scholarly journals Relationship between ecological stoichiometry and community diversity of plant ecosystems in the upper reaches of the Tarim River, China

2018 ◽  
Author(s):  
Jingjing Zhao ◽  
Lu Gong ◽  
Xin Chen

AbstractAimAlthough it is commonly proposed that nutrient cycling can impact plant community diversity, this relationship has not been fully examined in arid and semi-arid zones. Here, we expand on the framework for evaluating the relationship between biodiversity and ecological stoichiometry by scaling up from the level of the community.LocationThe upper reaches of the Tarim River (Northwest China, 80°10’-84°36’E, 0°25’-41°10’N).MethodsWe used multivariate analysis of variance to compare the stoichiometric characteristics and species diversity indices of sampled plant communities. We also measured carbon (C), nitrogen (N), and phosphorous (P) content of plants. We then assessed correlations between community stoichiometry and species diversity through structural equation models (SEM) and redundancy analysis (RDA).ResultsWe found that the differences between stoichiometric characteristics and community diversity indices were highly significant. The Margalef index was strongly related to C and P content. The Simpson’s index and Shannon-Weaner index were most strongly correlated with C content. Pielou’s index was closely related to C and N contents, and the C:N and C:P ratios were important at driving ecological dominance.Main ConclusionsOur study highlights the importance of ecological stoichiometry in driving community assembly and diversity within a desert ecosystems in northwestern China. The relationship between eclogical stoichiometry in the desert plant community had an effect on species diversity, and it was a good indicator of plant community diversity.

2020 ◽  
Author(s):  
Xiyi Wang ◽  
Tingting Ma ◽  
Hongbo Ling ◽  
Shuzhen Peng

Abstract Background: The lower reaches of the Tarim River is an arid region of inland China. In this area, vegetation is sparse and the environment is fragile. Therefore, it is of great significance to study the structure and stability of the plant community and ecosystem in the lower reaches of the Tarim River. It is valuable to increase the understanding of ecological protection and restoration in arid areas. Methods: In this study, four sections, Yingsu, Karday, Alakan, and Yiganbjm, were selected as research sites, and 96 arbor and shrub quadrats and 288 herb quadrats were delimited in these sites. The ecological characteristics of all species in the quadrats were investigated. We selected the surveyed data from 2000, 2004, 2008, 2012, 2016, and 2019. Based on the data, we analyzed the variations in species composition. We also determined Shannon-Wiener indexes, Alatalo indexes, and ecological dominance to discuss the species diversity and uniformity of plant community. Plant community stability were also evaluated. Results: There were 17 species in 2000 and 31 species in 2019. The proportion of arbor and shrub species decreased, while the understory herbaceous species gradually increased; all of the species become balanced. The stability of the plant community gradually increased; however, it remained unstable. Conclusions: In general, water conveyance in an ecosystem plays a positive role in promoting the restoration of vegetation and ecological stability. This study provides a new method for the evaluation of ecological protection and restoration benefits in arid areas. Our findings can be a good reference for similar studies.


Author(s):  
Yang Wang ◽  
Jin Chen ◽  
Limin Zhang ◽  
Ling Feng ◽  
Lingbin Yan ◽  
...  

The relationships among species diversity, functional diversity, functional redundancy, and community stability are central to community and ecosystem ecology. This paper examines plant communities at different stages of vegetation restoration in the Guizhou karst plateau to study the relationship among functional diversity, functional redundancy, and stability of plant communities. The most important results include the following. (1) Species diversity (SD), functional redundancy (FR), and stability (STB) gradually increased with restoration, and there were significant differences among the different stages; functional diversity (FD) increased at first and then decreased, and reached the highest level at the tree irrigation stage. (2) Plant height (PLH) and specific leaf area (SLA) were functional traits that affected the diversity and stability of the plant community, and PLH was positively correlated with plant community diversity and stability, while SLA was negatively correlated with plant community diversity and stability. (3) During the community recovery, FD and FR interacted to maintain stability. In the early and late stages of recovery, the effect of functional redundancy on stability was greater than that of functional diversity, but it was the opposite in the middle stages. (4) The tree irrigation stage is the likely point at which the species diversity of plant communities in karst areas reached saturation, and the growth rate of functional redundancy after species diversity saturation was greater than that before saturation.


