Long-Term Population Changes of Native and Introduced Birds in the Alaka'i Swamp, Kaua'i

Abstract:  Within the last 30 years, five endemic bird species of the Alaka'i Swamp, Kaua'i, Hawai'i, have likely gone extinct. We documented population trends of the remaining avifauna in this time period to identify a common pattern in the Hawaiian Islands: decline of native species and expansion of introduced species. We conducted bird surveys over 100 km² of the Alaka'i and Kōke'e regions of Kaua'i in March–April 2000 to estimate population size, distribution, and range limits of seven native and six introduced forest birds. We compared the results with four previous surveys conducted over the last 30 years. Five of the seven native species we studied have fared well, maintaining sizeable populations (>20,000 individuals) and unchanged or increasing numbers. The endemic 'Akikiki ( Oreomystis bairdi ), however, declined from 6296 (SE ± 1374) to 1472 (SE ± 680) individuals and exhibited range contraction from 88 to 36 km². The 'I'iwi ( Vestiaria coccinea ) also experienced a decline and contraction, though not as severe. Populations of several introduced forest birds are increasing, but all species, excluding the Japanese White-eye ( Zosterops japonicus ), were at low numbers (<5,500 individuals in survey area). One introduced species, the Japanese Bush-Warbler ( Cettia diphone ) recently invaded, whereas another, the Red-billed Leiothrix ( Leiothrix lutea ), has been extirpated. Two hurricanes in the past 20 years appear to have most strongly affected nectarivores and may have contributed to the decline or extinction of several other species. Overall, native bird populations on Kaua'i have exhibited species-specific responses to limiting factors. Although most native populations appear stable, the extant native avifauna is vulnerable as a result of limited distributions and the potential for widespread habitat degradation.     

Effects of Human Subsistence Activities on Forest Birds in Northern Kenya

Abstract: Indigenous tribes and conservation biologists may have common goals and may be able to collaborate on the maintenance of biodiversity, but few researchers have evaluated the impacts and potential benefits of human subsistence activities. I studied the effects of subsistence activities (primarily wood collection) of nomadic pastoralists in 3 Afromontane forests of northern Kenya. In surveys of 404, 25‐m‐radius plots, I recorded vegetation structure and composition of the forest bird community. Plots with higher levels of human activity had significantly different vegetation structure, with more‐open canopies, more grass, and fewer tree stems. Nectarivores (abundance +231%) and aerial insectivores (+66%) were more abundant in plots with more‐intense wood collecting than in plots with less human activity, whereas abundance of forest specialists (?28%) decreased in plots with more‐intense human activity. Abundance of 58% of the bird species either increased or decreased significantly in plots with more‐intense human activity. Generally, the number of individuals of forest specialists decreased (6 of 7 species showed significant responses) and the number of individuals of edge and nonforest species increased with increasing human activity. Canonical correspondence analysis showed that an intensification of human activities would favor nectarivores, aerial insectivores, granivores, and omnivores and would negatively affect large‐sized, ground‐foraging species and arboreal frugivores. Subsistence human activities favored the invasion of forest by edge species at the expense of forest specialists; thus, further intensification of forest exploitation by local peoples is not recommended. At the same time, however, subsistence activities in northern Kenya forests appeared to increase the structural diversity of the vegetation and provided suitable habitat for part (but not all) of the forest avifauna, which suggests that subsistence human activities may have a role in the maintenance of bird diversity.     

石油化工物料长输管线安全设计问题探讨

针对石油化工物料长输管线设计、审查过程中存在的问题进行了较为全面的分析,并提出了解决的方法,为进一步完善相关工程设计规范和如何有效地执行这些规范提供了实例,给同类工程提供有益借鉴。     

Teratological effects of pesticides in vertebrates: a review

Abstract

In the last decades, the use and misuse of pesticides in the agriculture have increased, having a severe impact on ecosystems and their fauna. Although the various effects of pesticides on biodiversity have been already documented in several studies, to our knowledge no consistent overview of the impact of pesticides in vertebrates, both terrestrial and aquatic, is available. In this review, we try to present a concise compilation of the teratogenic effects of pesticides on the different classes of vertebrates – mammals, birds, reptiles, amphibians and fish.     

Conservation Value of Clustered Housing Developments

Abstract:  Traditionally, exurban lands in Colorado have been subdivided into a grid of parcels ranging from 2 to 16 ha. From an ecological perspective, this dispersed pattern of development effectively maximizes the individual influence of each home on the land. Clustered housing developments, designed to maximize open space, are assumed to benefit plant and wildlife communities of conservation interest. They have become a popular alternative for rural development despite the lack of empirical evidence demonstrating their conservation benefits. To better inform rural land-use planning, we evaluated clustered housing developments by comparing their spatial pattern with that of dispersed housing developments and by comparing their conservation value with that of both dispersed housing developments and undeveloped areas in Boulder County, Colorado. We used four indicators to assess conservation value: (1) densities of songbirds, (2) nest density and survival of ground-nesting birds, (3) presence of mammals, and (4) percent cover and proportion of native and non-native plant species. Clustered and dispersed housing developments did not differ on the majority of variables we examined. Both types of housing development had significantly higher densities of non-native and human-commensal species and significantly lower densities of native and human-sensitive species than undeveloped areas. More rigorous ecological guidelines and planning on a regional scale may help create clustered developments with higher conservation value.     

