Black‐headed penduline tit (Remiz macronyx) is a poorly known bird species mainly distributed in Iran, Turkmenistan, and Kazakhstan. The distribution of black‐headed penduline tit is disjointed and ...fragmented, and it occurs only along lakes or rivers surrounded by extensive reedbeds. Four subspecies of R. macronyx have been recognized (macronyx, neglectus, nigricans, and ssaposhnikowi). The ssaposhnikowi subspecies was previously known to occur only around lakes in southeastern Kazakhstan. In this study, we reported the first confirmed breeding record of R. m. ssaposhnikowi in the Nalati wetland, Ili, Xinjiang, China, extending the distribution range of the black‐headed penduline tit by 350 km to the east. We also obtained new information about the morphology and breeding behavior of R. m. ssaposhnikowi, which can be useful for the taxonomy of penduline tits, especially in distinguishing black‐headed penduline tits from Eurasian penduline tits (R. pendulinus).
This study is the first to confirm black‐headed penduline tits (Remiz macronyx ssaposhnikowi) breeding in the Nalati wetland, Ili Prefecture, Xinjiang, China. We also obtained new information about the morphology and breeding behavior and photographed their delicate nests for the first time.
Speciation with gene flow is an alternative to the nascence of new taxa in strict allopatric separation. Indeed, many taxa have parapatric distributions at present. It is often unclear if these are ...secondary contacts, e.g. caused by past glaciation cycles or the manifestation of speciation with gene flow, which hampers our understanding of how different forces drive diversification. Here we studied genetic, phenotypic and ecological aspects of divergence in a pair of incipient shorebird species, the Kentish (Charadrius alexandrinus) and the White-faced Plovers (C. dealbatus), shorebirds with parapatric breeding ranges along the Chinese coast. We assessed divergence based on molecular markers with different modes of inheritance and quantified phenotypic and ecological divergence in aspects of morphometric, dietary and climatic niches.
Our integrative analyses revealed small to moderate levels of genetic and phenotypic distinctiveness with symmetric gene flow across the contact area at the Chinese coast. The two species diverged approximately half a million years ago in dynamic isolation with secondary contact occurring due to cycling sea level changes between the Eastern and Southern China Sea in the mid-late Pleistocene. We found evidence of character displacement and ecological niche differentiation between the two species, invoking the role of selection in facilitating divergence despite gene flow.
These findings imply that ecology can indeed counter gene flow through divergent selection and thus contributes to incipient speciation in these plovers. Furthermore, our study highlights the importance of using integrative datasets to reveal the evolutionary history and assist the inference of mechanisms of speciation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Protected areas provide essential habitats for wildlife by conserving natural and semi‐natural habitats and reducing human disturbance. However, whether breeding birds vulnerable to nest predation ...can benefit from strict land management in the protected area is unclear. Here, we compare the nesting performance of two groups of a ground‐nesting shorebird, the Kentish plover (Charadrius alexandrinus), in the protected area (Liaohekou Natural Reserve, hereinafter PA), and the control non‐protected area (non‐PA) around the Liaohekou Natural Reserve, in the north of the Yellow Sea, China, and identify which environmental factors, such as nesting habitat and nest materials, influence the daily nest survival rate (DSR). We found similar nesting habitats in both study areas, dominated by bare land or Suaeda salsa grassland. However, DSR was lower in PA (0.91 ± 0.01) than in non‐PA (0.97 ± 0.01). Kentish plovers nesting in areas with vegetation cover experienced lower DSR than in bare lands in both areas, and nests built with materials of S. salsa sticks had the lowest DSR in the bare land. Data from infrared cameras confirmed relatively higher predator abundances and nest predation rates by nocturnal mammals, such as Eurasian badgers (Meles meles), in PA than in non‐PA, and this pattern was especially evident for plover nests located in S. salsa grassland. Our results suggest that Liaohekou Natural Reserve protected area may not necessarily provide safe nesting sites for Kentish plovers due to the abundance of generalist mammal nest predators. However, the PA includes about 80% of the nests from both locations. This means the contribution of the total number of successful nests continues to be much higher within PA, with the benefit for the species that this brings in terms of conservation. The variation and mechanisms underlying differences in the nest predator communities of PA and non‐PA deserve further study.
