Alvar vegetation in Canada: a multivariate description at two scales

Alvars are areas with a distinctive dry grassland vegetation growing in thin soil over level limestone, and they are documented in Scandinavia, the eastern United States, and central Canada. Ordination and classification analysis techniques were used to describe alvar vegetation in Canada at two scales: within one alvar and among four alvar sites. Within one alvar, changes in species composition corresponded to changes in soil depth and biomass. There were two main vegetation types: (i) alvar meadows with complete vegetation cover and (ii) rock flats with incomplete vegetation cover over limestone rock. Among alvars, species composition was related primarily to geographic location. The southern site was distinct from the eastern and northern sites. Relationships between soil depth, plant biomass, and vegetation could also be detected. At within and among alvar scales, tall perennial graminoids dominated sites with deep soil while small annuals and stress-tolerant perennials dominated shallow soil sites. Average biomass levels were strongly positively correlated with soil depth across vegetation types. Average species richness was curvilinearly related to biomass. Our results describe Canadian alvar vegetation and illustrate important differences among alvar sites, showing that a number of these sites need protection to conserve alvar vegetation. Key words: grassland, drought, soil depth, species richness, biomass, conservation.

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Effects of biomass extraction on vegetation structure, diversity and composition of forests in Sariska Tiger Reserve, India

Environmental Conservation ◽

10.1017/s0376892905002316 ◽

2005 ◽

Vol 32 (3) ◽

pp. 248-259 ◽

Cited By ~ 64

Author(s):

RAMAN KUMAR ◽

GHAZALA SHAHABUDDIN

Keyword(s):

Species Richness ◽

Species Composition ◽

Vegetation Structure ◽

Riparian Forest ◽

Canopy Cover ◽

Basal Area ◽

Vegetation Types ◽

Tiger Reserve ◽

Scrub Forest ◽

Structure Diversity

Despite the fact that tropical dry forests are being exploited on a large scale for various forest products, there has been limited evaluation of the accompanying ecological impacts. In particular, there is no information on the effects of widespread biomass extraction such as grazing and firewood collection. A study was carried out in Sariska Tiger Reserve in northern India, to investigate the effects of biomass extraction on forest vegetation composition, diversity and structure. Biomass extraction caused significant changes in forest vegetation structure and species composition in the tree layer but the extent of these changes varied across the three major vegetation types found in the Reserve. Anogeissus-dominated slope forest showed significantly lower mean canopy cover, tree density, tree basal area and height of trees in disturbed sites in comparison to undisturbed sites. Riparian forest showed lower mean canopy cover, tree basal areas and number of recorded tree species in disturbed sites. Scrub forest had lower mean canopy cover, tree basal area and tree height. There were fewer tall trees but greater number of short trees in disturbed sites of all three vegetation types. Girths of trees similarly shifted towards lower values in riparian and scrub forest. In Anogeissus-dominated forest, disturbed and undisturbed sites did not differ in proportions of trees in various girth-classes. Tree species richness was substantially lower in disturbed sites of Anogeissus-dominated and riparian forest in comparison to undisturbed sites, but was not affected by disturbance in scrub forest. Understorey species richness was higher in disturbed sites of all three vegetation types but understorey changed structurally only in Anogeissus-dominated forest. Overall tree and understorey species composition was significantly different between disturbed and undisturbed sites of Anogeissus-dominated forest, but was unchanged in scrub and riparian forest. Observed changes in vegetation structure, diversity and composition of the different vegetation types due to biomass extraction have implications for biodiversity conservation in tropical dry forest ecosystems, and need to be addressed in future forest management planning.

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The predominant role of soil in determining species composition of fern communities in subtropical coastal forest ecosystems

Neotropical Biology and Conservation ◽

10.3897/neotropical.14.e49028 ◽

2019 ◽

Vol 14 (4) ◽

pp. 559-575

Author(s):

Amanda Angélica Carmes ◽

Michele de Sá Dechoum ◽

Pedro Fiaschi

Keyword(s):

Species Richness ◽

Species Composition ◽

Atlantic Forest ◽

Vegetation Structure ◽

Environmental Variables ◽

Abiotic Factors ◽

Canopy Openness ◽

Vegetation Types ◽

Edaphic Conditions ◽

Fern Species

Ferns are an important component in the understorey of tropical forests and their distribution is influenced by several biotic and abiotic factors. At a regional scale, soil characteristics and canopy openness play an important role in fern species composition and richness, as well as in the abundance of individuals. Our objective was to compare the influence of edaphic conditions and vegetation structure on the abundance and distribution of fern communities in Atlantic forest and restinga forest. Our hypotheses were that fern species richness and diversity are higher in Atlantic forest than in restinga due to limiting conditions in this habitat and the composition of fern species in Atlantic forest differs from restinga, especially due to differences in edaphic conditions. A principal coordinates analysis was applied to ordinate sampling units in relation to the environmental variables and a permutational multivariate analysis of variance was used to test that environmental variables did not differ between the two vegetation types. Species richness was compared using rarefaction curves. The influence of abiotic variables in species composition and abundance was verified using canonical correspondence analysis. No differences were observed in species richness, diversity or dominance between vegetation types, although abundance was higher in restinga. Fern communities respond to edaphic conditions and vegetation structure variations between vegetation types, the soil playing a major role. A greater variety of habitats resulting from differences in soil drainage in restinga facilitates the co-existence of species with different ecological tolerance, increasing local diversity and compensating for limiting conditions in restinga.