Ecological Effectiveness of Agri-Environment Schemes in Different Agricultural Landscapes in The Netherlands

Abstract:  Agri-environment schemes are an instrument used by western European countries to counteract the negative effects of contemporary agriculture on biodiversity, but not much is known about their effectiveness. We investigated the ecological effects of Dutch agri-environment schemes aimed at promoting botanical diversity or meadow birds, and we tested whether the effectiveness of the schemes depends on landscape type or structure. In three different types of landscape, we surveyed plants, birds, bees, and hover flies on 78 paired fields that either had agri-environment schemes or were managed conventionally, and we collected data on a range of different environmental variables. Neither plant species richness nor abundance of meadow birds was higher on fields with agri-environment schemes. Landscape type had a significant effect on both species groups, but the effects of the schemes were independent of landscape type. Neither the diversity of plants nor the abundance of birds was related to any of the environmental variables. Agri-environment schemes designed to promote plant species richness or bird abundance did have positive side-effects because they enhanced the species richness of bees and hover flies, irrespective of the type of landscape. Furthermore, landscape type, groundwater level (hover flies), and area of wooded edges (bees) significantly affected both species groups. The failure of the schemes to promote the target species may be related to the high intensity of land use in The Netherlands. Simple conservation measures taken by farmers may not be sufficient to counteract the impact of factors that are often controlled at the landscape level (e.g., hydrology). Similar studies in other countries are needed to place the results of our study into a European context.     

Avian Diversity and Functional Insectivory on North-Central Florida Farmlands

Abstract:  We studied the potential for native birds to control insect pests on farms. We assessed habitat factors correlated with diversity, distribution, and insect-foraging activity of native birds on farms in north-central Florida and then characterized common bird species that consumed insect biomass in crops as "functional insectivores" (birds most likely to contribute to pest control). Analyses of point-count survey data and foraging observations collected over 2 years on paired organic and conventional farm sites indicated that (1) farms supported most (82–96%) land birds known to breed in the region; (2) bird species richness and abundance varied significantly with matrix habitat and field border type (but not with year or farm management type); (3) the highest bird abundances were associated with mixed crop plantings, field borders, and adjacent matrix composed of forest and hedge; and (4) abundances of 10 species identified as functional insectivores were primarily influenced by crop type (mixed crops attracted significantly more insect foragers into fields than monocrops). We documented birds eating pest insects in crops and did not observe substantive crop damage by birds during growing-season observations. We advocate use of the term functional insectivore to emphasize the potential positive role of avian insectivory on farms during the growing season.     

广州市白云山雀形目鸟体内汞、砷与硒残留分析

测定了广州市白云山白头鹎(Pycnonotus sinensis)、暗绿绣眼鸟(Zosterops japonicus)、大山雀(Parus major)和白眉鵐(Emberiza tristrami )飞羽、胸肌和肝脏中的汞、砷和硒残留量。汞和砷在鸟体内残留量的分布模式都是,羽毛>肝脏>肌肉;而硒在鸟体内残留量的分布模式是肝脏>肌肉>羽毛,与汞和砷的分布模式不同。鸟组织中的汞质量分数存在种间差异,但不同组织间差异程度不同,白眉鵐肝脏、肌肉中的汞质量分数极显著(或显著)高于暗绿绣眼鸟肝脏、肌肉中的汞质量分数,而2种鸟羽毛中的汞质量分数没有显著差异。鸟组织中砷和硒质量分数的种间差异不明显。羽毛对汞有高的富集作用,用羽毛监测环境中的汞污染比用肝脏和肌肉监测环境中的汞污染更灵敏。在鸟组织中,汞质量分数、砷质量分数和硒质量分数间的相关性较差,只有白眉鵐羽毛中的汞质量分数与硒质量分数存在显著相关性,其回归方程为Y汞=0.657X硒-0.237(p=0.025)。几个地区鸟组织中汞、砷和硒的质量分数的比较表明,广州市白云山受重金属和硒污染程度较低。     

山东资源鸟类及其保护利用

本文对山东省资源鸟类现状及其开发利用途径进行了初步的研究。山东资源鸟类丰富，可分为狩猎鸟、农林益鸟、观赏鸟和珍稀保护鸟。