杉木球果麦蛾种群动态规律的研究

杉木球果麦蛾是杉木的主要种实害虫，其危害可造成种子品质和产量的严重下降。据４个年份的调查结果表明，杉木球果麦蛾幼虫种群数量变动比较稳定。每样枝平均虫口密度在０．２５─２．５条内变动。因幼虫在球果内栖息和危害受外界气候、天敌等影响小，故存活率较高：根据４年的观察比较，平均存活率８５．８％。可以此作为参数，准确预报翌年的种群消长趋势，为生产上开展综合治理提供科学依据。     

Study on Cultivation Nutrition of Cunninghamia lanceolata Plantations with Multi-generation Management

Based on the previous study on cultivation nutrition of Cunninghamia lanceolata plantations of first generation, the cultivation nutrition of C. lanceolata plantations with multi-generation was studied. The results show that there are significant differences in the growth, development and nutrient assimilation among C. lanceolata plantations with different generations and nutrition conditions. These differences are closely related to the land fertility decline of C. lanceolata plantations. This paper demonstrates the mechanism of land fertility decline caused by successively planted C. lanceolata plantations, and provides the directions to work out proper nurture practices and management measures to keep land fertility from declining.     

Relationships between health of Quercus robur, occurrence of Phytophthora species and site conditions in southern Sweden

The effect of Phytophthora species, soil chemistry, precipitation and temperature on the vitality of oak was evaluated in 32 oak stands in southern Sweden. In addition, the relationship between the occurrence of Phytophthora species and soil conditions was determined. The results showed that there was a weak association between the presence of P. quercina , the most frequently recovered Phytophthora species in southern Sweden, and the vitality of the oak stands (determined from estimates of crown defoliation of individual trees). The pathogens occurred more frequently in clayey and loamy soils that were less acidic and which had higher base saturation. However, they were found in all but the most acidic soils (pH < 3·5). In stands where Phytophthora species were not present, positive correlations between the average crown defoliation and proportion of damaged trees with average summer precipitation and average annual precipitation were found. There were no significant differences in soil chemistry between healthy and declining stands included in this study, and no significant correlations were found between any soil parameter and crown vitality. Based on the results from these 32 oak stands, it is likely that the decline of oaks in southern Sweden can be attributed to several different site-specific factors, such as infection by P. quercina or unusual weather events, which interact with a number of biotic and abiotic factors, leading to oak decline.     

Spatial sensitivity of species habitat patterns to scenarios of land use change (Switzerland)

Long-term societal trends which include decreasing population in structurally poorer regions and changes in agricultural policies have been leading to land abandonment in various regions of Europe. One of the consequences of this development includes spontaneous forest regeneration of formerly open-land habitats with likely significant effects on plant and animal diversity. We assess potential effects of agricultural decline in Switzerland (41,000 km²) and potential impacts on the spatial distribution of seven open-land species (insects, reptile, birds) under land-use change scenarios: (1) a business-as-usual scenario that extrapolates trends observed during the last 15 years into the future, (2) a liberalisation scenario with limited regulation, and (3) a lowered agricultural production scenario fostering conservation. All scenarios were developed in collaboration with socio-economists. Results show that spontaneous reforestation is potentially minor in the lowlands since combinations of socio-economic (better accessibility), topographic (less steep slopes), and climatic factors (longer growing seasons) favour agricultural use and make land abandonment less likely. Land abandonment, spontaneous reforestation, and subsequent loss of open-land, however, are potentially pronounced in mountainous areas except where tourism is a major source of income. Here, socio-economic and natural conditions for cultivation are more difficult, leading to higher abandonment and thus reforestation likelihood. Evaluations for open-land species core habitats indicate pronounced spatial segregation of expected landscape change. Habitat losses (up to 59%) are observed throughout the country, particularly at high elevation sites in the Northern Alps. Habitat gains under the lowered agricultural production scenario range between 12 and 41% and are primarily observed for the Plateau and the Northern Alps.     

甘蓝型油菜雄性不育系微量花粉消长动态研究初报

微粉数量在不同不育系之间、不同播期之间、不同开花时期之间存在显著或极显著差异。随着播期推迟，不育系的微粉下降速率不同，以华油1087的微粉下降速度最快。秦油2号和郑杂4号的微粉量较多，与开花前0℃以上的积温之间存在极显著的正相关。     

Population decline of Macaca sylvanus in the middle atlas of Morocco

An eight-year-long census and habitat evaluation of the Macaca sylvanus population was conducted in a 484-km² area of the central region of the Middle Atlas Mountains in Morocco between June 1994 and October 2002. The authors walked a 93.5-km circuit - divided into 16 transect segments - 30 times with teams of trained research assistant volunteers, collecting data on a total of 2,805 linear km. Previous studies had reported an average density of 44-70 individuals per km², while data from the present study indicate a progressive population decline, from 25 to 30 individuals per km², down to a current average density of 7-10 I/km². The population decline is attributed to the loss of prime habitat, mainly cedar forest, which has significantly decreased from 1994 to 2002, due to the growing impact of overgrazing by mixed flocks of goats and sheep and consequent forest degradation. At present, human-caused habitat deterioration in the Middle Atlas risks further compromising the future of the world’s only remaining large M. sylvanus population.     

