Influence of the Mating System of the Eurasian Dipper on Sex-Specific Local Survival Rates

AbstractTo estimate annual apparent local survival, we collected capture–resighting data on 256 individually marked male Western Sandpipers (Calidris mauri) wintering at Estero de Punta Banda, Mexico, between 1994–1997. A hierarchical modeling approach was used to address the effect of age class and year on survivorship rates. The best-fit model included a constant apparent survival probability (ϕ = 0.489; 95% CI = 0.410–0.569), but several models fit nearly as well, and averaging among the top five, to account for model uncertainty, suggested that adults had somewhat higher values than juveniles (ϕ = 0.490 ± 0.051 vs. 0.450 ± 0.067). Detection probability was substantially higher for adults than for juveniles (p = 0.741 vs. p = 0.537). Those apparent survival estimates are low compared with those from other studies of Western Sandpipers at breeding and other nonbreeding locations, and substantially lower than the true survivorship rates expected for small sandpipers in general. We interpret these results as indicating that this site is of below average quality for nonbreeding male Western Sandpipers.

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Reproduction and survival of rodents in crop fields: the effects of rainfall, crop stage and stone-bund density

Wildlife Research ◽

10.1071/wr14121 ◽

2015 ◽

Vol 42 (2) ◽

pp. 158 ◽

Cited By ~ 5

Author(s):

Yonas Meheretu ◽

Kiros Welegerima ◽

Vincent Sluydts ◽

Hans Bauer ◽

Kindeya Gebrehiwot ◽

...

Keyword(s):

Survival Rates ◽

Development Stage ◽

Rodent Species ◽

Minor Role ◽

Pest Species ◽

Wet Season ◽

Proactive Management ◽

Local Survival ◽

Cropping Seasons ◽

A Minor

Context Reproduction and survival are two of the most important demographic factors that play a major role in changing population abundances of pest species over time and space, solid understanding of which is a useful input to forecast future population changes for proactive management. Aims We investigated the effects of rainfall, crop-development stage and density of stone bunds on reproductive patterns, and the effects of stone-bund density and sex on survival probabilities of two widespread rodent species (Mastomys awashensis and Arvicanthis dembeensis) in Ethiopian highlands. Methods Rodent population dynamics were monitored from April 2007 to February 2011, using capture–mark–recapture (CMR) technique in four 60 × 60 m permanent square grids for four consecutive cropping seasons. Two of the grids represented fields with low stone-bund density (LSBD, ~15 m apart) and the other two represented fields with high stone-bund density (HSBD, ~10 m apart). Key results Reproduction was seasonal, commencing during the wet season following the rain and continuing through the early dry season. We found an increase in the abundance of reproductively active female individuals of both species towards the milky and fruiting crop stages and around harvest period. We found no strong difference in survival probability between the two rodent species with variation in stone-bund density and sex. Conclusion Stone bunds play a minor role in the reproduction and survival of the rodent species at the observed abundances. Implications In terms of pest management, the high local survival rates estimated for both rodent species matter more than survival differences owing to variations in stone-bund density and sex.

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Ecological correlates of mate fidelity in two Arctic-breeding sandpipers

Canadian Journal of Zoology ◽

10.1139/z00-146 ◽

2000 ◽

Vol 78 (11) ◽

pp. 1948-1958 ◽

Cited By ~ 26

Author(s):

Brett K Sandercock ◽

David B Lank ◽

Richard B Lanctot ◽

Bart Kempenaers ◽

Fred Cooke

Keyword(s):

