Low Reproductive Rates Research Articles

Supplementary feeding improves breeding performance in Eurasian Eagle Owl (Bubo bubo)

After more than a century of persecution and low reproduction rate, the Eagle Owl is extinct, scarce or still declining in many areas. One possible mitigating action is to supply them artificially with food, but earlier experiments with supplementary feeding of other species have produced varying effects. Supplementary feeding has some caveats and controversies and needs to be tested to avoid counterintuitive management outcomes. Here we present an experimental supplementary feeding trial on a wild population of Eagle Owls on two islands in the middle of Norway. An Eagle Owl population of 27 territories was investigated from 1999 to 2019, and supplementary feeding was provided in three territories over two to seven years. Other important factors for Eagle Owl reproduction that have changed during the 21 years were, in addition to supplementary feeding, included in the GLMM analyses. We found significant earlier egg-laying in territories with supplementary feeding, and a delay in egg-laying in periods with a high corvid population. The probability of producing young increased with supplementary feeding, but was negatively affected by an increased number of pedestrians. This experiment shows that supplementary feeding can enhance breeding performance in Eagle Owls, and that food availability is a limiting factor. Despite that, we would not recommend supplementary feeding as a general mitigating method to help Eagle Owls, because it is time-consuming, the fledglings will have problems surviving if there is not enough food available naturally in the surroundings, and predatory mammals can be attracted to the Eagle Owl territories.

Lead contamination in tissues of large avian scavengers in south-central Europe.

Lead poisoning from spent ammunition is known to affect many avian species. Birds of prey ingest lead when feeding on game shot with lead gunshot or bullets. Raptors with scavenging habits are particularly vulnerable to ingesting lead in areas with intensive hunting and are good indicators of the risk of poisoning from lead ammunition. To assess how much facultative and obligate avian scavengers suffer lead contamination in south-central Europe, between 2005 and 2019 we collected and analysed 595 tissue samples from 252 carcasses of 4 species (golden eagle, bearded vulture, griffon vulture, cinereous vulture). Lead concentrations in organs showed a similar pattern across species with long and small bones revealing the highest median values (5.56 and 6.8mg/kg w.w., respectively), the brain the lowest (0.12), and the liver and kidney the intermediate (0.47 and 0.284). Overall, 111 individuals (44.0%) had lead concentrations above background thresholds in at least one tissue (i.e. >2mg/kg w.w. in soft tissues, >8.33 in bone) and 66 (26.2%) had values indicating clinical poisoning (>6mg/kg w.w. in liver, >4 in kidney, >16.6 in bone). Tissue lead concentrations and incidence of clinical and sub-clinical poisoning were higher in golden eagles and griffon vultures than in bearded and cinereous vultures, likely due to different feeding habits. In all species we found a rapid increase in lead values with age, but differences between age classes were significant only in the golden eagle. Birds with lead fragments in their digestive tract, as detected by X-rays, had higher median lead concentrations, suggesting that hunting ammunition is the main source of lead poisoning. Our results imply that lead impacts the demography of these long-lived species with delayed sexual maturity and low reproduction rate. A rapid transition towards lead-free bullets and gunshot is therefore required across Europe.

Genetic Differentiation and Demographic Trajectory of the Insular Formosan and Orii's Flying Foxes.

Insular flying foxes are keystone species in island ecosystems due to their critical roles in plant pollination and seed dispersal. These species are vulnerable to population decline because of their small populations and low reproductive rates. The Formosan flying fox (Pteropus dasymallus formosus) is one of the 5 subspecies of the Ryukyu flying fox. Pteropus dasymallus formosus has suffered from a severe decline and is currently recognized as a critically endangered population in Taiwan. On the contrary, the Orii’s flying fox (Pteropus dasymallus inopinatus) is a relatively stable population inhabiting Okinawa Island. Here, we applied a genomic approach called double digest restriction-site associated DNA sequencing to study these 2 subspecies for a total of 7 individuals. We detected significant genetic structure between the 2 populations. Despite their contrasting contemporary population sizes, both populations harbor very low degrees of genetic diversity. We further inferred their demographic history based on the joint folded site frequency spectrum and revealed that both P. d. formosus and P. d. inopinatus had maintained small population sizes for a long period of time after their divergence. Recently, these populations experienced distinct trajectories of demographic changes. While P. d. formosus suffered from a drastic ~10-fold population decline not long ago, P. d. inopinatus underwent a ~4.5-fold population expansion. Our results suggest separate conservation management for the 2 populations—population recovery is urgently needed for P. d. formosus while long-term monitoring for adverse genetic effects should be considered for P. d. inopinatus.