工厂化番茄秧苗运贮中质量下降信号物质变化的模拟试验

采用测定信号物质含量方法进行番茄秧苗模拟运贮试验，结果表明：模拟运贮期间的“断光”“断水”使得番茄秧苗的信号物质含量发生明显而定向的变化，即使植物衰变的胞间信号脱落酸和内源乙烯含量在运贮过程中急剧上升；同时，参与植物合成代谢的胞内信号钙调素(CaM)及NAD激酶的活性同步下降，最终导致产生“胁变性生理衰变”，使得运贮以后秧苗的正常生长代谢受到抑制，运贮中信号系统的定向变化是发生 “胁变性生理衰变”进而导致其质量下降的内在因素，至此, 运贮期间番茄秧苗质量下降的信号系统已经基本明确。这方面研究为完善蔬菜生产产业化技术体系尤其是揭示工厂化番茄秧苗运贮中质量下降的机理提供了理论依据。     

Rapid diversity and abundance decline in a Caribbean coral reef sponge community

Sponges are abundant and diverse on coral reefs, and play key functional roles; but virtually nothing is known of their dynamics. This is the first report of coral reef sponge community dynamics documented by a series of censuses in which volume and species of every individual were recorded. At the start of the 14 year study, there were 1395 sponge individuals, representing 39 species in nine orders, and a total sponge volume of 33,721 cm³ in the censused area of a shallow Caribbean reef in San Blas, Panama. The most striking results of the 5 censuses were steady disappearance of species (51.3%) throughout the study period, and a steep drop in total sponge volume (42.6%). Species in keratose orders and with massive growth forms were lost disproportionately. Sponge losses could not be attributed to predators, physical disturbance (including a hurricane), extreme episodes of other abiotic factors, or disproportionately great loss of rare species due to random fluctuations. Disease may have played a role.High loss rates documented at this and nearby sites could be a local phenomenon, but scattered reports of disease and mass mortality of sponges from other sites suggest these data may reflect region-wide losses. Monitoring programs designed for corals and mobile unitary organisms can miss changes in sponges because very high sponge species diversity, facile fragmentation and fusion, and quick and complete disappearance of dead sponges, impedes perception of changes if there are no prior censuses. Whether or not sponge declines are extensive will remain unknown until repeat censuses have been accomplished at additional sites. Sponges can increase water clarity, bind live corals to the reef frame, and facilitate reef regeneration, suggesting that loss of sponges could accelerate declines of coral reefs.     

Bird-habitat relationship for the declining Pampas meadowlark populations in the southern Pampas grasslands

During the past century, the Pampas meadowlark Sturnella defilippii underwent a severe population drop and now, it is confined mostly to southern Pampas grasslands. We analyzed the habitat and landscape characteristics associated to the presence of reproductive groups of Pampas meadowlarks in this area. During the 1999 breeding season, we surveyed 89 randomly stratified selected points where we noted the presence/absence of Pampas meadowlarks. For each point we estimated seven habitat variables related to vegetation cover and six landscape variables derived from different maps. We found 11 groups of displaying males, nine of them on natural grassland plots. Multivariate analyses indicate that field type and vegetation cover are the main factors associated to the presence of Pampas meadowlark. Reproductive groups were found preferentially at natural grasslands with high vegetation cover. Habitat loss and intensive grazing of fields appear to be the main factors associated to their sharp population decline and distribution retraction.     

Declines of the gopher tortoise on protected lands

We compared two assessments of the status of gopher tortoise populations at 10 protected sites in Florida, taken about a decade apart. We assessed status indirectly, using surveys of burrows along belt transects. Transect placement and timing were identical between surveys. We compared numbers of burrows, relative numbers of burrows of different activity conditions, and size distributions of burrows between surveys. The comparisons indicated that populations had declined at as many as eight of the sites. We found no strong connection between population decline and decline in habitat quality, as reflected in decreased ground cover and/or increased canopy cover between surveys. The response of a population to decline in habitat quality may depend on initial habitat structure, the degree of change in habitat structure, the period of time over which change is measured, the amount of habitat involved, and the level of habitat management.