Assessing the genetic integrity of captive and wild populations for reintroduction programs:the case of Cabot's Tragopan in China

Reintroduction of captive-bred animals into suitable habitats is an important technique for the long-term conservation and recovery of populations of endangered species in fragmented landscapes.Inbreeding depression is an inherent risk when using captive populations for reintroduction programs and needs to be carefully assessed prior to reintroduction.In this study,we evaluated inbreeding levels within a captive breeding program and one remnant wild population of Cabot's Tragopan (Tragopan caboti),an endangered pheasant species endemic to China,for which reintroduction is now an essential conservation strategy for long-term population persistence.Fifteen highly polymorphic microsatellite loci were developed to genotype individuals.Inbreeding coefficients (FIS) reveal that there is no evidence of inbreeding within the Tragopan Breeding Center of Beijing Normal University (TBCBNU) captive population and the remnant population from the Wuyi-Yandang Mountains.Diversity of origin,large founder population size and a rational breeding strategy are the most critical factors preventing inbreeding depression within the TBCBNU captive population.We suggest that the TBCBNU population is a suitable candidate stock for T.caboti reintroduction programs and that there is an urgent need to better coordinate and strengthen reproduction management of captive T.caboti populations to sustain the long-term ex situ conservation of the species.

Astragalus injection inhibits c-Jun N terminal kinase mRNA expression following oxygen-glucose deprivation and reintroduction in rat hippocampal neurons

BACKGROUND： In studies concerning cell injury induced by cerebral ischemia-reperfusion, current experiments have primarily focused on altered protein levels. In addition, the apoptotic proteins Bax and Bcl-2 have been thoroughly studied with regard to initiating neuronal apoptosis. OBJECTIVE： To establish an in vitro model of oxygen-glucose deprivation and reintroduction in the rat hippocampus to simulate cerebral ischemia-reperfusion injury; to observe c-Jun N-terminal kinase 3 （JNK3） mRNA expression in hippocampal neurons following Astragalus injection; and thus to determine changes in the signaling and downstream pathways of neuronal apoptosis at the cellular and molecular level. DESIGN, TIME AND SETTING： A randomized, controlled, cellular and molecular experiment was performed at the Department of Central Laboratory, Chengde Medical College from February to June 2008. MATERIALS： Astragalus injection, the main ingredient of astragaloside, was purchased from Chengdu Di＇ao Jiuhong Pharmaceutical Manufactory, China. JNK3 mRNA probe and in situ hybridization kit were purchased from Tianjin Haoyang Biological Technology, China, and JNK3 RT-PCR primers were designed by Shanghai Bio-engineering, China. METHODS： Primary cultures of hippocampal neurons derived from Sprague Dawley rats, aged 1 2 days, were established. After 8 days, the hippocampal neurons were assigned to the following interventions： model group, Astragalus group, and vehicle control group, cells were subjected to oxygen-glucose reintroduction after oxygen-glucose deprivation for 30 minutes in sugar-free Earle＇s solution and a hypoxia device, which contained high-purity nitrogen. The normal control group was subjected to primary culture techniques and was not treated using above-mentioned interventions. In addition, the Astragalus and vehicle control groups were treated with Astragalus injection （0.5 g/L raw drug） or sterile, deionized water at 2 hours prior to oxygen-glucose deprivation, respectively. MAIN OUTCOME MEASURES： JNK3 mRNA expression was measured by in situ hybridization and RT-PCR at 0, 0.5, 2, 6, 24, 72, and 120 hours after oxygen-glucose reintroduction. RESULTS： Hippocampal neuronal morphology was normal in the normal control group. Hippocampal neurons exhibited apparent apoptosis-like pathological changes in the model, as well as the vehicle control, groups. The apoptosis-like pathological changes in the hippocampal neurons were less in the Astragalus group. Results from in situ hybridization and RT-PCR showed that JNK3 mRNA expression significantly increased in hippocampal neurons from model group, as well as the vehicle control group, compared with the normal control group （P 〈 0.05）. In addition, JNK3 mRNA expression significantly decreased in hippocampal neurons of the Astragalus group, compared with the model group and vehicle control group （P 〈 0.05）. CONCLUSION： Astragalus injection inhibited apoptosis-related JNK3 mRNA expression following oxygen-glucose deprivation and reintroduction, and accordingly played a role in inhibiting hippocampal neuronal apoptosis.

