Scale-dependent effects of summer density on autumn mass in reindeer

The ongoing dispute about reindeer overabundance in the West Finnmark (Norway) herding region has accentuated the need for an in-depth understanding of the density-dependent and -independent processes driving this pastoral system, as well as the spatial and temporal scale(s) they operate on. Using 20 604 records of individual male reindeer yearlings we assessed the spatial and temporal variation in animals’ performance (measured by their autumn carcass mass), and investigated summer density dependent effects on autumn carcass masses at different scales. We defined three spatial scales; a regional scale represented by the whole summer range of West Finnmark, a sub-regional scale represented by the mainland (14) and the island (11) summer districts, and a fine scale represented by eight individual summer districts. We defined two temporal scales; the whole collection phase (13 years) and a temporal dimension based on the three periods of population growth. We found carcass masses to be higher at island than at mainland and to vary among districts. Effect of period was found at the regional, sub-regional and often at the district scale. The autumn carcass masses were sensitive to density at West Finnmark and mainland scales, but not at island scale, the effect being negative. This suggests intra-specific competition for summer forage due to consistent higher density resulting in reduced range quality at mainland as compared to island. On the finest scale the density effect was highly variable. Response of carcass mass to density appeared to be scale dependent both in space and time at regional and sub-regional scales. These findings underline the importance, for skilful management, of site specific biological understanding of (1) the density dependent processes and (2) the spatial and temporal scales these processes are operating on. Adaptive management strategies for sustainable use of the summer forage resources in West Finnmark have therefore to be district specific.Skala-avhengige virkninger av antallet rein på høstslaktevektene i Vest-FinnmarkAbstract in Norwegian / Sammendrag: Den stadig pågående diskusjon omkring reintall og overbelastning av beitene i Vest- Finnmark krever en bedre forståelse av tetthetsavhengige, så vel som tetthetsuavhengige prosesser som påvirker dette beitesystemet og på hvilke skalaer disse opererer. Vi benyttet 20 604 slaktevekter av varit (1,5 års gamle bukker) før brunst for å undersøke variasjonen i tid og rom i disse, og om sommerbeitebelegget på ulike skalaer påvirket vektene. Vi definerte tre romlig skalaer: 1) hele sommerbeiteområdet i Vest-Finnmark, 2) to underregioner: innlandsdistriktene samlet og øy/halvøydistriktene samlet og 3) det enkelte sommerbeitedistrikt. På distriktsnivå ble bare slaktedata fra 8 distrikt benyttet. Videre ble to tidsskalaer definert: 1) hele perioden samlet, 2) tre perioder basert på utviklingen i reintallet i Vest-Finnmark - økning i periode 1 (1983-87) og i periode 3 (2001-2004) og nedgang i periode 2 (1996 -2000). Slaktevektene var høyere for øy/halvøydistriktene sammenlignet med innlandsdistriktene samlet og varierte mellom distrikt. Periode påvirket også slaktevektene regionalt, subregionalt og ofte på distriktsnivå. Vi fant en negativ tetthetsavhengig effekt på slaktevektene for Vest-Finnmark samlet. Det samme gjaldt for innlandsdistriktene samlet, men ikke for øy/halvøydistriktene samlet. Dette forklares ved fødekonkurranse på innlandsdistriktenes sommerbeiter, sannsynligvis på grunn av at vedvarende høye tettheter har forringet beitekvaliteten, sammenlignet med øy/halvøydistriktene samlet. På distriktsnivå varierte effekten av tetthet. Resultatene tyder videre på skala-avhengige tetthetseffekter i tid og rom, i Vest-Finnmark samlet, så vel som på innlands- og øy/halvøynivå. Tetthet er et mangesidig og komplekst begrep som ikke kan sees uavhengig av skala. Det er derfor viktig å analysere slike prosesser på flere skalanivå for bedre å kunne forstå samspillet mellom vegetasjon og beitedyr. Dette innebærer i praksis at hvert sommerdistrikt (siida), som er den funksjonelle enheten i forvaltningssammenheng, må behandles uavhengig og danne grunnenheten i en fornuftig forvaltning

Effect of "owners" selection strategies on autumn weight in reindeer (Rangifer t. tarandus) calves

