scholarly journals Fluctuations in food supply drive recruitment variation in a marine fish

2012 ◽  
Vol 279 (1747) ◽  
pp. 4542-4550 ◽  
Author(s):  
Daniel K. Okamoto ◽  
Russell J. Schmitt ◽  
Sally J. Holbrook ◽  
Daniel C. Reed
Keyword(s):  
Food Supply ◽  
Reference Points ◽  
Model Systems ◽  
Conservation Strategies ◽  
Vital Rates ◽  
Animal Populations ◽  
Order Of Magnitude ◽  
Prey Resources ◽  
Magnitude Variation ◽  
Reproductive Rates

Reproductive rates and survival of young in animal populations figure centrally in generating management and conservation strategies. Model systems suggest that food supply can drive these often highly variable properties, yet for many wild species, quantifying such effects and assessing their implications have been challenging. We used spatially explicit time series of a well-studied marine reef fish (black surfperch Embiotoca jacksoni ) and its known prey resources to evaluate the extent to which fluctuations in food supply influenced production of young by adults and survival of young to subadulthood. Our analyses reveal: (i) variable food available to both adults and to their offspring directly produced an order of magnitude variation in the number of young-of-year (YOY) produced per adult and (ii) food available to YOY produced a similar magnitude of variation in their subsequent survival. We also show that such large natural variation in vital rates can significantly alter decision thresholds (biological reference points) important for precautionary management. These findings reveal how knowledge of food resources can improve understanding of population dynamics and reduce risk of overharvest by more accurately identifying periods of low recruitment.

scholarly journals Mineralogical, numerical and analytical studies of the coupled oxidation of pyrite and coal

2003 ◽  
Vol 67 (2) ◽  
pp. 381-398 ◽  
Author(s):  
K. A. Evans ◽  
C. J. Gandy ◽  
S. A. Banwart
Keyword(s):  
Reactive Transport ◽  
Transport Model ◽  
Pyrite Oxidation ◽  
Spoil Heap ◽  
Reaction Fronts ◽  
Order Of Magnitude ◽  
Magnitude Variation ◽  
Discharge Chemistry ◽  
Analytical Expressions

Mineralogical, bulk and field leachate compositions are used to identify important processes governing the evolution of discharges from a coal spoil heap in County Durham. These processes are incorporated into a numerical one-dimensional advective-kinetic reactive transport model which reproduces field results, including gas compositions, to within an order of magnitude. Variation of input parameters allows the effects of incorrect initial assumptions on elemental profiles and discharge chemistry to be assessed. Analytical expressions for widths and speeds of kinetic reaction fronts are developed and used to predict long-term development of mineralogical distribution within the heap. Results are consistent with observations from the field site. Pyrite oxidation is expected to dominate O2 consumption in spoil heaps on the decadal timescale, although C oxidation may stabilize contaminants in effluents on the centennial scale.

scholarly journals Effects of Climate and Biotic Factors on Life History Characteristics and Vital Rates of Yellowstone Cutthroat Trout in Spread Creek, Wyoming

2013 ◽  
Vol 36 ◽  
pp. 160-174
Author(s):  
Patrick Uthe ◽  
Robert Al-Chokhachy
Keyword(s):  
Life History ◽  
Brook Trout ◽  
Cutthroat Trout ◽  
Conservation Strategies ◽  
Snake River ◽  
Vital Rates ◽  
Factors Influencing ◽  
Yellowstone Cutthroat Trout ◽  
Life History Patterns ◽  
Diversity Of Life

The Upper Snake River represents one of the largest remaining strongholds of Yellowstone cutthroat across its native range. Understanding the effects of restoration activities and the diversity of life-history patterns and factors influencing such patterns remains paramount for long-term conservation strategies. In 2011, we initiated a project to quantify the success of the removal of a historic barrier on Spread Creek and to evaluate the relative influence of different climate attributes on native Yellowstone cutthroat trout and non-native brook trout behavior and fitness. Our results to date have demonstrated the partial success of the dam removal with large, fluvial Yellowstone cutthroat trout migrating up Spread Creek to spawn, thus reconnecting this population to the greater Snake River metapopulation. Early indications from mark-recapture data demonstrate considerable differences in life-history and demographic patterns across tributaries within the Spread Creek drainage. Our results highlight the diversity of life-history patterns of resident and fluvial Yellowstone cutthroat trout with considerable differences in seasonal and annual growth rates and behavior across populations. Continuing to understand the factors influencing such patterns will provide a template for prioritizing restoration activities in the context of future challenges to conservation (e.g., climate change).

