Reintroduction Programs Research Articles

Shifts in ecosystem equilibria following trophic rewilding

AbstractAimTrophic rewilding is proposed as an approach to tackle biodiversity loss by restoring ecosystem dynamics through the reintroduction of keystone species. Currently, evidence on the ecological consequences of reintroduction programmes is sparse and difficult to generalize. To better understand the ecological consequences of trophic rewilding, we simulated the extinction and reintroduction of large‐bodied mammals under different environmental conditions.LocationEurope.MethodsWe selected four locations varying in productivity and seasonality in Europe and used a general ecosystem model called Madingley to run simulations. We initialized the model using body mass limits of a European Holocene baseline; we then removed large mammals and let the model converge to a new equilibrium. Next, we reintroduced the previously removed groups to assess whether the equilibrium would shift back to the initial condition. We tested three different reintroduction scenarios, in order to disentangle the importance of the different large mammal groups.ResultsThe removal of large‐bodied mammals led to cascading effects, mainly resulting in increases in smaller‐bodied herbivores and the release of mesopredators. Post‐reintroduction, the system's new equilibrium state was closer to the initial equilibrium for stable and productive locations compared to highly seasonal and low‐productive locations. The maximum trait space volume of the initial state and the post‐reintroduction state varied by 9.1% on average over all locations, with an average decrease in trait combinations of 6.6%. The body mass distribution differed by 28%, comparing the initial state to the post‐reintroduction state.Main ConclusionsOur simulation results suggest that reintroducing locally extinct large‐bodied mammals can broadly restore shifts in ecosystem structure, roughly resembling the baseline ecosystem conditions. However, the extent to which the ecosystem's state resembles the original ecosystem is largely dependent on the reintroduction strategy (only herbivores and omnivores vs. also carnivores) and timing, as well as local environmental conditions.

Seed dormancy, viability and germination of Illicium griffithii: A threatened medicinal plant of northeast India

Illicium griffithii Hook. f. & Thoms. is a threatened medicinal plant of North East India with low natural population. Field observation showed that the seeds remain dormant for 4–5 months and even after germination it fails to convert into saplings due to biotic interference. In the present study, various physical and chemical tests were conducted to overcome dormancy. The study revealed that the seeds of I. griffithii exhibited simple morpho-physiological dormancy reducing the germination percentage. Chemical scarification with 95 % H2SO4 for 5 min helped to overcome mechanical restriction of the endosperm and seed coat and resulted in high germination (80.5 %). Pre-treatment of the seeds with cold stratification for 60 days or application of gibberellic acid (GA3: 2000 mgl−1) effectively broke seed dormancy. Seeds stored at 5 °C (in moist sand) exhibited a minimum viability of 40 %, but all seeds stored dry at room temperatures and moist at 25 °C died. This study on seed germination would be helpful for mass multiplication of the species for reintroduction programmes including ex situ conservation that would aid in improving the subsistence economy of the local indigenous communities.

Combining a novel outplant module with metareplication to further abalone restoration capacity in California

ABSTRACT Species reintroductions require large resource investments for rearing and placement and are further complicated by the paucity of robust monitoring regimes. Nonetheless, continued population declines in many species necessitate such actions. The white abalone (Haliotis sorenseni) in California has experienced steep population declines and a reintroduction programme through outplanting juvenile, captive-bred abalone is considered necessary for its recovery. A novel module known as the Short-term Abalone Fixed Enclosure (SAFE) was developed to allow red abalone (H. rufescens), a surrogate species that is not endangered and co-occurs with white abalone, a period of adjustment before dispersing. Outplant events were conducted at multiple sites in California, USA and monitored regularly for shells and live animals in a process known as metareplication, considered essential for robust outplant reporting. Time-lapse cameras were also placed on SAFEs to document predator visitation. Live animals and shells both increased on-site throughout the first six months and declined thereafter, with most animals unaccounted for. Empty shells on site were considered a proxy for the mortality rate and the lack of encounters after a short period suggests successful emigration from modules into the reef habitat. Predator visitation was generally low, and no significant differences were found across outplant periods. Results from this study indicate outplant mortality may peak early and predator activity is generally low and unrelated to abalone introduction. This vital step illustrates this outplant method may be an effective tool in restoring abalone to subtidal rocky reefs.

