestingly, in any of the seasons distances covered between stationary phases did not differ between females with and without kittens (Table 3). There was no difference between males and females during period of denning (Table 3). Afterwards, in the small- cub season, females with kittens move significantly shorter distances compared to males (Table 3).

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Table 2: ANOVA table from the fitted linear mixed model. The term status includes the factor levels males, females with kittens and females without kittens. The factor season includes the levels pre-mating, mating, pregnancy, denning, small cubs and big cubs. numDF=numerator degrees of freedom, denDF=denominator degrees of freedom.

numDF denDF F-value p-value (Intercept) 1 3825 8739.917 <.0001 season 5 3825 4.003 0.0013 status 2 3825 6.389 0.0017 season:status 10 3825 1.661 0.0839

Fig. 5: Mean distances covered between stationary phases (in meters) +/- SE for the different sexes and reproductive states in relation to the season.

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Table 3: Seasonal contrasts in distances covered between stationary phases among different reproductive lynx states from the Linear Mixed Model. Tukey post-hoc test within R-package “lsmeans” (Lenth 2016) was applied to produce seasonal contrasts. SE=standard error, df=degrees of freedom. Pre-Mating: contrast estimate SE df t.ratio p.value female_with - female_without -0.35743284 0.4892188 3827 -0.731 0.7453 female_with - male -0.58701420 0.4887448 20 -1.201 0.4662 female_without - male -0.22958136 0.1648116 20 -1.393 0.3633 Mating: contrast estimate SE df t.ratio p.value female_with - female_without 0.01248407 0.1391344 3827 0.090 0.9956 female_with - male -0.40677808 0.1391344 20 -2.924 0.0219 female_without - male -0.41926215 0.1494919 20 -2.805 0.0282 Pregnancy: contrast estimate SE df t.ratio p.value female_with - female_without 0.10698039 0.1780209 3827 0.601 0.8196 female_with - male -0.45474858 0.1314049 20 -3.461 0.0067 female_without - male -0.56172897 0.1870559 20 -3.003 0.0184 Denning: contrast estimate SE df t.ratio p.value female_with - female_without 0.07685506 0.1775001 3827 0.433 0.9018 female_with - male -0.11201482 0.1324861 20 -0.845 0.6798 female_without - male -0.18886987 0.1890190 20 -0.999 0.5858 Small Cubs: contrast estimate SE df t.ratio p.value female_with - female_without -0.18326995 0.1788942 3827 -1.024 0.5614 female_with - male -0.55648669 0.1454590 20 -3.826 0.0029 female_without - male -0.37321674 0.1876079 20 -1.989 0.1408 Big Cubs: contrast estimate SE df t.ratio p.value female_with - female_without -0.34808214 0.2503397 3827 -1.390 0.3460 female_with - male -0.37094696 0.1707588 20 -2.172 0.1007 female_without - male -0.02286482 0.2412650 20 -0.095 0.9951

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3.2 Seasonal variation in diurnal movement behaviour

Male lynx exhibited a pattern with two peaks of long-distance movement behaviour at dawn and dusk and mostly stationary behaviour around midday throughout all seasons (Fig.6). This pattern was most pronounced during the ‘small cub’ season (15.August-14.October). Movement behaviour showed lowest variation during the mating season. During this time, male movement behaviour was only little influenced by time of the day.

Fig. 6: Seasonal variation in diurnal movement patterns of male lynx. Solid lines show predicted values from the GAMM for the proportion of locations classified into stationary vs. long-distance movements per Time of the Day. Dashed lines indicate 95% confidence bands. The means of the predicted values are centered around zero for each season (relative comparison). Values above zero indicate more long-distance movements. Vertical lines indicate civil sunrise and civil sunset, calculated with R-package “maptools” (Bivand & Levin-Koh, 2016). n denotes the number of observed individuals.

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Diurnal movement patterns of females with kittens showed high seasonal variation (Fig.7). During the mating season, a pattern with two movement peaks at dawn and dusk could be observed. During pre-mating, pregnancy and denning almost no variation was observed. During the seasons ‘small cubs, and big cubs’, female lynx with kittens increased long-distance movements during daylight hours, while stationary behaviour was more likely to occur at night. In order to test for the robustness of the approach to interpolate missing locations with the coordinates of the den site, I also conducted this analysis with the raw data. Analysis of data without interpolated den sites yielded similar results (as in Fig.7).

