Fringe Population Research Articles

Seasonal and Daily Movement Patterns by Wels Catfish (Silurus glanis) at the Northern Fringe of Its Distribution Range

Fish behavior often varies across a species’ distribution range. Documenting how behaviors vary at fringes in comparison to core habitats is key to understanding the impact of environmental variation and the evolution of local adaptations. Here, we studied the behavior of Wels catfish (Silurus glanis) in Lake Möckeln, Sweden, which represent a European northern fringe population. Adult individuals (101–195 cm, N = 55) were caught and externally marked with data storage tags (DSTs). Fifteen DSTs were recovered a year after tagging, of which 11 tags contained long-term high-resolution behavioral data on the use of vertical (depth) and thermal habitats. This showed that the catfish already became active in late winter (<5 °C) and displayed nocturnal activity primarily during summer and late autumn. The latter included a transition from the bottom to the surface layer at dusk, continuous and high activity close to the surface during the night, and then descent back to deeper water at dawn. During the daytime, the catfish were mainly inactive in the bottom layer. These behaviors contrast with what is documented in conspecifics from the core distribution area, perhaps reflecting adaptive strategies to cope with lower temperatures and shorter summers.

Climate change-induced shifts in survival and size of the worlds' northernmost oviparous snake: A 68-year study.

Because of their dependence on ambient temperature ectothermic animals can serve as sentinels of conservation problems related to global warming. Reptiles in temperate areas are especially well suited to study such effects, as their annual and daily activity patterns directly depend on ambient temperature. This study is based on annual data spanning 68 years from a fringe population of Grass Snakes (Natrix natrix), which is the world's northernmost oviparous (egg-laying) reptile, and known to be constrained by temperature for reproduction, morphology, and behavior. Mark-recapture analyses showed that survival probability was generally higher in males than in females, and that it increased with body length. Body condition (scaled mass index) and body length increased over time, indicative of a longer annual activity period. Monthly survival was generally higher during winter (i.e., hibernation) than over the summer season. Summer survival increased over time, whilst winter survival decreased, especially during recent decades. Winter survival was lower when annual maximum snow depth was less than 15 cm, implying a negative effect of milder winters with less insulating snow cover. Our study demonstrates long-term shifts in body length, body condition and seasonal survival associated with a warming climate. Although the seasonal changes in survival ran in opposite directions and though changes were small in absolute terms, the trends did not cancel out, but total annual survival decreased. We conclude that effects of a warming climate can be diverse and pose a threat for thermophilic species in temperate regions, and that future studies should consider survival change by season, preferably in a long-term approach.

Abstract TP94: Exploring Trends in LVO EVT Treatment of Fringe Patients by Race

Intro & Background: Following the publication of the randomized clinical trials in 2015 and 2018 on endovascular stroke therapy (EVT), procedural utilization has increased. Guidelines have since been developed and followed regarding cut-offs for patient treatment eligibility. Here, we explore the trends in EVT treatment of patients categorized as “fringe” patients by race. Methods & Materials: We performed a retrospective cross-sectional analysis using the SVIN Registry with records from 2010 to 2021. This dataset includes all LVO AIS patients that underwent EVT. Patients were categorized as “fringe” or “non-fringe” based on NIHSS (<6), ASPECTS (<6), pMRS (>1), proximal vs distal occlusion, last known well to arrival time (>24 hours), and age (>85). Fringe cutoffs were determined using typical guidelines. Outcomes were compared between White patients and Black/African American patients to determine trends in treating fringe patients with EVT. Chi-squared analyses were utilized for outcomes. Results: Among the 7,018 patients 4,791 patients were White and 1,821 patients were black. Median age was 69 (IQR: 58-79). Median NIHSS was 17 (IQR: 11-22). Focusing on the White and Black/AA patient population, a greater percentage of LVO patients that underwent EVT and were considered “fringe” were Black/AA patients (66% vs 71%). We also found that there are significant differences among these fringe categories: age, (20% vs 7.9%, p<0.001 white vs black), proximal occlusion (52% vs 58%, p<0.001, white vs black), and of having sICH (4.2% vs 2.8% p=0.03 white vs black). Comparing fringe categories between races, White patients were more likely to be >85 years of age, have a distal occlusion, and have sICH than Black/AA patients. Conclusion: The overall fringe population showed greater percentage of the white population which we speculate leads to higher percentage of white population in the SICH criteria, they are receiving more off-guideline treatment. These findings indicate that there may be a presence of racial bias in treatment decision-making that should be further explored. Further, there is proof that indications for EVT interventions are being expanded past guidelines in order to provide treatment for a wider range of patients.

