Method of releasing and number of animals are determinants for the success of European ground squirrel (Spermophilus citellus) reintroductions

Phylogenomic insights into the polyphyletic nature of Altai falcons within eastern sakers (Falco cherrug) and the origins of gyrfalcons (Falco rusticolus)

The Altai falcon from Central Asia always attracted the attention of humans. Long considered a totemic bird in its native area, modern falconers still much appreciated this large-bodied and mighty bird of prey due to its rarity and unique look. The peculiar body characteristics halfway between the saker falcon (Falco cherrug) and the gyrfalcon (F. rusticolus) triggered debates about its contentious taxonomy. The weak phylogenetic signal associated with traditional genetic methods could not resolve this uncertainty. Here, we address the controversial evolutionary origin of Altai falcons by means of a genome-wide approach, Restriction-site Associated DNA sequencing, using sympatric eastern sakers falcons, allopatric western saker falcons and gyrfalcons as outgroup. This approach provided an unprecedented insight into the phylogenetic relationships of the studied populations by delivering 17,095 unlinked SNPs shedding light on the polyphyletic nature of Altai falcons within eastern sakers. Thus we concluded that the former must correspond to a low taxonomic rank, probably an ecotype or form of the latter. Also, we found that eastern sakers are paraphyletic without gyrfalcons, thus, these latter birds are best regarded as the direct sister lineage of the eastern sakers. This evolutionary relationship, corroborated also by re-analyzing the dataset with the inclusion of outgroup samples (F. biarmicus and F. peregrinus), put eastern sakers into a new light as the potential ancestral genetic source of high latitude and altitude adaptation in descendent populations. Finally, conservation genomic values hint at the stable genetic background of the studied saker populations.

Rise and fall: Results of a multidisciplinary study and 5-year long monitoring of conservation translocation of the European ground squirrel

The current publication gives a detailed assessment of the results from a population reinforcement of a European ground squirrel's (Spermophiluscitellus) colony in south-eastern Bulgaria. The reinforcement was planned and implemented along with multidisciplinary research of the adaptation process (including radiotelemetry, parasitological study and assessment of the stress in the animals) and regular monitoring (yearly burrow counting). Although the donor and recipient populations were genetically similar, morphometrical data indicated variations in the body size probably due to the difference in population densities in the two sites. The monitoring revealed that the burrows were aggregated and there was a positive correlation in the spatial distribution of the ground squirrels' burrow holes and the colonies of Harting's vole (Microtushartingi) - another social ground-digging rodent that co-inhabits the study area. The first results showed successful reinforcement according to the three classical evaluation criteria: the individuals survived the translocation process, they successfully reproduced and an initial population growth was observed, based on the burrow entrances' count - from 36 in 2017 to 280 in 2020. In 2021, however, a considerable decline in the abundance of the population was recorded - 58.5% decline in the burrow number and 36% decline in the colony area. A decrease was also observed in the abundance of the Harting's voles' colonies. A review of all the collected information suggests it is unlikely that the decrease is due to helminth parasites, translocation stress or other behaviour issues. The most probable explanation is the bad weather conditions - unusually high rainfalls combined with relatively high temperatures in January 2021. In conclusion, we strongly emphasise the need for detailed and long-term monitoring after conservation translocation and careful evaluation of all the influencing factors before, during and after such actions.

Influence of weather on the behaviour of reintroduced Przewalski’s horses in the Great Gobi B Strictly Protected Area (Mongolia): implications for conservation

Background

Reintroduction is a common technique for re-establishing threatened species. However, the adaptation to novel habitats with distinct conditions poses a risk of failure. Weather conditions affect the behaviour of animals, and thus, their adaptation to new conditions and survival. Reintroduced Przewalski’s horses living in Mongolia’s continental arid climate with extreme temperature and precipitation variability, serve as an ideal model species for studying the behavioural response of selected groups to these harsh conditions.

Methods

The research was conducted in The Great Gobi B Strictly Protected Area, Mongolia. In summer 2018, three groups were recorded (Azaa, Tsetsen and Mares18) involving 29 individuals. In Spring 2019, 4 groups were recorded (Azaa, Tsetsen, Hustai1 and Mares19) involving 34 individuals. In Autumn 2019, 4 groups were recorded (Azaa, Tsetsen, Hustai2 and Tanan) involving 35 individuals. Thirteen weather variables were recorded in 10-min intervals, together with the percentage representation of selected behavioural categories (feeding, locomotion, resting, and social). The effect of weather on behaviour was analysed through GLMM. Influence of the group-history factors (recently reintroduced, long-term reintroduced and wild-born) was also analysed.