Fig. 7: Seasonal variation in diurnal movement behaviour of female lynx with kittens. Solid lines show predicted values from the GAMM for the proportion of locations classified into stationary phases vs. long- distance movements per Time of the Day. Dashed lines indicate 95% confidence bands. The means of the predicted values are centered around zero for each season (relative comparison). Values above zero indicate more long-distance movements. Vertical lines indicate civil sunrise and civil sunset, calculated with R- package “maptools” (Bivand & Levin-Koh, 2016). n denotes the number of observed individuals.

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Females without kittens displayed a pattern with more long-distance movements around twilight and stationary phases mainly during daylight hours (Fig.8). For the seasons not mentioned in the graphic, sample size was too low for model calculation.

Fig. 8: Seasonal variation in diurnal movement behaviour of females without kittens. Solid lines show predicted values from the GAMM for the proportion of locations classified into stationary phases vs. long-distance movements per Time of the Day. Dashed lines indicate 95% confidence bands. The means of the predicted values are centered around zero for each season (relative comparison). Values above zero indicate more long-distance movements. Vertical lines indicate civil sunrise and civil sunset, calculated with R-package “maptools” (Bivand & Levin-Koh, 2016). n denotes the number of observed individuals.

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3.3 Movement patterns of females with kittens in relation to time of parturition

The eight females considered in the following analysis gave birth within a short period between 16th May and 3rd June. There was high variation in mean distances covered per week before and after giving birth (Fig.9). Overall, distances covered per week averaged 12km +/-0.57 (SE). There was a distinct decrease in distances covered towards time of parturition (red line), during which the females only covered 6km/week on average. Already six weeks before giving birth, the distances covered steadily decreased. After giving birth, distances increased until week six, followed by a decrease until week 10 after birth. Afterwards, distances increased but with a high amount of variation.

Fig. 9: Mean distances (+/- SE) covered by females with kittens in relation to weeks before/after parturition. The sample includes data from the females CARA, EYWA, ISIS, KANA, LELA, MARI, NEVE and SUNA.

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For the following part, data from the females CARA, EYWA, ISIS, LELA, MARI, NEVE and SUNA were available. KANA was excluded because of lack of knowledge on den use and GPS collar failure. The females used one natal den site and 2-4 secondary den sites. Den site occupancy was observed until nine weeks after parturition. Afterwards, females with kittens did not return to a secondary den site, but stationary phases corresponded to kill sites and resting sites. Mean maximum distances from the den sites ranged from 1.56km +/- 0.31 (SE) in the 1st week to 2.71km +/- 0.58 (SE) in the 6th week after parturition (Fig.10). Within the first weeks, distances from the den constantly increased. The largest distance away from the den site was 5.9km, recorded in the 5th week after parturition.

Fig. 10: Mean maximum distance (in km) away from the den site in relation to weeks after parturition. Only weeks with data from all females (n=7) are considered. Black dots show mean values, error bars show standard errors.

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Mean maximum duration away from the den site ranged from 6.5h +/- 1.5 in the 1st week to- 16.7h +/- 4.56 in the 7th week after parturition (Fig.11). The duration of females’ absence from the den site increased up to week seven. There is a 2.5 fold increase in duration away from the den from week one to week seven. Over all weeks, females were absent from the den for 6.19h +/- 0.32 (SE) per trip on average.

Fig. 11: Maximum duration away from the den in relation to weeks after parturition. Distances >100m appart from the den were considered as away from the den. Only weeks with data from all females (n=7) are considered. Black dots show mean values, error bars show standard errors.

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3.4 Interactions between male and female lynx

Mean distance between ISIS and LARY averaged 8.54km between May and August. The two individuals were nearer than 1km only twice (Fig.12). The first encounter took place on the 10th of June (11 days after parturition). They approached each other to a distance of 0.13km. The second encounter (0.94km) between the two individuals was recorded during the night of 20th/21st of July and corresponds to a visit of LARY close to a secondary den site of ISIS (52 days after parturition).

Fig. 12: Spatial interaction of male LARY and female ISIS. Time series plot of the distance (km) between the two individuals. LARY is the father of ISIS’ kittens. Mean distance averaged 8.54 km. The grey dotted line indicates the parturition date (30th of May 2014). The red solid line indicates a distance of 1km.

