金佛山自然保护区外来入侵植物种及其分布情况

生物入侵对全球的生物多样性造成了严重威胁。自然保护区是保护生物多样性的重要基地,因此,自然保护区的生物入侵现状如何备受关注。本研究以金佛山国家一级自然保护区为研究区域,采用样方法和野外踏勘法对金佛山自然保护区的外来植物进行了调查,初步调查结果如下:1)在金佛山共发现56种外来植物种,主要是草本类植物,且多呈零星分布,绝大部分外来植物与本地植物一样仅仅作为一种可利用资源出现,而且没有出现明显的相互竞争,但五节芒具有突出的入侵分布特征;2)56种外来植物中有31种是有意引进的,占入侵种总数的55%;15种是自然入侵的,占27%;有9种是入侵来源不明的,占16%;1种是伴随其他物种无意引进的,占2%。而目前危害面积最大的五节芒就是入侵通道不明的外来植物种;3)调查的样方中外来植物的出现频度与干扰程度相关,干扰越严重的,出现外来植物种的几率越大,踏勘也呈现了同样的规律。     

Critical Care of the Exotic Companion Mammal (With a Focus on Herbivorous Species): The First Twenty-Four Hours

The number of pet herbivorous exotic mammals is increasing, and their owners are demanding quality medical care. Successful treatment of the critical herbivorous exotic mammal patient is complicated by small patient size, physiological diversity, and a lack of research and clinical data regarding therapeutic response to disease conditions. Despite these impediments, the same principles and techniques used in other domestic animals, such as dogs and cats, can be applied to the herbivorous exotic mammal patient.     

Educating the exotic animal technician.

The thorough education of a skilled exotic animal technician is an ongoing process. Providing the educational tools is only the beginning. Building on the initial educational groundwork is required to excel. Veterinary technicians interested in exotic animal medicine must lobby to promote awareness of the demand for exotic pet care; be able to accept, adapt, and apply new data frequently; and receive constant support and encouragement from the exotic animal veterinarian.     

Critical care monitoring.

Critical care monitoring in exotic practice is limited by the small size and the physiologic diversity of many patients. However, many of the principles applied to humans and other mammals can be extrapolated to monitoring in exotic animals. Advances in the monitoring of human patients offer the potential for more practical, low-cost monitoring in critical exotic patients in the future.     

Fuel Reduction,Seeding, and Vegetation in a Juniper Woodland

Western juniper has increased in density and distribution in the interior Pacific Northwest since the late 1800s. Management goals for many juniper woodlands are now focused on reducing tree densities and promoting biodiversity, prompting the use of fuel reduction treatments. Fuel reduction often involves mechanical cutting and disturbances such as slash pile burning and skid trail formation. While these activities may reduce tree densities, the extent to which they will restore native biodiversity and community composition, particularly in woodlands invaded by exotic annual grasses, is unclear. We evaluated the effects of juniper cutting in two experiments of disturbance type (slash piles and skid trails) followed by three native seeding treatments (cultivar, locally sourced, and no seed) on vegetation in central Oregon. Prior to cutting, native perennial grass cover and richness were positively associated and exotic grass cover was negatively associated with juniper basal area. After cutting and 2 yr after seeding, species composition was altered for both disturbance types. Some seeded areas had higher total species richness, higher native species richness, higher cover of seeded species, and higher overall cover compared to areas that were not seeded. But seeding effectiveness in mitigating exotic species spread varied based on exotic species functional group, pretreatment propagule pressure, and experiment disturbance type. Neither seed mix lowered exotic grass cover. There was limited evidence that the cultivar mix outperformed the locally sourced native seed mix. In the short term, fuel reduction activities may have facilitated further conversion of this woodland to an exotic grassland, but longer-term evaluation is needed. In juniper woodlands that have been invaded by exotic species, fuel reduction activities may facilitate further invasion, and exotic species control may be needed to limit invasion and promote native vegetation.     