Prolonged Alteration of Neonate Traits Following Maternal Exposure to Fishing-Capture Stress During Late Pregnancy in a Chondrichthyan Species

For animals discarded after fishing capture (unwanted bycatch), the effects of fishing-capture stress can extend beyond immediate or delayed death, causing long-term, sub-lethal effects such as injuries and physiological, behavioral, immune, energetic, and reproductive consequences. Given the importance of successful reproduction for population recruitment, investigating reproductive impairment is essential, even more so for animals with low reproductive rates such as chondrichthyans. However, data for these species are lacking, even though the poor conservation status of many chondrichthyan populations and the threats from overexploitation and discard require a better understanding of fishing-capture stress consequences. In this study, we investigated the reproductive consequences of trawling and air exposure stress when experienced by southern fiddler rays (Trygonorrhina dumerilii) during late pregnancy, with a focus on neonatal traits. Compared with neonates from unstressed mothers, neonates born from mothers subjected to capture simulation had significantly lower body mass and yolk sac volume at birth, showed a granulocyte-to-lymphocyte ratio indicative of a stressed condition, reduced growth, altered burying behavior, reduced boldness, and swam for shorter distances after a simulated predator attack. Smaller size and lower growth rate might expose neonates to a higher rate of predation, and similarly, the altered burying and swimming behaviors may reduce their ability to escape from predators. Decreased boldness could impact neonate survival by reducing their ability to compete and obtain food and resources. Further investigations are needed, but these initial results suggest that capture stress suffered by pregnant rays may alter traits and survival of their offspring with consequences for recruitment and population abundance.

On the identity of Labronema baqrii Khan, Jairajpuri and Ahmad, 1989 (Nematoda, Dorylaimida) and analysis of the relationships between the genera Labronema Thorne, 1939 and Talanema Andrássy, 1991

Nematodes are among the most successful and diverse taxa in the animal kingdom, combine endless variation with a deceptively conserved anatomical pattern. Nematodes representing the Order Dorylaimida show K-strategies i.e. having a long life-cycle, low reproduction rate, low colonization ability and are sensitive to disturbance and usually live in a habitat with long durational stability, dominate both in number and species, over other soil-inhabiting nematodes. Andrássy while revising the family Qudsianematidae Jairajpuri, 1965 proposed the genus Talanema Andrássy, 1991 for Labronema Thorne, 1939 species having transverse vulva, subdigitate tail and non-contiguous ventromedian supplements. After almost three decades, the genus is still in need of scientific attention as the addition of new species and transfer of previously described Labronema species make a continuum between the Labronema and Talanema species. In the present work, a pure population of Labronema baqrii Khan, Jairajpuri & Ahmad, 1989 represented by males, females and juveniles isolated from cattle manure from Aligarh, Uttar Pradesh was studied. Herein, we transfer L. baqrii to Talanema and sought to clarify their relationship through molecular and morphological characterization of Talanema baqrii (Khan, Jairajpuri & Ahmad 1989) comb. n. along with the analysis of Labronema species with transverse vulva; conoid, rounded or digitate tail and non-contiguous ventromedian supplements.

