Moran Birth-death process is a standard stochastic process that is used to model natural selection in spatially structured populations. A newly occurring mutation that invades a population of residents can either fixate on the whole population or it can go extinct due to random drift. The duration of the process depends not only on the total population size n, but also on the spatial structure of the population. In this work, we consider the Moran process with a single type of individuals who invade and colonize an otherwise empty environment. Mathematically, this corresponds to the setting where the residents have zero reproduction rate, thus they never reproduce. The spatial structure is represented by a graph. We present two main contributions. First, in contrast to the Moran process in which residents do reproduce, we show that the colonization time is always at most a polynomial function of the population size n. Namely, we show that colonization always takes at most [Formula: see text] expected steps, and for each n, we identify the slowest graph where it takes exactly that many steps. Moreover, we establish a stronger bound of roughly [Formula: see text] steps for undirected graphs and an even stronger bound of roughly [Formula: see text] steps for so-called regular graphs. Second, we discuss various complications that one faces when attempting to measure fixation times and colonization times in spatially structured populations, and we propose to measure the real duration of the process, rather than counting the steps of the classic Moran process.
- MeSH
- hustota populace MeSH
- lidé MeSH
- mutace MeSH
- počítačová simulace MeSH
- populační dynamika * MeSH
- selekce (genetika) MeSH
- stochastické procesy MeSH
- výpočetní biologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Synchronous fluctuations in species' abundance are influenced by synchrony in underlying rates of productivity and survival. However, it remains unclear how rate synchrony varies in space and time, contributes to abundance synchrony, and differs among species. Using long-term annual count (number of adults captured), adult survival and productivity (number of juveniles captured per adult) data for breeding land-birds at ringing sites across Europe, we show that synchrony is strongest and largest scale in productivity and weakest and smallest scale in counts. However, counts fluctuate more synchronously with survival than they do with productivity. These patterns hold for species which do not migrate or only migrate within Europe (European-residents) and those migrating to sub-Saharan Africa (subSaharan-migrants), but the periodicity of productivity and survival synchrony is longer in European-residents than in subSaharan-migrants. This suggests that survival and productivity synchrony may interact to weaken abundance fluctuations but are influenced by environmental drivers operating over differing timescales in European-resident and subSaharan-migrant species.
- Klíčová slova
- annual variation, avian ecology, conservation, migratory birds, population abundance, productivity, survival rates,
- MeSH
- hustota populace MeSH
- migrace zvířat * MeSH
- populační dynamika MeSH
- ptáci * fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Evropa MeSH
- subsaharská Afrika MeSH
The European Final Palaeolithic witnessed marked changes in almost all societal domains. Despite a rich body of evidence, our knowledge of human palaeodemographic processes and regional population dynamics still needs to be improved. In this study, we present regionally differentiated population estimates for the Greenland Interstadial 1d-a (GI-1d-a; 14-12.7 ka cal BP) and the Greenland Stadial 1 (GS-1; 12.7-11.6 ka cal BP) for Southern, Western, Northern and Central Europe. The data were obtained by applying the Cologne Protocol, a geostatistical approach for estimating prehistoric population size and density, to a newly compiled dataset of Final Palaeolithic sites. On a large spatio-temporal scale and compared to preceding Upper Palaeolithic phases, areas north of the Alps become the dominant demographic growth area for the first time since the dispersal of anatomically modern humans into Europe. At smaller scales, we observe divergent regional trends, with a conspicuous lack of archaeological evidence appearing in previously occupied areas of central France and Germany. Our study also shows that during the Final Palaeolithic, the climatic cooling of GS-1 coincides with a pronounced population decline in most parts of the study area. An apparent increase in population density occurs only in north-eastern Central Europe and north-eastern Italy. Our estimates suggest that the total population was reduced by half. Similar results, with a relationship between decreasing temperatures and decreasing populations, have already been observed for the late phase of the Gravettian, when populations were reduced to only one third of those estimated for the early phase. Yet, in contrast to the collapse of local populations during the late Gravettian, the increase in population densities in Central Europe during GS-1 indicates population movements eastwards, possibly in response to deteriorating climatic conditions, particularly in western regions during the Younger Dryas.
