Conservation genomics analysis reveals recent population decline and possible causes in bumblebee Bombus opulentus

Bumblebees are a genus of pollinators(Bombus)that play important roles in natural ecosystem and agricultural production.Several bumblebee species have been recorded as under population decline,and the proportion of species experiencing popula-tion decline within subgenus Thoracobombus is higher than average.Bombus opulentus is 1 species in Thoracobombus,but little is known about its recent population dynamics.Here,we employed conservation genomics methods to investigate the population dynam-ics of B.opulentus during the recent past and identify the likely environmental factors that may cause population decline.Firstly,we placed the scaffold-level of B.opulentus ref-erence genome sequence onto chromosome-level using Hi-C technique.Then,based on this reference genome and whole-genome resequencing data for 51 B.opulentus samples,we reconstructed the population structure and effective population size(Ne)trajectories of B.opulentus and identified genes that were under positive selection.Our results revealed that the collected B.opulentus samples could be divided into 2 populations,and 1 of them experienced a recent population decline;the declining population also exhibited lower ge-netic diversity and higher inbreeding levels.Genes related to high-temperature tolerance,immune response,and detoxication showed signals of positive selection in the declining population,suggesting that climate warming and pathogen/pesticide exposures may con-tribute to the decline of this B.opulentus population.Taken together,our study provided insights into the demography of B.opulentus populations and highlighted that popula-tions of the same bumblebee species could have contrasting Ne trajectories and population decline could be caused by a combination of various stressors.

Investigation of Habitats and Causes of Population Decline of Euonymus sanguineus in Tibet

Tibet is one of the core distribution areas of the Chinese endemic plant Euonymus sanguineus,but the population decline is obvious. In order to protect and develop the plant resources in Tibet rationally,the ecological environment and growth conditions in Milin County,Nyingchi City,Tibet were investigated by means of sampling method in order to provide the theoretical basis for the protection,introduction,breeding and cultivation of E. sanguineus. The results were as follows:( i) The population quantity of E. sanguineus was too small and the survival area was too small,which seriously affected the interspecific mating,seed development and regeneration,and greatly reduced the genetic diversity within the population;( ii) The dry and hot river valley climate and human and animal activities inhibited the seed germination and seedling growth of E. sanguineus,resulting in very low survival rate of seedlings,and hindering the population expansion of E. sanguineus;( iii) The distribution area is located in the Yarlung Tsangpo river valley,and the natural habitat fragmentation has affected the interspecific gene exchange,resulting in the low seed bearing capacity and germination rate of E. sanguineus,which is the direct cause of the population decline of E. sanguineus;( iv) The litterfall of E. sanguineus had autotoxicity,which inhibited the growth of seedlings under the forest,caused slow natural regeneration of the population,and then caused the population of E. sanguineus to be unable to spread and develop.

Importance of Stewards and Other Protection Efforts for Conservation of Red Knots (Calidris canutus rufa) and Other Shorebirds on Delaware Bay, New Jersey

Understanding the factors that contribute to population stability in long-distance migrant birds is increasingly important, particularly given global climate change, sea level rise, and loss or disturbance at essential habitats. While the populations of most shorebirds are declining worldwide, those that migrate through Delaware Bay, New Jersey and Delaware, are declining at the most rapid rate despite conservation efforts. In this paper, we 1) provide background information on population declines of red knots (Calidris canutus rufa) using Delaware Bay, threats to their foraging, and efforts to reduce threats, 2) summarize briefly our studies of the effects of human activities on knots and other shorebirds, 3) present data on management efforts to protect knots and other shorebirds from the activities of people, and 4) discuss the efficacy of such efforts (usually referred to as “decreasing the effect of human disturbances”). The Shorebird Project on Delaware Bay is over 25 years old and provides long-term data to help assess the status of shorebird numbers, particularly for red knot, as well as the density of horseshoe crabs (Limulus polyphemus) and their eggs. Red knots have continued to decline even more precipitously in the last few years, presenting cause for concern. Protective efforts have been successful in reducing human disruption on the N.J. Delaware Bay beaches, but the lack of uniformity in implementation across the New Jersey side, and across the whole Bay have hampered further improvements. Implementation of signs, fencing, and stewards on some beaches significantly enhanced the use of these beaches by red knots, determined by examining the use of beaches pre- and post-implementation. Implementation of fencing and stewards had the greatest effect. From 1986 to 2018, there was a significant shift in the percent of Delaware Bay red knots using the NJ side, where protection efforts had been implemented on many of the beaches. Merely restricting access (without fencing or other efforts) did not result in more knots using the beaches post-restriction. This is the first paper that clearly shows the protective effects of having beach stewards. We discuss the long-term needs for continued management of Delaware Bay beaches, and other beaches coastwide, and of determining the causes of population declines of red knots.

