Attitudes of Rural Communities Toward Dispersing African Wild Dogs in South Africa

Subsistence pastoralists often view large carnivores negatively given that any loss of livestock is likely to represent a significant economic cost. Consequently, large carnivore conservation initiatives in rural landscapes should incorporate appropriate human–carnivore conflict mitigation strategies. In this study, structured interviews with local residents (n = 247) were used for determining attitudes toward African wild dogs (Lycaon pictus) among rural communities neighboring two protected areas in KwaZulu-Natal, South Africa. Contrary to expectations, the majority of respondents (58%) were generally positive toward wild dogs. This was probably due to a lack of livestock depredation by wild dogs and relatively high levels of formal education among respondents. Respondents with greater knowledge of wild dogs and conflict mitigation had more positive attitudes, and most were aware of effective husbandry techniques. The positive attitudes observed in these rural communities may benefit wild dog dispersal from natal home ranges and the future conservation of this endangered carnivore.     

Dominance in domestic dogs revisited: Useful habit and useful construct?

In the last decade, the validity and relevance of the dominance model was regularly put into question regarding relationships between canids like dogs and wolves, and consequently, human–dog relationships as well. The concept underlying this model, scientifically defined as an intervening variable reflecting status difference between individuals, is applicable when formal status signals symbolize the long-term relationship between individuals, resulting in a formalized dominance hierarchy. This article reviews the basics underlying the concept of dominance and reflects on the value and importance of some new quantitative studies on the applicability of the concept of dominance in domestic dogs. The conclusions are, first, that formal dominance is present in the domestic dog, expressed by context-independent unidirectional formal status signals. Consequently, formal dominance (e.g., submission) plays an important role in assessing status in dog–dog relationships. Second, that nonverbal status–related communication in humans resembles that in dogs to a considerable degree, and hence dogs may be well able to interpret this human status–related nonverbal communication from their perspective. Dominance is therefore also likely to play a role in human–dog relationships. Hence, the dominance concept might be useful to explain the development of certain problems in dog–dog and dog–human relationships. However, enforcing a dominant status by a human may entail considerable risks and should therefore be avoided.     

Analysis of regional variation of height growth and slenderness in populations of six urban tree species using a quantile regression approach

Inventory data of six urban tree species from seven cities across Germany were used to model regional variation of height growth, allometric scaling, and slenderness over a wide range of size and age using a quantile regression approach. Variation within and between species and cities was large. Height did not reach an asymptote but declined at higher ages, presumably because of reduction cuts. Allometric scaling and slenderness varied with wind climate, modulus of elasticity, and coefficient of drag. Our data do not support the use of a threshold value of slenderness in tree risk assessment.     

Effect of variable retention cutting on the relationship between growth of coarse roots and stem of Picea mariana

Silviculture heading for structural heterogeneity creates many single trees standing at stand margins, inner edges or in remnant tree groups. As they played just a minor role in the age class forest, the growth behaviour of strongly released trees is rather unexplored. Here we show how retention cutting, presently spreading in the boreal of Québec province, affects stem and coarse root growth of remained single black spruce [Picea mariana (Mill.) Britton]. Increment cores from roots and stems of 125 trees show that retention cutting triggers coarse root growth of the remaining trees. Compared with reference trees retention trees accelerate root in relation to stem growth. Mean and variability of the root–stem allometry significantly rise after retention cutting. The found acceleration of root in relation to stem growth means mechanical stabilisation of the retention trees and corroborates the retention cutting method. Evaluation of silvicultural treatments can be incomplete and misleading as long as they are just based on aboveground reactions and neglect root growth.     

Actor-Network-Theory perspective on a forestry decision support system design

Use of decision support systems (DSS) has thus far been framed as a social process of adoption or technical process of usability. We analyze the development of a DSS as a process of institutionalization of new as well as drift of existing practices. We write an Actor-Network-Theory (ANT) account, i.e. an interpretive study, that follows the traces left by both human and non-human actors (e.g. technology, methodologies, etc.) to understand how a DSS development project institutionalizes DSS technology in several forest management organizations in the German state of Rheinland Pfalz. The research has an innovative value since it uses ANT in the design of a DSS, hence affecting it, while commonly ANT has been used to understand why networks work or do not. Moreover, we use a new technology (PREZI^TM, www.prezi.com) for the visualization of the whole actor network coherent to the ANT methodology, i.e. “keeping the social flat.” As a result, the development of the ANT account proposed in the present paper, even if still partial, supports the design of new technologies being introduced in current practice and generates an important learning effect thanks to the underpinning interpretative approach.     

