Relative importance of available energy, environmental heterogeneity, and seed availability for seedling emergence on a limestone pavement

Botany ◽  
2010 ◽  
Vol 88 (12) ◽  
pp. 1045-1056 ◽  
Author(s):  
J. T. Lundholm
Keyword(s):  
Species Richness ◽  
Environmental Heterogeneity ◽  
Environmental Control ◽  
Environmental Gradients ◽  
Spatial Scales ◽  
Elevation Gradient ◽  
Experimental Studies ◽  
Relative Increase ◽  
Available Energy ◽  
Richness Patterns

Environmental heterogeneity at fine spatial scales is expected to be especially important in determining community patterns at seed germination and establishment stages. I compared seedling and adult species richness patterns in relation to environmental gradients by adding seeds from 39 species across an elevation gradient, unimodally related to species richness on a limestone pavement. Environmental variables linked to habitat fertility (“available energy”), within-plot spatial or temporal variability (“environmental heterogeneity”), and spatial coordinates were evaluated as contributors to richness patterns using variance partitioning. Variables related to available energy explained most of the variance in species richness for adults and seedlings in sown plots; pure spatial variation, shared variation between energy and heterogeneity variables, and other shared fractions explained more of the variance in seedling richness in unsown plots. Seedling density and richness increased with sowing, but the relative increase differed along the elevation gradient; relative increase in richness was greatest at the lowest and highest elevations. Limited seed dispersal from parent plants may result in seedlings colonizing less favorable microsites in unsown plots, whereas sowing resulted in greater explained variance owing to environmental factors, and lower variance attributable to space alone, indicating that appropriate species are more able to reach suitable microsites. While many experimental studies have revealed associations between microsite characteristics and species-specific recruitment responses, seed limitations in natural communities can contribute to the spatial structure of seedling communities and mask environmental control of seedling species richness.

scholarly journals The pitfalls of biodiversity proxies: Differences in richness patterns of birds, trees and understudied diversity across Amazonia

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Camila D. Ritter ◽  
Søren Faurby ◽  
Dominic J. Bennett ◽  
Luciano N. Naka ◽  
Hans ter Steege ◽  
...  
Keyword(s):  
Species Richness ◽  
Large Scale ◽  
Spatial Scales ◽  
Local Environment ◽  
Life Forms ◽  
Taxonomic Group ◽  
Diversity Gradients ◽  
Richness Patterns ◽  
Taxonomic Groups ◽  
Micro Organisms

AbstractMost knowledge on biodiversity derives from the study of charismatic macro-organisms, such as birds and trees. However, the diversity of micro-organisms constitutes the majority of all life forms on Earth. Here, we ask if the patterns of richness inferred for macro-organisms are similar for micro-organisms. For this, we barcoded samples of soil, litter and insects from four localities on a west-to-east transect across Amazonia. We quantified richness as Operational Taxonomic Units (OTUs) in those samples using three molecular markers. We then compared OTU richness with species richness of two relatively well-studied organism groups in Amazonia: trees and birds. We find that OTU richness shows a declining west-to-east diversity gradient that is in agreement with the species richness patterns documented here and previously for birds and trees. These results suggest that most taxonomic groups respond to the same overall diversity gradients at large spatial scales. However, our results show a different pattern of richness in relation to habitat types, suggesting that the idiosyncrasies of each taxonomic group and peculiarities of the local environment frequently override large-scale diversity gradients. Our findings caution against using the diversity distribution of one taxonomic group as an indication of patterns of richness across all groups.

