Response and mortality of beech, fir, spruce and sycamore to rapid light exposure after large-scale disturbance

2021 ◽  
Vol 498 ◽  
pp. 119554
Author(s):  
Matjaž Čater
Keyword(s):  
Large Scale ◽  
Light Exposure ◽  
Large Scale Disturbance

Ecological processes maintaining differential tree species distributions in an Australian subtropical rain forest: implications for models of species coexistence

2000 ◽  
Vol 16 (3) ◽  
pp. 387-415 ◽  
Author(s):  
Igor Debski ◽  
David F. R. P. Burslem ◽  
David Lamb
Keyword(s):  
Species Composition ◽  
Tree Species ◽  
Rain Forest ◽  
Large Scale ◽  
Species Coexistence ◽  
Common Species ◽  
Size Class ◽  
Differential Mortality ◽  
Mixed Composition ◽  
Large Scale Disturbance

All stems ≥ 1 cm dbh were measured, tagged, mapped and identified on a 1-ha plot of rain forest at Gambubal State Forest, south-east Queensland, Australia. The spatial patterns and size class distributions of 11 common tree species on the plot were assessed to search for mechanisms determining their distribution and abundance. The forest was species-poor in comparison to many lowland tropical forests and the common species are therefore present at relatively high densities. Despite this, only limited evidence was found for the operation of density-dependent processes at Gambubal. Daphnandra micrantha saplings were clumped towards randomly spaced adults, indicating a shift of distribution over time caused by differential mortality of saplings in these adult associated clumps. Ordination of the species composition in 25-m × 25-m subplots revealed vegetation gradients at that scale, which corresponded to slope across the plot. Adult basal area was dominated by a few large individuals of Sloanea woollsii but the comparative size class distributions and replacement probabilities of the 11 common species suggest that the forest will undergo a transition to a more mixed composition if current conditions persist. The current cohort of large S. woollsii individuals probably established after a large-scale disturbance event and the forest has not attained an equilibrium species composition.

scholarly journals Ecological Impacts of Megaprojects: Species Succession and Functional Composition

Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2411
Author(s):  
Hamada E. Ali ◽  
Solveig Franziska Bucher
Keyword(s):  
Plant Species ◽  
Large Scale ◽  
Invasive Plant ◽  
Species Traits ◽  
Natural Vegetation ◽  
Ecological Impacts ◽  
Imperata Cylindrica ◽  
Dry Matter Content ◽  
Large Scale Disturbance ◽  
The Impact

Land-use changes have huge impacts on natural vegetation, especially megaprojects, as the vegetation layer is destroyed in the course of construction works affecting the plant community composition and functionality. This large-scale disturbance might be a gateway for the establishment of invasive plant species, which can outcompete the natural flora. In contrast, species occurring in the area before the construction are not able to re-establish. In this study, we analyzed the impact of a pipeline construction on a wetland nature reserve located in northern Egypt. Therefore, we analyzed the plant species occurrence and abundance and measured each plant species’ traits before the construction in 2017 as well as on multiple occasions up to 2 years after the construction had finished on altogether five sampling events. We found that the construction activity led to the establishment of an invasive species which previously did not occur in the area, namely, Imperata cylindrica, whereas five species (Ipomoea carnea, Pluchea dioscoridis, Polygonum equisetiforme, Tamarix nilotica, and Typha domingensis) could not re-establish after the disturbance. The functionality of ecosystems assessed via the analysis of plant functional traits (plant height, specific leaf area, and leaf dry matter content) changed within species over all sampling events and within the community showing a tendency to approximate pre-construction values. Functional dispersion and Rao’s quadratic diversity were higher after the megaproject than before. These findings are important to capture possible re-establishment and recovery of natural vegetation after construction and raise awareness to the impact of megaprojects, especially in areas which are high priority for conservation.

scholarly journals Large-scale disturbance legacies and the climate sensitivity of primary Picea abies forests