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Comparison of Drivers of Soil Microbial Communities Developed in Karst Ecosystems with Shallow and Deep Soil Depths

Agronomy ◽

10.3390/agronomy11010173 ◽

2021 ◽

Vol 11 (1) ◽

pp. 173

Author(s):

Huiling Guan ◽

Jiangwen Fan ◽

Haiyan Zhang ◽

Warwick Harris

Keyword(s):

Microbial Community ◽

Microbial Communities ◽

Soil Depth ◽

Phospholipid Fatty Acid ◽

Soil Microbial Communities ◽

Deep Soil ◽

Soil System ◽

Soil Microbial ◽

Total Soil ◽

Karst Ecosystems

Soil erosion is prevalent in karst areas, but few studies have compared the differences in the drivers for soil microbial communities among karst ecosystems with different soil depths, and most studies have focused on the local scale. To fill this research gap, we investigated the upper 20 cm soil layers of 10 shallow–soil depth (shallow–SDC, total soil depth less than 100 cm) and 11 deep–soil depth communities (deep–SDC, total soil depth more than 100 cm), covering a broad range of vegetation types, soils, and climates. The microbial community characteristics of both the shallow–SDC and deep–SDC soils were tested by phospholipid fatty acid (PLFAs) analysis, and the key drivers of the microbial communities were illustrated by forward selection and variance partitioning analysis. Our findings demonstrated that more abundant soil nutrients supported higher fungal PLFA in shallow–SDC than in deep–SDC (p < 0.05). Furthermore, stronger correlation between the microbial community and the plant–soil system was found in shallow–SDC: the pure plant effect explained the 43.2% of variance in microbial biomass and 57.8% of the variance in the ratio of Gram–positive bacteria to Gram–negative bacteria (G+/G−), and the ratio of fungi to total bacteria (F/B); the pure soil effect accounted for 68.6% variance in the microbial diversity. The ratio of microbial PLFA cyclopropyl to precursors (Cy/Pr) and the ratio of saturated PLFA to monounsaturated PLFA (S/M) as indicators of microbial stress were controlled by pH, but high pH was not conducive to microorganisms in this area. Meanwhile, Cy/Pr in all communities was >0.1, indicating that microorganisms were under environmental stress. Therefore, the further ecological restoration of degraded karst communities is needed to improve their microbial communities.

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Relationships between resource availability and elevation vary between metrics creating gradients of nutritional complexity

Oecologia ◽

10.1007/s00442-020-04824-4 ◽

2021 ◽

Vol 195 (1) ◽

pp. 213-223

Author(s):

Mark A. Lee ◽

Grace Burger ◽

Emma R. Green ◽

Pepijn W. Kooij

Keyword(s):

Species Richness ◽

Plant Species ◽

Resource Availability ◽

Plant Biomass ◽

Plant Species Richness ◽

Mineral Contents ◽

Nutritive Values ◽

Animal Community ◽

Nutritional Chemistry ◽

The Relationship

AbstractPlant and animal community composition changes at higher elevations on mountains. Plant and animal species richness generally declines with elevation, but the shape of the relationship differs between taxa. There are several proposed mechanisms, including the productivity hypotheses; that declines in available plant biomass confers fewer resources to consumers, thus supporting fewer species. We investigated resource availability as we ascended three aspects of Helvellyn mountain, UK, measuring several plant nutritive metrics, plant species richness and biomass. We observed a linear decline in plant species richness as we ascended the mountain but there was a unimodal relationship between plant biomass and elevation. Generally, the highest biomass values at mid-elevations were associated with the lowest nutritive values, except mineral contents which declined with elevation. Intra-specific and inter-specific increases in nutritive values nearer the top and bottom of the mountain indicated that physiological, phenological and compositional mechanisms may have played a role. The shape of the relationship between resource availability and elevation was different depending on the metric. Many consumers actively select or avoid plants based on their nutritive values and the abundances of consumer taxa vary in their relationships with elevation. Consideration of multiple nutritive metrics and of the nutritional requirements of the consumer may provide a greater understanding of changes to plant and animal communities at higher elevations. We propose a novel hypothesis for explaining elevational diversity gradients, which warrants further study; the ‘nutritional complexity hypothesis’, where consumer species coexist due to greater variation in the nutritional chemistry of plants.

