Evaluation of alternative approaches to rainforest restoration on abandoned pasturelands in tropical North Queensland,Australia

The lag time for natural recruitment of tropical rainforest species in abandoned pastureland is very long, therefore artificial restoration techniques have been employed to accelerate natural seedling recruitment. The objectives of this study were to investigate: (1) the success/failure of establishment 502 seedlings belonging to 15 species from 11 families planted approximately ten years ago; and (2) the influence of different restoration techniques on enhancing natural recruitment during this period. The study was conducted in the wet tropical rainforest region of northeast Queensland, Australia as a completely randomized block design involving five treatments with two replicates. In each plot, 63 tropical rainforest seedlings from one or a combination of species were planted randomly. Two control plots were laid out where no seedlings were planted. Survival, height and diameter data were taken on the seedlings ten years after planting. Each 11×17 m² plot was further divided into 187, 1×1 m² subplots. Within each subplot all seedlings recruited were located and identified. Canopy cover was estimated using belt transects 1 m apart that ran in an east–west direction across the plots. Within each plot the percentage of grass, and the crown cover were estimated using the Braun‐Blanquet cover abundance scale. Survival rate of planted seedlings varied across the treatment plots. The survival rate ranged from 65 to 75 per cent for primary‐promoter species, 85 to 100 per cent in middle‐phase species and 42 to 57 per cent for mature‐phase species. No Pilidiostigma tropicum seedlings survived in any treatment. Fourteen species recruited naturally across the treatment plots. A total of 410 seedlings were naturally recruited from 11 different families in the ten‐year‐old reforested site. The highest natural recruitment (236 seedlings) occurred in Treatment 3, where Omalanthus novo‐guineensis seedlings were planted with eight primary‐promoter species, followed by 99 in Treatment 5 where a group of primary‐promoters, middle phase species and mature‐phase species were planted together, 36 in Treatment 4 (Alphitonia petriei planted with eight primary‐promoter species), 10 in Treatment 2 where only Omalanthus novo‐guineensis seedlings were planted, and 13 in control plots. Grass cover declined with increasing species diversity and increased canopy cover. The results indicate that the diversity of species used in restoration had a major influence on natural recruitment. Copyright © 2004 John Wiley & Sons, Ltd.     

The introduction of Hymenoscyphus fraxineus to Northern Ireland and the subsequent development of ash dieback

Ash dieback caused by Hymenoscyphus fraxineus was first recorded in Northern Ireland (NI) in November 2012. The disease was observed only on recently (<6 years) planted trees. An in-depth case study in 2015 of an ash plantation with severe symptoms indicated that many of the trees were infected at the time of planting. Apothecia were observed developing from pseudosclerotia beneath the epidermis of dead branches still attached to the tree, suggesting a possible mechanism whereby H. fraxineus could be disseminated without leaf or rachises infection. Apothecia also formed on roots, indicating that infections may also occur in the soil. Often young trees were killed by the formation of large basal lesions which did not arise from stem infections higher up. On first detecting the disease on the island of Ireland the Governments of NI and the Republic of Ireland published an “All-Ireland Chalara Control Strategy.” Part of that strategy was a ban on the importation of ash plants from regions where the disease was known to be present, to prevent the introduction of further inoculum, and the implementation of an ‘eradication and containment’ policy with the aim of preventing the establishment and spread of the disease. While these measures may have slowed disease establishment, they were ultimately unsuccessful and by 2018 ash dieback was widespread and established throughout the whole of NI in plantations and in the wider environment.     