Abundance and habitat suitability of Siamese crocodiles (Crocodylus siamensis, Schneider 1801) in Phetchaburi River, Kaeng Krachan National Park, Thailand

Abstract. Chanpradub K, Pattanawibool A, Saisamorn A, Bhumpakphan N, Chanthana S, Thongsong C, Ouansing Y, Suksawate W, Sukmasuang R. 2023. Abundance and habitat suitability of Siamese crocodiles (Crocodylus siamensis, Schneider 1801) in Phetchaburi River, Kaeng Krachan National Park, Thailand. Biodiversitas 24: 4755-4765. The Siamese crocodile (Crocodylus siamensis, Schneider 1801) is one of the critically endangered species with a remnant population reported in Kaeng Krachan National Park. This study aimed to investigate Siamese crocodiles' abundance and habitats along the Phetchaburi River. Thirteen rafting trips from December 2021 to July 2023 were conducted at a total distance of 315 kilometers, recording 68 encounters with an encounter rate of 0.22 per kilometer. It was estimated that the population size of Siamese crocodiles was four individuals. Environmental factors that influenced crocodile distribution, with slope, elevation, forest types, cumulative flow rates upstream, and land use patterns, were identified. These findings underscore the significance of the Phetchaburi River area for freshwater crocodile conservation, as indicated by a highly reliable model with a reliable score of 0.99±0.02. Important recommendations include habitat protection, development of a crocodile threat surveillance system, ongoing population studies, and community involvement, which are essential for sustainable conservation practices, public awareness campaigns, captive breeding and reintroduction programs, and population restoration efforts. This research provides valuable insights into the habitats and environmental factors impacting Siamese crocodiles, highlighting the critical role of preserving Kaeng Krachan National Park as an important habitat for this species.

Urgent propagation of the endemic and possibly extinct in the wild tree Cassine koordersii (Celastraceae)

Cassine koordersii Kosterm. (Celastraceae) is a narrow endemic tree species known only to Mt. Puger, Jember, Indonesia. The IUCN Red List classifies it as Critically Endangered (CR) possibly extinct in the wild. Currently, there are only two living collections at the Bogor Botanic Gardens. As an urgent measure to anticipate extinction, vegetative propagation through shoot cuttings was conducted. This study aimed to determine the effects of rooting media and Rootone-F hormone on the successfulness of shoot cuttings of C. koordersii. It was carried out at the glass house in April 2022 with a 3-months observations period. The Komatsu-FORDA Fog Cooling (KOFFCO) system was adopted. The research used a completely randomized factorial design with rooting media and Rootone-F hormone as treatments. The media were sand (M1), cocopeat+burnt husk 2:1 (M2), and perlite+vermiculite 1:1 (M3). The Rootone-F hormone treatments included control (R1) and the addition of Rootone-F (R2). Six treatment combinations and four replications by 12 units obtained a total of 288 cuttings. The results indicate that in general, M2 and R2 have the best average yield: percentage of rooted cuttings (14.58%), number of primary roots (1.7), primary root length (1.58 cm), and percentage of survival cuttings (78.12%). The interaction between rooting media and Rootone-F hormone was not significant for all parameters. Despite only few new individuals are generated, they are valuable material for ex-situ collection backup. In addition, new juvenile seedlings are designed as mother trees for clonal orchards. Their high percentage rooting is expected to support the reintroduction program to their natural habitats.

The Assessment of Animal Personality and Its Uses for Improving Zoo Animal Welfare

Abstract Animal welfare is central to the three aims of the modern zoo: conservation, research and education. Good welfare depends not only on the management of the captive population as a whole but also on the management and husbandry of individual animals. Zoo keepers are able to reliably assess animal personality traits, and these traits are linked to measures of welfare such as reproductive success, stereotypic behaviour and physiological stress. Assessing animal personality can help to address some of the challenges faced in zoo animal management. A validated personality questionnaire is a valuable tool for zoo professionals, as it can be used to predict reproductive success and the cohesion of social groups. Knowledge of animal personality can help keepers to devise management plans for individuals, and improve keeper safety as well as animal welfare. Aspects of individuals’ behaviour can affect the success of reintroduction programmes, so information about personality can also contribute to ex-situ conservation. Information © The Author 2023

Gut microbiome as a key monitoring indicator for reintroductions of captive animals.

