scholarly journals Status and Impact of Walnut Twig Beetle in Urban Forest, Orchard, and Native Forest Ecosystems

2019 ◽  
Vol 117 (2) ◽  
pp. 152-163 ◽  
Author(s):  
Steven J Seybold ◽  
William E Klingeman ◽  
Stacy M Hishinuma ◽  
Tom W Coleman ◽  
Andrew D Graves
Fact Sheet ◽  
2005 ◽  
Author(s):  
Bethany L. Woodworth ◽  
Carter T. Atkinson ◽  
Michael D. Samuel ◽  
Dennis A. LaPointe ◽  
Paul C. Banko ◽  
...  

2020 ◽  
Vol 12 (4) ◽  
pp. 712 ◽  
Author(s):  
Xiaofei Wang ◽  
Guang Zheng ◽  
Zengxin Yun ◽  
L. Monika Moskal

Tree spatial distribution patterns such as random, regular, and clustered play a crucial role in numerical simulations of carbon and water cycles and energy exchanges between forest ecosystems and the atmosphere. An efficient approach is needed to characterize tree spatial distribution patterns quantitatively. This study aims to employ increasingly available aerial laser scanning (ALS) data to capture individual tree locations and further characterize their spatial distribution patterns at the landscape or regional levels. First, we use the pair correlation function to identify the categories (i.e., random, regular, and clustered) of tree spatial distribution patterns, and then determine the unknown parameters of statistical models used for approximating each tree spatial distribution pattern using ALS-based metrics. After applying the proposed method in both natural and urban forest sites, our results show that ALS-based tree crown radii can capture 58%–77% (p < 0.001) variations of visual-based measurements depending on forest types and densities. The root mean squared errors (RMSEs) of ALS-based tree locations increase from 1.46 m to 2.51 m as the forest densities increasing. The Poisson, soft-core, and hybrid-Gibbs point processes are determined as the optimal models to approximate random, regular, and clustered tree spatial distribution patterns, respectively. This work provides a solid foundation for improving the simulation accuracy of forest canopy bidirectional reflectance distribution function (BRDF) and further obtain a better understanding of the processes of carbon and water cycles of forest ecosystems.


Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 842 ◽  
Author(s):  
Gentili ◽  
Ferrè ◽  
Cardarelli ◽  
Montagnani ◽  
Bogliani ◽  
...  

The introduction of invasive alien plant species (IAPS) can modify plant-soil feedback, resulting in an alteration of the abiotic and biotic characteristics of ecosystems. Prunus serotina, Quercus rubra and Robinia pseudoacacia are IAPS of European temperate forests, where they can become dominant and suppress the native biodiversity. Assuming that the establishment of these invasive species may alter native forest ecosystems, this study comparatively assessed their impact on ecosystems. This study further investigated plant communities in 12 forest stands, dominated by the three IAPS and native trees, Quercus robur and Carpinus betulus (three plots per forest type), in Northern Italy, and collected soil samples. The relationships between the invasion of the three IAPS and modifications of humus forms, soil chemical properties, soil biological quality, bacterial activity and plant community structure and diversity (α-, β-, and γ-diversity) were assessed using one-way ANOVA and redundancy analyses (RDA). Our comparative study demonstrated that invaded forests often had unique plant and/or soil properties, relative to native forests, and the degree of dissimilarity depended on the invasive species. Particularly, Q. rubra is related to major negative impacts on soil organic horizons and low/modified levels of microarthropod and plant biodiversity. R. pseudoacacia is associated with an altered base content of soil and, in turn, with positive feedback to the soil biological quality (QBS-ar) and plant diversity, but with a high cover compared with other alien plant species. P. serotina is associated with intermediate impacts and exhibits a plant species assemblage that is more similar to those of native forest stands. Our work suggests impact-based management decisions for the three investigated IAPS, since their effects on the diversity and composition of resident ecosystems are very different.