Center for Plant Conservation's Best Practice Guidelines for the reintroduction of rare plants

Recent estimates indicate that one-fifth of botanical species worldwide are considered at risk of becoming extinct in the wild. One available strategy for conserving many rare plant species is reintroduction, which holds much promise especially when carefully planned by following guidelines and when monitored long-term. We review the Center for Plant Conservation Best Reintroduction Practice Guidelines and highlight important components for planning plant reintroductions. Before attempting reintroductions practitioners should justify them, should consider alternative conservation strategies, understand threats, and ensure that these threats are absent from any recipient site. Planning a reintroduction requires considering legal and logistic parameters as well as target species and recipient site attributes.Carefully selecting the genetic composition of founders, founder population size, and recipient site will influence establishment and population growth. Whenever possible practitioners should conduct reintroductions as experiments and publish results. To document whether populations are sustainable will require long-term monitoring for decades, therefore planning an appropriate monitoring technique for the taxon must consider current and future needs. Botanical gardens can play a leading role in developing the science and practice of plant reintroduction.

Comparing post-release survival and habitat use by captive-bred Cabot's Tragopan(Tragopan caboti) in an experimental test of soft-release reintroduction strategies

Background: Restoring a viable population by reintroduction is the ultimate goal of a large number of ex situ conservation projects for endangered animals. However, many reintroductions fail to establish a population in the wild, partly because released animals cannot acclimate to the native environment of the release site, resulting in very low survival rates. Acclimation training is a technique to resolve this problem, although it does not have positive results in all species. We tested whether acclimation training and soft-release could improve the reintroduction success for captive-bred Cabot's Tragopan(Tragopan caboti), an endangered pheasant in southern China.Methods: Reintroduction of captive-bred Cabot's Tragopan was carried out in the Taoyuandong National Nature Reserve, China from 2010 to 2011. We built a soft-release enclosure for acclimation training in the typical montane habitat of this pheasant. Nine birds were acclimated to the environment of this release site in this cage for more than 50 days before release("trained birds"), while 11 birds remained only in the cage for 3 days prior to release("untrained birds"). Released birds were tagged with a collar radio-transmitter.Results: Post-release monitoring revealed that the survival rate of trained birds was higher than that of untrained birds after 50 days(trained: 85.7%; untrained: 20.0%). Cox regression analysis showed that there was a significant difference in the mortality rates between the trained and untrained birds. In addition, a survey of the habitat of the experimental and the control groups showed significant differences in habitat selection between the groups.Conclusion: Our study suggests that pre-release acclimatization training is an important factor that can lead to improved survival and habitat selection of captive-bred reintroduced tragopans.

Correlation between aquaporin-4 and brain edema in an animal model of astrocytic oxygen-glucose deprivation and reintroduction