Welfare for the Aged in Nigeria,a Sustenance for the Declining Older Population and Aged Male in Nigeria

A buttress on the need for welfare program in Nigeria and the important obligation to consider the Economics’and CIA’s contextual position for the dependency ratios,both total and elderly dependency ratio alongside the consideration of the age structure and demography statistics of Nigeria relatively to other economies,particularly as an elixir for the declining older population in Nigeria and the aged male contraction in the nation.Although,older female population is higher in every country as obtainable globally,the Nigerian case is that of drastic contraction in both aged male and older population generally.Therefore,the submission is that the government has to consider the total dependency ratio to the elderly dependency ratio,which is all-encompassing in order to cater for the declining older population and to appropriate the requisite welfare cum benefits programs in the nation.

Status and distribution changes of the endangered Green Peafowl (Pavo muticus) in China over the past three decades (1990s-2017)

Background： Understanding the changes in population dynamics, including demographics, distribution and threats is essential for species status assessing.The endangered Green Peafowl （Povo muticus） has experienced sharp population declines and d stribution range diminishing both in China and Southeast Asia. Field population surveys have not been conducted in China since the 1990s, which hindered conservation planning and decision-making.Methods： With interview and line transects methods, we figured out the population and distribution changes of Green Peafowl across its historical ranges over the past three decades in China during 2014-2017.Results： The Green Peafowl once habituated in 54 counties in China. Nearly 60% of the distribution counties were lost in the past three decades, with the left 22 counties distributed in central, southern and western Yunnan, SW China. Population decrease detected in all distribution areas except for Shuangbai and Xinping county where more than 60% of the total population is located. Only about 30% of the former bird population were recorded with the same interviewing method as 20 years ago.Three birds, 1 carcass, 6 calls and 12 footprints were detected along the 865 km line transects, indicating extremely low encounter rate of Green Peafowl in field. Sharp decreases in flock sizes were also detected, from 8-20 birds per flock in the 1990s to 3-5 birds at present. Poaching and habitat conversion are two widespread and long-lasting threats, while poison tion affect regional population＇s survival. Large flocks of 18 ng caused mortality in the past and hydropower construc -27 birds were discovered in the field, which increases our confidence of population recovery of this endangered pheasant in China.Conclusions： Only interviewed bird number and counts based on line transects were presented in this study, without further population estimation due to limitation of the data sets. Although the actual population of this cryptic bird must be underestimated, dramatic population declines and distribution concentrations of the endangered Green Peafowl occurred over the past 30 years in China undoubtedly.

The Breeding Ecology of a Critically Endangered Salamander,Hynobius amjiensis(Caudata：Hynobiidae),Endemic to Eastern China

Hynobius amjiensis is a critically endangered salamander species（IUCN Red List） endemic to eastern China. It currently has three known populations： one in Longwangshan, Zhejiang Province（type locality）, and two in Qingliangfeng between Anhui and Zhejiang Provinces. We examined the relatively unstudied breeding ecology of this species in the field and at laboratory from March 2007 to May 2014. Adult males and females were year-round terrestrial, except for the February–April breeding season. During this period, we captured only a total of 16 breeding adults（11 males and 5 females）. As few as 100 breeding females were estimated based on the number of egg sacs observed since 2007. This number was significantly reduced from the estimated number between 1992 and 1998. Males（mean total length = 16.21 cm, mean body mass = 18.8 g） were slightly smaller than females（16.51 cm, 19.2 g）. Size of breeding pools ranged from 0.2 m-2 to 1.2 m-2（0.1–1.2 m depths）. Each female deposits a pair of egg sacs by attaching the adhesive tips of the sacs to aquatic plants or dead twigs. Fifteen pairs of egg sacs had an average length of 28.6 cm and a diameter of 3.3 cm. On average, each egg sac contained 75 eggs with a diameter of 0.3 cm. Our field survey revealed that H. amjiensis used oviposition sites in small, cool, and weakly acidic pools at high elevations（1 300–1 600 m） where peat moss was abundant. Reduction in wetland size and disappearance of suitable breeding pools suggest that this salamander species is under threat of extinction, particularly at Longwangshan, where 5 of the 9 breeding pools have either dried up or disappeared. Combined size of the remaining 4 pools is less than 2 m-2. We urge immediate implementation of more effective conservation measures and suggest that preservation priority should be given to habitat that contains suitable breeding pools.

