Apparent Survival Research Articles

Density effects on native and non‐native trout survival in streams

AbstractEnvironmental stressors associated with a changing climate and non‐native fish, individually, represent significant threats to native fish conservation. These threats can exacerbate risks to native fishes when conditions interact at the trailing edge of a population's distribution. We collected capture–mark–recapture data for Rio Grande cutthroat trout (RGCT, Oncorhynchus clarkii virginalis) at the trailing edge of all cutthroat trout distributions from eight northern New Mexico populations. We used a factorial sampling design from streams characterised as “cool” or “warm” and whether RGCT were sympatric with non‐native brown trout (Salmo trutta). We tested competing hypotheses that warm temperatures, reduced flows, high densities and sympatry with brown trout would negatively impact RGCT apparent survival rates. We found the strongest evidence for a non‐native trout interaction with total trout density affecting RGCT apparent survival rates. Our results are consistent with patterns observed in northern cutthroat trout populations where non‐native salmonids negatively impacted apparent survival rates. We also found that a negative density effect was observed on allopatric RGCT and sympatric brown trout apparent survival, but a positive density effect was observed for sympatric RGCT. These results suggest higher density populations of RGCT may be more resilient to displacement by non‐native trout than low‐density populations.

Migratory birds with delayed spring departure migrate faster but pay the costs.

Migratory birds that experience poor overwintering conditions are often late to arrive at the breeding grounds, which is known to depress individual fitness. Despite the importance of this carryover effect, few studies have investigated how individuals can modify migratory behaviors en route to reduce delays on arrival and whether accelerating migration incurs survival costs. To examine this, we used Motus Wildlife Tracking System to track individual American redstarts (Setophaga ruticilla) as they migrated from wintering grounds in Southwest Jamaica through Florida en route to their breeding areas. We leveraged long-term data on spring departure timing and breeding latitude to quantify the relative departure dates (early vs. delayed) of tagged individuals, which we then related to individual migration rates and apparent annual survival. Compared to those initiating migration earlier, individuals that departed relatively late (10-day delay) migrated at a 43% faster rate, which decreased their annual survival by 6.3%. Our results are consistent with the hypothesis that spring migrants use speed to compensate for departure delays despite incurring survival costs. This compensatory behavior may potentially underly differential survival during spring migration and may be particularly widespread across short-lived migratory birds generally considered time-constrained.

Climate-mediated population dynamics of a migratory songbird differ between the trailing edge and range core.

Understanding the demographic drivers of range contractions is important for predicting species' responses to climate change; however, few studies have examined the effects of climate change on survival and recruitment across species' ranges. We show that climate change can drive trailing edge range contractions through the effects on apparent survival, and potentially recruitment, in a migratory songbird. We assessed the demographic drivers of trailing edge range contractions using a long-term demography dataset for the black-throated blue warbler (Setophaga caerulescens) collected across elevational climate gradients at the trailing edge and core of the breeding range. We used a Bayesian hierarchical model to estimate the effect of climate change on apparent survival and recruitment and to forecast population viability at study plots through 2040. The trailing edge population at the low-elevation plot became locally extinct by 2017. The local population at the mid-elevation plot at the trailing edge gradually declined and is predicted to become extirpated by 2040. Population declines were associated with warming temperatures at the mid-elevation plot, although results were more equivocal at the low-elevation plot where we had fewer years of data. Population density was stable or increasing at the range core, although warming temperatures are predicted to cause population declines by 2040 at the low-elevation plot. This result suggests that even populations within the geographic core of the range are vulnerable to climate change. The demographic drivers of local population declines varied between study plots, but warming temperatures were frequently associated with declining rates of population growth and apparent survival. Declining apparent survival in our study system is likely to be associated with increased adult emigration away from poor-quality habitats. Our results suggest that demographic responses to warming temperatures are complex and dependent on local conditions and geographic range position, but spatial variation in population declines is consistent with the climate-mediated range shift hypothesis. Local populations of black-throated blue warblers near the warm-edge range boundary at low latitudes and low elevations are likely to be the most vulnerable to climate change, potentially leading to local extirpation and range contractions.

