Dynamics of seedling populations and tree species coexistence in a forest: a simulation study

2006 ◽  
Vol 21 (3) ◽  
pp. 356-363 ◽  
Author(s):  
Akio Takenaka
Keyword(s):  
Simulation Study ◽  
Tree Species ◽  
Species Coexistence

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 Pulling on multiple threads of evidence to reveal tree species coexistence

2021 ◽  
Author(s):  
Gordon G McNickle ◽  
Morgan V Ritzi ◽  
Kliffi M.S. Blackstone ◽  
John J Couture ◽  
Taylor Nelson ◽  
...  
Keyword(s):  
Tree Species ◽  
Species Coexistence ◽  
Analysis Data ◽  
The United States ◽  
United States Department ◽  
Hardwood Species ◽  
Niche Differences ◽  
The Usa ◽  
Multiple Threads ◽  
Occurrence Patterns

Understanding drivers of species coexistence is a central challenge in ecology. Coexistence cannot be observed directly, and while species co-occurrence in time and space is necessary for coexistence, it is not sufficient to prove coexistence. Species exclusion from a region is potentially observable, but can take decades to occur, and still might occur stochastically. Thus, ecologists generally use theory to identify indirect observations that are indicative of mechanisms driving coexistence or exclusion. Various methods have been developed to indirectly infer coexistence, each of which requires different data, and none of which are usually conclusive on their own. Here, we demonstrate agreement using three different approaches examining coexistence of multiple hardwood species. First, in an experimental planting of three mature tree species we found no relationship between productivity and species diversity, which could be due to a lack of niche differences among species. Second, we used modern coexistence theory to calculate niche and fitness differences for each pair of species, which confirmed the lack of niche differences among species, and showed high fitness differences that could create a neutral distribution of species in nature. Third, we used the United States Department of Agriculture Forest Inventory and Analysis data to examine co-occurrence patterns of our species across thousands of natural forest stands and found that indeed, these three species were distributed randomly throughout the USA. Given that these independent methods agree, we take this as strong evidence about a lack of coexistence.

scholarly journals Modeling the Ecological Responses of Tree Species to the Flood Pulse of the Amazon Negro River Floodplains

2021 ◽  
Vol 9 ◽  
Author(s):  
John Ethan Householder ◽  
Jochen Schöngart ◽  
Maria T. F. Piedade ◽  
Wolfgang J. Junk ◽  
Hans ter Steege ◽  
...  
Keyword(s):  
Tree Species ◽  
Amazon Basin ◽  
Species Coexistence ◽  
Experimental Studies ◽  
Flood Pulse ◽  
Forest Composition ◽  
Compositional Variation ◽  
Flood Duration ◽  
Negro River ◽  
Ideal System

The large flood pulse of the Amazon basin is a principal driver of environmental heterogeneity with important implications for ecosystem function and the assembly of natural communities. Understanding species ecological response to the flood pulse is thus a key question with implications for theories of species coexistence, resource management, and conservation. Yet these remain largely undescribed for most species, and in particular for trees. The large flood pulse and high tree diversity of the Negro River floodplain makes it an ideal system to begin filling this knowledge gap. We merged historical hydrologic data with 41 forest inventories under variable flooding conditions distributed across the Negro River basin, comprising a total area of 34 ha, to (i) assess the importance of flood duration as a driver of compositional variation, (ii) model the response curve shapes of 111 of the most frequent tree species in function of flood duration, and (iii) derive their niche properties (optima and tolerance). We found that flood duration is a strong driver of compositional turnover, although the majority site-to-site variation in forest composition still remains unexplained. About 73% of species responded to the flood duration gradient, exhibiting a diversity of shapes, but most frequently skewed. About 29% of species were clearly favored by flood durations >120 days year–1, and 44% of species favored by shorter floods. The median niche breadth was 85 flood days year–1, corresponding to approximately 30% of the flood duration gradient. A significant subset of species (27%) did not respond to flooding, but rather exhibited wide tolerance to the flood gradient. The response models provided here offer valuable information regarding tree species differential capacity to grow, survive, and regenerate along an ecologically important gradient and are spatially valid for the Amazon Negro basin. These attributes make them an appealing tool with wide applicability for field and experimental studies in the region, as well as for vegetation monitoring and simulation models of floodplain forest change in the face of hydrologic alteration.

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.

scholarly journals Spatial distribution of four sympatric owl species in Carpathian montane forests

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Karol Šotnár ◽  
Ján Obuch ◽  
Samuel Pačenovský ◽  
Benjamín Jarčuška
Keyword(s):  
Spatial Distribution ◽  
Tree Species ◽  
Species Coexistence ◽  
Spatial Arrangement ◽  
Point Pattern Analysis ◽  
Stand Age ◽  
Point Pattern ◽  
Montane Forests ◽  
Aegolius Funereus ◽  
Coexistence Mechanisms

AbstractKnowledge about spatial distribution of owl species is important for inferring species coexistence mechanisms. In the present study, we explore spatial patterns of distribution and habitat selection of four owl species – Eurasian pygmy owl (Glaucidium passerinum), boreal owl (Aegolius funereus), tawny owl (Strix aluco) and Ural owl (Strix uralensis) – ranging in body mass from 50 g to 1300 g, with sympatric occurrence in temperate continuous montane forests in the Veľká Fatra Mts., Western Carpathians, central Slovakia. Locations of hooting owl males were surveyed between 2009–2015 in an area of 317 km2. Spatial point pattern analysis was used for analysis of owl distribution. Random patterns of owls’ spatial arrangement dominate at both intra‐ and interspecific levels within the studied area. Only intraspecific distribution of pygmy owls and interspecific distribution of Ural owls toward tawny owls exhibited positive associations. This discrepancy with other studies can be explained in terms of pygmy owls’ preference for high‐quality nest sites and/or spatial clustering in their prey distribution, and due to aggressive behaviour of dominant Ural owls toward subdominant tawny owls, respectively. Moreover, we found considerable overlap in habitat preferences between owl species, considering stand age, stand height, tree species richness, distance to open area, elevation, slope, percentage of coniferous tree species and position on hillslope, although pygmy owls were not registered in pure broadleaved stands, Ural owls were not registered in pure coniferous stands, and boreal and Ural owls were more common on slope summits and shoulders than tawny and pygmy owls. The observed patterns of spatial arrangement might suggest developed coexistence mechanisms in these owl species; differences between studies may indicate complex interactions between intra‐ and interspecific associations and habitat quality and quantity, food availability and owl species involved in those interactions on a landscape scale.

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