Search publications of the members of the Royal Belgian institute of natural Sciences
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How much does a tropical forest elevational gradient contribute to biodiversity? Insights from the ant communities of Mt. Wilhelm.
- Mountain slopes are known to promote the diversity and endemism of most taxa. Consequently, turnover of species is expected to be increased along elevational gradients compared to more uniform lowland areas of tropical forests. Mt. Wilhelm, the highest peak of Papua New Guinea, represents one of the last complete altitudinal forest transects with high-levels of biodiversity and pristine forests all along. We studied species diversity and distribution of the Mt. Wilhelm ant communities from 200 m a.s.l. up to tree line at 3700 m a.s.l., using a wide scope of sampling techniques. For the first time, the ants were sampled across different forest strata and at equally spaced elevational bands (500 m a.s.l.) along the complete gradient (257 species in total). The ants occurred up to 2700 m a.s.l. with general decline of their abundance and species richness with altitude, but not in the same way across forest strata. While the species occurrences linearly declined on the ground, they were highest at mid elevations on the vegetation. Species richness peaked at mid altitudes in all strata. Species composition varied both with sampled stratum and elevation, and there was an increase of soil-nesting species sampled on vegetation with increasing altitude. Most species occurred only in one or two elevational sites and there was no difference in the mean elevational range between ground-nesting and arboreal-nesting species. A simple model based on the species accumulation curves suggested that the Mt. Wilhelm ant species richness is two-fold increased, if rarefied to and compared with the same number of individuals as sampled in the lowlands. Our study demonstrates that pristine rainforests of Mt. Wilhelm considerably boost species diversity and endemism, and as such they should be of high conservation priority.
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Distance-decay of compositional similarity in ground but not in canopy ant assemblages in a tropical rainforest
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Exploring the ecology of arboreal ants in a tropical forest
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La estructura de las redes de coocurrencia de hormigas y plantas son similares en el dosel y el sotobosque de una selva húmeda tropical
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Capítulo 13. Glosario de morfología.
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A new record of Gunnellichnus moghraensis from the Middle Miocene of Belgium, with some remarks on the origin of this seemingly uncommon ichnospecies
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Country-scale InSAR monitoring for settlement and uplift damage calculation in architectural heritage structures
- The article proposes a methodology for assessing the development of damage in building structures, subjected to differential settlement and uplift, using the analysis of Interferometry Synthetic Aperture Radar (InSAR) data. The proposed methodology is targeted towards general applicability, capable of providing assessment results for measurements over wide geographic areas and for varying structural typologies. The methodology is not limited to ground movement measurements linked to tunnelling, as is the common case. Instead it extends to the monitoring of arbitrary movement in buildings, for example, due to ground consolidation, water table changes or excavation. The methodology is designed for use alongside patrimonial building databases, from which data on individual building geometry and typology are extracted on a region or country scale. Ground movement monitoring data are used for the calculation of the building deformation, expressed in different types of deformation parameters. The combined use of this data with analytical models for settlement damage classification in building structures enables the assessment in patrimonial building structures, at a country scale. The methodology is elaborated and applied on the patrimonial inventory of Belgium for the evaluation of potential settlement and uplift damage on buildings over a period of nearly three decades. The analysis results are compared to on-site observations.
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Dental microwear as a behavioral proxy for distinguishing between canids at the Upper Paleolithic (Gravettian) site of Předmostí, Czech Republic
- Morphological and genetic evidence put dog domestication during the Paleolithic, sometime between 40,000 and 15,000 years ago, with identification of the earliest dogs debated. We predict that these earliest dogs (referred to herein as protodogs), while potentially difficult to distinguish morphologically from wolves, experienced behavioral shifts, including changes in diet. Specifically, protodogs may have consumed more bone and other less desirable scraps within human settlement areas. Here we apply Dental Microwear Texture Analysis (DMTA) to canids from the Gravettian site of Předmostí (approx. 28,500 BP), which were previously assigned to the Paleolithic dog or Pleistocene wolf morphotypes. We test whether these groups separate out significantly by diet-related variation in microwear patterning. Results are consistent with differences in dietary breadth, with the Paleolithic dog morphotype showing evidence of greater durophagy than those assigned to the wolf morphotype. This supports the presence of two morphologically and behaviorally distinct canid types at this middle Upper Paleolithic site. Our primary goal here was to test whether these two morphotypes expressed notable differences in dietary behavior. However, in the context of a major Gravettian settlement, this may also support evidence of early stage dog domestication. Dental microwear is a behavioral signal that may appear generations before morphological changes are established in a population. It shows promise for distinguishing protodogs from wolves in the Pleistocene and domesticated dogs from wolves elsewhere in the archaeological record.