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The mean distance between SUNA and GIRO was 7.59km. Overall, four potential encounters between the two individuals were observed (Fig.13). The first meeting dated on 23rd April (25 days before parturition, 0.42km). The second potential meeting took place on the 4th / 5th of May (14 days before giving birth, 0.03km). The third meeting (0.61km) took place only 20hours before parturition. The last encounter (0.64km) occurred 49 days after parturition (6th of July) in the proximity of a secondary den site.

Fig. 13: Spatial interaction of male GIRO and female SUNA. Time series plot of the distance (km) between the two individuals. GIRO is the father of SUNA’s kittens. Mean distance averaged 7.59 km. The grey dotted line indicates the parturiton date (18th of May 2013). The red solid line indicates a distance of 1km.

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On average, MARI and PIRO were 6.92km apart from each other. Overall, six possible meetings were observed. The first potential encounter dated on the 7th of June (6 days after parturition, 0.93km, Fig.14). During the period of denning, PIRO visited the natal den of MARI on the 18th/19th (17 days after birth) and 23th of June (22 days after parturition) and was again close to the den area on the 6th (36d), the 20th (50d) and the 23rd (53d) of July. Contrary to the other lynx pairs, PIRO is not the father of MARI’s kittens.

Fig. 14: Spatial interaction of male PIRO and female MARI. Time series plot of the distance (km) between the two individuals. PIRO is not the father of MARI’s kittens, but he is related to her. Mean distance averaged 6.92 km. The grey dotted line indicates the parturition date (1st of June 2011). The red solid line indicates a distance of 1km.

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The distance between CARA and AMOR averaged 8.31km. Overall, three potential encounters were observed (Fig.15). They were first close to each other on the 19th of May (14 days before parturition, 0.88km). The second approach took place 20 days after giving birth (23rd of June, 0.03km). The last encounter occured 37 days after parturition (10th of July, 0.61km).

Fig. 15: Spatial interaction of male AMOR and female CARA. Time series plot of the distance (km) between the two individuals. AMOR is the father of CARA’s kittens. Mean distance averaged 8.31 km. The grey dotted line indicates the parturition date (3rd of June 2016). The red solid line indicates a distance of 1km.

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NEVE and LUPO showed the shortest mean distance between each other (3.28km) out of all lynx pairs. Overall, six potential encounters were observed (Fig.16). The first potential encounter registered on the 2nd/3rd of May (21 days before birth, 0.12km). 7 days before parturiton (17th of May), the second potential meeting was observed. A very long encounter (5th-8th of June) was 12 days after parturition, when LUPO had a kill near the den site. The 4th and 5th meeting occurred 30 (0.73km, 22nd of June) and 42 days after giving birth (4th of July). The shortest distance between the two individuals was recorded 51 days after parturition (0.01km, 13th of July) and corresponds to a visit of LUPO at the den site.

Fig. 16: Spatial interaction of male LUPO and female NEVE. Time series plot of the distance (km) between the two individuals. LUPO is the father of NEVE’s kittens. Mean distance averaged 3.28 km. The grey dotted line indicates the parturition date (23rd of May 2016). The red solid line indicates a distance of 1km.

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4 Discussion

In this study, I investigated spatio-temporal movement patterns of Eurasian lynx in relation to sex and reproductive status, based on high resolution GPS data. The first objective of the study was to characterise seasonal and diurnal movement patterns of females with kittens, females without kittens and males. Furthermore, I aimed at describing movement behaviours of females with kittens in relation to time of parturition, as this period is important concerning recruitment and reproductive success of the species. In the last part, I focused on spatial interactions among neighbouring male and female lynx. Movement patterns of Eurasian lynx are known to follow a characteristic pattern with alternating ‘long-distance’ movements and stationary phases. Stationary phases are mainly related to resting, feeding and denning behaviour, while long-distance movements represent exploration of the home range.

As predicted, females with kittens showed the highest amount of stationary phases, males the highest amount of long-distance movements, whereas females without kittens were in between

(P.1.1.1). Overall, males had a higher proportion of long-distance movements compared to females with and without kittens (Table 1). In addition, males moved further between stationary phases compared to females with and without kittens (as predicted P.1.2.1). This result fits the fact, that male lynx are known to maintain larger home ranges compared to females (Breitenmoser & Breitenmoser- Würsten 2008). Thus, males have to allocate more time to patrolling their home ranges in order to maintain and defend exclusive territories. Females with kittens had the highest amount of stationary phases. Obviously, this is caused by the mostly stationary behaviour after giving birth, when they only moved short distances between den and kill sites. Furthermore, females with kittens are expected to be more stationary, as family groups are known to have a higher kill rates compared to solitary males and females (Molinari-Jobin et al. 2002, Belotti et al. 2015).