Climatic influences on survival and reproductive transitions of big-eared woodrats in California oak woodland

AbstractIt is known that climatic factors can influence the reproductive performance of small mammal populations. However, this information has not been available for the big-eared woodrat (Neotoma macrotis), a keystone species that inhabits the California central coast ranges south to Mexico and the oak woodlands (Quercus spp.) of the western Sierra Nevada foothills. From 2002 to 2014, we livetrapped woodrats on 1.1-ha study plots in coastal-central California and recorded their age and reproductive status. We analyzed these data by a capture-mark-recapture (CMR) framework to estimate state-specific recapture probability (p) and monthly apparent survival (S) of juvenile, non-reproductive, and reproductive adult female woodrats, and the influence of rain and temperature on S and transition probability (Ψ) of the three states. Rainfall from the previous season did not markedly affect survival rates of the states, with one exception: it decreased the survival of nonreproductive woodrats. Nearly all breeding occurred during the cool, wet winter season. Juvenile woodrats had at least a 0.55 probability of breeding by their first winter, conditional on survival. Temperature during the breeding season had a marked negative influence on transition probability. During winter, survival of nonreproductive adult females was significantly higher than for juvenile and reproductive females, indicating a cost of reproduction. Physiological effects and diminished diet quality due to further climate warming could reduce the reproductive success of female big-eared woodrats with negative consequences on population growth and persistence.

Apparent survival probability and abundance of juvenile green turtles in the foraging ground at Kuroshima Island, Ryukyu Archipelago

An understanding of the survival probability and abundance of endangered species is critical for their effective conservation and management. In this study, long-term capture-mark-recapture data were used to estimate the apparent survival probability and abundance of green turtles Chelonia mydas at Kuroshima Island in the Yaeyama Islands, Japan. A total of 453 turtles were captured from 2009 to 2020 using entangling nets. All captured turtles were juveniles and subadults; no adult turtles were captured during this study. The estimated apparent survival rate of this aggregation was 0.82 (95% CI = 0.76-0.86) using the Cormack-Jolly-Seber model, which accounts for both permanent emigration and death. Annual abundance was estimated using the Horvitz-Thompson estimator. Estimated abundance increased from 234 (95% CI = 182-286) in 2009 to 418 (95% CI = 325-510) in 2020. This trend in abundance for green turtles in the foraging ground may result from the increasing nesting population in this region. Our study provides information for understanding the life cycle of green turtles in the Yaeyama Islands and for the conservation and management of marine ecosystems in this region.

Updated systematic review and meta-analysis of extended adjuvant temozolomide in patients with newly diagnosed glioblastoma.

Contemporary standard-of-care for newly diagnosed glioblastoma (GBM) is maximal safe resection followed by postoperative focal conformal radiotherapy (RT) plus concurrent temozolomide (TMZ) and 6-cycles of adjuvant TMZ (Stupp regimen). However, many patients continue to receive extended adjuvant TMZ (beyond 6-cycles) without solid scientific evidence. This review pools data from nonrandomized studies and randomized controlled trials (RCTs) comparing extended adjuvant TMZ (>6-cycles) to standard adjuvant TMZ (6-cycles) in patients with newly diagnosed GBM for updated evidence-synthesis. This systematic review and meta-analysis was carried out in accordance with the Cochrane methodology including quality assessment of primary studies. Primary outcome of interest was comparative efficacy defined as progression-free survival (PFS) and overall survival (OS). Hazard ratios (HRs) for PFS and OS with corresponding 95% confidence interval (CIs) were extracted/computed from individual primary studies and pooled using random-effects model. Any p-value <0.05 was considered statistically significant. Evidence-synthesis was based on pooling of data from 2578 patients enrolled in 16 nonrandomized comparative studies and 5 RCTs. Overall, extended adjuvant TMZ was associated with statistically significant reduction in the risk of progression (HR = 0.72, 95%CI: 0.60-0.87; p = 0.007) and death (HR = 0.71, 95%CI: 0.57-0.90; p = 0.004) compared to standard adjuvant TMZ. However, on subgroup analysis, survival benefit of extended adjuvant TMZ was limited to data synthesized from retrospective nonrandomized comparative studies with no statistically significant difference in outcomes seen after pooling of data from RCTs only. Apparent survival benefit of extended adjuvant TMZ in newly diagnosed GBM is largely driven by nonrandomized comparative studies with high inherent potential for multiple biases.

Breeding populations of Marbled Godwits and Willets have high annual survival and strong site fidelity to managed wetlands.