Knowledge and Perception of Malaysian Forest Fringe Population towards Zika Infection

Knowledge and Perception of Malaysian Forest Fringe Population towards Zika Infection

Contribution of Non-Wood Forest Product to The Local Community Living Near Mangrove Forest in Kudat, Sabah

This study was conducted to identify the types of non-wood forest products from the mangrove forests that are used by people of the mangrove fringe, reviewing the contribution of non-wood forest product sales of mangrove forest on the edge of the mangrove population income sources and investigate the local use of mangrove’s non-wood forest products of socio-economic development of the mangrove fringe population. The method which was used is by distributing the questionnaires and carried out formal interviews with the respondents. The locations which were studied are Kampung Limau Limauan, Kampung Bukit Kelapa, Kampung Longgom Kecil and Kampung Indrasun Laut. The questionnaires comprises of three parts which the first, second and third parts are containing the information regarding on the demographic of the respondent, the inventory of the mangrove’s non-wood forest products which sells by the respondent and the contribution of the mangrove’s non-wood forest product to the development respondent’s socioeconomy respectively. The respondents as a whole are more than 53 people and only 13 people only involved in the recruitment of mangroves. Of the total, found only three respondents whoactually depend on the mangrove’s non-wood forest products, while 10 others were only made to take the job as a sideline of mangrove forests. The types of mangrove’s non-wood forest products stated are mangrove crab (Scylla sarrata), shell (Cerithidea obtuse), cat fish (Plotosus sp.), mullet fish (Valamugil seheli) and marine shell (Polymesuda expansa). However, only four out of six products are marketed which are marine shell, shell, and mangrove crab and cat fish while the other is for domestic purposes. Based on data collected on correlation of the relationship between the average incomes of non-wood forest product sales of mangrove forests with a total average monthly income of respondents, it shows a positive relationship with r=0.527. The value of contribution of the average income from the selling of mangrove’s non-wood forest product over the total average of monthly income is 28.7 %. The Local usage value of mangrove’s product is calculated based on the formula of Local usage value = ?Pi Qi – Ci. The value of the local use non-wood forest products from the mangrove forests which are marketed by RM 1924.40 per month while the total value of products marketed locally applied to each individual is at RM 148.03 a month. As a conclusion,mangrove forests do contribute to the development of residence’s socio-economy although the value is low.

Knowledge and Perception of Malaysian Forest Fringe Population towards Zika Infection

The World Health Organization (WHO) has declared Zika infection as Public Health Emergency of International Concern in 2016. In this study, we aimed to assess the knowledge and risk perception towards Zika infection among the forest fringe population in Malaysia. A cross-sectional study of with 433 adult respondents in Malaysia completed the assisted-administered validated questionnaire on knowledge and perception to Zika infection. Bidirectional analysis on the person and item abilities were tested using Statistical Package for the Social Sciences (SPSS) and Rasch. The knowledge and perception levels were tested against significant sociodemographic or socioeconomic variables using Pearson’s Chi Square; covariates were then adjusted at multivariate level using binary logistic regression. Both knowledge and perception domains were well-targeted. Complementing results from SPSS and Rasch showed poor knowledge and poor risk perception levels in slightly more than half of the respondents [knowledge score: 50.8% (SPSS), 55.4% (Rasch); perception score: (58.0% (SPSS), 58.2% (Rasch)]. With covariates adjusted, non-bumiputra (non-natives) of higher education level, higher household income and recent jungle visits showed good knowledge level. Adult, menopaused women from Perak state showed better risk perception level towards Zika. Majority of the forest fringe population in Malaysia have poor knowledge and risk perception towards the Zika infection. This questionnaire is a suitable tool to assess knowledge and perception towards Zika infection among the forest fringe populations in Southeast Asia.

Multisource noninvasive genetics of brown bears (Ursus arctos) in Greece reveals a highly structured population and a new matrilineal contact zone in southern Europe.