Seasonal variation in movement behaviour

Focusing on seasonal patterns, females without kittens and males showed less variation in movement behaviour compared to females with kittens (Fig.4). Contrary to my prediction, male lynx did not increase long-distance movements during the mating season (P.1.1.2). While mating, males were more likely to show stationary behaviour compared to summer. This is surprising, because I expected male lynx to increase long-distance movements during the mating season in order to increase reproductive success. Similarly to my results, Aronsson et al. (2016) reported reduced home range size for male lynx during the mating season in Norway and Sweden. But the situation is different, as Eurasian lynx maintain much larger home ranges in Scandinavia compared to the Alps (Breitenmoser & Breitenmoser-Würsten 2008). Nevertheless, a reasonable explanation is the fact, that males mate guard the females and stay in their proximitiy for several days (Breitenmoser & Breitenmoser-Würsten 2008). Because females have an induced ovulation, males have to invest

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time into females in estrous in order to ensure paternity and increase fitness. Additionally, lynx feed more on large prey in winter compared to summer (K. Vogt, unpublished data), which results in elongated stationary phases. Contrary to the increased amount of stationary movement behaviour, distances covered between stationary phases were highest during the mating season in male lynx

(P1.2.1). That is, they spent more time stationary but when they did move, they covered much larger distances compared to other seasons. Similar to my results, Jedrzejewski et al. (2002) reported a 56% increase in daily movement distance of male lynx during the mating season compared to the rest of the year. This may suggest, that males tend to increase reproductive success by increasing the chance to meet more than one female in estrous. Furthermore, males have to patrol their territory in order to outcompete possible competitors. In addition, male lynx covered significantly longer distances between stationary phases than females with and without kittens during the period of pregnancy. Females with kittens show mainly stationary behaviour during the denning period and increase long-distance movements as kittens grow older. Based on a small sample size conducted by means of VHF-technology, already Kaczensky (1991) reported reduced space use for females after giving birth. She found out, that the two females with kittens she observed only used about 4- 8% of their total home range after parturition. Reduced female home range size after parturition has also been reported for lynx in Scandinavia (Aronsson et al. 2016). After giving birth, females are constrained by the presence of immobile kittens. The movement pattern during denning is characterised by very concentrated displacements around the den, resulting mainly from movements between den and kill sites. With increasing age, the offspring becomes more mobile and long- distance movements steadily increase. As predicted, females without kittens only showed little seasonality compared to females with kittens (P.1.1.3). On the contrary, distances covered between two stationary phases did not differ between the two reproductive states of females and the prediction that females without kittens cover longer distances than females with kittens in all seasons

(P.1.2.2) had to be rejected. This shows that the movement of females with kittens after parturition has to be very concentrated, as they were more likely stationary than females without kittens but, distances covered between stationary phases equal.

Seasonal variation in diurnal movement behaviour

Compared to seasonal changes in movement behaviour, diurnal variation was much higher (Fig.6- 8). As predicted, males and females without kittens showed a typical pattern with peaks of long- distance movements around twilight, and a higher proportion of long-distance movements during the night than during the day (P.2.1.1/P.2.1.3). This general pattern of activity is known to occur over a wide latitudinal range (Heurich et al. 2014). Eurasian lynx are known to synchronise their activity with that of the main prey (Schmidt 1999, Podolski et al. 2013). The main prey species in our study area is roe deer and Alpine chamois (Molinari-Jobin et al. 2007). Both species are known to be mainly crepuscular (roe deer Stache et al. 2013, chamois Mason et al. 2014). Thus, lynx may try to increase

