Genetic Characteristics of Restored Elk Populations in Kentucky

Translocations are a common management practice to restore or augment populations. Understanding the genetic consequences of translocation efforts is important for the long-term health of restored populations. The restoration of elk (Cervus canadensis) to Kentucky, USA, included source stocks from 6 western states, which were released at 8 sites in southeastern Kentucky during 1997–2002. We assessed genetic diversity in restored herds and compared genetic similarity to source stocks based on 15 microsatellite DNA loci. Genetic variation in the restored populations was comparable to source stocks ( allelic richness = 3.52 and 3.50; expected heterozygosity = 0.665 and 0.661 for restored and source, respectively). Genetic differentiation among all source and restored populations ranged from 0.000 to 0.065 for pairwise F_ST and 0.034 to 0.161 for pairwise Nei's D_A. Pairwise genetic differentiation and Bayesian clustering revealed that stocks from Utah and North Dakota, USA, contributed most to restored populations. Other western stocks appeared less successful and were not detected with our data, though our sampling was not exhaustive. We also inferred natural movements of elk among release sites by the presence of multiple genetic stocks. The success of the elk restoration effort in Kentucky may be due, in part, to the large number of elk (n = 1,548), repeated releases, and use of diverse source stocks. Future restoration efforts for elk in the eastern United States should consider the use of multiple stock sources and a large number of individuals. In addition, preservation of genetic samples of founder stock will enable detailed monitoring in the future. © 2020 The Authors. The Journal of Wildlife Management published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.     

白鹤冷冻精液人工授精实验

为了探索鹤类精液冷冻保存和使用技术,2003～2005年,进行了白鹤(Grus leucogeranus)的冷冻精液保存及人工授精实验。使用Beltsville家禽精液稀释液作为白鹤精液稀释液,12%的二甲基亚砜(DMSO)为冷冻液。精液样本冷冻经过三个阶段的降温,最后保存在液氮中。成功保存了编号93001雄性白鹤精液36 支（0.2 ml/支）。冷冻精液在0~4℃冰水中解冻3~5 min,解冻后白鹤精液精子活率为29.3%±15.5%（n=16）,2004和2005年分别为92101号雌鹤产的两窝卵进行人工授精实验,2年共产卵5枚,其中1枚卵受精并成功孵化。实验发现在雌鹤产卵前一周和产卵期间每天输精,并增加每次输精量,同时在产完1枚卵后4 h内完成一次输精,效果最佳。     

Food consumption and retention time in captive whooping cranes (Grus americana)

Food consumption, digesta retention time, and food preference were measured for captive whooping cranes fed pelleted diets. The basal commercial diet was compared to four mixtures containing 70% basal and 30% of one of four important winter foods for the whooping crane: blue crab (Callinectes sapidus), wolfberry fruit (Lycium carolinianum), live oak acorn (Quercus virginiana), or common Rangia clam (Rangia cuneata). Because captive birds would not eat whole foods, we were prevented from direct food preference tests. Food passed through the gut rapidly, with almost complete elimination within 7 hr. There was some indication that retention time was shorter for the low fiber and high ash and calcium clam diet. Cranes ate less wolfberry feed (g/day) than the other feeds, and all birds ate less wolfberry feed on the day it was first fed, compared to basal diet the previous day. Birds ate more low energy feed than high energy feed. Due to combined effects of low energy content, lower metabolizable energy coefficients, and reduced feed consumption, less energy was assimilated for study diets than basal diet. Apparent shorter retention times for some diets containing whooping crane foods may partly explain lower digestibilities and metabolizable energy of winter whooping crane foods compared to commercial crane diet. Zoo Biol 16:519–531, 1997. © 1997 Wiley-Liss, Inc.     