The Right-Sized Cow for Emerging and Commercial Beef Farmers in Semi-Arid South Africa: Connecting Biological and Economic Efficiency

The study investigates the right size of cow in terms of both biological and economic efficiency under a typical production system in semi-arid South Africa. Cow size influences biological efficiency of individual animals, which influences herd composition and stock flow on a predetermined resource base. This in turn influences the economic efficiency of the herd. Individual cows were classified as either small, medium, or large and their individual biological efficiency determined. When similar reproduction and growth rates were assumed, large cows were the most biologically efficient, followed by medium and small cows. Income from the herd of small cattle was the lowest, as fewer kilograms of beef were available to sell. Allocated costs for the herd of small cattle were the highest, due to a large number of expenses being charged per head of cattle. Subsequently, when economic efficiency was calculated, the herd of large cattle was more profitable than its smaller counterparts. The herd of large and medium cattle would become less profitable than the herd of small cattle at lower reproduction rates, and these reproduction rates were calculated. Smaller cattle have a faster maturity rate than larger cattle. A faster maturity rate provides the opportunity for early breeding. The effect of limiting feed intake of small, medium, and large cattle was compared and yielded varying results. The study concluded that cattle size influences biological efficiency, biological efficiency influences economic efficiency however there are many more variables that influence biological and economic efficiency other than size, such as reproduction rates.

High elevation bird communities in the Swiss Alps exhibit reduced fecundity and lifespan independently of phylogenetic effects

The merging of community ecology and phylogenetic biology allows us to link broader evolutionary processes to local ecological processes, thereby increasing our understanding of community assembly. A recurrent way to test how species assemblages respond to different abiotic conditions and evaluate the role of evolutionary constraints in community assembly is through using environmental gradients as natural treatments. Here, we combine phylogenetic and trait-based methods to evaluate how the phylogenetic diversity and composition of bird assemblages and their community-weighted traits vary along an elevational gradient in the Swiss Alps. For this purpose, we used four life-history traits considered to be key indicators of individual species response to environmental changes: clutch size, number of breeding attempts, dispersal capacity and lifespan. Controlling for phylogeny, we determined whether environmental filters (elevation, habitat type) act on these traits independently of the level of relatedness among species. We found that phylogenetic dispersion decreases with elevation, but the signature of phylogenetic clustering was weak. Phylogenetic fuzzy weighting showed that the distribution of bird species across plots was related to the two environmental gradients; nonetheless, such influence was not determined by the phylogenetic relationships in either case. That is, there are no specific clades associated with particular elevation or habitat types. We also found that high elevation communities around the treeline were composed of species with lower reproductive rates, reduced lifespan, and lower dispersal capacity, which would make them less resilient to environmental change. Although traits showed moderate phylogenetic signal, only the lifespan was phylogenetically structured. In the remaining cases, the trait-environment association was not mediated by the phylogenetic relationships among taxa. Our study indicates that evolutionary constraints do not represent a significant driver of community assembly in Alpine bird communities and support the notion that phylogeny may often not be a good proxy for traits subject to environmental filtering.

Long-term population trends of Rhinolophus hipposideros and Myotis myotis in Poland

Bats are particularly susceptible to environmental changes because of their low reproductive rate, longevity, and high metabolic rates, which lead to relatively high food requirements. Thus, bat populations take a relatively long time to recover from increased mortality rates, and monitoring schemes should cover long time periods. In this work, we analyzed the population trajectories of two bat species, Rhinolophus hipposideros and Myotis myotis, the most numerous in five caves in southern Poland, which are known as important bat hibernacula on a continental scale. Data were collected by regular counts in 1985–2020, depending on the particular cave; in addition, previous data on the number of hibernating bats in these caves, available since 1951, were taken from existing publications. We analyzed time-series data using average locality indices and TRIM (TRends and Indices for Monitoring data) methods, and both produced similar results. Generally, the populations of the two studied bat species showed recent increasing trends, especially visible as an effect of recovery after years of decline. The situation recorded in southern Poland is very similar to that described in other places in Europe, where recoveries of bat populations have also been observed in the last decades. Although it is difficult to present results from formal analyses, because of the lack of good data, at least some factors—less exposure to contaminants (pesticides, heavy metals), improving food availability due to climate change, and a lower predation rate (including human pressure), both in the breeding season and during wintering—positively affected both species.