Reintroduction programs seek to restore degraded populations and reverse biodiversity loss. To examine the hypothesis that gut symbionts could be used as an indicator of reintroduction success, we performed intensive metagenomic monitoring over 10 years to characterize the ecological succession and adaptive evolution of the gut symbionts of captive giant pandas reintroduced to the wild. We collected 63 fecal samples from 3 reintroduced individuals and 22 from 9 wild individuals and used 96 publicly available samples from another 3 captive individuals. By microbial composition analysis, we identified 3 community clusters of the gut microbiome (here termed enterotypes) with interenterotype succession that was closely related to the reintroduction process. Each of the 3 enterotypes was identified based on significant variation in the levels of 1 of 3 genera: Clostridium, Pseudomonas, and Escherichia. The enterotype of captive pandas was Escherichia. This enterotype was gradually replaced by the Clostridium enterotype during the wild-training process, which in turn was replaced by the Pseudomonas enterotype that resembled the enterotype of wild pandas, an indicator of conversion to wildness and a successful reintroduction. We also isolated 1 strain of Pseudomonas protegens from the wild enterotype, a previously reported free-living microbe, and found that its within-host evolution contributed to host dietary adaptation in the wild. Monitoring gut microbial structure provides a novel, noninvasive tool that can be used as an indicator of successful reintroduction of a captive individual to the wild.

Habitat Selection to Reintroduce Iris bismarckiana in Semi-Arid Environments

Conservation of endangered plant species in their indigenous regions is of crucial importance, especially for those grown in semi-arid regions. The objectives of this study were to explore the Nazareth iris’s (Iris bismarckiana) natural habitat and identify new suitable sites to initiate a reintroduction program of this endangered plant species in a semi-arid environment. The study was conducted in Dibbeen Forest Reserve, Jordan, where six zones inside the reserve [A–F] were assessed in addition to zone G outside the reserve borders that represents the area where I. bismarckiana still exists. Habitat selection variables (topography, soil physical and chemical properties, climatic data, and potential risks and benefits) from all zones within the reserve were cross matched with that of zone G. The results showed that climatic data of all selected sites were suitable for reintroduction; all sites are open to direct sunlight most of the day. The minimum soil depth was greater than 40 cm in all zones, while soil respiration level revealed that zone A (a recreation site) was below the recommended thresholds. The percentage of stone volume (>2 mm) in the soil profile was high in zones D and F. Zones E, C, and F were extremely steep (>40 degrees), which undermined their potential to be suitable habitats. All sites are susceptible to high human disturbance risk except zone B, which is protected and under continuous surveillance by the Reserve Botanist. Considering all measured suitability indicators, including slope degree suitability (<25), soil respiration (57–77 mg kg−1), soil stone percentage value (8.3%), tree canopy cover (open area), and human disturbance potential (low risk), zone B holds promise as a suitable site for a I. bismarckiana reintroduction program. Therefore, the initiation of long-term reintroduction programs within this site with timely surveillance is urgently needed to conserve and support such valuable species self-regeneration.

Contrasting genomic consequences of anthropogenic reintroduction and natural recolonization in high-arctic wild reindeer.

Anthropogenic reintroduction can supplement natural recolonization in reestablishing a species' distribution and abundance. However, both reintroductions and recolonizations can give rise to founder effects that reduce genetic diversity and increase inbreeding, potentially causing the accumulation of genetic load and reduced fitness. Most current populations of the endemic high-arctic Svalbard reindeer (Rangifer tarandus platyrhynchus) originate from recent reintroductions or recolonizations following regional extirpations due to past overharvesting. We investigated and compared the genomic consequences of these two paths to reestablishment using whole-genome shotgun sequencing of 100 Svalbard reindeer across their range. We found little admixture between reintroduced and natural populations. Two reintroduced populations, each founded by 12 individuals around four decades (i.e. 8 reindeer generations) ago, formed two distinct genetic clusters. Compared to the source population, these populations showed only small decreases in genome-wide heterozygosity and increases in inbreeding and lengths of runs of homozygosity. In contrast, the two naturally recolonized populations without admixture possessed much lower heterozygosity, higher inbreeding and longer runs of homozygosity, possibly caused by serial population founder effects and/or fewer or more genetically related founders than in the reintroduction events. Naturally recolonized populations can thus be more vulnerable to the accumulation of genetic load than reintroduced populations. This suggests that in some organisms even small-scale reintroduction programs based on genetically diverse source populations can be more effective than natural recolonization in establishing genetically diverse populations. These findings warrant particular attention in the conservation and management of populations and species threatened by habitat fragmentation and loss.