Survival Rates ◽

Interspecific Variation ◽

Breeding Dispersal ◽

Mate Fidelity ◽

Interspecific Differences ◽

Local Survival ◽

Mate Change ◽

Western Sandpipers ◽

Interspecific Comparisons ◽

Semipalmated Sandpipers

Monogamous birds exhibit considerable interspecific variation in rates of mate fidelity between years, but the reasons for this variation are still poorly understood. In a 4-year study carried out in western Alaska, mate-fidelity rates in Semipalmated Sandpipers (Calidris pusilla; mate fidelity was 47% among pairs where at least one mate returned and 94% among pairs where both mates returned) were substantially higher than in Western Sandpipers (Calidris mauri; 25 and 67%, respectively), despite the similar breeding biology of these sibling species. Divorce was not a response to nesting failure in Western Sandpipers, and mate change had no effect on the reproductive performance of either species. Nor were mate-fidelity rates related to differential rates of breeding dispersal, because the species did not differ in site fidelity. Reunited pairs and males that changed mates showed strong site tenacity, while females that changed mates moved farther. Differences in local survival rates or habitat are also unlikely to explain mate fidelity, since the two species did not differ in local survival rates, ϕ (Western Sandpipers: ϕ hat = 0.57 ± 0.05 (mean ± SE), Semipalmated Sandpipers: ϕ hat = 0.66 ± 0.06), and they bred in the same area, sometimes using the same nest cups. Although we were able to reject the above explanations, it was not possible to determine whether mate retention was lower in Western Sandpipers than in Semipalmated Sandpipers because of interspecific differences in mating tactics, time constraints imposed by migration distance, or a combination of these factors. Western Sandpipers exhibited greater sexual size dimorphism, but also migrated for shorter distances and tended to nest earlier and more asynchronously than Semipalmated Sandpipers. Finally, we show that conventional methods underestimate divorce rates, and interspecific comparisons may be biased if breeding-dispersal and recapture rates are not considered.

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Toxin constraint explains diet choice, survival and population dynamics in a molluscivore shorebird

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2013.0861 ◽

2013 ◽

Vol 280 (1763) ◽

pp. 20130861 ◽

Cited By ~ 24

Author(s):

Jan A. van Gils ◽

Matthijs van der Geest ◽

Jutta Leyrer ◽

Thomas Oudman ◽

Tamar Lok ◽

...

Keyword(s):

Survival Rates ◽

The Other ◽

Energy Requirements ◽

Diet Choice ◽

Optimal Diet ◽

Trade Off ◽

Local Survival ◽

Toxic Food ◽

Red Knot ◽

Diet Model

Recent insights suggest that predators should include (mildly) toxic prey when non-toxic food is scarce. However, the assumption that toxic prey is energetically as profitable as non-toxic prey misses the possibility that non-toxic prey have other ways to avoid being eaten, such as the formation of an indigestible armature. In that case, predators face a trade-off between avoiding toxins and minimizing indigestible ballast intake. Here, we report on the trophic interactions between a shorebird (red knot, Calidris canutus canutus ) and its two main bivalve prey, one being mildly toxic but easily digestible, and the other being non-toxic but harder to digest. A novel toxin-based optimal diet model is developed and tested against an existing one that ignores toxin constraints on the basis of data on prey abundance, diet choice, local survival and numbers of red knots at Banc d'Arguin (Mauritania) over 8 years. Observed diet and annual survival rates closely fit the predictions of the toxin-based model, with survival and population size being highest in years when the non-toxic prey is abundant. In the 6 of 8 years when the non-toxic prey is not abundant enough to satisfy the energy requirements, red knots must rely on the toxic alternative.

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Evidence of population resistance to extreme low flows in a fluvial-dependent fish species

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2015-0173 ◽

2015 ◽

Vol 72 (11) ◽

pp. 1776-1787 ◽

Cited By ~ 8

Author(s):

Rachel A. Katz ◽

Mary C. Freeman

Keyword(s):

Fish Species ◽

Survival Rates ◽

Low Flow ◽

Small Fish ◽

Severe Drought ◽

High Survival ◽

Opposite Pattern ◽

Flow Variability ◽

Low Flows ◽

Local Survival

Extreme low streamflows are natural disturbances to aquatic populations. Species in naturally intermittent streams display adaptations that enhance persistence during extreme events; however, the fate of populations in perennial streams during unprecedented low-flow periods is not well-understood. Biota requiring swift-flowing habitats may be especially vulnerable to flow reductions. We estimated the abundance and local survival of a native fluvial-dependent fish species (Etheostoma inscriptum) across 5 years encompassing historic low flows in a sixth-order southeastern USA perennial river. Based on capture–mark–recapture data, the study shoal may have acted as a refuge during severe drought, with increased young-of-the-year (YOY) recruitment and occasionally high adult immigration. Contrary to expectations, summer and autumn survival rates (30 days) were not strongly depressed during low-flow periods, despite 25%–80% reductions in monthly discharge. Instead, YOY survival increased with lower minimum discharge and in response to small rain events that increased low-flow variability. Age-1+ fish showed the opposite pattern, with survival decreasing in response to increasing low-flow variability. Results from this population dynamics study of a small fish in a perennial river suggest that fluvial-dependent species can be resistant to extreme flow reductions through enhanced YOY recruitment and high survival.