2018 ◽  
Vol 24 (5) ◽  
pp. 2169-2181 ◽  
Author(s):  
Jonathan S. Schurman ◽  
Volodymyr Trotsiuk ◽  
Radek Bače ◽  
Vojtěch Čada ◽  
Shawn Fraver ◽  
...  
Keyword(s):  
Picea Abies ◽  
Climate Sensitivity ◽  
Large Scale ◽  
Large Scale Disturbance

scholarly journals Seven Decades of Spontaneous Forest Regeneration after Large-Scale Clear-Cutting in Białowieża Forest do not Ensure the Complete Recovery of Collembolan Assemblages

Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 948
Author(s):  
Marek Sławski ◽  
Małgorzata Sławska
Keyword(s):  
Large Scale ◽  
Life Form ◽  
Group Structure ◽  
Complete Recovery ◽  
Long Term Effects ◽  
Old Growth ◽  
Soil Microarthropods ◽  
Clear Cutting ◽  
Białowieża Forest ◽  
Large Scale Disturbance

The long-term effects of large-scale disturbance on forest ecosystem processes and structure are poorly understood. To assess the effects of large-scale clear-cutting on the taxonomic and functional structure of collembolan assemblages, 18 plots were established in the Polish part of Białowieża Forest. All plots, situated in a mixed Tilio-Carpinetum broad-leaved forest, had eutrophic Cambisol developed on rich glacial deposits. The Collembola assemblages in the stands that had naturally regenerated on large-scale clear-cuts performed at the beginning of the 20th century were compared to those in old-growth forests (i.e., the endpoint of stand development following stand-replacing disturbance). Collembolans, one of the most numerous soil microarthropods, are successfully used to assess the consequences of forest management and ecosystem restoration. Our study tested whether seven decades of spontaneous forest development after large-scale anthropogenic disturbance ensures the complete recovery of the soil Collembola. Using complementary taxonomic and life-form approaches, we provide evidence that the collembolan assemblages associated with the tree stands that had spontaneously developed in large harvesting plots distinctly differed from those in old-growth deciduous forests in this region despite seven decades of regenerative forest succession. The species diversity of the assemblages in the naturally regenerated tree stands was significantly lower, and their life-form structure was noticeably different from those in the reference forests. Moreover, the shift in the functional group structure of the collembolan assemblages in the stands that had regenerated after clear-cutting indicates that their activity seven decades after disturbance is concentrated mainly on the decomposition of the litter in the upper layers, whereas the processes controlled by these organisms in the deeper soil layers are not fully restored.

Large-Scale Disturbances and Their Mitigation Downstream of Shallow Cavities Covered by a Perforated Lid

2004 ◽  
Vol 126 (5) ◽  
pp. 851-860 ◽  
Author(s):  
Stephen A. Jordan
Keyword(s):  
Fundamental Frequency ◽  
Large Scale ◽  
Periodic Oscillation ◽  
Feedback Mechanism ◽  
Complete Disappearance ◽  
Freestream Velocity ◽  
Design Engineers ◽  
Large Scale Disturbance ◽  
Key Factor ◽  
Shallow Cavities

Flow past cavities covered by perforated lids pose a challenging problem for design engineers. Kelvin–Helmholtz waves appear early in the separated shear layers above the perforations that quickly mature into large-scale coherent structures far downstream. This evolution is sustained by a hydrodynamic feedback mechanism within the cavity even when its aft wall is far removed from the lid. Herein, the results from large-eddy simulations show analogous fundamental characteristics between open and perforated-cover cavities. Both adequately scale the fundamental frequency of the large-scale disturbance using the freestream velocity and the cavity width (or lid length). Moreover, the dimensionless frequencies jump to higher modes at equivalent length scales. Unlike the open cavity, one can invoke certain conditions that instigate the instability above the perforations but not a simultaneous long-term feedback mechanism necessary to fully sustain the periodic oscillation. The lid itself offers options for mitigating (or even eliminating) the instability. Results (for laminar separation) show the perforation spacing as the key factor. While maintaining the same fundamental frequency, one can easily dampen its spectral peak to complete disappearance by extending the perforation spacing.