The daily nest survival rate of Kentish plover nesting within the protected areas was lower than that outside the protected areas. Kentish plovers nesting in areas with vegetation cover dominated by Suaeda salsa experienced lower DSR than in bare lands. Higher predator densities of nocturnal mammals in the protected areas increased the nest predation rate of Kentish plovers.
Mercury pollution is a global problem and of particular concern in high emissions areas, such as China. We studied the migratory Kentish Plover,
Charadrius alexandrinus,
which breeds in coastal ...northern/central China and the inland Qinghai Lake, and the White-faced Plover
C. dealbatus
, a year-round resident of coastal southern China. We measured total mercury (THg) concentrations in feather and blood samples of breeding females. We expected low levels at the remote Qinghai Lake, but we found instead that feather THg concentrations were highest there (3.89 ± 1.53 SD μg/g DW n = 34; compared to 1.29 ± 0.61 μg/g of Kentish Plover elsewhere n = 35 and 2.08 ± 1.45 μg/g for White-faced Plover n = 56), a result is consistent over 2 years. When including only coastal populations in the analysis, there were no differences in THg concentrations between the two species, although White-faced Plover had more variation. Feather THg concentrations for the coastal populations are similar to other studies on plovers and sandpipers globally, with most birds under the threshold of adverse effects (3 μg/g, an estimate that itself may be too low). Nevertheless, the Qinghai Kentish Plover population has mean feather concentrations above this threshold, indicating high exposure during the nonbreeding season, and some individuals have extreme values (e.g., a bird with a blood level of 7.63 μg/g DW from Zhanjiang, south China), so further research and monitoring are needed.
Giant panda behaviour recognition using images Swarup, Pranjal; Chen, Peng; Hou, Rong ...
Global ecology and conservation,
April 2021, 2021-04-00, 2021-04-01, Letnik:
26
Journal Article
Recenzirano
Odprti dostop
Monitoring giant panda (Ailuropoda melanoleuca) behaviour is critical for their conservation and understanding their health conditions. Currently, captive giant panda behaviour is usually monitored ...by their caregivers. In previous studies, researchers observed panda behaviours for short time spans over a period. However, both caregivers and researchers cannot monitor them 24-h using traditional methods of observation. In other words, animal behaviour data are difficult to collect over long periods and are prone to errors when recorded manually. Some researchers have used wearable devices such as accelerometer ear tags and collar-mounted units with a global position system (GPS) receiver and contactless devices such as depth cameras and video cameras for understanding behaviour of other animals such as primates and American white pelicans. However, the giant panda, an icon of endangered species conservation, is almost completely neglected in these studies. To monitor giant panda behaviour effectively, a fully automated giant panda behaviour recognition method based on Faster R–CNN and two modified ResNet was created. The Faster R–CNN network was able to detect panda bodies and panda faces in images. One of the modified ResNet was trained to classify their behaviour into five classes, walking, sitting, resting, climbing, and eating and the other to recognise whether the panda’s eyes and mouth were opened or closed. Experiments were conducted on 10,804 images collected from over 218 pandas in various environments and illumination conditions. The experimental results were very encouraging and achieved an overall accuracy of 90% for the five panda behaviours and an overall accuracy of 84% for the subtle panda facial motions. The proposed method provides an effective way to monitor giant panda behaviour in captivity.
