Low Reproductive Rates Research Articles

Oviduct morphology and estrogen receptors ERα and ERβ expression in captive Chinchilla lanigera (Hystricomorpha: Chinchillidae)

Chinchilla lanigera is a hystricomorph rodent from South America whose reproductive biology presents particular characteristics that distinguishes it from other Rodentia species, such as low reproductive rate, seasonal breeding pattern, and long estrous cycle. Nevertheless, reproductive features in female chinchillas are still poorly investigated, with a scarce knowledge concerning the estrous cycle and the histology of reproductive organs. In this study, we investigate the morphology, histomorphometry, secretory activity, and immunolocalization of estrogen receptors ERα and ERβ in oviducts of nulliparous chinchillas, euthanized at fall season in Brazil. Follicular phase of estrous cycle of all studied animals was characterized by ovary and uterine morphology inspection, as well as vaginal cytology. Similar to other mammals, the oviduct wall of infundibulum, ampulla and isthmus was composed of mucosa, muscle, and serosa layers. Morphometric data of oviduct layers were used for identifying each oviduct segment. In the follicular phase, the oviduct was characterized by intense secretory activity, mainly in the ampulla, and expression of ERα and ERβ throughout the oviduct epithelium. Both ERα and ERβ were also detected in the connective tissue and smooth muscle cells. Our findings point out to the important role of estrogen in this female organ. Similar wide distribution of both ER proteins has been described for human Fallopian tube. Taken together, our data add to the understanding of the reproductive biology of female chinchillas, and may assist in the intensive breeding of this species and any eventual endeavor for conservation of chinchillas in the wild.

Bat-mouse bone marrow chimera: a novel animal model for dissecting the uniqueness of the bat immune system

Bats are an important animal model with long lifespans, low incidences of tumorigenesis and an ability to asymptomatically harbour pathogens. Currently, in vivo studies of bats are hampered due to their low reproduction rates. To overcome this, we transplanted bat cells from bone marrow (BM) and spleen into an immunodeficient mouse strain NOD-scid IL-2R−/− (NSG), and have successfully established stable, long-term reconstitution of bat immune cells in mice (bat-mice). Immune functionality of our bat-mouse model was demonstrated through generation of antigen-specific antibody response by bat cells following immunization. Post-engraftment of total bat BM cells and splenocytes, bat immune cells survived, expanded and repopulated the mouse without any observable clinical abnormalities. Utilizing bat’s remarkable immunological functions, this novel model has a potential to be transformed into a powerful platform for basic and translational research.

An experimental test of alternative population augmentation scenarios.

Human land use is fragmenting habitats worldwide and inhibiting dispersal among previously connected populations of organisms, often leading to inbreeding depression and reduced evolutionary potential in the face of rapid environmental change. To combat this augmentation of isolated populations with immigrants is sometimes used to facilitate demographic and genetic rescue. Augmentation with immigrants that are genetically and adaptively similar to the target population effectively increases population fitness, but if immigrants are very genetically or adaptively divergent, augmentation can lead to outbreeding depression. Despite well-cited guidelines for the best practice selection of immigrant sources, often only highly divergent populations remain, and experimental tests of these riskier augmentation scenarios are essentially nonexistent. We conducted a mesocosm experiment with Trinidadian guppies (Poecilia reticulata) to test the multigenerational demographic and genetic effects of augmenting 2 target populations with 3 types of divergent immigrants. We found no evidence of demographic rescue, but we did observe genetic rescue in one population. Divergent immigrant treatments tended to maintain greater genetic diversity, abundance, and hybrid fitness than controls that received immigrants from the source used to seed the mesocosms. In the second population, divergent immigrants had a slightly negative effect in one treatment, and the benefits of augmentation were less apparent overall, likely because this population started with higher genetic diversity and a lower reproductive rate that limited genetic admixture. Our results add to a growing consensus that gene flow can increase population fitness even when immigrants are more highly divergent and may help reduce uncertainty about the use of augmentation in conservation.

Inheritance and fitness costs of Spodoptera frugiperda (Lepidoptera: Noctuidae) resistance to spinosad in Brazil.