Eco-Biology, Threats and Conservation Problems of Indian Vulture in Southern Rajasthan, India

Vultures are very efficient and powerful natural scavengers in ecosystem, they usually feed upon carcass of domestic and wild animals. India is a home of nine specie of vultures they are very sensitive towards changes in habitat and climatic conditions. Vultures required large territories, selective diet and unique habitats for its survival. Vulture populations dramatically and rapidly declined from last 30 years due to acute and chronic renal failure and avian gout disease. Major reasons of vulture declined due to extensive use of veterinary drugs like diclofenac, ketofenac, fluxin, carprofen and nimesulide for treatment of domestic animals in various diseases. Other factor also responsible for vulture’s population declined due to habitat destruction, lack of roosting and nesting habitat, mortality due to electrocution and collision with wind turbine, road killing and low reproductive success rate responsible for its survival and population decline. Male and female of Indian vultures are morphologically similar in shape and size. Vulture’s having slow breeding rate and usually laid single egg per year or in every breeding season. Vultures collectively feed upon carrion and sometime inter & intra specific competition observed at feeding and roosting times. Indian vulture usually construct nest upon rock cliffs and old historical monuments area where cliffs are absent they generally construct nest on large and old trees. GPS tagging and satellite monitoring helpful for finding daily, seasonal, local and global migratory route of species.

Reproductive risks in 35-year-old adults born very preterm and/or with very low birth weight: an observational study

Evidence suggests that increased survival over the last decades of very preterm (VPT; gestational age < 32 weeks)– and very low birth weight (VLBW; birth weight < 1500 g)–born infants is not matched by improved outcomes. The objective of our study was to evaluate the reproductive rate, fertility, and pregnancy complications in 35-year-old VPT/VLBW subjects. All Dutch VPT/VLBW infants born alive in 1983 and surviving until age 35 (n = 955) were eligible for a POPS-35 study. A total of 370 (39%) subjects completed a survey on reproductive rate, fertility problems, pregnancy complications, and perinatal outcomes of their offspring. We tested differences in these parameters between the VPT/VLBW subjects and their peers from Dutch national registries. POPS-35 participants had less children than their peers in the CBS registry. They reported more problems in conception and pregnancy complications, including a three times increased risk of hypertension during pregnancy.Conclusion: Reproduction is more problematic in 35-year olds born VPT/VLBW than in the general population, possibly mediated by an increased risk for hypertension, but their offspring have no elevated risk for preterm birth.What is known:At age 28, the Dutch national POPS cohort, born very preterm or with a very low birth in 1983, had lower reproductive rates than the general Dutch population (female 23% versus 32% and male 7% versus 22%).What is new:At age 35, the Dutch POPS cohort still had fewer children than the general Dutch population (female 56% versus 74% and male 40% versus 56%). Females in the POPS cohort had a higher risk of fertility problems and pregnancy complications than their peers in the Dutch national registries, but their offspring had no elevated risk for preterm birth.

Inconclusive evidence of sexual reproduction of invasive Halophila stipulacea: a new field guide to encourage investigation of flower and fruit production throughout its invasive range

Abstract The dioecious seagrass species Halophila stipulacea reproduces mainly through fast clonal growth, underlying its invasive behavior. Here, we provide morphological evidence to show that the first findings of fruits in the Caribbean were misidentified. Consequently, H. stipulacea reproduction is likely still only asexual in the Caribbean. Therefore, we introduce an identification key of H. stipulacea reproductive structures to encourage careful identification and quantification throughout its invasive range. Until large-scale seed production in invaded habitats is reported, the apparent low rate of sexual reproduction needs to be considered in current studies investigating the invasion capacity of this species.

