Testing dominance-diversity hypotheses using data from abandoned plantations and pastures in Puerto Rico and Ecuador

2010 ◽  
Vol 26 (2) ◽  
pp. 247-250 ◽  
Author(s):  
Randall W. Myster

Ecosystems have long been categorized by their function and structure (Odum 1953) and dominance and diversity are among the most common structural parameters measured in plant communities. The dominance of a plant species over another has been defined by having (1) more individual plants in a given sampling plot, (2) more collective biomass, or (3) greater cover (i.e. leaf area), but implicit in all definitions is a better ability to capture resources, grow and compete. Alternatively, diversity is a community-wide parameter encompassing both the raw number of species and the distribution of individual plants among them. Combining dominance and diversity together gives curves that show the distribution of abundances within a community (Whittaker 1965, Wilson 1991) and explore how these two aspects of structure relate to each other, change over time, and compare between communities separated in time or space. These curves are also effective in displaying contrasting patterns of species richness, highlighting differences in evenness among assemblages, and comparing species abundance patterns across communities (Magurran 2004). Indeed combining the dominance of particular species and the relative importance of that species within a community can suggest a ranking in competitive success and niche differentiation.

Author(s):  
M. I. Dzhalalova ◽  
A. B. Biarslanov ◽  
D. B. Asgerova

The state of plant communities in areas located in the Tersko-Sulak lowland was studied by assessing phytocenotic indicators: the structure of vegetation cover, projective cover, species diversity, species abundance and elevated production, as well as automated decoding methods. There are almost no virgin soils and natural phytocenoses here; all of them have been transformed into agrocenoses (irrigated arable lands and hayfields, rice-trees and pastures). The long-term impact on pasture ecosystems of natural and anthropogenic factors leads to significant changes in the indigenous communities of this region. Phytocenoses are formed mainly by dry-steppe types of cereals with the participation of feather grass, forbs and ephemera, a semi-desert haloxerophytic shrub - Taurida wormwood. At the base of the grass stand is common coastal wormwood and Taurida wormwood - species resistant to anthropogenic influences. Anthropogenic impacts have led to a decrease in the number of species of feed-rich grain crops and a decrease in the overall productivity of pastures. Plant communities in all areas are littered with ruderal species. The seasonal dynamics of the land cover of the sites was estimated by the methods of automatic decoding of satellite images of the Landsat8 OLI series satellite for 2015, dated by the periods: spring - May 20, summer - July 23, autumn - October 20. Satellite imagery data obtained by Landsat satellite with a resolution in the multispectral image of 30 m per pixel, and in the panchromatic image - 10 m per pixel, which correspond to the requirements for satellite imagery to assess the dynamics of soil and vegetation cover. Lower resolution data, for example, NDVI MODIS, does not provide a reliable reflection of the state of soil and vegetation cover under arid conditions. In this regard, remote sensing data obtained from the Internet resource https://earthexplorer.usgs.gov/ was used.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Alexia Stokes ◽  
Guillermo Angeles ◽  
Fabien Anthelme ◽  
Eduardo Aranda-Delgado ◽  
Isabelle Barois ◽  
...  

Abstract Objectives Altitude integrates changes in environmental conditions that determine shifts in vegetation, including temperature, precipitation, solar radiation and edaphogenetic processes. In turn, vegetation alters soil biophysical properties through litter input, root growth, microbial and macrofaunal interactions. The belowground traits of plant communities modify soil processes in different ways, but it is not known how root traits influence soil biota at the community level. We collected data to investigate how elevation affects belowground community traits and soil microbial and faunal communities. This dataset comprises data from a temperate climate in France and a twin study was performed in a tropical zone in Mexico. Data description The paper describes soil physical and chemical properties, climatic variables, plant community composition and species abundance, plant community traits, soil microbial functional diversity and macrofaunal abundance and diversity. Data are provided for six elevations (1400–2400 m) ranging from montane forest to alpine prairie. We focused on soil biophysical properties beneath three dominant plant species that structure local vegetation. These data are useful for understanding how shifts in vegetation communities affect belowground processes, such as water infiltration, soil aggregation and carbon storage. Data will also help researchers understand how plant communities adjust to a changing climate/environment.


Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 552
Author(s):  
Janez Kermavnar ◽  
Lado Kutnar ◽  
Aleksander Marinšek

Forest herb-layer vegetation responds sensitively to environmental conditions. This paper compares drivers of both taxonomic, i.e., species richness, cover and evenness, and functional herb-layer diversity, i.e., the diversity of clonal, bud bank and leaf-height-seed plant traits. We investigated the dependence of herb-layer diversity on ecological determinants related to soil properties, climatic parameters, forest stand characteristics, and topographic and abiotic and biotic factors associated with forest floor structure. The study was conducted in different forest types in Slovenia, using vegetation and environmental data from 50 monitoring plots (400 m2 each) belonging to the ICP Forests Level I and II network. The main objective was to first identify significant ecological predictors and then quantify their relative importance. Species richness was strongly determined by forest stand characteristics, such as richness of the shrub layer, tree layer shade-casting ability as a proxy for light availability and tree species composition. It showed a clear positive relation to soil pH. Variation in herb-layer cover was also best explained by forest stand characteristics and, to a lesser extent, by structural factors such as moss cover. Species evenness was associated with tree species composition, shrub layer cover and soil pH. Various ecological determinants were decisive for the diversity of below-ground traits, i.e., clonal and bud bank traits. For these two trait groups we observed a substantial climatic signal that was completely absent for taxonomy-based measures of diversity. In contrast, above-ground leaf-height-seed (LHS) traits were driven exclusively by soil reaction and nitrogen availability. In synthesis, local stand characteristics and soil properties acted as the main controlling factors for both species and trait diversity in herb-layer communities across Slovenia, confirming many previous studies. Our findings suggest that the taxonomic and functional facets of herb-layer vegetation are mainly influenced by a similar set of ecological determinants. However, their relative importance varies among individual taxonomy- and functional trait-based diversity measures. Integrating multi-faceted approaches can provide complementary information on patterns of herb-layer diversity in European forest plant communities.


Ecography ◽  
1995 ◽  
Vol 18 (3) ◽  
pp. 310-317 ◽  
Author(s):  
Asa Eriksson ◽  
Ove Eriksson ◽  
Hans Berglund

Author(s):  
Mark Maltby

Concentrating mainly on the zooarchaeological data, this chapter reviews the evidence for the exploitation of animals in Roman Britain. The review focuses initially on domestic mammals and their exploitation, with particular attention being paid to the species that contributed the most to the diet—cattle, pig, and sheep. This discussion is followed by a shorter summary of the evidence for the exploitation of other mammals, birds, and fish. The relative importance of the different species for their meat and other commodities is outlined, and reasons for variations in species abundance, mortality patterns, butchery methods, and the stature of domestic stock are discussed. Chronological, regional, settlement, and cultural factors all need to be taken into account when considering the complexities of human–animal relationships in Roman Britain.


2020 ◽  
Author(s):  
Shinichi Tatsumi ◽  
Joachim Strengbom ◽  
Mihails Čugunovs ◽  
Jari Kouki

ABSTRACTChanges in species diversity often result from species losses and gains. The dynamic nature of beta diversity (i.e., spatial variation in species composition) that derives from such temporal species turnover, however, has been largely overlooked. Here, we disentangled extinction and colonization components of beta diversity by using the sets of species that went locally extinct and that newly colonized the given sites. We applied this concept of extinction and colonization beta diversity to plant communities that have been repeatedly measured in experimentally disturbed forests. We first found no difference in beta diversity across disturbance gradients when it was analyzed for communities at a single point in time. From this result, we might conclude that disturbance caused no impact on how species assemble across space. However, when we analyzed the extinction and colonization beta diversity, both measures were found to be significantly lower in disturbed sites compared to undisturbed sites. These results indicate that disturbance removed similar subsets of species across space, making communities differentiate, but at the same time induced spatially uniform colonization of new species, causing communities to homogenize. Consequently, the effects of these two processes canceled each other out. The relative importance of extinction and colonization components per se also changed temporally after disturbance. Analyses using extinction and colonization beta diversity allowed us to detect nonrandom dis- and re-assembly dynamics in plant communities. Our results suggest that common practices of analyzing beta diversity at one point in time can mask significant variation driven by disturbance. Acknowledging the extinction–colonization dynamics behind beta diversity is essential for understanding the spatiotemporal organization of biodiversity.


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