Adaptive Genetic Management of a Reintroduction Program from Captive Breeding to Metapopulation Management of an Arboreal Marsupial

The application of genetic data to conservation management programs can be hindered by the mismatch in timelines for management decisions and the acquisition of genetic data, particularly genomic sequence data that may require outsourcing. While applying genetic principles where data are absent can provide general guidelines for actions, genetic data can often fine-tune actions through adaptive management. We describe the adaptive genetic management of the establishment of a metapopulation of a small arboreal marsupial, the red-tailed phascogale (Phascogale calura). Two captive breeding programs were established as source populations, with genetic principles applied to the establishment of the first program and empirical genetic data used to guide the establishment of the second program. Genetic data from both programs were then used to allocate founders to three new populations to create a metapopulation with diversity both within and among the sites. Building and maintaining the diversity of metapopulations when recovering threatened species will reduce pressure on the original source populations and increase the resilience of the species.

Zoo-bred female birds prefer songs of zoo-bred males: Implications for adaptive management of reintroduction programs

Understanding the factors affecting the success of animal reintroductions is crucial for facilitating endangered species recovery. Cultural differences between individuals from different animal populations can lead to assortative mating, whereby individuals prefer to breed within their own familiar cultural cohort. Assortative mating can hinder the assimilation of zoo-bred individuals into wild populations, so quantifying this risk becomes important for informing adaptive management strategies in conservation. We conducted mate choice experiments on zoo-bred female regent honeyeaters (Anthochaera phrygia) to assess whether they showed stronger behavioural responses to the familiar but abnormal songs of zoo-bred male regent honeyeaters than those of their wild counterparts or an interspecific control song. Female regent honeyeaters were no more likely to enter the playback aviary in response to the songs of zoo-bred males than those of wild males or a different species. However, females that did enter the playback aviary were significantly more likely to respond quickly, approach the speaker closely and remain in the playback aviary for longer in response to the songs of zoo-bred males than wild songs or control songs. Our study is the first to show experimentally that zoo-bred females prefer familiar, but abnormal, zoo-bred songs over unfamiliar wild-type songs. We suggest that assortative mating amongst released birds is a risk in reintroduced regent honeyeaters, given recent evidence that the breeding success of reintroduced pairs is low. Our study demonstrates how small-scale experiments conducted within applied zoo-breeding settings can yield useful information to refine husbandry techniques and reduce cultural divides between wild and reintroduced populations.

Analyzing captive breeding outcomes to inform reintroduction practice: lessons from the pookila (Pseudomys novaehollandiae).

Captive breeding is often used to produce individuals for reintroduction programs in order to reestablish a species in an area where it has become locally extinct. To maximize the likelihood of establishing a self-sustaining population in the wild, an analysis of data from captive breeding programs is commonly undertaken to (1) increase the quantity of individuals and rate at which they can be released, and (2) maintain or improve the genetic and phenotypic quality of individuals. Here we demonstrate how the knowledge gained from these analyses can also be applied to decision-making during the design of subsequent reintroductions to further advance a reintroduction program toward success. We conducted an analysis of data from a captive breeding program for the threatened pookila (Pseudomys novaehollandiae, New Holland mouse) spanning 6 years. We found evidence for relationships between the reproductive output of pookila and behavioral, demographic, experiential, health, and physiological predictors. Based on a biological interpretation of these results, and with reference to a checklist of all known translocation tactics, we recommend 11 specific design elements to maximize the probability of pookila reproduction postrelease (thereby improving the likelihood of reintroduction success). These recommendations should be interpreted as hypotheses to be evaluated and refined in future reintroduction trials for the pookila. The uncertainty around the postrelease survival and reproduction of a species that is common in reintroduction practice warrants the creative use of existing data to inform adaptive management. Indeed, there is a wealth information in well-kept captive breeding records that is currently underused by reintroduction practitioners. The direct integration of knowledge derived from captive breeding (where available) with decision-making for reintroductions, as described here, will help navigate these uncertainties, which would benefit the conservation of both understudied and well-known species around the world.

