extant population
Recently Published Documents


TOTAL DOCUMENTS

35
(FIVE YEARS 15)

H-INDEX

7
(FIVE YEARS 1)

2021 ◽  
Vol 34 (2) ◽  
pp. 187-205
Author(s):  
Catherine R. Peters

In this article, I elaborate on Lisa Lowe’s “intimacies as method” by examining the case of 198 Chinese men conscripted to Trinidad in 1806. I argue that tracing Chinese migration to the Caribbean in the early nineteenth century demonstrates that the British empire began to imagine new hierarchies of unfreedom for people of Asian and African descent before the abolition of chattel slavery. British imperial actors hoped that Chinese men would assume a mediating function between white planters and the extant population of colour in Trinidad. This vision was predicated on the assumption that the migrants would partner with women of colour to form heterosexual intimacies while also refraining from other forms of socio-political contact with Afro-Trinidadians. Lowe’s intimacies as method guides my navigation of the imperial archive and, in particular, compels me to think relationally about differentially colonized and racialized sub jects in early nineteenth-century Trinidad, both as they were positioned in the colony and as they refused these stereotypes, brokering their own transactions and collaborations.


Author(s):  
Carina Motta ◽  
Justin Luong ◽  
Katja Seltmann

The reintroduction of endangered plant species is an essential conservation tool. Reintroductions can fail to create resilient, self-sustaining populations due to a poor understanding of environmental factors that limit or promote plant success. Biotic factors, specifically plant-arthropod interactions, have been shown to affect the establishment of endangered plant populations. Lupinus nipomensis (Nipomo Mesa lupine) is a state of California (California Rare Plant Rank: 1B.1) and federally (65 FR 14888) endangered endemic plant with only one extant population located along the central California coast. How arthropods positively or negatively interact with L. nipomensis is not well known and more information could aid conservation efforts. We conducted arthropod surveys of the entire L. nipomensis extant population in spring 2017. Observed arthropods present on L. nipomensis included 17 families, with a majority of individuals belonging to Thripidae. We did not detect any obvious pollinators of L. nipomensis, providing support for previous studies suggesting this lupine is capable of self-pollinating, and observed several arthropod genera that could potentially impact the reproductive success of L. nipomensis via incidental pollination or plant predation.


2021 ◽  
Author(s):  
Geneva Carla S. Chavez ◽  
Vachel Gay Paller ◽  
Renee P. Lorica ◽  
Judeline Dimalibot

Abstract The expansion of ecotourism and forest encroachment in the Philippines creates a high-risk interface where human-macaque interactions occur at rates were cross-species transmission of disease may occur more frequently than previously known. Puerto Princesa Subterranean River National Park is a prime tourist destination in the country where long-tailed macaques live as commensals to humans. This study was conducted to assess zoonotic enteroparasites of Macaca fascicularis to determine their prevalence in the extant population. Fecal samples were collected during two-kilometer transect walks whilst opportunistic sampling was also conducted in the park proper where there is high tourist traffic. Among protozoans, Entamoeba coli showed the highest prevalence (34.29%), followed by Entamoeba spp. and Iodamoeba butschlii (31.43%), Endolimax nana (28.57%), Blastocystis sp. (22.86%), Chilomastix mesnili Entamoeba polecki (20%), and Giardia intestinalis (8.57%). From the helminth group, hookworm larva was the most prevalent (40%), followed by hookworm/strongylids ova (34.29%), Strongyloides sp. larva (28.57%), T. trichiura (20%), Ascaris sp. (11.43%), and lastly, Hymenolepis nana and Enterobius vermicularis (2.86%). This study demonstrates the importance of long-tailed macaques in the transmission of enteroparasites in an environment where there is frequent contact between nonhuman primates and people.


Author(s):  
Yasmin Foster ◽  
Ludovic Dutoit ◽  
Stefanie Grosser ◽  
Nicolas Dussex ◽  
Brodie J Foster ◽  
...  

