Demography and biomass change in monodominant and mixed old-growth forest of the Congo

2011 ◽  
Vol 27 (5) ◽  
pp. 447-461 ◽  
Author(s):  
Jean-Remy Makana ◽  
Corneille N. Ewango ◽  
Sean M. McMahon ◽  
Sean C. Thomas ◽  
Terese B. Hart ◽  
...  
Keyword(s):  
Tree Mortality ◽  
Community Dynamics ◽  
Mixed Forest ◽  
Common Species ◽  
Forest Change ◽  
Old Growth Forest ◽  
Stock Biomass ◽  
Sapling Density ◽  
And Shifts ◽  
Ituri Forest

Abstract:Mbau forest covers much of the Congo, and shifts in its composition could have a large impact on the African tropics. The Ituri forest in east Congo is near a boundary between the monodominant mbau type and non-mbau mixed forest, and two 20-ha censuses of trees ≥ 1 cm diameter were carried out over 12 y to monitor forest change. Based on published diameter allometry, mbau forest had 535 Mg ha−1 biomass above ground and gained 1.1 Mg ha−1 y−1. Mixed forest had 399 Mg ha−1 and gained 3 Mg ha−1 y−1. The mbau tree (Gilbertiodendron dewevrei) increased its share of biomass from 4.1% to 4.4% in mixed forest; other common species also increased. Sapling density declined at both sites, likely because increased biomass meant shadier understorey, but the mbau tree increased in sapling density, suggesting it will become more important in the future. Tree mortality and growth rates were low relative to other tropical forests, especially in the mbau plots. Shifting toward G. dewevrei would represent a large gain in carbon in the mixed forest, but mbau is presently more important as a high-carbon stock: biomass lost during forest harvest could not recuperate for centuries due to slow community dynamics.

Community dynamics of a montane Fagus engleriana–Cyclobalanopsis multiervis mixed forest in Shennongjia, Hubei, China

2013 ◽  
Vol 20 (6) ◽  
pp. 643-653
Author(s):  
Ge Jielin ◽  
Xiong Gaoming ◽  
Deng Longqiang ◽  
Zhao Changming ◽  
Shen Guozhen ◽  
...  
Keyword(s):  
Community Dynamics ◽  
Mixed Forest ◽  
Fagus Engleriana

A Social-Ecological Analysis of Urban Tree Vulnerability for Publicly Owned Trees in a Residential Neighborhood

2019 ◽  
Vol 45 (1) ◽  
Author(s):  
James Steenberg ◽  
Andrew Millward ◽  
David Nowak ◽  
Pamela Robinson ◽  
Sandy Smith
Keyword(s):  
Tree Mortality ◽  
Urban Forest ◽  
Spatial Scales ◽  
Bivariate Analysis ◽  
Land Uses ◽  
Forest Change ◽  
Social Ecological Systems ◽  
Residential Neighborhood ◽  
Social Ecological ◽  
Vulnerability Indicators

The urban forest is a valuable ecosystem service provider, yet cities are frequently degraded environments with a myriad of stressors and disturbances affecting trees. Vulnerability science is increasingly used to explore issues of sustainability in complex social-ecological systems, and can be a useful approach for assessing urban forests. The purpose of this study was to identify and explore drivers of urban forest vulnerability in a residential neighborhood. Based on a recently published framework of urban forest vulnerability, a series of indicators of exposure, sensitivity, and adaptive capacity that describe the built environment, urban forest structure, and human population, respectively, were assessed for 806 trees in Toronto, Ontario, Canada. Tree mortality, condition, and diameter growth rates were then assessed using an existing 2007/2008 inventory. A bivariate analysis was first conducted to test for significant relationships of vulnerability indicators with mortality, condition, and growth. A multivariate analysis was then conducted using multiple linear regression for the continuous condition and growth variables and a multilayer perceptron neural network for the binary mortality variable. Commercial land uses and commercial buildings adjacent to trees consistently explained higher mortality rates and poor tree conditions. However, at finer spatial scales it is important to differentiate between different causes and correlates of urban forest decline within commercial land uses. Tree species, size, and condition were also important indicators of vulnerability. Understanding the causes of urban forest change and decline are essential for developing planning strategies to reduce long-term system vulnerability.