The Vegetation: Hierarchical Species-Environment Relationships

2001 ◽  
Author(s):  
Marilyn D. Walker ◽  
Donald A. Walker
Keyword(s):  
Spatial Patterns ◽  
Environmental Gradients ◽  
Spatial Scales ◽  
Elevation Gradient ◽  
Community Research ◽  
Physical Factors ◽  
Community Patterns ◽  
Niwot Ridge ◽  
Critical Boundary ◽  
The Individual

The vegetation of Niwot Ridge has a rich history of study, beginning with phytosociological studies directly on the Ridge and in the surrounding mountains and incorporating more experimental and dynamic approaches in later years. This chapter provides an overview of the spatial patterns of Niwot Ridge plants and plant communities relative to the primary controlling environmental gradients at scales from the individual to the landscape. The spatial patterns of vegetation at all scales are dominated by physical forces, particularly the interaction of wind, snow, and topography. The controls of biotic factors on the distribution and abundance of plant species on Niwot Ridge have received considerably less attention than have physical factors, but recent studies have revealed the importance of competition and certain mutualisms in structuring community composition. Community research on Niwot Ridge has been organized around a hierarchy of spatial scales, from the plot to the region. Plot-based studies have focused on physiological and ecological dynamics of specific species and communities, and more spatially extensive studies have provided a hierarchical framework for the plot studies. In this chapter, we first present an overview of the broader patterns in the vegetation, followed by descriptions of the communities, and then the specifics of physical and biotic controls on species and plant growth that drive the community patterns. The landscape-scale patterns in the Niwot vegetation are driven by a complex elevation gradient, which is a combination of temperature and snow regime, with wind modifying and interacting with temperature and snow at all points along the gradient (chapter 2). Certainly the most critical boundary in the system is the upper tree limit, which defines the alpine system and which lies roughly between 3400 and 3600 m elevation on Niwot Ridge. Billings (1988) provided a climatic-floristic-physiographic review of major North American alpine systems that helps to place Niwot Ridge into a larger perspective. Climatically, Niwot is intermediate between the dry Sierras, which have greater precipitation but almost none of it falling during the summer, and the wetter northern Appalachians (Mt. Washington), which have fairly even annual precipitation and no drought.

scholarly journals High species richness turnover of vascular epiphytes is associated with water availability along the elevation gradient of Volcán Maderas, Nicaragua

2021 ◽  
Author(s):  
Hazel Berrios ◽  
Indiana Coronado ◽  
Travis Marsico
Keyword(s):  
Species Richness ◽  
Cloud Forest ◽  
Elevation Gradient ◽  
Species Abundance ◽  
Dry Forest ◽  
Ecological Groups ◽  
Humid Forest ◽  
Tropical Mountains ◽  
Vascular Epiphytes ◽  
Richness Patterns

Research that has been conducted documenting species richness patterns on tropical mountains has resulted in conflicting observations: monotonic declines with increasing elevation, monotonic increase with increasing elevation, and a mid-elevation ‘bulge.’ Currently, it is unclear if these differences are due to environmental differences associated with the various study areas, the taxonomic groups or ecological groups (e.g., growth form) sampled, or the scale of the study area along an elevation gradient. Because of the difficulty in sampling and identifying canopy-dwelling plants, the number of inventories quantifying tropical epiphytes is relatively limited and recent. In this study, we provide a detailed qualitative and quantitative assessment of the vascular epiphyte flora and its spatial distribution on Volcán Maderas, Isla de Ometepe, Nicaragua, including weather and environmental measurements along the entire elevation gradient of the volcano. We sampled epiphytes in five distinct forest types associated with increasing elevation as follows: dry forest, humid forest, wet forest, cloud forest, and elfin forest Five weather stations were placed along the elevation gradient for us to relate observed patterns to environmental conditions. A hump-shaped species richness pattern was detected for all vascular epiphytes at approximately 1000 m in elevation (cloud forest), yet species abundance increased with increasing elevation. In total we obtained 206 unique species identifications of vascular epiphytes belonging to 26 families and 73 genera. The most species-rich family was the Orchidaceae with 55 species for the entire elevation gradient, followed by Bromeliaceae (29 species), Araceae (23), Polypodiaceae (25), Dryopteridaceae (16), and Piperaceae (11), with all other families respresented by fewer than 10 species each. We found that richness patterns differ phylogenetically within epiphytes, possibly due to different adaptive strategies, and species for the most part appear to be narrowly distributed within specific habitat zones along the elevation gradient.

scholarly journals Changes in the acoustic structure and composition along a tropical elevational gradient