Spodoptera frugiperda is a pest of economically important crops in South America. In Brazil, this species is considered the most destructive pest of maize. Use of spinosyn insecticides in insect resistance management (IRM) has been one strategy to control this pest. In this study, we selected a strain of S. frugiperda resistant to spinosad and evaluated the inheritance and fitness costs of the resistance. Estimated LC50 (concentration required to kill 50% of larvae) values were 0.011 and 9.80 µg cm-2 for the spinosad-susceptible (Sus) and -resistant (Spin-res) strains, respectively. This represents an 890-fold resistance ratio. LC50 values for reciprocal crosses were 0.18 and 0.14 µg cm-2 , indicating that resistance to spinosad is an autosomal incompletely recessive trait. Backcrosses of the F1 progeny from reciprocal crosses with the parental Spin-res strain showed a polygenic effect. The estimated minimum number of independent segregations was ∼ 2.45, indicating that resistance to spinosad is associated with multiple genes. In greenhouse assays, third-instar larvae from the Spin-res strain showed >92% survival on spinosad-treated maize. By contrast Sus and reciprocal crosses exhibited 0% and <5% survival, respectively, indicating that resistance is recessive. Life history studies to investigate the fitness cost of resistance revealed a 41% reduction in the rate of survival to adulthood and a 49% lower reproductive rate in the Spin-res strain compared with the Sus strain. The autosomal, incompletely recessive and polygenic resistance to spinosad in S. frugiperda and the fitness costs associated with this resistance can be exploited in IRM strategies to preserve the lifetime of spinosad for control of S. frugiperda in Brazil. © 2017 Society of Chemical Industry.

On the possible role of ticks in the eco-epidemiology of Coxiella burnetii in a Mediterranean ecosystem

Ruminant livestock is the main reservoir of Coxiella burnetii (Cb), but little is known about the role of wildlife and ticks in its epidemiology. The Iberian ibex (Capra pyrenaica, Schinz 1838) population of “Ports de Tortosa i Beseit” (NE Spain) suffers intense tick infestations and low reproduction rates. This study aims to (1) assess the relationship between infection in ibexes (detection of serum antibodies and/or of Cb DNA in tissues) and Cb DNA presence in ticks hosted by the same ibexes; and (2) identify Cb associated risk factors. Between 2011 and 2015, serum (n = 130), spleen (n = 72), lymph node (n = 89) and tick (n = 669) samples from 134 hunter-harvested ibexes were collected. Antibody detection was performed by ELISA and Cb DNA presence was assessed by PCR. Potential risk factors were assessed with regression tree models. Although 30% of the ibexes (39/130; 95%CI, [10%–29.8%]) had antibodies, Cb DNA was detected in only 9.8% of the ibexes (11/112; 95%CI [7.6%–27.25%]). The prevalence of Cb-carrier ticks averaged 10% and exceeded 20% for the genus Haemaphysalis. However, lacking correlation between infection in ibexes and their ticks does not support tick-to-ibex transmission or vice versa. Tree modelling points to host, population and environmental factors as drivers of Cb infection in ticks and suggests connections with the domestic cycle. The percentage of Cb-carrier ticks detected is noteworthy. Along with heavy tick infestations, it suggests vector potential for these tick species, especially for the genera Rhipicephalus and Haemaphysalis. Since vector competence has not been assessed in these tick species, a classic vector role cannot be proposed nor discarded, but promoter factors of vector capacity occur. In addition, the risk of tick-borne infection through tick excreta should not be neglected. While the airborne route is the preeminent route for Cb infection, ticks' contribution to Cb epidemiology deserves further attention.

Micropropagation of Yucca Species.

Yuccas are plants adapted to arid and semiarid regions and have been used as source of food and raw materials and for ornamental purposes. Lately, the interest in this genus has grown due to the presence of potential useful compounds such as saponins and polyphenolics. However, they present very low reproductive rates and virtually all the plants used are wild individuals; as consequence, their natural populations have been depleted. We present an efficient method to establish in vitro cultures of Yucca species starting with seeds and then obtaining shoots from the seedling meristems using cytokinins and auxins. These shoots can be rooted and transferred to soil or can be used as explants for another multiplication cycle. Hence, it is necessary to acquire seeds just once to establish a large-scale micropropagation protocol.

