scholarly journals Annual Survivorship of the Sedentary Rufous-Crowned Sparrow (Aimophila Ruficeps): No Detectable Effects of Edge or Rainfall in Southern California

The Auk ◽  
2004 ◽  
Vol 121 (3) ◽  
pp. 904-916
Author(s):  
Scott A. Morrison ◽  
Douglas T. Bolger ◽  
T. Scott Sillett
Keyword(s):  
Southern California ◽  
Survival Rates ◽  
San Diego County ◽  
Adult Survival ◽  
Survivorship Analysis ◽  
Annual Survival ◽  
Survival Probabilities ◽  
Nonbreeding Season ◽  
Aimophila Ruficeps ◽  
Habitat Edge

Abstract The Rufous-crowned Sparrow (Aimophila ruficeps) is a nonmigratory passerine that displays an area-sensitive distribution pattern of abundance in fragmented coastal sagescrub habitat of southern California. To determine if habitat fragmentation negatively affected adult survival, we used Cormack-Jolly-Seber models to compare annual survival probabilities of adult sparrows breeding in habitat adjacent to urban-developed edges to those of birds breeding in the interior of large habitat expanses in San Diego County, 1997–2000. During that period, an El Niño event brought heavy rainfall to the study area, and a La Niña event brought drought. Annual survival probabilities were relatively high for a small passerine (females: 0.69 ± 0.05 SE; males: 0.74 ± 0.04 SE) but, given our data, did not differ between habitat types or with rainfall. Annual resighting probabilities for the birds were strongly associated with variation in rainfall, being high in the wet year and low in the dry year. Mate- and site-fidelity were apparently high, and surveys during the nonbreeding season documented that the sparrows stayed paired and on territories year-round. We hypothesize that the high apparent survivorship of this species is related to its nonmigratory habit and its tendency to curtail reproductive effort during periods of food scarcity. Although our survivorship analysis suggests that the urban-wildland interface does not adversely affect survival of territorial Rufous-crowned Sparrows, our power to detect an effect of habitat edge on survival was low. Thus, we urge caution in concluding that edge effects do not have an ecologically important influence on survival rates in this species.

Survival of red-capped robins (Petroica goodenovii) in woodland remnants of central western New South Wales, Australia

2001 ◽  
Vol 28 (6) ◽  
pp. 565 ◽  
Author(s):  
Richard E. Major ◽  
Greg Gowing
Keyword(s):  
Survival Rates ◽  
Relative Survival ◽  
Adult Mortality ◽  
Annual Survival ◽  
Survival Probabilities ◽  
South Wales ◽  
Winter Half ◽  
Linear Habitat ◽  
Significant Difference ◽  
Summer Half

To determine relative survival rates of small birds occupying small, linear strips of woodland compared with large patches of woodland, marked populations of red-capped robins were monitored over a two-year period. In total, 196 male robins were banded with unique colour combinations in 10 woodland remnants and censused by song playback at half-yearly intervals. The Cormack–Jolly–Seber method was used to calculate half-yearly survival probabilities for birds in the two habitat configurations and the strongest model included separate survival parameters for summer (36.2% 5.1) and autumn (88.9% 13.5) half-years, but a constant recapture probability (50.5% 7.2). The inclusion of separate parameters for the large and linear habitat configurations reduced the strength of the model, indicating that there was no significant difference between the survival rates of birds occupying small, linear strips of woodland and birds occupying large patches of woodland. The mean annual survival, determined by multiplying the half-yearly survival probabilities, was 32%, which is low, compared with the annual survival of other Petroica robins. Although no banded birds were located away from the banding site, we suspect that much of the ‘mortality’ represented emigration during the summer half-year. Under this scenario a better estimate of annual survival (79%) might be achieved by extrapolation of survival over the winter half-year. This study provides no data to support the contention that adult mortality is higher in small, linear strips of habitat, although further data on the fate of birds that disappear from remnants is required before this is conclusive. In addition, to detect a 20% difference in survival using similar methods to the present study, with their accompanying sources of variation, at least 10 times the number of birds would need to be monitored. This might most effectively be done as a co-operative banding project.