The persistent presence of the dead: recent excavations at the hunter-gatherer cemetery at Zvejnieki (Latvia)

Antiquity ◽  
2013 ◽  
Vol 87 (338) ◽  
pp. 1016-1029 ◽  
Author(s):  
Liv Nilsson Stutz ◽  
Lars Larsson ◽  
Ilga Zagorska
Keyword(s):  
Detailed Analysis ◽  
Large Scale ◽  
Northern Europe ◽  
Social Differentiation ◽  
Burial Practices ◽  
Neolithic Transition ◽  
The Past ◽  
Large Scale Disturbance ◽  
The Dead ◽  
Specific Identity

The well-known Mesolithic cemeteries of Northern Europe have long been viewed as evidence of developing social complexity in those regions in the centuries immediately before the Neolithic transition. These sites also had important symbolic connotations. This study uses new and more detailed analysis of the burial practices in one of these cemeteries to argue that much more is involved than social differentiation. Repeated burial in the densely packed site of Zvejnieki entailed large-scale disturbance of earlier graves, and would have involved recurrent encounters with the remains of the ancestral dead. The intentional use of older settlement material in the grave fills may also have signified a symbolic link with the past. The specific identity of the dead is highlighted by the evidence for clay face masks and tight body wrappings in some cases.

scholarly journals Interplanetary Disturbances Affecting Space Weather

2013 ◽  
Vol 8 (S300) ◽  
pp. 297-306 ◽  
Author(s):  
Robert F. Wimmer-Schweingruber
Keyword(s):  
Space Weather ◽  
Large Scale ◽  
Interplanetary Medium ◽  
Coronal Holes ◽  
Historical Review ◽  
The Sun ◽  
High Speeds ◽  
Large Scale Disturbance ◽  
Mass Ejection ◽  
Very High

AbstractThe Sun somehow accelerates the solar wind, an incessant stream of plasma originating in coronal holes and some, as yet unidentified, regions. Occasionally, coronal, and possibly sub-photospheric structures, conspire to energize a spectacular eruption from the Sun which we call a coronal mass ejection (CME). These can leave the Sun at very high speeds and travel through the interplanetary medium, resulting in a large-scale disturbance of the ambient background plasma. These interplanetary CMEs (ICMEs) can drive shocks which in turn accelerate particles, but also have a distinct intrinsic magnetic structure which is capable of disturbing the Earth's magnetic field and causing significant geomagnetic effects. They also affect other planets, so they can and do contribute to space weather throughout the heliosphere. This paper presents a historical review of early space weather studies, a modern-day example, and discusses space weather throughout the heliosphere.

Public Reaction to Invasive Plant Species in a Disturbed Colorado Landscape

2010 ◽  
Vol 3 (4) ◽  
pp. 390-401 ◽  
Author(s):  
Michael T. Daab ◽  
Courtney G. Flint
Keyword(s):  
Plant Species ◽  
Invasive Plants ◽  
Large Scale ◽  
Tree Mortality ◽  
Invasive Plant ◽  
Public Awareness ◽  
Invasive Plant Species ◽  
North Central ◽  
The Public ◽  
Large Scale Disturbance

AbstractInvasive plant species degrade ecosystems in many ways. Controlling invasive plants is costly for government agencies, businesses, and individuals. North central Colorado is currently experiencing large-scale disturbance, and millions of acres are vulnerable to invasion because of natural and socioeconomic processes. Mountain pine beetles typically endemic to this region have reached epidemic proportions, with up to 80% tree mortality, which opens growing space for invasive plants. In socioeconomic terms, the popularity of this amenity-rich region for tourists and in-migrants has resulted in increased development, often bordering the public land that is common in the American West. Increased recreational access and the construction of new roads and infrastructure disturb ecosystems in an increasingly fragmented landscape. A survey was mailed to more than 4,000 households in a five-county region of north central Colorado to gauge public awareness and attitudes regarding invasive plant species, helping to illuminate whether the public shows a capacity to help land managers detect and respond to invasive plants before they profoundly alter the local ecosystem. Although 88% of respondents had heard or read about invasive plant species, far fewer were familiar with specific, locally targeted species, and fewer still had taken any action to control these species. The overall awareness and concern about invasive plants in the area indicated a capacity for more public participation in management.

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