Rasmus Worsøe Havmøller

Dr. Rasmus Worsøe Havmøller

orcid

Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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3 May 2020 in Conservation Biology
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MNMichael Noonan
Michael Noonan
CFChristen H. Fleming
Christen H. Fleming
MTMarlee A. Tucker
Marlee A. Tucker
RKRoland Kays
Roland Kays
AHAutumn‐Lynn Harrison
Autumn‐Lynn Harrison
JCJustin M. Calabrese
Justin M. Calabrese
Accurately quantifying species’ area requirements is a prerequisite for effective area‐based conservation. This typically involves collecting tracking data on species of interest and then conducting home‐range analyses. Problematically, autocorrelation in tracking data can result in space needs being severely underestimated. Based on the previous work, we hypothesized the magnitude of underestimation varies with body mass, a relationship that could have serious conservation implications. To evaluate this hypothesis for terrestrial mammals, we estimated home‐range areas with global positioning system (GPS) locations from 757 individuals across 61 globally distributed mammalian species with body masses ranging from 0.4 to 4000 kg. We then applied block cross‐validation to quantify bias in empirical home‐range estimates. Area requirements of mammals 1, meaning the scaling of the relationship changed substantially at the upper end of the mass spectrum.

12 March 2020 in Journal of Zoology
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Journal Article
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RHRasmus Worsøe Havmøller
Rasmus Worsøe Havmøller
NJN. S. Jacobsen
N. S. Jacobsen
NSN. Scharff
N. Scharff
FRF. Rovero
F. Rovero
FZFridolin Zimmermann
Fridolin Zimmermann
Studying activity patterns and temporal overlap among carnivores and their putative prey is difficult because of their secretive and elusive nature. With large carnivores declining worldwide, it is imperative for conservation planning that we understand how large carnivores interact with their prey and competitors. Camera trapping offers a promising avenue to address this issue. We investigated temporal overlap between male and female leopards, their known and putative prey as well as their competitor, the spotted hyenas, in the Udzungwa Mountains of Tanzania. Data consisted of 4297 independent events from a 30 min interval criterion from 164 camera trap sites we sampled. Leopards were captured by camera traps throughout the day, with male and female leopards showing significantly different activity patterns (P < 0.001) indicating sexual segregation in activity patterns, with male leopards being more nocturnal than female leopards. Leopards had significantly different activity patterns from that of the majority of their prey, with yellow baboons, that displayed peak activity during midday, that had the least overlap. Moreover, both male and female leopards had significantly different activity patterns from that of spotted hyenas (P = <0.001), with female leopards appearing to be inactive during hours with peak hyena activity. We conclude that systematic camera trapping is a useful tool to study activity patterns and temporal niche interactions between sympatric carnivores and, to a lesser extent, their prey.

25 March 2023 in Animal Biotelemetry
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TWTimm A. Wild
Timm A. Wild
LSLouis van Schalkwyk
Louis van Schalkwyk
PVPauli Viljoen
Pauli Viljoen
GHGeorg Heine
Georg Heine
NRNina Richter
Nina Richter
MWMartin Wikelski
Martin Wikelski
Bio-telemetry from small tags attached to animals is one of the principal methods for studying the ecology and behaviour of wildlife. The field has constantly evolved over the last 80 years as technological improvement enabled a diversity of sensors to be integrated into the tags (e.g., GPS, accelerometers, etc.). However, retrieving data from tags on free-ranging animals remains a challenge since satellite and GSM networks are relatively expensive and or power hungry. Recently a new class of low-power communication networks have been developed and deployed worldwide to connect the internet of things (IoT). Here, we evaluated one of these, the Sigfox IoT network, for the potential as a real-time multi-sensor data retrieval and tag commanding system for studying fauna across a diversity of species and ecosystems. We tracked 312 individuals across 30 species (from 25 g bats to 3 t elephants) with seven different device concepts, resulting in more than 177,742 successful transmissions. We found a maximum line of sight communication distance of 280 km (on a flying cape vulture [Gyps coprotheres]), which sets a new documented record for animal-borne digital data transmission using terrestrial infrastructure. The average transmission success rate amounted to 68.3% (SD 22.1) on flying species and 54.1% (SD 27.4) on terrestrial species. In addition to GPS data, we also collected and transmitted data products from accelerometers, barometers, and thermometers. Further, we assessed the performance of Sigfox Atlas Native, a low-power method for positional estimates based on radio signal strengths and found a median accuracy of 12.89 km (MAD 5.17) on animals. We found that robust real-time communication (median message delay of 1.49 s), the extremely small size of the tags (starting at 1.28 g without GPS), and the low power demands (as low as 5.8 µAh per transmitted byte) unlock new possibilities for ecological data collection and global animal observation.