BACKGROUND：Previous studies have demonstrated that aquaporin-4 （AQP4） plays a key role in the formation and resolution of brain edema.However,the molecular mechanisms and role of AQP4 in hypoxia-ischemia-induced brain edema remain poorly understood.OBJECTIVE：To establish a newborn animal model of astrocytic oxygen-glucose deprivation and reintroduction,to observe the correlation between AQP4 and cellular volume,and to investigate the role of AQP4 in the development of brain edema following oxygen deprivation and reintroduction.DESIGN,TIME AND SETTING：A comparative experiment was performed at the Experimental Center of West China Second University Hospital between October 2007 and April 2009.MATERIALS：Astrocytes were derived from the neocortex of Sprague Dawley rats aged 3 days.METHODS：Astrocytes were incubated in glucose/serum-free Dulbecco＇s modified Eagle＇s medium,followed by 1% oxygen for 6 hours.Finally,oxygen-glucose deprivation and reintroduction models were successfully established.MAIN OUTCOME MEASURES：Real-time polymerase chain reaction and Western blot analysis were used to measure expression of AQP4 mRNA and protein in cultured rat astrocytes following oxygen-glucose deprivation and reintroduction.Astrocytic cellular volume,as determined by [3H]-3-O-methyl-D-glucose,was used to represent the extent of astrocytic swelling.RESULTS：During oxygen-glucose deprivation,AQP4 mRNA and protein expression gradually decreased in astrocytes,whereas cellular volume increased in a time-dependent manner （P〈 0.01）.Following oxygen-glucose reintroduction,AQP4 mRNAand protein expression was upregulated,peaked at day 7,and then gradually decreased,but still higher than normal levels （P 〈 0.05）.However,cellular volume gradually decreased （P 〈 0.01）,and then reached normal levels at day 7.CONCLUSION：AQP4 expression highly correlated with cellular volume changes,suggesting that AQP4 played an important role in modulating brain water transport in an astrocytic oxygen-glucose deprivation and reintroduction model.

Morphological differences of hindlimb levers between wild and farmed American mink(Neovison vison)and implications for reintroduction of mustelids

Reintroduction is an important strategy to restore or re-establish wild populations of endangered species.Pre-release training is a necessary step to ensure postreintroduction survival.However,studies reported contradicting outcomes after pre-release training of juveniles and adults.This study used farmed and feral American mink(Neovison vison)to analyze the influence of captive breeding on the morphology,structure and efficiency of the two major hindlimb levers,the femur and tibia pivoted by hip and knee joints that are essential for locomotion.Results showed that captive breeding did not alter the sexual dimorphism of the two levers that are related to survival in the wild.Captive-bred mink showed slightly altered morphology of the femur and fundamental structure of the hindlimb levers that improved efficiency,but this resulted in reduction of performance related to foraging in both terrestrial and aquatic environments,especially for females.These findings suggest that reintroduction of mustelid as exampled by the mink here should focus on juveniles because the skeletal alterations associated with captive rearing were recorded only among adults and are irreversible in adulthood.In contrast,captive-reared juveniles showed no skeletal alterations and would be expected to recovery from any atrophy of the muscular system caused by captive rearing for shorter durations.Our results support the application of pre-release training of juveniles in enriched environments as a method for alleviating structural alteration of appendages and enhancing locomotion to increase survival probability in complex habitats.

The Successful Reintroduction of the White Stork(Ciconia ciconia)into the Alpine Rhine Valley between 1984 and 2018

This study demonstrates that a regionally extinct bird species belonging to the long-distance migrants can be reintroduced under the right circumstances.The article first describes the historic distribution of the white stork(Ciconia ciconia)prior to its disappearance from the Alpine Rhine Valley.Furthermore,the study examines the increase in actual population size between 1984 and 2018,mean reproductive success per breeding pair in the Rhine Valley between 2011 and 2018 and compares different types of breeding sites.Finally,the factors facilitating the successful reintroduction of the species are discussed.