In human‐dominated landscapes, connectivity is crucial for maintaining demographically stable mammalian populations. Here, we provide a comprehensive noninvasive genetic study for the brown bear population in the Hellenic Peninsula. We analyze its population structuring and connectivity, estimate its population size throughout its distribution, and describe its phylogeography in detail for the first time. Our results, based on 150 multilocus genotypes and on 244‐bp sequences of the mtDNA control region, show the population is comprised by three highly differentiated genetic clusters, consistent with geographical populations of Pindos, Peristeri, and Rhodope. By detecting two male bears with Rhodopean ancestry in the western demes, we provide strong evidence for the ongoing genetic connectivity of the geographically fragmented eastern and western distributions, which suggests connectivity of the larger East Balkan and Pindos‐Dinara populations. Total effective population size (N e) was estimated to be 199 individuals, and total combined population size (N C) was 499, with each cluster showing a relatively high level of genetic variability, suggesting that migration has been sufficient to counteract genetic erosion. The mtNDA results were congruent with the microsatellite data, and the three genetic clusters were matched predominantly with an equal number of mtDNA haplotypes that belong to the brown bear Western mitochondrial lineage (Clade 1), with two haplotypes being globally new and endemic. The detection of a fourth haplotype that belongs to the Eastern lineage (Clade 3a1) in three bears from the western distribution places the southernmost secondary contact zone between the Eastern and Western lineages in Greece and generates new hypotheses about postglacial maxima migration routes. This work indicates that the genetic composition and diversity of Europe's low‐latitude fringe population are the outcome of ancient and historical events and highlight its importance for the connectivity and long‐term persistence of the species in the Balkans.

Functions of Borrowings in the Russian Argot

The article explores and describes the functions of borrowings which, at different time peri-ods, entered the argot of Russian fringe population groups. The main purpose of the study is to present a systematizing critical review of the existing literature on the functions of argot and to describe the characteristic features of borrowed argotisms found in Russian literary texts as well as Russian explanatory, etymological, and foreign word dictionaries. The author uses the methods of description and comparison, the comparative method, and the opposition method. Since the general criminal argot, the specialized argot, and the prison argot are rich in their forms and functionality, they perform a number of important tasks, and gradually pene-trate into literary speech. Thus a careful study of their functions helps to explain some of the linguistic realities of the modern Russian language and throws a fresh light on the psychology of native Russian speakers. After analyzing a diverse body of sources, the author identifies sixteen separate functions of borrowed words that are common for the general, specialized, and prison argot, namely: service, secret, identification, nominative, worldview, expressive, utilitarian, communicative, signaling, magic, pseudo-aesthetic, agitation, and game function as well as the function of gender determinism, the function of intimidation, and, finally the function of stylistic characterization of literary characters through their speech. The results of the research can be used in college-level courses of modern Russian for law and language students, in special courses in social linguistics and cultural studies as well as in language and public speaking courses in schools and universities.

Chytrid fungus dynamics and infections associated with movement distances in a red‐listed amphibian

AbstractAmphibians are among the most threatened vertebrate taxa due to anthropogenic habitat change and emerging pathogens. The fungus Batrachochytrium dendrobatidis (Bd) may cause trade‐offs between the immune responses and other important functions, such as mobility. The pool frog (Pelophylax lessonae) is red‐listed in Sweden, and an earlier study conducted in our study area did not detect the fungus. In this study, 67 Swedish pool frogs were tested for Bd. Of these, 28 adults were provided with external radio transmitters and tracked during the summer and autumn to compare movement among infected and non‐infected individuals. Additionally, we tested some individuals for Bd twice during the summer to study intra‐seasonal variation in individual infections. Our results suggest that Bd has recently invaded these pool frog populations. During autumn, movement distances of infected pool frogs were shorter compared to uninfected individuals, and summer movements within ponds were reduced by increasing Bd load. We also found that the frogs can clear (or reduce) Bd infection during their active season. The results from this study increase understanding of the implications of Bd infections in an anuran fringe population, as well as in amphibian metapopulations, and can further guide amphibian conservation planning and management.