Histological structure of the cancellous bone layer in Bothriolepis canadensis (Antiarchi, Placodermi)

The Placodermi are extinct basal gnathostomes which had extensive dermal and perichondral bone, but which lacked the endochondral bone which characterizes the more derived bony fishes. Thin sections of bone from a specimen of the antiarch placoderm Bothriolepis canadensis, from the Escuminac Formation (Frasnian, Upper Devonian), Québec, Canada, reveal that part of the cancellous layer in its dermal and endoskeletal bone formed from perichondral bone trabeculae growing around cartilage spheres. The resultant structure mimics that of osteichthyan endochondral bone. The layout and dimensions of this polygonal mosaic patterning of the bone trabeculae and flattened cartilage spheres resemble those of the prismatic layers of calcified cartilage in chondrichthyans. If the lack of endoskeletal bone in chondrichthyans is a derived character, then the structure identified in B. canadensis could represent a 'template' for the formation of prismatic calcified cartilage in the absence of bone.     

不同光强对加拿大一枝黄花生长和叶绿素荧光的影响

以外来入侵种加拿大一枝黄花(Solidago canadensis)为研究对象,在4种光照强度处理下,对其光合色素含量、叶绿素荧光特性、比叶重、植株的生长特征和生物量分配等指标进行了测定分析.结果表明:(1)随着光照强度的减弱,加拿大一枝黄花叶片的Chla、Chlb和Chl(a b)均上升,Chla/Chlb下降,4种光强处理下叶片的初始荧光(Fo)、光系统Ⅱ实际光化学效率(ФPSⅡ)、光系统Ⅱ最大光能转化效率(Fv/Fm)日变化曲线相似,高光强下的Fo、ФPSⅡ和Fv/Fm均小于中、低和弱光强下的,这说明加拿大一枝黄花能适应较大的光强幅度,同时对低、弱光强有一定的抗逆性.(2)生长在高(RI为100%)、中(RI为60%)光强下的加拿大一枝黄花植株正常生长,生长于低(RI为20%)弱(RI为5%)光强下的植株生长不良,表现为植株矮小,茎秆细弱.中度的遮荫对它的生长没有明显影响,但在严重遮阴下生长受抑.(3)生长在高、中光强下的总生物量、地下部分生物量明显增多,低、弱光强处理下的叶生物量比显著增加.结果表明,加拿大一枝黄花在高、中光强下对生长最有利,能够适应较大幅度的光照变化,但在严重遮阴下生长明显受抑,说明该入侵植物不易入侵到密林等光照强度比较弱的生境.     

Do introduced North American beavers Castor canadensis engineer differently in southern South America? An overview with implications for restoration

• 1 Twenty‐five pairs of North American beavers Castor canadensis Kuhl were introduced to Tierra del Fuego Island in 1946. The population has expanded across the archipelago, arriving at the Chilean mainland by the mid‐1990s. Densities range principally between 0.5–2.05 colonies/km. They have an impact on between 30–50% of stream length and occupy 2–15% of landscape area with impoundments and meadows. Beaver impacts constitute the largest landscape‐level alteration in subantarctic forests since the last ice age.
• 2 The colonization pattern, colony densities and impacted area indicate that habitat in the austral archipelago is optimal for beaver invasion, due to low predator pressure and suitable food resources. Nothofagus pumilio forests are particularly appropriate habitat, but a more recent invasion is occurring in adjacent steppe ecosystems. Nonetheless, Nothofagus reproductive strategies are not well adapted to sustain high beaver population levels.
• 3 Our assessment shows that at the patch‐scale in stream and riparian ecosystems, the direction and magnitude of exotic beaver impacts are predictable from expectations derived from North American studies, relating ecosystem engineering with underlying ecological mechanisms such as the relationships of habitat heterogeneity and productivity on species richness and ecosystem function.
• 4 Based on data from the species' native and exotic range, our ability to predict the effects of beavers is based on: (i) understanding the ecological relationships of its engineering effects on habitat, trophic dynamics and disturbance regimes, and (ii) having an adequate comprehension of the landscape context and natural history of the ecosystem being engineered.
• 5 We conclude that beaver eradication strategies and subsequent ecosystem restoration efforts, currently being considered in southern Chile and Argentina, should focus on the ecology of native ecosystems rather than the biology of this invasive species per se. Furthermore, given the nature of the subantarctic landscape, streams will probably respond to restoration efforts more quickly than riparian ecosystems.