Suitability of the South Caribbean Coast of Costa Rica for Reintroduction of the Great Green Macaw <i>Ara ambiguus</i>

The Great Green Macaw Ara ambiguus is an endangered species whose most important food resource and nesting site in Costa Rica is the mountain almond tree Dipteryx panamensis, threatened mainly by deforestation. In this study, we analyse the suitability of reintroducing A. ambiguus in the South Caribbean Coast of Costa Rica by examining whether the ecological and socio-cultural conditions required for the reintroduction are met in the area. The methods developed in this work include biological sampling, cartographical analysis and semi-structured interviews, among others. We set La Ceiba Nature Reserve as study unit and starting point of the analysis due both to its conservation status, favouring the potential release of individuals, and its ecosystem representativeness. Our results suggest that the habitat is suitable for reintroduction, with frequent presence of D. panamensis in the region, as well as other feeding options and potential nesting sites in the study area. The cartographic study reveals that the species could rely on a forested surface of up to 7000 hectares, which would be sufficient for sustaining a viable population. As for the socio-cultural analysis, illegal logging and low protective frameworks were identified as the main potential threats for the species. Nevertheless, we perceived positive conservation attitudes among local people and a pro-active commitment of political stakeholders. We conclude that a viable South Caribbean reintroduction of A. ambiguus is possible in conjunction with a threat mitigation programme.

Advances in the reintroduction of rare and endangered wild plant species

Human disturbance and climate change have increased the risk of extinction for rare and endangered wild plant species.One effective way to conserve these rare and endangered species is through reintroduction.In this review,we summarize the advances in wild plant reintroduction from five perspectives:the establishment of reintroduction biology as an important tool for biodiversity conservation;the importance of genetic diversity in reintroduction;reintroduction under global climate change;recruitment limitation in reintroduction;and reintroduction and ecological restoration.In addition,we consider the future of plant reintroduction strategies.

Using the movement patterns of reintroduced animals to improve reintroduction success

Despite their importance to conservation, reintroductions are still a risky endeavor and tend to fail, highlighting the need for more efficient post-release monitoring techniques. Reintroduced animals are released into unfamiliar novel environ ments and must explore their surroundings to gain knowledge in order to survive. According to theory, knowledge gain should be followed by subsequent changes to the animal＇s movement behavior, making movement behavior an excellent indicator of reintroduction progress. We aim to conceptually describe a logical process that will enable the inclusion of behavior （in particular, movement behavior） in management decision-making post-reintroductions, and to do so, we provide four basic components that a manager should look for in the behaviors of released animals. The suggested components are release-site fidelity, recurring locations, proximity to other individuals, and individual variation in movement behavior. These components are by no means the only possible ones available to a manager, but they provide an efficient tool to understanding animals＇ decision-making based on ecological theory; namely, the exploration-exploitation trade-off that released animals go through, and which underlies their behavior. We demonstrate our conceptual approach using data from two ungulate species reintroduced in Israel： the Persian fallow deer Dama mesopotamica and the Arabian oryx Oryx leucoryx [Current Zoology 60 （4）： 515-526, 2014] .

An assessment of African lion Panthera leo sociality via social network analysis： prerelease monitoring for an ex situ reintroduction program

The wild population of the African lion Panthera leo continues to decline, requiring alternate conservation programs to be considered. One such program is ex situ reintroduction. Prior to release, longterm monitoring and assessment of behavior is required to determine whether prides and coalitions behave naturally and are sufficiently adapted to a wild environment. Social network analysis （SNA） can be used to provide insight into how the pride as a whole and individuals within it, function. Our study was conducted upon 2 captive-origin prides who are part of an ex situ reintroduction program, and 1 wild pride of African lion. Social interactions were collected at all occurrence for each pride and categorized into greet, social grooming, play, and aggression. Betweenness centrality showed that offspring in each pride were central to the play network, whereas degree indicated that adults received （indegree） the greatest number of overall social interactions, and the adult males of each pride were least likely to initiate （outdegree） any interactions. Through the assessment of individual centrality and degree values, a social keystone adult female was identified for each pride. Social network results indicated that the 2 captive-origin prides had formed cohesive social units and possessed relationships and behaviors comparable with the wild pride for the studied behaviors. This study provided the first SNA comparison between captive-bred origin and a wild pride of lions, providing valuable information on individual and pride sociality, critical for determining the success of prides within an ex situ reintroduction program.