scholarly journals Understanding long-term primate community dynamics: implications of forest change

2010 ◽  
Vol 20 (1) ◽  
pp. 179-191 ◽  
Author(s):  
Colin A. Chapman ◽  
Thomas T. Struhsaker ◽  
Joseph P. Skorupa ◽  
Tamaini V. Snaith ◽  
Jessica M. Rothman
Keyword(s):  
Community Dynamics ◽  
Forest Change ◽  
Primate Community

Consequences for ectomycorrhizal fungi of the selective loss or gain of pine across landscapes

Botany ◽  
2014 ◽  
Vol 92 (12) ◽  
pp. 855-865 ◽  
Author(s):  
Justine Karst ◽  
Morgan J. Randall ◽  
Catherine A. Gehring
Keyword(s):  
Community Composition ◽  
Tree Mortality ◽  
Ecosystem Processes ◽  
The Other ◽  
Fungal Communities ◽  
Individual Tree ◽  
Disturbance Regimes ◽  
Fungal Abundance ◽  
The Individual ◽  
And Shifts

Altered disturbance regimes and novel introductions are causing rapid shifts in the distribution of pines (Pinus L.). The functionally obligate symbiosis between pines and ectomycorrhizal (EM) fungi dictates that shifts in the distribution of one partner will affect the distribution of the other. In this review, we examine evidence for three hypotheses. (1) The loss of photosynthates through stress or tree mortality decreases the abundance of EM fungi and selects for less carbon-demanding species. (2) Pine introductions initiate establishment of novel EM fungal communities. (3) The extent of shifts in EM fungal abundance and community composition is mediated by surrounding vegetation. We find support for these hypotheses though changes in EM fungal abundance are variable and context-dependent. We posit that the consequences of shifts in EM fungal abundance and community composition extend beyond the individual tree to the landscape; these changes may affect population dynamics of both symbionts, ecosystem processes, and the conservation and evolution of fungi. In addition to conducting baseline surveys to assess the distribution of EM fungi, increasing our understanding of their function, morphology, propagation, and controls on host-specificity, and shifts would also assist in predicting the trajectory of ecosystems following the loss or gain of pine.

scholarly journals Ecosystem Resilience and Limitations Revealed by Soil Bacterial Community Dynamics in a Bark Beetle-Impacted Forest

mBio ◽  
2017 ◽  
Vol 8 (6) ◽  
Author(s):  
Kristin M. Mikkelson ◽  
Brent M. Brouillard ◽  
Chelsea M. Bokman ◽  
Jonathan O. Sharp
Keyword(s):  
Water Quality ◽  
Bacterial Community ◽  
Tree Mortality ◽  
Community Dynamics ◽  
Watershed Scale ◽  
Microbial Community Dynamics ◽  
Local Soil ◽  
The World ◽  
Water Quality And Quantity ◽  
Insight Into

