High-resolution climatic analysis and southwest biogeography

Meteorologists and climatologists have produced significant new data on the fluid dynamics of the atmosphere, thus allowing biologists to examine more closely the cause-effect relation between the large-scale structure of the atmosphere and the dominant patterns of global biogeography. The inability to characterize the high-frequency variability of the weather has constrained such efforts. A method that allows year-to-year patterns of weather variability to be characterized in the contexts of global warming and cooling trends is applied in a combined analysis of long-term monthly weather records and data from an ecological monitoring project in southern New Mexico. The analysis suggests a cause-effect hypothesis of recent desertification in the North American Southwest. The links between the atmosphere and the biosphere are based on the fundamentally different responses to specific weather regimes of semidesert grasses with a C(4) photosynthetic pathway and desert shrubs with a C(3) photosynthetic pathway. The hypothesis appears to be of sufficient generality to explain the complex, but well-documented, floristic changes that have occurred in the same region since the last glacial maximum.     

Island biogeography theory and conservation practice

The application of island biogeography theory to conservation practice is premature. Theoretically and empirically, a major conclusion of such applications-that refuges should always consist of the largest possible single area-can be incorrect under a variety of biologically feasible conditions. The cost and irreversibility of large-scale conservation programs demand a prudent approach to the application of an insufficiently validated theory.     

Evolution and biogeography of deep-sea vent and seep invertebrates

Deep-sea hydrothermal vents and cold seeps are submarine springs where nutrient-rich fluids emanate from the sea floor. Vent and seep ecosystems occur in a variety of geological settings throughout the global ocean and support food webs based on chemoautotrophic primary production. Most vent and seep invertebrates arrive at suitable habitats as larvae dispersed by deep-ocean currents. The recent evolution of many vent and seep invertebrate species (<100 million years ago) suggests that Cenozoic tectonic history and oceanic circulation patterns have been important in defining contemporary biogeographic patterns.     

Barrier island configuration

The 11 Virginia barrier islands are undergoing rapid changes in shore-line configuration. If this trend continues for another 100 years, two capelike features will develop. The process responsible for this island-chain pattern may be a standing edge wave trapped between Assateague Island and Cape Charles.     

浅谈生物地理学及替代分化生物地理学

生物地理学是研究特定的时间范围内生物空间分布的科学。它的目标在于解释动植物的结构、功能和历史与生物分布的关系，以及这种关系与种系发生的相关性。本文简述了生物地理学研究的历史，综合分析了各学派论点及其异同，并对替代分化生物地理学的基本观点、研究方法作了较详尽的论述。     

Microbial biogeography: from taxonomy to traits

The biogeographic variation of life has predominantly been studied using taxonomy, but this focus is changing. There is a resurging interest in understanding patterns in the distribution not only of taxa but also of the traits those taxa possess. Patterns of trait variation shed light on fundamental questions in biology, including why organisms live where they do and how they will respond to environmental change. Technological advances such as environmental genomics place microbial ecology in a unique position to move trait-based biogeography forward. We anticipate that as trait-based biogeography continues to evolve, micro- and macroorganisms will be studied in concert, establishing a science that is informed by and relevant to all domains of life.     

棉花内生细菌的分离及生防益菌的筛选

对不同品种和不同种植地区的健康棉花植株组织中内生细菌进行分离,共得到102个菌株.经鉴定分属于芽孢杆菌属(Bacillus sp.)、黄单孢菌属(Xanthomonas sp.)、假单孢菌属(Pseudomonas sp.)、欧文氏菌属(Erwinia sp.)及短小杆菌属(Curtobacterium sp.),其中芽孢杆菌的分离频率最高,为优势种群.对内生细菌数量测定表明,棉花种子、根、茎、叶柄、叶片等组织内均存在大量的内生细菌.不同品种、组织及种植地,内生细菌的数量不同.各组织中内生细菌的种群密度的分布特点是种子中最多,其次为根,再次为茎,叶片、花蕾,叶柄中最少.从87个棉花内生菌的分离菌株中筛选出对棉花枯萎病菌有体外拮抗活性的菌株22个,占菌株总数的25;;15株对立枯丝核菌有抑制作用,占菌株总数的17;.15株对两种病原菌都有抑菌作用,其中有些菌株表现出较强抑菌活性,具有作为生防菌的潜能.