Results

Feeding significantly increased with cloudy and windy conditions and was more frequent in autumn than spring and summer. Locomotion was positively explained by temperature and cloudiness and was higher in summer than spring and autumn. Resting behaviour decreased with altitude and cloudiness, and the dispersion of the group was lower when resting. Increased social interactions were observed with higher temperatures and were more frequent in summer compared to spring and autumn. Differences were found in the display of the behaviours among the selected harems, showing interesting patterns when grouping them according to their origin and experience.

Conclusions

Weather patterns seem to influence the behaviour of Przewalski’s horse. These results might assist in further management plans for the species, especially in the view of intensifying climate change and alteration of weather patterns. As previously suggested, after approximately 1 year, horses adapt to novel conditions and display the typical behavioural pattern of wild-born Przewalski’s horses.

European Ground Squirrels at the Edge: Current Distribution Status and Anticipated Impact of Climate on Europe’s Southernmost Population

The European ground squirrel (Spermophilus citellus) is an endangered semifossorial small mammal of grassland/agricultural ecosystems. In the last few decades, the species’ population has declined throughout its range in Europe. The Greek populations represent the southernmost limit of the species’ range and are notably small, scattered, and located mainly in human-modified areas. The goal of the present research is to understand the environmental and anthropogenic variables associated with its distribution in the Mediterranean habitats, assess possible drivers of observed local extinctions, and propose conservation and land-use management actions in light of near-future climate change scenarios. We used presence records since 2000 across all known populations (107 colonies) and maximum entropy conditional probability models (MaxEnt) to calculate both the habitat suitability (bioclimatic variables) and habitat availability (anthropogenic/land-use variables) within the European ground squirrel’s historical range in northern Greece. We report a projected 39% to 94.3% decrease in habitat suitability by 2040–2060 due to climate change. Based on our findings, we provide guidance by proposing nascent conservation actions to protect the few existing colonies in Greece via improved land management practices and identify in situ climate refugia that could be prioritized as sites for future reintroductions.

Richardson’s ground squirrels (Urocitellus richardsonii) are associated primarily with intermediate levels of grassland, clay loam soils, and human development in Canadian mixed-grass prairies

Richardson’s ground squirrel (Urocitellus richardsonii (Sabine, 1822)) is a widespread burrowing mammal on the northern Great Plains. This species is a prominent prey item for a variety of predators and its burrows provide important habitat for other wildlife; however, Richardson’s ground squirrel is also considered an economically damaging agricultural pest. Despite the ecological importance of Richardson’s ground squirrels and their status as pests, there are gaps in our knowledge about large-scale habitat associations for this species. In 2011 and 2012, we conducted 1840 roadside surveys in a 130 000 km2 area of southern Saskatchewan, Canada, to understand which habitat features are associated with Richardson’s ground squirrel occurrence. Ground squirrels were observed on 8% of the surveys. Probability of ground squirrel occurrence was highest in areas with moderate amounts of grassland (approximately 30%), areas that were developed by humans (>30%), and had a high proportion of clay loam soils, presumably for burrowing. Our study highlights the importance of heterogeneous landscapes and that areas disturbed by humans may provide suitable vegetation structure for ground squirrels. This information can help to identify important habitat for species that rely on Richardson’s ground squirrels and identify areas where Richardson’s ground squirrels could come into conflict with agriculture.

Translocations of European ground squirrel (Spermophilus citellus) along altitudinal gradient in Bulgaria – an overview

The European ground squirrel (Spermophiluscitellus) is a vulnerable species (IUCN) living in open habitats of Central and South-eastern Europe. Translocations (introductions, reintroductions and reinforcements) are commonly used as part of the European ground squirrel (EGS) conservation. There are numerous publications for such activities carried out in Central Europe, but data from South-eastern Europe, where translocations have also been implemented, are still scarce.

