Seeds are an important life cycle stage because they guarantee plant survival in unfavorable environmental conditions and the transfer of genetic information from parents to offspring. However, similar to every organ, seeds undergo aging processes that limit their viability and ultimately cause the loss of their basic property, i.e., the ability to germinate. Seed aging is a vital economic and scientific issue that is related to seed resistance to an array of factors, both internal (genetic, structural, and physiological) and external (mainly storage conditions: temperature and humidity). Reactive oxygen species (ROS) are believed to initiate seed aging via the degradation of cell membrane phospholipids and the structural and functional deterioration of proteins and genetic material. Researchers investigating seed aging claim that the effective protection of genetic resources requires an understanding of the reasons for senescence of seeds with variable sensitivity to drying and long-term storage. Genomic integrity considerably affects seed viability and vigor. The deterioration of nucleic acids inhibits transcription and translation and exacerbates reductions in the activity of antioxidant system enzymes. All of these factors significantly limit seed viability.
Spatial ecology of red deer Cervus elaphus is shaped by both natural and anthropogenic factors. We used radio telemetry to investigate factors affecting habitat selection on two spatial scales, home range sizes and migratory behaviour of red deer (N = 8 individuals) in two mountain ranges of the western Carpathians in 2004–2007. The two study areas differed in terms of environmental conditions: Beskid Sądecki had higher altitudes, higher human population and road density and milder winters than Beskid Niski. Red deer in both areas selected forests and avoided agricultural habitats on both spatial scales. Elevation affected site selection only in Beskid Sądecki: deer selected higher altitudes for their home ranges, but lower altitudes within them. Deer avoided major roads when selecting their home ranges in both sites, but only in Beskid Sądecki, they also avoided roads within their home ranges. Deer in both study sites selected locations closer to supplementary feeding sites in winter. In years with more severe winters, deer in Beskid Niski displayed seasonal migration to south-facing slopes. Deer in Beskid Sadecki showed short-distance altitudinal movements from low elevations in winter to high elevations in summer, and a short-term descent to low elevations in August–September. Our results fit the general concept that climatic conditions and human-related factors shape spatial behaviour in ungulates, and that snow conditions are particularly important for migration. Climate change will likely contribute to diminishing migration in red deer in the Carpathians.
It is postulated that melanism in ectotherms is adaptive by enhancing thermoregulation, subsequent resource acquisition, and growth. Such effects may differ between the sexes as a result of the differential costs of self-maintenance and reproduction, but empirical support for the sex-specific consequences of melanism remains inconsistent. We studied the effects of melanism on body size and sex ratio in a population of the European grass snake (Natrix natrix) in SE Poland and also carried out a systematic review of the literature on the consequences of melanism in terrestrial snakes. Melanistic grass snakes of both sexes appeared to be smaller than the typical phenotype, which indicates higher predation pressure and minimal thermal benefits for black individuals. A female-biased sex ratio was observed in the typical phenotype, but not in melanistic snakes, suggesting that the costs for females and/or benefits for males are higher in melanistic individuals. In conjunction with earlier studies, our data indicate that the consequences of melanism may be related to the reproductive mode of species. In viviparous species, melanism tends to improve growth and/or body size and is more frequent in females, whereas the opposite holds for oviparous snakes. Further studies on melanism should examine a wider array of species with different reproductive strategies and traits beyond the usual thermal benefits.
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