scholarly journals Role of the Dominant Species on the Distributions of Neighbor Species in a Subtropical Forest

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 352
Author(s):  
Shiguang Wei ◽  
Lin Li ◽  
Juyu Lian ◽  
Scott E. Nielsen ◽  
Zhigao Wang ◽  
...  
Keyword(s):  
Community Assembly ◽  
Dominant Species ◽  
Scale Effects ◽  
Southern China ◽  
Spatial Scales ◽  
Null Model ◽  
Subtropical Forest ◽  
Successional Stage ◽  
Species Groups

Understanding the role of dominant species in structuring the distribution of neighbor species is an important part of understanding community assembly, a central goal of ecology. Phylogenetic information helps resolve the multitude of processes driving community assembly and the importance of evolution in the assembly process. In this study, we classified species in a 20-ha subtropical forest in southern China into groups with different degrees of phylogenetic relatedness to the dominant species Castanopsis chinensis. Species surrounding individuals of C. chinensis were sampled in an equal area annulus at six spatial scales, counting the percent of relatives and comparing this to permutation tests of a null model and variance among species groups. The results demonstrated that dominant species affected their relatives depending on community successional stage. Theory would predict that competitive exclusion and density-dependence mechanisms should lead to neighbors that are more distant in phylogeny from C. chinensis. However, in mature forests distant relatives were subjected to competitive repulsion by C. chinensis, while environment filtering led to fewer distant species, regardless of scale. A variety of biological and non-biological factors appear to result in a U-shaped quantitative distribution determined by the dominant species C. chinensis. Scale effects also influenced the dominant species. As a dominant species, C. chinensis played an important role in structuring the species distributions and coexistence of neighbor species in a subtropical forest.

scholarly journals Increasing inundation frequencies enhance the stochastic process and network complexity of soil archaeal community in coastal wetlands

2021 ◽  
Author(s):  
Gui-Feng Gao ◽  
Dan Peng ◽  
Di Wu ◽  
Yihui Zhang ◽  
Haiyan Chu
Keyword(s):  
Stochastic Processes ◽  
Community Assembly ◽  
Coastal Wetlands ◽  
Southern China ◽  
Archaeal Community ◽  
Special Focus ◽  
Inundation Frequency ◽  
Occurrence Patterns ◽  
Archaeal Communities

Coastal wetlands are experiencing frequent flooding because of global climate changes, such as the rising sea level. Despite the key role of archaea in soil biogeochemical cycles, the assembly processes and co-occurrence patterns of archaeal communities in coastal wetlands in response to increasing inundation frequencies remain elusive. Herein, we established an in situ mesocosm with an inundation frequency gradient to investigate the response of soil archaeal community toward increasing inundation frequencies in monocultures of Spartina alterniflora (SA) and a mangrove species, Kandelia obovata (KO). Both neutral community model and null model analyses suggested that stochastic processes are dominant in governing the archaeal community assembly, and that the stochastic processes are enhanced with increasing inundation frequencies. Increasing inundation frequencies significantly increased the community niche width. Moreover, archaeal community in SA soil displayed lower niche overlap and higher stochasticity than in KO soil. Co-occurrence network analysis revealed that the network complexity increases with increase in the inundation frequencies. Soil water content is the most decisive factor influencing the archaeal communities. Overall, we found that increasing inundation frequencies enhance the stochastic processes and network complexity of the soil archaeal community in coastal wetlands. This study could enhance our understanding on the response of soil archaeal communities in coastal wetlands toward global change. Importance Coastal wetlands, subjected to regular disturbances by periodic tidal, are highly productive and important in the regulation of climate change. However, the assembly mechanisms and co-occurrence patterns of soil archaeal communities in coastal areas remain poorly known, especially for their responses to increasing inundation frequencies. In this study, we aim at unravelling these uncertainties by studying typical estuarine ecosystems in southern China. We show that increasing inundation frequencies enhance the stochastic processes and network complexity of the soil archaeal community. This study offers a new path for an improved understanding of archaeal community assembly and species coexistence in coastal environments, with a special focus on the role of inundation frequency.

