Topography related habitat associations of tree species traits, composition and diversity in a Chinese tropical forest

Tree death drives population dynamics, nutrient cycling, and evolution within plant communities. Mortality variation across species is thought to be influenced by different factors relative to variation within species. The unified model provided here separates mortality rates into growth-dependent and growth-independent hazards. This model creates the opportunity to simultaneously estimate these hazards both across and within species. Moreover, it provides the ability to examine how species traits affect growth-dependent and growth-independent hazards. We derive this unified mortality model using cross-validated Bayesian methods coupled with mortality data collected over three census intervals for 203 tropical rainforest tree species at Barro Colorado Island (BCI), Panama. We found that growth-independent mortality tended to be higher in species with lower wood density, higher light requirements, and smaller maximum diameter at breast height (dbh). Mortality due to marginal carbon budget as measured by near-zero growth rate tended to be higher in species with lower wood density and higher light demand. The total mortality variation attributable to differences among species was large relative to variation explained by these traits, emphasizing that much remains to be understood. This additive hazards model strengthens our capacity to parse and understand individual-level mortality in highly diverse tropical forests and hence to predict its consequences.

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Effect of disturbance on plant species abundance and density distribution in tropical forest of Sunsari district, Eastern Nepal

Nepalese Journal of Biosciences ◽

10.3126/njbs.v6i1.41761 ◽

2016 ◽

Vol 6 (1) ◽

pp. 1-12

Author(s):

Tilak Prasad Gautam ◽

Tej Narayan Mandal

Keyword(s):

Carbon Sequestration ◽

Species Composition ◽

Tropical Forest ◽

Tropical Forests ◽

Tree Species ◽

Forest Disturbance ◽

Species Abundance ◽

Forest Degradation ◽

Tree Density ◽

Shrub Species

The disappearance of global tropical forests due to deforestation and forest degradation has reduced the biodiversity and carbon sequestration capacity. In these contexts, present study was carried out to understand the species composition and density in the undisturbed and disturbed stands of moist tropical forest located in Sunsari district of eastern Nepal. Study revealed that the forest disturbance has reduced the number of tree species by 33% and tree density by 50%. In contrary, both number and density of herb and shrub species have increased with forest disturbance.

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Plant Diversity, Ethnobotany and Conservation Issues at Swoyambhu World Heritage, Kathmandu, Nepal

Nepal Journal of Science and Technology ◽

10.3126/njst.v7i0.583 ◽

2007 ◽

Vol 7 ◽

pp. 123 ◽

Cited By ~ 1

Author(s):

Keshab Shrestha

Keyword(s):

Tropical Forest ◽

Exotic Species ◽

Plant Species ◽

Plant Diversity ◽

Tree Species ◽

Human Population ◽

Northern Slope ◽

Pinus Roxburghii ◽

Total Plant ◽

Pristine Forest

Lying at western corner of the Kathmandu city, the Swoyambhu hillock (1403.76m) represents a surviving pristine forest in the metropolitan capital of Nepal. Once an extension of Jamaca (2096m) with luxuriant sub-tropical forest is now invaded by dense human population and other developmental activities. This hillock is still rich with a total plant species of 319. Of them, 65 are trees, 43 shrubs, 194 herbs and 17 climbers. Northern slope of the hillock is rich in tree species with scattered patches of under-growing bushes and ferns, whereas southern, western and eastern slopes are much disturbed with exotic species of plants, creating challenges to the norms of the heritage standard. Domination by Pinus roxburghii (chire pine) and Eucalyptus, Jacaranda and Callistemon, etc are altering the indigenous nature of the hillock. And also the forested hillock has been randomly utilized for refreshment, yoga, ayurbedic remedy and food. Due to growing constructions and exploitations, the forested hillock is now facing a threat to maintain its pristine ecosystem. <i>Nepal Journal of Science and Technology</i> Vol. 7, 2006

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Population Structures of Four Tree Species in Loggpopulation Structures of Four Tree Species in Logged-Over Tropical Forest in South Papua, Indonesia: an Integral Projection Model Approach

Indonesian Journal of Forestry Research ◽

10.20886/ijfr.2015.2.2.93-101 ◽

2015 ◽

Vol 2 (2) ◽

pp. 93-101

Author(s):

Relawan Kuswandi ◽

Agustinus Murdjoko

Keyword(s):

Tropical Forest ◽

Tree Species ◽

Integral Projection Model ◽

Projection Model ◽

Integral Projection ◽

Population Structures ◽

Model Approach

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Design and Statistical Issues Related to Habitat Analysis

Habitat Ecology and Analysis ◽

10.1093/oso/9780198829287.003.0007 ◽

2021 ◽

pp. 95-116

Author(s):

Joseph A. Veech

Keyword(s):

Count Data ◽

Detection Probability ◽

Spatial Dispersion ◽

Species Traits ◽

Habitat Associations ◽

Statistical Techniques ◽

Focal Species ◽

Habitat Analysis ◽

Background Density ◽

Statistical Issues

There are many different design and statistical issues that a researcher should consider when developing the data collection protocol or when interpreting results from a habitat analysis. One of the first considerations is simply the area to include in the study. This depends on the behavior (particularly mobility) of the focal species and logistical constraints. The amount of area also relates to the number of survey locations (plots, transects, or other) and their spatial placement. Survey data often include many instances of a species absent from a spatial sampling unit. These could be true absences or might represent very low species detection probability. There are different statistical techniques for estimating detection probability as well as analyzing data with a substantial proportion of zero-abundance values. The spatial dispersion of the species within the overall study area or region is never random. Even apart from the effect of habitat, individuals are often aggregated due to various environmental factors or species traits. This can affect count data collected from survey plots. Related to spatial dispersion, the overall background density of the species within the study area can introduce particular challenges in identifying meaningful habitat associations. Statistical issues such as normality, multicollinearity, spatial and temporal autocorrelation may be relatively common and need to be addressed prior to an analysis. None of these design and statistical issues presents insurmountable challenges to a habitat analysis.

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