The present study summarises the methodologies used in the translocations in Bulgaria and analyses the factors impacting their success. Eight translocations of more than 1730 individuals were performed in the period 2010 to 2018. These included 4 reinforcements, 3 reintroductions and 1 introduction. Two of the translocations are still ongoing. Five of the completed six (83%) translocations were successful, although in two cases the number of individuals was critically low. The relatively higher success in Bulgaria than in Central Europe is probably due to using the gained experience. Most of the translocations (6) used a soft release approach. In 6 cases, the animals settled 100 to 720 metres away from the release site, implying management and protection of suitable habitat beyond the translocation area. In 7 of the translocations, the altitude between the donor colony and the release site varied from 470 to 1320 m which could have a hindering effect on the adaptation of animals due to the specific conditions in the mountains. The main reasons for failure are probably poorly selected and maintained habitats and bad climatic conditions (rainy and cool weather) during the translocation action. European funds are of critical importance for translocations, with only two translocations funded by other sources. Based on the gathered data, the current paper also gives some recommendations for improvement in translocation activities.

Choice or opportunity: are post-release social groupings influenced by familiarity or reintroduction protocols?

The conservation benefits of maintaining social groupings during and after animal translocations are unclear. Although some studies report improved post-release survival, others found no discernible influence on reintroduction success. Understanding the effects of social groupings is difficult because release methods can influence the animals’ ability to maintain social groups. We explored this relationship by first studying whether release protocols influenced post-release cohesion in the communal burrowing bettong Bettongia lesueur, and then investigating whether maintenance of social cohesion conferred any post-release advantage. We released bettongs into a small (8 ha) and large (2,600 ha) area and compared the proportion that maintained social groupings in the different settings. The proportion of bettongs sharing with previous warren co-occupants was higher than expected by chance in both areas, however, a significantly higher proportion of bettongs maintained social groupings in the small (75%) compared to the large release area (13%). This suggests bettongs prefer to maintain social groupings but are unable to locate members of their group in large release areas. Bettongs that did maintain social groupings showed no difference in reproductive or health outcomes compared to those that formed new social groupings, suggesting no benefit to reintroduction success. We conclude that release protocols can influence post-release cohesion, but that greater cohesion does not necessarily confer advantages to group-living animals. To test the importance of social cohesion, further research on reintroductions should compare post-release parameters for animals released using protocols that do and do not facilitate maintenance of social groupings.

Soft-release versus hard-release for reintroduction of an endangered species: an experimental comparison using eastern barred bandicoots (Perameles gunnii)

Context Reintroduction is a popular tool for conserving endangered species, yet many attempts fail. Soft-release measures, including acclimatisation, have been used for many species around the world, based on the reasoning that gradual and supported reintroductions should improve the success of animals released into an unfamiliar wild environment. However, experimental testing of soft-release methods is rare. Aims To experimentally test the effect of a soft-release method versus a hard-release method on the initial reintroduction success of the eastern barred bandicoot (Perameles gunnii). Methods We released 12 captive-bred eastern barred bandicoots into a predator-proof reserve using two methods: soft-release (7 days of on-site acclimatisation with supplementary food before release) and hard-release (no acclimatisation and no supplementary food). We monitored the bandicoots intensively via radio-tracking and live-trapping for 4 weeks after release. Compared with hard-release bandicoots, we predicted that soft-release bandicoots would have (1) reduced movement (first night dispersal, site fidelity and activity range), (2) more directed patterns of habitat selection, (3) improved bodyweights and (4) improved survival. Key results There was no detectable difference in habitat selection, overall weight change and survival between the soft-release and hard-release groups. There was moderate evidence that, compared with the hard-release group, soft-release bandicoots moved less, demonstrated lower individual variation in all measures of movement, and lost weight more gradually after release. In most cases, effect sizes were moderate to large but had large standard errors owing to both small sample size and high variance. Consequently, statistical testing failed to detect significant differences at the 5% level. Conclusions Despite evidence that the release method influenced some of the monitored behaviours, soft-release did not confer a consistent and substantive advantage for captive-bred eastern barred bandicoots at our site. We conclude that soft-release is unlikely to improve overall reintroduction success for this species at fenced predator-free sites. Implications The present study suggests that the preferred option for reintroductions of eastern barred bandicoots to fenced sites is a hard-release, information that is now being used to guide reintroductions of this species. Similar experiments should be undertaken to improve reintroduction practice for other endangered species.