ABSTRACT Forested ecosystems throughout the world are experiencing increases in the incidence and magnitude of insect-induced tree mortality with large ecologic ramifications. Interestingly, correlations between water quality and the extent of tree mortality in Colorado montane ecosystems suggest compensatory effects from adjacent live vegetation that mute responses in less severely impacted forests. To this end, we investigated whether the composition of the soil bacterial community and associated functionality beneath beetle-killed lodgepole pine was influenced by the extent of surrounding tree mortality. The most pronounced changes were observed in the potentially active bacterial community, where alpha diversity increased in concert with surrounding tree mortality until mortality exceeded a tipping point of ~30 to 40%, after which diversity stabilized and decreased. Community structure also clustered in association with the extent of surrounding tree mortality with compositional trends best explained by differences in NH4 + concentrations and C/N ratios. C/N ratios, which were lower in soils under beetle-killed trees, further correlated with the relative abundance of putative nitrifiers and exoenzyme activity. Collectively, the response of soil microorganisms that drive heterotrophic respiration and decay supports observations of broader macroscale threshold effects on water quality in heavily infested forests and could be utilized as a predictive mechanism during analogous ecosystem disruptions. IMPORTANCE Forests around the world are succumbing to insect infestation with repercussions for local soil biogeochemistry and downstream water quality and quantity. This study utilized microbial community dynamics to address why we are observing watershed scale biogeochemical impacts from forest mortality in some impacted areas but not others. Through a unique “tree-centric” approach, we were able to delineate plots with various tree mortality levels within the same watershed to see if surviving surrounding vegetation altered microbial and biogeochemical responses. Our results suggest that forests with lower overall tree mortality levels are able to maintain “normal” ecosystem function, as the bacterial community appears resistant to tree death. However, surrounding tree mortality influences this mitigating effect with various linear and threshold responses whereupon the bacterial community and its function are altered. Our study lends insight into how microscale responses propagate upward into larger-scale observations, which may be useful for future predictions during analogous disruptions. IMPORTANCE Forests around the world are succumbing to insect infestation with repercussions for local soil biogeochemistry and downstream water quality and quantity. This study utilized microbial community dynamics to address why we are observing watershed scale biogeochemical impacts from forest mortality in some impacted areas but not others. Through a unique “tree-centric” approach, we were able to delineate plots with various tree mortality levels within the same watershed to see if surviving surrounding vegetation altered microbial and biogeochemical responses. Our results suggest that forests with lower overall tree mortality levels are able to maintain “normal” ecosystem function, as the bacterial community appears resistant to tree death. However, surrounding tree mortality influences this mitigating effect with various linear and threshold responses whereupon the bacterial community and its function are altered. Our study lends insight into how microscale responses propagate upward into larger-scale observations, which may be useful for future predictions during analogous disruptions.

scholarly journals Studying vertical microbiome transmission from mothers to infants by strain-level metagenomic profiling

2016 ◽  
Author(s):  
Francesco Asnicar ◽  
Serena Manara ◽  
Moreno Zolfo ◽  
Duy Tin Truong ◽  
Matthias Scholz ◽  
...  
Keyword(s):  
Vertical Transmission ◽  
Gut Microbiome ◽  
Community Dynamics ◽  
Infant Health ◽  
Common Species ◽  
Strain Level ◽  
Metagenomic Sequencing ◽  
Shotgun Metagenomics ◽  
Early Infant

AbstractThe gut microbiome starts to be shaped in the first days of life and continues to increase its diversity during the first months. Several investigations are assessing the link between the configuration of the infant gut microbiome and infant health, but a comprehensive strain-level assessment of vertically transmitted microbes from mother to infant is still missing. We longitudinally collected fecal and breast milk samples from multiple mother-infant pairs during the first year of life, and applied shotgun metagenomic sequencing followed by strain-level profiling. We observed several specific strains including those from Bifidobacterium bifidum, Coprococcus comes, and Ruminococcus bromii, that were present in samples from the same mother-infant pair, while being clearly distinct from those carried by other pairs, which is indicative of vertical transmission. We further applied metatranscriptomics to study the in vivo expression of vertically transmitted microbes, for example Bacteroides vulgatus and Bifidobacterium spp., thus suggesting that transmitted strains are functionally active in the two rather different environments of the adult and infant guts. By combining longitudinal microbiome sampling and newly developed computational tools for strain-level microbiome analysis, we showed that it is possible to track vertical transmission of members of the microbiome from mother to infants and characterize their transcriptional activity. Our work poses the basis for surveying at larger scale the sources of microbial diversity in the infants and starts associating these transmissions with the subsequent longer-term development of a healthy or dysbiotic microbiome.ImportanceEarly infant exposure is important in the acquisition and ultimate development of a healthy infant microbiome. There is increasing support that the maternal microbial reservoir is a key route of microbial transmission, yet much is inferred from the observation of shared species in mother and infant. Common species, per se, does not necessarily equate vertical transmission as species exhibit considerable strain heterogeneity and it is therefore imperative to identify shared strains. We demonstrate here the potential of shotgun metagenomics and strain-level resolution to identify vertical transmission events via the maternal source. Combined with a metatranscriptomic approach, we show the potential not only to identify and track the fate of microbes in the early infant microbiome but also identify the metabolically active members. These approaches will ultimately provide important insights into the acquisition, development and community dynamics of the infant microbiome.

