scholarly journals Diversity indices based on angle count sampling and their interrelationships when used in forest inventories

2008 ◽  
Vol 81 (5) ◽  
pp. 587-597 ◽  
Author(s):  
H. Sterba
Keyword(s):  
Diversity Indices ◽  
Forest Inventories ◽  
Angle Count Sampling

Correcting the nondetection bias of angle count sampling

2013 ◽  
Vol 43 (4) ◽  
pp. 344-354 ◽  
Author(s):  
Tim Ritter ◽  
Arne Nothdurft ◽  
Joachim Saborowski
Keyword(s):  
Forest Inventory ◽  
Distance Sampling ◽  
Sampling Technique ◽  
Approximately Unbiased ◽  
Forest Inventories ◽  
Novel Approach ◽  
Inclusion Probabilities ◽  
Detection Probabilities ◽  
Efficient Sampling ◽  
Angle Count Sampling

The well-known angle count sampling (ACS) has proved to be an efficient sampling technique and has been applied in forest inventories for many decades. However, ACS assumes total visibility of objects; any violation of this assumption leads to a nondetection bias. We present a novel approach, in which the theory of distance sampling is adapted to traditional ACS to correct for the nondetection bias. Two new estimators were developed based on expanding design-based inclusion probabilities by model-based estimates of the detection probabilities. The new estimators were evaluated in a simulation study as well as in a real forest inventory. It is shown that the nondetection bias of the traditional estimator is up to −52.5%, whereas the new estimators are approximately unbiased.

Angle count sampling reliability as ground truth for area-based LiDAR applications in forest inventories

2015 ◽  
Vol 45 (4) ◽  
pp. 506-514 ◽  
Author(s):  
Gianfranco Scrinzi ◽  
Fabrizio Clementel ◽  
Antonio Floris
Keyword(s):  
Ground Truth ◽  
Visual Assessment ◽  
Volume Estimation ◽  
Tree Canopy ◽  
Volume Data ◽  
Ground Truth Data ◽  
Forest Inventories ◽  
Fixed Area ◽  
Fixed Radius ◽  
Angle Count Sampling

LiDAR-based techniques to estimate forest variables at the stand level require accurate calibration through ground truth data. One purpose of this study was to verify whether angle count samples can be used as suitable ground truth to calibrate LiDAR-based models for timber volume estimation. Volume data were acquired on the ground for 79 plots in the Latemar forest (province of Bolzano, Italian Alps). A simple linear regression model, using the sum of all of the tree canopy heights in the plot as the explanatory variable, was adopted. As angle count samples have no fixed area, three different methods to approximate their size were compared. The angle count sample area can be properly approximated by visual assessment of the tree size classes and by callipering the largest tree in the plot. The results show that angle count sampling can be an efficient solution to calibrate LiDAR-based models: they produced fair estimates at the plot level (relative root mean square error (RMSE), 26.6%) that were better than fixed-radius plot estimates with full callipering (RMSE, 29.7%). Estimate uncertainty at increasingly large forest stand areas was also calculated by means of a simulation procedure. It showed that low uncertainty (standard error of estimate = approximately 2%) could be reached at a forest compartment level (19 ha on average).

FLORISTIC DIVERSITY AND STRUCTURAL CHARACTERIZATION OF THE FOREST OF CHETTABA (ALGERIA)

2021 ◽  
Author(s):  
Zerrouki Alia ◽  
Kara Karima ◽  
Redjaimia Lilia ◽  
Rached-Kanouni Malika
Keyword(s):  
Management Strategies ◽  
Basal Area ◽  
Diversity Indices ◽  
Floristic Diversity ◽  
Stand Growth ◽  
Sustainable Resource Management ◽  
Forest Inventories ◽  
Dense Forest ◽  
North Algeria

"The structure of various stands, defined as the diversity of trees in the stands, can be an indication of overall biodiversity and habitat suitability, be useful in predicting stand growth and provide stand details for forest inventories. In an effort to find sustainable resource management strategies, a study was conducted on the structural and ecological characteristics of stands in Chettaba forest (Algeria). In this study, six diversity indices were used to characterize the horizontal and spatial distribution of individuals in multi-species stands, using four plots, located in the Chettaba forest (East-North Algeria). The results obtained allowed us to note that P2 and P3 present similar average densities (600 feet/ha), the plots P1 and P4 present low average densities (250 feet/ha and 350 feet/ha). The average DBH values vary from 25.65 cm for the P2 stand to 30.61 cm for the P1 stand. The average basal area varied between 33.73 m²/ha (P3) and 18.92 m²/ha (P1). The Shannon and Weaver index reached its maximum in plot 4 with 8 species. The study allowed us to evaluate the floristic diversity of the forest. Moreover, it indicated the need for its integral protection for its dynamics towards a dense forest vegetation."

