scholarly journals Differences in plant cover and species composition of semiarid grassland communities of central Mexico and its effects on net ecosystem exchange

2013 ◽  
Vol 10 (7) ◽  
pp. 4673-4690 ◽  
Author(s):  
J. Delgado-Balbuena ◽  
J. T. Arredondo ◽  
H. W. Loescher ◽  
E. Huber-Sannwald ◽  
G. Chavez-Aguilar ◽  
...  
Keyword(s):  
Land Use ◽  
Species Composition ◽  
Plant Communities ◽  
Plant Cover ◽  
Shrub Encroachment ◽  
Photon Flux ◽  
Large Variability ◽  
Semiarid Grassland ◽  
C Balance ◽  
C Cycle

Abstract. Changes in land use across the semiarid grasslands of northern Mexico have driven a decline of plant cover and alteration of plant species composition. A number of different plant communities have resulted from these changes. Their implications, however, on the carbon (C) cycle and regional carbon balance are still poorly understood. Here, we examined the effects of plant cover loss and changes in species composition on net ecosystem CO2 exchange (NEE) and their biotic and abiotic controls. NEE was measured in five representative plant community types within a semiarid grassland by temporarily enclosing the entire aboveground ecosystem using a chamber method (i.e., geodesic dome). Sites included an oat crop (crop), a moderately grazed grassland (moderate grazing), a 28 yr-old grazing exclosure (exclosure), an overgrazed site with low perennial grass cover (overgrazed), and an overgrazed site presenting shrub encroachment (shrub encroachment). For natural vegetation, rates of standardized daytime NEE for sites with a high plant cover (exclosure and moderate grazing) were similar (P > 0.05) as compared to sites with low plant cover (overgrazed and shrub encroachment). However, yearly total nighttime NEE (carbon loss) was more than double (P < 0.05) for sites with high plant cover compared to sites with low cover, resulting to slight C sinks for the low plant cover sites, and neutral or sources for the high plant cover sites as accounted by daytime and nighttime NEE annual balance. Differences in plant cover and its associated biomass defined the sensitivity to environmental controls. Thus, daytime NEE in low plant cover sites reached light compensation points at lower photosynthetic photon flux density than those from high plant cover sites. Differences in species composition did not influence NEE rates even though there were transient or permanent changes in C3 vs. C4 functional groups. Our results allowed the detection of the large variability and contribution of different plant communities to regional C balance in patchy landscapes. Identification of the role of landscape patches in the regional C balance as either sinks or sources may provide tools allowing land use management strategies that could favor C uptake in patchy landscapes.

scholarly journals Differences in plant cover and species composition of semiarid grassland communities of Central Mexico and its effects on net ecosystem exchange

2012 ◽  
Vol 9 (12) ◽  
pp. 17099-17137 ◽  
Author(s):  
J. Delgado-Balbuena ◽  
J. T. Arredondo ◽  
H. W. Loescher ◽  
E. Huber-Sannwald ◽  
G. Chavez-Aguilar ◽  
...  
Keyword(s):  
Species Composition ◽  
Plant Cover ◽  
Perennial Grass ◽  
Net Ecosystem Exchange ◽  
Co2 Exchange ◽  
Shrub Encroachment ◽  
Night Time ◽  
Semiarid Grassland ◽  
Environmental Controls ◽  
Abiotic Controls

Abstract. Changes in land use across the semiarid grasslands of Northern Mexico have driven a decline of plant cover and alteration of plant species composition. A number of different plant communities have resulted from these changes, however, their implications on the carbon cycle and regional carbon balance are still poorly understood. Here, we examined the effects of plant cover loss and changes in species composition on net ecosystem CO2 exchange (NEE) and their biotic and abiotic controls. Five typical plant community types were examined in the semiarid grassland by encasing the entire above-ground ecosystem using the geodesic dome method. Sites included an oat crop (crop), a moderately grazed grassland (moderate grazing), a 28 yr-old grazing exclosure (exclosure), an overgrazed site with low perennial grass cover (overgrazed), and an overgrazed site presenting shrub encroachment (shrub encroachment). For natural vegetation, rates of daytime NEE for sites with a high plant cover (exclosure and moderate grazing) were similar (P>0.05) as compared to sites with low plant cover (overgrazed and shrub encroachment). However, night time NEE (carbon loss) was more than double (P<0.05) for sites with high plant cover compared to sites with low cover, resulting into slight C sinks for the low plant cover sites and neutral or sources for the high plant cover sites on an annual basis. Differences in plant cover and its associated biomass defined the sensitivity to environmental controls. Thus, daytime NEE in low plant cover sites reached light compensation points at lower PPFD values than those from high plant cover sites. Differences in species composition did not influence NEE rates even though there were transient or permanent changes in C3 vs. C4 functional groups.

scholarly journals Vegetation changes in boreo–nemoral forest stands depending on soil factors and past land use during an 80 year period of no human impact