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Persistent organic pollution in a high-Arctic top predator: sex-dependent thresholds in adult survival

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2013.1483 ◽

2013 ◽

Vol 280 (1769) ◽

pp. 20131483 ◽

Cited By ~ 25

Author(s):

Kjell Einar Erikstad ◽

Hanno Sandvik ◽

Tone Kristin Reiertsen ◽

Jan Ove Bustnes ◽

Hallvard Strøm

Keyword(s):

Polychlorinated Biphenyl ◽

Survival Rates ◽

Organic Pollution ◽

High Arctic ◽

Adult Survival ◽

Breeding Populations ◽

Local Survival ◽

Negative Effect ◽

Capture Recapture ◽

Analysis Survival

In long-lived species, any negative effect of pollution on adult survival may pose serious hazards to breeding populations. In this study, we measured concentrations of various organochlorines (OCs) (polychlorinated biphenyl and OC pesticides) in the blood of a large number of adult glaucous gulls ( Larus hyperboreus ) breeding on Bjørnøya (Bear Island) in the Norwegian Arctic, and modelled their local survival using capture–recapture analysis. Survival was negatively associated with concentrations of OCs in the blood. The effect of OCs was nonlinear and evident only among birds with the highest concentrations (the uppermost deciles of contamination). The threshold for depressed survival differed between the sexes, with females being more sensitive to contamination. For birds with lower OC concentration, survival was very high, i.e. at the upper range of survival rates reported from glaucous and other large gull species in other, presumably less contaminated populations. We propose two non-exclusive explanations. First, at some threshold of OC concentration, parents (especially males) may abandon reproduction to maximize their own survival. Second, high contamination of OC may eliminate the most sensitive individuals from the population (especially among females), inducing a strong selection towards high-quality and less sensitive phenotypes.

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Asymmetric isolating barriers between different microclimatic environments caused by low immigrant survival

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2014.2459 ◽

2015 ◽

Vol 282 (1802) ◽

pp. 20142459 ◽

Cited By ~ 7

Author(s):

Thomas P. Gosden ◽

John T. Waller ◽

Erik I. Svensson

Keyword(s):

Gene Flow ◽

Local Adaptation ◽

Survival Rates ◽

Differential Survival ◽

Local Survival ◽

Local Selection ◽

The Common ◽

Source Sink ◽

Field Transplant ◽

Transplant Experiments

Spatially variable selection has the potential to result in local adaptation unless counteracted by gene flow. Therefore, barriers to gene flow will help facilitate divergence between populations that differ in local selection pressures. We performed spatially and temporally replicated reciprocal field transplant experiments between inland and coastal habitats using males of the common blue damselfly ( Enallagma cyathigerum ) as our study organism. Males from coastal populations had lower local survival rates than resident males at inland sites, whereas we detected no differences between immigrant and resident males at coastal sites, suggesting asymmetric local adaptation in a source–sink system. There were no intrinsic differences in longevity between males from the different environments suggesting that the observed differences in male survival are environment-dependent and probably caused by local adaptation. Furthermore, the coastal environment was found to be warmer and drier than the inland environment, further suggesting local adaptation to microclimatic factors has lead to differential survival of resident and immigrant males. Our results suggest that low survival of immigrant males mediates isolation between closely located populations inhabiting different microclimatic environments.

