Breeding Events Research Articles

Conspecific density and habitat quality affect breeding habitat selection: Support for the social attraction hypothesis

AbstractBreeding habitat selection is a critical component of the annual cycle because of its effect on fitness. Multiple theories of habitat selection can be differentiated by their responses to the quantity of habitat, conspecific density, and habitat quality. Here, we use network analysis to understand the characteristics of fine‐scale breeding habitat selected by both immigrant and returning adult piping plovers (Charadrius melodus) to test five hypotheses of habitat selection. Between 2014 and 2019, we recorded 2034 uniquely marked adults breeding at 326 breeding locations with 1240 successive breeding events. Among adults, immigration events (i.e., individuals that moved to a new breeding location) were detected as often as fidelity to the same breeding location. We found support for the social attraction hypothesis for both immigrants and returners, indicating that adult plovers use social cues for settlement decisions. Adult plovers selected habitats with intermediate levels of conspecific density and high habitat quality, as assessed by con‐ and heterospecific nest survival, with no effect from the amount of available habitat. We also simulated the loss of breeding habitat and identified highly connected breeding locations, which occurred mostly on the riverine habitat type, which have important implications for habitat conservation for this listed species. Our results highlight the role of conspecifics at identifying high‐quality breeding habitat regardless of whether individuals return to the same breeding site or immigrate to new areas.

Captive breeding in the endangered alpine tree frog, Litoria verreauxii alpina.

Amphibians are experiencing dramatic worldwide declines and many species are reliant on captive breeding programs to ensure continued survival. However, captive breeding in amphibians is not always successful because many species, especially ones in decline, have particular and specific breeding needs. The endangered alpine tree frog, Litoria verreauxii alpina, has never been bred in captivity before. Due to its dramatic declines across the Australian Alps caused by the global pandemic chytridiomycosis, the species is a potential candidate for captive assurance colonies, which rely on captive breeding. For this study we tested hormone induction using two hormones that have had some success in other amphibian species, to no avail. We then tried outdoor breeding mesocosms during the winter/spring at temperatures similar to their natural breeding season, which was successful. Sixty-five percent of the egg masses laid successfully hatched tadpoles. Females laid more than one clutch over the experiment indicating either a shorter than annual ovulation cycle, or that females are capable of partial ovulation during breeding events. Outdoor breeding mesocosms are a possibility outside the native climate of a species, provided that temperatures overlap with their natural environment. Here, we highlight that troubleshooting is essential before embarking on a captive breeding program of a species that has not been bred before. Hormonal induction of breeding is not always successful; therefore, outdoor mesocosms might be required to achieve healthy tadpoles.

Northern Shoveler Spatula clypeata: a possible first breeding record for Algeria

Breeding events of a waterbird species outside of their normal breeding grounds could be important to address how population changes on wintering areas are impacted by changes elsewhere in the birds’ annual cycle. In this note we confirm the first breeding record of Northern Shoveler Spatula clypeata in Algeria. The breeding site was a saline lake, Sebkhet El-mahmel, located 180 km from the Mediterranean Sea and subject to a semi-arid climate. The area was visited on 16 June 2019 and the species was confirmed as a pair of Northern Shoveler accompanied by eight juveniles. The Northern Shoveler is an unmistakable waterbird species in the northern hemisphere due to its distinctive bill. The female and her juveniles looked healthy and they spent almost the entire daytime foraging and swimming.

Fight, flight or bright(en)