- MeSH
- archeologie MeSH
- dějiny starověku MeSH
- hustota populace MeSH
- klimatické změny * dějiny MeSH
- lidé MeSH
- populační dynamika * MeSH
- Check Tag
- dějiny starověku MeSH
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- historické články MeSH
- Geografické názvy
- Evropa MeSH
Restricted range size brings about noteworthy genetic consequences that may affect the viability of a population and eventually its extinction. Particularly, the question if an increase in inbreeding can avert the accumulation of genetic load via purging is hotly debated in the conservation genetic field. Insular populations with limited range sizes represent an ideal setup for relating range size to these genetic factors. Leveraging a set of eight differently sized populations of Galápagos mockingbirds (Mimus), we investigated how island size shaped effective population size (Ne), inbreeding and genetic load. We assembled a genome of M. melanotis and genotyped three individuals per population by whole-genome resequencing. Demographic inference showed that the Ne of most populations remained high after the colonisation of the archipelago 1-2 Mya. Ne decline in M. parvulus happened only 10-20 Kya, whereas the critically endangered M. trifasciatus showed a longer history of reduced Ne. Despite these historical fluctuations, the current island size determines Ne in a linear fashion. In contrast, significant inbreeding coefficients, derived from runs of homozygosity, were identified only in the four smallest populations. The index of additive genetic load suggested purging in M. parvulus, where the smallest populations showed the lowest load. By contrast, M. trifasciatus carried the highest genetic load, possibly due to a recent rapid bottleneck. Overall, our study demonstrates a complex effect of demography on inbreeding and genetic load, providing implications in conservation genetics in general and in a conservation project of M. trifasciatus in particular.
- Klíčová slova
- conservation genetics, demographic inference, genetic diversity, genetic load,
- MeSH
- genetická zátěž * MeSH
- genom * MeSH
- genotyp MeSH
- hustota populace MeSH
- inbreeding * MeSH
- ostrovy MeSH
- Passeriformes * genetika MeSH
- populační genetika * MeSH
- zachování přírodních zdrojů MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Ekvádor MeSH
- ostrovy MeSH
Nepal, largely covered by the Himalayan mountains, hosts indigenous populations with distinct linguistic, cultural, and genetic characteristics. Among these populations, the Raute, Nepal's last nomadic hunter-gatherers, offer a unique insight into the genetic and demographic history of Himalayan foragers. Despite strong cultural connections to other regional foragers, the genetic history of this population remains understudied. This study presents newly genotyped genome-wide SNP data of the Raute to explore their genetic isolation, their origins and potential as an older foraging lineage, and their genetic connections to other regional foragers. Our results show that high levels of inbreeding in the Raute indicate recent genetic isolation. Effective population size estimates suggest a dramatic population decline around 50 generations ago. Strong genetic similarity to Nepalese populations of various subsistence styles highlights a dynamic history of genetic interactions prior to isolation, with particular closeness to historical foragers like the Kusunda and Tharu, but excludes an ancient foraging lineage origin. The study underscores the complexity of human population dynamics in the Himalayas, suggesting a history of extensive interaction between foragers and farmers, followed by isolation and demographic decline among the Raute.
- Klíčová slova
- Hunter-gatherers, Nepal, Population Genetics, Raute, Runs of Homozygosity,
- MeSH
- hustota populace MeSH
- jednonukleotidový polymorfismus * MeSH
- lidé MeSH
- populační dynamika MeSH
- populační genetika * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Himálaj MeSH
- Nepál MeSH
Birds, bats and ants are recognised as significant arthropod predators. However, empirical studies reveal inconsistent trends in their relative roles in top-down control across strata. Here, we describe the differences between forest strata in the separate effects of birds, bats and ants on arthropod densities and their cascading effects on plant damage. We implemented a factorial design to exclude vertebrates and ants in both the canopy and understorey. Additionally, we separately excluded birds and bats from the understorey using diurnal and nocturnal exclosures. At the end of the experiments, we collected all arthropods and assessed herbivory damage. Arthropods responded similarly to predator exclusion across forest strata, with a density increase of 81% on trees without vertebrates and 53% without both vertebrates and ants. Additionally, bird exclusion alone led to an 89% increase in arthropod density, while bat exclusion resulted in a 63% increase. Herbivory increased by 42% when vertebrates were excluded and by 35% when both vertebrates and ants were excluded. Bird exclusion alone increased herbivory damage by 28%, while the exclusion of bats showed a detectable but non-significant increase (by 22%). In contrast, ant exclusion had no significant effect on arthropod density or herbivory damage across strata. Our results reveal that the effects of birds and bats on arthropod density and herbivory damage are similar between the forest canopy and understorey in this temperate forest. In addition, ants were not found to be significant predators in our system. Furthermore, birds, bats and ants appeared to exhibit antagonistic relationships in influencing arthropod density. These findings highlight, unprecedentedly, the equal importance of birds and bats in maintaining ecological balance across different strata of a temperate forest.
