Unusually High Reproductive Effort by Sage Grouse in a Fragmented Habitat in North-Central Washington

The Condor ◽  
1997 ◽  
Vol 99 (4) ◽  
pp. 933 ◽  
Author(s):  
Michael A. Schroeder
Keyword(s):  
Reproductive Effort ◽  
Sage Grouse ◽  
North Central ◽  
Fragmented Habitat ◽  
High Reproductive Effort

High Reproductive Effort and Low Recruitment Rates of European Beech: Is There a Limit for the Superior Competitor?

2015 ◽  
Vol 63 (2) ◽  
pp. 198-212 ◽  
Author(s):  
Jerzy Szwagrzyk ◽  
Georg Gratzer ◽  
Hanna Stępniewska ◽  
Janusz Szewczyk ◽  
Bojana Veselinovic
Keyword(s):  
Reproductive Effort ◽  
European Beech ◽  
High Reproductive Effort

scholarly journals Machine Learning for Conservation Planning in a Changing Climate

2020 ◽  
Vol 12 (18) ◽  
pp. 7657
Author(s):  
Ana Cristina Mosebo Fernandes ◽  
Rebeca Quintero Gonzalez ◽  
Marie Ann Lenihan-Clarke ◽  
Ezra Francis Leslie Trotter ◽  
Jamal Jokar Arsanjani
Keyword(s):  
Climate Change ◽  
Machine Learning ◽  
Machine Learning Algorithms ◽  
Climate Projections ◽  
Sage Grouse ◽  
Climate Conditions ◽  
Fragmented Habitat ◽  
Related Data ◽  
Temperature And Precipitation ◽  
Methodical Approach

Wildlife species’ habitats throughout North America are subject to direct and indirect consequences of climate change. Vulnerability assessments for the Intermountain West regard wildlife and vegetation and their disturbance as two key resource areas in terms of ecosystems when considering climate change issues. Despite the adaptability potential of certain wildlife, increased temperature estimates of 1.67–2 °C by 2050 increase the likelihood and severity of droughts, floods, heatwaves and wildfires in Utah. As a consequence, resilient flora and fauna could be displaced. The aim of this study was to locate areas of habitat for an exemplary species, i.e., sage-grouse, based on current climate conditions and pinpoint areas of future habitat based on climate projections. The locations of wildlife were collected from Volunteered Geographic Information (VGI) observations in addition to normal temperature and precipitation, vegetation cover and other ecosystem-related data. Four machine learning algorithms were then used to locate the current sites of wildlife habitats and predict suitable future sites where wildlife would likely relocate to, dependent on the effects of climate change and based on a timeframe of scientifically backed temperature-increase estimates. Our findings show that Random Forest outperforms other competing models, with an accuracy of 0.897, and a sensitivity and specificity of 0.917 and 0.885, respectively, and has great potential in Species Distribution Modeling (SDM), which can provide useful insights into habitat predictions. Based on this model, our predictions show that sage-grouse habitats in Utah will continue to decrease over the coming years due to climate change, producing a highly fragmented habitat and causing a loss of close to 70% of their current habitat. Priority Areas of Conservation (PACs) and protected areas might be deemed insufficient to halt this habitat loss, and more effort should be put into maintaining connectivity between patches to ensure the movement and genetic diversity within the sage-grouse population. The underlying data-driven methodical approach of this study could be useful for environmentalists, researchers, decision-makers, and policymakers, among others.

Demography of the Cooperatively Breeding Splendid Fairy-Wren, Malurus-Splendens (Maluridae)

1993 ◽  
Vol 41 (5) ◽  
pp. 475 ◽  
Author(s):  
EM Russell ◽  
I Rowley
Keyword(s):  
Population Density ◽  
Sex Ratio ◽  
Breeding Season ◽  
Cooperative Breeding ◽  
Reproductive Effort ◽  
Austral Spring ◽  
Minor Variation ◽  
Proximate Cause ◽  
Female Survival ◽  
High Reproductive Effort