When you think of colour-changing animals, what comes to mind? A slow-moving chameleon barely distinguishable from its spot in a tree? Or maybe an octopus camouflaging itself on the ocean floor? What about hundreds of bright yellow male Asian common toads (Duttaphrynus melanostictus) gathering to fight each other for the company of their somewhat drab, brown-coloured mates? During monsoon rains, the toads gather in groups of over 200 individuals at breeding sites throughout South and Southeast Asia. Before congregating, the male toads swiftly change colour to a conspicuous yellow, signalling to other males that they are ready to fight – and to distinguish themselves to potential female mates. Unsurprisingly, hormones associated with the ‘fight or flight’ response are high during these ‘explosive breeding’ events thanks to the stressful monsoon rains that coincide with the mating season and fighting for partners. Could these hormones have something to do with the toads’ striking colour change? Susanne Stückler and Doris Preininger from the University of Vienna, Austria, and their colleague Matthew Fuxjager from Brown University, USA, decided to investigate.The trio turned to a group of toads housed in Vienna Zoo, Austria, to see which hormones were responsible for the colour change. First, they measured the colour of the toads’ backs – specifically, the hue (what we normally think of when we describe colour), brightness (lightness or darkness) and chroma (colour saturation). Having established the toads’ baseline colour, the researchers tested whether a dose of the reproductive hormone human chorionic gonadotropin (hCG) could trick the toads into thinking that it was breeding season and trigger a rapid colour change. Surprisingly, the toads did not turn bright yellow when they experienced an increase in their reproductive hormone levels. If reproductive hormones such as hCG aren't triggering a change in colour, could the hormones associated with a stressful experience be driving the colourful transformation instead?To test this, the scientists gave the toads one of the stress hormones, either adrenaline (epinephrine) or noradrenaline (norepinephrine), and again recorded the toads’ hue, brightness and colour saturation. With either stress hormone, the toads became brighter and their shade of yellow became more saturated. Interestingly, for these toads, only a grape-sized patch of skin changed colour (about half the size of the body), and a few did not change colour at all.To make sure any colour changes the scientists saw in these treatments could actually be seen by potential mates (or sparring partners), Stückler and colleagues also calculated how noticeable the colour changes would be to the eyes of a toad. Using the colour perception data of a close relative, the common toad (Bufo bufo), the scientists were able to estimate just how different this stress-induced yellow would be from the typical brown colour of females or males – and indeed, the yellow stood out! The scientists suggest that to trigger the whole-body colour change, perhaps there are other hormones at play that they haven't tested yet. Or perhaps physical signals such as monsoon rains and social cues such as the company of other toads work together with stress hormones during explosive breeding events in the wild.This is the first time that stress hormones alone have been shown to cause animals to change colour rapidly without the help of other hormones that signal breeding. For Asian common toads, being a brighter, flashier yellow might make them more successful during these explosive breeding events, so it would make sense that they have embraced another means to quickly change colour. So, next time you think of colour-changing animals, perhaps you'll picture the bright yellow Asian common toad – and how their ‘fight or flight’ hormones have now been adopted for flashiness.

Survival vs. reproduction: dimorphic life history strategy in Heermann’s gulls during warm ocean temperature anomalies

Seabirds have thrived over time in marine environments with highly variable productivity. Life history strategies favored by natural selection consist of late sexual maturation, few offspring per breeding event, high adult survival, long lifespan, and deferred breeding when food availability is low. Heermann’s gull Larus heermanni, with 95% of its world population breeding on Isla Rasa, Gulf of California, follows this common pattern, including poor breeding performance during periods of low food availability often associated with high sea surface temperatures. Our interest was to characterize individual variations in this general pattern and assess its consequences for lifetime number of fledglings produced. We compared life history parameters from a set of known-age females banded during 1984-1993 and recaptured during 1989-2013 and found that most (85%) followed the general pattern (hereafter ‘conservative’) of laying ≤2 eggs and fledging no chicks during anomalously warm years. However, 15% of the females (hereafter ‘bold’) laid eggs during all anomalously warm years and fledged chicks in most of those years. Throughout their lifespan, conservative females lived significantly longer and produced significantly more eggs, but the total number of fledglings was not significantly different between strategies. Both strategies coexist over time, persisting within the population under conditions that were common until the late 20th century. If conditions continue to vary, with the occurrence of heatwaves and increases in the frequency of anomalously warm years, bold females may have a selective advantage over conservative females, which might help mitigate the impacts of ocean warming on future populations.