2017 ◽  
Vol 1 (1) ◽  
pp. 1-1 ◽  
Author(s):  
Marconi Campos-Cerqueira ◽  
T. Mitchell Aide
Keyword(s):  
Environmental Gradients ◽  
Spatial Scales ◽  
Elevation Gradient ◽  
Elevational Gradient ◽  
Conservation Strategies ◽  
Elevational Gradients ◽  
Acoustic Structure ◽  
Lack Of Information ◽  
Luquillo Mountains ◽  
Acoustic Community

Elevational gradients influence the distribution and composition of animal species and can provide useful information for the development of conservation strategies in the context of climate change. Despite an increase in studies of species diversity along elevational gradients, there is still a lack of information about community responses to environmental gradients, in part because of the logistical limitations of sampling multiple taxa simultaneously. One solution is to use passive acoustic monitoring (PAM) to acquire and analyze information from different animal taxa simultaneously along an entire elevational gradient. To improve our understanding of how environmental gradients influence patterns of animal communities and to test the relationship between soundscapes and animal composition we investigated how variation in bird and anuran composition affect the acoustic structure and composition of the soundscapes along an elevation gradient. We used PAM deploying portable acoustic recorders along three elevational transects in the Luquillo Mountains (LM), Puerto Rico. We found that elevation plays a major role in structuring the acoustic community and that the soundscape composition reflected the same patterns of anuran and bird distribution and composition along the elevational gradient. This study shows how different animal taxa respond to environmental gradients and provide strong evidence for the use of soundscapes as a tool to describe and compare species distribution and composition across large spatial scales.

Riparian bryophyte vegetation in the Cascade mountain range, Northwest U.S.A.: patterns at different spatial scales

1997 ◽  
Vol 75 (5) ◽  
pp. 744-761 ◽  
Author(s):  
Bengt Gunnar Jonsson
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Environmental Gradients ◽  
Woody Debris ◽  
Spatial Scales ◽  
Regional Distribution ◽  
Mountain Range ◽  
Old Growth ◽  
Old Growth Forest ◽  
Stream Size

Riparian forests are productive and species rich ecosystems where the vegetation is structured by sharp environmental gradients. The study describes community patterns of bryophytes in stream-side forests, relates these patterns to major environmental gradients, and compares within-site factors with site level variables. Samples were collected from 360 plots 2 × 4 m in size distributed among 42 sites in old-growth Pseudotsuga–Tsuga forests. The sites ranged from 420 to 1250 m asl and stream size from 1st to 5th order streams. There were significant changes in species richness and composition along several environmental gradients. Richness within sites varied among different geomorphic surfaces with the highest number of species on areas periodically flooded. Richness was also higher in plots with high abundance of woody debris. No site level factors influenced richness at the sample plot level, while the highest species number at the site level was for large streams. The main gradients in the species composition within sites were changes with increasing distance from the stream and amount of woody debris. Both elevation and stream size significantly influenced species composition. The complex set of factors that influenced species richness and composition implies that management of riparian vegetation must be based on both coarse scale considerations such as regional distribution of different stream types and fine scale factors such as spatial availability of different substrate types. Key words: old-growth forest; CCA analysis; fluvial disturbance; bryophytes; elevation effects; coarse woody debris.

scholarly journals Contrasting Gymnosperm Diversity Across an Elevation Gradient in the Ecoregion of China: The Role of Temperature and Productivity

2021 ◽  
Vol 9 ◽  
Author(s):  
Bikram Pandey ◽  
Kaiwen Pan ◽  
Mohammed A. Dakhil ◽  
Ziyan Liao ◽  
Arbindra Timilsina ◽  
...  
Keyword(s):  
Species Richness ◽  
Elevation Gradient ◽  
Aridity Index ◽  
Climatic Variables ◽  
Equation Modeling ◽  
Precipitation Pattern ◽  
Elevation Gradients ◽  
Precipitation Seasonality ◽  
Richness Pattern ◽  
Richness Patterns