scholarly journals A general framework for quantitatively assessing ecological stochasticity

2019 ◽  
Vol 116 (34) ◽  
pp. 16892-16898 ◽  
Author(s):  
Daliang Ning ◽  
Ye Deng ◽  
James M. Tiedje ◽  
Jizhong Zhou
Keyword(s):  
Organic Carbon ◽  
Vegetable Oil ◽  
Community Assembly ◽  
Spatial Scales ◽  
Null Model ◽  
Environmental Noise ◽  
Mathematical Framework ◽  
Oil Injection ◽  
Very High ◽  
Null Expectation

Understanding the community assembly mechanisms controlling biodiversity patterns is a central issue in ecology. Although it is generally accepted that both deterministic and stochastic processes play important roles in community assembly, quantifying their relative importance is challenging. Here we propose a general mathematical framework to quantify ecological stochasticity under different situations in which deterministic factors drive the communities more similar or dissimilar than null expectation. An index, normalized stochasticity ratio (NST), was developed with 50% as the boundary point between more deterministic (<50%) and more stochastic (>50%) assembly. NST was tested with simulated communities by considering abiotic filtering, competition, environmental noise, and spatial scales. All tested approaches showed limited performance at large spatial scales or under very high environmental noise. However, in all of the other simulated scenarios, NST showed high accuracy (0.90 to 1.00) and precision (0.91 to 0.99), with averages of 0.37 higher accuracy (0.1 to 0.7) and 0.33 higher precision (0.0 to 1.8) than previous approaches. NST was also applied to estimate stochasticity in the succession of a groundwater microbial community in response to organic carbon (vegetable oil) injection. Our results showed that community assembly was shifted from more deterministic (NST = 21%) to more stochastic (NST = 70%) right after organic carbon input. As the vegetable oil was consumed, the community gradually returned to be more deterministic (NST = 27%). In addition, our results demonstrated that null model algorithms and community similarity metrics had strong effects on quantifying ecological stochasticity.

scholarly journals Soil microbes drive phylogenetic diversity-productivity relationships in a subtropical forest

2019 ◽  
Vol 5 (10) ◽  
pp. eaax5088 ◽  
Author(s):  
Minxia Liang ◽  
Xubing Liu ◽  
Ingrid M. Parker ◽  
David Johnson ◽  
Yi Zheng ◽  
...  
Keyword(s):  
Phylogenetic Diversity ◽  
Spatial Scales ◽  
Pathogenic Fungi ◽  
Subtropical Forest ◽  
Negative Effects ◽  
Plant Soil ◽  
Extensive Field ◽  
Adult Trees ◽  
The Relationship

The relationship between plant diversity and productivity and the mechanisms underpinning that relationship remain poorly resolved in species-rich forests. We combined extensive field observations and experimental manipulations in a subtropical forest to test how species richness (SR) and phylogenetic diversity (PD) interact with putative root-associated pathogens and how these interactions mediate diversity-productivity relationships. We show that (i) both SR and PD were positively correlated with biomass for both adult trees and seedlings across multiple spatial scales, but productivity was best predicted by PD; (ii) significant positive relationships between PD and productivity were observed in nonsterile soil only; and (iii) root fungal diversity was positively correlated with plant PD and SR, while the relative abundance of putative pathogens was negatively related to plant PD. Our findings highlight the key role of soil pathogenic fungi in tree diversity-productivity relationships and suggest that increasing PD may counteract negative effects of plant-soil feedback.

scholarly journals Distribution Pattern of Trait-Based Community Assembly for Cyclobalanopsis Glauca in the Guilin Karst Mountainous Areas, China