scholarly journals Population dynamics of the endangered mountain ecotype of woodland caribou (Rangifer tarandus caribou) in British Columbia, Canada

2020 ◽  
Author(s):  
Heiko Wittmer ◽  
BN McLellan ◽  
DR Seip ◽  
JA Young ◽  
TA Kinley ◽  
...  
Keyword(s):  
British Columbia ◽  
Population Dynamics ◽  
Rangifer Tarandus ◽  
Population Decline ◽  
Survival Rates ◽  
Adult Survival ◽  
Rangifer Tarandus Caribou ◽  
Vital Rates ◽  
Woodland Caribou ◽  
Annual Survival

We used census results and radiotelemetry locations of >380 collared individuals sampled over the entire distribution of the endangered mountain ecotype of woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) in British Columbia, Canada, to delineate population structure and document the size and trend of the identified populations. We also describe the spatial pattern of decline and the causes and timing of adult mortality and provide estimates of vital rates necessary to develop a population viability analysis. Our results indicate that the abundance of mountain caribou in British Columbia is declining. We found adult female annual survival rates below annual survival rates commonly reported for large ungulates. The major proximate cause of population decline appears to be predation on adult caribou. Spatial patterns of population dynamics revealed a continuous range contraction and an increasing fragmentation of mountain caribou into smaller, isolated subpopulations. The population fragmentation process predominantly occurs at the outer boundaries of the current distribution. Our results indicate that recovery strategies for mountain caribou should be directed at factors contributing to the fragmentation and isolation of mountain caribou populations as well as management strategies aimed at increasing adult survival. © 2005 NRC Canada.

scholarly journals The fast–slow continuum of longevity among yellow-bellied toad populations (Bombina variegata): intrinsic and extrinsic drivers of variation

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e8233 ◽  
Author(s):  
Alena Marcella Hantzschmann ◽  
Birgit Gollmann ◽  
Günter Gollmann ◽  
Ulrich Sinsch
Keyword(s):  
Survival Rates ◽  
Somatic Growth ◽  
Environmental Stochasticity ◽  
Adult Survival ◽  
Life History Trait ◽  
Extrinsic Factors ◽  
Annual Survival ◽  
Continental Scale ◽  
Bombina Variegata ◽  
Pathogen Prevalence

Yellow-bellied toad populations (Bombina variegata) show a wide fast–slow continuum of the life-history trait longevity ranging from 5 to 23 years. We investigated populations in Germany (n = 8) and Austria (n = 1) to determine their position within the continuum of longevity and the potential drivers of adult survival at the local and the continental scale. Intrinsic and extrinsic factors considered were local weather, nutritional state, allocation of ingested energy to somatic growth, pathogen prevalence, and geographical clines (latitude, altitude, and longitude). Capture-mark-recapture (CMR) monitoring and direct age assessment by skeletochronology allowed for reliable estimates of longevity and adult survival. Raw and corrected recapture rates as well as a probabilistic estimate of the lifespan of the eldest 1% adults of a cohort (CMR data) were used as surrogates for adult survival and thus longevity in a population. Additionally, survival rates were calculated from static life tables based on the age structure (skeletochronological data) of eight populations. Populations in Germany were short-lived with a maximum lifespan of annual cohorts varying from 5 to 8 years, whereas the population in Austria was long-lived with a cohort longevity of 13 to 23 years. We provide evidence that annual survival rates and longevity differ among years and between short- and long-lived populations, but there was no decrease of survival in older toads (i.e. absence of senescence). Variation of weather among years accounted for 90.7% of variance in annual survival rates of short-lived populations, whereas the sources of variation in the long-lived population remained unidentified. At the continental scale, longevity variation among B. variegata populations studied so far did not correspond to geographical clines or climate variation. Therefore, we propose that a population’s position within the fast–slow continuum integrates the response to local environmental stochasticity (extrinsic source of variation) and the efficiency of chemical antipredator protection determining the magnitude of longevity (intrinsic source of variation).