scholarly journals Changes in landscape composition influence the decline of a threatened woodland caribou population

2020 ◽  
Author(s):  
Heiko Wittmer ◽  
B McLellan ◽  
R Serrouya ◽  
C Apps
Keyword(s):  
Large Scale ◽  
Spatial Scales ◽  
Apparent Competition ◽  
Timber Harvesting ◽  
Conservation Strategies ◽  
Home Ranges ◽  
Vital Rates ◽  
Population Declines ◽  
Woodland Caribou ◽  
Habitat Alterations

Large-scale habitat loss is frequently identified with loss of biodiversity, but examples of the direct effect of habitat alterations on changes in vital rates remain rare. Quantifying and understanding the relationship between habitat composition and changes in vital rates, however, is essential for the development of effective conservation strategies. It has been suggested that the decline of woodland caribou Rangifer tarandus caribou populations in North America is precipitated by timber harvesting that creates landscapes of early seral forests. Such habitat changes have altered the predator-prey system resulting in asymmetric predation, where predators are maintained by alternative prey (i.e. apparent competition). However, a direct link between habitat condition and caribou population declines has not been documented. We estimated survival probabilities for the threatened arboreal lichen-feeding ecotype of woodland caribou in British Columbia, Canada, at two different spatial scales. At the broader scale, observed variation in adult female survival rates among 10 distinct populations (range = 0.67-0.93) was best explained by variation in the amount of early seral stands within population ranges and population density. At the finer scale, home ranges of caribou killed by predators had lower proportions of old forest and more mid-aged forest as compared with multi-annual home ranges where caribou were alive. These results are consistent with predictions from the apparent competition hypothesis and quantify direct fitness consequences for caribou following habitat alterations. We conclude that apparent competition can cause rapid population declines and even extinction where changes in species composition occur following large scale habitat change. © 2007 The Authors. Journal compilation © 2007 British Ecological Society.

scholarly journals Strength Tests on Newly Fallen Snow

1969 ◽  
Vol 8 (54) ◽  
pp. 427-440 ◽  
Author(s):  
R. Perla
Keyword(s):  
Cone Penetrometer ◽  
Light Weight ◽  
Large Drop ◽  
Torque Wrench ◽  
Strength Tests ◽  
Order Of Magnitude ◽  
Magnitude Variation ◽  
A New Technique ◽  
Shear Frame

AbstractModified versions ofin situstrength tests previously applied to metamorphosed snow were developed to measure the mechanical properties of newly fallen snow during storm periods. A large drop-cone penetrometer, protected from the wind by an aluminum shell, was used to determine snow “hardness”. A lightweight model of the Haefeli ram penetrometer measured “ram numbers”. Shear strengths were obtained from large, light-weight frames. Some preliminary tests were made with a shear vane driven by a torque wrench. A new technique was devised for measuring tensile strength whereby a cantilever beam of snow is undercut until it fails under its own weight. Comparisons between the cantilever test and the shear-frame test show high ratios for tensile to shear strength. Cantilever strength plotted against density shows an order of magnitude variation in strength at all densities.

scholarly journals Evaluating the impacts of fishing on sex-changing fish: a game-theoretic approach

2016 ◽  
Vol 74 (3) ◽  
pp. 652-659 ◽  
Author(s):  
Orin J. Robinson ◽  
Olaf P. Jensen ◽  
Mikaela M. Provost ◽  
Shuochen Huang ◽  
Nina H. Fefferman ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Sex Change ◽  
Fertilization Rate ◽  
Maximum Sustainable Yield ◽  
Reference Points ◽  
Life History Trait ◽  
Theoretic Approach ◽  
Vital Rates ◽  
Game Theoretic ◽  
Game Theoretic Approach

Abstract Sex change has been widely documented in many commercially and recreationally important fish species, yet the implications of this life history trait are not considered in most stock assessments. This omission can lead to poor estimates of parameters vital to understanding the health of sequentially hermaphroditic stocks. Here, we present a game theoretic approach to model the sex changing behaviour of a stock of protogynous (female first) hermaphroditic fish and produce estimates of maximum sustainable yield (MSY), equilibrium biomass at MSY (BMSY) and sex ratio, then compare these reference points to those from an otherwise identical gonochoristic (non-sex changing) stock. We tested each stock at varying levels of exploitation and with a range of assumptions about how sex ratio impacts fertilization rate. We show that a protogynous hermaphroditic stock with flexible timing of sex change produces similar MSY and slightly higher BMSY than a gonochoristic stock with otherwise identical vital rates. Sex changing stocks were also able to maintain a higher proportion of males in the population than did non-sex changing stocks as exploitation increased. Although sex changing stocks were able to maintain their sex ratio, the age at which females changed sex decreased with increased exploitation, suggesting smaller body size, and presumably lower fecundity, for females in heavily exploited sex changing stocks. Our game theoretic approach to evaluating hermaphroditic stocks can accommodate a wide variety of sex changing cues and behaviours and allows a flexible model for understanding the effects of exploitation on hermaphroditic stocks.