Evaluation of Biological Reference Points for Conservation and Management of the Bigeye Thresher Shark, Alopias superciliosus, in the Northwest Pacific

Full stock assessment of sharks is usually hindered by a lack of long time-series catch and effort data. In these circumstances, demographic and per-recruit analyses may provide alternate approaches to describe population status because these methods can be applied to estimate biological reference points (BRPs) for shark stocks. However, the appropriate level of BRPs for sharks is difficult to determine, given the expected low reproductive rates. To determine which BRPs are most appropriate for the CITES-listed species—bigeye thresher shark, Alopias superciliosus, a stochastic demographic model with Monte Carlo simulations and per-recruit models were used to estimate BRPs in this study. The results indicated that conventional fishing mortality-based BRPs (FBRPs) derived from per-recruit models may result in a clear population decline. Our analyses also demonstrated that the bigeye thresher population in the Northwest Pacific will stabilize only if demographic-based FBRP is implemented. The FBRP estimated based on the stochastic demographic model was 0.079–0.139 y−1, which was equivalent to SPR = 50–70%. The findings strongly suggested that more conservative threshold FBRPs should be implemented to ensure sustainable utilization of the bigeye thresher stock. The present study provides new and strategically important information on the population dynamics of the bigeye thresher in the Northwest Pacific, which can be used to help fishery managers to adopt more efficient management measures for this stock. It is also suggested that this approach can be applied to other shark species with limited catch and effort data.

Shift in proximate causes of mortality for six large migratory raptors over a century

Delayed maturity and low reproductive rate make raptors naturally sensitive to high mortality rates, yet a wide variety of human-related threats negatively affect their population dynamics and persistence over time. We modelled the variability in the proximate causes of mortality associated with six species of large migratory raptors characterized by different ecological traits. We tested the hypothesis that species-specific mortality signals occur owing to differential exposure to threats in space and time. We relied on an unprecedently large dataset of ring (band) recovery (31,269 records) over a period of >100 years. Our findings suggested that mortality of these birds has declined dramatically since the late 1970s. We found species-specific seasonal patterns of mortality, with higher mortality rates during early life-stages. For Black Kite, Common Buzzard, and Osprey, mortality increased with distance travelled and decreased with distance from migratory bottlenecks. Human-related mortality was higher than natural mortality (47% vs 5.6%), but after 1979 indirect anthropogenic factors increased, while direct ones decreased. Raptors showed differential specific exposure to mortality causes (direct human: Honey Buzzard, Marsh Harrier; indirect human: Common Buzzard, Black Kite; direct and indirect human: Osprey; natural: Montagu's Harrier). Conservation efforts and international laws have helped lower mortality caused directly by humans, but new emerging human-related threats are impacting migratory raptors and call for advanced conservation efforts. In a fast-changing world, anticipating future threats is key to stemming losses and boosting future preservation.

From Safety Net to Point of No Return—Are Small-Scale Inland Fisheries Reaching Their Limits?

Small-scale inland fisheries (SSIF) are a livelihood opportunity for millions of people in developing countries. Understanding the economic, ecological, political and social impacts fishers are coping with can clarify weaknesses and challenges in the fishery management. Using the SSIF at Lake Alaotra, Madagascar, as an example, we analyzed the development and fishers’ perception of, and adaptation strategies to, change. We surveyed fish catches to assess the state of fish stocks and conducted interviews to understand fishers’ livelihood, problems, behavior and attitudes. Our results show that the fishery sector of Lake Alaotra has grown dramatically although fish catches have fallen sharply. Changes in species composition and low reproduction rates reflect the fishing pressure. A point of no return seems near, as decreasing agricultural yields force farmers to enter the fishery sector as a form of livelihood diversification. Lake Alaotra reflects an alarming trend which can already be seen in many regions of the world and may affect a growing number in the near future. The Alaotran fisheries demonstrate that SSIF’s ability to provide livelihood alternatives under conditions of insecurity will become increasingly important. It further highlights that the identification of ongoing livelihood dynamics in order to disclose possible poverty trap mechanisms and to understand fisheries’ current function is essential for sustainable management.