加拿大一枝黄花研究进展

外来植物的引入或入侵,对我国农林牧业已经产生了惊人的直接经济损失,它们引起生态系统紊乱、生物多样性的丧失而造成的间接经济损失更是无法估计。外来植物入侵已成为生物多样性保护和生态系统恢复研究的热点问题,对外来种的入侵理论,即入侵生态学的研究也正在兴起。通过从外来入侵植物加拿大一枝黄花的生物学特性、对环境条件的适应性、对植物多样性的危害、药用价值及防治方法等方面进行了综述。     

Interactive Effects of Nitrogen Deposition and Grazing on Plant Species Composition in a Serpentine Grassland

The interaction of resource availability and disturbance can strongly affect plant species richness and the spread of exotic plants. Several ecological theories posit that disturbance mediates the richness-reducing effects of increased competition as resource levels rise. In the low-nutrient serpentine grasslands of the San Francisco Bay Area, the fertilizing effects of atmospheric nitrogen (N) deposition may threaten native species by promoting nitrophilic exotic grasses. Attempts to mitigate these N deposition effects have focused on cattle grazing as a strategy to reduce exotic grass cover. We simulated realistic N deposition increases with low-level fertilization, manipulated grazing with fencing, and monitored grazing intensity using camera traps in a 4 yr factorial experiment to assess the effects of grazing and N deposition on several measures of native and exotic species dynamics in California's largest serpentine grassland. Our results suggest that native species diversity may increase slightly under low-level N deposition with moderate grazing in this system. However, grazing may not be effective at limiting exotic cover as N accumulates in the future. Examination of treatment trajectories using principal response curves indicated that responses to grazing might be determined more by functional group (forb or grass) than origin (native or exotic). Grazing intensity varied dramatically within the single stocking rate used to manage this ecosystem. Given this variation and the contrasting effects of grazing on different functional groups, more targeted management may be required to improve conservation outcomes.     

Emergency Presentations of the Exotic Small Mammalian Herbivore Trauma Patient

Trauma is a common complaint by owners of small exotic mammalian herbivores (e.g., rabbits, rodents) presented to veterinary hospitals. The term “trauma” is a broad disease category applied to patients with physical debilitation associated with injury often classified as “blunt,” “penetrating,” or “burn” in origin. Because many small exotic mammalian herbivores are prey animals, clinical signs of trauma may be masked until the effects of the injury outweigh the innate nature to survive. Small exotic mammalian herbivores are disproportionately sensitive to stress; thus, pain management and supportive care are extremely important during the initial stages of trauma management. Small exotic mammals differ slightly from other companion animals (e.g., dogs, cats) in regard to common trauma presentations. However, with a few therapeutic modifications (e.g., antibiotic selection, avoidance of corticosteroids, preventing self-trauma), treatment of small exotic mammalian herbivore trauma cases follows the same conventional guidelines used for other companion animals.     

Clinical nutrition of exotic pets

SUMMARY Successful nutritional management requires knowledge of the natural history of exotic pets, nutrient contents of foods, and roles of water, calories, and nutrients in optimal health. Unestablished dietary requirements, lack of balanced commercial diets and mismanagement by owners cause nutritional problems that affect health and recovery from illness and trauma. When presented with a sick exotic pet, veterinarians should check for provision of appropriate wholesome water and food in optimal amounts. Malnutrition and dehydration are common in exotic pets and often result from mismanagement. Starvation is common in carnivores eating whole vertebrate prey, whereas specific nutrient deficiencies are more common in herbivores and insectivores. The more common nutritional deficiencies are calcium and vitamin D₃, vitamin A, thiamin, and vitamin E. When treating sick exotic pets, nutrition and fluid support may be critical to recovery.     