Many northern indigenous peoples, including the Sami are dependent on reindeer herding for their livelihood. In view of the socio-cultural and economical importance of reindeer herding, emphasis should be put on appropriate herd structure and selection strategies that maximise marketable products, such as meat (the primary marketable product nowadays). Empirical observations reveal that within a herd, some owners seem to have better productivity in term of carcass autumn weight of calves, than others. We hypothesized that there may be an "owner" effect in reindeer herding, i.e. some owners may be applying particular selection strategies that might be beneficial. We investigated this in three reindeer grazing districts in South Norway, using mixed linear models. We found that autumn carcass weight of calves varied significantly with year and "owner" within herd in all three districts. Consistently some particular owners within a herd had higher average autumn carcass weight of their calves than others. We attributed this difference to "individual selection strategies", meaning that some owners may follow more accurately the sex, age and weight-based recommended strategy and in addition, they may make superior choices when selecting animals for slaughtering. We conclude that individual owners have the capability, through appropriate selection decisions to improve the average annual autumn weight of their reindeer calves. This might be an important aspect of "Traditional Ecological Knowledge", in addition to the recommended modern sex, age and weight-based selection criteria

Highly competitive reindeer males control female behavior during the rut

During the rut, female ungulates move among harems or territories, either to sample mates or to avoid harassment. Females may be herded by a male, may stay with a preferred male, or aggregate near a dominant male to avoid harassment from other males. In fission-fusion group dynamics, female movement is best described by the group's fission probability, instead of inter-harem movement. In this study, we tested whether male herding ability, female mate choice or harassment avoidance influence fission probability. We recorded group dynamics in a herd of reindeer Rangifer tarandus equipped with GPS collars with activity sensors. We found no evidence that the harassment level in the group affected fission probability, or that females sought high rank (i.e. highly competitive and hence successful) males. However, the behavior of high ranked males decreased fission probability. Male herding activity was synchronous with the decrease of fission probability observed during the rut. We concluded that male herding behavior stabilized groups, thereby increasing average group size and consequently the opportunity for sexual selection

Comparative response of Rangifer tarandus and other northern ungulates to climatic variability

To understand the factors influencing life history traits and population dynamics, attention is increasingly being given to the importance of environmental stochasticity. In this paper, we review and discuss aspects of current knowledge concerning the effect of climatic variation (local and global) on population parameters of northern ungu¬lates, with special emphasis on reindeer/caribou (Rangifer tarandus). We also restrict ourselves to indirect effects of climate through both forage availability and quality, and insect activity. Various authors have used different weather variables; with sometime opposite trends in resulting life history traits of ungulates, and few studies show consistent effects to the same climatic variables. There is thus little consensus about which weather variables play the most sig¬nificant role influencing ungulate population parameters. This may be because the effects of weather on ungulate pop¬ulation dynamics and life history traits are scale dependent and it is difficult to isolate climatic effects from density dependent factors. This confirms the complexity of the relationship between environment and ecosystem. We point out limits of comparability between systems and the difficulty of generalizing about the effect of climate change broadly across northern systems, across species and even within species. Furthermore, insect harassment appears to be a key climate-related factor for the ecology of reindeer/caribou that has been overlooked in the literature of climatic effects on large herbivores. In light of this, there is a need for further studies of long time series in assessing effects of climate variability on reindeer/caribou

Woodland caribou calf recruitment in relation to calving/post-calving landscape composition

Since the 1990s, Newfoundland’s woodland caribou (Rangifer tarandus caribou) population has declined by an estimated 66%. Low calf recruitment has been associated to the decline, possibly triggered by increasing calf predation and/or decreasing resources. To investigate the role of landscape composition in this system, we studied the yearly (2005-2008) calving/post-calving range (CPCR) of 104 satellite-collared females belonging to six herds. We mapped nine disturbance factors (e.g. roads, logging, etc), as well as vegetation cover types (e.g. coniferous, deciduous forests, etc), and determined the total area they occupied within CPCRs yearly for each herd. Using an information theoretic approach, we assessed the model that best explained variation in recruitment using these components. Based on corrected Akaike Information Criterion, the model that best explained variation in calf recruitment included total disturbance and deciduous forest area, both showing the expected negative relationship with calf recruitment. Other landscape variables among the models with ΔAICc < 2 were mixed forest, also with a suggested negative relationship, and barrens and wetlands with a significant positive trend. This study highlights the need to minimize total disturbance footprint and account for resulting changes in forest composition within CPCRs during land use planning. Expanding forestry operations and road infrastructure in critical woodland caribou habitat across Canada may additionally contribute to habitat loss via fragmentation. This in turn, may lead to range recession beyond the initial local avoidance footprint. We see the possibility of using calf recruitment models based on landscape parameters, among others, to predict the impact of new industrial developments on calf recruitment