Genetic evidence for male‐biased dispersal in the Siberian jay (Perisoreus infaustus) based on autosomal and Z‐chromosomal markers

Sex-bias in natal dispersal patterns can have important genetic and evolutionary consequences; however, reliable information about sex-biased dispersal can be difficult to obtain with observational methods. We analysed the sex-specific patterns of genetic differentiation among three Siberian jay (Perisoreus infaustus) populations, using 11 autosomal and six Z-chromosomal microsatellite markers. Irrespective of marker-type and indices used (viz. F(ST), average pairwise relatedness and effective number of immigrants), all analyses provided strong evidence for male-biased dispersal. Population structuring at autosomal loci (F(ST) =0.046, P<0.05) exceeded that at Z-chromosomal loci (F(ST) =0.033, P<0.05), and levels of introgression were inferred to be significantly higher for Z-chromosomal when compared to autosomal loci. Of the three populations studied, levels of genetic variability were the lowest in the southernmost fringe population, despite the fact that it harboured a group of divergent Z-chromosomal haplotypes that were not found in the other two populations. In general, the results provide strong genetic evidence for male-biased dispersal in Siberian jays, where observational data have previously suggested male philopatry. The results also highlight the utility of Z-chromosomal markers for gaining insights into the genetic diversity and structuring of populations.

Looking at terrorism through left realist lenses

While terrorism has moved into the spotlight of criminological study, including critical criminology, it has yet to be thoroughly explored from a left realist perspective. Left realism addresses four aspects of crime: causes of offending, impact on the victims, and both official and public responses to crime. A left realist approach to terrorism would argue that similar to those who engage in street crimes, many terrorists are socially or economically disenfranchised young men who become involved in terrorism through connections with similarly situated members of the fringe population, and “get tough” policies on terrorism will backfire. Four propositions of left realist theory organized by DeKeseredy and colleagues are presented and addressed through the extant literature, which offers partial support for a left realist explanation of terrorism.

Rapid urbanization - Its impact on mental health: A South Asian perspective

Rapid increase in urban population as a proportion of total population is resulting in rapid urbanization of the world. By the end of 2008, a majority of the world's population will be living in the cities. This paradigm shift in the dynamics of human population is attracting attention of demographers, sociologists, scientists, and politicians alike. Urbanization brings with it a unique set of advantages and disadvantages. Though it is driving the economies of most of the nations of the world, a serious concern regarding the impact of urbanization on mental health is warranted. The impact of urbanization on mental health in South-Asian countries needs to be examined. These countries by virtue of their developing economies and a significant proportion of population still living below poverty line are particularly vulnerable and tend to have a higher burden of diseases with an already compromised primary health care delivery system. The range of disorders and deviancies associated with urbanization is enormous and includes psychoses, depression, sociopathy, substance abuse, alcoholism, crime, delinquency, vandalism, family disintegration, and alienation. Thus, it is a heterogenous mix of problems and categorizing them to one particular subtype seems daunting and undesirable. Urbanization is affecting the entire gamut of population especially the vulnerable sections of society - elderly, children and adolescents, and women. Rapid urbanization has also led to creation of “fringe population” mostly living from hand to mouth which further adds to poverty. Poverty and mental health have a complex and multidimensional relationship. Urban population is heavily influenced by changing cultural dynamics leading to particular psychiatric problems like depression, alcoholism, and delinquency. Judicious use of resources, balanced approach to development, and sound government policies are advocated for appropriate growth of advancing economies of South-Asian region.

Porous landscapes – The case of Greater Copenhagen

Many blueprints for urban development argue for the benefits of a sharp distinction between rural and urban space. While such planning designs have been quite successful in maintaining a physical distinction between rural and urban, major transformations of the socio-economic environment in peri-urban areas are creating a more diffuse and porous interface. This paper examines socio-economic consequences of the current transformation of peri-urban areas. Three themes are selected for analysis: changing economies, overall impact of urbanisation as perceived by the individual farm owner and the degree of their local orientation and engagement. Based on case studies in Greater Copenhagen, longitudinal trends and details of the current situation are analysed. In addition, by differentiating between newcomers and long-term residents, possible future changes are indicated. The analysis shows that the importance of agriculture has declined, whereas other gainful activities and residential use have increased. Thus, the functions of the local economy and community are changing. An increasing proportion of the farm owners appreciate the proximity to urban agglomerations (public services, shopping, public transport, social relationships and markets), but this location also has drawbacks, for example in terms of uncertainty concerning future urban development, inconveniences for agricultural production and problems related to public access to private properties. Differences between newcomers and long-time residents are identified. Newcomers without any agricultural background are frequent. They often work outside the municipality and are more frequently personally involved in other gainful activities on-farm. Newcomers perceive more problems related to people accessing the farm properties and are less involved in local activities. In combination, these trends indicate possible future increase in conflicts between farm owners and the public and that the local engagement may be declining. The analysis, however, also shows similarities between newcomers and long-time residents, and therefore does not indicate the development of two cultures or “two nations”. Rather, the urban fringe population is becoming more heterogeneous, ranging from full-time farmers to residents with their social and professional network outside the local area or people engaging in non-agricultural business on-farm.