Thysanoptera diversity associated with Mexican lemon (Citrus aurantifolia Christm.)

2020 ◽  
Vol 13 (9) ◽  
Author(s):  
Francisco Javier Avendaño-Gutiérrez ◽  
Salvador Aguirre Paleo ◽  
Alejandro Morales Hernández ◽  
Venecia Quesadas-Béjar
Keyword(s):  
Biosphere Reserve ◽  
Simple Random Sampling ◽  
Diversity Indices ◽  
Diaphorina Citri ◽  
Program Calculation ◽  
Homogeneous Relation ◽  
Candidatus Liberibacter ◽  
Scirtothrips Citri ◽  
Species Richness And Abundance ◽  
First Time

Objective: To calculate the monthly relative abundance of Thysanoptera species, according to the Margalef, Simpson and Shannon-Wiener diversity indices. Design / Methodology / Approach: The work was carried out in three geographic units with conventional management, during January-December, 2019 in the Reserva de la Biosfera Zicuirán-Infiernillo (Biosphere Reserve), Michoacán, Mexico. In each unit, 10 trees were selected through simple random sampling. Thrips counts were performed on ten shoots per tree every 15 d, for a total of 7200 shoots in the three geographic units. Thysanoptera individuals were placed in entomological jars. The variables were: number of thrips collected per shoot in sampled tree and geographic unit (orchard). To estimate the specific richness and structure of species, the program "calculation of diversity indices DIVERS" was used. Results: In the three geographical units studied, the recorded presence of Thysanoptera accounted for 12 to 17 species. For Nueva Italia 12 recorded species, two were permanent (16.66%), five abundant (41.66%), one scarce (8.3%) and four rare (33.33%). In Zicuirán, three species were permanent (17.64%), six abundant (35.29%), two scarce (11.76%) and six rare (35.29%). In Los Hoyos, four species were permanent (26.66%), four abundant (26.66%) and seven rare (46.66%). The abundance of species was represented by the genus Frankliniella and the species Scolothrips sexmaculatus and Scirtothrips citri. The highest species richness and abundance was found from January to May. In October and November, the value of the calculated indices was zero, which shows less richness and abundance of individuals. The best species uniformity was recorded during January and December, which meant a more stable and homogeneous relation. Study limitations/Implications. Pest resurgence, presence of Candidatus Liberibacter spp. and its vector Diaphorina citri. Findings / Conclusions: in Nueva Italia, 12 species were taxonomically determined; in Los Hoyos 15, and in Zicuirán 17 species, which are reported for the first time in the state of Michoacán, Mexico. At the geographic unit "Los Hoyos" diversity was higher, uniform and stable.

Climate resilience through natural regeneration in degraded natural forests of south-eastern hilly region of Bangladesh

2019 ◽  
Vol 48 (3) ◽  
pp. 417-425
Author(s):  
Md Khayrul Alam Bhuiyan ◽  
Md Akhter Hossain ◽  
Abdul Kadir Ibne Kamal ◽  
Mohammed Kamal Hossain ◽  
Mohammed Jashimuddin ◽  
...  
Keyword(s):  
Tree Species ◽  
Natural Regeneration ◽  
Diversity Indices ◽  
Acacia Auriculiformis ◽  
Quantitative Structure ◽  
Natural Forests ◽  
Climate Resilience ◽  
Hilly Region ◽  
Major Cluster ◽  
Ecological Dominance