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the chance to encounter potential prey by moving long distances mainly around twilight, when their main prey is expected to be most active. The clear pattern of movement peaks around twilight is less pronounced during the mating season in male lynx, indicating a strong effect of the mating season on male movement behaviour. The prediction that males typically move long distances during twilight and night, but also during the day while mating (P.2.1.1), is supported by my results. A very different movement behaviour was found in females with kittens. The well-known pattern with more long- distance movements during twilight was distinct only during the mating season. During pregnancy and denning, no clear diurnal pattern was recognisable and the prediction that they show stationary behaviour during the day as well as during the night while denning (P.2.1.2) was supported. Already Schmidt (1999) stated, that active locations (determined by spatial displacement) of female lynx in Bialowieza are more evenly distributed over the day and night compared to males. Similarly, a female lynx with kittens, tracked by Reinhardt & Halle (1999) was active as long during the daylight as during the night. Furthermore, a study conducted on Canada lynx (Lynx canadensis) showed, that proportion of time spent active (also determined by spatial displacement) of females with kittens is the same at dusk, dawn, day and night during the periode of denning (Olson et al. 2011). The similar results in my study further support the pattern observed in earlier studies. When the kittens are born, the females are no longer able to maintain the general activity pattern (with movement peaks at twilight), which is entrained to that of their main prey. Interestingly, studies conducted in Canada showed, that during the denning period females with kittens started to hunt ground squirrels (Spermophilus sp.), which are diurnal (Kolbe & Squires 2007, Olson et al. 2011). Lynx in our study area are known to show seasonality in prey preferences to some extent. For instance, lynx show a high preference for chamois kids in early summer (Vimercati 2014). But up to now, there is no evidence of differences in the prey spectrum between males and females with kittens in the denning season (Vimercati 2014). During the small and big cub seasons, when the kittens become more mobile, females with kittens are even more likely to show long-distance movements during the daylight hours than during the night. A completely reversed pattern compared to the expected behaviour with movement peaks around twilight and during night (P.2.1.2). Many mammalian species are known to exhibit diurnal activity as juveniles and switch to nocturnality as adults. For instance, this behaviour is known to occur in red fox (Vulpes vulpes, Zeiler 2016) and Iberian lynx (Lynx pardinus, Beltran & Delibes 1994). Observations at a red fox den site showed increased daylight activity during the period of rearing the pups (Zeiler 2016). If the activity pattern of the juveniles is decisive for the activity pattern of adults, only females with kittens are expected to show this behaviour, as male lynx do not support the females in rearing the kittens. This was clearly the case in this study. Only females with kittens displayed marked daylight activity in late autumn and early winter (small cubs and big cubs). Consistent with my results, Reinhardt & Halle (1999) stated, that the female with kittens was more active during daylight when the kittens became mobile (compared to the denning period). Long-distance movements during daylight might represent displacements to

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new hunting areas. It might be more effective to cover long distances during the day to not alert potential prey, when the kittens accompany the mother on their excursions. On the other hand, females might actively hunt during the day. This hypothesis is further supported as daylight activity of the female tracked by Reinhardt & Halle (1999) was more pronounced if she had no kill. Another possible explanation might be the onset of the hunting season in the study area in September. Females with kittens are more sensitive to human activities compared to the other reproductive states (Bunnefeld et al. 2006). Thus, females with kittens might react more strongly to hunting activities than solitary males or females and move long distances during daylight, when they are disturbed by hunters or their dogs. Anti-predator behaviour could also play an important role. Covering long distances either in the presence of small kittens or leaving them unguarded at a secondary den site might be more secure during the day, when potential predators (i.e. wolves, foxes) are less active. Thermoregulatory needs of the kittens should play a minor role during the small cubs and big cubs season, as they are assumed to be more important in the earlier stage of life. This corresponds to the finding that, female lynx leave the kittens during denning season more likely during the night than during the day (Krofel et al. 2013, own data Appendix E). However, based on localisation data only, it is difficult to assess what the female is doing during these long-distance movements. High resolution activity data (gained by accelometer in the collar) could shed light into this extraordinary movement behaviour. With these data, we would probably be able to exactly determine predation events. Furthermore, it would be of great importance to know at what time the female is accompanied by her kittens. Therefore, females and their kittens should be collared at the same time. This two components could improve our knowledge on the mother-kid relationship.

Movement patterns of females with kittens in relation to time of parturition

Movement patterns of females with kittens are strongly influenced by the presence of kittens (Fig.9). Several weeks before parturition, females decrease distances covered/week. This can be explained by the need of females to search for a suitable den site. Kaczensky (1991) reported, that the two females tracked in her study, preferred to occupy areas around the later den sites several weeks before giving birth. The results of my study further support these anecdotal observations. Furthermore, energetic constraints due to pregnancy might explain the reduction in covered distances towards parturition. After parturition, distances covered per week, distances to den site and duration away from the den site steadily increase up to the 6th week after parturition. In the 1st week, the kittens are left alone already for more than 6 hours. In line with my findings, a study in Norway showed increasing distances from the den sites with increasing kittens’ age (Van Dalum 2013). In my study, the females’ mean distance away from the den ranged from 1.56-2.71km from the 1st to the 6th week after parturition. The observed maximum distance away from the den site was 5.9km. This is in line with the findings that females kill prey within a radius of 0.73-3.5km around the den in the Swiss Jura Mountains during the period of denning (Kaczensky 1991). Also in the

