The population dynamics and breeding behaviors of Black-crowned Night Herons ( Nycticorax nycticorax ), Egrets (Egtetta garzetta), Chinese Pond Herons (Ardeola bacchus) and Great Egrets (Casmerodius albus) wer...The population dynamics and breeding behaviors of Black-crowned Night Herons ( Nycticorax nycticorax ), Egrets (Egtetta garzetta), Chinese Pond Herons (Ardeola bacchus) and Great Egrets (Casmerodius albus) were observed in Tanghai Wetlands, Hebei Province from August 2004 to July 2005. Further, we studied the relationship of nest space distribution and directly calculated the nest density of vertical and horizontal levels, the niche overlapping index and the niche breadth. The results showed that there were two breeding areas, named Area Ⅰ and Area Ⅱ . The maximum population occurred in the period from April to September and was approximately 5800 individuals. Area Ⅰ was occupied earlier than Area Ⅱ by approximately half a month. In the breeding period, Black-crowned Night Herons were dominant in numbers and most occupied the upper nests of the core areas. Great Egrets also took the upper nests but they have the smallest population. Most Egrets took the middle nests of the edges of the area. Chinese Pond Herons, with a smaller population than the Egret, mostly nested in the edges, but some of them also took the lower nests of the core area. On the whole, the vertical niche of Egrets is the widest, the horizontal niche of Black-crowned Night Herons is the widest and the niche breadth of Chinese Pond Herons is the largest. The nest distribution pattern is the most similar between Chinese Pond Herons and Black-crowned Night Herons, and the niche overlapping index of Chinese Pond Herons and Egrets is the largest. Black-crowned Night Herons and Great Egrets control Egrets and Chinese Pond Herons in competition. Rich food and the optimal ecological environments lead to plenty of herons in the wetlands. In addition, it is a distinguishing feature of the four species that nests are built in poplar trees over 22 m tall.展开更多
Background: Breeding dispersal is an important ecological process that affects species' population dynamics and colonization of new suitable areas. Knowledge of the causes and consequences of breeding dispersal is...Background: Breeding dispersal is an important ecological process that affects species' population dynamics and colonization of new suitable areas. Knowledge of the causes and consequences of breeding dispersal is fundamental to our understanding of avian ecology and evolution. Although breeding success for a wild and reintroduced population of the Crested Ibis(Nipponia nippon) has been reported, the relationships between individuals' breeding dispersal and their breeding success, age and sex remain unclear.Methods: Ibises' breeding dispersal distance, which is the distance moved by adults between sites of reproduction, was estimated based on the observations of consecutive breeding sites of marked ibis individuals. From observational and capture-recapture data(n as = 102) over 9 years, individuals' breeding dispersal probability in relation to age, sex, and reproductive success wanalyzed via a generalized linear mixed effect modeling approach.Results: Our results show that 55% males and 51% females keep their previous territories following nesting success. Failed breeding attempts increased dispersal probabilities. Both females and males failed in breeding were more likely to disperse with greater distances than successful birds(females: 825 ± 216 m vs 196 ± 101 m, males: 372 Crested Ibis exhibited a female-biased dispersal pattern that the mean dispersal distance± 164 m vs 210 ± 127 m). of females(435 ± 234 m) was much larger than that of males(294 ± 172 m).Conclusion: Our results are fundamental to predict the patterns of breeding dispersal related to reproductive success under different release sites. From the conservation point of view, landscape connectivity between the reintroduced populations should be taken into account in accordance with the distance of breeding dispersal.展开更多