A study was conducted by using 5m × 5m sized 179 quadrates following multistage random sampling method for comparative regenerating tree species, quantitative structure, diversity, similarity and climate resilience in the degraded natural forests and plantations of Cox's Bazar North and South Forest Divisions. A total of 70 regenerating tree species were recorded representing maximum (47 species) from degraded natural forests followed by 43 species from 0.5 year 39 species from 1.5 year and 29 species from 2.5 year old plantations. Quantitative structure relating to ecological dominance indicated dominance of Acacia auriculiformis, Grewia nervosa and Lithocarpus elegans seedlings in the plantations whereas seedlings of Aporosa wallichii, Suregada multiflora and Grewia nervosa in degraded natural forests. The degraded natural forests possess higher natural regeneration potential as showed by different diversity indices. The dominance-based cluster analysis showed 2 major cluster of species under one of which multiple sub-clusters of species exists. Poor plant diversity and presence of regenerating exotic species in the plantations indicated poor climate resilience of forest ecosystem in terms of natural regeneration.

Tree Diversity Conservation Initiatives in Sacred Groves of Kathmandu Valley, Nepal

2020 ◽  
Vol 19 (1) ◽  
pp. 60-68
Author(s):  
Laxmi Joshi Shrestha ◽  
Mohan Devkota ◽  
Bhuvan Keshar Sharma
Keyword(s):  
Tree Species ◽  
Management System ◽  
Survey Methods ◽  
Belief Systems ◽  
Decisive Role ◽  
Diversity Indices ◽  
Kathmandu Valley ◽  
Sacred Grove ◽  
Sacred Groves ◽  
The Government

 The study was conducted in two sacred groves of Kathmandu Valley, Pashupati Sacred Grove, and Bajrabarahi Sacred Grove, aiming to analyze the diversity of tree species and their role in conserving biodiversity. Parallel transects with concentric circular plot survey methods were applied for data collection. During the study, 23 tree species belonging to 22 genera and 15 families were recorded in Pashupati sacred grove, whereas only 19 tree species belonging to 16 genera and 13 families were recorded from Bajrabarahi Sacred Grove. The Shannon-Weiner diversity indices were higher (H=1.91) in Pashupati Sacred Grove compared to Bajrabarahi Sacred Grove, with 1.80 Shanon-Weiner Indices. Three types of forest were recorded from Pashupati Sacred Grove, namely the Schima-Pyrus forest, Myrsine-Persea forest, and Quercus-Myrsine forest, and only one Neolitsiacuipala forest from Bajrabarahi Sacred Grove. The sacred grove is one of the pioneers and community-based management regimes of the forest resource management system. It plays a decisive role in biodiversity conservation as it associated with many taboos and belief systems, thus providing a better opportunity for conservation compared to that of the government management system.

Aquatic and semi aquatic Hemiptera community of Sonebeel, the largest wetland of Assam, northeastern India

2018 ◽  
Vol 10 (13) ◽  
pp. 12792-12799
Author(s):  
Anupama Saha ◽  
Susmita Gupta
Keyword(s):  
Species Richness ◽  
Pest Control ◽  
Relative Abundance ◽  
Species Distribution ◽  
Diversity Indices ◽  
Environmental Data ◽  
Northeastern India ◽  
Ecological Roles

Aquatic and semiaquatic Hemiptera bugs play significant ecological roles, and they are important indicators and pest control agents.  Little information is currently available concerning its populations in southern Assam.  This study assessed hemipterans in four sites of Sonebeel, the largest wetland in Assam (3458.12 ha at full storage level), situated in Karimganj District.  The major inflow and outflow of the wetland are the rivers Singla and Kachua, respectively (the Kachua drains into the Kushiyara River).  Samples were trapped with pond nets and were seasonally recorded.  This study recorded a total of 28 species of aquatic and semiaquatic hemipterans belonging to 20 genera under nine families.  Population, geographical and environmental data (e.g., rainfall) were used to assess the relative abundance of species, species richness and different diversity indices, and species distribution. 

scholarly journals Harmonising, improving and using social and recreational data in National Forest Inventories across Europe

2020 ◽  
Vol 77 (3) ◽  
Author(s):  
Mark A. Atkinson ◽  
David M. Edwards ◽  
Frank Søndergaard Jensen ◽  
Alexander P. N. van der Jagt ◽  
Ben R. Ditchburn ◽  
...  
Keyword(s):  
National Level ◽  
European Countries ◽  
Transport Infrastructure ◽  
National Forest ◽  
Qualitative Response ◽  
Forest Inventories ◽  
Recreational Services ◽  
National Forest Inventories ◽  
Funded Project ◽  
General Transport