Recent changes in breeding abundance and distribution of the Common Pochard(Aythya ferina)in its eastern range

Background:The Common Pochard(Aythya ferina)(hereafter Pochard),a widespread and common freshwater diving duck in the Palearctic,was reclassified in 2015 from Least Concern to Vulnerable IUCN status based on rapid declines throughout its range.Analysis of its status,distribution and the potential causes for the decline in Europe has been undertaken,but there has never been a review of its status in the major part of its breeding range across Russia to the Pacific coast.Methods:We reviewed the scientific literature and unpublished reports,and canvassed expert opinion throughout Russia to assess available knowledge about changes in the species distribution and abundance since the 1980s.Results:While accepting available information may not be representative throughout the entire eastern range of the species,the review found marked declines in Pochard breeding abundance in the last two decades throughout European Russia.Pochard have also declined throughout Siberia.Declines throughout the steppe region seemed related to local drought severity in recent years,necessitating further research to confirm this climate link at larger spatial scales.Declines in the forest and forest-steppe regions appeared related to the major abandonment of fish farms in western Russia that had formerly provided habitat for breeding Pochard.However,hyper-eutrophication of shallow eutrophic lakes,cessation of grazing and haymaking in floodplain systems necessary to maintain suitable nesting habitat and disappearance of colonies of the Black-headed Gull(Chroicocephalus ridibundus)in a number of wetlands were also implicated.Increasing invasive alien predator species(e.g.American Mink Neovison vison and Raccoon Dog Nyctereutes procyonoides)and increasing spring hunting were also thought to contribute to declines.Reports of expansion in numbers and range only came from small numbers occurring in the Russian Far East,including on the border with China and the long-established isolated population on Kamchatka Peninsula.Conclusions:Widespread declines throughout the eastern breeding range of the Pochard give continued cause for concern.Although we could address all the potential causal factors identified above by management interventions,we urgently need better information relating to key factors affecting site-specific Pochard breeding success and abundance,to be able to implement effective actions to restore the species to more favourable conservation status throughout its breeding range.

The Impacts of Urbanization on the Distribution and Body Condition of the Rice-paddy Frog(Fejervarya multistriata) and Gold-striped Pond Frog(Pelophylax plancyi) in Shanghai,China

Previous studies have suggested that urbanization presents a major threat to anuran populations. However, very few studies have looked at the relationship between urbanization and anuran body condition. We investigated whether the distribution and body condition of the rice-paddy frog（Fejervarya multistriata） and gold-striped pond frog（Pelophylax plancyi） are influenced by increasing urbanization in Shanghai, China. Four study sites with six indicators of the major land-cover types were scored to indicate their position on an urbanization gradient. We found that both the density and body condition of F. multistriata declined significantly along this gradient. Although we observed a significant difference in body condition of P. plancyi among study sites with different degrees of urbanization, we did not find any corresponding significant differences in population density. Our results indicate that both the densities and body condition of these two anuran species show a negative relationship with increasing urbanization, but that the density of P. plancyi was only slightly affected in Shanghai.

Canine distemper virus as a threat to wild tigers in Russia and across their range

Canine distemper virus(CDV)has recently been identified in populations of wild tigers in Russia and India.Tiger populations are generally too small to maintain CDV for long periods,but are at risk of infections arising from more abundant susceptible hosts that constitute a reservoir of infection.Because CDV is an additive mortality factor,it could represent a significant threat to small,isolated tiger populations.In Russia,CDV was associated with the deaths of tigers in 2004 and 2010,and was coincident with a localized decline of tigers in Sikhote-Alin Biosphere Zapovednik(from 25 tigers in 2008 to 9 in 2012).Habitat continuity with surrounding areas likely played an important role in promoting an ongoing recovery.We recommend steps be taken to assess the presence and the impact of CDV in all tiger range states,but should not detract focus away from the primary threats to tigers,which include habitat loss and fragmentation,poaching and retaliatory killing.Research priorities include:(i)recognition and diagnosis of clinical cases of CDV in tigers when they occur;and(ii)collection of baseline data on the health of wild tigers.CDV infection of individual tigers need not imply a conservation threat,and modeling should complement disease surveillance and targeted research to assess the potential impact to tiger populations across the range of ecosystems,population densities and climate extremes occupied by tigers.Describing the role of domestic and wild carnivores as contributors to a local CDV reservoir is an important precursor to considering control measures.