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The reintroduced Eastern Migratory Population (EMP) of Whooping Cranes (Grus americana) has exhibited appropriate breeding behavior, including pair formation, territory defense, nest building, and fertile egg production. However, recruitment has been lower than what is needed for a self‐sustaining population due to high chick mortality. During 2006–2023, 194 chicks hatched in the EMP, with only 36 surviving to fledging. For the population to succeed without continued releases of captive‐reared individuals, we must develop management strategies that increase recruitment to a level above mortality rates. We examined apparent weekly survival data of wild‐hatched Whooping Crane chicks collected via aerial and ground surveys using radio telemetry from 2006 to 2023. In this study, we explored relationships between chick survival and a host of potentially impactful predictor variables including parental experience, parental life history, habitat, ecoregion, weather, and climate, as well as nest and clutch characteristics using Cox Proportional Hazard Regression Models. Our results indicate that a chick without a sibling has an increased probability of survival. Survival probability also increased with collective parental experience and warm days (> 32°C) during the first 4 weeks after hatch. Our data indicate that parental experience is a reliable predictor of recruitment. Adult survival may therefore be indirectly linked with low chick survival as experienced adults are too often lost from this population. Additionally, our results suggest that efforts to collect a single egg from two‐egg nests may improve weekly survival of Whooping Crane chicks. The reintroduced Eastern Migratory Population (EMP) of Whooping Cranes (Grus americana) has experienced recruitment rates lower than what is needed for a self‐sustaining population due to high colt mortality. We examined weekly survival data of wild‐hatched Whooping Crane colts from 2006 to 2023 and explored relationships with predictor variables including parental experience, habitat, ecoregion, weather, and nest or clutch characteristics. Whether a colt had a sibling, if parents had more experience raising young, and warm days during the first 4 weeks after hatch were reliable predictors of crane colt survival.

Reintroductions aim to re-establish a viable population within the indigenous range of living organisms, especially of threatened species. The population of the Asian Crested Ibis Nipponia nippon, a well-known ‘Endangered’ bird species, has increased over 100 times since wild populations were rediscovered in 1981, and several reintroduction projects were subsequently carried out in its former range. An experimental release of the Asian Crested Ibis was conducted in Qianhu National Wetland Park located in the southern part of the Loess Plateau, China. It is vitally important to monitor released birds (at least their survival and breeding), to inform subsequent releases in other suitable sites. During extensive post-release monitoring, data on capture-recapture and reproductive status were obtained using banding, radiotelemetry, and field observations. Using the Cormack-Jolly-Seber (C-J-S) model, the average annual survival rates were estimated to be 0.569 (95% CI: 0.353–0.762) for released individuals and 0.643 (95% CI: 0.038–0.987) for all individuals. From 2014 to 2018, a total of 14 breeding pairs produced 28 eggs and 10 fledglings with successful reproduction of the second generation. The mean clutch size was 2.07 ± 0.25 (n = 29), and the breeding success was 34.5%. Predation and poor habitat quality have been shown to be the main factors affecting the reintroduced population at establishment stage. Some management suggestions at the metapopulation and ecosystem levels, including further release, predator control and habitat improvement, have been proposed.

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  = 102) over 9 years, individuals’ breeding dispersal probability in relation to age, sex, and reproductive success was analyzed 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 ± 164 m vs 210 ± 127 m). Crested Ibis exhibited a female-biased dispersal pattern that the mean dispersal distance 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.

2021年9—11月，对河南董寨国家级自然保护区再引入朱鹮（Nipponia nippon）的分布区和潜在分布区进行调查，共发现游荡期夜宿地17个，分布在河南罗山县12个、浉河区1个、光山县砖桥镇1个和湖北大悟县1个，11月朱鹮利用夜宿地15个。对这些夜宿地同步开展野外朱鹮种群数量调查，共统计到268只，其中84.33%的朱鹮种群分布在罗山县。最大夜宿集群数量为46只，集群超过15只的10个夜宿地停歇的朱鹮数量占总数的80.22%。结果表明，罗山县是再引入朱鹮的主要分布地，部分种群已出现向周边其他地区活动迁移和跳跃式向外扩散的现象。野外朱鹮种群中当年出生的幼鸟数量占20.52%，截至秋冬季，朱鹮幼鸟存活率为77.78%。建议加强管理保护区以外的朱鹮栖息地，尤其是再引入朱鹮的新扩散、新迁移地。同时，应与当地相关部门合作，优化朱鹮联合保护措施，对研究朱鹮习性特征，促进再引入朱鹮种群的扩大和复壮有重要意义。

We investigated potential effects of nest site and landscape scale factors, including anthropogenic disturbance and habitat patchiness, on the nesting success of a reintroduced population of northern aplomado falcons {Falco femora/is septentrionalis) in southern Texas. We monitored 62 nesting attempts during 2002-2004 in the Lower Rio Grande Valley. We developed hierarchical models describing daily nest survival rates (DSR) and compared the models using a Bayesian approach in R and WinBUGS. We considered possible effects of nest age, temporal trends, nest site variables, landscape structure, territory (a random effect), and 3 measures of anthropogenic disturbance: distance to paved road, proximity to power pole, and nocturnal light intensity. Whether evaluated by Deviance Information Criterion (DIC) scores or the models' overall posterior probabilities as estimated with a reversible jump Markov Chain Monte Carlo algorithm, none of our landscape or disturbance measures affected DSR. Rather, variation in DSR was best described by nest height, overhead cover, and nest source (artificial or natural). These nest site level factors may be manipulated by managers through provision of artificial nests. We recommend that artificial nests continue to be provided, as such nests are highly successful when located on moderately tall substrates, and they permit researchers to access nest contents for population monitoring.