Harp Seals: Monitors of Change in Differing Ecosystems

Harp seals are the most abundant marine mammal in the north Atlantic. As an ice obligatory predator, they reflect changes in their environment, particularly during a period of climatic change. As the focus of a commercial hunt, a large historic data set exists that can be used to quantify changes. There are three populations of harp seals: White Sea/Barents Sea, Greenland Sea and Northwest Atlantic. Although important historically, recent catches have been low in the two northeast Atlantic populations and do not appear to be influencing trends in either population. Massive mortalities of White Sea/Barents Sea seals occurred during the mid 1980s due to collapses in their major prey. Between 2004 and 2006, pup production declined by 2/3 and has remained low. Body condition declined during the same period, suggesting that ecosystem changes may have resulted in reduced reproductive rates, possibly due to competition with Atlantic cod. The most recent estimate pf pup production in the Greenland Sea also suggests a possible decline during a period of reduced hunting although the trend in this population is unclear. Pupping concentrations are closer to the Greenland coast due to the reduction in ice in the traditional area and increased drift may result in young being displaced from their traditional feeding grounds leading to increased mortality. Reduced ice extent and thickness has resulted in major mortality of young in the Northwest Atlantic population in some years. After a period of increase, the population remained relatively stable between 1996 and 2013 due to increased hunting, multiple years with increased ice-related mortality of young seals, and lower reproductive rates. With a reduction in harvest and improved survival of young, the population appears to be increasing although extremely large interannual variations in body condition and fecundity have been observed which were found to be influenced by variations in capelin biomass and ice conditions. Each of these populations has been impacted differently by changes in their ecosystems and hunting practices. By identifying the factors influencing these three populations, we can gain a better understanding of how species may respond to changes that are occurring in their ecosystems.

Invasion and fixation of microbial dormancy traits under competitive pressure

Microbial dormancy is an evolutionary trait that has emerged independently at various positions across the tree of life. It describes the ability of a microorganism to switch to a metabolically inactive state that can withstand unfavourable conditions. However, maintaining such a trait requires additional resources that could otherwise be used to increase e.g. reproductive rates. In this paper, we aim for gaining a basic understanding under which conditions maintaining a seed bank of dormant individuals provides a “fitness advantage” when facing resource limitations and competition for resources among individuals (in an otherwise stable environment). In particular, we wish to understand when an individual with a “dormancy trait” can invade a resident population lacking this trait despite having a lower reproduction rate than the residents. To this end, we follow a stochastic individual-based approach employing birth-and-death processes, where dormancy is triggered by competitive pressure for resources. In the large-population limit, we identify a necessary and sufficient condition under which a complete invasion of mutants has a positive probability. Further, we explicitly determine the limiting probability of invasion and the asymptotic time to fixation of mutants in the case of a successful invasion. In the proofs, we observe the three classical phases of invasion dynamics in the guise of Coron et al. (2017, 2019).

Genetic variation among full-sib families and the effect of non-genetic factors on growth traits at harvest in Clarias magur (Hamilton, 1822)

Magur (Clarias magur) is an Indian catfish species with a good potential for aquaculture. The expansion of magur aquaculture is hindered because of low reproductive and survival rates. Furthermore, males need to be sacrificed to collect milt for artificial fertilization. At present, magur seed production mainly depends on the wild-caught juveniles and to a smaller extent, from broodfish whose genetic potential is unknown. The availability of high-quality seeds in a sustainable way can be ensured through the selective breeding program for magur. The knowledge of factors influencing growth traits and their genetic parameters is a pre-requisite for implementing a genetic selection program. The present study aimed to quantify the performance of C.magur reared in a two-year class and estimate their heritabilities at stocking and harvest and also to estimate the genetic and phenotypic correlations among them. The growth traits such as Body Weight (BW), Total Length (TL), Body Depth (BD), Head Width (HW), and Average Daily Gain (ADG) were recorded from 1413 animals belonging to 78 fullsib families produced by adopting single pair mating design, after one year of pond culture (traits at harvest). Genetic parameters were also estimated for body weight (BW0) and total length (TL0) measured from 2328 fish from 78 fullsib families at the time of stocking. Magur attained an average BW of 135 g and 24.5 cm TL after one year culture period. The heritabilities of BW, TL, and ADG were 0.44 ± 0.07, 0.32 ± 0.06, and 0.42 ± 0.07, respectively and may be biased upwardly due to the single pair mating design. Genetic correlations between harvest traits were all positive and varied in magnitude between traits (0.74 to 0.99). The results obtained from the current study indicate the presence of genetic variation in magur population for growth traits and selection based on genetic merit can produce improvement in these traits.