     

Fungi associated with a natural epizootic in Fiorinia externa Ferris (Hemiptera: Diaspididae) populations

Stands of eastern hemlock [(Tsuga canadensis (L.) Carrière] in the northeastern United States are in decline, in part from the attack of elongate hemlock scale, Fiorinia externa Ferris (Hemiptera: Diaspididae). From 2001 to the present, a natural epizootic has been observed in populations of F. externa. Initially discovered at the Mianus River Gorge Preserve in Bedford, New York, the epizootic has also been detected in Pennsylvania, New Jersey and Connecticut. Understanding and assessing the identity of the pathogenic micro‐organisms responsible for this natural mortality is crucial for developing biological controls for this pest. We have isolated and taxonomically and genetically identified entomopathogens, phytopathogens and endophytic fungi associated with F. externa. Isolates of the following were obtained: Colletotrichum sp., Lecanicillium lecanii, Beauveria bassiana, Metarhiziopsis microspora, Myriangium sp., Mycosphaerella sp. anamorph, Nectria sp., Botrytis sp., Phialophora sp. and Fusarium sp.     

小飞蓬提取物除草活性的生物测定

以高粱(Sorghum vulgarePers.)、黄瓜(Cucum is sativusL.)、小麦(Triticum aestivumL.)和油菜(BrassicacampestrisL.)为供试对象,用种子萌发法测定了小飞蓬(Erigeron canadensisL.)全株的石油醚、乙酸乙酯和乙醇等3种溶剂提取物的除草活性。小飞蓬的乙酸乙酯与乙醇提取物对4种供试作物均显示出很强的抑制生长作用,浓度达100 mg.mL-1时对小麦和油菜幼苗生长的抑制率均为100%。小飞蓬乙酸乙酯提取物对高粱和油菜的幼根及黄瓜和油菜幼茎的生长有明显的抑制作用。低浓度乙醇提取物对小麦和高粱幼根及幼茎的生长有较强抑制作用,但高浓度时则对黄瓜和油菜的抑制作用较强;6.25 mg.mL-1乙醇提取物对黄瓜、油菜、小麦和高粱幼茎生长的抑制率分别为6.50%、8.58%、21.51%和26.98%;25 mg.mL-1乙醇提取物的抑制率则分别达到61.31%、77.45%、39.78%和46.34%。表明小飞蓬乙酸乙酯和乙醇提取物具有潜在的除草活性。     

Arsenic Uptake and Translocation by Plants in Pot and Field Experiments

A work undertaken by pot and field experiments to assess the suitability of poplars and ferns for the in-situ, phytoextraction, of a dumping site with residues from the roasting process of arseno-pyrite is reported. The main characteristic of this site is the high content of both the As metalloid and heavy metals (e.g., Al, Fe, Cu, Co, Cr, Pb). Two poplar clones (Populus deltoides ‘Dvina’ and Populus x canadensis ‘Orion’) and Pteris vittata (Chinese brake fern) were planted in the contaminated soil both ex situ in pots and in situ. Plant survival, As accumulation in plant tissues, leaf content of pigments, soluble proteins, activity of catalase and SH-groups in both roots and leaves were evaluated during a 24-month study period. Both poplar and fern plants exhibited an increase in the activity of catalase and SH group contents when grown in the presence of pyrite ashes. The results showed that the co-planting system (arsenic-hyperaccumulator fern Pteris vittata and Populus clones) was suitable for phytoextraction of multi-contaminated dumping sites. Agronomic measures such as irrigation, soil tillage and amendments also seem to be necessary for the successful establishment of poplar trees and ferns in contaminated soils in order to enhance plant growth through the improvement of soil conditions.