Assessing the Movements, Habitat Use, and Site Fidelity of the Giant Freshwater Whipray (Urogymnus polylepis) with Acoustic Telemetry in the Maeklong River, Thailand

We used acoustic telemetry to assess site fidelity, movement patterns, and habitat use within the lower Maeklong River, Thailand, by 22 giant freshwater whipray Urogymnus polylepis. This study is the first of its kind for this rare, endangered species, and it begins to fill critical information gaps about its ecology and life history. Study animals were tagged subcutaneously in the dorsal area with acoustic transmitters and tracked for 12 months using a fixed array of eight receivers. Receivers were positioned within an 18 rkm section of the Maeklong, starting approximately 4 rkm upstream from the mouth. We calculated individual residency indices, tracked longitudinal movements, and assessed annual and seasonal patterns of site use. We also investigated spatial use patterns, diel activity patterns, and relationships of temperature and site fidelity. We detected 86% of our tagged whiprays, 53% of which were detected for the majority of the study period. Whiprays exhibited high site fidelity across seasons. Individuals made long longitudinal movements within the site for much of the study period but seemed to remain closer to the estuary during the second half of the rainy season and early winter. All receivers had large numbers of detections, but upstream receivers were visited for longer time durations than downstream receivers. A receiver in the middle of the study area had the highest detection rate, but low detection durations, suggesting that this receiver is in a migration corridor. A mix of immature and mature males and females was present in the site throughout the study period, suggesting that this area is not exclusively a breeding or nursery site. However, the high site fidelity suggests that this is an important aggregation site for the species. Effective conservation measures may include conservation zones and a shrimp reintroduction program upstream, ensuring fish passage through the middle of the site, and regulating traffic and pollution downstream. We found acoustic telemetry to be an effective study method and encourage its use to improve understanding of the giant freshwater whipray.

The history of the Atlantic sturgeon, Acipenser oxyrinchus Mitchill, 1815, in the Warta River of Central and Western Poland in the nineteenth century based on Polish sources

Abstract An analysis of Polish historical sources indicates that there are no references to sturgeon in the Warta River basin before 1810. It is hypothesized that there was no autochthonic sturgeon population in this river in historic times. The occasional occurrence of fish in the Warta River stemmed from their straying from the Oder River, especially during high waters. The situation changed in the second half of the nineteenth century because increasing pollution in the Oder River meant increasing numbers of fish entered the Warta River. Peak catches by fishers in Poznań were in the 1880s and early 1890s, after which the population collapsed and never recovered. Overfishing in this period stemmed primarily from the effects of regulating the Warta River for navigation. The data presented herein might have implications for the current sturgeon reintroduction program being conducted in the Warta River basin.

Challenges in the conservation of endangered Rucervus eldii eldii McClelland in Keibul Lamjao National Park and Pumlen pat: an analysis of sediment and water quality of the floating natural habitats in the Indo Burma hotspot.

