Continuity and discontinuity of the riparian vegetation along a fluvial corridor

The concept of continuity/discontinuity is applied to the riparian vegetation of the corridor of the River Adour (S.W. France), in order to precisely define longitudinal structure, and to test the degree of floristic continuity of the fluvial axis. The measure of floristic connectance along the river course is based on presence/absence data, and is applied to successive stretches of the river, at various resolution levels. This analysis shows that the River Adour corridor cannot be assumed to be floristically continuous. The observed discontinuities may correspond to two types of change in the riparian vegetation: zones of slow change (high level of floristic connectance) or zones of sharp change (low level of floristic connectance).     

Can place names be used as indicators of landscape changes? Application to the Doñana Natural Park (Spain)

This work broaches the possibility of using place names as indicators of original landscapes that have been much transformed. The reconstruction of landscape elements from place names is commonly disputed because such daring notion is impossible to demonstrate. The present case avoids this by making a preliminary study of changes in the landscape using conventional methods. With the knowledge gained from objective and reliable sources, the possibility is analyzed of whether place names are a reflection of landscape changes taking place over a considerable period of time (the last few centuries). It is concluded that, for the present case study, in natural areas with a high rate of change of land use (Doñana Natural Park), place names indicate not only changes in the landscape, but also how such changes are perceived. In the study area, this is especially clear regarding the fens.     

Changes in a remnant of salmon gum Eucalyptus salmonophloia and York gum E. loxophleba woodland, 1978 to 1997. Implications for woodland conservation in the wheat-sheep regions of Australia

The condition of salmon gums Eucalyptus salmonophloia with large hollows in them in a 15-ha patch of remnant salmon gum-York gum E. loxophleba woodland in the northern wheatbelt of Western Australia was examined in 1978. The patch was an important breeding area for six species of cockatoo, including two endangered species. The patch was revisited in 1981 when the condition of all 682 salmon gums and York gums in the patch was examined and each was measured and photographed. A further visit was made in 1997 when the condition of the surviving trees was examined and each was again measured and photographed. The condition of the trees at each visit was classified as “good”, “staghorn”, “broken top”, “dead” or “fallen.” Over the period of the study there was a serious decline in the condition of the trees, with few large trees in the “good” category by 1997. The decline was particularly marked between 1978 and 1981 after a period of well-below average annual rainfall. Using data based on the rate of decline over the period 1978-1997, predictions were made of the fate of the trees in the patch. By 2125 only 46 (11% of the 1981 total) salmon gums were predicted to be alive with only one in the “good” category. Only 16 (17%) York gums were predicted to be alive by 2125, with only one in the “good” category. There was no evidence of any regeneration of woodland trees since 1929 when the patch was isolated by clearing for agriculture, and domestic livestock allowed to graze the patch. This deterioration of the dominant trees in the patch is symptomatic of remnant native vegetation over vast areas of Australia's extensively cleared wheat-sheep regions. The future of woodland patches like the one studied is bleak, as is the future of animals dependent on them for food, breeding sites and shelter. Active management, including fencing to exclude domestic livestock and measures to encourage regeneration of native plant communities, is necessary to counter the present regime of benign neglect that characterises most of Australia's management of native vegetation in agricultural landscapes.     

The phylogeographic system survey of native sheep breeds in the eastern and southern Central Asia

The genetic diversity and phylogenetic survey of native sheep breeds in the eastern and southern Central Asia were assessed in the present study. The clustering, principal components, structure and F statistics all demonstrate that the native sheep breeds in these regions be classified into two genetic groups: Mongolia‐Tibetan sheep group and South‐Southeast Asia sheep group. The Mongolia sheep group and the Tibetan sheep group had a certain degree of gene communication from the ancient times. In the present study we demonstrated that the Chinese native sheep populations belonged to Mongolia‐Tibetan sheep group. However, the relationships among the sheep populations in Mongolia sheep group in China were not closely related to the geographical distance among sheep populations.     

北京九龙山森林植被涵养水源效能多层次模糊综合评判

运用多层次模糊综合评判模型，对北京九龙山主要４种森林植被类型涵养水源效能进行了综合评判，结果表明，油松林水源涵养综合效益最好，其次为阴坡灌木林和侧柏林，阳坡灌木要最次，并据此分析该４种类型的经营，保护和利用措施，讨论了该模型在应用过程中的一些特点。     

杭州非栽培植物上访花蓟马种类调查及发生分析

为明确蓟马在野外不同植被上的发生动态,了解不同蓟马的寄主偏好性。从4月中旬至11月中旬,每2周对杭州茅家埠多种植物花上的蓟马种类进行采集并在室内进行种类鉴定,并且对几种主要植物的几种蓟马种群动态进行分析,包括对金丝桃Hypericum chinese花上的花蓟马Frankliniella intonsa、西花蓟马F.occidentalis、黄胸蓟马Thrips hawaiiensis及黄蓟马T.flavus;一年篷Erigeron annuus花上的花蓟马、西花蓟马、小头蓟马Microcephalothrips sp;空心莲子草Alternanthera philoxeroides花上的花蓟马、西花蓟马及黄胸蓟马及美人蕉Canna indica花上的花蓟马、黄胸蓟马、黄蓟马及茶黄硬蓟马Scirtothrips dorsalis发生进行分析。调查发现蓟马种类分属6属16种,其中花蓟马、黄胸蓟马及黄蓟马是该地主要的蓟马种类。分析发现,金丝桃上花蓟马是优势种,其他几种只是偶尔发生,一年篷上优势种是小头蓟马并且发生量在开花的后期较多,即在整个7月,空心莲子草上蓟马的数量在开花的早期较多,从6月初至7月初,后期减少明显,主要是花蓟马和西花蓟马两种,美人蕉上主要的蓟马种类是黄蓟马和黄胸蓟马,在整个开花期,有3个发生高峰期,分别为7月上中旬,9月中下旬及11月上中旬,并且种群发生量大,最高时达到每花101.60±13.89头。同时花蓟马的数量也较高,最高时每花达12.60±4.35头,因此从上述的分析发现,花蓟马的适宜寄主范围广,除一年篷花上较少外,其他3种植物的花上都较多,这3种植物都可作为花蓟马的虫源地,黄蓟马和黄胸蓟马的主要适宜寄主为美人蕉花,西花蓟马则在空心莲子草上发生较多,而小头蓟马的适宜寄主则是一年篷。