Population dynamics of the black-cheeked gnateater (Conopophaga melanops, Conopophagidae) in southern Brazil

2009 ◽  
Vol 25 (6) ◽  
pp. 605-613 ◽  
Author(s):  
André Magnani Xavier de Lima ◽  
James Joseph Roper
Keyword(s):  
Population Dynamics ◽  
Population Growth ◽  
Breeding Season ◽  
Survival Rates ◽  
Territory Size ◽  
Adult Survival ◽  
Southern Brazil ◽  
Annual Survival ◽  
Socially Monogamous ◽  
Population Structure And Dynamics

Abstract:Population structure and dynamics of the black-cheeked gnateater (Conopophaga melanops) were studied at Salto Morato Nature Reserve, in Paraná, southern Brazil, from October 2006 to September 2007. Territory size and population density, breeding season (timing and length), reproductive success and annual survival rates were estimated from sightings of 18 marked adult birds and the success of 18 nesting attempts. The black-cheeked gnateater is socially monogamous and territorial, with a breeding-season length of approximately 3 mo beginning in early October. Predation caused most nest failures, nest survival was 0.96 d−1and apparent annual nesting success was 22%, resulting in annual productivity of 0.36 individuals per adult. Apparent adult annual survival was ~0.44 y−1. Seventy-five per cent of fledglings survived at least 2 mo after fledging. Two methods of estimating population growth rate suggest very different rates: r = −0.04 (~ stable), or λ varies between 0.475–0.616 (declining). Yet, low apparent adult survival suggests that territories are not permanent, perhaps abandoned after nest failure. We find that by estimating population growth, even in short-term studies, testable hypotheses can be generated that will allow better understanding of population dynamics.

scholarly journals Reef manta ray life history and demography: is it really all about survival?

2016 ◽  
Author(s):  
Isabel M Smallegange ◽  
Isabelle BC van der Ouderaa ◽  
Yara Tibiriçá
Keyword(s):  
Growth Rate ◽  
Survival Rate ◽  
Population Growth ◽  
Population Growth Rate ◽  
Survival Rates ◽  
Adult Survival ◽  
Lifetime Reproductive Success ◽  
Annual Survival ◽  
Manta Ray ◽  
Reef Manta Ray

Background. The trade in gill plates of devil and manta rays has increased greatly over the last two decades. The resulting increased mortality, in addition to mortality caused by by-catch, means that many ray populations are declining in size. The aim of this study was to ascertain the main demographic drivers of population change in reef manta rays (Manta alfredi) to increase our understanding of their demography and hence provide insight into potential conservation measures. Methods. We developed a population projection model for reef manta rays and used published life history data to parameterise the model and also used these data as points of reference to compare our model output to. Because little is known about yearling and juvenile survival of reef manta rays, we conducted our analyses across a range of plausible survival rate values of yearlings, juveniles, and also adults. Results. The model accurately captured observed patterns of variation in population growth rate, lifetime reproductive success and cohort generation time for different reef manta ray populations around the world. Varying the survival rates of the different life stages revealed that increasing adult annual survival rate always positively and additively affected population growth rate, lifetime reproductive success and cohort generation time. Variation in yearling and juvenile annual survival rate, however, had different and varying effects on the latter three population descriptors, highlighting the importance of obtaining accurate estimates of these survival rates from natural populations. Our elasticity analysis revealed that for both declining and stable populations, the population growth rate is most sensitive to changes in either juvenile or adult survival rate, depending on yearling and adult annual survival rate values. Discussion. Many reef manta ray populations are declining, resulting in local extinction unless effective conservation measures are taken. Based on our detailed demographic analysis, we suggest that reef manta ray conservation would particularly benefit from focusing on increasing juvenile and adult survival.

scholarly journals Metabolic rate is negatively linked to adult survival but does not explain latitudinal differences in songbirds

2019 ◽  
Author(s):  
Andy J. Boyce ◽  
James C. Mouton ◽  
Penn Lloyd ◽  
Blair O. Wolf ◽  
Thomas E. Martin
Keyword(s):  
Metabolic Rate ◽  
Survival Rates ◽  
Latitudinal Variation ◽  
Adult Survival ◽  
Metabolic Rates ◽  
Direct Effects ◽  
Physiological Mechanisms ◽  
Annual Survival ◽  
Lower Survival