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Changing central Pacific El Niños reduce stability of North American salmon survival rates

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1503190112 ◽

2015 ◽

Vol 112 (35) ◽

pp. 10962-10966 ◽

Cited By ~ 70

Author(s):

D. Patrick Kilduff ◽

Emanuele Di Lorenzo ◽

Louis W. Botsford ◽

Steven L. H. Teo

Keyword(s):

Southern Oscillation ◽

Survival Rates ◽

Central Pacific ◽

Climate Effect ◽

Enso Events ◽

Northeast Pacific ◽

Management Actions ◽

Local Survival ◽

Portfolio Effect ◽

Ocean Conditions

Pacific salmon are a dominant component of the northeast Pacific ecosystem. Their status is of concern because salmon abundance is highly variable—including protected stocks, a recently closed fishery, and actively managed fisheries that provide substantial ecosystem services. Variable ocean conditions, such as the Pacific Decadal Oscillation (PDO), have influenced these fisheries, while diminished diversity of freshwater habitats have increased variability via the portfolio effect. We address the question of how recent changes in ocean conditions will affect populations of two salmon species. Since the 1980s, El Niño Southern Oscillation (ENSO) events have been more frequently associated with central tropical Pacific warming (CPW) rather than the canonical eastern Pacific warming ENSO (EPW). CPW is linked to the North Pacific Gyre Oscillation (NPGO), whereas EPW is linked to the PDO, different indicators of northeast Pacific Ocean ecosystem productivity. Here we show that both coho and Chinook salmon survival rates along western North America indicate that the NPGO, rather than the PDO, explains salmon survival since the 1980s. The observed increase in NPGO variance in recent decades was accompanied by an increase in coherence of local survival rates of these two species, increasing salmon variability via the portfolio effect. Such increases in coherence among salmon stocks are usually attributed to controllable freshwater influences such as hatcheries and habitat degradation, but the unknown mechanism underlying the ocean climate effect identified here is not directly subject to management actions.

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Annual Survival Rates of Wintering Sparrows: Assessing Demographic Consequences of Migration

The Auk ◽

10.1093/auk/119.1.149 ◽

2002 ◽

Vol 119 (1) ◽

pp. 149-165 ◽

Cited By ~ 10

Author(s):

Brett K. Sandercock ◽

Alvaro Jaramillo

Keyword(s):

Time Allocation ◽

Short Distance ◽

Evolutionary Ecology ◽

Migratory Birds ◽

Puget Sound ◽

Survival Rates ◽

Long Distance ◽

Zonotrichia Leucophrys ◽

Local Survival ◽

Melospiza Lincolnii

AbstractThe demographic consequences of migration have important implications for both evolutionary ecology and conservation biology. We investigated local survival rates for six populations of sparrows at a wintering site. Recent developments in mark–recapture statistics were applied to a 13 year dataset with large numbers of marked individuals (n = 1,632 to 4,394). The study taxa were closely related, and included one resident species (Song Sparrow [Melospiza melodia gouldii]), one short-distance migrant (“Puget Sound” White-crowned Sparrow [Zonotrichia leucophrys pugetensis]), two moderate-distance migrants (Lincoln's [Melospiza lincolnii] and Fox [Passerella iliaca] sparrow), and two long-distance migrants (“Gambel's” White-crowned [Zonotrichia leucophrys gambelii] and Golden-crowned [Zonotrichia atricapilla] sparrow). A literature review demonstrated a cline in fecundity among these sparrows: resident and short-distance migrants laid multiple clutches of few eggs, whereas long-distance migrants tended to produce one large clutch. Annual rates of local survival were low in the interval after first capture (<0.35), possibly because of variation in true survival, site-fidelity, presence of transients and heterogeneity of capture. Estimates of local survival among birds that returned at least once were more robust and were comparable among Song (0.558 ± 0.054 SE), Puget Sound White-crowned (0.461 ± 0.026), Lincoln's (0.456 ± 0.066), Fox (0.352 ± 0.0), Golden-crowned (0.422 ± 0.023) and Gambel's White-crowned (0.432 ± 0.0) sparrows. Estimates of survivorship for Lincoln's and Fox sparrows are among the first values available for those species. Local survival was not higher among resident than migratory taxa, nor did it covary with migration distance among migratory species. These results did not support the time-allocation hypothesis of Greenberg (1980), but are consistent with aspects of bet-hedging theory. While these analyses have potential implications for conservation of migratory birds, further work is required to establish whether these patterns are applicable to Neotropical migrants.

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