Abstract Key message National Forest Inventories (NFIs) hold promise for monitoring and valuing of non-productive forest functions, including social and recreational services. European countries use a range of methods to collect social and recreational information within their NFI methodologies. Data collected frequently included general and recreation-specific infrastructure, but innovative approaches are also used to monitor recreational use and social abuse. Context Social and recreational indicators are increasingly valued in efforts to measure the non-productive value of forests in Europe. National Forest Inventories (NFIs) can be used to estimate recreational and social usage of forest land at a national level and relate this use to other biophysical, spatial and topographical features. Nonetheless, there is little information concerning the extent. Aims The study aims to identify the coverage of social and recreational data present in European NFIs including the types of data recorded as part of the NFI methodologies across European countries. It also aims to examine contrasting methods used to record social and recreational data and present recommendations for ways forward for countries to integrate these into NFI practice. Methods A pan-European questionnaire was designed and distributed to 35 counties as part of the EU-funded project Distributed, Integrated and Harmonised Forest Information for Bioeconomy Outlooks (DIABOLO). The questionnaire probed countries on all social and recreational data that was included within NFIs. Qualitative response data was analysed and recoded to measure the extent of social and recreational data recoded in European NFIs both as a function of the number of variable categories per country and the number of countries recording particular variables. Results Thirty-one countries reported at least one social or recreational variable over 12 categories of data. The most frequently recorded variables included ownership, general transport infrastructure and recreation-specific infrastructure. Countries collecting data over many different categories included Switzerland, Great Britain, Czech Republic, Luxemburg and Denmark. Conclusion The study proposes a specific set of indicators, based upon countries with well-developed social and recreational data in their NFIs, which could be used by other countries, and report on the extent to which these are currently collected across Europe. It discusses results and makes a series of recommendations concerning priorities for the inclusion of social and recreational data in European NFIs.

scholarly journals Microbiota identified from preserved Anopheles

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Bianca E Silva ◽  
Zvifadzo Matsena Zingoni ◽  
Lizette L. Koekemoer ◽  
Yael L. Dahan-Moss
Keyword(s):  
Microbial Diversity ◽  
Vector Competence ◽  
Mosquito Species ◽  
Anopheles Funestus ◽  
Cost Effective ◽  
Diversity Indices ◽  
Malaria Vectors ◽  
Microbial Composition ◽  
Culture Independent ◽  
Culture Dependent

Abstract Background Mosquito species from the Anopheles gambiae complex and the Anopheles funestus group are dominant African malaria vectors. Mosquito microbiota play vital roles in physiology and vector competence. Recent research has focused on investigating the mosquito microbiota, especially in wild populations. Wild mosquitoes are preserved and transported to a laboratory for analyses. Thus far, microbial characterization post-preservation has been investigated in only Aedes vexans and Culex pipiens. Investigating the efficacy of cost-effective preservatives has also been limited to AllProtect reagent, ethanol and nucleic acid preservation buffer. This study characterized the microbiota of African Anopheles vectors: Anopheles arabiensis (member of the An. gambiae complex) and An. funestus (member of the An. funestus group), preserved on silica desiccant and RNAlater® solution. Methods Microbial composition and diversity were characterized using culture-dependent (midgut dissections, culturomics, MALDI-TOF MS) and culture-independent techniques (abdominal dissections, DNA extraction, next-generation sequencing) from laboratory (colonized) and field-collected mosquitoes. Colonized mosquitoes were either fresh (non-preserved) or preserved for 4 and 12 weeks on silica or in RNAlater®. Microbiota were also characterized from field-collected An. arabiensis preserved on silica for 8, 12 and 16 weeks. Results Elizabethkingia anophelis and Serratia oryzae were common between both vector species, while Enterobacter cloacae and Staphylococcus epidermidis were specific to females and males, respectively. Microbial diversity was not influenced by sex, condition (fresh or preserved), preservative, or preservation time-period; however, the type of bacterial identification technique affected all microbial diversity indices. Conclusions This study broadly characterized the microbiota of An. arabiensis and An. funestus. Silica- and RNAlater®-preservation were appropriate when paired with culture-dependent and culture-independent techniques, respectively. These results broaden the selection of cost-effective methods available for handling vector samples for downstream microbial analyses.

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