The Prairie Pothole Region of central Canada supports a diverse community of breeding waterbirds, but many species have declining populations and the demographic mechanisms driving the declines remain unknown. We conducted a 7-year field study during 1995-2001 to investigate the demographic performance of Marbled Godwits (Limosa fedoa) and Willets (Tringa semipalmata) breeding in managed wetlands near Brooks, Alberta. Mark-recapture analyses based on Cormack-Jolly-Seber models revealed that the annual rates of apparent survival for Marbled Godwits ( =0.953 ± 0.012SE) and Willets ( =0.861 ± 0.015SE) are among the highest rates of survivorship reported for any breeding or nonbreeding population of large-bodied shorebirds. Our estimates of life expectancy for males were comparable to longevity records in godwits (17.3 years ±5.8SE vs. 25-29+ years) and willets (7.7 ± 1.5SE vs. 10+ years). The two species both showed strong breeding site fidelity but differed in rates of mate fidelity. Pairs that reunited and males that switched mates usually nested <300 m from their previous nests, whereas females that switched mates usually moved longer distances >1.1-1.5km. Returning pairs usually reunited in godwits (85%) but not in willets (28%), possibly because of species differences in adult survival or patterns of migration. Baseline estimates of annual survival for banded-only birds will be useful for evaluating the potential effects of new tracking tags or the environmental changes that have occurred during the past 20 years. Conservation strategies for large-bodied shorebirds should be focused on reduction of exposure to anthropogenic mortality because low rates of natural mortality suggest that losses to collisions at breeding sites or harvest at nonbreeding areas are likely to cause additive mortality.

Abstract A040: Race and socioeconomic factors associated with decreased survival in breast cancer, assessing for healthcare disparities using the National Cancer Database

Abstract Purpose: It has widely been shown that lower socioeconomic status (SES) is associated with worse survival in breast cancer patients. Some researchers suggested this disparity is driven by diagnosis at a more advanced stage and in patients with more pre-existing health conditions, while other groups have postulated that this disparity is driven by unequal treatment, including decreased access to systemic and radiation therapy. Our purpose was to determine whether a survival disparity in low SES groups still exists after controlling for these aforementioned factors. Methods: We queried the National Cancer Database (NCDB) for patients with nonmetastatic breast cancer of all stages diagnosed in 2004-2016 who underwent simple mastectomy with or without reconstruction, breast conserving surgery (BCS), or subcutaneous mastectomy (SCM). Hazard ratios (HRs) were calculated, adjusting for age, Charlson Comorbidity Index (CCI), receptor status, grade, laterality, clinical and pathological stage, number of positive nodes, surgery type, margin, systemic therapy, radiation, insurance, income, education level, urban-rural, and race. Results: From 2004 to 2016, 1,851,465 patients diagnosed with nonmetastatic breast cancer were treated with BCS, SCM, or mastectomy. Adjusted HRs revealed that low income remained independently associated with worse survival, at every income level when compared with the highest quartile (lowest vs highest median income quartile: aHR 1.23, 95% CI 1.19-1.27). Other demographic factors were also independently associated with worse survival, including increasing age (aHR 1.49, 95% CI 1.47-1.5), higher CCI (CCI 3+ vs 0: aHR 2.91, 95% CI 2.76-3.07), Black race (vs White: aHR 1.1, 95% CI 1.07-1.13), Medicaid insurance (vs Medicare: aHR 1.19, 95% CI 1.14-1.23), and low education level (second lowest vs highest high school graduation rate quartile: aHR 1.07, 95% CI 1.04-1.1). Many tumor and treatment factors were also independently associated with worse survival, with the strongest factors being triple-negative receptor cancer (vs ER+/PR+/Her2-: aHR 2.01, 95% CI 1.99-2.09), and pathologic stage 3 (vs stage I: aHR 2.04, 95% CI 1.95-2.13). Interestingly, there was a greater survival benefit observed in patients receiving mastectomy with reconstruction (vs BCS: aHR 0.63, 95% CI 0.61-0.65) versus those without reconstruction (vs BCS: aHR 0.98, 95% CI 0.95-1). Conclusion: In patients diagnosed with nonmetastatic breast cancer in the NCDB from 2004 to 2016, lower income, in addition to black race, Medicaid insurance, and lower educational level were all independently associated with worse survival. However, older age, higher CCI, and tumor factors were stronger predictors of decreased survival. The apparent survival advantage of mastectomy with reconstruction over that with no reconstruction was a surprising finding that could suggest the influence of unincluded demographic factors limiting access to reconstructive surgery. Citation Format: Thomas Norman, Lindsay Hwang, Xiaomeng Lei, Steven Cen, Jason Ye. Race and socioeconomic factors associated with decreased survival in breast cancer, assessing for healthcare disparities using the National Cancer Database [abstract]. In: Proceedings of the 15th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2022 Sep 16-19; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr A040.

