scholarly journals A Bayesian Inference Procedure for structural characterization of Nigerian Tropical Forest

Author(s):  
SEHINDE AKINBIOLA ◽  
Ayobami Salami ◽  
Olusegun Awotoye

Abstract The complexity of the tropical forest structure remains a challenge in forest physiognomy assessment, which is a crucial indicator of forest productivity with implications on the carbon cycle, biodiversity, and ecosystem services. The study assessed structural characteristics, described variability within forest stands, and estimated carbon stocks using simulation tools and tree modeling to focus on understanding and quantifying ecological relationships. The study discovered a site-specific wood density difference of 0.07g/cm3 compared with the generalized wood density for tropical forests by Food and Agricultural Organisation (FAO). Carbon stocks estimated with this site-specific wood density produced; 174 Mg Ca / ha-1, 155 Mg Ca / ha-1, and 78 Mg Ca / ha-1, respectively, from three sampled Forest Reserves. Furthermore, the result showed that the forest clusters' most productive layers (emergent and canopy layers) were predominantly hardwood species interspersed with softwood species with huge diameters. The height-diameter model indicated that although the height was a better predictor of the forest structural layer than the diameter, there was no clear margin for grouping species into layers in the region because of interspecies variations, temperature, and anthropogenic activities. The Bayesian Inference procedure provided a reliable approach for carbon stock estimate in the tropics with no legacy inventories.

Author(s):  
Mae Flor G Posadas

Tropical rain forests are viable economic resources for people and their surrounding communities for they serve as sources of food and other materials. This descriptive research provides baseline information that describes and analyzes the socio-economic characteristics of human communities within the three forest patches of Sipalay City and the impact of their activities on these forest reserves. Quantitative and qualitative approaches were employed using survey, ethnobiology workshops, focus group discussions, and key informant interview methods to selected respondents living in these forests. Majority of the households that were natives and lived within the watershed reservation areas relied on farming and live below the poverty threshold due to lack of education, poor road network, and poor access to electricity and communication. Hence, forest areas were utilized in planting crops to support respondents’ meager incomes. Hunting, illegal logging, charcoal making, mining, dumping of garbage within the reservation, cutting of trees for firewood, kaingin/slash and burn system and human settlements were some of the anthropogenic activities that adversely affected the reservation and contributed to the decrease of vegetation, forest cover, and floral and faunal resources of Sipalay Forest Reserves. Given the situation, majority of the human communities living within the tropical forest were still willing to join programs that protect the remaining forest patches in Sipalay. Findings served as bases for identification of appropriate interventions for the management and development of the area.


Ecosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
Author(s):  
Samantha J. Worthy ◽  
Vanessa E. Rubio ◽  
Kirstin Staiger ◽  
Boris Ngouajio ◽  
Jie Yang ◽  
...  

2016 ◽  
Vol 13 (5) ◽  
pp. 1571-1585 ◽  
Author(s):  
Pierre Ploton ◽  
Nicolas Barbier ◽  
Stéphane Takoudjou Momo ◽  
Maxime Réjou-Méchain ◽  
Faustin Boyemba Bosela ◽  
...  

Abstract. Accurately monitoring tropical forest carbon stocks is a challenge that remains outstanding. Allometric models that consider tree diameter, height and wood density as predictors are currently used in most tropical forest carbon studies. In particular, a pantropical biomass model has been widely used for approximately a decade, and its most recent version will certainly constitute a reference model in the coming years. However, this reference model shows a systematic bias towards the largest trees. Because large trees are key drivers of forest carbon stocks and dynamics, understanding the origin and the consequences of this bias is of utmost concern. In this study, we compiled a unique tree mass data set of 673 trees destructively sampled in five tropical countries (101 trees > 100 cm in diameter) and an original data set of 130 forest plots (1 ha) from central Africa to quantify the prediction error of biomass allometric models at the individual and plot levels when explicitly taking crown mass variations into account or not doing so. We first showed that the proportion of crown to total tree aboveground biomass is highly variable among trees, ranging from 3 to 88 %. This proportion was constant on average for trees < 10 Mg (mean of 34 %) but, above this threshold, increased sharply with tree mass and exceeded 50 % on average for trees  ≥  45 Mg. This increase coincided with a progressive deviation between the pantropical biomass model estimations and actual tree mass. Taking a crown mass proxy into account in a newly developed model consistently removed the bias observed for large trees (> 1 Mg) and reduced the range of plot-level error (in %) from [−23; 16] to [0; 10]. The disproportionally higher allocation of large trees to crown mass may thus explain the bias observed recently in the reference pantropical model. This bias leads to far-from-negligible, but often overlooked, systematic errors at the plot level and may be easily corrected by taking a crown mass proxy for the largest trees in a stand into account, thus suggesting that the accuracy of forest carbon estimates can be significantly improved at a minimal cost.


2020 ◽  
Vol 9 ◽  
pp. 1-19
Author(s):  
Valentina Gnisci ◽  
Selvaggia Cognetti de Martiis ◽  
Alessandro Belmonte ◽  
Carla Micheli ◽  
Viviana Piermattei ◽  
...  

The ecological structure of Posidonia oceanica (L.) Delile meadows was evaluated on the northern coast of Lazio, Italy (central Tyrrhenian, Mediterranean sea). This is an infra-littoral zone with a wide range of anthropogenic activities and high geo-morphological variability, which reflects heterogeneity in shoot density, leaf morphology and biomass in fragmented patches. Genetic variability in populations corresponds to the formation of 3 sub-clusters, in the diverse impacted zones (north, centre and south), being correlated to the geographical distance between sites. AMOVA estimated a high genetic variation showing 43.05% individual differences within populations with a marked differentiation among the populations (56.9%) indicated by Fst value (0.57). These results revealed the role of the genetic structure of seagrasses for determining selectivity of fragmented habitat, in response to natural drivers. They showed that site-specific self-recruitment is related to biodiversity capacity and to the geo-morphological characteristic of the coast.


Author(s):  
Rajesh Bahadur Thapa ◽  
Manabu Watanabe ◽  
Masanobu Shimada ◽  
Takeshi Motohka

2020 ◽  
Vol 43 (8) ◽  
pp. 2076-2091 ◽  
Author(s):  
A. B. Novak ◽  
M. C. Pelletier ◽  
P. Colarusso ◽  
J. Simpson ◽  
M. N. Gutierrez ◽  
...  

Abstract Increasing the protection of coastal vegetated ecosystems has been suggested as one strategy to compensate for increasing carbon dioxide (CO2) in the atmosphere as the capacity of these habitats to sequester and store carbon exceeds that of terrestrial habitats. Seagrasses are a group of foundation species that grow in shallow coastal and estuarine systems and have an exceptional ability to sequester and store large quantities of carbon in biomass and, particularly, in sediments. However, carbon stocks (Corg stocks) and carbon accumulation rates (Corg accumulation) in seagrass meadows are highly variable both spatially and temporally, making it difficult to extrapolate this strategy to areas where information is lacking. In this study, Corg stocks and Corg accumulation were determined at 11 eelgrass meadows across New England, representing a range of eutrophication and exposure conditions. In addition, the environmental factors and structural characteristics of meadows related to variation in Corg stocks were identified. The objectives were accomplished by assessing stable isotopes of δ13C and δ15N as well as %C and %N in plant tissues and sediments, measuring grain size and 210Pb of sediment cores, and through assessing site exposure. Variability in Corg stocks in seagrass meadows is well predicted using commonly measured environmental variables such as grain size distribution. This study allows incorporation of data and insights for the northwest Atlantic, where few studies on carbon sequestration by seagrasses have been conducted.


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