scholarly journals Predation and survival in reintroduced populations of the Common hamster Cricetus cricetus in the Netherlands

2020 ◽  
Vol 100 (6) ◽  
pp. 569-579
Author(s):  
Maurice J. J. La Haye ◽  
Ruud J. M. van Kats ◽  
Gerard J. D. M. Müskens ◽  
Caspar A. Hallmann ◽  
Eelke Jongejans
Keyword(s):  
The Netherlands ◽  
Survival Rates ◽  
Agricultural Practices ◽  
Adult Survival ◽  
Cricetus Cricetus ◽  
Active Season ◽  
Common Hamster ◽  
Viable Population ◽  
Survival And Reproduction ◽  
Small Mustelids

AbstractEuropean populations of Common hamster (Cricetus cricetus) have dramatically declined in the last decades, and in many EU countries, the species is on the brink of extinction. In the Netherlands, a research and reintroduction program was started in three areas with hamster-friendly management to reverse the decline of the species. Since 2002, more than 800 captive-bred and wild-born hamsters were monitored using implant radiotransmitters to quantify survival rates and discover the main causes of death after release compared to those of wild individuals. Individuals with a transmitter were regularly checked at their burrow. Predation by foxes, birds of prey, and small mustelids was the most important cause of mortality of this medium-sized rodent, while crop type and harvest regime were also likely to be important drivers as they influenced survival rates through the presence or absence of protective cover. The fitted weekly survival model showed that male hamsters had much lower survival rates during the active season than females, which corresponds with the ‘risky male hypothesis’. Survival rates of females appeared too low to keep populations at a stable level. To establish a viable population, more optimal environmental conditions for both survival and reproduction of the hamsters are necessary. Using electric fences around fields with hamsters significantly increased the survival of females. However, hamster conservationists need to consider not just subadult and adult survival rates, but also habitat connectivity, weather effects on reproduction, and alternative agricultural practices on a landscape scale.

Migration distance is a fundamental axis of the slow-fast continuum of life history in boreal birds

The Auk ◽  
2021 ◽  
Author(s):  
Benjamin M Winger ◽  
Teresa M Pegan
Keyword(s):  
Life History ◽  
Survival Rates ◽  
Reproductive Investment ◽  
Seasonal Migration ◽  
Adult Survival ◽  
Vital Rates ◽  
Long Distance ◽  
Migration Distance ◽  
Breeding Grounds ◽  
Survival And Reproduction

Abstract Seasonal migration is intrinsically connected to the balance of survival and reproduction, but whether migratory behavior influences species’ position on the slow-fast continuum of life history is poorly understood. We found that boreal-breeding birds that migrate long distances exhibit higher annual adult survival and lower annual reproductive investment relative to co-distributed boreal species that migrate shorter distances to winter closer to their breeding grounds. Our study uses “vital rates” data on reproductive output and survivorship compiled from the literature for a species assemblage of 45 species of mostly passerine birds. These species breed sympatrically in North American boreal forests but migrate to a diversity of environments for the northern winter. After controlling for body size and phylogeny, migration distance and apparent annual adult survival are positively related across species. Both migration distance and survival are positively correlated with wintering in environments that are warmer, wetter, and greener. At the same time, longer migrations are associated with reduced time spent on the breeding grounds, lower clutch sizes, and lower fecundity (clutch size × maximum number of broods per year). Although seasonal migration is often associated with high mortality, our results suggest that long-distance migration imposes selection pressures that both confer and demand high adult survival rates. That is, owing to the reproductive cost of long-distance migration, this strategy can only persist if balanced by high adult survival. Our study supports the idea that migration evolves to promote survival of species breeding in seasonal environments. In boreal birds, the evolution of the longest migrations yields the highest survival, but at an inherent cost to annual fecundity. Our results therefore reveal migratory distance as a fundamental axis of the slow-fast continuum that predicts, and is inextricable from, the balance of survival and reproduction.