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Bialowieza Primeval Forest, the movement of females with kittens was concentrated <3km around the den, for the first two months after parturition (Schmidt 1998). During the first weeks after parturition, females hunt very concentrated around the den. The increasing distance to the den site with increasing kitten age show, that the females constantly expand the area used around the den. In order to ensure hunting success, females have to permanently enlarge the hunting are presumably because of increased prey vigilance in the proximity of the den. Thus, six weeks after giving birth, females already covered remarkable distances. From the 6th until the 10th week after parturition, distances covered/week permanently decrease. This pattern might be explained by the fact, that not yet fully mobile kittens already accompany the mother on their excursions. This hypothesis is further supported by the observation that females used to maintain a den up to maximum nine weeks after parturition. In line with my findings, Krofel et al. (2013) reported females with kittens to stop returning to permanent dens when kittens are 53 (7.6 weeks) or 66 days (9.4 weeks) old. From week 10 onwards, kittens become more mobile and covered distances increase with a high amount of variation. The variation in my data might be explained by the smaller sample size towards the end of the time series. Another reasonable explanation is the availability of kills, as having or not having a prey has been shown to have a great influence on lynx activity (Podolski et al. 2013).

Interactions between male and female lynx

My study provided novel insights into the interactions between male and female lynx during the denning period: I observed frequent visits of resident male lynx at the natal den site or secondary den sites of the resident females. In 4 out of 5 lynx pairs, at least one of these visits took place 49- 52 days after parturition. In one pair, the last visit occurred 37 days after parturition. Infanticide was never observed and all females were known to be still accompanied by kittens at the end of the denning period even though in one case, the visiting male (PIRO) was not the father of the female’s (MARI) kittens (C. Breitenmoser, unpublished data). My findings correspond to the fact that replacement litters have been reported to occur in wild Eurasian lynx in August (Breitenmoser & Breitenmoser-Würsten 2008). In a well-documented case in a zoo (Kaczensky 1991), a female gave birth to a second litter exactly 100 days after the first parturition. This means, that the female has received second attention from a male about 28 days after the first parturition date. According to my observations, replacement litters would take place about 109-124 days after the first litter. This could absolutely be possible, as Kaczensky’s observations have been made in zoos, where litter lost might be replaced faster than in the wild. These results suggest, that male lynx try to increase their reproductive success by frequently checking the reproductive status of the resident females. The most astonishing case of spatial interaction was observed between NEVE and LUPO. In one case, the male LUPO had a kill in closed proximity to the natal den site of NEVE, only 12 days after the parturition date. I have no indication that he shared the kill with NEVE. Instead of avoiding competition, LUPO killed prey around the den of his offspring. The two individuals further showed

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extremely low distances (mean=3.28km) between each other. This lynx pair might be a special case, as LUPO intruded into the territory of the former resident male MISO. Intensive mate-guarding of the resident female NEVE might have been necessary in order to outcompete MISO. Nevertheless, it is astonishing that the resident male kills prey in closed proximity of the den of his offspring, as the female has to hunt successfully 3km around the den for the first two months after parturition. Up to now, male and female lynx were expected to meet mainly during the mating season (Breitenmoser & Breitenmoser-Würsten 2008). An early study on competition avoidance between male and female lynx showed, that the two sexes seldom used the same topographic compartment at the same time, especially during the period of rearing the kittens (Wölfl 1993). Contrary to these early findings by means of VHF-technology, my results showed frequent encounters between males and females, even during the period of denning. My observations suggest that there is more interaction between the two sexes than previously assumed. Virtual fences (GPS-technology) would be a great possibility to deepen our knowledge on interactions among the two sexes.

