Snow leopards are one of the least known large cats,the population of which has dramatically decreased.Their habitat loss was considered the main reason for the decline during the last decade,but their habitat preferences are still not well known.In this paper,we studied the winter habitat preferences of snow leopards in the Tomur National Nature Reserve(TNNR)in Northwest China during 2004–2005.We used sign surveys and transects to study the winter habitat selection of snow leopards.The results indicated that snow leopards showed a preference for habitat variabilities in slope aspect,vegetation cover,dominant topographical features,landform ruggedness and grazing status.We found that prey availability and dominant topographical features were the most important factors that determined the winter habitat selection of snow leopards.Our results supported the idea that the habitat preferences of snow leopards are a tradeoff between suitable habitat features and avoidance of potential human interactions. 相似文献
A nationwide recreational fishing survey in Sweden was used to estimate the benefits of recreational fishing in Sweden. The survey targeted the Swedish population and, consequently, the sample contained a large fraction of zero fishing days. To consider this, a zero-inflated Poisson model was used in the estimations. Swedes fished about 15.6 million days in 2013, of which two-thirds were spent on inland fishing, and one-third on marine and coastal fishing. Expected consumer surplus per fishing day varied with the season; SEK 193 for winter fishing, SEK 787 for summer fishing and SEK 95 for autumn fishing. Although about 70 per cent of total fishing days were spent on inland fishing, the weighted consumer surplus per fishing day in marine and coastal areas were higher. The results also demonstrated strong positive effects of increases in expected catch per day on number of fishing days demanded and consumer surplus, which have important implications for fishery policies directed at recreational fishing. 相似文献
In the planning processes of urban forests there are frequent conflicting opinions about the extent to which forests should be managed. On the one hand, management is needed to deal with the intensive use of forests, as well as unfavourable growing conditions, security factors and aesthetic variables. On the other hand, there is an increasing demand for unmanaged areas which is based primarily on ecological arguments. This paper presents research that was conducted in connection with the participatory planning process of Helsinki City forests. The main aim of this research was to study whether aesthetic and ecological values can be combined in the management of urban forests. Furthermore, the stability of forest landscape preferences during the participatory planning process was studied, along with the representativeness of planning groups compared to larger user groups. The data was collected in planning group meetings and public hearings in Helsinki during 1998–2000. Respondents evaluated a set of photographs designed to cover the main conflict situations in urban forest management: Thinnings, understorey management, the leaving of dead snags and decaying ground-wood.
These results show that the majority of residents in Helsinki prefer managed forests. The preferences are, however, closely connected to the background characteristics of respondents. Younger residents with a higher education and active urban forest users prefer more ecologically-oriented management when compared to older residents with less education, or less active users. The individuals had a rather clear and relatively stable opinion of what constitutes suitable management in urban forests, but the views differed considerably as a whole. This means that a participatory planning process will typically lead to some type of compromise. Moreover, the planning groups in Helsinki reflected the opinions of the larger user groups rather well. This indicates that the currently used participatory planning approach sufficiently integrates public values into its planning process. 相似文献
Rice (Oryza sativa L.) provides a life support system to millions of resource-poor farmers in rainfed environments; however, yields are very low because of various biotic and abiotic stresses. Submergence caused by typhoons and floods is one of the major reasons for production losses. Because of the complexity of these ecosystems, the breeding framework necessitates adequate feedback and a more in-depth understanding of the ecological and socioeconomic conditions in these flood-prone areas. Within this purview, this study validated the performance in farmers’ fields of lines with the SUB1 gene that confers tolerance of submergence for up to two weeks. The SUB1 gene was incorporated through marker-assisted backcrossing, MABC. The evaluation was conducted through participatory approaches to gain understanding of the risks as well as farmers’ preferences for these varieties. A baseline survey of 658 farm households accomplished during 2008, focus group discussions, key informant interviews, and adaptability trials were conducted, with focus on farmers commonly affected by submergence in four Southeast Asian countries: the Philippines, Lao PDR, Indonesia, and Southern Viet Nam. The study further examined farmers’ criteria in evaluating new varieties through the participatory varietal