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21.
Asuka Koyama Chika Egawa Hisatomo Taki Mika Yasuda Natsumi Kanzaki Tatsuya Ide Kimiko Okabe 《Urban Ecosystems》2018,21(6):1113-1122
In urban and suburban ecosystems, biodiversity can depend on various non-native plant species, including crop plants, garden plants and weeds. Non-native plants may help to maintain biodiversity by providing a source of forage for pollinators in these ecosystems. However, the contribution of plants in urban and agricultural areas to ecosystem services has often been underestimated in biodiversity assessments. In this study, we investigated the pollen sources of native honeybees (Apis cerana) in an arboretum containing native trees and urban and agricultural plants in a suburban landscape. We surveyed the flowering tree species planted inside the arboretum, which were potential pollen sources. The number of potential pollen-source species of native trees peaked in June and July and decreased after August. We collected A. cerana pollen balls every month and identified plant species of pollen in the collected pollen balls using DNA barcoding. In total, we identified 29 plant species from A. cerana pollen balls. The probability of A. cerana using pollen from urban and agricultural plants was higher in July and August than in June. A. cerana collected pollen forages from native tree species (53%), but also gathered pollen from crop plants (13%), garden trees (19%) and native and non-native weeds (14%); the predominant pollen sources in September and October were the garden tree Ulmus parvifolia and the non-native weed Solidago altissima. We found that native honeybees used plants from a variety of habitats including non-native plants to compensate for apparent seasonal shortages of native tree sources in suburban ecosystems. Our results highlight the importance of assessments of both positive and negative roles of non-native plants in urbanized ecosystems to improve biodiversity conservation. 相似文献
22.
This paper examines the effect of the polytechnic reform on geographical mobility. A polytechnic, higher education reform took place in Finland in the 1990s. It gradually transformed former vocational colleges into polytechnics and also brought higher education to regions that did not have a university before. This expansion of higher education provides exogenous variation in the regional supply of higher education. The reform raised the mobility of high school graduates across local labour markets in the years after they had completed their secondary studies, which indicated increased mobility between high school and post-secondary education. We estimate that the reform enhanced the annual migration rate of high school graduates by 1.2 percentage points over a 3-year follow-up period. This represents a substantial increase, because their baseline migration rate is 3.7 %. The effect fades several years after the completion of secondary studies. 相似文献
23.
ABSTRACTIn order to decrease physical child abuse, measures to recognize parents' abuse potential are needed. In this article, cross-cultural validation of the Child Abuse Potential (CAP) Inventory, an American measure was used to screen child abuse potential in families. Data were collected in 2012 from Finnish families expecting a baby at maternity and child welfare clinics. The data come from 380 families, including 375 mothers and 303 spouses. The validation was conducted separately for mothers and spouses and was based on basic psychometric properties, such as reliability estimates, abuse scale construct validity, and the abuse scale factor structure. The internal consistency of the abuse scale was high among both the mothers and the spouses. There were some differences in abuse construct validity and the abuse scale factor structure compared to the original measure, which was written in English and tested in an American sample. Those differences were, however, similar to those found by other studies that used translated versions of the inventory. In summary, the CAP Inventory was found to be a valid screening tool for professionals to assess parents' child abuse potential in Finnish service settings, and therefore its implementation is recommended in maternity and child welfare clinics. The validation supports the cross-cultural use of the CAP Inventory and future research on the subject. 相似文献
24.
This article examines the effect of AIDS-related mortality of the prime-age adult population on marriage behavior among women in Malawi. A rise in prime-age adult mortality increases risks associated with the search for a marriage partner in the marriage market. A possible behavioral change in the marriage market in response to an increase in prime-age adult mortality is to marry earlier to avoid exposure to HIV/AIDS risks. We test this hypothesis by using micro data from Malawi, where prime-age adult mortality has drastically increased. In the analysis, we estimate the probability of prime-age adult mortality that sample women have observed during their adolescent period by utilizing retrospective information on deaths of their siblings. Empirical analysis shows that excess prime-age adult mortality in the local marriage market lowers the marriage age for females and shortens the interval between the first sex and first marriage. 相似文献