Reproducción y mortalidad de razas bovinas en clima subtropical de Argentina

Tropical environmental climate causes low reproductive rates in cattle, so the objective of the present study was to evaluate the possible effects of the climate on the reduction of the rates of bovine reproduction. The work was carried out in the Experimental Agriculture Station (EAS) in Corrientes, Argentina, where, 3,082 bovine herd records data were analyzed from 1991 to 2009, three breeds, Hereford (HR), Braford (BF) and Brahman (BH). It was evaluated the percentage of losses from the diagnosis of gestation until the delivery (DP) and from the delivery until the weaning to the 205 d (PD). Data were analyzed by analysis of variance in a completely randomized design and with an analysis of correlation. The greater losses (P 0.05) between DP and PD. There was a correlation between the humidity and the radiation with the cows that were not in gestation (HR and BF), the cows BH not presented any relation. Key words: Mortality, bovines, efficiency.

Warfare and wildlife declines in Africa's protected areas.

Large-mammal populations are ecological linchpins, and their worldwide decline and extinction disrupts many ecosystem functions and services. Reversal of this trend will require an understanding of the determinants of population decline, to enable more accurate predictions of when and where collapses will occur and to guide the development of effective conservation and restoration policies. Many correlates of large-mammal declines are known, including low reproductive rates, overhunting, and habitat destruction. However, persistent uncertainty about the effects of one widespread factor-armed conflict-complicates conservation-planning and priority-setting efforts. Case studies have revealed that conflict can have either positive or negative local impacts on wildlife, but the direction and magnitude of its net effect over large spatiotemporal scales have not previously been quantified. Here we show that conflict frequency predicts the occurrence and severity of population declines among wild large herbivores in African protected areas from 1946 to 2010. Conflict was extensive during this period, occurring in 71% of protected areas, and conflict frequency was the single most important predictor of wildlife population trends among the variables that we analysed. Population trajectories were stable in peacetime, fell significantly below replacement with only slight increases in conflict frequency (one conflict-year per two-to-five decades), and were almost invariably negative in high-conflict sites, both in the full 65-year dataset and in an analysis restricted to recent decades (1989-2010). Yet total population collapse was infrequent, indicating that war-torn faunas can often recover. Human population density was also correlated (positively) with wildlife population trajectories in recent years; however, we found no significant effect, in either timespan, of species body mass, protected-area size, conflict intensity (human fatalities), drought frequency, presence of extractable mineral resources, or various metrics of development and governance. Our results suggest that sustained conservation activity in conflict zones-and rapid interventions following ceasefires-may help to save many at-risk populations and species.

A review of urban impacts on avian life-history evolution: Does city living lead to slower pace of life?

The concept of a pace-of-life syndrome describes inter- and intraspecific variation in several life-history traits along a slow-to-fast pace-of-life continuum, with long lifespans, low reproductive and metabolic rates, and elevated somatic defences at the slow end of the continuum and the opposite traits at the fast end. Pace-of-life can vary in relation to local environmental conditions (e.g. latitude, altitude), and here we propose that this variation may also occur along an anthropogenically modified environmental gradient. Based on a body of literature supporting the idea that city birds have longer lifespans, we predict that urban birds have a slower pace-of-life compared to rural birds and thus invest more in self maintenance and less in annual reproduction. Our statistical meta-analysis of two key traits related to pace-of-life, survival and breeding investment (clutch size), indicated that urban birds generally have higher survival, but smaller clutch sizes. The latter finding (smaller clutches in urban habitats) seemed to be mainly a characteristic of smaller passerines. We also reviewed urbanization studies on other traits that can be associated with pace-of-life and are related to either reproductive investment or self-maintenance. Though sample sizes were generally too small to conduct formal meta-analyses, published literature suggests that urban birds tend to produce lower-quality sexual signals and invest more in offspring care. The latter finding is in agreement with the adult survival hypothesis, proposing that higher adult survival prospects favour investment in fewer offspring per year. According to our hypothesis, differences in age structure should arise between urban and rural populations, providing a novel alternative explanation for physiological differences and earlier breeding. We encourage more research investigating how telomere dynamics, immune defences, antioxidants and oxidative damage in different tissues vary along the urbanization gradient, and suggest that applying pace-of-life framework to studies of variation in physiological traits along the urbanization gradient might be the next direction to improve our understanding of urbanization as an evolutionary process.