Municipal Underbounding: Annexation and Racial Exclusion in Small Southern Towns*

Abstract This paper examines patterns of annexation, including municipal “underbounding,” in nonmetropolitan towns in the South; that is, whether blacks living adjacent to municipalities are systematically excluded from incorporation. Annexation‐or the lack of annexation‐can be a political tool used by municipal leaders to exclude disadvantaged or low‐income populations, including minorities, from voting in local elections and from receiving access to public utilities and other community services. To address this question, we use Tiger files, GIS, and other geographically disaggregated data from the Summary Files of the 1990 and 2000 decennial censuses. Overall, 22.6 percent of the fringe areas “at risk” of annexation in our study communities was African American, while 20.7 percent of the areas that were actually annexed during the 1990s was African American. However, communities with large black populations at the fringe were significantly less likely than other communities to annex at all‐either black or white population. Largely white communities that faced a “black threat”‐which we defined in instances where the county “percent black” was higher than the place “percent black”‐were also less likely to annex black populations during the 1990s. Finally, predominately white communities were much less likely to annex black populations, even when we controlled for the size of the black fringe population at risk of annexation. Such results provide evidence of racial exclusion in small southern towns.

Nesting and Reproductive Activities of Greater Sage-Grouse in a Declining Northern Fringe Population

AbstractIn Canada, Greater Sage-Grouse (Centrocercus urophasianus) are at the northern edge of their range, occurring only in southeastern Alberta and southwestern Saskatchewan. The population in Canada has declined by 66% to 92% over the last 30 years. We used radio-telemetry to follow 20 female Greater Sage-Grouse and monitor productivity in southeastern Alberta, and to assess habitat use at nesting and brood-rearing locations. All females attempted to nest. Mean clutch size (7.8 eggs per nest) was at the high end of the normal range for sage-grouse (typically 6.6–8.2). Nest success (46%) and breeding success (55%) were within the range found for more southerly populations (15% to 86% and 15% to 70%, respectively). Thirty-six percent of unsuccessful females attempted to renest. Fledging success was slightly lower than reported in other studies. Thus, reproductive effort does not appear to be related to the population decline. However, chick survival to ≥50 days of age (mean = 18%) was only about half of that estimated (35%) for a stable or slightly declining population, suggesting that chick survival may be the most important factor reducing overall reproductive success and contributing to the decline of Greater Sage-Grouse in Canada.Actividades de Anidación y Reproducción de Centrocercus urophasianus en una Población del Extremo Norte en DecliveResumen. En Canadá, Centrocercus urophasianus está en el extremo norte de su distribución, encontrándose sólo en el sureste de Alberta y el suroeste de Saskatchewan. La población de Canadá ha disminuido entre el 66% y 92% durante los últimos 30 años. Utilizamos radio-telemetría para seguir a 20 hembras de C. urophasianus y monitorear su productividad en el sureste de Alberta y para evaluar el uso de hábitat en sitios de anidación y de cría de los pichones. Todas las hembras intentaron anidar. El tamaño promedio de la nidada (7.8 huevos por nido) estuvo en el extremo superior del rango normal de C. urophasianus (típicamente 6.6–8.2). El éxito de anidación (46%) y de reproducción (55%) estuvieron dentro de los rangos encontrados en poblaciones de más al sur (15% a 86% y 15% a 70%, respectivamente). El treinta y seis por ciento de las hembras que no tuvieron éxito intentaron volver a anidar. El éxito en la crianza de polluelos hasta la etapa de volantones fue ligeramente menor que el reportado en otros estudios. Por lo tanto, el esfuerzo reproductivo no parece estar relacionado con el declive poblacional. Sin embargo, la supervivencia de los polluelos hasta 50 días de edad o más (promedio = 18%) fue sólo aproximadamente la mitad de lo que se ha estimado para una población estable o en ligero declive (35%), lo que sugiere que la supervivencia de los pichones podría ser el factor más importante reduciendo el éxito reproductivo en general y contribuyendo al declive de C. urophasianus en Canadá.