2020 ◽  
Vol 13 ◽  
pp. 194008292098027
Author(s):  
Shichu Liang ◽  
Hongling Lin ◽  
Han Bao ◽  
Yipeng Yao ◽  
Yong Jiang ◽  
...  
Keyword(s):  
Community Assembly ◽  
Dominant Species ◽  
Woody Species ◽  
Shared Environment ◽  
Mountainous Areas ◽  
Successional Stage ◽  
High Resource ◽  
Species Trait ◽  
Succession Stage ◽  
Cyclobalanopsis Glauca

Cyclobalanopsis glauca is one of the most dominant species in the late succession stage of plant communities in the Guilin karst mountainous areas of China. In order to explore its role in community assembly and adaptation strategies, we quantified three continuous traits (LA, SLA and WD) for 52 woody species and documented community composition for 20 plots across different habitat conditions. We performed a trait-gradient analysis to partition species trait values between alpha and beta components within and between communities. Alpha trait components consistently varied more widely than beta components, which suggests that much of the trait variation between species was associated with different functional strategies within a shared environment. The different correlation structures for alpha and beta components reflects community assembly processes at different scales. The alpha components were largely uncorrelated with the exception of SLA and WD, while the beta components showed significant correlations along the environmental gradient. There is a significant positive correlation between LA and SLA and significant negative correlations between both LA and WD as well as between SLA and WD. These results demonstrate that slow-growing species with high resource-use efficiency gradually became the dominant species in the late successional stage for Cyclobalanopsis glauca forest and co-occurring species in the same community employ different trait assemblies.

The abundance and inter-specific relations of common ant species (Hymenoptera: Formicidae) on cocoa farms in western Nigeria

1978 ◽  
Vol 68 (1) ◽  
pp. 105-121 ◽  
Author(s):  
Brian Taylor ◽  
S. F. Adedoyin
Keyword(s):  
Dominant Species ◽  
Suitable Habitat ◽  
Intensive Study ◽  
Oecophylla Longinoda ◽  
Cocoa Farm ◽  
Wide Scale ◽  
Species Groups ◽  
Components Analysis ◽  
Associated Species

AbstractFollowing a demonstration of the role of ants in the dissemination of Phytophthora pod rot and an intensive study of the ant mosaic on cocoa at the Cocoa Research Institute of Nigeria, there was a need for a wide-scale assessment of the relative importance of different species of ant on cocoa farms in the major growing area of western Nigeria. Between 19 January and 6 February 1976, 50 trees were examined on each of 76 cocoa farms and all ant species visible from the ground were recorded. Sixteen species, or species-groups, of ants occurred on more than 1% of the trees, and their geographical distribution, habitat requirements and inter-specific relations were examined. The last of these were elucidated using principal components analysis, and the results are compared with earlier work on the ant mosiac. Any one cocoa farm only rarely provided a suitable habitat for more than one or two of the dominant species, and a diagram summarising the habitats is given. The potential usefulness of ant population manipulation is thought to be restricted in Nigeria by the undesirable effects of co-dominant and associated species found with the dominant species, Oecophylla longinoda (Latr.) and Tetramorium aculeatum (Mayr), which are regarded as beneficial in Ghana. The most important of the undesirable co-dominants is Pheidole megacephala (F.).

scholarly journals Community assembly and metaphylogeography of soil biodiversity: insights from haplotype-level community DNA metabarcoding within an oceanic island

2022 ◽  
Author(s):  
Carmelo Andujar ◽  
Paula Arribas ◽  
Heriberto López ◽  
Yurena Arjona ◽  
Antonio Pérez-Delgado ◽  
...  
Keyword(s):  
Community Assembly ◽  
Sequence Data ◽  
Spatial Scales ◽  
Oceanic Island ◽  
Soil Mesofauna ◽  
Soil Biodiversity ◽  
Dna Sequence Data ◽  
Dna Metabarcoding ◽  
Patterns And Processes