In the face of worldwide amphibian declines,integrative studies combining individual-based information and genetic data represent a powerful approach to produce robust,reliable,and comparable assessments of demographi...In the face of worldwide amphibian declines,integrative studies combining individual-based information and genetic data represent a powerful approach to produce robust,reliable,and comparable assessments of demographic dynamics.The Iberian painted frog(Discoglossus galganoi)is endemic to Spain and Portugal and shows decreasing population trends across its range,but few studies have attempted to estimate census sizes or assess genetic diversity in wild populations,and little is known about their reproductive biology.We applied an integrative approach based on the combination of capture-mark-recapture data and multilocus genotypes to monitor a breeding population of D.galganoi in central Spain during two consecutive breeding seasons,focusing on the estimation of demographic parameters and their temporal variation.Specifically,we estimated the number of adults(Na),the effective population size(Ne),and the effective number of breeders(Nb),as well as survival and migration rates.We documented a>50%decrease in the estimated number of adults of both sexes between the breeding seasons of 2018 and 2019,probably associated with reduced rainfall in the latter.Estimates of Nb and the Nb/Na ratio were low in both seasons,with a 20–30%decrease in Nb and a 47%increase in the Nb/Na ratio in 2019.Based on the reconstruction of pedigrees from larval and adult genotypes,we provide the first genetic evidence of polygamy in males and females of D.galganoi and the first estimates of breeding success in the species.展开更多
In this work,we report long-term trends in the abundance and breeding performance of Adélie penguins(Pygoscelis adeliae)nesting in three Antarctic colonies(i.e.,at Martin Point,South Orkneys Islands;Stranger Poin...In this work,we report long-term trends in the abundance and breeding performance of Adélie penguins(Pygoscelis adeliae)nesting in three Antarctic colonies(i.e.,at Martin Point,South Orkneys Islands;Stranger Point/Cabo Funes,South Shetland Islands;and Esperanza/Hope Bay in the Antarctic Peninsula)from 1995/96 to 2022/23.Using yearly count data of breeding groups selected,we observed a decline in the number of breeding pairs and chicks in crèche at all colonies studied.However,the magnitude of change was higher at Stranger Point than that in the remaining colonies.Moreover,the index of breeding success,which was calculated as the ratio of chicks in crèche to breeding pairs,exhibited no apparent trend throughout the study period.However,it displayed greater variability at Martin Point compared to the other two colonies under investigation.Although the number of chicks in crèche of Adélie penguins showed a declining pattern,the average breeding performance was similar to that reported in gentoo penguin colonies,specifically,those undergoing a population increase(even in sympatric colonies facing similar local conditions).Consequently,it is plausible to assume a reduction of the over-winter survival as a likely cause of the declining trend observed,at least in the Stranger Point and Esperanza colonies.However,we cannot rule out local effects during the breeding season affecting the Adélie population of Martin Point.展开更多
Understanding the reproductive strategy of an organism is important in conservation ecology as it directly affects the population performance under changing environmental conditions.Chinese sturgeon(Acipenser sinensis...Understanding the reproductive strategy of an organism is important in conservation ecology as it directly affects the population performance under changing environmental conditions.Chinese sturgeon(Acipenser sinensis)are the largest anadromous fish in the Yangtze River,China.Currently,the species has only one spawning ground and has failed to spawn in recent years,leading it to the brink of extinction.To develop effective conservation measures,a further understanding of its reproductive strategy is needed.In our study,we conducted kinship analyses by using mitochondrial and microsatellite DNA data from 216 wild juveniles collected over nine years(20062013,2015)to understand the mating system,breeding interval,effective number of breeding adults,and reproductive success.The results from these analyses suggested polygynandry,with some parents contributing up to eight half-sibling juvenile genotypes.Although the spawning ground was restricted to a limited area,genetic diversity was maintained at a relatively high level(observed heterozygosity from 0.698 to 0.787 and expected heterozygosity from 0.763 to 0.787)and inbreeding coefficients in each year-class ranged from1% to 9%(low to modest detrimental effects on offspring).A parental inference analysis revealed that Chinese sturgeon have a breeding interval of 2-6 years,indicating that it has the potential to feed,accumulate nutrition in the ocean,and then migrate back to the Yangtze River for iteroparous reproduction.The annual effective number of breeders in the Yangtze River ranged from 14 to 161 during the study period,and it decreased by 62.1%from the 20112014 year-classes.This sharp population decline likely contributes to the reproduction failure.However,the ratios of effective to census population size(Ne/Nc)were all larger than 0.20 after the 2010 year-class,indicating relatively even reproductive success.Based on these results,a suggested approach to protect this species is to restock parent fish to increase the reproductive stock size and optimize the discharge of the Three Gorges Dam to reduce the unsuitable hydrological conditions and rehabilitate spawning ground habitats.展开更多