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5 Conclusion

Lynx show specific movement patterns- related to sex and reproductive state. Males are more stationary during mating season, but move longer distances between stationary phases compared to other seasons. Males as well as females without kittens show a typical pattern with peaks of long- distance movements around twilight. Females with kittens are strongly influenced by the presence of the kittens. After parturition, they are constrained by the presence of the newborns and show mostly stationary behaviour. Long-distance movements steadily increase with kittens’ age. Furthermore, females with kittens show completely different diurnal movement patterns compared to the other reproductive states. In late autumn and early winter, females with kittens show long- distance movements mainly during the daylight period. However, the reason for this remarkable behaviour remains unclear. The analysis of distances between neighbouring males and females revealed frequent interactions between the two sexes around the time of parturition. The hypothesis of separated cohabitation between resident males and females (Breitenmoser & Breitenmoser- Würsten 2008) might be not as pronounced as assumed previously. A better understanding of spatial interactions between lynx would improve our knowledge on important parameters determining the demographic status of a population, and in turn, conservation and management of the species.

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6 Acknowledgements

I wish to thank my supervisors Univ.Prof. Dipl.-Biol. Dr.rer.nat. Klaus Hackländer, Dr. Kristina Vogt and Dr. Urs Breitenmoser, for all help and valuable inputs they have given me with my thesis. While simultaneously writing on this study and working for another lynx project in the field, I gained valuable experiences every day. I am also grateful to the game wardens Anton Schmid, Bruno Dauwalder, Paul Schmid, Peter Schwendimann, Rolf Zumbrunnen, Ruedi Kunz and Walter Kunz for announcement of lynx kills and support in maintaining the box-traps. Furthermore, I thank the Federal Office for Environment and Nature (FOEN) and the hunting service of the Canton of Bern for funding the project. Last but not least, I thank my mother, without whom I would never have had the great possibility to study abroad.

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Appendices

Appendix A

Interpolated den sites (green circles) and proofed kills (red circles) for female CARA.

Interpolated den sites (green circles) and proofed kills (red circles) for female EYWA.

Interpolated den sites (green circles) and proofed kills (red circles) for female ISIS.

Interpolated den sites (green circles) and proofed kills (red circles) for female LELA.

Interpolated den sites (green circles) and proofed kills (red circles) for female MARI.

Interpolated den sites (green circles) and proofed kills (red circles) for female NEVE.

Interpolated den sites (green circles) and proofed kills (red circles) for female SUNA.

Appendix B

First, one broken-stick-model has been run for the time intervals 1-4hours. Classification between 1- 2h and 3-4h intervals was still dependent on fix interval (X-squared = 51.9, df = 1, p-value<0.05). > prop.test(table(dat$dif_time_cat,dat$move_mode),1)

2-sample test for equality of proportions with continuity correction data: table(dat$dif_time_cat, dat$move_mode) X-squared = 51.9, df = 1, p-value = 5.84e-13 alternative hypothesis: two.sided 95 percent confidence interval: 0.03380090 0.05908818 sample estimates: prop 1 prop 2 0.5779605 0.5315160

Therefore, I applied two separate models for the 1-2h and 3-4h, respectively. The best division was 1.13m/min for the 1-2h interval and 0.76m/min for the 3-4 hour categories respectively. In other words, if a lynx moved further than 68m in a one hour step, 136m in a 2 hour step, 137m in a 3 hour step, or 182m in a 4 hour step its behavioural state was attributed to long-distance movement, and stationary behaviour otherwise. A X-squared-test for equality of the proportions of behavioural states for the two categories (1-2h, 3-4h) revealed no signigicant differences (X-squared = 0.3074, df = 1, p-value = 0.5793). Thus, classification was independent from fix interval. > prop.test(table(dat$dif_time_cat,dat$move_mode),1)

2-sample test for equality of proportions with continuity correction data: table(dat$dif_time_cat, dat$move_mode) X-squared = 0.3074, df = 1, p-value = 0.5793 alternative hypothesis: two.sided 95 percent confidence interval: -0.009042084 0.016345215 sample estimates: prop 1 prop 2 0.5498904 0.5462388

Broken-stick model for the 1-2h time intervals. The best division is at 1.13m/min.

Broken-stick model for the 3-4h time intervals. The best division is at 0.76m/min.

Appendix C

GAMM performed poorly in analysing the relationship between distance covered between stationary phases and julian day as explanatory variable.

Appendix D

Histogram of the model residuals from the linear mixed model.

Residuals versus fitted plot from the linear mixed model.

Appendix E

Mean distance of females to the den site in relation to time of the day. Females with kittens stay closer to the den during the day than during the night. Thus, thermoregulatory needs of the kittens during night should be less important than the danger of dehydration during warm summer days.