scholarly journals Predicting the zoonotic capacity of mammals to transmit SARS-CoV-2

2021 ◽  
Vol 288 (1963) ◽  
Author(s):  
Ilya R. Fischhoff ◽  
Adrian A. Castellanos ◽  
João P. G. L. M. Rodrigues ◽  
Arvind Varsani ◽  
Barbara A. Han
Keyword(s):  
Protein Interactions ◽  
Three Dimensional ◽  
Predictive Modelling ◽  
Molecular Data ◽  
Transmission Risk ◽  
Virus Protein ◽  
Biological Traits ◽  
Animal Populations ◽  
Order Of Magnitude

Back and forth transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) between humans and animals will establish wild reservoirs of virus that endanger long-term efforts to control COVID-19 in people and to protect vulnerable animal populations. Better targeting surveillance and laboratory experiments to validate zoonotic potential requires predicting high-risk host species. A major bottleneck to this effort is the few species with available sequences for angiotensin-converting enzyme 2 receptor, a key receptor required for viral cell entry. We overcome this bottleneck by combining species' ecological and biological traits with three-dimensional modelling of host-virus protein–protein interactions using machine learning. This approach enables predictions about the zoonotic capacity of SARS-CoV-2 for greater than 5000 mammals—an order of magnitude more species than previously possible. Our predictions are strongly corroborated by in vivo studies. The predicted zoonotic capacity and proximity to humans suggest enhanced transmission risk from several common mammals, and priority areas of geographic overlap between these species and global COVID-19 hotspots. With molecular data available for only a small fraction of potential animal hosts, linking data across biological scales offers a conceptual advance that may expand our predictive modelling capacity for zoonotic viruses with similarly unknown host ranges.

scholarly journals Microarthropod contributions to fitness variation in the common moss Ceratodon purpureus

2021 ◽  
Vol 288 (1947) ◽  
Author(s):  
Erin E. Shortlidge ◽  
Sarah B. Carey ◽  
Adam C. Payton ◽  
Stuart F. McDaniel ◽  
Todd N. Rosenstiel ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Rank Order ◽  
Model Systems ◽  
Interacting Species ◽  
Pooled Sequencing ◽  
Experimental Mesocosms ◽  
The Common ◽  
Plant Animal Interactions ◽  
Reproductive Rates

The evolution of sustained plant–animal interactions depends critically upon genetic variation in the fitness benefits from the interaction. Genetic analyses of such interactions are limited to a few model systems, in part because genetic variation may be absent or the interacting species may be experimentally intractable. Here, we examine the role of sperm-dispersing microarthropods in shaping reproduction and genetic variation in mosses. We established experimental mesocosms with known moss genotypes and inferred the parents of progeny from mesocosms with and without microarthropods, using a pooled sequencing approach. Moss reproductive rates increased fivefold in the presence of microarthropods, relative to control mesocosms. Furthermore, the presence of microarthropods increased the total number of reproducing moss genotypes, and changed the rank-order of fitness of male and female moss genotypes. Interestingly, the genotypes that reproduced most frequently did not produce sporophytes with the most spores, highlighting the challenge of defining fitness in mosses. These results demonstrate that microarthropods provide a fitness benefit for mosses, and highlight the potential for biotic dispersal agents to alter fitness among moss genotypes.

scholarly journals Hydrogen bond simulation in molecular crystals of tyrosine

2019 ◽  
Vol 58 (6) ◽  
pp. 73-77
Author(s):  
Tatiana G. Volkova ◽  
◽  
Irina O. Talanova ◽  
Keyword(s):  
Amino Acids ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Interaction Energy ◽  
Biologically Active ◽  
Model Systems ◽  
Significant Difference ◽  
Molecular Associate ◽  
Order Of Magnitude ◽  
Chemical Simulation

