scholarly journals Effect of Gap Size And Elevation On The Regeneration And Coexistence of Three Tree Species In A Subalpine Coniferous Forest

2021 ◽  
Author(s):  
Wangya Han ◽  
Li Chen ◽  
G. Geoff Wang ◽  
Dan Liu ◽  
Guohua Liu
Keyword(s):  
Community Assembly ◽  
Tree Species ◽  
Species Coexistence ◽  
Elevation Gradient ◽  
Coniferous Forest ◽  
Photon Flux ◽  
Gap Size ◽  
Stem Size ◽  
Subalpine Coniferous Forest ◽  
Old Growth Forest

Abstract Background: Gap size and environmental gradient have fundamental influence on the tree species coexistence and community assembly. We studied the regeneration and coexistence of three co-dominant tree species in three different gap size (large gap, 201-402 m2; medium gap, 101-200 m2; small gap, 38.8-100 m2) along an elevation gradient (between 3000m and 3500m) in an old-growth forest, on Mount Nadu in southwest China. Results: We found that the photosynthetic photon flux density (PPFD) was positively affected by gap size during the growing season. All three species had a higher regeneration density in large gaps, but the detailed response to treatments for each species depended on its stem size. Gap size had a significant positive effect on the regeneration density of Abies faxoniana small trees and Betula utilis saplings, but had no significant effect on Acer maximowiczii regeneration density. Saplings regeneration density is more sensitive to elevation compared to small trees regeneration density. Large gaps magnified the negative effects of elevation on regeneration density. Our findings indicated that Abies may maintain its regeneration advantage with low-intensity canopy disturbance, and large gap may provide excellent opportunities for broadleaf species (Betula and Acer) establishment and regeneration in this subalpine coniferous forest. Conclusion: Microhabitats heterogeneity controlled by characteristics of forest gaps along an elevation affected regeneration niche difference of tree species, which contributed to species coexistence and community assembly processes.

Small-scale disturbance in a northern hardwoods forest: effects on tree species abundance and distribution

1993 ◽  
Vol 23 (7) ◽  
pp. 1347-1360 ◽  
Author(s):  
Jan W. McClure ◽  
Thomas D. Lee
Keyword(s):  
Tree Species ◽  
Species Abundance ◽  
Root Competition ◽  
Northern Hardwoods ◽  
Soil Conditions ◽  
Small Scale ◽  
Gap Size ◽  
Old Growth Forest ◽  
Tolerant Species ◽  
Shade Tolerant Species

Sampling of 24-, 34-, and 44-year-old patch cuts (324–2400 m2) in the Bartlett Experimental Forest, New Hampshire, was undertaken to assess the effect of gap size and location within a gap on tree species abundance (relative basal area and relative density). Shade-tolerant species, especially eastern hemlock (Tsugacanadensis (L.) Carr.) and American beech (Fagusgrandifolia Ehrh.), were relatively more abundant in small gaps and gap edges and generally decreased with increasing gap size. Shade-intolerant species, including paper birch (Betulapapyrifera Marsh.) and pin cherry (Prunuspensylvanica L.f.), were relatively more abundant in large gaps and gap centers and increased with increasing gap size. Intermediately shade-tolerant species, especially yellow birch (Betulaalleghaniensis Britt.) and red maple (Acerrubrum L.), were relatively more abundant in gap centers. Striped maple (Acerpensylvanicum L.) was relatively more abundant in gap edges. Many of these relationships were complex due to interactions with gap age and slope. Sugar maple (Acersaccharum Marsh.) relative abundance was not associated with gap size or location within a gap. Analyses isolating irradiance as a factor influencing species composition were inconclusive. Instead, other effects of gap disturbance and characteristics associated with different locations in the gap, such as soil conditions and root competition, may play an important role in the gap dynamics of this northern hardwoods forest. Gap age had a strong effect on species relative abundances and these patterns reflected typical successional sequences in northern hardwood forests. The gap disturbances increased species richness and diversity in this forest. Gaps contained species not present in the old-growth forest, and the species compositional variations among different gap sizes suggest that a forest with a range of gap sizes will have high diversity. Competitive exclusion appeared to be prevented by the gap disturbances, a likely consequence of the release of previously unavailable resources.

scholarly journals Canopy gaps and tree regeneration patterns in multi-species unmanaged natural forest Sitno (preliminary results)

Beskydy ◽  
2013 ◽  
Vol 6 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Lucia Danková ◽  
M. Saniga
Keyword(s):  
Tree Species ◽  
Natural Regeneration ◽  
Canopy Gaps ◽  
Tree Regeneration ◽  
Acer Pseudoplatanus ◽  
Gap Size ◽  
Acer Platanoides ◽  
Large Variability ◽  
Old Growth Forest ◽  
Closed Canopy

The study of canopy gaps structure and tree regeneration patterns was conducted in mixed old-growth forest Sitno. We asked the following questions: What is the spatial scale of disturbance events? How does gap size affect the density of tree seedlings and saplings? Are there any differences in species composition of seedlings and saplings between the closed canopy and expanded gap? The research was conducted on a 2.5-ha (250 × 100 m) research plot. In total, 25 canopy openings were recorded. Canopy gaps and expanded gaps covered 22.8 % and 59.5 % of the research area. The most frequent were canopy gaps with the size up to 300 m2(64 %). Regarding the number of gapmakers, we recorded a quite large variability with the highest frequency of the gaps with 1 and 4 gapmakers. Regeneration structure (density and frequency) was sampled in 3.14 m2circular plot (n = 216) established on the grid intersections (10 × 10 m). A total of 8 tree species were identified in natural regeneration. The difference between overall density of natural regeneration under closed canopy and in expanded gaps was observed. The density of all tree species seedlings (except ofCarpinus betulus) was higher under closed canopy than in expanded gaps. The most frequent were seedlings ofAcer pseudoplatanusandAcer platanoideswhich occurred on 80 % and 73 % of the plots under closed canopy, and 75 % and 68 % of the plots in expanded gaps. Seedlings ofQuercus petraeawere not recorded. Density of saplings was higher in expanded gaps than under canopy (except of saplings ofAcer platanoidesandTilia cordata). The density of saplings ofAcer pseudoplatanusandAcer platanoidesincreased with increasing size of expanded gap, whileFraxinus excelsiorsaplings density decreased. There was no significant relationship between density of other species seedlings and saplings and expanded gap size.

scholarly journals Incorporating human behaviors into theories of urban community assembly and species coexistence

Oikos ◽  
2021 ◽  
Author(s):  
Meghan L. Avolio ◽  
Christopher Swan ◽  
Diane E. Pataki ◽  
G. Darrel Jenerette
Keyword(s):  
Community Assembly ◽  
Species Coexistence ◽  
Urban Community ◽  
Human Behaviors

scholarly journals Ecological drivers of avian community assembly along a tropical elevation gradient

Ecography ◽  
2020 ◽  
Author(s):  
Flavia A. Montaño‐Centellas ◽  
Bette A. Loiselle ◽  
Morgan W. Tingley
Keyword(s):  
Community Assembly ◽  
Elevation Gradient ◽  
Avian Community

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.

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