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At least 235 records · Page 13Linked to original sources
USGS2011

Long-term post-fire effects on spatial ecology and reproductive output of female Agassiz’s desert tortoises ( Gopherus agassizii ) at a wind energy facility near Palm Springs, California, USA

We studied the long-term response of a cohort of eight female Agassiz’s desert tortoises ( Gopherus agassizii ) during the first 15 years following a large fire at a wind energy generation facility near Palm Springs, California, USA. The fire burned a significant portion of the study site in 1995. Tortoise activity areas were mapped using minimum convex polygons for a proximate post-fire interval from 1997 to 2000, and a long-term post-fire interval from 2009 to 2010. In addition, we measured the annual reproductive output of eggs each year and monitored the body condition of tortoises over time. One adult female tortoise was killed by the fire and five tortoises bore exposure scars that were not fatal. Despite predictions that tortoises would make the short-distance movements from burned to nearby unburned habitats, most activity areas and their centroids remained in burned areas for the duration of the study. The percentage of activity area burned did not differ significantly between the two monitoring periods. Annual reproductive output and measures of body condition remained statistically similar throughout the monitoring period. Despite changes in plant composition, conditions at this site appeared to be suitable for survival of tortoises following a major fire. High productivity at the site may have buffered tortoises from the adverse impacts of fire if they were not killed outright. Tortoise populations at less productive desert sites may not have adequate resources to sustain normal activity areas, reproductive output, and body conditions following fire.

California↗
USGS1991

Effect of environment on reproduction and growth of Mysis relicta

Published and unpublished data were examined to determine whether the time to first reproduction, brood size, and growth rate of Mysis relicta are related to environmental conditions. Time to first reproduction ranged from 1 year in eutrophic lakes to 4 years in a ultraoligotrophic lake. Mysids in nutrient-rich lakes may have 45 eggs per brood, whereas those in less productive lakes had 10-12 eggs per brood. Growth rates ranged from 1.0 to 1.5 mm/month in productive lakes to only 0.2 mm/month in ultraoligotrophic Lake Tahoe. Some differences in reproduction and growth rate consistent with the above observation occurred between areas of Lakes Tahoe and Michigan that differed in trophic conditions.

American Fisheries Society Symposium↗
USGS2007

Effects of invasive plant species on pollinator service and reproduction in native plants at Acadia National Park

Invasive plant species can have profound negative effects on natural communities by competively excluding native species. Berberis thunbergii (Japanese barberry), Frangula alnus (glossy or alder buckthorn) and Lythrum salicaria (purple loosestrife) are invasive species known to reduce native plant diversity and are thus of great concern to Acadia National Park. Pollinators visit them for nectar and pollen. The effects of invasive plant species on pollinator behavior were investigated by comparing pollinator visitation to co-flowering native and invasive species with visitation to native species growing alone. The effect of invasives on pollination of native plants was studied by comparing fruit set in patches of the native species growing near invasives with patches far from invasive species in Acadia National Park. The coflowering pairs were as follows: in the spring native Vaccinium angustifolium (lowbush blueberry) was paired with B. thunbergii; in early summer native Viburnum nudum (wild raisin) was paired with F. alnus ; in late summer native Spiraea alba (meadowsweet) was paired with L. salicaria. We investigated whether these invasives competed with native plants for pollinators in Acadia and thus negatively affected native plant reproduction. Our objectives were to determine: 1) the influence, if any, of each invasive on pollinator visitation to a co-flowering native species, 2) factors that might affect visitation, 3) invasive pollen transfer to native plants, and 4) whether invasives influence native plant reproduction (fruit set). Our findings indicate that at times the number of flower visitors to natives was lower or the species composition of visitors different when invasives were present, that invasives sometimes attracted more pollinators, that generally the invasives were more rewarding as far as nectar and pollen availability for pollinators, and that generally native plant fruit set and seed set was not significantly lowered in the presence of the invasive. In fact, in one year fruit set of S. alba was significantly greater in the presence of L. salicaria. The number of invasive pollen grains on native stigmas was extremely low; on average less than one grain per stigma. These fruit set and pollen deposition findings indicate that native plant reproduction was not adversely affected in the short term by these invasive species and that therefore competition between the native and invasive species for pollinators did not occur. Native bee populations monitored in 2004-2005 at sites with and without B. thunbergii and/or F. alnus indicated a greater abundance of native bees at sites with these invasives present. Native bees collected from the native and invasive plants were compared with historical records to assess whether invasive plants favor different bee species than those that formerly predominated on Mount Desert Island. This does not appear to be the case. Several species of bumble bees (Bombus spp.) as well as nine solitary bee species were found that were not documented by the Procter surveys of 1917-1940. Collecting of native bees was limited to the study plants, which may, in part, explain why some bee species documented in the Procter Surveys were not found in the present research. A field guide for identification of native bumble bees has been produced to help Park Natural Resource personnel monitor the status of native bee populations in Acadia. Other educational materials were also developed, aimed at educating Park visitors by exposing them to: 1) the role of native plants and their bee pollinators in terrestrial ecosystems; 2) the effects of invasive plants on native plant-pollinator mutualisms; 3) the need for conserving native bees and other pollinators; and 4) conservation strategies for protecting and enhancing native plant-pollinator mutualisms in the Park. Based on the present findings, Acadia Park Resource Management personnel should continue to closely