See you in spring: overwinter survival is higher than post summer in the Alpine marmot

Animal species living in highly seasonal environments developed different strategies to cope with the periodical drastic change of environmental conditions. Hibernating mammals survive the winter season by reducing their activity and metabolism, and by centring their activities during the favourable season. Thus, the demography of these species depends upon both hibernating and active periods. In this study, we explored the apparent survival of Alpine marmots monitored between 2007 and 2018 in the North-Western Italian Alps. We fit Cormack-Jolly-Seber (CJS) models to quantify changes in the apparent survival and capture probability of marmots, after the hibernation phase and at the end of the summer. Apparent survival after winter almost reached 100% and it was higher than post-summer survival. Moreover, while post-summer apparent survival remained almost stable over lifetime, with a slight increase with age, characterised however by wide confidence intervals, overwinter survival decreased with age, especially after 6 years of age. No temporal trends, nor changes between areas at different elevations, were found. We suggest that these results arise from a combination of climatic conditions, predation pressure and social dynamics, which is a pivotal feature of this species and cannot be ignored when considering population dynamics of Alpine marmots.

Nomogram Model for Predicting the Prognosis of High-Grade Glioma in Adults Receiving Standard Treatment: A Retrospective Cohort Study

To identify the critical factors associated with the progression-free survival (PFS) and overall survival (OS) of high-grade glioma (HGG) in adults who have received standard treatment and establish a novel graphical nomogram and an online dynamic nomogram. This is a retrospective study of adult HGG patients receiving standard treatment (surgery, postoperative radiotherapy, and temozolomide (TMZ) chemotherapy) at Huashan Hospital, Fudan University between January 2017 and December 2019. We used uni- and multi-variable COX models to identify the significant prognostic factors for PFS and OS. Based on the significant predictors, graphical and online nomograms were established. A total of 246 patients were enrolled in the study based on the inclusion criteria. The average PFS and OS were 22.99 ± 11.43 and 30.51 ± 13.73 months, respectively. According to the multi-variable COX model, age, extent of resection (EOR), and IDH mutation were associated with PFS and OS, while edema index (EI) was relevant to PFS. In addition, patients with IDH and TERT promoter co-mutations had longer PFSs and OSs, and no apparent survival benefit was found in the long-cycle TMZ adjuvant chemotherapy compared with the standard Stupp protocol. Based on these critical factors, a graphical nomogram and online nomogram were developed for predicting PFS and OS, respectively. The calibration curve showed favorable consistency between the predicted and actual survival rates. C-index and time-dependent AUC showed good discrimination abilities. We identified the significant predictors for the PFS and OS of HGG adults receiving standard treatment and established user-friendly nomogram models to assist neurosurgeons in optimizing clinical management and treatment strategies.

Roadmap to recovery revealed through the reintroduction of an IUCN Red List species