DEPENDENCE OF THE MILK YIELD OF DAIRY COWS ON LINEAR ESTIMATION BY TYPE

Sires breeding value determination was based on classification daughters at the age of first lactation, studies related to the breeding and genetic aspects of line scoring were limited to animals array scoring at the same age. Considering indisputable importance of linear estimation, existing correlative variability between individual descriptive and complex traits growth with dairy productivity and age-related variability in body parts of conformation development, a study was carried out of evaluation influence level of traits linear classification at the age of first lactation on cow milk productivity of subsequent second and third lactations.
 While maintaining a positive correlation in further use of cows, reliability of linear estimation by type was confirmed. Studies conducted on the livestock of Ukrainian Black-and- Red-and-White dairy breeds showed positive correlations between evaluation conformation traits and cow milk yield with variability in their direction, degree and reliability, depending on the recorded lactations. First of all, at the age of first lactation, positive correlation coefficients were determined between conformation traits and milk yield amount of cows, which were a significant confirmation of this breeding event use as one of components in the comprehensive determination of dairy cattle breeding value in the world. Next important element in the aspect of correlative variability conformation traits of linear estimation with productivity was the establishment of sufficiently high correlation coefficients between evaluation four complexes of linear traits by 100-score system with milk yield for first lactation within experimental dairy breeds.
 Positive relationship was, within group traits framework, by estimation of first lactation and milk yield of Ukrainian Black-and- Red-and-White dairy breeds for: dairy type (r=0.502 and 0.447), body (r=0.385 and 0.309), limbs (r=0.129 and 0.154), udder (r=0.404 and 0.383), respectively. Examining the question of whether existing relationship between assessment of group traits of conformation and milk yield amount of cows obtained at the age of first lactation, and between these traits and milk yield for subsequent lactations is preserved, it was found that within compared animals groups of both breeds, separate correlation coefficients received at the age of first lactation, repeated in the second with less force, but at sufficient reliability level. Correlation between indicators of linear estimation group traits of first-calf cows and milk yield for third lactation didn’t repeat level of similar relationships obtained at the age of first and second calving, although a certain pattern of their direction was followed with confirmation reliability of different level. Significant part of descriptive traits of the conformation was associated with milk yield amount for first lactation, as evidenced by reliable correlation coefficients.
 But they decrease with age, and by data of third lactation such relationship was almost absent. Descriptive traits of conformation, correlated with milk yield at the age of first lactation and repeating these relationships with yield at the second and third, belonged to the traits of dairy-type animals were reliable indicators of cow milking. They included: height, chest width, body depth, angularity, rear width, pelvic limb posture, fore udder attachment, rear udder attachment height and central ligament. Thus, reliable level of positive correlation established between estimation of group traits of linear classification at the age of first lactation and milk yield for the next second and third lactation testified about effectiveness of dairy cattle selection, evaluated by conformation type. Level of correlative variability a part of descriptive traits of the conformation with milk yield of first-calf cows will not be repeated in combination indicators of the same estimation with yield at the age of second and third lactations, which was explained by natural unevenness of age-related variability in body type parts development under genotypic and paratypic factors influence.

Long-term annual and spatial variation of polygyny in the white-throated dipper (Cinclus cinclus).

Mating strategies are key components in the fitness of organisms, and notably in birds the occurrence of monogamy versus polygyny has attracted wide interest. We address this by a very comprehensive dataset (2899 breeding events spanning the years 1978–2019) of the white‐throated dipper Cinclus cinclus. Though the mating system of this species has been regarded as generally monogamous, we find that 7% of all breeding events were performed by polygynous males (approximately 15% of all pairs). The fraction of polygyny has been stable over the entire study period irrespective of population size. The assumption that polygyny is most common at low population density was not supported. Surprisingly, there was no difference between polygynous and monogamous males with regard to the quality of the territories they inhabited, ranked according to their overall frequency of use. The most common age group, first‐year breeders, dominated among monogamous males, while among polygynous males second‐year breeders were most common, followed by third and first‐year breeders. The primary females were in general older than females mated to monogamous males, also when controlled for their general frequency in the population. The majority of the two females mated to a polygynous male, bred in the vicinity of each other. The probability for a male to be involved in polygyny more than once, was significantly higher than by chance, suggesting phenotypic quality differences among males.