- Klíčová slova
- arthropod density, forest canopy, forest understorey, herbivory damage, predator exclosures, trophic cascades,
- MeSH
- býložravci MeSH
- Chiroptera * fyziologie MeSH
- členovci * fyziologie MeSH
- Formicidae * fyziologie MeSH
- hustota populace MeSH
- lesy * MeSH
- potravní řetězec MeSH
- predátorské chování MeSH
- ptáci * fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Japonsko MeSH
BACKGROUND: Few animal populations have been studied under the framework of the OCBIL theory, which addresses the ecology and evolution of biodiversity on old climatically buffered infertile landscapes. Available genetic data challenge the low connectivity and high genetic differentiation predicted for isolated tepui-summit vertebrate communities, suggesting potential dispersal among summits. However, the OCBIL theory posits reduced dispersibility, enhanced resilience to habitat fragmentation and inbreeding due to small populations. We tested these hypotheses by conducting the first analytic evaluation of the spatial ecology and population biology of a tepui-summit vertebrate at multiple spatial scales. RESULTS: We used harmonic radar tracking (100 individuals/448 points of contact) and capture-mark-recapture data (596 individuals captured/52 recaptured) to reveal the temporal niche, microhabitat use, population size, and dispersal abilities of the tepui-summit endemic toad Oreophrynella quelchii on Roraima-tepui. Abundance was determined using a closed population model incorporating sources of variation in capture probability. We tested the relative influence of biotic and abiotic variables on distances moved through model selection. Our data indicate that the population size of O. quelchii is remarkably large (ca. 12 million individuals), with strong seasonal demographic fluctuations. Ecology and observed limited spatial movements challenge the likelihood of active dispersal among tepui tops in this species. Our results are counter to those predicted by the available genetic data but support two hypotheses of the OCBIL theory: reduced dispersibility and enhanced resilience. However, they do not support the expectation of a small refugial population size. CONCLUSION: We postulate that the insular, hostile tepui-summit environment tends to produce robust demographic populations, likely to buffer stochastic adverse environmental effects, rather than diversity, as observed in much younger post-Pleistocene Neotropical landscapes. Our results draw attention to the value of faunal studies using an OCBIL framework to better understand the ecology and evolution of this unique biota worldwide.
- Klíčová slova
- Animal movement, Capture-mark-recapture, Climate change, Dispersal abilities, Environmental factors, Tepui summit,
- MeSH
- ekosystém * MeSH
- hustota populace MeSH
- populační dynamika MeSH
- rozšíření zvířat MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Background: While the influence of landscape and microclimatic conditions on tick populations is well-documented, there remains a gap in more specific data regarding their relationship to rewilding efforts with large herbivore activity. Objective: This pilot study, spanning from 2019 to 2021, explores the effects of naturalistic grazing by large semi-wild ungulates on tick abundance in the Milovice Reserve, Czechia. Methods: Tick collection was observed using flagging techniques at two distinct sites of rewilding area: one grazed, actively utilized by animals involved in the rewilding project, and one ungrazed, left fallow in neighboring areas utilized only by wild animals. Transects, each measuring 150 m in length and 5 m in width (750 m2), were established at these two sampling locations from March to September between 2019 and 2021. To minimize potential bias resulting from tick movement, a 300 m buffer zone separated the two sites. Data analysis employed a generalized estimating equations (GEE) model with negative binomial regression. The study assessed potential variations in tick abundance between selected transects, considering factors such as plant cover seasonality, temperature, and humidity. Results: During the collection periods, we gathered 586 live ticks, with 20% found in grazed areas and 80% in ungrazed areas. Notably, tick abundance was significantly higher in ungrazed areas. Peaks in tick abundance occurred in both grazed and ungrazed areas during spring, particularly in April. However, tick numbers declined more rapidly in grazed areas. Microclimatic variables like temperature and humidity did not significantly impact tick abundance compared to landscape management and seasonal factors. Conclusion: Rewilding efforts, particularly natural grazing by large ungulates, influence tick abundance and distribution. This study provides empirical data on tick ecology in rewilded areas, highlighting the importance of landscape management and environmental factors in tick management and conservation. Trophic rewilding plays a crucial role in shaping ecosystems and tick population dynamics in transformed landscapes.