Studies on Cepaea III. Ecogenetics of a population of Cepaea nemoralis (L.) subject to strong area effects

1968 ◽  
Vol 253 (789) ◽  
pp. 447-482 ◽  
Keyword(s):  
Survival Rates ◽  
Adult Survival ◽  
Frequency Variation ◽  
Snail Population ◽  
Differential Survival ◽  
Active Season ◽  
Cepaea Nemoralis ◽  
Area Effects ◽  
Colour Morphs ◽  
Morph Frequency

On the discovery of area effects in morph frequency variation in the snail Cepaea nemoralis on the Marlborough Downs (Cain & Currey 1963 a) an intensive study with mark-release-recapture methods of a population subject to these effects was begun. The area investigated was divided into four quarters (downland grass) and two nettlepatches; the snail population is continuous through the area. Frequent visits were made during the snails’ active season in 1962, 1963 and 1964; in 1965 and 1966 a single large sample was collected, marked and released in the spring. Five-banded shells are absent. The scoring of mid-bandeds with reduced bands being difficult, attention was concentrated on the principal colour morphs, yellow, pink and brown. Thrushes were predating the snails heavily in 1962, but the hard winter of 1962/3 removed them, and they have not yet returned in any numbers; the snail population does not seem to have been affected by this hard season. Throughout the period of investigation, the density of snails in the nettlepatches has been about ten times that in quarters 2, 3 and 4. Quarter 1 has less than half the density in the other quarters, and differs markedly from them and the nettlepatches in morph frequency, although it resembles quarter 2 strongly in vegetation. It is likely, therefore, that the snails are extremely localized in their wanderings, the more so as we had to collect from each division, take the samples away to be marked, and scatter them on release, each at random in its own division. Our estimates of migration from one division to another also suggest strong localization and perhaps homing. The total population in the area is about 3000 adults. Subpopulations have decreased in all divisions from 1963 to 1965. Adult survival rates are high, about 0.65 per year; no differential survival of the colour classes has been found, but much more data are needed. Predation by thrushes in 1962 was heavy in the summer, but not in proportion to snail density; the nettlepatches were proportionately much less predated, probably because of their dense growth of herbage. Winter predation, by contrast, was almost entirely in the nettlepatches, then showing expanses of bare earth. A check on our own efficiency of collecting shows that we are taking non-random samples in the quarters (downland grass) but not in the nettlepatches. We find pinks rather more conspicuous than yellows, but dark browns much less conspicuous than either. As the snails’ bodies in this area are very dark, yellows appear green, pinks dirty straw-colour. It seems unlikely that browns are really more cryptic visually than yellows. Possibly their behaviour is different. The samples of predated shells taken by the thrushes agree very closely with our samples, and it appears that they also are predating with a bias (missing browns) in the quarters but not in the nettlepatches. Morph frequencies show no sign of alteration in the period of investigation, except that in 1963 and 1964 there was a drop in percentages of browns in quarters 2, 3 and 4, apparently not continuing in 1965 and 1966. (The compensatory increase is shared equally between pinks and yellows.) This could well be due to the sudden cessation of selection by thrushes, but the rate seems excessive if there was selection only on adults. There is no obvious relation between morph frequencies and population density. The growth in size of the juveniles in our samples has been studied through the snails’ active season. It is clear that they take two years to reach maturity (i.e. to form the lip terminating the adult shell). This finding and the survival rates give a minimum generation interval of four years, and the actual period may be close to five in this area.

scholarly journals Sustainable Agriculture: Nutritional Benefits of Wheat–Soybean and Maize–Sunflower Associations for Hibernation and Reproduction of Endangered Common Hamsters

2021 ◽  
Vol 13 (24) ◽  
pp. 13521
Author(s):  
Mathilde Louise Tissier ◽  
Florian Kletty ◽  
Jean-Patrice Robin ◽  
Caroline Habold
Keyword(s):  
Reproductive Success ◽  
Large Scale ◽  
Agricultural Practices ◽  
Nutritional Deficiencies ◽  
Nutrient Deficiencies ◽  
Vitamin B3 ◽  
Common Hamster ◽  
Survival And Reproduction ◽  
Vitamin B3 Deficiency ◽  
Nutritional Benefits