Exploring Coral Reproduction in Great Depth

Photo 1. Great depths at the Gulf of Aqaba and Eilat, Red Sea, host flourishing reefs with thriving communities of corals, fish, and many other animals. The photos here represent scientific explorations of deep coral reefs (termed “mesophotic reefs”) at depth of 80 m (upper photos) using a remotely operated vehicle (ROV) and at depths of 45–60 m using (lower photos), closed-circuit rebreather dives with different gas mixtures as part of a 5-year study, investigating the reproduction of soft corals along with the depth. Photo credits: TASCMAR project (upper photos), Tom Shlesinger (lower photos). Photo 2. The encrusting soft coral Rhytisma fulvum is a common dweller on many Indo-Pacific reefs, and can be found along a large depth gradient of 0–50 m. In the Red Sea, this species usually displays one of two distinct color morphs: yellow colonies dominate the shallow areas (0–25 m) and purple-white colonies dominate the deeper areas (25–50 m). Photo credit: Tom Shlesinger. Photo 3. Between 2016 and 2020, from June–August, we monitored breeding events of the soft coral Rhytisma fulvum to document the exact timing and intensity of reproductive events across the species' entire depth range (i.e., 0–45 m). In the upper panel, Ronen Liberman (who led this study) observes a yellow morph Rhytisma fulvum colony brimming with 1-day old bright yellow embryos, which are entangled on the coral's surface. In the lower panel, Ronen is collecting samples at a mesophotic reef at Eilat, Red Sea, using decompression technical dives. Photo credits: Jessica Bellworthy (upper photo); Tom Shlesinger (lower photo). Photo 4. Within 6 days following fertilization, the embryos develop into elongated larvae-planulae and are ready to detach from the colony's surface to explore the surrounding reef area for a suitable settlement ground. In the upper panel, elongated yellow-colored planulae that are still caught on the surface of its maternal colony. In the lower panel, the white elongated planulae that were released by the purple Rhytisma fulvum colony begin to crawl on the substrate in search of a suitable location for settlement. Photo credit: Tom Shlesinger. These photographs illustrate the article “Soft coral reproductive phenology along a depth gradient: Can “going deeper” provide a viable refuge?” by Ronen Liberman, Tom Shlesinger, Yossi Loya, and Yehuda Benayahu published in Ecology. https://doi.org/10.1002/ecy.3760

Evidence that catecholaminergic systems mediate dynamic colour change during explosive breeding events in toads.

Many animals communicate by rapidly (within minutes or seconds) changing their body coloration; however, we know little about the physiology of this behaviour. Here we study how catecholaminergic hormones regulate rapid colour change in explosive breeding toads (Duttaphrynus melanostictus), where large groups of males gather and quickly change their colour from brown to bright yellow during reproduction. We find that both epinephrine (EP) and/or norepinephrine (NE) cause the toads' skin to become yellow in minutes, even in the absence of social and environmental cues associated with explosive breeding. We hypothesize that natural selection drives the evolution of rapid colour change by co-opting the functional effects of catecholaminergic action. If so, then hormones involved in ‘fight or flight’ responses may mechanistically facilitate the emergence of dynamic visual signals that mediate communication in a sexual context.

Typical Polygyny and Cooperative Polygyny in Ridgway's Hawk (Buteo ridgwayi)

ABSTRACT Avian mating systems are often monogamous, although polygamy in the form of both polyandry and polygyny are regularly employed by some species and opportunistically practiced by others. Among raptors, multiple species within the genus Buteo have been documented using either polyandrous or polygynous strategies. Here, we describe the first known cases of polygyny in Ridgway's Hawk (B. ridgwayi), a small forest hawk endemic to the island of Hispaniola. This raptor has been studied since the mid-1970s, and intensively during the last 20 yr. Ridgway's Hawks are generally considered to be monogamous; however, we report here observations of polygynous behavior in a recently established, wild population. We consider these polygynous breeding events opportunistic responses that display behavioral flexibility that may serve to benefit the conservation of this critically endangered raptor.

Wearable reproductive trackers: quantifying a key life history event remotely

Advancements in biologging technology allow terabytes of data to be collected that record the location of individuals but also their direction, speed and acceleration. These multi-stream data sets allow researchers to infer movement and behavioural patterns at high spatiotemporal resolutions and in turn quantify fine-scale changes in state along with likely ecological causes and consequences. The scope offered by such data sets is increasing and there is potential to gain unique insights into a suite of ecological and life history phenomena. We use multi-stream data from global positioning system (GPS) and accelerometer (ACC) devices to quantify breeding events remotely in an Arctic breeding goose. From a training set of known breeders we determine the movement and overall dynamic body acceleration patterns indicative of incubation and use these to classify breeding events in individuals with unknown reproductive status. Given that researchers are often constrained by the amount of biologging data they can collect due to device weights, we carry out a sensitivity analysis. Here we explore the relative merits of GPS vs ACC data and how varying the temporal resolution of the data affects the accuracy of classifying incubation for birds. Classifier accuracy deteriorates as the temporal resolution of GPS and ACC are reduced but the reduction in precision (false positive rate) is larger in comparison to recall (false negative rate). Precision fell to 94.5%, whereas recall didn’t fall below 98% over all sampling schedules tested. Our data set could have been reduced by c.95% while maintaining precision and recall > 98%. The GPS-only classifier generally outperformed the ACC-only classifier across all accuracy metrics but both performed worse than the combined GPS and ACC classifier. GPS and ACC data can be used to reconstruct breeding events remotely, allowing unbiased, 24-h monitoring of individuals. Our resampling-based sensitivity analysis of classifier accuracy has important implications with regards to both device design and sampling schedules for study systems, where device size is constrained. It will allow researchers with similar aims to optimize device battery, memory usage and lifespan to maximise the ability to correctly quantify life history events.