12 June 2019 in PLOS ONE
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RHRasmus Worsøe Havmøller
Rasmus Worsøe Havmøller
STSimone Tenan
Simone Tenan
NSNikolaj Scharff
Nikolaj Scharff
FRFrancesco Rovero
Francesco Rovero
Determining correlates of density for large carnivores is important to understand their ecological requirements and develop conservation strategies. Of several earlier density studies conducted globally, relatively few addressed a scale (usually >1000 km2) that allows inference on correlates of density over heterogeneous landscapes. We deployed 164 camera trap stations covering ~2500 km2 across five areas characterized by broadly different vegetation cover in the Udzungwa Mountains, Tanzania, to investigate correlates of density for a widespread and adaptable carnivore, the leopard (Panthera pardus). We modelled data in a spatially explicit capture-recapture framework, with both biotic and abiotic covariates hypothesised to influence density. We found that leopard density increased with distance to protected area boundary (mean±SE estimated effect = 0.44±0.20), a proxy for both protected area extent and distance from surrounding human settlements. We estimated mean density at 4.22 leopards/100 km2 (85% CI = 3.33‒5.35/100 km2), with no variation across habitat types. Results indicate that protected area extent and anthropogenic disturbance limit leopard populations whereas no support was found for prey availability and trap array as drivers of leopard density. Such vulnerability is relevant to the conservation of the leopard, which is generally considered more resilient to human disturbance than other large cats. Our findings support the notion that protected areas are important to preserve viable population of leopards, increasingly so in times of unprecedented habitat fragmentation. Protection of buffer zones smoothing the abrupt impact of human activities at reserve edges also appears of critical conservation relevance.

19 April 2019 in PLOS ONE
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NCNathalie Cavada
Nathalie Cavada
RHRasmus Worsøe Havmøller
Rasmus Worsøe Havmøller
NSNikolaj Scharff
Nikolaj Scharff
FRFrancesco Rovero
Francesco Rovero
With biodiversity facing unparalleled threats from anthropogenic disturbance, knowledge on the occurrences of species and communities provides for an effective and fast approach to assess their status and vulnerability. Disturbance is most prominent at the landscape-level, for example through habitat loss from large-scale resource extraction or agriculture. However, addressing species responses to habitat changes at the landscape-scale can be difficult and cost-ineffective, hence studies are mostly conducted at single areas or habitat patches. Moreover, there is a relative lack of studies on communities, as opposed to focal species, despite the former may carry more comprehensive information. Here, we used a multi-region, multi-species hierarchical occupancy model to study a meta-community of mammals detected by camera traps across five distinct areas within a heterogeneous landscape in Tanzania, and aimed to assess responses to human disturbance and environmental variables. Estimated species richness did not vary significantly across different areas, even though these held broadly different habitats. Moreover, we found remarkable consistency in the positive effect of distance to human settlements, a proxy for anthropogenic disturbance, on community occupancy. The positive effect of body size and the positive effect of proximity to rivers on community occupancy were also shared by communities. Results yield conservation relevance because: (1) the among-communities consistency in responses to anthropogenic disturbance, despite the heterogeneity in sampled habitats, indicates that conservation plans designed at the landscape-scale may represent a comprehensive and cost-efficient approach; (2) the consistency in responses to environmental factors suggests that multi-species models are a powerful method to study ecological patterns at the landscape-level.

23 October 2018 in BMC Ecology and Evolution
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JPJohanna L.A. Paijmans
Johanna L.A. Paijmans
ABAxel Barlow
Axel Barlow
Daniel W. G. FörsterDaniel W. G. Förster
Daniel W. G. Förster
KHKirstin Henneberger
Kirstin Henneberger
MMMatthias Meyer
Matthias Meyer
Michael HofreiterMichael Hofreiter
Michael Hofreiter
Resolving the historical biogeography of the leopard (Panthera pardus) is a complex issue, because patterns inferred from fossils and from molecular data lack congruence. Fossil evidence supports an African origin, and suggests that leopards were already present in Eurasia during the Early Pleistocene. Analysis of DNA sequences however, suggests a more recent, Middle Pleistocene shared ancestry of Asian and African leopards. These contrasting patterns led researchers to propose a two-stage hypothesis of leopard dispersal out of Africa: an initial Early Pleistocene colonisation of Asia and a subsequent replacement by a second colonisation wave during the Middle Pleistocene. The status of Late Pleistocene European leopards within this scenario is unclear: were these populations remnants of the first dispersal, or do the last surviving European leopards share more recent ancestry with their African counterparts? In this study, we generate and analyse mitogenome sequences from historical samples that span the entire modern leopard distribution, as well as from Late Pleistocene remains. We find a deep bifurcation between African and Eurasian mitochondrial lineages (~ 710 Ka), with the European ancient samples as sister to all Asian lineages (~ 483 Ka). The modern and historical mainland Asian lineages share a relatively recent common ancestor (~ 122 Ka), and we find one Javan sample nested within these. The phylogenetic placement of the ancient European leopard as sister group to Asian leopards suggests that these populations originate from the same out-of-Africa dispersal which founded the Asian lineages. The coalescence time found for the mitochondrial lineages aligns well with the earliest undisputed fossils in Eurasia, and thus encourages a re-evaluation of the identification of the much older putative leopard fossils from the region. The relatively recent ancestry of all mainland Asian leopard lineages suggests that these populations underwent a severe population bottleneck during the Pleistocene. Finally, although only based on a single sample, the unexpected phylogenetic placement of the Javan leopard could be interpreted as evidence for exchange of mitochondrial lineages between Java and mainland Asia, calling for further investigation into the evolutionary history of this subspecies.