Farmland species face many threats, including habitat loss and malnutrition during key periods of their life cycle. This is aggravated in conventionally managed monocultures, leading to nutrient deficiencies that impair the survival and reproduction of farmland wildlife. For instance, protein deficiencies in wheat or vitamin B3 deficiency in maize reduce by up to 87% the reproductive success of the critically endangered common hamster (Cricetus cricetus), a flagship species of European farmlands. It is urgent to identify and implement agricultural practices that can overcome these deficiencies and help restoring hamsters’ reproductive success. As part of a conservation program to diversify farming habitats in collaboration with farmers, we tested whether associations between wheat or maize and three supplemental crops (soybean, sunflower and fodder radish) supported hamsters’ performance during hibernation and reproduction. We observed that maize–sunflower, maize–radish and wheat–soybean associations minimized hamsters’ body mass loss during hibernation. The wheat–soybean association led to the highest reproductive success (N = 2 litters of 4.5 ± 0.7 pups with a 100% survival rate to weaning), followed by maize–sunflower and maize–radish. These crop associations offer promising opportunities to overcome nutritional deficiencies caused by cereal monocultures. Their agronomic potential should promote their implementation on a large scale and benefit farmland biodiversity beyond the common hamster.

scholarly journals A Demo-Genetic Analysis of a Small Reintroduced Carnivore Population: The Otter (Lutra lutra) in The Netherlands

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Maelle Seignobosc ◽  
Lia Hemerik ◽  
Hans Peter Koelewijn
Keyword(s):  
The Netherlands ◽  
Conservation Strategy ◽  
Adult Survival ◽  
Vital Rates ◽  
Negative Effects ◽  
Modelling Framework ◽  
Animal Populations ◽  
Female Survival ◽  
Survival And Reproduction ◽  
The Right

Assessing the viability of reintroduced animal populations is a complicated task. Reintroductions are usually carried out with a small number of individuals, thereby, limiting the possibilities for monitoring because of the possible negative effects of intensive monitoring on survival and reproduction. Moreover, reintroduction studies are part of a socioeconomic interplay of forces, thereby, also limiting monitoring possibilities. Also, knowledge of population demography and abundance can be incomplete or unattainable. Here, we illustrate how we combined traditional telemetry and novel non-invasive genetic methodology to construct a detailed life table of a small reintroduced otter population in The Netherlands. Combining an appropriate capture-mark-recapture framework with a matrix modelling approach provides, in general, useful insights for such populations. The data indicated that (i) male survival is lower than female survival, (ii) the reintroduced population is currently growing (estimatedλ=1.26: range [1.06, 1.42]) and seems viable, (iii) increasing adult survival is currently the critical stage at which efforts of field managers should concentrate, and (iv) the modelling framework allowed us to determine the boundary conditions for the vital rates under which the population would go extinct. The applied approach directs at measurements that help field managers to implement the right conservation strategy after reintroductions.

scholarly journals The evolution of seasonal migration and the slow-fast continuum of life history in birds

2020 ◽  
Author(s):  
Benjamin M. Winger ◽  
Teresa M. Pegan
Keyword(s):  
Life History ◽  
Boreal Forests ◽  
Survival Rates ◽  
Seasonal Migration ◽  
Adult Survival ◽  
Migratory Species ◽  
Long Distance ◽  
Evolutionary Context ◽  
Survival And Reproduction ◽  
Northern Winter