Most of our understanding of island diversity comes from the study of aboveground systems, while the patterns and processes of diversification and community assembly for belowground biotas remain poorly understood. Here we take advantage of a relatively young and dynamic oceanic island to advance our understanding of eco-evolutionary processes driving community assembly within soil mesofauna. Using whole organism community DNA (wocDNA) metabarcoding and the recently developed metaMATE pipeline, we have generated spatially explicit and reliable haplotype-level DNA sequence data for soil mesofaunal assemblages sampled across the four main habitats within the island of Tenerife. Community ecological and metaphylogeographic analyses have been performed at multiple levels of genetic similarity, from haplotypes to species and supraspecific groupings. Broadly consistent patterns of local-scale species richness across different insular habitats have been found, whereas local insular richness is lower than in continental settings. Our results reveal an important role for niche conservatism as a driver of insular community assembly of soil mesofauna, with only limited evidence for habitat shifts promoting diversification. Furthermore, support is found for a fundamental role of habitat in the assembly of soil mesofauna, where habitat specialism is mainly due to colonisation and the establishment of preadapted species. Hierarchical patterns of distance decay at the community level and metaphylogeographical analyses support a pattern of geographic structuring over limited spatial scales, from the level of haplotypes through to species and lineages, as expected for taxa with strong dispersal limitations. Our results demonstrate the potential for wocDNA metabarcoding to advance our understanding of biodiversity.

POLÍTICAS DE ESCALA E A CONFORMAÇÃO DE ESTRATÉGIAS-REDE DAS AÇÕES COLETIVAS NO ESPAÇO SISALEIRO DA BAHIA

GEOgraphia ◽  
2018 ◽  
Vol 19 (41) ◽  
pp. 39
Author(s):  
Agripino Souza Coelho Neto
Keyword(s):  
Political Action ◽  
Spatial Scales ◽  
Spatial Behavior ◽  
Collective Actions ◽  
Collective Behaviors ◽  
Rural Workers ◽  
Scale Levels ◽  
Scale Network ◽  
Comme Point