The last giants of the Yangtze River: A multidisciplinary picture of what remains of the endemic Chinese sturgeon

The Chinese sturgeon, an important endemism of the Yangtze River, belongs to ‘the most critically endangered group of species’ worldwide, with overfishing and habitat destruction being the main drivers towards extinction. Newly obtained microchemical comparisons between animals and water from different river locations revealed a probable shifting of the spawning ground few kilometers downstream compared to the only previously known site, located under the Gezhouba Dam. This offers a glimmer of hope for an adaptive response to habitat perturbation caused by the recently built Three Gorges dam on the Yangtze River. On the other hand, genetic data provide an estimate of about 20 breeders participating in the only significant breeding event of the past 10 years. This warns of a near species extinction forecast if no in situ and ex situ conservation efforts occur promptly. Given these results we propose a list of priority conservation actions that urgently need to be promoted, supported, and put into practice.

Body Temperature Measurement Reveals the Reproductive Profile of Female Apodemus speciosus under Laboratory and Field Conditions

This study illustrated body temperature (Tb) fluctuation during reproduction and discussed the effectiveness of measuring Tb for predicting the reproductive profile of female Apodemus speciosus both under laboratory and field conditions. Tb fluctuation was monitored for four breeding events in the laboratory and for three in the field. Individual variation in Tb fluctuation during reproduction was larger in the field than in the laboratory, while its temporal pattern was clearer in the field than in the laboratory. Tb fluctuating patterns according to the progress of the reproductive stage were similar between the laboratory and the field. Daily mean Tb increased after the start of pregnancy, decreased during late pregnancy, rapidly increased after parturition, and remained higher through the lactation period. In particular, the following three characteristics should be apparent indices of parturition: increase of daily mean Tb and daily minimum Tb in early pregnancy, decrease of daily max Tb and daily mean Tb in late pregnancy, and increase of daily max Tb at the day of parturition. These results indicate that implanting small-sized loggers enables us to obtain a representative pattern of Tb fluctuation and to predict the reproductive profile of female A. speciosus, both under laboratory and field conditions.

Individual Movements and Habitat Use in Temporary Settlement Areas, Wintering Grounds and Breeding Areas of Saker Falcons Falco cherrug in the Pannonian Basin

Understanding the year-round movement behaviour is fundamental for the effective conservation management of an ecologically important species. In the heavily human-modified landscape of Central Europe, Saker Falcons Falco cherrug have adapted to intensively managed agricultural habitats, often nesting and roosting on electrical pylons. We studied the ranging behaviour and habitat selection of one juvenile and three adult Saker Falcons equipped with GPS/GSM loggers in the Czech Republic and Austria between 2015–2017. Upon release from a rescue centre, the juvenile Saker Falcon used temporary settlement areas (TSAs) with a median size of 231 km2 (minimum convex polygons, MCP 95%). Median of breeding season home ranges for the three adults was 15 km2 over six breeding events. After breeding period, the adults remained close to the nest site, occupying an area with median of 10 km2 until they departed for their autumn migration. Departure dates ranged from 21 September to 9 November. Winter TSA sizes had median of 99 km2. Adults returned to the breeding area between 12 February and 4 March. Annual breeding home ranges overlapped by approximately 84–99% indicating high site fidelity. The most utilised land cover types within winter TSAs included arable land and heterogeneous agricultural areas. Analysis of night-time roosting sites showed a substantial preference for high voltage pylons compared to trees. Our results could benefit conservation planning and species management practices, focusing on both improving the safety of anthropogenic elements and increasing habitat diversity.

Complex associations of weather conditions with reproductive performance in urban population of a common waterbird.