Monitoring health and reproductive status of olms (Proteus anguinus) by ultrasound.

The olm (Proteus anguinus) is a troglomorphic, neotenous amphibian with extraordinary life expectancy and unique adaptations that deserve further investigation. A low reproductive rate and habitat decline render it threatened by extinction. Establishing captive populations for maintenance and artificial breeding may one day become crucial to the species. Longitudinal, in-vivo assessment of inner organs is invaluable to our understanding of reproductive physiology, health, and behavior. Using ultrasound, we measured heart rate and assessed health and reproductive status of 13 captive olms at Zagreb Zoo. Heart rate averaged 42.9 ± 4.6 bpm (32–55 bpm), as determined via pulsed-wave Doppler at 4–12 MHz. By using frequencies of up to 70 MHz (ultrasound biomicroscopy), inner organs were visualized in detail. Assessment of the gastrointestinal tract provided insights into feeding status and digestive processes. Several subclinical pathologies were detected, including biliary sludge, subcutaneous edema, ascites, and skin lesions. Detection of skin lesions by ultrasound was more sensitive than visual adspection. Olms with ultrasonographically detected skin lesions tested positive for Saprolegnia and were treated. Three of the four affected individuals survived and subsequently tested negative for Saprolegnia. Sex was reliably determined; only one individual proved male. The reason for this extreme female-biased sex-ratio remains unknown. However, as most of the individuals were flushed from the caves by strong currents in spring, the sample may not be representative of natural populations. In female olms, different stages of ovarian follicular development were observed with diameters ranging between 0.1 and 1.1 mm. Results were confirmed by comparing ultrasound, necropsy, and histological findings of one dead specimen. In summary, ultrasound proved a valuable tool to support conservation and captive breeding programs by allowing non-invasive assessment of physiological parameters, clinical condition, and reproductive status in olms.

In Vitro Propagation of Agave americana by Indirect Organogenesis

Factors such as slow growth, low rates of sexual and asexual reproduction, and viability of seeds among others limit the massive propagation of Agave americana L. by conventional methods. In this study, callus induction and shoot proliferation was determined in A. americana using Murashige and Skoog (MS) medium supplemented with dicholorophenoxyacetic acid (2,4-D) and 6-benzyl adenine (BA). Meristematic tissue was used as the explants, and were placed on MS medium supplemented with 30.0 g·L−1 sucrose with 0.11, 0.18, or 0.45 μm 2,4-D and 11.0, 22.0, 38.2, 44.0, 58.7, or 73.3 μm BA. Treatments were implemented according to factorial experimental design 3 × 6. After 1 month, the number of explants with callus was determined, whereas the numbers of shoots per explant were monitored after 4, 16, 20, and 36 weeks. The maximum percent of explants with callus was obtained with 0.11 μm 2,4-D and 58.7 and 73.3 μm BA, whereas the maximum numbers of shoots per explant (71) were obtained with 0.11 μm 2,4-D and 73.3 μm BA. The effect of different concentrations of indolebutyric acid (IBA) in the rooting of shoots was evaluated. There were no significant effects of IBA on the number of roots, root length, and axillary roots. Plantlets were acclimatized in the glasshouse and they did not show any phenotypic alteration. This is a highly efficient protocol for the in vitro propagation of A. americana via indirect organogenesis.

Roadside Abundance of Anurans within a Community Correlates with Reproductive Investment

Roads and their associated effects (road-kill, pollution, etc.) have a largely negative impact on animals, especially amphibians, but not all species are affected to the same degree. Variation in life histories may explain some of these differences. Here, we examine how abundance of anuran species in roadside habitats is correlated with an aspect of reproductive life history: number of eggs produced by a female per year. Using data from a 1.5-year monitoring project in Central Florida, we found a positive correlation between the number of eggs produced by an average female of a species and the proportion of individuals found in roadside habitats compared to control habitats. This implies either that populations of species with a greater reproductive rate are able to rebound more quickly from negative road impacts, or that there is a strong selective pressure on species with low reproductive rates to avoid roads.

