Population Biology of Marine Iguanas (Amblyrhynchus cristatus). II. Changes in Annual Survival Rates and the Effects of Size, Sex, Age and Fecundity in a Population Crash

10.2307/4879 ◽  
1990 ◽  
Vol 59 (2) ◽  
pp. 529 ◽  
Author(s):  
W. A. Laurie ◽  
D. Brown
Keyword(s):  
Population Biology ◽  
Survival Rates ◽  
Annual Survival ◽  
Amblyrhynchus Cristatus ◽  
Population Crash ◽  
Marine Iguanas

DNA metabarcoding reveals fine scale geographical differences of consumed algae in the Galápagos marine iguanas (Amblyrhynchus cristatus)

2021 ◽  
pp. 1-10
Author(s):  
Sten Anslan ◽  
Denisse Dalgo ◽  
Timm Reinhardt ◽  
Nicolás Peñafiel ◽  
Juan Guayasamin ◽  
...  
Keyword(s):  
Algal Species ◽  
Marine Macroalgae ◽  
Rbcl Gene ◽  
Ribulose Bisphosphate Carboxylase ◽  
Geographical Differences ◽  
Bisphosphate Carboxylase ◽  
Amblyrhynchus Cristatus ◽  
Dna Metabarcoding ◽  
Feeding Activities ◽  
Marine Iguanas

Abstract Galápagos marine iguanas are primarily associated with the marine environment and show special nutritional adaptations. They are the only lizards worldwide that forage on marine macroalgae. Until now, consumed algae have been identified by direct observations during their feeding activities and microscopic identification in faeces samples. In this study, we use a novel DNA metabarcoding approach to identify consumed algal species from the faeces of marine iguanas. We developed primers for the ribulose-bisphosphate carboxylase (rbcL) gene and applied a metabarcoding approach to 25 individual faeces samples collected in four representative sites of two subspecies (Amblyrhynchus cristatus mertensi and A. c. godzilla), found in the San Cristóbal Island. We detected 18 consistently occurring macroalgal operational taxonomic units (OTUs). Most of the OTUs were assigned to Rhodophyta (red algae) and only one OTU to Chlorophyta (green algae). Despite the number of consumed algal species did not differ between two subspecies (OTU richness; P = 0.383), diet overlap level between A. c. mertensi and A. c. godzilla was low (Schoener index = 0.345), suggesting that both subspecies consumed different algal species in their natural environment. Further studies are needed to understand whether the difference of consumed algae reflects disparities in the abundance of algal species between sites, or whether iguanas of the two genetically differentiated subspecies prefer distinct algal 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.

Demography of the San Francisco Gartersnake in Coastal San Mateo County, California

2011 ◽  
Vol 2 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Brian J. Halstead ◽  
Glenn D. Wylie ◽  
Melissa Amarello ◽  
Jeffrey J. Smith ◽  
Michelle E. Thompson ◽  
...  
Keyword(s):  
San Francisco ◽  
Survival Rates ◽  
Thamnophis Sirtalis ◽  
Annual Survival ◽  
Coastal Prairie ◽  
Probability Of Survival ◽  
Annual Probability ◽  
The Status ◽  
San Mateo County

Abstract The San Francisco gartersnake Thamnophis sirtalis tetrataenia has been federally listed as endangered since 1967, but little demographic information exists for this species. We examined the demography of a San Francisco gartersnake population on approximately 213 ha of California coastal prairie in San Mateo County, California, from 2007 to 2010. The best-supported mark–recapture model indicated annual variation in daily capture probabilities and annual survival rates. Abundance increased throughout the study period, with a mean total population from 2008 to 2010 of 443 (95% CI  =  313–646) individuals. Annual survival was slightly greater than that of most other gartersnakes, with an annual probability of survival of 0.78 (0.55–0.95) in 2008–2009 and 0.75 (0.49–0.93) in 2009–2010. Mean annual per capita recruitment rates were 0.73 (0.02–2.50) in 2008–2009 and 0.47 (0.02–1.42) in 2009–2010. From 2008 to 2010, the probability of an increase in abundance at this site was 0.873, with an estimated increase of 115 (−82 to 326) individuals. The estimated population growth rate in 2008–2009 was 1.52 (0.73–3.29) and in 2009–2010 was 1.21 (0.70–2.17). Although this population is probably stable or increasing in the short term, long-term studies of the status of the San Francisco gartersnake at other sites are required to estimate population trends and to elucidate mechanisms that promote the recovery of this charismatic member of our native herpetofauna.