Helminths of the Mallard, Anas Platyrhynchos (Aves, Anatidae), in Ukraine: Analysis of the Diversity in Mixed Forest Zone and the Black Sea Region

2018 ◽  
Vol 52 (4) ◽  
pp. 267-278 ◽  
Author(s):  
Ya. Yu. Syrota ◽  
O. B. Greben ◽  
A. M. Poluda ◽  
O. M. Maleha ◽  
O. I. Lisitsyna ◽  
...  
Keyword(s):  
Black Sea ◽  
Mixed Forest ◽  
Nematode Species ◽  
Common Species ◽  
The Black Sea ◽  
Trematode Species ◽  
Forest Zone ◽  
Black Sea Region ◽  
Echinostoma Revolutum ◽  
High Level

Abstract Thirty-eight Mallards were collected on the territory of Ukrainian Polissia to study the fauna of their gastro-intestinal helminths. Materials were collected in 1998-2000, 2014 and 2016 on the territory of Volyn and Chernihiv Regions. In total, 33 species of helminths were found. Th e prevalence of cestode infection was 78.9 %. We found 18 cestode species: Aploparaksis furcigera, Cloacotaenia megalops, Dicranotaenia coronula, Diorchis acuminatus, D. stefanskii, Fimbriaria fasciolaris, F. teresae, Microsomacanthus compressa, M. spiralibursata, M. paracompressa, M. paramicrosoma, M. parvula, M. hopkinsi, Platyscolex ciliata, Retinometra venusta, Sobolevicanthus aculeostyleticus, S. gracilis, S. stolli. Th e prevalence of trematode infection was 73.7 %. Th ere were 10 trematode species: Bilharziella polonica, Apatemon gracilis, Echinoparyphium aconitum, E. cinctum, Echinostoma revolutum group, Hypoderaeum conoideum, Notocotylus attenuatus, Parastrigea robusta, Prosthogonimus ovatus, P. cuneatus.Th e prevalence of nematode infection was 7.9 %. Th ere were four nematode species: Capillaria anatis, Capillariidae gen. sp., Eucoleus contorta, Tetrameres fi ssispina. Th e prevalence of an acanthocephalan Filicollis anatis was 18.4 %. Th e most common species of helminths were A. furcigera, B. polonica, A. gracilis, Echinostoma revolutum group, F. fasciolaris, H. conoideum. Th e helminth faunas of Mallards from the territory of Ukrainian Polissia and from the Black Sea Region of Ukraine were compared. Th e results of comparison demonstrated a high level of their qualitative similarity.

MIOCENE NERITIC BENTHIC FORAMINIFERAL COMMUNITY DYNAMICS, CALVERT CLIFFS, MARYLAND, USA: SPECIES POOL, PATTERNS AND PROCESSES

Palaios ◽  
2021 ◽  
Vol 36 (7) ◽  
pp. 247-259
Author(s):  
STEPHEN J. CULVER ◽  
SETH R. SUTTON ◽  
DAVID J. MALLINSON ◽  
MARTIN A. BUZAS ◽  
MARCI M. ROBINSON ◽  
...  
Keyword(s):  
Sea Level ◽  
Benthic Foraminifera ◽  
Middle Miocene ◽  
Community Dynamics ◽  
Abundant Species ◽  
Common Species ◽  
Species Pool ◽  
Regional Species Pool ◽  
Patterns And Processes ◽  
Climate Transition