Abstract Events of inbreeding are inevitable in critically endangered species. Reduced population sizes and unique life-history traits can increase the severity of inbreeding, leading to declines in fitness and increased risk of extinction. Here, we investigate levels of inbreeding in a critically endangered flightless parrot, the kākāpō (Strigops habroptilus), wherein a highly inbred island population and one individual from the mainland of New Zealand founded the entire extant population. Genotyping-by-sequencing (GBS), and a genotype calling approach using a chromosome-level genome assembly, identified a filtered set of 12,241 single-nucleotide polymorphisms (SNPs) among 161 kākāpō, which together encompass the total genetic potential of the extant population. Multiple molecular-based estimates of inbreeding were compared, including genome-wide estimates of heterozygosity (FH), the diagonal elements of a genomic-relatedness matrix (FGRM), and runs of homozygosity (RoH, FRoH). In addition, we compared levels of inbreeding in chicks from a recent breeding season to examine if inbreeding is associated with offspring survival. The density of SNPs generated with GBS was sufficient to identify chromosomes that were largely homozygous with RoH distributed in similar patterns to other inbred species. Measures of inbreeding were largely correlated and differed significantly between descendants of the two founding populations. However, neither inbreeding nor ancestry was found to be associated with reduced survivorship in chicks, owing to unexpected mortality in chicks exhibiting low levels of inbreeding. Our study highlights important considerations for estimating inbreeding in critically endangered species, such as the impacts of small population sizes and admixture between diverse lineages.


PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0253631
Author(s):  
Gentile Francesco Ficetola ◽  
Iolanda Silva-Rocha ◽  
Miguel A. Carretero ◽  
Leonardo Vignoli ◽  
Roberto Sacchi ◽  
...  

The Aeolian wall lizard Podarcis raffonei is an island endemic that survives only on three tiny islets, and on the Capo Grosso peninsula of the Vulcano island, thus is among the European vertebrates with the smallest range and one of the most threatened by extinction. This species is declining due to competition and hybridization with the non-native lizard Podarcis siculus, but a regular monitoring program is lacking. Here we assessed the size and status of the Capo Grosso population of P. raffonei on Vulcano. In September 2015 we captured 30 individuals showing the typical brown phenotype of P. raffonei, while one single male showed a green phenotype, apparently intermediate between P. raffonei and the non-native Podarcis siculus. In May 2017, only 47% of 131 individuals showed the typical brown phenotype (P. raffonei-like) and 53% showed the green phenotype (P. siculus-like). Based on N-mixture models and removal sampling the estimated size of the Capo Grosso population was of 800–1300 individuals in 2017, being similar to 2015; available data suggest that the total range of the species could be as small as 2 ha. The frequency of individuals with the typical P. raffonei phenotype dramatically dropped between two samplings with a parallel increase of individuals displaying the green phenotype. Observation on outdoor captive-bred individuals demonstrates plasticity for colouration in P. raffonei individuals from Capo Grosso, with several individuals showing the typical brown pattern in September 2017 and a green pattern in March 2021. Non-exclusive hypotheses, including hybridization with P. siculus and plasticity in colour pattern of P. raffonei, are discussed to explain the phenotypic shifts of the P. raffonei population of Capo Grosso. While genomic evidence is required to reach conclusions and investigate eventual hybridization, it is urgent to undertake a programme for the monitoring and management of this lizard.


2021 ◽  
Vol 53 (2) ◽  
pp. 537-574
Author(s):  
Romain Abraham ◽  
Jean-François Delmas

AbstractWe consider a model of a stationary population with random size given by a continuous-state branching process with immigration with a quadratic branching mechanism. We give an exact elementary simulation procedure for the genealogical tree of n individuals randomly chosen among the extant population at a given time. Then we prove the convergence of the renormalized total length of this genealogical tree as n goes to infinity; see also Pfaffelhuber, Wakolbinger and Weisshaupt (2011) in the context of a constant-size population. The limit appears already in Bi and Delmas (2016) but with a different approximation of the full genealogical tree. The proof is based on the ancestral process of the extant population at a fixed time, which was defined by Aldous and Popovic (2005) in the critical case.


Author(s):  
M. Caputo ◽  
M. A. Amador ◽  
A. Sala ◽  
A. Riveiro dos Santos ◽  
S. Santos ◽  
...  
Keyword(s):  

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9763
Author(s):  
Mizraim Olivares-Miranda ◽  
Vance T. Vredenburg ◽  
Julio C. García-Sánchez ◽  
Allison Q. Byrne ◽  
Erica B. Rosenblum ◽  
...  