ABSTRACTSurvival rates vary dramatically among species and predictably across latitudes, but causes of this variation are unclear. The rate of living hypothesis posits that physiological damage from metabolism causes species with faster metabolic rates to exhibit lower survival rates. However, whether increased survival commonly observed in tropical and south temperate latitudes is associated with slower metabolic rate remains unclear. We compared metabolic rates and annual survival rates across 46 species that we measured, and 147 species from literature data across northern, southern, and tropical latitudes. High metabolic rates were associated with lower survival but latitude had substantial direct effects on survival independent of metabolism. The inability of metabolic rate to explain latitudinal variation in survival suggests 1) that species may evolve physiological mechanisms that mitigate physiological damage from cellular metabolism, and 2) a larger role of extrinsic environmental, rather than intrinsic metabolic, causes of latitudinal differences in mortality.

Robustness of adult female survival maintains a high-density sika deer (Cervus nippon) population following the initial irruption

2018 ◽  
Vol 45 (2) ◽  
pp. 143 ◽  
Author(s):  
M. Ueno ◽  
H. Iijima ◽  
K. Takeshita ◽  
H. Takahashi ◽  
T. Yoshida ◽  
...  
Keyword(s):  
Sika Deer ◽  
Survival Rates ◽  
Cervus Nippon ◽  
High Density ◽  
Food Sources ◽  
Adult Survival ◽  
Density Level ◽  
Annual Survival ◽  
Deer Population ◽  
Winter Severity

Context Irruption of large herbivore populations is characterised by three distinct phases: (1) an exponential increase in population to a peak abundance; (2) a population crash; and (3) a second increase to another population peak, typically lower than the first peak of abundance. However, there has been little study of age- and sex-specific factors that affect the post-initial irruption interactions with food sources. Aims We aimed to investigate annual survival rates of sika deer (Cervus nippon Temminck, 1838) in the sequent irruption of a population on Nakanoshima Island, Lake Toya, Japan, with a chronically high density during the period 2002–12. Methods Survival monitoring data were obtained for 219 individuals (93 males and 126 females) using radio-collars. Annual survival was quantified, and related factors, i.e. deer abundance and winter severity, were determined by model selection using Akaike information criterion values. Key Results The results showed that annual survival rates across sexes and age classes (fawn, yearling, prime-aged, old) decreased with increasing population density, snow depth and winter precipitation. Winter severity had a greater effect on adult survival than density regulation. Nevertheless, female adult survival was maintained at a high level, with a mean of 0.84 (95% CI: 0.80–0.88). Key conclusions Robust survival rates for adult females might contribute to the maintenance of a high-density sika deer population in the post-initial irruption. Implications We suggest that in the absence of predation and hunting, sika deer population is not able to self-regulate to the density level that avoids an irreversible impact on plants.

scholarly journals Population dynamics of the endangered mountain ecotype of woodland caribou (Rangifer tarandus caribou) in British Columbia, Canada

2020 ◽  
Author(s):  
Heiko Wittmer ◽  
BN McLellan ◽  
DR Seip ◽  
JA Young ◽  
TA Kinley ◽  
...  
Keyword(s):  
British Columbia ◽  
Population Dynamics ◽  
Rangifer Tarandus ◽  
Population Decline ◽  
Survival Rates ◽  
Adult Survival ◽  
Rangifer Tarandus Caribou ◽  
Vital Rates ◽  
Woodland Caribou ◽  
Annual Survival

We used census results and radiotelemetry locations of >380 collared individuals sampled over the entire distribution of the endangered mountain ecotype of woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) in British Columbia, Canada, to delineate population structure and document the size and trend of the identified populations. We also describe the spatial pattern of decline and the causes and timing of adult mortality and provide estimates of vital rates necessary to develop a population viability analysis. Our results indicate that the abundance of mountain caribou in British Columbia is declining. We found adult female annual survival rates below annual survival rates commonly reported for large ungulates. The major proximate cause of population decline appears to be predation on adult caribou. Spatial patterns of population dynamics revealed a continuous range contraction and an increasing fragmentation of mountain caribou into smaller, isolated subpopulations. The population fragmentation process predominantly occurs at the outer boundaries of the current distribution. Our results indicate that recovery strategies for mountain caribou should be directed at factors contributing to the fragmentation and isolation of mountain caribou populations as well as management strategies aimed at increasing adult survival. © 2005 NRC Canada.

scholarly journals Reef manta ray life history and demography: is it really all about survival?

