Jørgen Rosvold

Reconstructing the history of a fragmented and heavily exploited red deer population using ancient and contemporary DNA

BackgroundRed deer (Cervus elaphus) have been an important human resource for millennia, experiencing intensive human influence through habitat alterations, hunting and translocation of animals. In this study we investigate a time series of ancient and contemporary DNA from Norwegian red deer spanning about 7,000 years. Our main aim was to investigate how increasing agricultural land use, hunting pressure and possibly human mediated translocation of animals have affected the genetic diversity on a long-term scale.ResultsWe obtained mtDNA (D-loop) sequences from 73 ancient specimens. These show higher genetic diversity in ancient compared to extant samples, with the highest diversity preceding the onset of agricultural intensification in the Early Iron Age. Using standard diversity indices, Bayesian skyline plot and approximate Bayesian computation, we detected a population reduction which was more prolonged than, but not as severe as, historic documents indicate. There are signs of substantial changes in haplotype frequencies primarily due to loss of haplotypes through genetic drift. There is no indication of human mediated translocations into the Norwegian population. All the Norwegian sequences show a western European origin, from which the Norwegian lineage diverged approximately 15,000 years ago.ConclusionsOur results provide direct insight into the effects of increasing habitat fragmentation and human hunting pressure on genetic diversity and structure of red deer populations. They also shed light on the northward post-glacial colonisation process of red deer in Europe and suggest increased precision in inferring past demographic events when including both ancient and contemporary DNA.

The rise and fall of wild boar in a northern environment: Evidence from stable isotopes and subfossil finds

Here we use long-term data from Holocene archaeological bone assemblages in order to investigate how changes in climate, vegetation and human land use might have influenced the distribution of wild boar (Sus scrofa) in Norway during the Holocene. We combine four lines of evidence: an analysis of stable isotopes of carbon and nitrogen in a time series of subfossil teeth, distribution data of bone finds from 31 archaeological sites, changes in the relative abundance of wild ungulates from four of these sites and historical documents. A significant change in Sus diet, indicated by δ15N levels, was found. This coincided with the spread of agriculture and indicates a change from wild boar to domestic pigs. Based on this finding the distributional data show that the Norwegian wild boar was limited to the coastal broadleaved forests even during the most optimal climatic period. A reduction in the relative abundance of wild boar, and later extinction, seems to coincide with a reduction in such habitat, caused partly by climatic change but more pronouncedly by human habitat alterations, and competition with domestic animals. The data indicate that the primary factor limiting the northern distribution of wild boar is the availability of food resources.

Ancient DNA reveals prehistoric habitat fragmentation and recent domestic introgression into native wild reindeer

Introgression and admixture from domestic or foreign conspecifics into wild populations are of great concern in wildlife conservation. The issue is of particular interest in ungulates where translocations and re-introductions have been common practice. In Europe, the only large remaining wild populations of reindeer (Rangifer tarandus L.) are found in the mountainous habitats of southern Norway. These populations have during the last centuries been exposed to extensive habitat modifications and periods of contact with domestic reindeer. Through analyses of ancient and extant mitochondrial DNA (mtDNA) we document extensive intra- and inter-population genetic changes during the last millennium. Our data indicate population reduction within a short time interval during the 11th–12th century during a period when mass trapping of reindeer was common. Significant differentiation between the ancient herds suggests an ancient genetic structuring of the reindeer herds in southern Norway, although not as strong as between modern herds. Two different mtDNA lineages characterized the ancient herds. A Bayesian approach to reconstruct the recent evolutionary history suggests that the reindeer herds in southern Norway originate from two populations separated in different refugia during the last glacial period. The presence of two additional extant lineages, characteristic of domestic herds, suggests substantial introgression into the native wild reindeer. The putatively different refugial origins of the lineages represented by the extant herds in Rondane/Dovre, Hardangervidda and those with a mainly domestic origin may well reflect different adaptations to environmental conditions, including degree of human interference. Further research on this issue would provide important insights for conservation priorities and a sustainable and flexible management strategy for the remaining wild reindeer herds in the Scandinavian mountains.

Long-term morphological changes in the skeleton of red deer (Artiodactyla, Cervidae) at its northern periphery

Abstract Large-scale variation in mammalian body size has often been found to be related to environmental conditions. A general finding among large herbivores is that body size increases with decreasing temperature (Bergmanns rule), because animals with larger body size have better heat conservation or fasting tolerance, or because higher quality forage occurs in colder environments. Using a data set on the skeletal morphology of Norwegian red deer (Artiodactyla, Cervidae: Cervus elaphus) spanning the last approximately 7,100 years, we document an inverse relationship between climatic conditions and body size. The size of Norwegian red deer, as estimated from both teeth and weight-bearing bones, was significantly larger during the warmer and wetter middle Holocene than it is today. However, the reduction in body size does not seem to be related to changing climatic conditions. Rather, this decrease happened during a period of large-scale human-mediated habitat fragmentation, increased populations of domestic herbivores, and heavy hunting pressure that reduced population density. The size of teeth was reduced as much as, or even more than, the size of weight-bearing bones, which indicates an evolutionary response rather than phenotypic plasticity to changing forage and environmental conditions. Decreased body size may be a general response in wild ungulates to a more human-dominated landscape, resulting from reduced access to optimal habitats and high adult hunting mortality.

Cervids in a dynamic northern landscape: Holocene changes in the relative abundance of moose and red deer at the limits of their distributions

It is predicted that future climate change will have a significant impact on the distribution of large ungulates on a continental scale. At the same time, changes in human land use on a more local scale may affect their distribution and dispersal abilities, possibly confounding the effects of climate. We analyze changes in the Holocene distribution and relative abundance of Alces alces (moose) and Cervus elaphus (red deer) skeletal remains along an overlapping range boundary of these species in western Norway. As moose and red deer are adapted to different climatic conditions we would expect the distribution of finds to reflect large-scale changes in climate. In accordance with this prediction our results indicate that red deer became the predominant ungulate in this area during the mid-Holocene warm period, c. 8000–4000 cal. BP. Contrary to this, remains of moose became even less abundant in the subsequent colder period to the present. This decrease seems tied to the spread of agriculture and deforestation, indicating the importance of considering changes in land use when predicting future changes in ungulate distribution.

Rapid Localization of Bone Fragments on Surfaces using Back-Projection and Hyperspectral Imaging†

Manual localization of bone fragments on the ground or on complex surfaces in relation to accidents or criminal activity may be time‐consuming and challenging. It is here investigated whether combining a near‐infrared hyperspectral camera and chemometric modeling with false color back‐projection can be used for rapid localization of bone fragments. The approach is noninvasive and highlights the spatial distribution of various compounds/properties to facilitate manual inspection of surfaces. Discriminant partial least squares regression is used to classify between bone and nonbone spectra from the hyperspectral camera. A predictive model (>95% prediction ability) is constructed from raw chicken bones mixed with stone, sand, leaves, moss, and wood. The model uses features in the near‐infrared spectrum which may be selective for bones in general and is able to identify a wide variety of bones from different animals and contexts, including aged and weathered bone.