We studied the demography of the splendid fairy-wren, Malurus splendens, a group-territorial, cooperative-breeding passerine, near Perth, Western Australia, from 1973 to 1990. This period included 13 years of below-average rainfall, a number of minor wildfires and one that burnt 95% of the study area in January 1985. Annual survival of breeding males (mean = 70%) and females (mean = 59%) was higher during a period without fire. Survival of breeding females fell to less than 50% from 1987 to 1989, two years after the major fire. Survival of adults did not vary with age, but survival of juveniles was lower (mean=31%) and variable (range 11-59%), particularly among those produced in the first breeding season after the fire in 1985. Splendid fairy-wrens bred during the Austral spring, with minor variation in length of the breeding season depending on rainfall at the start and temperature at the end of the breeding season. Clutch size varied little, but females laid more clutches in years when predation or brood parasitism were high, particularly in the two years after the major fire. Females produced a mean of 2.9 fledglings each season (4.7 in the best year), but productivity was low for several years after the 1985 fire. Helpers attended 60% of all nests but overall had little effect on annual fledgling production. Experienced females were more productive than novices, both with and without helpers. High reproductive effort, indexed by days nesting and caring for fledglings, did not reduce a female's chance of survival to the next breeding season, and annual reproductive effort was not correlated with female survival. Differential dispersal and mortality produced variation in the adult sex ratio. During the fire-free period 1978-84, the numbers of non-breeding males and females increased, because of a lack of available territories rather than a lack of available partners. Variation in natality and survival caused large variations in population density but the density of breeders was more constant (C.V. = 24%) than than of helpers (C.V. = 57%). No decline in the population after the major fire of January 1985 was apparent until the 1988 breeding season; the number of groups declined from 1988 to 1990, some previously occupied territories became vacant and group size decreased. This delayed decline in population is attributed to decreased production of fledglings in the years after the fire and the gradual replacement of experienced breeding females by novices, which were less productive and suffered higher mortality. The major causes of demographic variation (brood parasites and fire) directly affected natality and juvenile survival; indirectly, population density, age structure, sex ratio and group composition were affected. Delayed dispersal, the proximate cause of cooperative breeding in splendid fairy-wrens, is favoured by this demographic environment. The widespread occurrence of similar demographic profiles may in part explain the high frequency of cooperative breeding in Australian birds.

Évolution du rapport des sexes de populations de Rumex acetosella le long d'une succession postculturale

1987 ◽  
Vol 65 (12) ◽  
pp. 2668-2675 ◽  
Author(s):  
Josep Escarré ◽  
Claudie Houssard ◽  
Jean Paul Briane
Keyword(s):  
Aboveground Biomass ◽  
Reproductive Effort ◽  
Vegetative Reproduction ◽  
Natural Populations ◽  
Energetic Cost ◽  
Allocation Pattern ◽  
Growing Seasons ◽  
Rumex Acetosella ◽  
High Reproductive Effort ◽  
Successional Stages

The sex ratios of natural populations of Rumex acetosella L. have been recorded during two growing seasons, along a successional gradient of abandoned agricultural fields of various ages (from 6 months to 15 years old), south of Paris. At the same time, male and female ramets have been collected to determine the resource allocation pattern of the different organs. We have observed that females of Rumex acetosella L. were more frequent than males at the younger stages, and that males predominated at the older ones. Concomitantly, there was a decrease in aboveground biomass and in the reproductive effort of the two sexes in the field, with increasing community maturity. The decrease in reproductive effort was confirmed, in controlled conditions, in the female genets only. Females always produced a higher reproductive effort and a higher aboveground biomass than males, which may explain why they were more abundant in the younger successional stages. Otherwise, our results show that sexual reproduction represented a high energetic cost which tended to consume root resources. Females, and mainly those of the younger stages which presented a high reproductive effort, may suffer more than males. The latter, which were more vigorous in vegetative reproduction and less affected by flower production than females, prevailed at older stages.

High reproductive effort is associated with decreasing mortality late in life in captive ruffed lemurs

2017 ◽  
Vol 79 (9) ◽  
pp. e22677 ◽  
Author(s):  
Morgane Tidière ◽  
Jean-François Lemaître ◽  
Guillaume Douay ◽  
Mylisa Whipple ◽  
Jean-Michel Gaillard
Keyword(s):  
Reproductive Effort ◽  
High Reproductive Effort

scholarly journals Effects of climatic variation and reproductive trade-offs vary by measure of reproductive effort in greater sage-grouse

Ecosphere ◽  
2014 ◽  
Vol 5 (12) ◽  
pp. art154 ◽  
Author(s):  
Danny Caudill ◽  
Michael R. Guttery ◽  
Brent Bibles ◽  
Terry A. Messmer ◽  
Gretchen Caudill ◽  
...  
Keyword(s):  
Reproductive Effort ◽  
Climatic Variation ◽  
Sage Grouse ◽  
Trade Offs

scholarly journals Seasonal Decline in Leukocyte Concentrations and Reproductive Output in Female Great Tits (Parus Major)