Exotic Plant Species Diversity: Influence of Roads and Prescribed Fire in Arizona Ponderosa Pine Forests

Many studies have investigated the ecological effects of roads and roadsides as both habitat and dispersal corridors for exotic plant species. Several of these compared roadside exotic species richness and abundance with adjacent interior habitats, but we found no studies of individual exotic species’ abundance between the two habitats in the context of prescribed fire. We measured exotic species richness and individual species’ abundance along roadsides and in adjacent interior habitat (> 150 m) before and after prescribed fire at three ponderosa pine (Pinus ponderosa Douglas ex Lawson & C. Lawson) sites in northern Arizona. Eighteen of the 20 exotic plant species found in this study have been and continue to be intentionally introduced or are known agricultural seed contaminants. Roadsides had significantly higher exotic species richness than adjacent forest interior habitats, but only one site showed a significant (decreasing) fire effect on species richness. Four exotic plant species had significantly higher densities along roadsides at two of the three sites, and four species had no significant difference in abundance between habitats at any site supporting an individualistic species response hypothesis. Most exotic species showed no significant change in density post-prescribed fire suggesting that low-intensity prescribed fire may have minimal effect on exotic species diversity. Variability in total exotic species richness, composition, species’ constancies, and species’ densities between the three regionally similar sites suggests differing degrees and effectiveness of past management practices and policies such as intentional seeding.     

Skin diseases of rodents and small exotic mammals.

Small exotic mammals and rodents are becoming popular pets in the United States. Like most other exotics, the popularity of these animals has vastly preceded the accumulation of practical husbandry and veterinary information available about them. Several dermatologic conditions have been described in most rodents and small exotic mammals; however, the practitioner can assume that more exist that have not yet been diagnosed or documented. It is not unreasonable to assume that rodents and small exotic mammals could be affected by many of the same dermatologic conditions well described in other animals. Veterinarians are encouraged always to apply the same diagnostic protocols used to work up skin problems in dogs and cats when presented with an exotic pet with a dermatologic disease.     

The leaf-litter earthworm fauna (Annelida: Oligochaeta) of forests in Limpopo Province,South Africa: diversity,communities and conservation

A qualitative survey of the leaf-litter earthworm fauna of 11 selected indigenous forests in Limpopo Province, South Africa, was conducted to identify the species present, to describe the communities and to assess the relationship between indigenous and exotic species. A total of 8185 individuals from 17 species (five indigenous and 12 exotic species) were recorded. The average earthworm community comprised fewer than five species, but up to seven species were sampled from a single forest. Four of the species recorded are national (one species), regional (one species) or local (two species) endemics. Because these species are not known to live elsewhere, the protection of Limpopo Province forests is critical to their survival. The majority (71%) of the earthworm species sampled was exotic, and differences between exotic and indigenous species richness in forests were mostly significant. At the two spatial scales examined (20 m2 and individual forest) there is no evidence of an association between exotic and indigenous species richness. However, we cannot assume that exotic earthworms do not impact the forest ecosystem.     

Comparative studies of gastrointestinal helminths of poultry in Zaria, Nigeria.

Two-hundred and ten digestive tracts of local chickens reared in and around Zaria, Northern Nigeria, under the extensive native free range system of management and 203 digestive tracts of exotic chickens raised under the intensive system of management were examined for parasites. Two hundred and one (95.7%) of the local chickens were infected and 24 (11.8%) of the exotic chickens also. Among the local chickens, 12 species of nematodes and 7 species of cestodes were recovered. Only one nematode and one cestode species were recovered from the exotic chickens. The prevalence of helminth infections between local and exotic chickens was significantly different at 1%.     

蛇岛外来物种入侵现状及生态影响调查

蛇岛是我国唯一一个以蛇岛蝮蛇（Agkistrodon shedaoensis）为主要保护对象的国家级自然保护区,具有重要的科研和生态保护价值,但外来物种入侵已经对该岛生态环境及生物多样性造成严重威胁。本文对蛇岛外来物种的入侵现状进行了野外实地调查,并对其入侵途径、危害特点进行了详细分析。同时,为有效保护蛇岛蝮蛇及蛇岛的生物多样性,提出了控制外来物种入侵的具体建议和对策。     