The Unquantified Risk of Post-Fire Metal Concentration in Soil: a Review

Forest fire is a natural disturbance that occurs in many terrestrial ecosystems specifically in the semi-arid environments and is considered to be an important cause of environmental change. Though many causes of fire are identified, including lightning, volcanic eruption, power line sparks, etc., human involvement is the most significant factor. Fire events are able to alter the physical, chemical and biogeochemical properties of the soil and surface materials and are able to release major and trace metals into the environment. This may be more significant in mining-affected and industrial landscapes, where elevated concentrations of metals present in the soil. After the fire event, metals become more mobile due to the increase in soil surface exposure and the mobility associated with ash dispersal. This mobility may increase the bioavailability of the metals, which may generate water quality issues and may contribute to human and environmental health concerns. Even though, the influences of fire on many soil properties are well established, the behaviour of metals with respect to fire is not well investigated. However, a few studies report that major and trace metals include Cd, Cr, Co, Cu, Hg, Mn, Ni, Pb, Zn and As are mobilized after fire with increased concentrations in soil and water resources and this might pose a risk to human health and ecosystems. Climate change may increase the intensity, frequency and areal extend of fire events and hence increase the metal concentrations and their potential health impacts. This paper reviews post-fire (wild fire) mobility of metals in soil common in contaminated forest ecosystems. The human and ecological health risks of these metals are also considered.     

Herbicide efficacy for aquatic Alternanthera philoxeroides management in an early stage of invasion: integrating above‐ground biomass,below‐ground biomass and viable stem fragmentation

Alternanthera philoxeroides is a problematic invasive plant in many regions of the world that is difficult to control once naturalised. It poses a threat to agricultural productivity, biodiversity and social amenity values of aquatic environments. Significant research has been conducted internationally, regarding the efficacy of different herbicides for control of A. philoxeroides. However, no studies have looked at key aspects of control for effective management in an early stage of invasion of aquatic environments, hindering eradication and control programmes. This study evaluates the efficacy of herbicides and surfactants on key A. philoxeroides response metrics, including control of above‐ground biomass, below‐ground biomass and production of viable stem fragments. This study concluded that glyphosate (isopropylamine salt) minimises viable stem fragment production post‐herbicide application, compared with imazapyr and metsulfuron, thus reducing the potential for dispersal throughout catchments and waterways. In contrast, imazapyr and metsulfuron provided more effective control than glyphosate for A. philoxeroides growing on exposed embankments. We propose that an effective management strategy for early invasion of aquatic A. philoxeroides, using herbicides, would be to conduct initial applications of glyphosate to control overwater biomass and limit dispersal of viable stem fragments. Once infestations have been forced back to the embankment, imazapyr or metsulfuron treatments will provide longer term control.     

On the present breeding status of the scarlet ibis Eudocimus ruber along the north-eastern coast of South America

During 1970–72 aerial surveys were made along the coasts of the Guianas, South America, and a reliable assessment of the present breeding status of the scarlet ibis (Eudocimus ruber (L.)) along these coasts was obtained. During this period seven scarlet ibis breeding colonies were active simultaneously, with a total number of about 20,000 breeding pairs, over half in Surinam.From correspondence with other ornithologists, it appears that little is known about the present breeding status in Columbia, in the Venezuelan llanos, and along the coast of eastern Brazil.It is argued that in the future adequate guarding of the breeding areas (and possibly also of the feeding areas) would be necessary to ensure the conservation of the species.     

1996-2006世界主要切花、盆花产销变化

2007年,业内著名媒体——荷兰《Flower Tech》杂志创刊10周年,为此该刊推出了系列报道,回顾了1996至2006年世界上主要切花和盆花生产销售情况,包括10年来影响生产的重大变革,并预测了未来几年世界花卉业发展趋势。我刊特意选取了其中两篇文章分两次刊登,以飨读者。     

Ecology,distribution and control of the invasive weed Nassella trichotoma (Nees) Hack. ex Arechav.: A global review of current and future challenges

Nassella trichotoma (serrated tussock) is a highly invasive perennial C₃ weed from South America. It grows in most soil conditions, can resist fire and frost, and is unpalatable to grazing animals. Each plant can produce up to 140,000 seeds annually, and together, these characteristics make it a damaging landscape weed. It has diminished the agricultural carrying capacity of pastures in south-eastern Australia, New Zealand and South Africa, and emerging populations have now been identified in Europe and the United States, and bioclimatic models suggest its distribution could significantly expand within these regions in the near future. Research into control methods for this weed has been explored, and these include herbicides applied alone and in combination, the establishment of plant competition, the introduction of seed mitigation fencing, grazing management and exclusion zones, specific biological management and alteration of soil composition. Currently, the most effective and widely used control method is the residual herbicide flupropanate (2,2,3,3-tetrafluoropropanoic acid). This review will investigate the ecology, distribution, current control techniques and past research on this species, and make recommendations for future research and management.