Interactions between the developmental and adult social environments mediate group dynamics and offspring traits in Drosophila melanogaster

Developmental conditions can strongly influence adult phenotypes and social interactions, which in turn affect key evolutionary processes such as sexual selection and sexual conflict. While the implications of social interactions in phenotypically mixed populations at the individual level are increasingly well known, how these effects influence the fate of groups remains poorly understood, which limits our understanding of the broader ecological implications. To address this problem we manipulated adult phenotypes and social composition in Drosophila melanogaster – by experimentally manipulating the larval density of the group-members – and measured a range of group-level outcomes across the lifespan of groups. Adult groups composed of exclusively low larval-density individuals showed high courtship levels, and low early reproductive rates, group growth rates, offspring mass and offspring eclosion success, relative to high larval-density or mixed larval-density groups. Furthermore, high larval-density groups had lower survival. Offspring mass increased with time, but at a reduced rate in groups when male group members (but not females) were from a mixture of larval-densities; peak reproductive rates were also earlier in these groups. Our results suggest that that variation in developmental conditions experienced by adult group members can modify the reproductive output of groups.

Vermiremoval of methylene blue using Eisenia fetida: A potential strategy for bioremediation of synthetic dye-containing effluents

Synthetic dyes from industrial effluents pose significant threats on aquatic and human lives due to its toxic nature. We report removal of synthetic dye Methylene blue (MB) by vermicomposting using earthworm species, Eisenia fetida. The dye adsorbed in sugarcane bagasse (SB) was used as the substrate for vermicomposting. Physico-chemical characterization of compost parameters indicated high quality of vermicomposting. The dye removal from the composted samples was studied by RP-HPLC analysis. In vermicomposted samples, removal of MB was found to be 61% and 98% after 30 and 60 days, respectively. The dye removal was an outcome of combined activities of earthworms and microbes. The dye-stress caused changes in body color and tissue microstructure in earthworms along with lower reproduction rate. However, the worms reverted back to normalcy after removal from vermicomposting and regained reproduction efficacy within 60 days. This study could pave the way for an eco-friendly, inexpensive and promising bioremediation strategy to counter soil contamination due to synthetic dyes effluents.

Morbidity and mortality of middle-aged and elderly narcoleptics

ObjectivesThe objective of the study was to evaluate the morbidities and mortality in a national group of middle-aged and elderly narcolepsy patients before and after the first diagnosis of the condition. MethodsFrom the Danish National Patient Registry (NPR), 1174 patients (45.1% males) aged 20–59 years and 339 patients (44.8% males) aged 60+ who received a diagnosis of narcolepsy between 1998 and 2014 were compared, respectively, with 4716 and 1353 control citizens matched for age, gender and geography, who were randomly chosen from the Danish Civil Registration System Statistics. In the NPR, all morbidities are grouped into major WHO classes. ResultsMiddle-aged and elderly patients had more health contacts before and after their narcolepsy diagnosis with respect to several disease domains: infections, neoplasm, endocrine/metabolic diseases/diabetes, mental/psychiatric, neurological (including epilepsy), eye, cardiovascular (hypertension, ischemic heart disease), respiratory (upper-airway infections, sleep apnea), gastrointestinal, musculoskeletal (including discopathies) and skin diseases. Narcolepsy patients had lower reproductive rates. Furthermore, patients showed significantly more health contacts due to the evaluation and control contacts for disease and symptoms. Patients suffered from significantly more multiple diseases than did controls.The 17-year hazard ratio mortality rates were 1.35 (95% CI, 0.94–1.95, p = 0.106) among 20–59 year-olds, and 1.38 (1.12–1.69, p = 0.002) among those aged 60+ years. ConclusionThere are higher rates of morbidity in several disease domains before and after a diagnosis of narcolepsy. Elderly narcolepsy patients have higher mortality rates.