Technical Report↗
USGS1985

PCBs, organochlorine pesticides, and reproduction in river otters from Louisiana

Reproductive tracts from 89 3-year-old female river otters (Lutra canadensis), from Louisiana were examined. Eighteen of these were in a reproductive phase out of synchrony with the expected population norms. Eight of 32 otters had fewer embryos than corpora lutea, indicating intrauterine mortality in 25% of the sample. Chemical analyses of liver tissue from 57 otters revealed a low prevalence of polychlorinated biphenyls (PCB) and organochlorine pesticide contamination. These low Ievels of organochlorine compounds were not associated with atypical reproductive synchrony or intrauterine mortality.

Proceedings of the Annual Conference of the Southe↗
USGS2006

Effects of hardness and alkalinity in culture and test waters on reproduction of Ceriodaphnia dubia

Ceriodaphnia dubia were cultured in four reconstituted water formulations with hardness and alkalinity concentrations ranging from soft to the moderately hard water that is required by whole-effluent toxicity (WET) testing methods for culturing test organisms. The effects of these culture formulations alone and in combination with two levels of Cl-, SO42, and HCO3- on reproduction of C. dubia were evaluated with the standard three-brood test. Reproduction was significantly reduced when test waters had lower hardness than culture waters. However, reproduction was not significantly different when animals cultured in low-hardness waters were exposed to moderately hard waters. The hardness of the culture water did not significantly affect the sensitivity of C. dubia to the three anions. Conversely, increased hardness in test waters significantly reduced the toxicities of Cl- and SO42-, with HCO3- toxicity following the same pattern. Alkalinity exhibited no consistent effect on Cl- and SO42- toxicity. The physiological stress of placing animals cultured in moderately hard water into softer test waters might contribute to marginal failures of otherwise nontoxic effluents. The standard WET protocol should be revised to allow the culture of C. dubia under lower hardness conditions to better represent local surface water chemistries.

Environmental Toxicology and Chemistry↗
USGS2011

An overview of estrogen-associated endocrine disruption in fishes: Evidence of effects on reproductive and immune physiology

Simply and perhaps intuitively defined, endocrine disruption is the abnormal modulation of normal hormonal physiology by exogenous chemicals. In fish, endocrine disruption of the reproductive system has been observed worldwide in numerous species and is known to affect both males and females. Observations of biologically relevant endocrine disruption most commonly occurs near waste water treatment plant outfalls, pulp and paper mills, and areas of high organic loading sometimes associated with agricultural practices. Estrogenic endocrine disrupting chemicals (EEDCs) have received an overwhelmingly disproportionate amount of scientific attention compared to other EDCs in recent years. In male fishes, exposure to EEDCs can lead to the induction of testicular oocytes (intersex), measurable plasma vitellogenin protein, altered sex steroid profiles, abnormal spawning behavior, skewed population sex ratios, and lessened reproductive success. Interestingly, contemporary research purports that EDCs modulate aspects of non-reproductive physiology including immune function. Here we present an overview of endocrine disruption in fishes associated with estrogenic compounds, implications of this phenomenon, and examples of EDC related research findings by our group in the Potomac River Watershed, USA.