Weather conditions are recognized as one of key determinants of animal reproductive performance; however, the effect of weather on breeding success can be modulated by different features of breeding habitat. Constantly expanding urban areas cause significant changes in land cover and environmental conditions, but whether and how urban landscape mitigates weather impact on animal fitness remains little explored. The aim of this study was to investigate the association between weather parameters and reproductive performance in a reed-nesting waterbird species, theEurasian coot Fulica atra. For this purpose, we performed a long-term monitoring of an urban coot population from central Poland, collecting data for over 400 breeding events. The results indicated that temperature may have contrasting effects on coot reproductive output at different stages of chick-rearing period (positive at early chick-rearing and negative at late chick-rearing). Also, contrary to our expectation, we found a positive relationship between mean daily precipitation in early chick-rearing period and reproductive output in our study population. Our study constitutes one of few examples showing how weather may affect fitness in urban wildlife and provides evidence for high complexity of associations between weather conditions and animal reproductive performance.

Factors Affecting Breeding Success of White Terns (Gygis alba; Aves: Laridae) in Urban Environments of Honolulu, Hawai‘i

The White Tern (Gygis alba) is a common seabird that nests on islands in tropical and subtropical oceans. In the southeastern Hawaiian Islands, White Terns breed only in urban and suburban areas of Honolulu. The Honolulu population has grown from a single pair in 1961 to 2,300 birds in 2016. We measured breeding success of White Terns in Honolulu and examined aspects of their breeding biology and the environment that may affect breeding. We documented 3,855 breeding events in Honolulu from 2016 to 2019. Breeding success was 68.3% and varied less than 3% among years. Breeding occurred in all months, with lowest activity in the summer and a peak in the winter and spring, but the pattern varied among years. White Terns bred in 64 tree species. Breeding success varied among tree species and was related to characteristics of the trees and their attractiveness to non-native predators. The height of breeding events was 9.26 ± 0.05 m and success was related to height, with higher success in events 5–10 m above ground. The diameter of branches on which breeding occurred was 10.2 ± 0.1 cm and success was related to branch diameter, with lower success on branches >20 cm. The high breeding success of White Terns in Honolulu is related to: the small size and isolation of the O‘ahu population, which may result in reduced intra-specific competition for food; protection from predators provided by the urban environment; and trimming of trees by arborists, which unintentionally improves the value of trees as breeding sites for terns.

Sex-specific influence of communal breeding experience on parenting performance and fitness in a burying beetle.

Communal breeding, wherein multiple conspecifics live and reproduce together, may generate short-term benefits in terms of defence and reproduction. However, its carry-over effects remain unclear. We experimentally tested the effects of communal breeding on parental care and reproduction in burying beetles (Nicrophorus vespilloides), which use carcasses as breeding resources and provide parental care to offspring. We subjected individuals to communal or non-communal breeding (i.e. pair breeding) during their first breeding event and to non-communal breeding during their second breeding event. We measured the parental care of individuals and of groups and the reproductive success of groups during both breeding events. In communal groups, large individuals became dominant and largely monopolized the carcass, whereas small individuals (i.e. subordinates) had restricted access to the carcass. At the first breeding event, large males in communal groups spent more time providing care than large males in non-communal groups, whereas such an effect was not observed for large females and small individuals. Reproductive successes were similar in communal and non-communal groups, indicating no short-term benefits of communal breeding in terms of reproduction. Compared with males from non-communal groups, males originating from communal groups produced a larger size of brood during their second breeding event, whereas such an effect was not observed for females. Our results demonstrate the sex-specific effects of communal breeding experience on parenting performance and fitness.

Genetic management on the brink of extinction: sequencing microsatellites does not improve estimates of inbreeding in wild and captive Vancouver Island marmots (Marmota vancouverensis)

Captive breeding is often a last resort management option in the conservation of endangered species which can in turn lead to increased risk of inbreeding depression and loss of genetic diversity. Thus, recording breeding events via studbook for the purpose of estimating relatedness, and facilitating mating pair selection to minimize inbreeding, is common practice. However, as founder relatedness is often unknown, loss of genetic variation and inbreeding cannot be entirely avoided. Molecular genotyping is slowly being adopted in captive breeding programs, however achieving sufficient resolution can be challenging in small, low diversity, populations. Here, we evaluate the success of the Vancouver Island marmot (Marmota vancouverensis; VIM; among the worlds most endangered mammals) captive breeding program in preventing inbreeding and maintaining genetic diversity. We explored the use of high-throughput amplicon sequencing of microsatellite regions to assay greater genetic variation in both captive and wild populations than traditional length-based fragment analysis. Contrary to other studies, this method did not considerably increase diversity estimates, suggesting: (1) that the technique does not universally improve resolution, and (2) VIM have exceedingly low diversity. Studbook estimates of pairwise relatedness and inbreeding in the current population were weakly, but positively, correlated to molecular estimates. Thus, current studbooks are moderately effective at predicting genetic similarity when founder relatedness is known. Finally, we found that captive and wild populations did not differ in allelic frequencies, and conservation efforts to maintain diversity have been successful with no significant decrease in diversity over the last three generations.