Tailoring release protocols to individual species and sites: one size does not fit all

Reintroduction programs for threatened species often include elaborate release strategies designed to improve success, but their advantages are rarely tested scientifically. We used a set of four experiments to demonstrate that the influence of release strategies on short-term reintroduction outcomes is related to both intrinsic and extrinsic factors. We compared different reintroduction strategies for three mammal species in an arid environment where exotic mammalian predators were removed. Wild greater stick-nest rats selected vegetation shelter sites with greater structural density than captive-bred rats, travelled further from the release site and experienced lower rates of mortality. In comparison, there was no difference in mortality or movement between wild and captive-bred greater bilbies. Burrowing bettongs and greater bilbies were also subjected to immediate and delayed release strategies and whilst no difference was detected in bilbies, bettongs that were subjected to delayed releases lost less weight and took less time to establish burrows than those that were immediately released. Interspecific differences in treatment response were attributed to predation risk, the nature of the release site, and behavioural traits such as shelter investment and sociality. Our varied results highlight the inadequacies of review articles focusing on optimum release protocols due to their attempt to generalise across species and release sites. We provide an example of a predictive model to guide future release strategy experimentation that recognises the range of intrinsic and extrinsic factors influencing reintroduction outcomes. We encourage researchers to treat programs experimentally, identify individual site and species characters that may influence release strategies and record data on movements, mortality, weight dynamics, and settling times and distances. The inherent issues of small sample size and low statistical power that plague most reintroduction experiments suggests there is also a need for increased standardisation and publication of data sets to enable appropriate meta-analyses to occur.

Boldness towards novelty and translocation success in captive-raised, orphaned Tasmanian devils

Translocation of endangered animals is common, but success is often variable and/or poor. Despite its intuitive appeal, little is known with regards to how individual differences amongst translocated animals influence their post-release survival, growth, and reproduction. We measured consistent pre-release responses to novelty in a familiar environment (boldness; repeatability=0.55) and cortisol response in a group of captive-reared Tasmanian devils, currently listed as "Endangered" by the IUCN. The devils were then released at either a hard- or soft-release site within their mothers' population of origin, and individual growth, movement, reproduction (females only), and survival across 2-8 months post-release was measured. Sex, release method, cohort, behavior, and cortisol response did not affect post-release growth, nor did these factors influence the home range size of orphan devils. Final linear distances moved from the release site were impacted heavily by the release cohort, but translocated devils' movement overall was not different from that in the same-age wild devils. All orphan females of reproductive age were subsequently captured with offspring. Overall survival rates in translocated devils were moderate (∼42%), and were not affected by devil sex, release method, cohort, release weight, or pre-release cortisol response. Devils that survived during the study period were, however, 3.5 times more bold than those that did not (effect size r=0.76). Our results suggest that conservation managers may need to provide developmental conditions in captivity that promote a wide range of behaviors across individuals slated for wild release.

Multilocus phylogeography of the European ground squirrel: cryptic interglacial refugia of continental climate in Europe

The theory of classical and cryptic Pleistocene refugia is based mainly on historical changes in temperature, and the refugia are usually defined within a latitudinal gradient. However, the gradient of oceanic-continental climate (i.e. longitudinal) was also significantly variable during glacial cycles with important biotic consequences. Range-wide phylogeography of the European ground squirrel (EGS) was used to interpret the evolutionary and palaeogeographical history of the species in Europe and to shed light on its glacial-interglacial dynamic. The EGS is a steppe-inhabiting species and the westernmost member of the genus in the Palaearctic region. We have analysed 915 specimens throughout the present natural range by employing mitochondrial DNA sequences (cytochrome b gene) and 12 nuclear microsatellite markers. The reconstructed phylogeography divides the species into two main geographical groups, with deep substructuring within both groups. Bulgaria is the centre of the ancestral area, and it also has the highest genetic diversity within the species. The northernmost group of the EGS survived in the southern part of Pannonia throughout several glacial-interglacial cycles. Animals from this population probably repeatedly colonized areas further to the north and west during the glacial periods, while in the interglacial periods, the EGS distribution contracted back to this Pannonian refugium. The EGS thus represents a species with a glacial expansion/interglacial contraction palaeogeographical dynamics, and the Pannonian and southeastern Balkanian steppes are supported as cryptic refugia of continental climate during Pleistocene interglacials.