Oldest Varroa tolerant honey bee population provides insight into the origins of the global decline of honey bees

The ecto-parasitic mite Varroa destructor has transformed the previously inconsequential Deformed Wing Virus (DWV) into the most important honey bee viral pathogen responsible for the death of millions of colonies worldwide. Naturally, DWV persists as a low level covert infection transmitted between nest-mates. It has long been speculated that Varroa via immunosuppression of the bees, activate a covert infection into an overt one. Here we show that despite Varroa feeding on a population of 20–40 colonies for over 30 years on the remote island of Fernando de Noronha, Brazil no such activation has occurred and DWV loads have remained at borderline levels of detection. This supports the alternative theory that for a new vector borne viral transmission cycle to start, an outbreak of an overt infection must first occur within the host. Therefore, we predict that this honey bee population is a ticking time-bomb, protected by its isolated position and small population size. This unique association between mite and bee persists due to the evolution of low Varroa reproduction rates. So the population is not adapted to tolerate Varroa and DWV, rather the viral quasispecies has simply not yet evolved the necessary mutations to produce a virulent variant.

Quantifying the demographic cost of human-related mortality to a raptor population.

Raptors are exposed to a wide variety of human-related mortality agents, and yet population-level effects are rarely quantified. Doing so requires modeling vital rates in the context of species life-history, behavior, and population dynamics theory. In this paper, we explore the details of such an analysis by focusing on the demography of a resident, tree-nesting population of golden eagles (Aquila chrysaetos) in the vicinity of an extensive (142 km2) windfarm in California. During 1994–2000, we tracked the fates of >250 radio-marked individuals of four life-stages and conducted five annual surveys of territory occupancy and reproduction. Collisions with wind turbines accounted for 41% of 88 uncensored fatalities, most of which were subadults and nonbreeding adults (floaters). A consistent overall male preponderance in the population meant that females were the limiting sex in this territorial, monogamous species. Estimates of potential population growth rate and associated variance indicated a stable breeding population, but one for which any further decrease in vital rates would require immigrant floaters to fill territory vacancies. Occupancy surveys 5 and 13 years later (2005 and 2013) showed that the nesting population remained intact, and no upward trend was apparent in the proportion of subadult eagles as pair members, a condition that would have suggested a deficit of adult replacements. However, the number of golden eagle pairs required to support windfarm mortality was large. We estimated that the entire annual reproductive output of 216–255 breeding pairs would have been necessary to support published estimates of 55–65 turbine blade-strike fatalities per year. Although the vital rates forming the basis for these calculations may have changed since the data were collected, our approach should be useful for gaining a clearer understanding of how anthropogenic mortality affects the health of raptor populations, particularly those species with delayed maturity and naturally low reproductive rates.

Low reproductive success rates of common bottlenose dolphins Tursiops truncatus in the northern Gulf of Mexico following the Deepwater Horizon disaster (2010-2015)