Conservation and reintroduction of the rare and endangered orchid Paphiopedilum armeniacum

Paphiopedilum armeniacum is a rare and endangered lady’s slipper orchid in China.It is distributed around the mid-elevations of the Nu Mountains in southwest China.Due to over-harvest,habitat loss,and degradation,wild populations of P.armeniacum has declined drastically.A combination of approaches involving biotechnology,habitat restoration,and interspecific relationship reconstruction was used to carry out the reintroduction of the species.Integrated conservation program for this species included in-situ protection,ex-situ conservation,and reintroduction,which helped to rebuild a harmonious relationship between local farmers and P.armeniacum.The sustainable utilization of native plant resources in poor areas can promote regional sustainable development which is compatible with species protection.

Can we reestablish a self-sustaining population?A case study on reintroduced Crested Ibis with population viability analysis

Background:One of the most challenging tasks in wildlife conservation and management is clarifying which and how external and intrinsic factors influence wildlife demography and long-term viability.The wild population of the Crested Ibis(Nipponia nippon)has recovered to approximately 4400,and several reintroduction programs have been carried out in China,Japan and Korea.Population viability analysis on this endangered species has been limited to the wild population,showing that the long-term population growth is restricted by the carrying capacity and inbreeding.However,gaps in knowledge of the viability of the reintroduced population and its drivers in the release environment impede the identification of the most effective population-level priorities for aiding in species recovery.Methods:The field monitoring data were collected from a reintroduced Crested Ibis population in Ningshan,China from 2007 to 2018.An individual-based VORTEX model(Version 10.3.5.0)was used to predict the future viability of the reintroduced population by incorporating adaptive patterns of ibis movement in relation to catastrophe frequency,mortality and sex ratio.Results:The reintroduced population in Ningshan County is unlikely to go extinct in the next 50 years.The popula-tion size was estimated to be 367,and the population genetic diversity was estimated to be 0.97.Sensitivity analysis showed that population size and extinction probability were dependent on the carrying capacity and sex ratio.The carrying capacity is the main factor accounting for the population size and genetic diversity,while the sex ratio is the primary factor responsible for the population growth trend.Conclusions:A viable population of the Crested Ibis can be established according to population viability analysis.Based on our results,conservation management should prioritize a balanced sex ratio,high-quality habitat and low mortality.

An approach on the survivorship of giant panda in wild

The endangered giant panda (Ailuropoda melanoleuca) is endemic to th e mountains of Sichuan, Gansu and Shaanxi Provinces in China. The species had nu mbered over 2000 animals in early 1970s, but declined to no more than 1,000 anim als fragmented into perhaps 32 subpopulations in late 1990s as the result of num erous detrimental forces such as habitat shrinking, poaching and bamboo flowerin g. The mass flowering and followed die-off of bamboo played key roles in the dec lination of panda population in the past three decades. It trigged the starvatio n and following high mortality of giant pandas in 1970s over Min Mountains and i n 1980s across Qionglai Mountains in Sichuan Province. The situation of survivor ship is made worse by the fact that the panda habitat is fragmented into many sm all 'islands', each containing only a few pandas. Such small, isolated panda pop ulations are rendered even more vulnerable to extinction form threats such as ha bitat degradation, natural disaster, disease, and the deleterious effects of inb reeding. So restoring the panda habitat and reintroduction pandas to their histo rical habitat might be an important issue for protecting the giant panda in wild .

Nest-site Use by the Chinese Alligator (Alligator sinensis) in the Gaojingmiao Breeding Farm,Anhui,China

Nest-site and nesting material used by the Chinese alligator （Alligator sinensis） was studied at the Gaojingmiao Breeding Farm, Langxi County, Anhui, China from May to September 2009. In this study, artificial nesting materials were placed in 43 potential nesting sites before the nesting season, 11 of which were used. Additionally, eight nests were built at natural sites without artificial nesting materials provided. Seven environmental variables were measured at each nest site： distance from water, height from water surface, sunlight duration, nearest bank slope, nest site slope, vegetation coverage and concealment. Statistical analyses indicated that concealment was significantly different between used and unused nest sites, with concealment being significantly correlated to the use of materials- placed sites. In comparing the nests at artificial vs. natural sites, only the nearest bank slope differed significantly. Further, principal component analysis of natural nests indicated that the duration of nest exposure to sunlight and vegetation coverage were more influential than the other factors studied.

