scholarly journals Tree Age Distributions Reveal Large-Scale Disturbance-Recovery Cycles in Three Tropical Forests

2017 ◽  
Vol 7 ◽  
Author(s):  
Mart Vlam ◽  
Peter van der Sleen ◽  
Peter Groenendijk ◽  
Pieter A. Zuidema
Keyword(s):  
Tropical Forests ◽  
Large Scale ◽  
Tree Age ◽  
Large Scale Disturbance ◽  
Recovery Cycles ◽  
Disturbance Recovery

Gap dynamics of forest trees: A review with particular attention to boreal forests

2001 ◽  
Vol 9 (1) ◽  
pp. 1-59 ◽  
Author(s):  
J McCarthy
Keyword(s):  
Tropical Forests ◽  
Boreal Forests ◽  
Large Scale ◽  
The United States ◽  
Small Scale ◽  
Gap Dynamics ◽  
Large Scale Disturbance ◽  
Temperate Deciduous ◽  
Gap Disturbance ◽  
Multiple Trees

Small-scale gap disturbance in forests is reviewed. Caused by the death of individual or multiple trees with subsequent fall from the canopy, gaps have been extensively studied in temperate deciduous and tropical forests for the past 20 years. This review considers much of this research with a view to assessing the importance of gap disturbance in boreal forests. Because of the ubiquity of large-scale, stand-initiating disturbances such as landscape-level fires, epidemic insect outbreaks, and periodic extensive windthrow events, gap processes in boreal forests have received little attention. Research in the Scandinavian and Russian boreal forest, as well as in high-altitude boreal "outliers" found in Japan and the United States, is showing that gap disturbance determines forest structure and processes to a greater extent than previously assumed. Boreal forests dominated by the shade-tolerant fir (Abies) – spruce (Picea) complex are particularly well-adapted to the development of long-term, old-growth continuity in the absence of large-scale disturbance. Key words: gap dynamics, disturbance, boreal forests, temperate forests, tropical forests, silviculture.

Climate change refugia: landscape, stand and tree-scale microclimates in epiphyte community composition

2021 ◽  
Vol 53 (1) ◽  
pp. 135-148
Author(s):  
Christopher J. Ellis ◽  
Sally Eaton
Keyword(s):  
Climate Change ◽  
Community Composition ◽  
Large Scale ◽  
Biological Response ◽  
Tree Age ◽  
Local Effects ◽  
Vulnerability To Climate Change ◽  
Or Gene ◽  
Water Holding ◽  
Epiphyte Community

AbstractThere is growing evidence that species and communities are responding to, and will continue to be affected by, climate change. For species at risk, vulnerability can be reduced by ensuring that their habitat is extensive, connected and provides opportunities for dispersal and/or gene flow, facilitating a biological response through migration or adaptation. For woodland epiphytes, vulnerability might also be reduced by ensuring sufficient habitat heterogeneity, so that microhabitats provide suitable local microclimates, even as the larger scale climate continues to change (i.e. microrefugia). This study used fuzzy set ordination to compare bryophyte and lichen epiphyte community composition to a large-scale gradient from an oceanic to a relatively more continental macroclimate. The residuals from this relationship identified microhabitats in which species composition reflected a climate that was more oceanic or more continental than would be expected given the prevailing macroclimate. Comparing these residuals to features that operate at different scales to create the microclimate (landscape, stand and tree-scale), it was possible to identify how one might engineer microrefugia into existing or new woodland, in order to reduce epiphyte vulnerability to climate change. Multimodel inference was used to identify the most important features for consideration, which included local effects such as height on the bole, angle of bole lean and bark water holding capacity, as well as tree species and tree age, and within the landscape, topographic wetness and physical exposure.

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 Lianas reduce carbon accumulation and storage in tropical forests

2015 ◽  
Vol 112 (43) ◽  
pp. 13267-13271 ◽  
Author(s):  
Geertje M. F. van der Heijden ◽  
Jennifer S. Powers ◽  
Stefan A. Schnitzer
Keyword(s):  
Tropical Forests ◽  
Large Scale ◽  
Net Primary Production ◽  
Carbon Dynamics ◽  
Carbon Accumulation ◽  
Carbon Uptake ◽  
Woody Vines ◽  
Significant Difference ◽  
Agent Of Change ◽  
The Impact

Tropical forests store vast quantities of carbon, account for one-third of the carbon fixed by photosynthesis, and are a major sink in the global carbon cycle. Recent evidence suggests that competition between lianas (woody vines) and trees may reduce forest-wide carbon uptake; however, estimates of the impact of lianas on carbon dynamics of tropical forests are crucially lacking. Here we used a large-scale liana removal experiment and found that, at 3 y after liana removal, lianas reduced net above-ground carbon uptake (growth and recruitment minus mortality) by ∼76% per year, mostly by reducing tree growth. The loss of carbon uptake due to liana-induced mortality was four times greater in the control plots in which lianas were present, but high variation among plots prevented a significant difference among the treatments. Lianas altered how aboveground carbon was stored. In forests where lianas were present, the partitioning of forest aboveground net primary production was dominated by leaves (53.2%, compared with 39.2% in liana-free forests) at the expense of woody stems (from 28.9%, compared with 43.9%), resulting in a more rapid return of fixed carbon to the atmosphere. After 3 y of experimental liana removal, our results clearly demonstrate large differences in carbon cycling between forests with and without lianas. Combined with the recently reported increases in liana abundance, these results indicate that lianas are an important and increasing agent of change in the carbon dynamics of tropical forests.

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.

scholarly journals On the Shoulders of Giants: Continuing the Legacy of Large-Scale Ecosystem Manipulation Experiments in Puerto Rico

Forests ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 210 ◽  
Author(s):  
Tana Wood ◽  
Grizelle González ◽  
Whendee Silver ◽  
Sasha Reed ◽  
Molly Cavaleri
Keyword(s):  
Puerto Rico ◽  
Tropical Forests ◽  
Large Scale ◽  
Field Experiments ◽  
Management Strategies ◽  
Luquillo Experimental Forest ◽  
Hurricane Disturbance ◽  
Wide Range ◽  
History Of ◽  
Forest Function

There is a long history of experimental research in the Luquillo Experimental Forest in Puerto Rico. These experiments have addressed questions about biotic thresholds, assessed why communities vary along natural gradients, and have explored forest responses to a range of both anthropogenic and non-anthropogenic disturbances. Combined, these studies cover many of the major disturbances that affect tropical forests around the world and span a wide range of topics, including the effects of forest thinning, ionizing radiation, hurricane disturbance, nitrogen deposition, drought, and global warming. These invaluable studies have greatly enhanced our understanding of tropical forest function under different disturbance regimes and informed the development of management strategies. Here we summarize the major field experiments that have occurred within the Luquillo Experimental Forest. Taken together, results from the major experiments conducted in the Luquillo Experimental Forest demonstrate a high resilience of Puerto Rico’s tropical forests to a variety of stressors.

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.

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