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 33:143-158 (2017) - DOI: https://doi.org/10.3354/esr00775 Low reproductive success rates of common bottlenose dolphins Tursiops truncatus in the northern Gulf of Mexico following the Deepwater Horizon disaster (2010-2015) Nicholas M. Kellar1,*, Todd R. Speakman2, Cynthia R. Smith3, Suzanne M. Lane2, Brian C. Balmer2,4, Marisa L. Trego1, Krista N. Catelani1, Michelle N. Robbins1, Camryn D. Allen1, Randall S. Wells4, Eric S. Zolman2, Teresa K. Rowles5, Lori H. Schwacke2 1Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 8901 La Jolla Shores Drive, La Jolla, CA 92037, USA 2Hollings Marine Laboratory, National Centers for Coastal Ocean Science, National Oceanic and Atmospheric Administration, 331 Fort Johnson Road, Charleston, SC 29412, USA 3National Marine Mammal Foundation, 2240 Shelter Island Drive, Suite 200, San Diego, CA 92106, USA 4Chicago Zoological Society, c/o Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236, USA 5Office of Protected Resources, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 1315 East West Highway, Silver Spring, MD 20910, USA *Corresponding author: nick.kellar@noaa.gov ABSTRACT: Following the Deepwater Horizon (DWH) oil spill, reproductive success rates in 2 northern Gulf of Mexico (GoM) bottlenose dolphin stocks exposed to oil were evaluated for 4 yr during and after the spill (2010 to 2015) in efforts to assess population-level reproductive health. Pregnancy was determined from either (1) ultrasound examinations of the reproductive tract during capture-release health assessments, or (2) endocrine evaluations of blubber tissue collected from dart biopsies of free-ranging dolphins. Follow-up photo-identification was then used to track the status of pregnant females and any associated neonatal calves for a minimum of 1 yr after the initial pregnancy detection (IPD). For all pregnant females observed following IPD, individuals seen with a calf (reproductive success) and without one (reproductive failure) were recorded. The resulting estimated reproductive success rates for both GoM stocks (19.4%; 7/36) were less than a third of those previously reported in other areas not impacted by the spill (i.e. Sarasota Bay, FL; Indian River Lagoon, FL; and Charleston Harbor, SC) using similar techniques (64.7%; 22/34). We also evaluated the relationships between reproductive success and 13 potential covariates, including stock, ordinal date, progesterone, cortisol, thyroid hormone concentrations, leukocyte count, lung health score, and total body length. Among these, the results only provide strong evidence (Bayes factor >20) of a relationship between reproductive failure and the total leukocyte count covariate. The high reproductive failure rates measured in both GoM stocks following the DWH oil spill are consistent with mammalian literature that shows a link between petroleum exposure and reproductive abnormalities and failures. KEY WORDS: Oil spill · Petroleum · Pregnancy · Reproductive failure · Cetacean · Blubber progesterone · Ultrasound Full text in pdf format Supplementary material PreviousNextCite this article as: Kellar NM, Speakman TR, Smith CR, Lane SM and others (2017) Low reproductive success rates of common bottlenose dolphins Tursiops truncatus in the northern Gulf of Mexico following the Deepwater Horizon disaster (2010-2015). Endang Species Res 33:143-158. https://doi.org/10.3354/esr00775 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 33. Online publication date: January 31, 2017 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2017 Inter-Research.

An isolated population of the southern scrub-robin (Drymodes brunneopygia) in the Great Victoria Desert

From 2013 to 2015 we recorded an isolated, highly fragmented and previously undocumented population of the southern scrub-robin within the arid shrublands of the Great Victoria Desert. In this region, the southern scrub-robin persists in scattered and intermittent areas of long-unburnt mulga (Acacia spp.) shrubland, with a dense shrubby understorey dominated by Aluta maisonneuvei and Eremophila shrubs. The Great Victoria Desert supports the only known desert population as the southern scrub-robin otherwise occurs in the temperate and semiarid shrublands of southern Australia and occurs in the desert at the arid extreme of its range. Fire is highlighted as a significant threatening process due to the species’ restricted occurrence (less than 5% of the landscape in the region), low reproductive rate, limited dispersal capability and persistence within long-unburnt and fire-sensitive habitats. As forecast environmental changes are likely to render the arid extremes of the species’ range unsuitable, this outlying, desert population is potentially declining and of conservation significance.

Demographic, dispersal, predation and genetic data reveal the potential vulnerability of an endangered rainforest shrub, Triunia robusta (Proteaceae)

We investigated the population ecology of Triunia robusta (C.T. White) Foreman, an endemic rainforest shrub of south-east Queensland, Australia. Two-time demographic data from 1999 and 2010 were used to estimate the species life span and changes in demographic factors over the 11 year period. The potential dispersal vectors and their activities were monitored, and the effects of predation on seed and seedling mortality were quantified. Published genetic data was used to assess the gene flow distance in years. On average, T. robusta has a life span of 103 years, with a generation time of 44 years. Larger populations (&gt;200) increased in size since 1999, whereas smaller populations retained the same or slightly reduced numbers. Small, isolated populations in the northern distribution range showed substantially lower reproductive rates. Local rodents and marsupials were considered responsible for the majority of observed secondary seed dispersal (&lt;10.3 m) and predation activities. Post-predation mortality was high (82%), with only 12% surviving to become seedlings. The empirical evidence of short-distance dispersal, limited gene flow, high post-predation mortality rates and relatively low reproductive rates, combined with potential absence of primary dispersers suggests that critically small and isolated populations may be highly vulnerable.