Factors affecting post-release survival and dispersal of reintroduced Crested Ibis(Nipponia nippon)in Tongchuan City,China

Reintroduction has become a common conservation management tool to restore endangered species in their historical range.However,many attempts have failed to establish self-sustaining populations in the wild.The success of reintroductions could be improved by varying release strategies.Therefore,it is vital to determine the factors influencing reintroduction outcomes.To better understand the post-release settlement and to optimize the release strategy of the Crested Ibis(Nipponia nippon),we quantified the effects of age,sex,acclimation duration,and the timing of release events on post-release survival and dispersal distance for the released Crested Ibis in Tongchuan City,Shaanxi Province,using a generalized linear mixed effect modeling approach.Our results indicate that 40–56.3%of the released individuals survived the first year following release.Mortality was attributable to flight collisions,starvation,disease,and unknown reasons.The post-release survival probability of ibises showed a negative association with age(estimate=-0.186;95%CI:-0.350 to-0.022;P=0.026),and post-release dispersal distance was affected by the timing of release event(estimate=0.718;95%CI:0.025 to1.253;P=0.042).However,sex and acclimation period duration did not cause detectable differences in postrelease survival probability and dispersal distance.Based on our results,optimal release strategies for establishing a reintroduced population of the Crested Ibis include:(1)release of sub-adults biased and sex ratio balanced initial groups;(2)release during the non-breeding season;and(3)food supplementation immediately after release.

Recovery and Development of Siberian Tiger Populations in China

Siberian tiger (Panthera tigris aitaica Temminck) is the largest cat in the world. The wild population isabout 250. The population in China decreased from 120 in mid 1970's to less than 20 now. Hengdaohezi Felidae BreedingCenter was established in Heilongjiang province in 1986. The Sibcrian tigers were fed artiticially and were trained to reintroduce primarily. The population increased from eight to scventy by hard work for about ten years. In the meantime, the researchers have done much research work on physiology, biochcmistry, brecding, behavior, disease prevention and so on,they have got much valuable infonnation of tigcr population. In January, 1996, 'Siberian Tiger Park' was built on the eastside of The Sun Island in Harbin. The China's unique and the world's largest Siberian Tiger groups are being domesticatedhere. Because of the change of the living condition, the focal point of th1c tiger pop[llatiol1 l11al1ageme1lt is now to reintroducethe tigers. So, the tigers are being trained to lcarn how to prey in the wild, how to adapt the bad nature environment and increase the ability of disease prevention. Tourists can cnter the purk by tour bus or by their own car. The income of the parktickets can be used to build the park and dcvclop the tiger population. It is a good opportunity to increase the consciousnessof Man's protecting wildlife The largc camivorcs can coexist in the world with Man.

Biologging is suspect to cause corneal opacity in two populations of wild living Northern Bald Ibises (Geronticus eremita)