- Klíčová slova
- ecosystem, ecto-parasites, landscape management, large ungulates, seasonality, ticks,
- MeSH
- býložravci * MeSH
- ekosystém MeSH
- hustota populace MeSH
- klíště * fyziologie MeSH
- pilotní projekty MeSH
- roční období MeSH
- zachování přírodních zdrojů MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
Understanding how large carnivores utilize space is crucial for management planning in human-dominated landscape and enhances the accuracy of population size estimates. However, Eurasian lynx display a large inter-population variation in the size of home ranges across their European range which makes extrapolation to broader areas of a species distribution problematic. This study evaluates variations in home range size for 35 Eurasian lynx in the Western Carpathians during 2011-2022 based on GPS telemetry and explains how intrinsic and environmental factors shape lynx spatial behaviour when facing anthropogenic pressure. The average annual home range size of lynx ranged from 283 (± 42 SE) to 360 (± 60 SE) km2 for males and from 148 (± 50 SE) to 190 (± 70 SE) km2 for females, depending on home range estimator (95% MCP, KDE and AKDE). Females with kittens had smaller annual and summer home ranges compared to non-reproducing females and subadults had smaller home ranges compared to adults. Lynx home range size was explained by availability of roe deer, except for summer, when alternative prey was likely available. We also found clear evidence of human-induced changes in lynx home range size, in particular, forest cover significantly decreased the home range size of male lynx during summer while road density led to an expansion of both annual and summer lynx home ranges. Lynx exhibited consistent fidelity to their home ranges throughout consecutive seasons, showing no seasonal variations. Strong territoriality was observed among competing males maintaining relatively low home range overlaps and considerable distances between centres of activity. The most pronounced tendency for association was observed between males and females, maintaining relatively close proximity year-round. The insights into lynx spatial requirements provided by our study will greatly enhance the accuracy of population size estimates and effectiveness of mitigation measures across the Western Carpathians.
- Klíčová slova
- GPS telemetry, Home range, Large carnivore, Temperate forests,
- MeSH
- ekosystém MeSH
- hustota populace MeSH
- Lynx * fyziologie MeSH
- roční období MeSH
- teritoriální chování * fyziologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The adoption of the European Green Deal will limit acaricide use in high value crops like raspberry, to be replaced by biological control and other alternative strategies. More basic knowledge on mites in such crops is then necessary, like species, density, and their role as vectors of plant diseases. This study had four aims, focusing on raspberry leaves at northern altitude: (1) identify mite species; (2) study mite population densities; (3) investigate mite intra-plant distribution; (4) investigate co-occurrence of phytophagous mites, raspberry leaf blotch disorder and raspberry leaf blotch virus (RLBV). Four sites in south-eastern Norway were sampled five times. Floricanes from different parts of the sites were collected, taking one leaf from each of the upper, middle, and bottom zones of the cane. Mites were extracted with a washing technique and processed for species identification and RLBV detection. Mites and leaves were tested for RLBV by reverse transcription polymerase chain reaction (RT-PCR) with virus-specific primers. Phytophagous mites, Phyllocoptes gracilis, Tetranychus urticae, and Neotetranychus rubi, and predatory mites, Anystis baccarum and Typhlodromus (Typhlodromus) pyri were identified. All phytophagous mites in cultivated raspberry preferred the upper zone of floricanes, while in non-cultivated raspberry, they preferred the middle zone. The presence of phytophagous mites did not lead to raspberry leaf blotch disorder during this study. RLBV was detected in 1.3% of the sampled plants, none of them with leaf blotch symptoms, and in 4.3% of P. gracilis samples, and in some spider mite samples, implying that Tetranychids could also be vectors of RLBV.
- Klíčová slova
- Emaravirus idaeobati, Anystidae, Eriophyidae, Generalist predatory mites, Raspberry leaf blotch virus, Tetranychidae,
- MeSH
- hustota populace * MeSH
- listy rostlin MeSH
- nemoci rostlin parazitologie MeSH
- rozšíření zvířat MeSH
- roztoči * fyziologie MeSH
- Rubus * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Norsko MeSH