As a part of the monitoring practice of the lone natural habitat of the endemic and endangered Rucervus eldii eldii McClelland or Sangai, the paper reports sediment and water characteristics of Keibul Lamjao National Park-the only floating national park of the world in Manipur, Indo Burma hotspot. The water analysis showed low pH (5.69 ± 0.16), high electrical conductivity (342 ± 13.01 μS m-1), high turbidity (33.2 ± 9.407 NTU), and high phosphate concentrations (0.92 ± 0.11mg L-1) during the study period. The water quality index values calculated indicate that the park water during post-monsoon season is unfit for drinking. Thus, the degrading water quality poses a serious risk to the health of the deer and other species in the park. At present, Sangai in its natural habitat is threatened by pollution, encroachment, phoomdi thickness reduction, and inbreeding depression. To address the problem of inbreeding, Pumlen pat is considered as a second suitable natural habitat for the deer reintroduction program. During the study, water characteristics of the wetland showed similar characteristics as KLNP, i.e., low pH (5.86 ± 0.30), high electrical conductivity (377.6 ± 5.55 μS m-1), high turbidity (32.36 ± 4.91 NTU), and high phosphate concentrations (0.79 ± 0.14mg L-1). Likewise, sediments showed high TP accumulation that ranged from 197.03 ± 0.75 to 332.88 ± 0.99mgkg-1 for KLNP and 245.18 ± 0.85 to 351.48 ± 0.71mgkg-1 for Pumlen pat, respectively. Both, the lone natural habitat and the proposed habitat showed deteriorating water quality. As such, continuous monitoring of KLNP and Pumlen pat water and sediment quality should be a priority during the management practices to protect the endangered deer and health of the habitats for long-term conservation.

Reproductive cycles of alligator snapping turtles (Macrochelys temminckii)

The alligator snapping turtle (Macrochelys temminckii) is a species for which captive propagation and reintroduction programs are well established; however, little is known about its reproductive behavior and physiology. In this study, we measured monthly plasma sex steroid hormone concentrations of androgen (T + DHT) estradiol-17B (E2), and progesterone (P4), and used ultrasonography to monitor annual reproductive cycles of a captive population of alligator snapping turtles that is maintained under semi-natural conditions in southeastern Oklahoma. Concurrently, we used automated radio telemetry to measure the relative activity levels of male and female alligator snapping turtles and examine these activity patterns in the context of their reproductive cycles. We also measured monthly concentrations of the glucocorticoid (GC) corticosterone (CORT). Seasonal variation was only detected for T in males, but was observed for T, E2, and P4 in females. Vitellogenesis began in August and ended in April and coincided with elevated E2. Ovulation took place 10–29 April and the nesting period lasted from 11 May – 3 June. Males exhibited greater relative activity levels than females in the fall, winter, and early spring, which coincided with the period when mature sperm would be available for mating. Females were more active than males during the peri-nesting period in the spring. Seasonal changes in CORT were detected and did not differ between males and females. CORT concentrations were elevated in the late spring and summer, coincident with the foraging season, and depressed in the fall, and winter, and at their nadir in the early spring.

Captivity, Reintroductions, and the Rewilding of Amphibian-associated Bacterial Communities.

Many studies have noted differences in microbes associated with animals reared in captivity compared to their wild counterparts, but few studies have examined how microbes change when animals are reintroduced to the wild after captive rearing. As captive assurance populations and reintroduction programs increase, a better understanding of how microbial symbionts respond during animal translocations is critical. We examined changes in microbes associated with boreal toads (Anaxyrus boreas), a threatened amphibian, after reintroduction to the wild following captive rearing. Previous studies demonstrate that developmental life stage is an important factor in amphibian microbiomes. We collected 16S marker-gene sequencing datasets to investigate: (i) comparisons of the skin, mouth, and fecal bacteria of boreal toads across four developmental life stages in captivity and the wild, (ii) tadpole skin bacteria before and after reintroduction to the wild, and (iii) adult skin bacteria during reintroduction to the wild. We demonstrated that differences occur across skin, fecal, and mouth bacterial communities in captive versus wild boreal toads, and that the degree of difference depends on developmental stage. Skin bacterial communities from captive tadpoles were more similar to their wild counterparts than captive post-metamorphic individuals were to their wild counterparts. When captive-reared tadpoles were introduced to a wild site, their skin bacteria changed rapidly to resemble wild tadpoles. Similarly, the skin bacterial communities of reintroduced adult boreal toads also shifted to resemble those of wild toads. Our results indicate that a clear microbial signature of captivity in amphibians does not persist after release into natural habitat.

