A possible discrepancy between the exposed and the whole population depending on range-size and trap-spacing in vole populations

Population Ecology - From a field study for the vole population (Clethrionomys rufocanus) in Hokkaido in the late summer of 1965, it has been proved that the range length may decrease from 25 to 18...     

Principles of nonlinear regression modeling

Summary Five principles govern the selection of nonlinear regression models for bacterial growth. Examples are given of the various ways in which researchers have approached the problems of nonlinear regression modeling together with some discussion of linear modeling.Reference to a brand or firm name does not constitute endorsement by the US Department of Agriculture over others of a similar nature not mentioned.     

气候变化导致青藏高原马鹿种群适应性分布退缩：以类乌齐马鹿国家级自然保护区为例

近50年青藏高原的气候变化速率是全球平均值的2倍,对高原有蹄类的种群分布和多样性维持带来严重影响。本研究以西藏类乌齐马鹿国家级自然保护区的马鹿种群为例,通过2013年和2021年对马鹿和牦牛种群数量、分布的调查,并整合了物种分布模型和种群动态模型,评估了当前和未来气候变化及人类活动(放牧、道路、居民点等)对马鹿种群适应性分布的影响。研究表明,马鹿种群在2013—2021年由890头增加到1 400头,根据种群增长模型预计在2050年马鹿种群数量将达到1 735头,但其适宜栖息地在2050年代下降43.4%,2070年代下降5.1%,表明马鹿种群增长与适宜栖息地缩小之间的冲突将不利于马鹿种群的可持续发展。同时,当前马鹿与牦牛栖息地重合率为19%,2050年代为60%,2070年代为37%,且牦牛与马鹿存在食物竞争,这在一定程度上减少了马鹿原有的适宜栖息地。为保护马鹿,建议减少牦牛的饲养量1 000～1 500头。本研究将种群增长模型、种间竞争关系与物种分布模型整合,把气候变化对物种的影响延伸到种群层面,对其他物种的保护具有借鉴意义。     

Biology and Host Range of the Green-seed Weevil, Sibinia fastigiata , for Biological Control of Mimosa pigra

Aspects of the biology and host range of Sibinia fastigiata Clark (Coleoptera: Curculionidae) were studied to assess its safety for release in Australia as a biological control agent of the weed Mimosa pigra L . (Mimosaceae) . Larvae feed on the seeds and adults on open flowers of their host . Adults oviposit on to immature seeds 3 mm long or less and hence seeds of this length and maturity were used in the host range tests and for rearing . Females are shown to avoid previously attacked seeds enhancing their effectiveness as seed destroyers . Survival of adults was higher when provided with open flowers . The host range was determined using laboratory control - choice oviposition tests on excised plant material and , in the field in the native range , no - choice oviposition tests on living plants , surveys of adults on plants , and breeding of insects from pods of plants of various legume species . The control - choice oviposition tests employed a new design in which the control plant alone was offered to the insects followed by a choice of test plants species . Other than M. pigra, only one plant species was acceptable for oviposition , the closely related M. asperata. Larval development also occurs on M. asperata and this host is occasionally used in the field . This insect was approved for release in March 1997 .     

Of mice and wrens: the relation between abundance and geographic range size in British mammals and birds

We examine the relation between population size and geographic range size for British breeding birds and mammals. As for most other assemblages studied, a strong positive interspecific correlation is found in both taxa. The relation is also recovered once the phylogenetic relatedness of species has been controlled for using an evolutionary comparative method. The slope of the relation is steeper for birds than for mammals, but this is due in large part to two species of mammals that have much higher population sizes than expected from their small geographic ranges. These outlying mammal species are the only ones in Britain to be found only on small offshore islands, and so may be exhibiting density compensation effects. With them excluded, the slope of the abundance–range size relation for mammals is not significantly different to that for birds. However, the elevation of the relation is higher for mammals than for birds, indicating that mammals are approximately 30 times more abundant than birds of equivalent geographic range size. An earlier study of these assemblages showed that, for a given body mass, bats had abundances more similar to birds than to non-volant mammals, suggesting that the difference in abundance between mammals and birds might be due to constraints of flight. Our analyses show that the abundance–range size relation for bats is not different for that from other mammals, and that the anomalously low abundance of bats for their body mass may result because they have smaller than expected geographic extents for their size. Other reasons why birds and mammals might have different elevations for the relation between population size and geographic range size are discussed, together with possible reasons for why the slopes of these relations might be similar.     