2016 ◽  
Author(s):  
Isabel M Smallegange ◽  
Isabelle BC van der Ouderaa ◽  
Yara Tibiriçá
Keyword(s):  
Growth Rate ◽  
Survival Rate ◽  
Population Growth ◽  
Population Growth Rate ◽  
Survival Rates ◽  
Adult Survival ◽  
Lifetime Reproductive Success ◽  
Annual Survival ◽  
Manta Ray ◽  
Reef Manta Ray

Background. The trade in gill plates of devil and manta rays has increased greatly over the last two decades. The resulting increased mortality, in addition to mortality caused by by-catch, means that many ray populations are declining in size. The aim of this study was to ascertain the main demographic drivers of population change in reef manta rays (Manta alfredi) to increase our understanding of their demography and hence provide insight into potential conservation measures. Methods. We developed a population projection model for reef manta rays and used published life history data to parameterise the model and also used these data as points of reference to compare our model output to. Because little is known about yearling and juvenile survival of reef manta rays, we conducted our analyses across a range of plausible survival rate values of yearlings, juveniles, and also adults. Results. The model accurately captured observed patterns of variation in population growth rate, lifetime reproductive success and cohort generation time for different reef manta ray populations around the world. Varying the survival rates of the different life stages revealed that increasing adult annual survival rate always positively and additively affected population growth rate, lifetime reproductive success and cohort generation time. Variation in yearling and juvenile annual survival rate, however, had different and varying effects on the latter three population descriptors, highlighting the importance of obtaining accurate estimates of these survival rates from natural populations. Our elasticity analysis revealed that for both declining and stable populations, the population growth rate is most sensitive to changes in either juvenile or adult survival rate, depending on yearling and adult annual survival rate values. Discussion. Many reef manta ray populations are declining, resulting in local extinction unless effective conservation measures are taken. Based on our detailed demographic analysis, we suggest that reef manta ray conservation would particularly benefit from focusing on increasing juvenile and adult survival.

scholarly journals Population dynamics of the endangered mountain ecotype of woodland caribou (Rangifer tarandus caribou) in British Columbia, Canada

2005 ◽  
Vol 83 (3) ◽  
pp. 407-418 ◽  
Author(s):  
Heiko U Wittmer ◽  
Bruce N McLellan ◽  
Dale R Seip ◽  
James A Young ◽  
Trevor A Kinley ◽  
...  
Keyword(s):  
British Columbia ◽  
Population Dynamics ◽  
Rangifer Tarandus ◽  
Population Decline ◽  
Survival Rates ◽  
Adult Survival ◽  
Rangifer Tarandus Caribou ◽  
Vital Rates ◽  
Woodland Caribou ◽  
Annual Survival

We used census results and radiotelemetry locations of >380 collared individuals sampled over the entire distribution of the endangered mountain ecotype of woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) in British Columbia, Canada, to delineate population structure and document the size and trend of the identified populations. We also describe the spatial pattern of decline and the causes and timing of adult mortality and provide estimates of vital rates necessary to develop a population viability analysis. Our results indicate that the abundance of mountain caribou in British Columbia is declining. We found adult female annual survival rates below annual survival rates commonly reported for large ungulates. The major proximate cause of population decline appears to be predation on adult caribou. Spatial patterns of population dynamics revealed a continuous range contraction and an increasing fragmentation of mountain caribou into smaller, isolated subpopulations. The population fragmentation process predominantly occurs at the outer boundaries of the current distribution. Our results indicate that recovery strategies for mountain caribou should be directed at factors contributing to the fragmentation and isolation of mountain caribou populations as well as management strategies aimed at increasing adult survival.

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