Reintroductions are powerful tools for tackling biodiversity loss, but the resulting populations can be intrinsically small and vulnerable. It is therefore critical to maximise the number of individuals that are available to contribute to recovery efforts. To address this, we investigated how demographic parameters from a reintroduced population can reveal threats to long-term persistence, inform thresholds for management interventions, and create targets for removing an endangered species from the IUCN Red List. We calculated capture-mark-recapture population estimates for eastern quolls (Dasyurus viverrinus) which had been reintroduced to a fenced reserve in the Australian Capital Territory. We then incorporated the resulting demographic parameters into population viability analyses (PVAs) to estimate probabilities of persistence under several scenarios, including supplementations and harvests (removal of individuals for translocation to other locations). After determining sustainable harvest rates, we then ‘back-cast’ the population size and occupancy area required to remove the species from the IUCN Red List within 10 years. Our demographic results indicated high mean apparent survival (90% ± 5), and PVAs revealed the probability of persistence over a 50-year time horizon was 50.5% with no interventions, 0% when the population was harvested of > 6 individuals, and 100% if harvests ≤ 54 juveniles were combined with an annual supplementation of ten maternal females (with ≤ 6 young each). Based on this model, a total harvest area of 413 km2 and an occupancy area of 437 km2 would be needed to recover the species within 10 years (i.e., 90 similar fenced reserves, not accounting for edge effects). Due to the inherent difficulty in securing large areas for species recovery, we see these ambitious targets as a call to create coordinated and collaborative sanctuary networks where species can be managed as a metapopulation across multiple sites. By taking advantage of a rapid life history and harvesting the ‘doomed surplus’, managers can achieve their stretch goals for species recovery in the long term.

Comparing translocated beavers used as passive restoration tools to resident beavers in degraded desert rivers

AbstractWildlife translocation facilitates conservation efforts, including recovering imperiled species, reducing human–wildlife conflict, and restoring degraded ecosystems. Beaver (American, Castor canadensis; Eurasian, C. fiber) translocation may mitigate human–wildlife conflict and facilitate ecosystem restoration. However, few projects measure outcomes of translocations by monitoring beaver postrelease, and translocation to desert streams is relatively rare. We captured, tagged, and monitored 47 American beavers (hereafter, beavers) which we then translocated to two desert rivers in Utah, USA, to assist in passive river restoration. We compared translocated beaver site fidelity, survival, and dam‐building behavior to 24 resident beavers. We observed high apparent survival (i.e., survived and stayed in the study site) for eight weeks postrelease of resident adult beavers (0.88 ± 0.08; standard error) and lower but similar apparent survival rates between resident subadult (0.15 ± 0.15), translocated adult (0.26 ± 0.12), and translocated subadult beavers (0.09 ± 0.08). Neither the pre‐ nor the post‐translocation count of river reaches with beaver dams were predicted well by the Beaver Restoration Assessment Tool, which estimates maximum beaver dam capacity by river reach, suggesting beaver‐related restoration is not maximized in these rivers. Translocated beavers exhibited similar characteristics as resident subadult beavers during dispersal; they were more vulnerable to predation and many emigrated from the study sites. High mortality and low site fidelity should be anticipated when translocating beavers, but even so, translocation may have contributed to additional beaver dams in the restoration sites, which is the common goal of beaver‐assisted river restoration. Multiple releases at targeted restoration sites may eventually result in establishment and meet conservation objectives for desert rivers.

Real-world treatment patterns and outcomes of triple-class treated patients with multiple myeloma in the United States

ABSTRACT Objectives Although multiple myeloma (MM) survival has improved following the introduction of proteosome inhibitors, immunomodulatory drugs, and anti-CD38 therapies, patients become refractory to these agents. Real-world outcomes of triple-class exposed patients are limited and were investigated in this study. Methods The Integra Connect Database was used to assess the treatment patterns of triple-class exposed patients with relapsed/refractory MM (RRMM) (January 2016–December 2019). Results During this period, patients (N = 501) reached triple exposure in a median of three lines of therapy (LOTs) over 995 days. A new LOT was started in a median of 18 (1–691) days after triple exposure; 71% of the patients started a new LOT within 30 days. Throughout the follow-up period, 8% of the patients had a therapy gap greater than 90 days. Following triple exposure, 103/501 patients (21%) received only triple-class agents in subsequent LOTs, while 24 (4.8%) patients received only non–triple-class agents. The median apparent survival from initiation of first therapy after triple exposure was 308 days. Conclusion These results indicate that recycling of triple-class agents after previous exposure is widespread and prognosis in the RRMM population remains poor, highlighting the continuing unmet need for new agents with novel mechanisms to improve patient outcomes.