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Ancient DNA suggests modern wolves trace their origin to a Late Pleistocene expansion from Beringia
- Grey wolves (Canis lupus) are one of the few large terrestrial carnivores that have maintained a wide geographical distribution across the Northern Hemisphere throughout the Pleistocene and Holocene. Recent genetic studies have suggested that, despite this continuous presence, major demographic changes occurred in wolf populations between the Late Pleistocene and early Holocene, and that extant wolves trace their ancestry to a single Late Pleistocene population. Both the geographical origin of this ancestral population and how it became widespread remain unknown. Here, we used a spatially and temporally explicit modelling framework to analyse a data set of 90 modern and 45 ancient mitochondrial wolf genomes from across the Northern Hemisphere, spanning the last 50,000 years. Our results suggest that contemporary wolf populations trace their ancestry to an expansion from Beringia at the end of the Last Glacial Maximum, and that this process was most likely driven by Late Pleistocene ecological fluctuations that occurred across the Northern Hemisphere. This study provides direct ancient genetic evidence that long‐range migration has played an important role in the population history of a large carnivore, and provides insight into how wolves survived the wave of megafaunal extinctions at the end of the last glaciation. Moreover, because Late Pleistocene grey wolves were the likely source from which all modern dogs trace their origins, the demographic history described in this study has fundamental implications for understanding the geographical origin of the dog.
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Early Pleistocene origin and extensive intra-species diversity of the extinct cave lion
- The cave lion is an extinct felid that was widespread across the Holarctic throughout the Late Pleistocene. Its closest extant relative is the lion (Panthera leo), but the timing of the divergence between these two taxa, as well as their taxonomic ranking are contentious. In this study we analyse 31 mitochondrial genome sequences from cave lion individuals that, through a combination of 14C and genetic tip dating, are estimated to be from dates extending well into the mid-Pleistocene. We identified two deeply diverged and well-supported reciprocally monophyletic mitogenome clades in the cave lion, and an additional third distinct lineage represented by a single individual. One of these clades was restricted to Beringia while the other was prevalent across western Eurasia. These observed clade distributions are in line with previous observations that Beringian and European cave lions were morphologically distinct. The divergence dates for these lineages are estimated to be far older than those between extant lions subspecies. By combining our radiocarbon tip-dates with a split time prior that takes into account the most up-to-date fossil stem calibrations, we estimated the mitochondrial DNA divergence between cave lions and lions to be 1.85 Million ya (95% 0.52– 2.91 Mya). Taken together, these results support previous hypotheses that cave lions existed as at least two subspecies during the Pleistocene, and that lions and cave lions were distinct species.
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Size of the lower carnassial in the arctic and the red fox from Late Pleistocene in Belgium compared to other ancient and extant populations
- Lengths, widths, and size proportions (length to width) of the lower carnassial were measured in 45 teeth of the arctic fox and 35 teeth of the red fox from Belgium radiocarbon dated to 46 640–14 120 ka BP. Data the Late Pleistocene foxes from Belgium were compared to 20 ancient and extant populations form Europe, Asia, and North America. The Pleistocene arctic fox from Belgium showed larger carnassial than in all recent samples of this species, whereas the Belgian fossil red foxes were characterized by the carnassial size comparable to that of the recent Siberian red foxes. Both fox species from the Pleistocene of Belgium showed the highest index of the carnassials length to width, which means increase in carnivorous adaptation. We conclude that the higher level of carnivorous specialization reached by the Belgian arctic and red foxes at the end of the Late Pleistocene reflected their scavenging on kills of large carnivores and human hunters (remains of megafauna). Harsh environmental conditions of that period and specific composition of ecosystems led to adapting to a more carnivorous food niche in both foxes.