Histological assessment of puberty in dogs in the Zaria area of northern Nigeria

The ages of puberty and sexual maturity were histologically determined in 300 dogs, comprising 115 local Nigerian dogs and 185 crosses of local with exotic breeds. The ages ranged from six months to eight and a half years. The age at puberty was estimated to be seven to eight months and the age of sexual maturity to be 10 to 11 months for all the dogs, both local and exotic. Testicular and epididymal dimensions and weights, on average, increased progressively from before puberty until sexual maturity. The same trend was observed in the diameters of seminiferous tubules, the percentage of spermatogenesis and the epididymal sperm reserves. At puberty an average of 51.8 per cent of the caudal epididymal sperm cells of the local dogs had morphological defects compared with 54.5 per cent in the exotic cross breeds. The defects were mostly coiled tails and proximal cytoplasmic droplets. These defects had decreased to an average of 12.8 per cent in all breeds by the time the dogs had attained a mean age of one and a half years. In general the post-pubertal pattern of spermatogenesis in the dogs resembled that of the bull, and the ages at onset of puberty and sexual maturity fall within the range determined for exotic breeds of dogs. There were no significant differences between the local Nigerian dogs and the local cross exotic breeds in the parameters studied.     

Breed and sex influences on porcine haematological picture under hot humid climatic conditions

An investigation was undertaken of some haematological characteristics of one indigenous and five exotic breeds of pigs kept on a farm in the hot, humid climate of Ibadan, Nigeria. The total white blood cell counts were not affected by breed and sex but the other parameters exhibited various degrees of response to these two variables, the males of each breed tending to have higher values than the females. The indigenous pigs generally had higher values than the exotic breeds. Of the latter, only the Landrace and Large White had haematological values somewhat similar to those of the West African indigenous pig. This suggests that the Landrace and Large White breeds may be more suited than the other exotic breeds investigated to the climatic conditions prevalent in Ibadan.     

The role of the public sector in the development and implementation of animal health policies.

Although it is widely accepted that both the public and private sectors have a role to play in improving animal health, the debate centers on the balance between the two. The comparative advantages of each sector depend on: (i) whether the targeted disease can affect humans; (ii) its degree of contagiousness; (iii) whether it is endemic or exotic; and (iv) the economic costs associated with the disease. The rationale for public intervention is weaker for non-contagious than for contagious diseases; governments, though, can play a support role in several areas: e.g. generation and dissemination of information on health management, fostering participation of producers' organization in the eradication of endemic diseases, or helping private research institutions and funders to overcome the hurdles posed by widespread uncertainty and high costs associated with basic research. Control and eradication of contagious diseases in characterized by strong externalities; bio-security measures implemented by any producer affect his/her neighbors. A major factor affecting the design of appropriate health policies for contagious diseases is whether the disease is endemic or exotic in a particular population. The externality exists for endemic diseases--but for exotic diseases there is only the possibility of an externality (which materializes solely in the case of an outbreak). For exotic diseases, therefore, the perception of the risk of an outbreak is a major determinant of producers' behavior and of public prevention policies. The perception by producers and policy makers of the probability of occurrence of an outbreak of an exotic disease depends on the time elapsed since the last outbreak in the country or in neighboring countries. In general, perception of the risk of an outbreak will be lower than the true risk for most exotic diseases that have been absent for many years--but might be higher than the true risk if an outbreak was recently reported in the region. Taxes and private insurance have been proposed to internalize the externality; however, these policies cannot solve the health externality. Alternative programs (such as joint public-private eradication campaigns) are proposed as a means to minimize the externality.     