AbstractSeasonal migration is a widespread adaptation in environments with predictable periods of resource abundance and scarcity. Migration is frequently associated with high mortality, suggesting that migratory species live on the “fast” end of the slow-fast continuum of life history. However, few interspecific comparative studies have tested this assumption and prior assessments have been complicated by environmental variation among breeding locations. We evaluate how migration distance influences the tradeoff between reproduction and survival in 45 species of mostly passerine birds that breed sympatrically in North American boreal forests but migrate to a diversity of environments and latitudes for the northern winter. We find, after accounting for mass and phylogeny, that longer distance migrations to increasingly amenable winter environments are correlated with reduced annual reproductive output, but also result in increased adult survival compared to shorter-distance migrations. Non-migratory boreal species have life history parameters more similar to long-distance migrants than to shorter-distance migrants. These results suggest that long-distance migration and other highly specialized strategies for survival in seasonal environments impose selection pressures that both confer and demand high adult survival rates. That is, owing to the reproductive cost of long-distance migration, this strategy can only persist if balanced by high adult survival. Our results reveal migratory distance as a fundamental life history parameter that predicts, and is inextricable from, the balance of survival and reproduction. Our study further provides evolutionary context for understanding the annual cycle demography of migratory species and the strategies long-distance migrants use to maximize survival on their journeys.

Persistence of giants: population dynamics of the limpet Scutellastra laticostata on rocky shores in Western Australia

2020 ◽  
Vol 646 ◽  
pp. 79-92
Author(s):  
RE Scheibling ◽  
R Black
Keyword(s):  
Population Dynamics ◽  
Western Australia ◽  
Size Structure ◽  
Survival Rates ◽  
Maximum Size ◽  
High Rate ◽  
Adult Survival ◽  
Rocky Shores ◽  
Adult Size ◽  
Decadal Time Scale

Population dynamics and life history traits of the ‘giant’ limpet Scutellastra laticostata on intertidal limestone platforms at Rottnest Island, Western Australia, were recorded by interannual (January/February) monitoring of limpet density and size structure, and relocation of marked individuals, at 3 locations over periods of 13-16 yr between 1993 and 2020. Limpet densities ranged from 4 to 9 ind. m-2 on wave-swept seaward margins of platforms at 2 locations and on a rocky notch at the landward margin of the platform at a third. Juvenile recruits (25-55 mm shell length) were present each year, usually at low densities (<1 m-2), but localized pulses of recruitment occurred in some years. Annual survival rates of marked limpets varied among sites and cohorts, ranging from 0.42 yr-1 at the notch to 0.79 and 0.87 yr-1 on the platforms. A mass mortality of limpets on the platforms occurred in 2003, likely mediated by thermal stress during daytime low tides, coincident with high air temperatures and calm seas. Juveniles grew rapidly to adult size within 2 yr. Asymptotic size (L∞, von Bertalanffy growth model) ranged from 89 to 97 mm, and maximum size from 100 to 113 mm, on platforms. Growth rate and maximum size were lower on the notch. Our empirical observations and simulation models suggest that these populations are relatively stable on a decadal time scale. The frequency and magnitude of recruitment pulses and high rate of adult survival provide considerable inertia, enabling persistence of these populations in the face of sporadic climatic extremes.

scholarly journals Warming Arctic summers unlikely to increase productivity of shorebirds through renesting

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sarah T. Saalfeld ◽  
Brooke L. Hill ◽  
Christine M. Hunter ◽  
Charles J. Frost ◽  
Richard B. Lanctot
Keyword(s):  
Climate Change ◽  
Survival Rates ◽  
The Arctic ◽  
Adult Survival ◽  
Chick Survival ◽  
Ecological Processes ◽  
Bird Populations ◽  
Phenological Mismatch ◽  
Daily Survival ◽  
Adequate Food