New invasive predator reduces the abundance of native prey in a cold-temperate marine fouling community

1. Invasive species threaten the conservation of marine environments, and urgent management strategies are needed to prevent their introduction, establishment and spread. Specifically, marine invasive predators destabilize ecological interactions and alter community structure and function. However, most of the evidence showing the effect of these predators is restricted to a few species and regions, while for others the information remains scarce.
2. This study experimentally evaluated the ecological effects of the sea slug Pleurobranchaea maculata, a recently introduced invasive predator, on the fouling communities of a cold-temperate port in the South-western Atlantic.
3. The results show that increasing predation pressure reduces significantly the abundance of sea anemones, which are among the preferred prey items.
4. This study reveals new evidence to help better understand the effects of P. maculata on the biological communities of a recently invaded region. Furthermore, it provides the first experimental evidence supporting the hypothesis that marine invasive predators can induce a significant decrease in the abundance of native species in benthic communities of cold-temperate marine environments in the South-western Atlantic.

     

Performance Assessment of Chlorophyll Meter to Determine When to Irrigate Wheat under Different Soil Moisture Deficit Conditions: An Initial Study

ABSTRACT

Proper irrigation timing can minimize the negative impacts that reduce crop yields. Therefore, in an initial pot experimental study, we assessed the SPAD (Soil–Plant Analysis Development)-chlorophyll meter as a tool to determine proper irrigation timing of wheat under different soil water deficit conditions in a controlled-environment greenhouse. The treatments were controlled irrigation at 100% (T₁), 70% (T₂), 50% (T₃) and 30% (T₄) of soil water content at field capacity; and the growth stages were development, mid-season and late-season. SPAD readings were measured pre-irrigation events. The results indicated that the T₃ and T₂ achieved maximum grain yield per accumulated crop evapotranspiration, i.e. water productivity (0.82 and 0.76 kg m^?3), and were at par with T₁. Moreover, the SPAD readings had a high Pearson’s correlation coefficient with crop evapotranspiration (r = 0.95; P ≤ 0.001) and wheat grain yield (r = 0.90; P ≤ 0.001), indicating that SPAD reading could be used to reliably estimate when to irrigate wheat. Therefore, T₃ and T₂ SPAD readings were averaged to estimate a target limit at which irrigation should be applied. Accordingly, the target limit was defined as >44.76 for the development stage, >50.72 for the mid-season stage, and >37.64 for the late-season stage; readings below this target limit indicate that it is time to irrigate.     

镉对白菜活性氧代谢及H2O2清除系统的影响

研究不同浓度镉对白菜(Brassica campestris L.ssp.chinensis)叶片活性氧产生及H2O2清除酶活性影响。结果表明,培养液中加镉增加了白菜叶片中超氧自由基(O2-)的产生速率和H2O2含量,过氧化产物丙二醛(MDA)含量随培养液中镉浓度和镉处理时间增加而增加。在加镉条件下,抗坏血酸过氧化物酶(APX)活性、脱氢抗坏血酸还原酶(DR)和谷胱甘肽还原酶(GR)活性升高,抗坏血酸(AsA)和谷胱甘肽(GSH)含量增加。     

中国李和樱桃李及其种间杂种果实香气成分分析

 采用顶空固相微萃取—气质联用技术分析了中国李（Prunus salicina）‘绥李3号’、樱桃李（P. cerasifera）‘红果樱桃李’及其种间杂种‘蜜思李’的果实香气成分。结果表明,3种果实香气物质组成及含量存在显著差异,‘蜜思李’、‘绥李3号’和‘红果樱桃李’分别检测出58、53和29种香气成分,且‘蜜思李’香气物质含量最高;‘绥李3号’主要香气物质是醛类,‘红果樱桃李’为醇类,‘蜜思李’为酯类;γ–十二内酯和γ–癸内酯是‘蜜思李’特有香气物质;根据香气成分的种类及含量,可将‘蜜思李’和‘红果樱桃李’分别划为“酯香型”李和“醇香型”李类型。