Improving Estimates of Annual Survival Rates for Medial Unicompartmental Knee Arthroplasty, a Meta-Analysis

2019 ◽  
Vol 34 (7) ◽  
pp. 1538-1545 ◽  
Author(s):  
Braiden M. Heaps ◽  
Jason L. Blevins ◽  
Yu-Fen Chiu ◽  
Joseph F. Konopka ◽  
Shaun P. Patel ◽  
...  
Keyword(s):  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Meta Analysis ◽  
Survival Rates ◽  
Annual Survival ◽  
Unicompartmental Knee ◽  
Medial Unicompartmental Knee Arthroplasty

Life history and demography of an uncooperative Australian passerine, the brown thornbill

1999 ◽  
Vol 47 (6) ◽  
pp. 633 ◽  
Author(s):  
David J. Green ◽  
Andrew Cockburn
Keyword(s):  
Phylogenetic Analysis ◽  
Life History ◽  
Breeding Season ◽  
Cooperative Breeding ◽  
Mating Systems ◽  
Survival Rates ◽  
Reproductive Conflict ◽  
Annual Survival ◽  
Shed Light ◽  
C 63

The genus Acanthiza may be important in understanding the evolution of avian mating systems because while brown thornbills, Acanthiza pusilla, are thought to breed only in pairs, a recent phylogenetic analysis suggests that cooperative breeding is the ancestral trait within this genus. We provide a detailed account of the breeding biology of the brown thornbill, confirm that they breed exclusively in pairs, and compare their population demography with what is known for other members of the Pardalotidae. We found that brown thornbills produced small clutches (3 eggs) with a two-day laying interval, had a long incubation period (declining from 19 to 16 days through the season), and had a long breeding season (4.0 months) that allowed females to occasionally raise two successful broods. Brown thornbills, in our study, produced an average of 1.57 fledglings per pair and had relatively high annual survival rates (c. 63%). We found no evidence to suggest that the evolution of pair-breeding within the Pardalotidae is associated with a reduction in annual survival rates, a short breeding season with reduced productivity, or high levels of predation post-fledging. Since there also appear to be no ecological correlates with mating system in the Pardalotidae we suggest that examination of reproductive conflict between parents and young may shed light on the evolution of pairbreeding in this family.

scholarly journals Climate anomalies affect annual survival rates of swifts wintering in sub‐Saharan Africa

2020 ◽  
Vol 10 (14) ◽  
pp. 7916-7928 ◽  
Author(s):  
Giovanni Boano ◽  
Irene Pellegrino ◽  
Mauro Ferri ◽  
Marco Cucco ◽  
Fausto Minelli ◽  
...  
Keyword(s):  
Survival Rates ◽  
Sub Saharan Africa ◽  
Annual Survival ◽  
Climate Anomalies ◽  
Sub Saharan

scholarly journals Hibernation is associated with increased survival and the evolution of slow life histories among mammals

2011 ◽  
Vol 278 (1723) ◽  
pp. 3355-3363 ◽  
Author(s):  
Christopher Turbill ◽  
Claudia Bieber ◽  
Thomas Ruf
Keyword(s):  
Life Histories ◽  
Survival Rates ◽  
Diverse Range ◽  
Annual Survival ◽  
Active Season ◽  
Evolutionary Theories ◽  
Generation Times ◽  
Evolution Of Life ◽  
Reproductive Rates ◽  
Similar Survival

Survival probability is predicted to underlie the evolution of life histories along a slow–fast continuum. Hibernation allows a diverse range of small mammals to exhibit seasonal dormancy, which might increase survival and consequently be associated with relatively slow life histories. We used phylogenetically informed GLS models to test for an effect of hibernation on seasonal and annual survival, and on key attributes of life histories among mammals. Monthly survival was in most cases higher during hibernation compared with the active season, probably because inactivity minimizes predation. Hibernators also have approximately 15 per cent higher annual survival than similar sized non-hibernating species. As predicted, we found an effect of hibernation on the relationships between life history attributes and body mass: small hibernating mammals generally have longer maximum life spans (50% greater for a 50 g species), reproduce at slower rates, mature at older ages and have longer generation times compared with similar-sized non-hibernators. In accordance with evolutionary theories, however, hibernating species do not have longer life spans than non-hibernators with similar survival rates, nor do they have lower reproductive rates than non-hibernators with similar maximum life spans. Thus, our combined results suggest that (i) hibernation is associated with high rates of overwinter and annual survival, and (ii) an increase in survival in hibernating species is linked with the coevolution of traits indicative of relatively slow life histories.

Sign in / Sign up

Export Citation Format

Share Document