ABSTRACT The presence/absence and abundance of benthic foraminifera in successive discrete beds (Shattuck “zones”) of the Miocene Calvert and Choptank formations, exposed at the Calvert Cliffs, Maryland, USA, allows for investigation of community dynamics over space and time. The stratigraphic distribution of benthic foraminifera is documented and interpreted in the context of sea-level change, sequence stratigraphy, and the previously published distribution of mollusks. Neritic benthic foraminiferal communities of four sea-level cycles over ∼4 million years of the middle Miocene, encompassing the Miocene Climatic Optimum and the succeeding middle Miocene Climate Transition, are dominated by the same abundant species. They differ in the varying abundance of common species that occur throughout most of the studied section and in the different rare species that appear and disappear. Transgressive systems tracts (TSTs) have higher species diversity than highstand systems tracts (HSTs) but much lower density of specimens. In contrast to some previous research, all beds in the studied section are interpreted as being from the inner part of a broad, low gradient shelf and were deposited at water depths of less than ∼50 m. It is suggested that species are recruited from a regional species pool of propagules throughout the duration of TSTs. Recruitment is curtailed during highstands leading to lower diversity in the HSTs.

Forest disturbance frequency and patch structure from pre-European settlement to present in the Mixed Forest Province of Minnesota, USA

2008 ◽  
Vol 38 (8) ◽  
pp. 2212-2226 ◽  
Author(s):  
M. A. White ◽  
G. E. Host
Keyword(s):  
Spatial Pattern ◽  
Tree Mortality ◽  
Management Practices ◽  
Forest Disturbance ◽  
Mixed Forest ◽  
Strong Relationship ◽  
Timber Harvest ◽  
Study Region ◽  
Disturbance Frequency ◽  
Disturbance Factor

We used General Land Office survey data (1860–1890) and interpreted aerial photography from the 1930s, 1970s, and 1990s to quantify forest disturbance frequency and spatial patterns for four time periods in the Mixed Forest Province of Minnesota. The study region included eight subsections within the Mixed Forest Province of Minnesota’s Ecological Classification System. Presettlement disturbance and spatial pattern estimates varied across the eight subsections indicating a strong relationship to soil and landform characteristics. Land surveyors primarily recorded higher severity disturbances that resulted in significant tree mortality. The 1900–1940 era was characterized by a short-term increase in fire frequency that was relatively uniform across the study region, in contrast to the variability of the presettlement (1860–1890) landscape. In the postsettlement period (1940–1995), timber harvest replaced fire as the dominant disturbance factor. Similar management practices among subsections created similar harvest rates throughout the study region. These management practices imposed a more homogeneous pattern dominated by small (10–25 ha) patches. Management practices now have a greater influence than natural processes in the generation of landscape pattern in the Mixed Forest Province of Minnesota. Information on presettlement forest conditions and subsequent changes can be used by land managers to restore spatial pattern variability in managed forest landscapes.

Elevated mortality of residual trees following single-tree felling in northern hardwood forests

2006 ◽  
Vol 36 (5) ◽  
pp. 1255-1265 ◽  
Author(s):  
John P Caspersen
Keyword(s):  
Tree Mortality ◽  
Community Dynamics ◽  
Stand Structure ◽  
Hardwood Forests ◽  
Natural Mortality ◽  
Northern Hardwood Forests ◽  
Substantial Impact ◽  
Northern Hardwood ◽  
Single Tree

In this paper, I examine tree mortality in northern hardwood forests subjected to single-tree felling. Mortality risk was estimated as a function of growth prior to harvest and time since harvest. This allowed me to separately quantify mortality due to (1) natural processes, (2) intentional felling, and (3) stress and (or) felling damage (postcut mortality). The long-term rate of mortality due to natural causes was 1.5% per year. The intentional felling of trees increased the average mortality to 3.1%, and postcut mortality of residual trees increased the average an additional 0.2%–3.3% (the latter reflects both the direct negative effects of harvesting and the indirect positive effect of releasing residual trees from suppression). Thus, from a population-level perspective, the increased mortality caused by stress and (or) felling damage to residual trees was small compared to that caused by both natural mortality and tree felling. However, the long-term population average obscures more dramatic (though transient) effects of felling on small trees (DBH <10 cm), for which mortality rates increased by as much as 5% immediately after felling. This increase is several times greater than the natural mortality rate for small trees and may therefore have a substantial impact on stand structure and community dynamics.

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