Impact of environmental variables on some reproductive metrics of white-lipped peccaries (Tayassu pecari) raised in Atlantic Forest of Brazil

Knowledge on male reproductive physiology is essential for the development of effective conservation strategies. This study investigated the influence of environmental variables on certain reproductive metrics in white-lipped peccaries (Tayassu pecari) raised in the Atlantic Forest. After anesthetization, testicular and cauda epididymis biometry were evaluated in nine adult male individuals subjected to electroejaculation. Semen was evaluated for volume, pH, concentration, total number of sperm, sperm morphology, membrane integrity, and kinematic parameters. Concurrently, environmental variables were collected from the day before, for the previous 14 days (estimated for sperm maturation in epididymis), and the period of 51–55 days (corresponding to the spermatogenic cycle) before semen collection. Overall, it was observed that rainfall is the most important environmental variable influencing the reproductive parameters of white-lipped peccaries, being positively correlated with the amplitude of lateral sperm head displacement (ρ = 0.62, P < 0.05) and the appearance of proximal cytoplasmic droplets in sperm (ρ = 0.62, P < 0.05). In addition, the testicular biometry of the species is influenced by the set of environmental variables of air temperature, rainfall, and relative humidity (ρ ≥ 0.60, P < 0.05). On the other hand, epididymal biometric data showed numerous correlations between cauda epididymis metrics and sperm parameters (ρ = 0.68, P < 0.05). This information will be useful to improving conservation strategies for these animals, contributing to their management in captivity and to reintroduction programs, especially in the Atlantic Forest where the species is declining.

Computer-assisted semen analysis in large falcons (Falco spp.) and comparison to results of conventional semen analysis

Numerous raptor species including some falcon species are facing continuous population decline in the wild and some are threatened by extinction. To support these species, captive breeding and reintroduction programs are attempted. Besides conservation, some large falcon species are commonly used in falconry and therefore bred commercially. Assisted reproduction is established in falcon breeding since the 1970s and semen analysis is an integral part to enable assessment of breeding males, inclusion or exclusion of semen donors and quality control of semen prior to artificial insemination. Conventional methods for semen analysis are widely used, but are time consuming and depend on the investigator's experience and ability. Computer-assisted semen analysis (CASA) would offer an objective, fast and reproducible alternative, but as they have not been established in large falcon species, this was the aim of this study. To this end, we examined in 3 breeding seasons 109 semen samples of gyr-saker hybrid falcons (n=2) and peregrine falcons (n=4) in 940 fields of view using the Minitube CASA SpermVision and compared these results to results of conventional methods of semen analysis. We used a preprogrammed setting and adapted two settings of CASA according to specific semen characteristics of falcons. Sperm velocity, motility and viability parameters were recorded successfully using CASA. Correlation of conventional and computer-assisted motility analysis improved during the process of adaptation of CASA settings, but both methods differed significantly due to misinterpretation of round bodies and semen impurities by CASA. Viability values of conventional and computer assisted viability analysis using SYBR-PI correlated significantly while sperm concentration did not at all. CASA failed to replace conventional semen analysis regarding sperm motility and sperm concentration using 3 different settings, as a reliable differentiation between spermatozoa, spermatids and round bodies was not achieved. Using CASA, sperm velocity parameters were measured in spermatozoa of captive-bred large falcons for the first time and may be used as orientation values.

Rewilding soil-disturbing vertebrates to rehabilitate degraded landscapes: benefits and risks.

Soil-disturbing animals are common globally and play important roles in creating and maintaining healthy functional soils and landscapes. Yet many of these animals are threatened or locally extinct due to habitat loss, predation by non-native animals or poaching and poisoning. Some reintroduction and rewilding programmes have as their core aims to increase animal populations and reinstate processes that have been lost due to their extirpation. Here we use a meta-analytical approach to review the effects of soil-disturbing vertebrates on ecosystem processes, and advance the argument that they can be used to rehabilitate degraded ecosystems by altering mainly composition and function, but with fewer positive effects on structure. We describe four examples where the loss or reintroduction of soil-disturbing vertebrates leads to ecosystem state changes and highlight the role of spatial scale, covarying management changes, and species co-occurrence in modulating their effects. We discuss the advantages and disadvantages of using soil-disturbing vertebrates over mechanized engineering approaches such as pitting and furrowing, considering some advantages to include more self-sustainable and heterogeneous disturbances, creation of new habitats and added recreational values. Finally, we identify key knowledge gaps in our understanding of the use of soil-disturbing vertebrates for rehabilitating degraded ecosystems.