Understanding how incipient species are maintained with gene flow is a fundamental question in evolutionary biology. Whole genome sequencing of multiple individuals holds great potential to ...illustrate patterns of genomic differentiation as well as the associated evolutionary histories. Kentish (
Charadrius alexandrinus
) and the white-faced (
C. dealbatus
) plovers, which differ in their phenotype, ecology and behavior, are two incipient species and parapatrically distributed in East Asia. Previous studies show evidence of genetic diversification with gene flow between the two plovers. Under this scenario, it is of great importance to explore the patterns of divergence at the genomic level and to determine whether specific regions are involved in reproductive isolation and local adaptation. Here we present the first population genomic analysis of the two incipient species based on the
de novo
Kentish plover reference genome and resequenced populations. We show that the two plover lineages are distinct in both nuclear and mitochondrial genomes. Using model-based coalescence analysis, we found that population sizes of Kentish plover increased whereas white-faced plovers declined during the Last Glaciation Period. Moreover, the two plovers diverged allopatrically, with gene flow occurring after secondary contact. This has resulted in low levels of genome-wide differentiation, although we found evidence of a few highly differentiated genomic regions in both the autosomes and the Z-chromosome. This study illustrates that incipient shorebird species with gene flow after secondary contact can exhibit discrete divergence at specific genomic regions and provides basis to further exploration on the genetic basis of relevant phenotypic traits.
When individuals breed more than once, parents are faced with the choice of whether to re-mate with their old partner or divorce and select a new mate. Evolutionary theory predicts that, following ...successful reproduction with a given partner, that partner should be retained for future reproduction. However, recent work in a polygamous bird, has instead indicated that successful parents divorced more often than failed breeders (Halimubieke et al. in Ecol Evol 9:10734-10745, 2019), because one parent can benefit by mating with a new partner and reproducing shortly after divorce. Here we investigate whether successful breeding predicts divorce using data from 14 well-monitored populations of plovers (Charadrius spp.). We show that successful nesting leads to divorce, whereas nest failure leads to retention of the mate for follow-up breeding. Plovers that divorced their partners and simultaneously deserted their broods produced more offspring within a season than parents that retained their mate. Our work provides a counterpoint to theoretical expectations that divorce is triggered by low reproductive success, and supports adaptive explanations of divorce as a strategy to improve individual reproductive success. In addition, we show that temperature may modulate these costs and benefits, and contribute to dynamic variation in patterns of divorce across plover breeding systems.
Global biodiversity is facing serious threats. However, knowledge of the genomic consequences of recent rapid population declines of wild organisms is limited. Do populations experiencing recent ...rapid population decline have the same genomic status as wild populations that experience long-term declines? Yellow-breasted Bunting (Emberiza aureola) is a critically endangered species that has been experiencing a recent rapid population decline. To answer the question, we assembled and annotated the whole genome of Yellow-breasted Bunting. Furthermore, we found high genetic diversity, low linkage disequilibrium, and low proportion of long runs of homozygosity in Yellow-breasted Bunting, suggesting that the populations following recent rapid declines have different genomic statuses from the population that experienced long-term population decline.
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•A bird species harbors high genetic diversity following a rapid population decline•Inbreeding levels are low, too•However, the species’ genome has potentially lethal mutations•Rapid population decline of Yellow-breasted Bunting likely began 147 generations ago
Wildlife genetics; Biological sciences; Omics; Genomics
Abstract
Background
The allocation of resources between offspring size and number is a central question of life-history theory. Although several studies have tested the existence of this trade-off, ...few studies have investigated how environmental variation influences the allocation of resources to offspring size and offspring number. Additionally, the relationship between population dynamics and the offspring size and number allocation is far less understood.
Methods
We investigate whether resource allocation between egg size and clutch size is influenced by the ambient temperature and whether it may be related to apparent nest survival rate. We measured 1548 eggs from 541 nests of two closely related shorebird species, the Kentish Plover (
Charadrius alexandrinus
) and the White-faced Plover (
C. dealbatus
) in China, in four populations that exhibit contrasting ambient environments. We weighed females, monitored nest survival, and calculated the variance of ambient temperature.
Results
Although we found that egg size and clutch size were all different between the four breeding populations, the reproductive investment (i.e. total clutch volume) was similar between populations. We also found that populations with a high survival rate had relatively larger eggs and a smaller clutch than populations with a low nest survival rate. The latter result is in line with a conservative/diversified bet-hedging strategy.
Conclusions
Our findings suggest that plovers may increasing fitness by investing fewer, larger or many, small according local nest survival rate to make a similar investment in reproduction, and thereby may have an impact on population demography.
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