Conference Paper↗
USGS2006

The role of reproductive behavior in the conservation of fishes: examples from the Great Plains riverine fishes

Recovery efforts for threatened and endangered fish species are hampered by lack of knowledge of their reproductive ecology. Habitat requirements and environmental stimuli necessary for reproduction are often unknown and vary widely among species. For Great Plains riverine fishes, this is often complicated by the high turbidity of the system in which the species occur, which precludes direct visual observation of behavior. Innovative methods for collectng behavioral data are required to better understand the conditions necessary for successful reproduction.

American Currents↗
USGS2017

Time within reproductive season, but not age or inbreeding coefficient, influences seminal and sperm quality in the whooping crane (Grus americana)

All living whooping cranes ( Grus americana ) are descended from 16 or fewer birds that remained alive in the early 1940s, a bottleneck that puts the species at potential risk for inbreeding depression. Although AI is commonly used in the management of the captive population of this species, little is known about seminal traits or factors affecting sperm quality in the whooping crane. In the present study, semen samples were collected from 29 adult males (age 3–27 years) during the early (March), mid (April) and late (May) breeding season over 2 consecutive years. The effects of donor age, time within reproductive season and level of inbreeding on seminal characteristics were analysed using regression and information–theoretic model selection. Only time within reproductive season significantly affected seminal traits, with total numbers of spermatozoa and proportions of pleiomorphisms increasing across the season. We conclude that, even with a highly restricted number of founders, there is no discernible influence of inbreeding (at the levels described) on sperm output or quality. Furthermore, although there is variance in seminal quality, the whooping crane produces significant numbers of motile spermatozoa throughout the breeding season, similar to values reported for the greater sandhill crane ( Grus canadensis tabida ).

Reproduction, Fertility and Development↗
USGS1992

The zebra mussel (Dreissena polymorpha), a new pest in North America: reproductive mechanisms as possible targets of control strategies

The zebra mussel (Dreissena polymorpha) has spread rapidly in temperate fresh waters of North America since its introduction into the Great Lakes in 1985 or 1986. It attaches to hard substrates, forming layers, occluding water intakes, encrusting and killing native mussels, filtering algae in competition with other planktivores, and possibly interfering with fish spawning. It reproduces prolifically, suggesting that an approach to its control may be by controlling its reproduction. Previous literature suggests that spawning in bivalves is regulated by both environmental and internal chemical cues. A suggested sequence is that phytoplankton chemicals initially trigger spawning; chemicals associated with gametes provide a species-specific pheromonal positive feedback for spawning; and the response to environmental chemicals is mediated internally by serotonin (5-HT). The role of 5-HT in zebra mussels is under investigation. Both males and females can be induced to spawn by either injection or external application of 5-HT. The response can also be activated by 8-hydroxy-2-(di-n-propylamino)-tetralin, an agonist at 5-HT 1A receptors. HPLC analysis has detected 5-HT as the major biogenic amine in both male and female gonads. 5-HT immunocytochemistry demonstrates nerves containing serotonergic fibers innervating gonads of both males and females, with prominent varicosities surrounding the follicles in both sexes. A role of 5-HT in mediating spawning responses in zebra mussels is thus strongly supported. These studies have shown that reproductive behavior of zebra mussels can be modified by outside chemicals, a property that may be exploited for purposes of control.

Invertebrate Reproduction and Development↗
USGS2017

Temporal constraints on the potential role of fry odors as cues of past reproductive success for spawning lake trout

Deciding where to reproduce is a major challenge for most animals. Many select habitats based upon cues of successful reproduction by conspecifics, such as the presence of offspring from past reproductive events. For example, some fishes select spawning habitat following odors released by juveniles whose rearing habitat overlaps with spawning habitat. However, juveniles may emigrate before adults begin to search for spawning habitat; hence, the efficacy of juvenile cues could be constrained by degradation or dissipation rates. In lake trout ( Salvelinus namaycush ), odors deposited by the previous year's offspring have been hypothesized to guide adults to spawning reefs. However, in most extant populations, lake trout fry emigrate from spawning reefs during the spring and adults spawn during the fall. Therefore, we postulated that the role of fry odors in guiding habitat selection might be constrained by the time between fry emigration and adult spawning. Time course chemical, physiological, and behavioral assays indicated that the odors deposited by fry likely degrade or dissipate before adults select spawning habitats. Furthermore, fry feces did not attract wild lake trout to constructed spawning reefs in Lake Huron. Taken together, our results indicate fry odors are unlikely to act as cues for lake trout searching for spawning reefs in populations whose juveniles emigrate before the spawning season, and underscore the importance of environmental constraints on social cues.