文摘The population dynamics and breeding behaviors of Black-crowned Night Herons ( Nycticorax nycticorax ), Egrets (Egtetta garzetta), Chinese Pond Herons (Ardeola bacchus) and Great Egrets (Casmerodius albus) were observed in Tanghai Wetlands, Hebei Province from August 2004 to July 2005. Further, we studied the relationship of nest space distribution and directly calculated the nest density of vertical and horizontal levels, the niche overlapping index and the niche breadth. The results showed that there were two breeding areas, named Area Ⅰ and Area Ⅱ . The maximum population occurred in the period from April to September and was approximately 5800 individuals. Area Ⅰ was occupied earlier than Area Ⅱ by approximately half a month. In the breeding period, Black-crowned Night Herons were dominant in numbers and most occupied the upper nests of the core areas. Great Egrets also took the upper nests but they have the smallest population. Most Egrets took the middle nests of the edges of the area. Chinese Pond Herons, with a smaller population than the Egret, mostly nested in the edges, but some of them also took the lower nests of the core area. On the whole, the vertical niche of Egrets is the widest, the horizontal niche of Black-crowned Night Herons is the widest and the niche breadth of Chinese Pond Herons is the largest. The nest distribution pattern is the most similar between Chinese Pond Herons and Black-crowned Night Herons, and the niche overlapping index of Chinese Pond Herons and Egrets is the largest. Black-crowned Night Herons and Great Egrets control Egrets and Chinese Pond Herons in competition. Rich food and the optimal ecological environments lead to plenty of herons in the wetlands. In addition, it is a distinguishing feature of the four species that nests are built in poplar trees over 22 m tall.
基金completely supported by the National Nature Science Foundation of China(Nos.31572282 and 31172103)
文摘Background: Breeding dispersal is an important ecological process that affects species' population dynamics and colonization of new suitable areas. Knowledge of the causes and consequences of breeding dispersal is fundamental to our understanding of avian ecology and evolution. Although breeding success for a wild and reintroduced population of the Crested Ibis(Nipponia nippon) has been reported, the relationships between individuals' breeding dispersal and their breeding success, age and sex remain unclear.Methods: Ibises' breeding dispersal distance, which is the distance moved by adults between sites of reproduction, was estimated based on the observations of consecutive breeding sites of marked ibis individuals. From observational and capture-recapture data(n as = 102) over 9 years, individuals' breeding dispersal probability in relation to age, sex, and reproductive success wanalyzed via a generalized linear mixed effect modeling approach.Results: Our results show that 55% males and 51% females keep their previous territories following nesting success. Failed breeding attempts increased dispersal probabilities. Both females and males failed in breeding were more likely to disperse with greater distances than successful birds(females: 825 ± 216 m vs 196 ± 101 m, males: 372 Crested Ibis exhibited a female-biased dispersal pattern that the mean dispersal distance± 164 m vs 210 ± 127 m). of females(435 ± 234 m) was much larger than that of males(294 ± 172 m).Conclusion: Our results are fundamental to predict the patterns of breeding dispersal related to reproductive success under different release sites. From the conservation point of view, landscape connectivity between the reintroduced populations should be taken into account in accordance with the distance of breeding dispersal.
基金the Ethics Committee of Consejo Superior de Investigaciones Científicas,Spain(ref.:710/2018)and Comunidad de Madrid(ref.:PROEX 040/19)which also extended legal permits for tissue collection for scientific purposes(ref.:10/069513.9/18).