南岭植物区系地理学研究──Ⅲ．植物区系地理亲缘与区划

南岭山地与相邻地区植物区系具有明显的过渡或替代关系,主要通过亚热带及亚热带亚热带亚洲分布成分与华南南亚热带及亚洲热带地区联系;与华中和华东地区植物区系的联系以亚热带及亚热带至温带分布和中国—日本间断分布成分来沟通;与西南地区植物区系的联系则表现为两地共有的古老和与遗成分区及石灰岩山地区系成分．华夏植物区系,是从古老的华夏植物群逐步发展起来的统一体,在区系分区上应划归为统一的华夏植物界,下分东亚植物区、马来西亚植物区和印度—喜马拉雅植物区。南岭山地植物区系拥有其自身的标志种、特有属和丰富的特有种,在区系分区上可划为完整的南岭植物亚省,下分东南岭植物县、中南岭植物县和西南岭植物县。     

“Australopithecus afarensis”: A composite species

In response to a critique byFerguson (1989),Leonard (1991) reiterates most of his original arguments for supporting “Australopithecus afarensis”Johanson, White, andCoppens, 1978 as a single species. He disregards the principle of morphological equivalence by comparing the dental metrics and morphology of a hominid with those of species of the Pongidae, which do not correspond with the degree of variation in hominids, instead of with those of species of the Hominidae. He fails to refute clear evidence that the range of variation of dental metrics and morphology in “A. afarensis” exceeds that seen in species of the Hominidae. On the basis of extreme variation, “A. afarensis” is, therefore, interpreted as representing a composite species.     

Lower lethal temperatures for fourteen non-native fishes in Florida

Synopsis The most important factor affecting the potential range of 14 non-native fishes in Florida appears to be their lack of tolerance to low temperatures. In this study, temperatures associated with reduction in feeding, cessation of feeding, loss of equilibrium and death were identified by decreasing water temperature 1°C day^–1. Fishes tested and their mean lower lethal temperatures were: Astronotus ocellatus (12.9°C), Belonesox belizanus (9.7°C), Cichlasoma bimaculatum (8.9°C), C. cyanoguttatum (5.0°C), C. meeki (10.3°C), C. octofasciatum (8.0°C), C. trimaculatum (10.9°C), Clarias batrachus (9.8°C), Hemichromis bimaculatus (9.5°C), Hypostomus sp. (11.2°C), Tilapia aurea (6.2°C), T. mariae (11.2°C), T. melanotheron (10.3°C) and T. mossambica (9.5°C). These data indicate that temperature is less limiting for these fishes in Florida than was previously recognized.Contribution Number 18, Non-Native Fish Research Laboratory, Florida Game and Fresh Water Fish Commmission, 801 N. W. 40th Street, Boca Raton, FL 33431, U.S.A.     

Small and overlooked: Phylogeny of the genus Trigonodactylus (Squamata: Gekkonidae), with the first record of Trigonodactylus arabicus from Jordan

Geckos of the genus Trigonodactylus are widely distributed in the sand deserts of the Arabian Peninsula. Three species of this genus are currently recognized, with a fourth one, Stenodactylus pulcher, which placement within Trigonodactylus has been tentatively suggested, but not yet confirmed. We present a phylogenetic analysis of the genus Trigonodactylus with new specimens collected in central Saudi Arabia and southern Jordan. New genetic data has been generated from three mitochondrial markers to investigate the phylogenetic relationships of all species of the genus and to assess the putative generic assignment of S. pulcher. Our results confirm that S. pulcher indeed belongs within Trigonodactylus, branching as a sister lineage to all other species of the genus. The new samples cluster within Trigonodactylus arabicus, thus confirming the genetic homogeneity of the species across its large and seemingly inhospitable range. The new specimen collected in southern Jordan represents the first record for the country and a considerable range extension to the northwest from all previously reported localities. Our findings and discovery of a new species for Jordan highlight the need of more field surveys to be carried out in the underexplored parts of Jordan and northern Saudi Arabia, as these places still hold a potential for new discoveries and are crucial for understating the biogeography of the Arabian herpetofauna.