Botany ◽  
2008 ◽  
Vol 86 (12) ◽  
pp. 1416-1426 ◽  
Author(s):  
Amy C. Ganguli ◽  
David M. Engle ◽  
Paul M. Mayer ◽  
Eric C. Hellgren

Widespread encroachment of the fire-intolerant species Juniperus virginiana  L. into North American grasslands and savannahs where fire has largely been removed has prompted the need to identify mechanisms driving J. virginiana encroachment. We tested whether encroachment success of J. virginiana is related to plant species diversity and composition across three plant communities. We predicted J. virginiana encroachment success would (i) decrease with increasing diversity, and (ii) J. virginiana encroachment success would be unrelated to species composition. We simulated encroachment by planting J. virginiana seedlings in tallgrass prairie, old-field grassland, and upland oak forest. We used J. virginiana survival and growth as an index of encroachment success and evaluated success as a function of plant community traits (i.e., species richness, species diversity, and species composition). Our results indicated that J. virginiana encroachment success increased with increasing plant richness and diversity. Moreover, growth and survival of J. virginiana seedlings was associated with plant species composition only in the old-field grassland and upland oak forest. These results suggest that greater plant species richness and diversity provide little resistance to J. virginiana encroachment, and the results suggest resource availability and other biotic or abiotic factors are determinants of J. virginiana encroachment success.


2019 ◽  
Vol 39 (22) ◽  
Author(s):  
牛玉斌 NIU Yubin ◽  
余海龙 YU Hailong ◽  
王攀 WANG Pan ◽  
樊瑾 FAN Jin ◽  
王艳红 WANG Yanhong ◽  
...  

2021 ◽  
Vol 13 (13) ◽  
pp. 2467
Author(s):  
Sabelo Madonsela ◽  
Moses A. Cho ◽  
Abel Ramoelo ◽  
Onisimo Mutanga

The emergence of the spectral variation hypothesis (SVH) has gained widespread attention in the remote sensing community as a method for deriving biodiversity information from remotely sensed data. SVH states that spectral heterogeneity on remotely sensed imagery reflects environmental heterogeneity, which in turn is associated with high species diversity and, therefore, could be useful for characterizing landscape biodiversity. However, the effect of phenology has received relatively less attention despite being an important variable influencing plant species spectral responses. The study investigated (i) the effect of phenology on the relationship between spectral heterogeneity and plant species diversity and (ii) explored spectral angle mapper (SAM), the coefficient of variation (CV) and their interaction effect in estimating species diversity. Stratified random sampling was adopted to survey all tree species with a diameter at breast height of > 10 cm in 90 × 90 m plots distributed throughout the study site. Tree species diversity was quantified by the Shannon diversity index (H′), Simpson index of diversity (D2) and species richness (S). SAM and CV were employed on Landsat-8 data to compute spectral heterogeneity. The study applied linear regression models to investigate the relationship between spectral heterogeneity metrics and species diversity indices across four phenological stages. The results showed that the end of the growing season was the most ideal phenological stage for estimating species diversity, following the SVH concept. During this period, SAM and species diversity indices (S, H′, D2) had an r2 of 0.14, 0.24, and 0.20, respectively, while CV had an r2 of 0.22, 0.22, and 0.25, respectively. The interaction of SAM and CV improved the relationship between the spectral data and H′ and D2 (from r2 of 0.24 and 0.25 to r2 of 0.32 and 0.28, respectively) at the end of the growing season. The two spectral heterogeneity metrics showed differential sensitivity to components of plant diversity. SAM had a high relationship with H′ followed by D2 and then a lower relationship with S throughout the different phenological stages. Meanwhile, CV had a higher relationship with D2 than other plant diversity indices and its relationship with S and H′ remained similar. Although the coefficient of determination was comparatively low, the relationship between spectral heterogeneity metrics and species diversity indices was statistically significant (p < 0.05) and this supports the assertion that SVH could be implemented to characterize plant species diversity. Importantly, the application of SVH should consider (i) the choice of spectral heterogeneity metric in line with the purpose of the SVH application since these metrics relate to components of species diversity differently and (ii) vegetation phenology, which affects the relationship that spectral heterogeneity has with plant species diversity.