Background:In this paper,we present evidence that biologging is strongly correlated with eye irritation,with sometimes severely impairing effects.A migratory population of the Northern Bald Ibis(Geronticus eremita,NBI)is reintroduced in Europe,in course of a LIFE+project.Since 2014,all individuals have been equipped with GPS-devices.Remote monitoring allows the implementation of focussed measures against major mortality causes.Methods:Initially all birds carried battery-powered devices,fixed on the lower back of the birds.Since 2016 an increasing amount of birds has been equipped with solar-powered devices,fixed on the upper back,the more sunexposed position.In 2016,we observed opacity in the cornea of one eye(unilateral corneal opacity;UCO)during a regular health monitoring for the first time.Results:By 2018,a total of 25 birds were affected by UCO,with varying intensity up to blindness.Clinical examination of the birds revealed no clear cause for the symptoms.However,only birds carrying a device on the upper back were affected(2017 up to 70%of this group).In contrast,none of the birds carrying devices on the lower back ever showed UCO symptoms.This unexpected relationship between tagging and UCO was discovered in 2017.After we took countermeasures by removing the device or repositioning it on the lower back,we observed an immediate reduction of the incidence rate without any new cases reported since January 2019.NBI roost with their head on the back,one eye closely placed to the device if it was positioned on the upper back.Thus,we conclude that the most parsimonious explanation for the symptomatology is either a repetitive slight temperature rise in the corneal tissue due to electromagnetic radiation by the GSM module of the device or a repetitive slight mechanical irritation of the corneal surface.Concrete evidence is missing so far.Meanwhile,cases of UCO were found in another NBI population.Conclusion:Our observations indicate that further research in the fast-growing field of biologging is urgently needed.The findings question the positioning of devices on the upper back in birds roosting with the head on the back.

Trastuzumab Re-Introduction with FOLFIRI for Treatment of HER2 Overexpression-Advanced Gastric Adenocarcinoma Following Failure of Other Trastuzumab-Based Chemotherapy Regimens

A 67-year-old man diagnosed with HER2 overexpression advanced gastric adenocarcinoma and metastasis to liver and lungs was admitted for tertiary care. He received a third line chemotherapy that consists of trastuzumab combined with FOLFIRI regimen (irinotecan plus 5-FU/LV) following a disease relapse after an initial successful response to a combination of 5FU + oxaliplatin and trastuzumab. The patient showed a favorable and prolonged response to it. In addition the chemotherapy was well tolerated and devoid of remarkable side effects. The response to trastuzumab + FOLFIRI was assessed clinically and through CT scan imaging and upper gastrointestinal endoscopy. This case report shows that firstly the combination of FOLFIRI and trastuzumab could be tested as another regimen in metastatic gastric cancer, and, secondly, that in this disease, like in metastatic breast cancer, the continuation of trastuzumab after an initial progression under this antibody could be tested in order to improve the efficacy of the treatment Trastuzumab re-introduction with FOLFIRI for treatment of HER2 overexpression-advanced gastric adenocarcinoma following failure of other trastuzumab-based chemotherapy regimens.

Social networks of reintroduced Przewalski's horses in the Great Gobi B Strictly Protected Area (Mongolia)

Analyzing social networks is a powerful tool for understanding the ecology of social species.While most studies focus on the role of each group member,few compare groups with different characteristics.The current population of Przewalski's horses Equus ferus przewalskii at the Great Gobi B Strictly Protected Area(Mongolia)includes groups of wild-born and captive-bred individuals with different experiences with the area(acclimatizing,long-term reintroduced,and wild-born),therefore serving as an ideal natural behavioral lab.We filmed 11 groups for 141.5 hours in summer 2018(July),late spring 2019(May,June),and autumn 2019(September,October).Affiliative and agonistic interactions were recorded,and social networks were created.We tested the influence of origin,experience,season,sex,age,relative time belonging to the group,relat-edness,and dominance rank on different network indices at the individual and group levels.We found that groups with greater experience in the area are generally better connected than members of the newly formed groups.However,these strong networks were created by wild-born individuals with very low interaction rates.On the contrary,inexperienced groups composed of captive-bred individuals displayed many inter actions but created weak social networks.The results show a trend of behavioral transition from acclimatizing through long-term reintroduced to wild-born groups,supporting that the newly formed groups of released Przewalski's horses need time to display the typical social behavior patterns of wild-born individuals.Long-term monitoring of released Przewalski's horses is recommended to promote the success of this reintroduction program.