AbstractClimate change in the Arctic is leading to earlier summers, creating a phenological mismatch between the hatching of insectivorous birds and the availability of their invertebrate prey. While phenological mismatch would presumably lower the survival of chicks, climate change is also leading to longer, warmer summers that may increase the annual productivity of birds by allowing adults to lay nests over a longer period of time, replace more nests that fail, and provide physiological relief to chicks (i.e., warmer temperatures that reduce thermoregulatory costs). However, there is little information on how these competing ecological processes will ultimately impact the demography of bird populations. In 2008 and 2009, we investigated the survival of chicks from initial and experimentally-induced replacement nests of arcticola Dunlin (Calidris alpina) breeding near Utqiaġvik, Alaska. We monitored survival of 66 broods from 41 initial and 25 replacement nests. Based on the average hatch date of each group, chick survival (up to age 15 days) from replacement nests (Ŝi = 0.10; 95% CI = 0.02–0.22) was substantially lower than initial nests (Ŝi = 0.67; 95% CI = 0.48–0.81). Daily survival rates were greater for older chicks, chicks from earlier-laid clutches, and during periods of greater invertebrate availability. As temperature was less important to daily survival rates of shorebird chicks than invertebrate availability, our results indicate that any physiological relief experienced by chicks will likely be overshadowed by the need for adequate food. Furthermore, the processes creating a phenological mismatch between hatching of shorebird young and invertebrate emergence ensures that warmer, longer breeding seasons will not translate into abundant food throughout the longer summers. Thus, despite having a greater opportunity to nest later (and potentially replace nests), young from these late-hatching broods will likely not have sufficient food to survive. Collectively, these results indicate that warmer, longer summers in the Arctic are unlikely to increase annual recruitment rates, and thus unable to compensate for low adult survival, which is typically limited by factors away from the Arctic-breeding grounds.

scholarly journals EPID-18. TRENDS IN INCIDENCE AND SURVIVAL OF MALIGNANT PEDIATRIC CENTRAL NERVOUS SYSTEM TUMORS IN THE NETHERLANDS

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii322-iii322
Author(s):  
Raoull Hoogendijk ◽  
Jasper van der Lugt ◽  
Dannis van Vuurden ◽  
Eelco Hoving ◽  
Leontien Kremer ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
The Netherlands ◽  
Malignant Gliomas ◽  
Survival Rates ◽  
Tumor Patients ◽  
Netherlands Cancer Registry ◽  
Malignant Astrocytomas ◽  
Brainstem Tumors ◽  
The Impact

Abstract BACKGROUND Variation in survival of pediatric central nervous system (CNS) tumors is large between countries. Within Europe, the Netherlands had one of the worst reported survival rates of malignant CNS (mCNS) tumors during 2000–2007. METHODS Using the Netherlands Cancer Registry, we evaluated trends in incidence and survival of pediatric mCNS tumors (behavior /3, 5th digit in the morphology code) diagnosed between 1990–2017. RESULTS 839 newly-diagnosed mCNS tumor patients &lt;18 years were registered between 1990–2017. Incidence of mCNS tumors remained stable (average incidence rate, 21.6 per million person-years). However, an increased incidence of malignant gliomas, NOS was found (Estimated Annual Percentage Change (EAPC) 11.6% p&lt;0.001). This appears to be related to a registration shift between 1990–1999 and 2000–2009 as brainstem tumors increased (+25%, n=79) for astrocytomas and other gliomas but decreased (-31%, n=32) for unspecified intracranial and intraspinal neoplasms. Overall, 5-year observed survival (5Y-OS) of mCNS tumors increased from 51% in 1990–1999 to 61% in 2010–2017 (P-for-trend&lt;0.001). This increase was not constant over time, as 5Y-OS for the period 2000–2009 was 47%. The only significant decrease in survival was found for malignant astrocytomas and other gliomas with a 5Y-OS of 56% in 1990–1999 decreasing to 48% in 2010–2017 (P-for-trend&lt;0.001). CONCLUSION Between 1990–2017 incidence of mCNS tumors in the Netherlands remained stable and survival increased. However, a decrease in survival was seen for malignant astrocytomas and other gliomas, which is partially explained by the registration shift of brainstem tumors. The impact of this shift on survival for all mCNS tumors is subject to further research.

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