Effect of calf stimulation on milk ejection in reindeer (Rangifer tarandus)

The objective of this study was to establish methods for stimulating the milk ejection in reindeer kept for milking purpose. Calves were used to stimulate milk does’ let down. In experiment 1, five does were allowed olfactory, acoustic and visual contact with their calves during milking, whereas four does were milked in isolation. The treatment of the groups was alternated every day during the eight days experiment. Olfactory, acoustic and visual contact with the calf did not influence the doe’s milk yield. The milk yield varied significantly between individual females within treatment (P < 0.01). In experiment 2, the calves were allowed to suckle their mother for a short period (two seconds) prior to milking being initiated. The same alternate design as in experiment 1 with groups consisting of three and two animals respectively was used, and the experiment lasted four days. The pre-suckling stimulation significantly increased the milk ejection measured as milk yield (P < 0.05), and the residual milk after the treatment was negectible. Moreover, the milk ejection varied between individual females within treatment (P < 0.05). We conclude that it is possible to achieve a complete milk removal by machine milking after the does have been pre-stimulated by suckling of calves. Olfactory, acoustic and visual contact with calves during milking failed to influence the milk ejection in this study. However, the results have to be interpreted with caution due to limited sample size.Abstract in Norwegian / Sammendrag: Formålet med dette forsøket var å prøve ut ulike metoder for å stimulere nedgivninga av melk hos rein. Kalvene ble tatt i bruk for å stimulere nedgivninga. I forsøk 1 hadde simla lyd-, lukt og synskontakt med kalven mens melkingen pågikk. Vi benyttet et ”switch back design” der fem simler hadde kontakt med kalven under melkingen og fire ble melket uten kontakt. Behandlingen ble byttet om annenhver dag i de åtte dagene forsøket varte. Lyd-, lukt og synskontakt med kalven under melking hadde ingen innvirkning på melkemengden ved maskinmelking. Det var imidlertid individuell variasjon i hvor mye melk man oppnådde hos simlene (P < 0.01). I forsøk 2 lot vi kalvene suge simlene en kort stund før simlene ble melket. Kalven ble sluppet inn til simla og sugingen ble avbrutt etter to sekunder. Deretter ble simla ført inn for maskinmelking. Forsøket varte i fire dager og vi benyttet samme ”switch back design” som i forsøk 1, med grupper bestående av henholdsvis to og tre dyr. Stimuleringa med suging hadde en signifikant innvirkning på nedgivninga. (P < 0.05), og mengden gjenværende melk var minimal. Dessuten var det en signifikant individuell variasjon i melkemengden innen behandlingen (P < 0.05). Vi konkluderer med at det er mulig å oppnå en fullstendig tømming av juret ved maskinmelking dersom simlene først er blitt stimulert med suging av kalven. Lyd-, lukt- og synskontakt med kalven under melking hadde ingen innvirkning på nedgivninga av melk i dette forsøket. Resultatene må imidlertid tolkes med varsomhet siden det statistiske utvalget er begrenset

Using behavior and social associations to assess the welfare of a captive flock of Caribbean flamingos (Phoenicopterus ruber)

While the four main roles of zoos are education, research, conservation, and entertainment, the most important goal of zoos is to ensure good animal welfare. Animal welfare is generally assessed by observing the animals for indicators of poor welfare in three categories: health, physiological condition, and behavior. A common indicator of poor welfare is decreased reproduction, which is a problem in many captive flamingo flocks. We assessed the welfare of the flamingo flock at Zoo de Granby using behavior patterns, environmental effects, visitor effects, and social associations. Our results suggest that the behavior patterns differ between a wild population and the Zoo de Granby flock. We found an increased frequency of preening during periods of high humidity, and increased aggressive behaviors during periods of increased heat and humidity. Visitor variables had an effect on most behaviors but did not affect vigilance frequency. Contrary to previous literature, several of the Zoo de Granby pairings were not maintained over time. Association strengths were not different from their previous pairings, or between the nonbreeding and breeding season. Our findings suggest that flamingo behavior is affected by captivity although we do not believe it is a negative effect. We recommend that Zoo de Granby investigate the effect of animal keeper presence and the effect of wing clipping on copulation. Our association findings allow us to provide Zoo de Granby with information regarding strongly associated pairings who should not be separated in the event of a transaction between institutions