Ecology and Evolution↗
USGS2020

RAPTURE (RAD capture) panel facilitates analyses characterizing sea lamprey reproductive ecology and movement dynamics

Genomic tools are lacking for invasive and native populations of sea lamprey ( Petromyzon marinus ). Our objective was to discover single nucleotide polymorphism (SNP) loci to conduct pedigree analyses to quantify reproductive contributions of adult sea lampreys and dispersion of sibling larval sea lampreys of different ages in Great Lakes tributaries. Additional applications of data were explored using additional geographically expansive samples. We used restriction site‐associated DNA sequencing (RAD‐Seq) to discover genetic variation in Duffins Creek (DC), Ontario, Canada, and the St. Clair River (SCR), Michigan, USA. We subsequently developed RAD capture baits to genotype 3,446 RAD loci that contained 11,970 SNPs. Based on RAD capture assays, estimates of variance in SNP allele frequency among five Great Lakes tributary populations (mean F ST 0.008; range 0.00–0.018) were concordant with previous microsatellite‐based studies; however, outlier loci were identified that contributed substantially to spatial population genetic structure. At finer scales within streams, simulations indicated that accuracy in genetic pedigree reconstruction was high when 200 or 500 independent loci were used, even in situations of high spawner abundance (e.g., 1,000 adults). Based on empirical collections of larval sea lamprey genotypes, we found that age‐1 and age‐2 families of full and half‐siblings were widely but nonrandomly distributed within stream reaches sampled. Using the genomic scale set of SNP loci developed in this study, biologists can rapidly genotype sea lamprey in non‐native and native ranges to investigate questions pertaining to population structuring and reproductive ecology at previously unattainable scales.

Michigan, Ontario, Wisconsin↗
USGS2023

Reproductive response of the Samoan swallowtail butterfly to variability in host plant and habitat characteristics

The Samoan swallowtail butterfly ( Papilio godeffroyi ) has become restricted to Tutuila Island, American Samoa. Factors driving its extirpation on other islands may be partly due to the availability and suitability of habitat, given the singular association we observed of P. godeffroyi with its host plant, Micromelum minutum. We expected that as a host plant specialist, P. godeffroyi might respond to variation in the physical traits and habitat context of M. minutum , which could help identify conservation opportunities throughout its present and former range. Because the ecology of P. godeffroyi is largely unknown, we conducted systematic surveys during 15 months in 2013 and 2014 on Tutuila to investigate its reproductive response to the physical and phenological variability of individual host trees and to the structural and geographical variability of the stands in which they occurred. We searched foliage for eggs, larvae, and pupae and monitored seasonal trends in herbivory and production of leaves, flowers, and fruits on 117 host trees in 8 rainforest stands, mostly within the National Park of American Samoa (NPSA), starting in March 2013 and ending in August 2014. We observed high variability in butterfly reproductive output between individual trees and stands, due largely to a strong negative relationship between leaf biomass (at both tree and stand levels) and oviposition density (number of eggs per foliar biomass) and frequency (number of eggs per survey). Distribution patterns of larvae and pupae were less distinct but generally followed trends in oviposition. Our findings indicate that the butterfly is reproducing widely across Tutuila and is likely to respond positively to management to increase the availability of small host trees in low-density stands. Thus, the species is a good candidate for conservation management focusing on habitat.