Resumo: O presente texto pretende analisar o papel das ações coletivas (associações, cooperativas e sindicatos de agricultores) no acionamento e na ativação das escalas geográficas para o desenvolvimento de suas atividades. O estudo foi realizado no Espaço Sisaleiro da Bahia (Brasil), onde um conjunto significativo de associações e cooperativas de agricultores e sindicatos de trabalhadores rurais tem se organizado em torno das escalas espaciais para viabilizar sua ação político-institucional e econômico-produtiva. A ação desses coletivos organizados em rede tem permitido a conformação e o fortalecimento de novas escalas de ação política, como no caso da criação do conselho territorial para viabilização da implantação de políticas de governo. Cooperativas, associações e sindicatos se apoiam nas escalas para compor organizações em diferentes níveis escalares (escala local, escala regional, escala do estado federado e escala nacional), buscando fortalecer seus propósitos e ampliar seu poder de barganha e influência. Analisando o comportamento espacial dessas variadas modalidades de ações coletivas, é possível considerar que elas desenvolvem políticas de escala, ou seja, a escala passa a significar muito mais que uma categoria de análise, mas se torna uma categoria da prática social e política. Nesse sentido, parte-se do pressuposto de que os grupos humanos produzem e tornam efetivas suas próprias escalas visando a alcançar suas metas e organizar seus comportamentos coletivos. Palavras-chave: Escala. Rede. Cooperativismo. Associativismo. Sindicalismo. Espaço Sisaleiro da Bahia. SCALE POLICIES AND THE DEVELOPMENT OF NETWORK STRATEGIES OF COLLECTIVE ACTIONS IN THE SISAL REGION OF BAHIA (BRAZIL)Abstract: This paper aims to analyze the role of collective initiatives of associations, cooperatives and farmers’ unions in the mobilization and activation of geographical scales for the development of their activities. The study was conducted in the Sisal Region of Bahia (Brazil), where a significant number of farmers associations and cooperatives and rural workers’ unions have been organizing their actions around spatial scales to enable their political-institutional and economic-productive influence. The gathering and action of these organized groups in a network have allowed the establishment and strengthening of new scales of political action, as seem in the case of the creation of a territorial council to facilitate the implementation of government policies. Cooperatives, associations, and unions rely on scales to form organizations at different scale levels (local, regional, federal and national scales), seeking to strengthen their performance and increase their bargaining power and influence. After analyzing the spatial behavior of these various forms of collective actions, it’s reasonable to say that they develop scale policies, which means the scale becomes more than a category of analysis, but also a category of social and political practice. In this sense, it’s assumed that human groups produce and utilize the scales in order to reach their goals and organize their own collective behaviors. Keywords: Scale. Network. Cooperativism. Associativism. Syndicalism. Sisal Region of Bahia. POLITIQUES D’ÉCHELLE ET FORMATION DES STRATÉGIES-RÉSEAU DES ACTIONS COLLECTIVES DANS LA RÉGION DU SISAL DE L’ÉTAT DE BAHIA Resumé: Cet article analyse le rôle des actions collectives (associations, coopératives et syndicats d’agriculteurs) dans la prise en compte et l’utilisation des échelles géographiques pour le développement de leurs activités. L’étude a été menée dans la région du sisal à Bahia (Brésil), où un ensemble important d’associations et de coopératives d’agriculteurs et de syndicats de travailleurs ruraux se sont organisés autour d’échelles spatiales pour que puisse être mise en place leur action politique et institutionnelle, économique et productive. L’action de ces groupements organisés en réseaux a permis la conformation et le renforcement de nouvelles échelles d’action politique, comme lors de la création du conseil territorial, pour permettre la mise en œuvre des politiques gouvernementales. Les coopératives, les associations et les syndicats prennent les échelles comme point de départ pour former des organisations à différents niveaux scalaires (échelle locale, échelle régionale, échelle fédérée et échelle nationale), dans le but de renforcer leurs objectifs et d’accroître leur pouvoir de négociation et d’influence. Si nous analysons le comportement spatial de ces diverses formes d’action collective il est possible de considérer qu’ils développent des politiques d’échelle, à savoir l’échelle vient signifier bien plus qu’une catégorie d’analyse, puisqu’elle devient une catégorie de la pratique sociale et politique. En ce sens, on suppose que les groupes humains produisent et rendent efficaces leurs propres échelles pour atteindre leurs objectifs et organiser leurs comportements collectifs. Mots-clés: Échelle. Réseau. Coopérativisme. Associations. Syndicalisme. Région du sisal de l’État de Bahia.

scholarly journals The effects of armed conflict on forest cover changes across temporal and spatial scales in the Colombian Amazon

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Oscar V. Bautista-Cespedes ◽  
Louise Willemen ◽  
Augusto Castro-Nunez ◽  
Thomas A. Groen
Keyword(s):  
Armed Conflict ◽  
Forest Cover ◽  
Spatial Scales ◽  
Armed Forces ◽  
Peace Negotiations ◽  
Post Conflict ◽  
Forest Cover Changes ◽  
The Government ◽  
Colombian Amazon

AbstractThe Amazon rainforest covers roughly 40% of Colombia’s territory and has important global ecological functions. For more than 50 years, an internal war in the country has shaped this region. Peace negotiations between the government and the Revolutionary Armed Forces of Colombia (FARC) initiated in 2012 resulted in a progressive de-escalation of violence and a complete ceasefire in 2016. This study explores the role of different deforestation drivers including armed conflict variables, in explaining deforestation for three periods between 2001 and 2015. Iterative regression analyses were carried out for two spatial extents: the entire Colombian Amazon and a subset area which was most affected by deforestation. The results show that conflict variables have positive relationships with deforestation; yet, they are not among the main variables explaining deforestation. Accessibility and biophysical variables explain more variation. Nevertheless, conflict variables show divergent influence on deforestation depending on the period and scale of analysis. Based on these results, we develop deforestation risk maps to inform the design of forest conservation efforts in the post-conflict period.

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