During the last century, otter populations in the Mediterranean area of the Iberian Peninsula were dramatically reduced and disappeared in many localities. A reintroduction programme was established in north-eastern Spain (Muga and Fluvià basins and the “Aiguamolls de l'Empordà” wetlands), by releasing 42 otters from four different Iberian populations, between 1995 and 2002. In order to evaluate the success of the reintroduction programme, we investigated microsatellite variation in the native populations of released otters as well as in the population present in the release area in 2004. We used non-invasively collected samples as the DNA source to avoid disturbing the animals in the wild. Laboratory procedures included the screening of samples and a multiple-tubes approach to detect and correct genotyping errors. Our results show that founders have been replaced by descendants in the release area and the population is in Hardy-Weinberg equilibrium, with a 1:1 sex ratio. Western Iberian otters--representing two-thirds of the founder group and released earlier--have greatly contributed to the genetic composition of the current population. The genetic patterns of otters found in a basin north of the studied area suggest a common origin with the released population. We also detected in a few otters the presence of alleles not identified in the original founder group, and we shall discuss the possible origin of these alleles.

This chapter contains sections titled: Summary Introduction Methods Results and discussion General discussion Acknowledgements References

Intestinal microbiota play an important role in the survival of the host. However, no study to date has elucidated the adjustment of intestinal microbiota of the host during rewilding. Thus, this study aims to describe the intestinal bacterial community of reintroduced Przewalski’s horse (RPH) after being released into their original habitat for approximately 20 years in comparison with that of captive Przewalski’s horse (CPH), sympatric domestic horse (DH) and Mongolian wild ass (MWA) by sequencing the 16S rRNA gene. The results showed that the prevalent bacterial communities were different among CPHs, RPHs, DHs and MWAs at the family level. NMDS and ANOSIM analysis showed that the pattern of bacterial community composition in captive equines was distinct from that in the wild groups. It is shown that some bacteria had significant differences among different taxa (p < 0.001), such as Firmicutes, Bacteroidetes, Armatimonadetes, Clostrida, Bacteroidia, Clostridiales, Bacteroidales, Rikenellaceae and Bacteroidales_UCG-001. These bacteria were associated with the transition from in captive to in the wild (CPH and RPH), which reflected the change of environmental conditions. Meanwhile, Proteobacteria, Clostridia, Bacilli, Negativicutes, Gammaproteobacteria, Clostridiales, Bacillales, Selenomonadales, Pseudomonadales and Planococcaceae were the changed groups among RPHs, MWAs and DHs, which are related to feeding habits and diseases. Our results clearly showed the differences between intestinal microbiota in reintroduced animals and wild animals and led us to understand the survival state of reintroduced animals in the wild.

Habitat conversion for agriculture is a major driver of biodiversity loss, but our understanding of the demographic processes involved remains poor. We typically investigate the impacts of agriculture in isolation even though populations are likely to experience multiple, concurrent changes in the environment (e.g. land and climate change). Drivers of environmental change may interact to affect demography, but the mechanisms have yet to be explored fully in wild populations. Here, we investigate the mechanisms linking agricultural land use with breeding success using long‐term data for the formerly Critically Endangered Mauritius kestrel Falco punctatus, a tropical forest specialist that also occupies agricultural habitats. We specifically focused on the relationship between breeding success, agriculture and the timing of breeding because the latter is sensitive to changes in climatic conditions (spring rainfall) and enables us to explore the interactive effects of different (land and climate) drivers of environmental change. Breeding success, measured as egg survival to fledging, declines seasonally in this population, but we found that the rate of this decline became increasingly rapid as the area of agriculture around a nest site increased. If the relationship between breeding success and agriculture was used in isolation to estimate the demographic impact of agriculture, it would significantly under‐estimate breeding success in dry (early) springs and over‐estimate breeding success in wet (late) springs. Analysis of prey delivered to nests suggests that the relationship between breeding success and agriculture might be due, in part, to spatial variation in the availability of native, arboreal geckos. Synthesis and applications. Agriculture modifies the seasonal decline in breeding success in this population. As springs are becoming wetter in our study area and since the kestrels breed later in wetter springs, the impact of agriculture on breeding success will become worse over time. Our results suggest that forest restoration designed to reduce the detrimental impacts of agriculture on breeding may also help reduce the detrimental effects of breeding late due to wetter springs. Our results therefore highlight the importance of considering the interactive effects of environmental change when managing wild populations.

1. Spatial variation in habitat quality and its demographic consequences have important implications for the regulation of animal populations. Theoretically, habitat quality is typically viewed as a single gradient from `poor' to `good', but in wild populations it is possible that there are multiple environmental gradients that determine spatial variation in demography. 2. Understanding environmental gradients is important to gain mechanistic insights into important population processes, but also to understand how populations might respond to environmental change. Here, we explore habitat and elevation gradients and their implications for population persistence using detailed long-term data on 600 individuals of the Mauritius kestrel. These data allow us to statistically separate spatial variation in demography from variation arising out of individual or environmental quality and explore its relationships with habitat and topography. 3. Birds that breed earlier in the season have higher reproductive success, and we found that the timing of breeding varies significantly between territories. This variation is primarily driven by elevation, with birds breeding progressively later as elevation increases. 4. Pre-fledging survival from the egg to fledgling stage (independently of timing), and recruitment, also varied significantly between territories. This variation is driven by the habitat surrounding breeding sites with increasing agricultural encroachment causing survival and recruitment to decline. 5. Taken together, our results suggest that there are likely to be multiple environmental gradients affecting spatial variation in productivity in wild populations, and hence multiple and different routes through which environmental change might have consequences for population dynamics by modifying spatial processes.