selection (PVS) process. Results showed that varying conditions of submergence can influence farmers’ criteria and preferences for rice cultivars. Depending on the timing of flood with respect to growth stage, shorter duration and shallow flashfloods can result in less than 10% production losses while deeper and stagnant water with two weeks’ duration and >100 cm depth can cause damage ranging from 40% to 77%. Major findings of PVS trials and preference analysis indicated that farmers prefer rice cultivars that are tolerant of submergence, have early to medium maturity relative to their commonly grown varieties, are resistant to pests and diseases, and are resistant to lodging, among other traits. To enhance adoption, male and female farmers should be involved in the evaluation process. The results of this study can contribute to enhancing breeding programs to develop appropriate varieties that reduce production losses, improve income, and ultimately reduce poverty incidence in submergence-prone areas. 相似文献
Red clover (Trifolium pratense L.) is becoming increasingly important in grassland systems because of its high productivity, protein content and nitrogen-fixing
ability, but its use has been constrained by losses due to pests and diseases, and this contributed to the decline of red
clover usage allowing white clover (T. repens L.) to become the dominant legume of UK grasslands. One of the major pests of red clover is the clover root weevil (Sitona lepidus Gyllenhal, Coleoptera, Curculionidae) which attacks both the shoots and roots, particularly the N-fixing root nodules, of
clover plants. This current work investigates the feeding preferences of S. lepidus with respect to 11 varieties (Pawera, Kuhn, Astra, Norseman, Norseman low, Norseman high, Marcom, Merviot, Milvus, Britta,
Sabtoron) and 5 lines (AA30, AA31, AA4493, AA4494 and AA4495) of red clover in order to identify relationships between the
variation in attractiveness of different red clover varieties for both adult and larval stages of the weevil. Of those tested
Norseman high showed potential resistance, being less favoured by both adults and larvae of the weevil. This may be attributed
to the potentially high phyto-oestrogen levels in this variety. 相似文献
Partial preference for feeds in ruminants is a well-documented phenomenon although their explanation can be elusive. The hypothesis was tested that sheep offered herbage of two annual grass species differing in chemical composition free-choice would select a diet that would maximize the nutritive value of the diet compared with sheep offered each herbage separately through a greater nutrient balance and synchronization of nutrient release for efficient ruminal microbial function. Fifteen male lambs were placed into metabolic cages, and randomly assigned to three treatments ( n = 5): Italian ryegrass fresh herbage (treatment R), barley fresh herbage (treatment B) or free-choice Italian ryegrass and barley fresh herbage (treatment RB). Both herbages had similar crude protein concentrations but Italian ryegrass herbage had higher concentration of water-soluble carbohydrates and lower concentration of fibre than barley herbage. Lambs were exposed to the treatments for 15 d. Lambs on treatment RB showed a partial preference of 0·82 (s.e. 0·031) for Italian ryegrass. Lambs on treatment RB had higher intakes of digestible dry matter and higher values for nitrogen retention than lambs on treatment B although similar to that of lambs on treatment R. The results for the dietary choices were not always consistent with maximizing the nutritive value of the diet. Other explanations, such as lambs needed to sample and track the nutritive value of dietary options or there was the development of transient food aversions, were also possible. 相似文献
Main stream commercial onion breeders do not select varieties for organic farming, but solely for conventional farming. Seed
companies consider the organic market too small to justify investments in breeding for this sector. In order to study if their
varieties also suit organic farmers’ needs we interviewed four Dutch commercial onion breeders on their breeding programme
and selection criteria and compared the outcome with a variety profile composed of the priority traits of Dutch organic farmers.
Breeders gave priority to the same storage and bulb quality traits that are demanded by organic farmers, because organic onions
are exported to conventional supermarkets that apply the same quality standards to organic and conventional onions. However,
organic farmers also need varieties that perform well in the field. Breeders give low priority to field selection. Furthermore,
three of the four seed companies only breed hybrids. The cytoplasmic male sterility system used to produce these hybrids does
not comply with organic principles. We conclude that at present breeders can provide varieties that meet organic farmers’
demands for storability and quality traits, but they should give higher priority to field selection to also improve required
field traits. The latter will only occur, if in future the organic seed market will grow. If the organic sector wants varieties
developed according to its own principles, it should either set up its own onion breeding programme or seek alliances with
breeding companies that are prepared to harmonize their breeding methodology with the organic principles. 相似文献