Tutuila Island↗
USGS2023

Effect of straying, reproductive strategies, and ocean distribution on the structure of American shad populations

The use of species distribution models has proliferated, providing insights for sustainable management of migratory species in a globally changing environment. However, many of these models are based on statistical relationships developed from historical conditions that may not perform well under changing or even analogous conditions caused by climate change. In this paper, we used a mechanistic species distribution model called GR3D (Global Repositioning Dynamics for Diadromous Fish Distribution) to examine the integrated dynamics of American shad ( Alosa sapidissima ) populations across their native range along the Eastern U.S. coast, where the species demonstrates latitudinal variations in life histories and reproductive strategies. The initial design of the model was adapted to incorporate region-specific parameterization to fit the species ecology. Then, a sensitivity analysis was performed to test the influences of uncertain processes regarding American shad distribution at sea, straying and reproduction on key characteristics of the species distribution. The sensitivity analysis showed the influence of the Allee effect (i.e., “depensatory” process) and the homing rate (i.e., fidelity to the breeding sites) on the probability of presence and abundances among catchments and metapopulations estimated by the model. Contrary to the homing rate, the distance of straying did not change the estimated number of metapopulations or abundances. Homing strength, however, was quite influential. The integration of complex migration patterns during the marine phase (i.e., wintering and summering offshore areas) provided more likely estimates of the species' overall distribution. Overall, our study illustrated the utility of incorporating factors governing the large-scale distribution of migratory species to improve local management.

Ecosphere↗
USGS2024

Reproductive ecology and egg parasitism of the Samoan swallowtail butterfly

We investigated the reproductive ecology and effects of egg parasitism on the Samoan swallowtail butterfly ( Papilio godeffroyi ), which survives only on Tutuila Island, American Samoa, after having disappeared from the much larger islands of Upolu and Savai‘i in independent Samoa. During monthly surveys of its only known host plant, Micromelum minutum , across eight sites in 2013 and 2014, we collected eggs, eggshells, larvae, pupae, and pupal exuviae. Live specimens were reared under laboratory conditions to determine reproductive outcomes, developmental rates, and sex ratios, as well as parasitoid attack frequencies, brood sizes, and sex ratios. Sixty-six of 448 (14.7%) eggs produced larvae, 47 of which became adults. The sex ratio was approximately even overall and within each developmental stage. Eggs were slightly larger on individual host trees and in host tree stands that yielded more eggs per unit of foliage, indicating that ovipositing females responded to some features of host trees and stands. Eggs hatching female or male larvae were similar in size, and the sexes developed at similar rates. A newly described species of parasitoid wasp, Ooencyrtus pitosina (Encyrtidae), emerged from 73.6% of 382 butterfly eggs that failed to hatch in the laboratory (62.7% of 448 eggs overall). Forty-one other eggs contained dead parasitoid larvae. An additional, unidentified Ooencyrtus wasp species emerged from a single P. godeffroyi egg. No parasitoids were reared from P. godeffroyi larvae or pupae. Of 656 P. godeffroyi eggshells collected in the field and examined in the laboratory, 62.2% showed signs of having been parasitized by O. pitosina. There was no evidence that parasitism rates were density-dependent. O. pitosina brood sizes ranged from 1 to 5, with the sex ratio skewed toward females (2.40 F:1.00 M). Larger parasitoid broods were associated with slightly larger host eggs, indicating that female wasps may adjust brood size according to host egg size or that fewer wasp larvae are able to complete development in smaller eggs. Techniques used to rear both P. godeffroyi and O. pitosina in the laboratory could be applied to a captive-rear, wild-release program, which may facilitate reestablishment of the species in Samoa.

Tutuila Island↗
USGS2025

Predator-induced injury of a neonatal pronghorn cues abandonment of current reproductive investment

Evolutionary theory predicts that parental care is favored when the fitness benefits outweigh the costs of providing care (Klug et al., 2012 ). In mammals, parental care is generally provided by females, who provide nourishment through lactation, protection from predators, aid in juvenile movement, or otherwise facilitate offspring survival (Balshine, 2012 ; Lent, 1974 ). However, in capital breeding species that rely on stored energy reserves for reproduction, increased investment can reduce the female's body condition and the number of offspring produced in subsequent years (Balme et al., 2017 ; Cook et al., 2013 ; Stephens et al., 2009 ). Unlike income breeders, which produce offspring from concurrent energy uptake, capital breeders deplete energy stores during reproduction, and lactation hinders the recovery of these stores (Clutton-Brock et al., 1983 ; Cook et al., 2013 ; Stephens et al., 2009 ). Consequently, iteroparous mammals face a trade-off between investing in current offspring and investing in maintenance or future offspring (Hamel et al., 2010 ; Stearns, 1989 ; Williams, 1966 ).