The problem of the study of hydrogen bonds in biomolecules and living systems is important. Among the drugs, doctors emphasize substances of natural origin involved in metabolic processes. Such compounds include amino acids, peptides, vitamins, enzymes, macro- and microelements, and other biologically active substances, many of which are capable of forming hydrogen bonds. Amino acids and their derivatives are drugs of metabolic pharmacotherapy, characterized by low toxicity and severity of side effects. They also have virtually no allergenic effect, which makes them promising for the creation of drugs or their modifications. The instability of the hydrogen bond can significantly affect the state of pharmaceutical drug containing, for example, amino acids, during their storage, transportation or technological processing. One of the methods for studying the nature and determining the strength of hydrogen bonds is quantum chemical simulation. The calculation of the interaction energy in the studied molecular associate and its decomposition have been carried out according to Morocuma’s method (HF/6-31G (PC GAMESS). The evaluation of such energy components as electrostatic, exchange repulsion, polarization, charge transfer, mixing is given. The main contribution to the interaction energy comes from the electrostatic component. All the studied models have the same distribution of the components of the interaction energy in order of magnitude. Significant difference in the interaction energy in two model systems was noted, that could be explained by different geometry of hydrogen bonds. The comparison of received data made it possible to conclude that there are three types of hydrogen bonds in the molecular tyrosine crystal, which differ from each other in energy and geometry.

scholarly journals Assessment of fecal steroid and thyroid hormone metabolites in eastern North Pacific gray whales

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Leila S Lemos ◽  
Amy Olsen ◽  
Angela Smith ◽  
Todd E Chandler ◽  
Shawn Larson ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
North Pacific ◽  
Reference Points ◽  
Future Research ◽  
Vital Rates ◽  
Baleen Whale ◽  
Gray Whales ◽  
Fecal Steroid ◽  
Metabolite Concentrations ◽  
The Impact

Abstract Baleen whale fecal samples have high potential for endocrine monitoring, which can be used as a non-invasive tool to identify the physiological response to disturbance events and describe population health and vital rates. In this study, we used commercial enzyme-linked immunosorbent assays to validate and quantify fecal steroid (progestins, androgens and glucocorticoids) and thyroid hormone metabolite concentrations in eastern North Pacific gray whales (Eschrichtius robustus) along the Oregon coast, USA, from May to October of 2016–2018. Higher mean progestin metabolite concentrations were observed in postweaning females, followed by pregnant females. Mean androgen, glucocorticoid and thyroid metabolites were higher in mature males. Progestin, glucocorticoids and thyroid fecal metabolites varied significantly by year, with positive correlations between progestin and androgen, and between glucocorticoid and thyroid metabolites. We also present two case studies of a documented injured whale and a mature male displaying reproductive competitive behavior, which provide reference points for physiologically stressed individuals and adult breeding males, respectively. Our methods and findings advance the knowledge of baleen whale physiology, can help guide future research on whale physiology and can inform population management and conservation efforts regarding minimizing the impact of anthropogenic stressors on whales.

Climate-induced variation in vital rates of an unharvested large-herbivore population

2003 ◽  
Vol 81 (1) ◽  
pp. 33-45 ◽  
Author(s):  
Robert A Garrott ◽  
L Lee Eberhardt ◽  
Patrick J White ◽  
Jay Rotella
Keyword(s):  
Cervus Elaphus ◽  
Dynamic Equilibrium ◽  
Survival Rates ◽  
Vital Rates ◽  
Large Herbivore ◽  
Stochastic Effects ◽  
Resource Limited ◽  
Historic Data ◽  
Reproductive Rates ◽  
Variable Recruitment

Variation in vital rates of an unharvested elk (Cervus elaphus) population was studied using telemetry for 7 consecutive years, 1991–1998. We found pronounced senescence in survival rates, but no evidence for reproductive senescence. Prime-age females (<10 years old) experienced very high annual survival rates (mean = 0.97, SE = 0.02), with lower survival rates for senescent animals ([Formula: see text]10 years old; mean = 0.79, SE = 0.06). There was evidence that the severity of snowpack conditions had little effect on survival of prime-age animals except during the most extreme winter, while survival of senescent animals was progressively depressed as the severity of snowpack conditions increased. Reproductive rates remained essentially constant, near their biological maxima (mean = 0.91, SE = 0.02). Annual re cruitment was highly variable. Snowpack had a pronounced effect on recruitment (r2 = 0.91), the most severe snowpack conditions resulting in the virtual elimination of a juvenile cohort. Population estimates and recruitment rates obtained during this investigation and historic data collected from 1965 to 1980 support the premise that the population has been maintained in a dynamic equilibrium for at least three decades despite the stochastic effects of climate variation on vital rates. We conclude that the population is resource-limited, with variation about the equilibrium caused primarily by variable recruitment driven by stochastic annual snowpack.

Sign in / Sign up

Export Citation Format

Share Document