1996 ◽  
Vol 23 (4) ◽  
pp. 387 ◽  
Author(s):  
S. A. May ◽  
T. W. Norton

The current knowledge is reviewed of the diet and predator–prey relationships of the feral cat (Felis catus), fox (Vulpes vulpes) and dingo (Canis familiaris dingo) (including wild dogs). The effect of forest fragmentation by roads on the use of native forest ecosystems by these species and the significance of this for native fauna is considered. The cat, fox and dingo are significant predators in Australia that interact with native fauna in various ways, including predation, competition for resources, and transmission of disease. On the basis of current knowledge, it is clear that the nature and impact of predation by the cat, fox and dingo on native fauna are primarily determined by prey availability, although there are exceptions to this rule. Generally, dingoes prey upon large to medium-sized prey species (e.g. wallabies, common wombats, and possums), foxes prey upon medium-sized to small prey (e.g. possums and rats) and consume a significant component of scavenged material and vegetation, while cats also prey upon medium-sized to small prey, but may have a greater proportion of reptiles and birds in their diet. The cat is generally considered to be an opportunistic predator and to have contributed to the demise of a number of mammals. The fox is considered more of a threat to small native mammals and it has been asserted that all species of mammals that fall within the critical weight range (CWR) of 120–5000 g are at risk of local extinction when the fox is present. The severity of the impact of the dingo upon the native fauna is considered to be minimal, at least in comparison with the impact that the cat and fox can have on populations. The dingo is not considered a threat to CWR mammals in undisturbed environments. The fox, feral cat and dingo are all considered to have the ability to selectivity prey upon species and, to some extent, individual sexes and age-classes of a number of larger prey species. Although many of Australia's forested areas are relatively heavily fragmented by roads, there are no published studies specifically investigating the use of roads by feral predators. Information on the distribution and abundance of foxes, cats and dingoes in these ecosystems, their ecology and their impact on native fauna is particularly limited. Further, the extent to which roads influence the distribution and abundance of these species and the consequences of these for native fauna are poorly known. One of the most important research needs is to establish the relative impact that exotic predators may have on native fauna under varying degrees of road construction within native forests. For example, are areas with and without roads in forests used differently by exotic predators and what is the significance of this in terms of the potential impact on fauna? The extent to which feral predators forage away from roads needs further investigation, as does the rates of predation within edges, because this may have several consequences for the design, location and size of retained strips and wildlife corridors as well as restoration programmes. Further observations on regional differences influencing predator–prey interactions are required, as is research on the potential impacts on native fauna resulting from prey selection in forests subjected to various degrees of fragmentation and modification.


2012 ◽  
Vol 8 ◽  
pp. 1-9 ◽  
Author(s):  
Anton Fischer

In the temperate zone windstorms and bark beetle attacks represent the main natural forest disturbances; in steep mountain areas snow avalanches also may “destroy” forest stands completely. In the densely populated and intensively used temperate zone of Europe affected forest stands will be cleared and reforested immediately after such “catastrophes”. Therefore we have only little knowledge about the influence of such natural disturbances on both the stand development and the biodiversity of native forest ecosystems. And we do not have quantitative data on to which degree forest management changes the biodiversity compared to the natural disturbances. Since about two decades several permanent plot studies have been running in European forests affected by such natural disturbances, mainly with focus on plant species. Here we first outline the importance of disturbances for biodiversity in forest ecosystems and then discuss whether it is possible to combine both biodiversity protection and forest management. For that we use four recent case studies carried out in the two oldest national parks in Germany, three of them being long-term observations on permanent plots for up to two decades. Disturbances like wind throw, bark beetle outbreak and snow avalanche strongly influences the tree layer structure, creating micro-habitats for many plant, animal and fungi species, which naturally belong to the forest ecosystem. Such disturbances in future should be included into management schemes in forestry to improve biodiversity. We found evidence that it is really possible to combine timber utilization with biodiversity protection. As long as the management impact is reduced (e.g. single tree harvesting, using natural regeneration), species diversity of several taxonomic groups (in our study: vascular plants, soil living Carabidae, and soil living fungi) may not be different significantly from a pristine forest. Interconnecting resource use with biodiversity protection will be a main task for both foresters and conservationist in the decades to come – and it seems to be a possible option for a sustainable land use in many parts of the world.doi: http://dx.doi.org/10.3126/botor.v8i0.5552 Botanica Orientalis – Journal of Plant Science (2011) 8: 1-9


Sign in / Sign up

Export Citation Format

Share Document