2014 ◽  
Author(s):  
Hansraj Gautam ◽  
G. G. Potdar ◽  
T.N.C. Vidya

AbstractQuestionsTo assess the feasibility of using visually-estimated cover in rapid assessment of herbivore food species abundance in the grass layer, we asked the following questions: 1) What is the relationship between total graminoid cover and biomass in forests, and does height improve the prediction of biomass from cover? 2) How does total cover relate to biomass in a grassland habitat? 3) How does elephant food species graminoid cover relate to individual species biomass? 4) How well does species diversity of forest understorey grass layer, calculated from cover data, mirror that calculated from biomass data?LocationNagarahole National Park, India.MethodsWe estimated the abundance of graminoids through visual estimation of cover and weighted harvested biomass in forest and grassland plots. In forests, two estimates of total graminoid abundance, total graminoid cover and sum of species covers, were used. In the grassland, only total graminoid abundance was measured. We examined the relationship between cover estimates and biomass, and the additional utility of height in predicting biomass, using multiple regressions and AIC-based model selection. We also assessed similarity in cover- and biomass-based Simpson’s and Shannon-Wiener diversity indices using regressions.ResultsGraminoid cover explained a large portion of variation in total graminoid biomass in forest and grassland habitats. The sum of species covers was better than total cover in estimating total graminoid biomass in the forest. The benefit of including height to estimate total biomass was moderate in forests but substantial in grassland. Cover estimates were good proxies of food species biomass, and the addition of height did not yield better models for most species. Species diversity indices calculated from cover largely matched those based on biomass.ConclusionsVisual estimation of species cover is a good alternative to biomass harvesting for rapid assessment of abundance of graminoids consumed by generalist herbivores, like elephants.


2021 ◽  
Author(s):  
Yuan Liu ◽  
Xuli Ren ◽  
Qixiao Zhang ◽  
Qiaoyu Li ◽  
Chunyan She ◽  
...  

Abstract Aims The mechanism by which species diversity drives productivity in different ecosystems is controversial, possibly due to the confounding effects of key environmental variables. Karst ecosystems are fragile and are at great risk of species loss. In these ecosystems, soil depth is a key driver of community diversity and productivity. However, the influence of soil depth on the relationship between species diversity and productivity in karst ecosystems remains unclear.Methods We established artificial karst herbaceous communities with different soil depths and species richness levels and determined how two biodiversity effects—complementarity effect (effect of positive interactions among species) and selection effect (effect due to dominance of productive species)—contributed to productivity.Results Soil depth, species diversity, and different species combinations were significant predictors of productivity. Species diversity significantly positively affected productivity at all three soil depths, with the effect size of species diversity being the greatest in medium-depth soil. Net diversity effects were greater than 0 in all multi-species communities, indicating that complementarity and selection effects both positively influenced productivity. However, complementarity effect had a greater contribution to productivity than selection effect in all multi-species communities. Furthermore, the contribution of complementarity effect increased with increasing soil depth, while that of selection effect decreased.Conclusions Soil depth influences the relationship between species diversity and productivity in karst herbaceous communities. Furthermore, complementarity effect is the major mechanism by which diversity increases community productivity, particularly in shallow soil. Therefore, environmental variables should be seriously considered when studying the relationship between species diversity and function in other ecosystems.


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