Response of female black bears to a high‐density road network and identification of long‐term road mitigation sites

AbstractRoads can result in negative effects on wildlife including habitat loss, behavioral avoidance, reduced survival, reproduction and gene flow. These road effects are especially pronounced for large mammals given their large home‐range requirements and low reproductive rates. To counteract these negative effects, road mitigation measures, such as underpasses and overpasses, are promoted; however, future landscape changes are rarely considered when selecting mitigation locations. We used GPS telemetry data on female American black bears Ursus americanus to examine their response to roads in Massachusetts, US. We compared bear road crossing frequency with a null crossing model derived from a correlated random walk, estimated road crossing movement speeds, and fit a road‐crossing resource selection function. We found that, though black bears crossed roads less than expected based on the null model, 10% of their observed steps, on average, crossed roads. We also found bears crossed roads at higher movement speeds than during other home‐range behaviors, and that bears preferred to cross smaller, less trafficked roads in areas with lower speed limits, less human development and more forest. We used the resource selection model to identify road segments for potential mitigation efforts and then used future human development projections to forecast future changes in these segments. We found a decrease of 15% in the length of suitable mitigation segments from 2019 to 2050. Given the sizeable investment in wildlife crossing structures and their longevity on the landscape, we recommend incorporating future projections into crossing site selection to ensure the long‐term viability of road mitigation efforts.

Genetic Evaluation of Population Structure in Tautog

AbstractTautog Tautoga onitis supports both recreational and growing commercial fisheries from Virginia to Massachusetts. Tautogs, which aggregate around structured habitats (wrecks, rocks, bridge pilings, etc.), are slow to mature and have a low reproductive rate relative to other teleosts. Slow growth and easy catchability result in Tautogs being extremely vulnerable to overexploitation, and their populations are slow to rebuild. At present, Tautogs are managed by the Atlantic States Marine Fisheries Commission as four separate regions: Massachusetts–Rhode Island, Long Island Sound, New Jersey–New York Bight, and Delaware–Maryland–Virginia, despite a lack of genetic information to support this management scenario. The objective of the current study was to investigate the genetic connectivity of Tautogs throughout their management zone and provide stock structure information in support of fisheries management. We developed and used 18 variable microsatellite loci to evaluate the genetic structure of 789 Tautogs sampled across their effective U.S. East Coast range from Massachusetts to North Carolina. We also amplified and sequenced a 1,267 base pair portion of the mitochondrial DNA control region from Tautogs sampled from Massachusetts and Virginia. Comparison of pairwise FST values among samples collected from locations south of Cape Cod, Massachusetts, were low and nonsignificant, suggesting that gene flow is sufficient to prevent the accumulation of genetic differences. The collection from Cape Cod Bay, Massachusetts, was genetically distinct from all other samples (FST = 0.021 to 0.046), indicating that Cape Cod is a significant barrier to dispersal for Tautogs and suggesting that Tautogs north and south of Cape Cod should be managed as separate stocks.

Population size and density in two European pond turtle populations of central Italy

Abstract Two populations of the European pond turtle were studied employing capture, marking and recapture (CMR) techniques to determine population density and abundance in natural and protected areas within the Regional Natural park Migliarino San Rossore Massaciuccoli in north western Tuscany, Italy. The results indicated strong sexual size dimorphism in both populations, with males smaller than females. In one area Emys orbicularis was in general smaller in size with a very low reproductive rate (three out of 25 adult females were gravid), which contrasted with a second population where 20 out of 42 females were gravid. Population estimates indicated 79 turtles were present in the first area (0.34 ha) and 61 turtles in the second area (0.58 ha), giving an overall density estimate of 183.6 turtles/ha and 146.7 turtles/ha respectively. Whilst our results are similar to those found in other areas of Europe, they diverge from other regions, suggesting that sampling and monitoring techniques should be standardized to obtain comparable data that will enable conservation and protection measures to be recommended.