Ecology↗
USGS2018

Polychlorinated biphenyl tissue‐concentration thresholds for survival, growth, and reproduction in fish

Polychlorinated biphenyls (PCBs) have left a legacy of environmental contamination. Even though they were banned from production and active use in the 1970s, they persist in the environment and still have the potential to impact aquatic life. Our objective was to identify data from controlled laboratory studies of PCB‐related adverse effects in fish and to conduct a meta‐analysis on mortality, growth, and reproductive (MGR) threshold responses. For each endpoint type, we compiled data on the lowest‐observed‐adverse effect concentration (LOAEC) and the degree of effect at the LOAEC as a percentage of control. The LOAECs were expressed as tissue concentrations, so the term lowest‐observed‐adverse‐effect residue concentration (LOAER) was used to represent PCB exposures. The lower limit of applicability was set at 0.1 μg/g total PCB tissue concentration, below which adverse MGR effects in fish were not supported by the data. Sensitivity distributions identifying the probability of adverse effects in fish populations or communities predicted that 25% of fish species would be impacted between 0.1 and 7.5 μg/g. Concentration–response threshold regressions were developed from the MGR datasets. For example, a 1 μg/g total PCB tissue concentration would predict effects of 17% mortality, 15% growth, and 39% reproductive. The analysis determined the degree of adverse response, with uncertainty estimates, expected across a broad range of PCB tissue exposure concentrations in fish. Data generated from MGR endpoints were combined to determine an approach for overall effect thresholds for PCB‐related injury in fish. The MGR datasets included only laboratory data; however, responses were compared with field‐observed effects. The present review provides a comprehensive assessment of PCB‐induced injury in fish utilizing a data‐inclusive approach.

Environmental Toxicology and Chemistry↗
USGS2001

Impact of vinclozolin on reproductive behavior and endocrinology in Japanese quail (Coturnix coturnix japonica)

The impact of endocrine-disrupting chemicals (EDCs) has been demonstrated in mammalian models, but less research is available for avian species. The effects of vinclozolin (VIN), an antiandrogenic fungicide, on sexual differentiation and maturation were investigated in Japanese quail ( Coturnix coturnix japonica ). On day 4 of incubation, embryos were exposed to no treatment, oil, or 25, 50, or 100 ppm of VIN. Endpoints measured included adult male reproductive behavior, hypothalamic gonadotropin-releasing hormone I (GnRH-I) content in hatchlings and adults, plasma steroid levels in hatchlings and adults, proctodeal gland growth during maturation, and relative testicular weight at seven weeks of age. Results showed that exposure to VIN significantly ( p < 0.05) altered GnRH-I in male hatchlings, whereas GnRH-I levels in females remained unaffected. Although steroid levels were unaltered by any VIN treatment, the display of male reproductive behavior seemed delayed, with the number of mounts and the number of cloacal contacts being significantly ( p < 0.05) lower in the VIN-treated males. This could have an extreme negative impact on wild avian species that are routinely exposed to similar EDCs.

Environmental Toxicology and Chemistry↗
USGS2024

Effects of release strategy, source population, and age on reintroduced scaled quail reproduction

Translocation is one strategy to reestablish populations of scaled quail ( Callipepla squamata ). Initial reproductive success post-translocation is important for establishing short-lived species such as quail, but factors influencing reproductive success are poorly understood. We evaluated the effect of source population and variation in delayed release strategy (1−9 weeks) on nest initiation and nest survival of wild-caught, translocated scaled quail. We trapped and translocated scaled quail in 2016–2017 from source populations in the Edwards Plateau and Rolling Plains ecoregions of Texas, USA, to a large contiguous (>40,000 ha) release site in Knox County, Texas. We used a multi-state mark-recapture model with state uncertainty to test for effects of release treatment, source population, age, release location, and year on nest initiation and survival. Increased length of holding time decreased re-nesting effort. Yearlings were more likely to initiate nests than adults and the probability of re-nesting was lower during the year with drought conditions. There was no effect of source population on any of the parameters we evaluated. Future scaled quail reintroduction efforts may benefit from prioritizing translocation of yearlings and conducting translocations when drought conditions are not forecasted.

Texas↗