The Auk ◽  
2005 ◽  
Vol 122 (3) ◽  
pp. 829-834 ◽  
Author(s):  
Anna Dubiec ◽  
Magdalena Witek ◽  
Mariusz Cichoń
Keyword(s):  
Breeding Season ◽  
Reproductive Output ◽  
Reproductive Effort ◽  
Parus Major ◽  
Breeding Parameters ◽  
High Reproductive Effort ◽  
Leukocyte Counts ◽  
Seasonal Decline ◽  
The Relationship ◽  
Leukocyte Concentration

Abstract We studied the relationship between breeding parameters and leukocyte counts (number of cells in 1 mm3 of blood) in Great Tit (Parus major) females. To exclude potential effects on leukocyte concentration of high reproductive effort related to nestling provisioning, we collected blood samples from females at the end of their incubation period. Early-breeding females had greater blood counts of total leukocytes, lymphocytes, and heterophils than birds starting their clutches late in the season. Reproductive success, measured as the number of successfully fledged young, declined over the breeding season and showed no association with total leukocyte concentration. Number of leukocytes was not related to female condition measured as residuals from the regression of body weight on tarsus length. Moreover, the concentration of leukocytes did not predict the probability that a female would survive to the following breeding season. Disminución Estacional en las Concentraciones de Leucocitos y en el Rendimiento Reproductivo en Parus major

scholarly journals Nesting and Reproductive Activities of Greater Sage-Grouse in a Declining Northern Fringe Population

The Condor ◽  
2001 ◽  
Vol 103 (3) ◽  
pp. 537-543 ◽  
Author(s):  
Cameron L. Aldridge ◽  
R. Mark Brigham
Keyword(s):  
Reproductive Effort ◽  
Radio Telemetry ◽  
Population Decline ◽  
Centrocercus Urophasianus ◽  
Chick Survival ◽  
Sage Grouse ◽  
Brood Rearing ◽  
Northern Edge ◽  
Northern Fringe ◽  
Reproductive Activities

Abstract In Canada, Greater Sage-Grouse (Centrocercus urophasianus) are at the northern edge of their range, occurring only in southeastern Alberta and southwestern Saskatchewan. The population in Canada has declined by 66% to 92% over the last 30 years. We used radio-telemetry to follow 20 female Greater Sage-Grouse and monitor productivity in southeastern Alberta, and to assess habitat use at nesting and brood-rearing locations. All females attempted to nest. Mean clutch size (7.8 eggs per nest) was at the high end of the normal range for sage-grouse (typically 6.6–8.2). Nest success (46%) and breeding success (55%) were within the range found for more southerly populations (15% to 86% and 15% to 70%, respectively). Thirty-six percent of unsuccessful females attempted to renest. Fledging success was slightly lower than reported in other studies. Thus, reproductive effort does not appear to be related to the population decline. However, chick survival to ≥50 days of age (mean = 18%) was only about half of that estimated (35%) for a stable or slightly declining population, suggesting that chick survival may be the most important factor reducing overall reproductive success and contributing to the decline of Greater Sage-Grouse in Canada. Actividades de Anidación y Reproducción de Centrocercus urophasianus en una Población del Extremo Norte en Declive Resumen. En Canadá, Centrocercus urophasianus está en el extremo norte de su distribución, encontrándose sólo en el sureste de Alberta y el suroeste de Saskatchewan. La población de Canadá ha disminuido entre el 66% y 92% durante los últimos 30 años. Utilizamos radio-telemetría para seguir a 20 hembras de C. urophasianus y monitorear su productividad en el sureste de Alberta y para evaluar el uso de hábitat en sitios de anidación y de cría de los pichones. Todas las hembras intentaron anidar. El tamaño promedio de la nidada (7.8 huevos por nido) estuvo en el extremo superior del rango normal de C. urophasianus (típicamente 6.6–8.2). El éxito de anidación (46%) y de reproducción (55%) estuvieron dentro de los rangos encontrados en poblaciones de más al sur (15% a 86% y 15% a 70%, respectivamente). El treinta y seis por ciento de las hembras que no tuvieron éxito intentaron volver a anidar. El éxito en la crianza de polluelos hasta la etapa de volantones fue ligeramente menor que el reportado en otros estudios. Por lo tanto, el esfuerzo reproductivo no parece estar relacionado con el declive poblacional. Sin embargo, la supervivencia de los polluelos hasta 50 días de edad o más (promedio = 18%) fue sólo aproximadamente la mitad de lo que se ha estimado para una población estable o en ligero declive (35%), lo que sugiere que la supervivencia de los pichones podría ser el factor más importante reduciendo el éxito reproductivo en general y contribuyendo al declive de C. urophasianus en Canadá.

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