Future directions in training of veterinarians for small exotic mammal medicine: expectations, potential, opportunities, and mandates

Small exotic mammals have been companions to people for almost as long as dogs and cats have been. The challenge for veterinary medicine today is to decipher the tea leaves and determine whether small mammals are fad or transient pets or whether they will still be popular in 20 years. This article focuses on pet small-mammal medicine, as the concerns of the laboratory animal are better known and may differ profoundly from those of a pet. Dozens of species of small exotic mammals are kept as pets. These pet small-mammal species have historically served human purposes other than companionship: for hunting, for their pelts, or for meat. Now, they are common pets. At present, most veterinary schools lack courses in the medical care of these animals. Veterinary students need at least one required class to introduce them to these pets. Currently, there are no small-mammal-only residency programs. This does not correspond with current needs. The only way to judge current needs is by assessing what employers are looking for. In a recent JAVMA classified section, almost 30% of small-animal practices in suburban/urban areas were hiring veterinarians with knowledge of exotic pets. All veterinarians must recognize that pet exotic small mammals have changed the landscape of small-animal medicine. It is a reality that, today, many small-animal practices see pet exotic small mammals on a daily basis.     

The role of indigenous wild, semidomestic, and exotic birds in the epizootiology of velogenic viscerotropic Newcastle disease in southern California, 1972-1973.

During an epornitic of velogenic viscerotropic Newcastle disease (VVND) in southern California, free-flying wild birds, captive and free-ranging semidomestic birds, and exotic birds were collected from the quarantine area to determine their role in the epizootiology of the disease. The VVND virus was isolated from 0.04% of 9,446 free-flying wild birds, 0.76% of 4,367 semidomestic birds, and 1.01% of 3,780 exotic birds examined. Three house sparrows and 1 crow directly associated with infected poultry flocks were the only free-flying wild birds from which VVND virus was isolated. Among semidomestic species, ducks, quail, chukars, pheasants, peafowl, pigeons, and doves were found to be infected. Psttacines, pittas, and toucans accounted for 92% of the VVND virus isolations from exotic birds. In addition, domestic Newcastle disease virus (NDV) was isolated from 0.29% of the free-flying wild birds, from 1.65% of the semidomestic birds, and from 0.19% of the exotic birds collected. Hemagglutination-inhibition against domestic NDV was demonstrated in 0.24% of 3,796 wild bird serums, 8.28% of 2,004 semidomestic bird serums, and 3.90% of 231 exotic bird serums tested. Although few free-flying wild birds were infected with VVND virus in this epornitic, the isolation of domestic NDV strains from free-flying wild ducks and mourning doves suggests the potential for transportation of NDV over long distances by migratory birds.     

Long-Term Effects of Aeration and Fire on Invasion of Exotic Grasses in Mixed-Brush Plant Communities

Invasion of exotic grasses into grasslands dominated by native plants changes fire cycles and reduces biodiversity. Brush management practices that create soil disturbance, such as aeration, may potentially result in invasion of exotic grasses and replacement of native vegetation. We tested the hypothesis that a long-term effect of aeration and prescribed burning is an increase in exotic grasses. The study was conducted at the Chaparral Wildlife Management Area in the western south Texas plains where four treatments were evaluated: aeration, warm-season burn, aeration followed by a warm-season burn, and no treatment (control). The experimental design was a randomized complete block with four replicates. We estimated percentage canopy cover of exotic grasses, native grasses, forbs, litter, bare ground, and woody and succulent plants in 2007. There was a multivariate main effect among treatments for the dependent variables absolute canopy cover of exotic grasses, native grasses, forbs, litter, and bare ground (Wilks's Lambda F_15,179.84 = 2.78, P = 0.001). Variables that contributed to the significant overall effect included litter (F_3,69 = 4.32, P = 0.008) and native grasses (F_3,69 = 6.11, P = 0.001). The multivariate main effect of treatment was significant (Wilks's Lambda F_9,180.25 = 2.04, P = 0.038) for the relative canopy cover of herbaceous species. Relative cover of exotic grasses was 31% higher (P = 0.024) in control than in the prescribed burn treatment. Native grasses relative cover was 30% higher (P = 0.003) in prescribed burn than in the control treatment. We did not detect differences among treatments in the percentage of total woody and succulent plants canopy cover (P = 0.083). Under the environmental conditions at the time of the study, aeration and/or prescribed burning do not increase exotic grasses.