Annual apparent survival across species is lower in juvenile than adult birds but has similar ecological correlates

Annual survival is a key demographic trait influencing population growth and viability. Variability among species in annual survival tends to reflect different life history trajectories. In adult birds, greater annual survival has been shown to be associated with larger body mass, smaller clutch size, lower latitude, island living, flocking and cooperative breeding. Less attention has focused on the ecological correlates of survival in birds during the first year of life. Using a phylogenetic framework, I explored the correlates of annual juvenile survival across species worldwide. When measured concurrently at the same study sites, annual apparent survival in a sample of 338 species was strongly and positively associated with body mass and was typically at least half of adult survival. Lower annual survival in juveniles probably arises through inexperience, but mortality might be overestimated as juveniles tend to disperse more extensively than adults. In a separate analysis involving 610 survival estimates from 342 species, I examined the ecological correlates of annual apparent survival in juveniles. With the exception of migration, most ecological correlates of annual apparent survival in adults, such as body mass, latitude and island living also prevailed in juveniles. The findings support the idea that the ecological factors associated with greater survival in adults are similar in juveniles.

Female Grass Wrens adjust brooding effort according to ambient temperature, male feeding contribution and nest placement

The keystone of life‐history evolution theory proposes a trade‐off between current reproductive effort and future survival. Brooding is an essential and often overlooked component of parental behaviour of altricial birds intended to transfer heat to nestlings. Brooding under challenging environmental conditions can be energetically demanding and may adversely affect adult survival and future reproduction. We provide the first detailed description of the brooding behaviour of a south temperate grassland specialist: the Grass Wren Cistothorus platensis. In Grass Wrens, both sexes collaborate in parental care; however, only females brood the nestlings. We examined the relationship of ambient temperature, male feeding contribution, nestling age, nest size and nest placement in determining brooding behaviour. Additionally, we evaluated the effects of brooding behaviour on nestling body condition near fledging and female apparent survival. Brooding effort decreased with nestling age. Females increased their brooding effort at low ambient temperature and when males delivered more food. At lower ambient temperatures, females increased brooding effort in nests placed further from plant edge, with taller plant heights and well‐concealed substrates. However, there was no relationship between brooding effort and nest size. Neither female investment in brooding nor the number of nestlings produced per female was associated with nestling body condition near fledging or female annual apparent survival. Our results identify several factors that shape brooding behaviour in this south temperate passerine, suggesting that females favour nestling thermal conditions under adverse weather conditions.

No "carry-over" effects of tracking devices on return rate and parameters determining reproductive success in once and repeatedly tagged common swifts (Apus apus), a long-distance migratory bird.

To understand life-history strategies in migratory bird species, we should focus on migration behaviour and possible carry-over effects on both population and individual level. Tracking devices are useful tools to directly investigate migration behaviour. With increased use of tracking devices, questions arise towards animal welfare and possible negative effects of logger on birds. Several studies were conducted to address this question in birds that were tagged and tracked for one complete non-breeding season including migration but with mixed results. To detect individual-based decisions regarding migration strategy, we need to track the same individuals several times. So far, there are no studies investigating effects of repeatedly tagging on reproduction and life-history traits in individual migratory birds, especially in small birds. We used long-term data of 85 tagged common swifts (Apus apus), a long-distance migratory bird, of a breeding colony in Germany to test whether carrying a geolocator or GPS logger once or repeatedly during non-breeding season affected return rate, apparent survival, and parameters determining reproductive success. Additionally, we checked for individual differences in arrival date and breeding parameters when the same individuals were tagged and when they were not tagged in different years. Further, we calculated the individual repeatability in arrival at the breeding colony and date of egg laying in repeatedly tagged swifts. Once and repeatedly tagged birds returned to the colony at a similar rate as non-logger birds and arrived earlier than non-logger birds. We found no effect of logger-type on return rate in logger birds. We detected no differences in apparent survival, time lag to clutch initiation, date of clutch initiation, clutch size, number of chicks and fledglings between logger and non-logger birds. We found neither an effect of loggers nor of logger-types on the arrival date and breeding parameter on individual-level. Arrival date was highly repeatableand date of clutch initiation was moderately repeatable within repeatedly tagged individuals.

RWD36 Comparison of True Versus Apparent Survival in Patients With Metastatic Non-Small Cell Cancer Treated in the Real-World Setting

RWD36 Comparison of True Versus Apparent Survival in Patients With Metastatic Non-Small Cell Cancer Treated in the Real-World Setting

Impact of haemodialysis hours on outcomes in older patients.