The species richness–climate relationship is a significant concept in determining the richness patterns and predicting the cause of its distribution. The distribution range of species and climatic variables along elevation have been used in evaluating the elevational diversity gradients (EDG). However, the species richness of gymnosperms along elevation and its driving factors in large geographic areas are still unknown. Here, we aimed at evaluating the EDG of gymnosperms in the ecoregions of China. We divided the geographical region of China into 34 ecoregions and determine the richness pattern of gymnosperm taxa along elevation gradients. We demonstrated the richness patterns of the 237-gymnosperm (219 threatened, 112 endemic, 189 trees, and 48 shrubs) taxa, roughly distributed between 0 and 5,300 m (above sea level) in China. As possible determinants of richness patterns, annual mean temperature (TEMP), annual precipitation (PPT), potential evapotranspiration (PET), net primary productivity (SNPP), aridity index (AI), temperature seasonality (TS), and precipitation seasonality (PS) are the major predictor variables driving the EDG in plants. We used the species interpolation method to determine the species richness at each elevation band. To evaluate the richness pattern of gymnosperms in an ecoregion, generalized additive modeling and structural equation modeling were performed. The ecoregions in the southern part of China are rich in gymnosperm species, where three distinct richness patterns—(i) hump-shaped, (ii) monotonic increase, and (iii) monotonic decline—were noticed in China. All climatic variables have a significant effect on the richness pattern of gymnosperms; however, TEMP, SNPP, TS, and PS explained the highest deviance in diversity-rich ecoregions of China. Our results suggests that the highest number of gymnosperms species was found in the southwestern and Taiwan regions of China distributed at the 1,600- and 2,800-m elevation bands. These regions could be under severe stress in the near future due to expected changes in precipitation pattern and increase of temperature due to climate change. Thus, our study provided evidence of the species–climate relationship that can support the understanding of future conservation planning of gymnosperms.

scholarly journals Environmental heterogeneity predicts global species richness patterns better than area

2021 ◽  
Author(s):  
Kristy Udy ◽  
Matthias Fritsch ◽  
Katrin M. Meyer ◽  
Ingo Grass ◽  
Sebastian Hanß ◽  
...  
Keyword(s):  
Species Richness ◽  
Environmental Heterogeneity ◽  
Richness Patterns ◽  
Better Than

scholarly journals Area and environmental heterogeneity could shape the hump-shaped pattern of species richness along elevation gradient

2019 ◽  
Author(s):  
WAIGWA ANTONY NJOGU ◽  
Anne Christine Ochola ◽  
Shengwei Wang ◽  
Gituru Robert Wahiti ◽  
Yadong Zhou ◽  
...  
Keyword(s):  
Species Richness ◽  
Environmental Heterogeneity ◽  
Elevation Gradient ◽  
Strong Positive Correlation ◽  
Climate Factors ◽  
Soil Factors ◽  
Elevation Gradients ◽  
Richness Pattern ◽  
The Impact ◽  
Shaped Pattern

Abstract Background Numerous studies have been conducted on species richness patterns along elevation gradients in temperate, tropical and sub-tropical mountains. However, few studies have been done to evaluate the combined effect of area and environmental heterogeneity (abiotic and biotic) on species richness. Numerous ecological studies have also failed to quantify environmental heterogeneity which we have done in this research. In this research, we studied the impact of area on environmental heterogeneity on species richness by considering the climate factors, annual mean temperature (AMT), annual mean precipitation (AMP), annual total solar radiation (ATSR), and Soil factors, soil organic carbon (SOC), Soil total nitrogen (STN), Soil extractable phosphorous (SEP), and Soil extractable potassium (SEK).Results Our analysis showed that species richness had a skewed hump-shaped pattern, with the highest species richness being at mid-elevation. The results also showed that climate factors had a strong positive correlation with species richness in relation to area as compared to soil factors. We also found that soil factors could be used to explain the species richness when combined rather than being interpreted individually. This study has showed that area could have profound effect on environmental heterogeneity therefore shaping species richness pattern along the elevation gradient in Mount Kenya.Conclusion The hump shaped species richness pattern can be due to the Ecophysiological constraints for example, low temperatures as elevation increases. The high species richness at the mid-elevation is because this zone has a large land area and also acts as transition zone between the extremes of the upper elevation range and lower elevation and species from either side can coexist since the environmental conditions are on the lower and higher limits for the existence of these plant species.

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