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Were ancient foxes far more carnivorous than recent ones? Carnassial morphological evidence
- Crown shape variation of the first lower molar in the arctic (Vulpes lagopus) and red foxes (Vulpes vulpes) was analyzed using five groups of morphotypes. Carnassial morphologies were compared between the species and between spatially and temporally distant populations: one Late Pleistocene (n = 45) and seven modern populations of the arctic fox (n = 259), and one Late Pleistocene (n = 35) and eight modern populations of the red fox (n = 606). The dentition of Holocene red foxes had larger morphotype variability than that of arctic foxes. The lower carnassials of the red fox kept have some primitive characters (additional cusps and stylids, complex shape of transverse cristid), whereas the first lower molars of the arctic fox have undergone crown shape simplification, with the occlusal part of the tooth undergoing a more pronounced adaptation to a more carnivorous diet. From the Late Pleistocene of Belgium to the present days, the arctic fox’s crown shape has been simplified and some primitive characters have disappeared. In the red fox chronological changes in the morphology of the lower carnassials were not clearly identified. The phyletic tree based on morphotype carnassial characteristics indicated the distinctiveness of both foxes: in the arctic fox line, the ancient population from Belgium and recent Greenland made separate branches, whereas in the red foxes the ancient population from Belgium was most similar to modern red foxes from Belgium and Italy.
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Could incipient dogs have enhanced differential access to resources among Upper Palaeolithic hunter-gatherers in Europe?
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Genetic turnovers and northern survival during the last glacial maximum in European brown bears
- The current phylogeographic pattern of European brown bears (Ursus arctos) has commonly been explained by postglacial recolonization out of geographically distinct refugia in southern Europe, a pattern well in accordance with the expansion/contraction model. Studies of ancient DNA from brown bear remains have questioned this pattern, but have failed to explain the glacial distribution of mitochondrial brown bear clades and their subsequent expansion across the European continent. We here present 136 new mitochondrial sequences generated from 346 remains from Europe, ranging in age between the Late Pleistocene and historical times. The genetic data show a high Late Pleistocene diversity across the continent and challenge the strict confinement of bears to traditional southern refugia during the last glacial maximum (LGM). The mitochondrial data further suggest a genetic turnover just before this time, as well as a steep demographic decline starting in the mid‐Holocene. Levels of stable nitrogen isotopes from the remains confirm a previously proposed shift toward increasing herbivory around the LGM in Europe. Overall, these results suggest that in addition to climate, anthropogenic impact and inter‐specific competition may have had more important effects on the brown bear's ecology, demography, and genetic structure than previously thought.
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La relation de l’homme au loup pendant le Paléolithique
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Consequences of past climate change and recent human persecution on mitogenomic diversity in the arctic fox
- Ancient DNA provides a powerful means to investigate the timing, rate and extent of population declines caused by extrinsic factors, such as past climate change and human activities. One species probably affected by both these factors is the arctic fox, which had a large distribution during the last glaciation that subsequently contracted at the start of the Holocene. More recently, the arctic fox population in Scandinavia went through a demographic bottleneck owing to human persecution. To investigate the consequences of these processes, we generated mitogenome sequences from a temporal dataset comprising Pleistocene, historical and modern arctic fox samples. We found no evidence that Pleistocene populations in mid-latitude Europe or Russia contributed to the present-day gene pool of the Scandinavian population, suggesting that postglacial climate warming led to local population extinctions. Furthermore, during the twentieth-century bottleneck in Scandinavia, at least half of the mitogenome haplotypes were lost, consistent with a 20-fold reduction in female effective population size. In conclusion, these results suggest that the arctic fox in mainland Western Europe has lost genetic diversity as a result of both past climate change and human persecution. Consequently, it might be particularly vulnerable to the future challenges posed by climate change.
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Le mammouth laineux
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De wolharige mammoet in België
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A landmark-based approach for assessing the reliability of mandibulartooth crowding as a marker of dog domestication
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The evolutionary andphylogeographic history of woollymammoths: a comprehensivemitogenomic analysis
- Near the end of the Pleistocene epoch, populations of the woolly mammoth (Mammuthus primigenius) were distributed across parts of three continents, from western Europe and northern Asia through Beringia to the Atlantic seaboard of North America. Nonetheless, questions about the connectivity and temporal continuity of mammoth populations and species remain unanswered. We use a combination of targeted enrichment and high-throughput sequencing to assemble and interpret a data set of 143 mammoth mitochondrial genomes, sampled from fossils recovered from across their Holarctic range. Our dataset includes 54 previously unpublished mitochondrial genomes and significantly increases the coverage of the Eurasian range of the species. The resulting global phylogeny confirms that the Late Pleistocene mammoth population comprised three distinct mitochondrial lineages that began to diverge ~1.0–2.0 million years ago (Ma). We also find that mammoth mitochondrial lineages were strongly geographically partitioned throughout the Pleistocene. In combination, our genetic results and the pattern of morphological variation in time and space suggest that male-mediated gene flow, rather than large-scale dispersals, was important in the Pleistocene evolutionary history of mammoths.