文摘In the face of worldwide amphibian declines,integrative studies combining individual-based information and genetic data represent a powerful approach to produce robust,reliable,and comparable assessments of demographic dynamics.The Iberian painted frog(Discoglossus galganoi)is endemic to Spain and Portugal and shows decreasing population trends across its range,but few studies have attempted to estimate census sizes or assess genetic diversity in wild populations,and little is known about their reproductive biology.We applied an integrative approach based on the combination of capture-mark-recapture data and multilocus genotypes to monitor a breeding population of D.galganoi in central Spain during two consecutive breeding seasons,focusing on the estimation of demographic parameters and their temporal variation.Specifically,we estimated the number of adults(Na),the effective population size(Ne),and the effective number of breeders(Nb),as well as survival and migration rates.We documented a>50%decrease in the estimated number of adults of both sexes between the breeding seasons of 2018 and 2019,probably associated with reduced rainfall in the latter.Estimates of Nb and the Nb/Na ratio were low in both seasons,with a 20–30%decrease in Nb and a 47%increase in the Nb/Na ratio in 2019.Based on the reconstruction of pedigrees from larval and adult genotypes,we provide the first genetic evidence of polygamy in males and females of D.galganoi and the first estimates of breeding success in the species.
基金Nacional de Promoción Científica y Tecnológica(Grant:PICTO 2010-0111)the Instituto Antártico Argentino-Dirección Nacional del Antártico(PINST-05)provided financial and logistical support.
文摘In this work,we report long-term trends in the abundance and breeding performance of Adélie penguins(Pygoscelis adeliae)nesting in three Antarctic colonies(i.e.,at Martin Point,South Orkneys Islands;Stranger Point/Cabo Funes,South Shetland Islands;and Esperanza/Hope Bay in the Antarctic Peninsula)from 1995/96 to 2022/23.Using yearly count data of breeding groups selected,we observed a decline in the number of breeding pairs and chicks in crèche at all colonies studied.However,the magnitude of change was higher at Stranger Point than that in the remaining colonies.Moreover,the index of breeding success,which was calculated as the ratio of chicks in crèche to breeding pairs,exhibited no apparent trend throughout the study period.However,it displayed greater variability at Martin Point compared to the other two colonies under investigation.Although the number of chicks in crèche of Adélie penguins showed a declining pattern,the average breeding performance was similar to that reported in gentoo penguin colonies,specifically,those undergoing a population increase(even in sympatric colonies facing similar local conditions).Consequently,it is plausible to assume a reduction of the over-winter survival as a likely cause of the declining trend observed,at least in the Stranger Point and Esperanza colonies.However,we cannot rule out local effects during the breeding season affecting the Adélie population of Martin Point.
基金funded by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB31000000)the National Key R&D Program of China(2018YFD0900806)+1 种基金National Natural Science Foundation of China(31872234)the research program of China Three Gorges Corporation(201903144).
文摘Understanding the reproductive strategy of an organism is important in conservation ecology as it directly affects the population performance under changing environmental conditions.Chinese sturgeon(Acipenser sinensis)are the largest anadromous fish in the Yangtze River,China.Currently,the species has only one spawning ground and has failed to spawn in recent years,leading it to the brink of extinction.To develop effective conservation measures,a further understanding of its reproductive strategy is needed.In our study,we conducted kinship analyses by using mitochondrial and microsatellite DNA data from 216 wild juveniles collected over nine years(20062013,2015)to understand the mating system,breeding interval,effective number of breeding adults,and reproductive success.The results from these analyses suggested polygynandry,with some parents contributing up to eight half-sibling juvenile genotypes.Although the spawning ground was restricted to a limited area,genetic diversity was maintained at a relatively high level(observed heterozygosity from 0.698 to 0.787 and expected heterozygosity from 0.763 to 0.787)and inbreeding coefficients in each year-class ranged from1% to 9%(low to modest detrimental effects on offspring).A parental inference analysis revealed that Chinese sturgeon have a breeding interval of 2-6 years,indicating that it has the potential to feed,accumulate nutrition in the ocean,and then migrate back to the Yangtze River for iteroparous reproduction.The annual effective number of breeders in the Yangtze River ranged from 14 to 161 during the study period,and it decreased by 62.1%from the 20112014 year-classes.This sharp population decline likely contributes to the reproduction failure.However,the ratios of effective to census population size(Ne/Nc)were all larger than 0.20 after the 2010 year-class,indicating relatively even reproductive success.Based on these results,a suggested approach to protect this species is to restock parent fish to increase the reproductive stock size and optimize the discharge of the Three Gorges Dam to reduce the unsuitable hydrological conditions and rehabilitate spawning ground habitats.