The Content of Reindeer Male Vocalisations: Acoustic Cues to Age and Weight

Acoustic signals are widely used by animals for communication and the regulation of interactions. Moreover, some acoustic parameters of animal vocalisations have been shown to reliably indicate male quality and play a role in mate and rival assessment. For example, in some deer species, formant frequencies act as cues to body size, and lower formant values and spacing are selected by females in a mate choice context. Reindeer possess a peculiar vocal tract anatomy involving a laryngeal air sac which probably acts as an additional filter, making it a candidate species for novel investigations in the field of bioacoustics. We investigated whether some acoustic parameters were good indicators of age and body weight (used as an index for body size). We did this by performing acoustic analyses using recordings collected from a semi-domesticated reindeer population in northern Finland. This study first highlights the complexity of acoustic parameter extraction from reindeer male vocalisations, likely due to the presence of the laryngeal air sac. We found age of subadult males (aged 2.5-4.5 years) to be negatively correlated with formant F3 and formant spacing, suggesting that their vocalisations convey information on the caller’s age. Formant frequencies were not affected by male body weight, suggesting they may not provide information on male size in our population. In contrast, we found that heavier males had a lower formant spacing. It is thus probably a key acoustic parameter in mate and rival assessment as it gives an honest indication on male body weight. We discuss the importance of reliable acoustic cues to size and quality indices in sexual selection contexts. However, it is highly likely that reindeer males and females rely on other signals as well, such as visual and olfactory cues, to gain information on male attributes. We suggest that further investigation is needed to better understand how the laryngeal air sac affects vocal production

Shit happens - a glimpse into males’ mating tactics in a polygynous ungulate - the reindeer

This is about the two big "guys", Spot and Mika, and their endeavour to propagate their genes during the mating season 2007. They were 6 and 5 years old weighting 172 and 141 kg before rut, respectively. Together with 23 other males (one 5 yrs, two 4 yrs, three 3 yrs, six 2 yrs and eleven 1 yr old) they roamed within a ~15 km2 fenced area competing for access to 87 females. Indeed, the competition was intense and all males present contributed to the dynamic observed. Especially Hot, the heaviest 4 yrs old male weighing 155 kg before rut, played a prominent role - in addition to Spot and Mika, their mating tactics being highly dynamic. However there is no short cut to success - strength have to be coupled with smartness - but shit happens - as we'll see

Modelling reindeer rut activity using on‐animal acoustic recorders and machine learning

For decades, researchers have employed sound to study the biology of wildlife, with the aim to better understand their ecology and behaviour. By utilizing on-animal recorders to capture audio from freely moving animals, scientists can decipher the vocalizations and glean insights into their behaviour and ecosystem dynamics through advanced signal processing. However, the laborious task of sorting through extensive audio recordings has been a major bottleneck. To expedite this process, researchers have turned to machine learning techniques, specifically neural networks, to streamline the analysis of data. Nevertheless, much of the existing research has focused predominantly on stationary recording devices, overlooking the potential benefits of employing on-animal recorders in conjunction with machine learning. To showcase the synergy of on-animal recorders and machine learning, we conducted a study at the Kutuharju research station in Kaamanen, Finland, where the vocalizations of rutting reindeer were recorded during their mating season. By attaching recorders to seven male reindeer during the rutting periods of 2019 and 2020, we trained convolutional neural networks to distinguish reindeer grunts with a 95% accuracy rate. This high level of accuracy allowed us to examine the reindeers' grunting behaviour, revealing patterns indicating that older, heavier males vocalized more compared to their younger, lighter counterparts. The success of this study underscores the potential of on-animal acoustic recorders coupled with machine learning techniques as powerful tools for wildlife research, hinting at their broader applications with further advancement and optimization