The fungal pathogen Batrachochytrium dendrobatidis (Bd) is implicated in global mass die-offs and declines in amphibians. In Mesoamerica, the Bd epidemic wave hypothesis is supported by detection of Bd in historic museum specimens collected over the last century, yet the timing and impact of the early stages of the wave remain poorly understood. Chiropterotriton magnipes, the only obligate troglodytic Neotropical salamander, was abundant in its small range in the decade following its description in 1965, but subsequently disappeared from known localities and was not seen for 34 years. Its decline is roughly coincident with that of other populations of Neotropical salamanders associated with the invasion and spread of Bd. To determine the presence and infection intensity of Bd on C. magnipes and sympatric amphibian species (which are also Bd hosts), we used a noninvasive sampling technique and qPCR assay to detect Bd on museum specimens of C. magnipes collected from 1952 to 2012, and from extant populations of C. magnipes and sympatric species of amphibians. We also tested for the presence of the recently discovered Batrachochytrium salamandivorans (Bsal), another fungal chytridiomycete pathogen of salamanders, using a similar technique specific for Bsal. We did not detect Bd in populations of C. magnipes before 1969, while Bd was detected at low to moderate prevalence just prior to and during declines. This pattern is consistent with Bd-caused epizootics followed by host declines and extirpations described in other hosts. We did not detect Bsal in any extant population of C. magnipes. We obtained one of the earliest positive records of the fungus to date in Latin America, providing additional historical evidence consistent with the Bd epidemic wave hypothesis. Genotyping results show that at least one population is currently infected with the Global Panzootic Lineage of Bd, but our genotyping of the historical positive samples was unsuccessful. The lack of large samples from some years and the difficulty in genotyping historical Bd samples illustrate some of the difficulties inherent in assigning causality to historical amphibian declines. These data also provide an important historical baseline for actions to preserve the few known remaining populations of C. magnipes.


2020 ◽  
Vol 12 (11) ◽  
pp. 2139-2152
Author(s):  
Lukas Weilguny ◽  
Christos Vlachos ◽  
Divya Selvaraju ◽  
Robert Kofler

Abstract The P-element, one of the best understood eukaryotic transposable elements, spread in natural Drosophila melanogaster populations in the last century. It invaded American populations first and later spread to the Old World. Inferring this invasion route was made possible by a unique resource available in D. melanogaster: Many strains sampled from different locations over the course of the last century. Here, we test the hypothesis that the invasion route of the P-element may be reconstructed from extant population samples using internal deletions (IDs) as markers. These IDs arise at a high rate when DNA transposons, such as the P-element, are active. We suggest that inferring invasion routes is possible as: 1) the fraction of IDs increases in successively invaded populations, which also explains the striking differences in the ID content between American and European populations, and 2) successively invaded populations end up with similar sets of IDs. This approach allowed us to reconstruct the invasion route of the P-element with reasonable accuracy. Our approach also sheds light on the unknown timing of the invasion in African populations: We suggest that African populations were invaded after American but before European populations. Simulations of TE invasions in spatially distributed populations confirm that IDs may allow us to infer invasion routes. Our approach might be applicable to other DNA transposons in different host species.


2020 ◽  
Vol 30 (30) ◽  
pp. 37-47
Author(s):  
Abdelmadjid Chelli ◽  
Riadh Moulaï ◽  
Abdelhadi Djemai

This paper reports a pioneer study dealing with the impact of dam construction on Odonata communities, because no similar study has been undertaken in Algeria and the consequences of this artificialization on the Odonata assemblages have rarely been studied elsewhere. The main purpose of this study was to determine if the Tichi Haf dam is really having a negative effect on the Odonata communities living on the Boussellam watercourse, as there has hitherto been a lack of knowledge about its odonatofauna and aquatic microinvertebrates. This study showed that changes due to the construction of this dam, involving riparian vegetation, bank aspect and water parameters, affected the Odonata assemblages inhabiting both sides of the dam wall. The richness and abundance of dragonflies and damselflies found upstream from the dam is quite different from those found downstream from the dam. The survey also identified four new species for the Bejaia region. Among these, we report on the rediscovery of the critically endangered (EN) Calopteryx exul in Algeria, recorded in the nineteenth century and deemed to have been extinct after an absence of more than a century. The presence of an extant population C. exul in this location does not correspond to any historical locality reported for this species.


Sign in / Sign up

Export Citation Format

Share Document