Previous studies report an association between longer haemodialysis treatment sessions and improved survival. Worldwide, there is a trend to increasing age among prevalent patients receiving haemodialysis. This analysis aimed to determine whether the mortality benefit of longer haemodialysis treatment sessions diminishes with increasing age. This was a retrospective cohort study of people who first commenced thrice-weekly haemodialysis aged ≥65 years, reported to the Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry from 2005 to 2015, included from 90 days after dialysis start. The primary outcome was all-cause mortality. Cox regression analysis was performed with haemodialysis session duration the exposure of interest. Of 8224 people who commenced haemodialysis as their first treatment for kidney failure aged ≥65 years during this period, 4727 patients died. Longer dialysis hours per session was associated with a decreased risk of death in unadjusted analyses [hazard ratio, HR, for ≥5h versus 4 to <4.5h: 0.81 (0.75-0.88, p < .001)]. Patients having longer dialysis sessions were younger but had greater co-morbidity. In an adjusted model including age and other variables, the survival benefit of longer hours was only partially attenuated [HR for previous comparison: 0.75 (0.69-0.82, p < .001)], and no interaction between age and hours was demonstrated (p=.89). The apparent survival benefit associated with longer haemodialysis session length appears to be preserved in patients 65 years or older. In practice, the benefit of longer dialysis hours should be carefully weighed against other factors in this patient group.

Annual captures and low apparent survival rates in two tit species in western Hungary

AbstractAdult and juvenile survival are important factors affecting the population dynamics of small passerines. Understanding variation in the population dynamics and survival rates is critical for ecological studies and nature conservation. The aim of this study was to investigate the annual capture-recapture, apparent survival and capture probabilities of the Blue TitCyanistes caeruleusand the Great TitParus majoroccurring in western Hungary. Data from 8,628 Blue Tits and 7,727 Great Tits came from a constant-effort ringing scheme, using three ringing periods, spanning 24 years (1998 to 2021). The annual captures did not show a significant linear trend from 1998 to 2021 in the study site for both tit species. The temporal variation of annual captures and the annual capture-recapture proportions of different ages and sexes of the tit species were similar. This indicated that the migration strategies of these two partial migrant species did not differ significantly. According to the best standard Cormack-Jolly-Seber model, apparent survival of first-year birds was lower than that for adults. The CJS model selection for the dataset indicated that the time and sex had no effect on apparent survival probabilities for both tit species. Capture probability in the juvenile groups was not significantly higher than that in the adult groups for both species.

Climate‐driven stream‐flow impacts on bull trout metapopulation dynamics revealed by quantitative assessment of 22 years of tag–recapture data

Abstract Climate change has altered annual hydrologic cycles globally. Where stream flows are dominated by snow melt in western North America, climate change has resulted in peak flows that occur earlier in the runoff season and reduced flows during the non‐runoff season. Such changes can negatively affect the reproduction success and first‐year survival of stream‐dependent, autumn‐spawning salmonid fishes. We annually sampled bull trout (Salvelinus confluentus Suckley) populations in the St. Mary River catchment in north‐central Montana, U.S.A. Bull trout (≥ age 3; n = 3,502) electrofished from six creeks during 1998–2018 were given passive integrated transponder tags and 739 (21.1%) of those fish were recaptured through 2019 (tag loss c. 4.5%). We used tag–recapture data to (1) determine the spatial extent of the bull trout metapopulation; (2) fit a Bayesian Jolly–Seber model to identify the temporal trends in the sizes, finite growth rates (λ), and apparent survival and detection probabilities of the three main populations; and (3) assess the statistical associations between λ and flow. Bull trout movements among creeks defined the metapopulation's almost catchment‐wide spatial extent. Statistical correlations between λ and flow were clumped in the month × flow variable space at flow lags of 3–7 years, which corresponded with production of the dominant age classes in our tagged populations. Positive correlations occurred during June–September (the bull trout spawning season) and negative correlations during October–May (the embryo‐incubation period). Declining spawning‐season flow could have degraded bull trout spawning habitat, whereas increasing incubation‐period flow could have physically disturbed embryos affecting their survival. This study revealed associations between bull trout population dynamics and climate change as indexed by stream flow. Although the spawning habitats of these bull trout are protected within Glacier National Park and the occurrence of multiple local populations supports metapopulation persistence, that persistence is diminished because flow‐regime change has a strong negative influence on each population. Given the region's apparent climate trajectory, further decline in the bull trout metapopulation is anticipated.