Regrowth and revegetation in temperate Australia presents a conservation challenge for reptile fauna in agricultural landscapes

Secondary vegetation, associated with changes in land use, presents a conservation issue in the preservation of biological diversity in agricultural landscapes. We examine the interactive effect of eucalypt regrowth and rock habitat on reptile species richness and assemblage structure in fragmented agricultural landscapes in south-eastern Australia. Zoogeographic and geomorphic factors influenced species richness and community composition. Saxicolous and arboreal species were less abundant in grassy woodland regrowth, whereas Bassian and fossorial species responded positively to forest regrowth (and tree plantings). Regrowth with rock habitat had higher reptile richness, and more old growth-associated taxa, than regrowth without rock habitat. Thus, the presence of saxicolous habitat can reduce the time required for regrowth to attain a climax community structure and elements of old growth fauna. However, in the absence of vegetation management, secondary vegetation can reduce habitat suitability for a broad range of reptiles. In agricultural landscapes historically supporting savannah-like vegetation, habitat manipulation may be necessary to maintain reptile diversity. Furthermore, tree plantings in temperate agricultural landscapes should aim to restore historical vegetation composition and structure, thereby reflecting the habitat requirements of extant species and facilitating evolutionary processes. In grassy woodland ecosystems, this may involve heterogeneous plantings which emulate natural levels of canopy cover and solar penetration. Maintaining biodiversity in agricultural landscapes will therefore involve managing trade-offs to preserve areas of dense regeneration for regrowth-dependant fauna, while at the same time, creating open-canopy environments to enhance habitat for ectothermic organisms.     

蜥蜴亚目的爬行动物

本文介绍了美国 9科、2 5属、1 35种和中国 8科、34属、1 2 0种蜥蜴亚目的爬行动物     

Characterization of Salmonella isolates from captive lizards

Reptile-associated salmonellosis in humans is an increasing public health issue. This study aimed at characterizing Salmonella isolates from captive lizards and to compare them to human isolates. Salmonella was isolated from 25 of 33 cloacal and 47 of 79 faecal samples from captive lizards (75.8 and 59.5%, respectively). The strains belonged to 44 serotypes of subspecies I (27 serotypes), II (9), IIIb (3) and IV (5). Two strains, one of serotype Enteritidis and one of serotype Amsterdam, were resistant to nitrofurantoin. Invasion assays in Caco-2 cells were performed with 40 saurian isolates of subspecies I, 15 isolates of subspecies II, 4 strains of subspecies IIIb, 6 subspecies IV isolates and 17 human isolates of corresponding serotypes of subspecies I. Saurian isolates belonging to subspecies I invaded the Caco-2 cells to a higher extent than those from the other subspecies. The human isolates invaded the Caco-2 cells to a lesser degree compared to their saurian counterparts. In the same strains, the presence of virulence genes agfA, shdA, spvR, pefA and sopE was determined using PCR. Whereas agfA was detected in all strains, pefA was only detected in one saurian and in the human serotype Enteritidis strains. The spvR gene was detected in the same serotype Enteritidis strains and in 33% of the subspecies IV strains. The shdA gene was present in all the human isolates and in 86% of subspecies I saurian isolates. SopE was found in 17% of the human isolates, in 24% of the saurian subspecies I strains and in all of the subspecies IV strains.     

Echocardiographic and radiographic findings in a cohort of healthy adult green iguanas (Iguana iguana)

ObjectivesTo describe characteristics of echocardiography and cranial coelomic radiography in a cohort of iguanas.AnimalsTwenty apparently healthy adult green iguanas (Iguana iguana) from a reptile sanctuary.MethodsPhysical examination, radiography, two-dimensional and color Doppler echocardiography were performed to assess cardiac structures and function, and any related normal or abnormal findings were recorded.ResultsEchocardiographic examination was possible without sedation and allowed visualization of the great vessels, atria, and ventricle. Some structures could not be evaluated in a minority of the iguanas due to individual differences in bony conformation and imaging quality. Suspected abnormal echocardiographic findings in 3 iguanas included pericardial effusion (n = 1) and enlarged caudal vena cava and/or sinus venosus (n = 2). Objective measurements were repeatable as assessed by within-subject coefficient of variation, and reliable as assessed by intra-observer intraclass correlation coefficient. Left atrial and ventricular measurements were significantly correlated with body weight. Valve regurgitation was common, with atrioventricular valve regurgitation present in 53% (9/17) and aortic or pulmonic valve regurgitation in 71% (12/17) of otherwise normal iguanas. A heart murmur was not appreciated during examination of any of the iguanas. Heart size cannot be measured radiographically due to superimposition and silhouetting of other coelomic structures. Echocardiographic or radiographic findings consistent with mineralization of the great vessels were present in 76% of iguanas (13/17).ConclusionsEchocardiography in iguanas is well tolerated without sedation and allowed both subjective evaluation and structural measurements. Valve regurgitation and great vessel mineralization were commonly observed in this cohort of apparently healthy adult iguanas.     

安徽省两栖爬行动物物种分布特征

基于现有的安徽省两栖爬行动物分布资料,系统整理物种分布数据,建立两栖爬行动物地理分布原始数据库。运用GIS技术,以县级行政区为地理单元,分析物种丰富度格局,通过多元统计分析,研究物种多样性的区域分异。结果表明,皖南山地丘陵和大别山山地丘陵地带物种丰富度最高：淮北平原、江淮丘陵的物种丰富度相对较低;但淮北平原和江淮丘陵的部分山地丘陵物种丰富度相对较高。根据各县的分布型物种数量分布,当聚为2组（Jaccard系数大于7.612）时,安徽省物种分布型区域分异基本上呈现山区系组（皖南山区和大别山区）和丘陵平原组特征,当聚为3组（Jaccard系数小于5.075）时,丘陵平原组又可分为江淮丘陵平原组和淮北平原组;当划分为4组（Jaccard系数等于2.537）,山地区系组又可以分为皖南山区组和大别山区组。