Predictors of Moral Thought in Two Contrasting Adolescent Samples

This study investigated the consistency of the finding that family cohesion and adaptability are significant predictors of adolescent moral thought. To test this, 175 adolescents from a metropolitan population (Sample 1) and 146 from an urban fringe population (Sample 2) were administered White's (1997) revised Moral Authority Scale, Olson et al.'s (1992) Family Adaptability and Cohesion Evaluation Scale, and a family demographic questionnaire. A linear relation between family cohesion and family and equality sources of moral authority was found in both samples. However, the significant linear relation between family adaptability and total source influence score found in Sample 1 was not found in Sample 2. This finding might result from the heterogeneity of sociocultural factors across the samples; post hoc analyses suggested that sociocultural factors might play an important moderating role in the relation between family adaptability and adolescent moral thought.

The Future Population of Australia's Coastal Lands

In 1986 about 26 per cent of the Australian population lived in the country's coastal fringe. In recent decades coastal fringe population has increased at the same rate as the population elsewhere and, if this proportion holds as total population grows towards a projected level of 27 million by 2051, plausibly there could be another three million people living in the coastal fringe by then. This paper examines, in synoptic fashion, and within the limits of available data, the capacity of the coastal fringe to absorb such population increments.

Photosynthetic inorganic carbon assimilation byPrasiola stipitata(Prasiolales, Chlorophyta) under emersed and submersed conditions: Relationship to the taxonomy ofPrasiola

Material from a marine littoral fringe population of Prasiola stipitata exhibited inorganic C saturation of photosynthesis when emersed but hydrated in air (35 Pa CO2) and when submersed in sea-water (2 mol m-3 inorganic C, pH 8·0). This high affinity for inorganic C was accompanied by a low CO2 compensation concentration and the capacity to use external HCO- 3. No CAM-like behaviour was exhibited in either emersed or submersed specimens. The δ13C of the alga was -21·18%. These characteristics resemble those of several other high-intertidal algae and of a high-intertidal cyanobacterial lichen which have been tested. The inorganic C metabolism processes examined do not distinguish between the Ulvophyceae and the Pleurastrophyceae as the most appropriate location for Prasiola, although chlorophyll a:chlorophyll b ratios (including measurements on three pleurastrophycean supratidal lichens) and polyol occurrence favour the Pleurastrophyceae as the higher taxon to which the Prasiolales should be referred.

“Cocaine-Related” Deaths: Media Coverage in the War on Drugs

A 1989 newspaper story describing twenty-nine cocaine-related deaths in British Columbia is used to illustrate the lands of unwarranted inferences that are propagated by the news media during the current War on Drugs. The newspaper story conveys the impression that most of the deaths involved well-integrated, moderate drug users, that all twenty-nine deaths were caused by cocaine, and that these deaths provided evidence of an epidemic of dangerous cocaine use sweeping the province. However, the coroner's files on which the story was based, and related research, provide strong evidence that all three frightening inferences are wrong. A more careful analysis of these deaths as a consequence of chronic deterioration in a fringe population can contribute to the development of realistic drug policy.

Thermal preference in the pool frog Rana lessonae: impact on the reproductive behaviour of a northern fringe population

A documented warmth preference in the pool frog Rana lessonae is also expressed in the reproductive behaviour of a northern fringe population (60°N). During the breeding period of 31 days, individually marked frogs were observed during chorus. Male choruses were formed in the warmest parts of the pond, but moved between three areas. At night, these areas maintained the highest water temperatures in the pond, especially at low temperatures prevailing in the beginning of the breeding period. Oviposition occurred in the current chorus areas, and 86% took place during the first two weeks of the breeding period. That the choruses and oviposition changed locations within the favourable breeding areas can be explained by a pronounced thermal preference in the frogs, and winds moving the warm surface water in different directions.The water temperature required to initiate oviposition was 16°C, which is similar to those reported from related more southern populations. The thermal preference expressed in the breeding behaviour of both sexes and the tendency for early oviposition may be behavioural responses to environmental constraints on reproduction in the short season at 6O°N.