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Disentangling the Ecological Determinants of Species and Functional Trait Diversity in Herb-Layer Plant Communities in European Temperate Forests

Forests ◽

10.3390/f12050552 ◽

2021 ◽

Vol 12 (5) ◽

pp. 552

Author(s):

Janez Kermavnar ◽

Lado Kutnar ◽

Aleksander Marinšek

Keyword(s):

Species Richness ◽

Species Composition ◽

Plant Communities ◽

Functional Trait ◽

Forest Stand ◽

Relative Importance ◽

Herb Layer ◽

Bud Bank ◽

Tree Species Composition ◽

Stand Characteristics

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.

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Vegetation Cover and Tumuli’s Shape as Affecting Factors of Microclimate and Biodeterioration Risk for the Conservation of Etruscan Tombs (Tarquinia, Italy)

Sustainability ◽

10.3390/su13063393 ◽

2021 ◽

Vol 13 (6) ◽

pp. 3393

Author(s):

Giulia Caneva ◽

Simone Langone ◽

Flavia Bartoli ◽

Adele Cecchini ◽

Carlo Meneghini

Keyword(s):

Vegetation Cover ◽

Cynodon Dactylon ◽

Soil Depth ◽

Late Summer ◽

Positive Influence ◽

Wild Plants ◽

Affecting Factors ◽

Ephemeral Plants ◽

Relevant Role ◽

Hot Season

The conservation of underground tombs is affected by several physical-chemical and biological factors, which could be reduced by insulating systems able to maintain the microclimatic stability also decreasing the biodeterioration risk. In Mediterranean areas, wild ephemeral plants, which reduce their cover during the hot season, seem unsuitable for reducing summer overheating. In this study, we wish to assess the influence of vegetation cover and of overlaying soil, after the establishment of an evergreen turf of a cultivar of Cynodon dactylon, on two tombs in the Etruscan Necropolis of Monterozzi, covered by linear-shaped tumuli. Therefore, we evaluated for 10 months the thermo-hygrometric values of these tombs, together with two tombs as controls. We also evaluated the different tumuli’s morphologies and the related received solar radiation. Results confirmed that late summer and early autumn as critical microclimatic periods for the risk factors of hypogeal paintings when peaks of superficial temperature occur. A positive influence of vegetation cover on maintaining constant humidity and internal temperatures was detected, but the mounds orientation, as well as soil depth, seems to have a relevant role. Considering the naturalistic features of the area and the related cultural ecosystem services, a careful selection of wild plants is suggested.

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Species richness and species composition of fungal communities associated with cellulose decomposition at different altitudes on the Tibetan Plateau

Journal of Plant Ecology ◽

10.1093/jpe/rtp028 ◽

2009 ◽

Vol 2 (4) ◽

pp. 217-224 ◽

Cited By ~ 5

Author(s):

D. Hirose ◽

T. Shirouzu ◽

M. Hirota ◽

T. Ohtsuka ◽

Y. Senga ◽

...

Keyword(s):

Species Richness ◽

Tibetan Plateau ◽

Species Composition ◽

Fungal Communities ◽

The Tibetan Plateau ◽

Cellulose Decomposition ◽

Different Altitudes

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A Spatial Index for Identifying Opportunity Zones for Woody Cellulosic Conversion Facilities

International Journal of Forestry Research ◽

10.1155/2012/106474 ◽

2012 ◽

Vol 2012 ◽

pp. 1-11 ◽

Cited By ~ 3

Author(s):

Xia Huang ◽

James H. Perdue ◽

Timothy M. Young

Keyword(s):

Spatial Data ◽

Family Income ◽

Market Competition ◽

Geographic Location ◽

Forest Growth ◽

Farm Income ◽

Eastern United States ◽

Landscape Index ◽

Ownership Type ◽

South Central

A challenge in the development of renewable energy is the ability to spatially assess the risk of feedstock supply to conversion facilities. Policy makers and investors need improved methods to identify the interactions associated with landscape features, socioeconomic conditions, and ownership patterns, and the influence these variables have on the geographic location of potential conversion facilities. This study estimated opportunity zones for woody cellulosic feedstocks based on landscape suitability and market competition for the resource. The study covered 13 Southern States which was a segment of a broader study that covered 33 Eastern United States which also included agricultural biomass. All spatial data were organized at the 5-digit zip code tabulation area (ZCTA). A landscape index was developed using factors such as forest land cover area, net forest growth, ownership type, population density, median family income, and farm income. A competition index was developed based on the annual growth-to-removal ratio and capacities of existing woody cellulosic conversion facilities. Combining the indices resulted in the identification of 592 ZCTAs that were considered highly desirable zones for woody cellulosic conversion facilities. These highly desirable zones were located in Central Mississippi, Northern Arkansas, South central Alabama, Southwest Georgia, Southeast Oklahoma, Southwest Kentucky, and Northwest Tennessee.

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