Dispersal distance is driven by habitat availability and reproductive success in Northern Great Plains piping plovers

BackgroundDispersal is a critical life history strategy that has important conservation implications, particularly for at-risk species with active recovery efforts and migratory species. Both natal and breeding dispersal are driven by numerous selection pressures, including conspecific competition, individual characteristics, reproductive success, and spatiotemporal variation in habitat. Most studies focus on dispersal probabilities, but the distance traveled can affect survival, fitness, and even metapopulation dynamics.MethodsWe examined sources of variation in dispersal distances with 275 natal dispersal and 1335 interannual breeding events for piping plovers (Charadrius melodus) breeding in the Northern Great Plains between 2014 and 2019.ResultsNatal dispersal was on average longer (mean: 81.0 km, median: 53 km) than adult breeding movements (mean: 23.7 km, median: 1 km). Individuals moved the shortest distances when hatched, previously nested, or settling on river habitats. When more habitat was available on their natal area than in the year prior, hatch-year birds moved shorter distances to their first breeding location. Similarly, adults also moved shorter distances when more habitat was available at the settling site and when in closer proximity to other known nesting areas. Additionally, adult movement distance was shorter when successfully hatching a nest the year prior, retaining a mate, or initiating a current nest earlier.ConclusionHabitat availability appears to be associated with dispersal distance for both hatch-year and adult piping plovers. Conservation efforts that integrate dispersal distances may benefit from maintaining nesting habitat within close proximity to other areas for adults and a network of clustered sites spread out across a larger landscape for natal dispersal.

Inter‐sexual comparison of body biomass, proximate biochemical composition, and fatty acid profiles of new juvenile squat lobsters (Pleuroncodes monodon) in the Southeast Pacific Ocean

AbstractIn the wide distribution range of the red squat lobster Pleuroncodes monodon in the Southeast Pacific Ocean, there is an important nursery area on the southern coast of Chile. The new juvenile individuals from this nursery area are directly recruited into the adult squat lobster population, which is exploited by industrial fisheries. Despite the importance of new P. monodon juveniles for recruitment estimations in fishery management models, their bioenergetic condition and/or nutritional status at the onset of their benthic phase remain unknown, as are the differences in the biochemical composition and energy reserves of the two sexes, which could help explain the cost of the first breeding event in females. Therefore, in new juvenile squat lobsters with the same degree of immaturity, we quantified and compared between the sexes (female vs. male): the size (cephalothorax length, CL), body biomass (dry weight and organic matter), biochemical composition (proteins, glucose, and lipids), and fatty acid profiles (FAs). The results indicate that the CL of new juveniles was similar between the sexes, while the dry weight and organic matter presented significant differences, with higher values in new juvenile females (NJF) than new juvenile males (NJM). Similarly, the NJF had a higher content of proteins, glucose, and lipids than NJM. The FAs also showed significant differences between the sexes; the NJF had a higher content than NJM in all fatty acid classes (i.e., saturated, monounsaturated, and polyunsaturated), with the FAs DHA (C22:6n‐3), EPA (C20:5n‐3), oleic (C18:1n‐9), palmitic (C16:0), and eicosatrienoic (C20:3n‐3) significantly contributing to the differentiation of FA profiles between the sexes. All of the aforementioned differences among the multiple variables of the bioenergetic condition can indicate biochemical adaptations in the storage capacity of energy reserves, particularly among NJF that must support the high energy cost of the first reproductive event (characterized by embryo production and incubation), which occurs during the austral winter, a period predominated by cold‐water temperatures and scarce food availability in the habitat. Overall, our findings have significant implications in fishery management models. In this case, defining the bioenergetic condition of the new juvenile squat lobsters can aid in predicting the density and stability of the adult population, which is exploited by commercial fisheries.