2016 ◽  
Vol 46 (3) ◽  
pp. 376-386 ◽  
Author(s):  
Ilze Kokarēviča ◽  
Guntis Brūmelis ◽  
Raimonds Kasparinskis ◽  
Arta Rolava ◽  
Oļģerts Nikodemus ◽  
...  
Keyword(s):  
Land Use ◽  
Species Composition ◽  
Plant Communities ◽  
Agricultural Land ◽  
Deciduous Forest ◽  
Tree Canopy ◽  
Temperate Deciduous Forest ◽  
Soil Factors ◽  
Nature Protection ◽  
Forest Zone

Information on the long-term changes in plant communities that occur without human interference is limited, due to insufficient studies where vegetation can be resurveyed. In 1912, a strict nature protection reserve, with non-intervention management, was established on Moricsala Island in Latvia, located in the boreo–nemoral forest zone. Prior to establishment of the nature reserve, part of the island area was used for agriculture. The island is now covered almost entirely by forest dominated by Quercus robur L. and Tilia cordata Mill. on sandy soils. Resurvey was conducted in 2011 in 17 plots in which tree layers and the understory vegetation had been described in 1930. The plots were classified into two groups based on tree species composition in 1930 to determine changes in species composition. Differences in understory and tree canopy composition between these groups persisted over the period between the studies, in relation to soil factors and past stand history. Considerable turnover of species occurred, with a decrease of species typical of open habitats and replacement by species typical of nemoral (temperate deciduous) forest plant communities. In the past, Q. robur had likely established in open habitats created by agricultural land use or past fire but is presently not regenerating in the understory.

scholarly journals Age and Land Use as Factors Differentiating Hydrochemistry and Plant Cover of Astatic Ponds in Post-Agricultural Landscape

2014 ◽  
Vol 21 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Monika Mętrak ◽  
Paweł Pawlikowski ◽  
Małgorzata Suska-Malawska
Keyword(s):  
Land Use ◽  
Species Composition ◽  
Agricultural Landscape ◽  
Plant Cover ◽  
Direct Influence ◽  
Catchment Scale ◽  
Influence Of Water ◽  
Species Composition Of Vegetation ◽  
Northeastern Poland ◽  
Agricultural Areas

Abstract Small, astatic ponds are important features of post-glacial landscape, which support heterogeneity and biodiversity of agricultural areas. In the presented research we explored differences in hydrochemistry and plant cover of 20 small ponds located in Northeastern Poland, characterized by diverse age and developed in differently managed areas. According to our research, though changes in water level are under direct influence of water balance in the catchment, to which belonged the ponds, their hydrochemistry seemed to be shaped by processes at the level lower than the catchment scale. Age of the ponds appeared to be an important factor influencing density and species composition of vegetation developed on the studied ponds.

scholarly journals Changes of plant cover of the raised peat-bog Baligówka under the influence of human activity

2016 ◽  
Vol 27 (4) ◽  
pp. 7-11
Author(s):  
Magdalena Malec ◽  
Sławomir Klatka ◽  
Marek Ryczek ◽  
Edyta Kruk
Keyword(s):  
Species Composition ◽  
Plant Communities ◽  
Groundwater Level ◽  
Plant Cover ◽  
Chemical Properties ◽  
Peat Bog ◽  
Physical And Chemical Properties ◽  
Peat Formation ◽  
Physical And Chemical ◽  
And Chemical Properties

Abstract The main purpose of the work was to determine the scope and degree of the influence of exploitation on changes of plant cover of the raised peat-bog Baligówka, located in the Orawsko- Nowotarska Valley. The analysis was carried out based on 47 phytosociological surveys using the Braun-Blanquet method. Results of investigations allow to state that excessive drying and fires that took place on the examined object caused wastage of many precious species of plants, especially from the Oxycocco- Sphagnetea class. Their place occupied species belonging to other classes, such as Nardo-Callunetea and Molinio-Arrhenatheretea. The basic cause of drying of the peat-bog and, in consequence, dying of peat formation species is intensified exploitation and connected with this drainage, carried out in the half of the 20th century. Unfortunately, local people up to now illegally have harvested the peat on the investigated object. Decrease in groundwater level leads to accelerated decay of peat, changes in physical and chemical properties of a substratum and, in consequence, changes in trophic values of habitat, what causes great changes in species composition of plant communities.

Biospheric Sustainability in a Changing World

2019 ◽  
pp. 197-218
Author(s):  
Emily W. B. Russell Southgate
Keyword(s):  
United States ◽  
Land Use ◽  
Land Use Change ◽  
Species Composition ◽  
Plant Communities ◽  
Critical Factor ◽  
Human Populations ◽  
Northeastern United States ◽  
The Holocene ◽  
Time Changes

This chapter discusses the concept of sustainability using as a specific example concerns about the sustainability of oak-dominated forests in the northeastern United States. The discussion from the first edition is updated with current research, leading to the conclusion that climate is the most critical factor in determining species ranges even in human-dominated landscapes, and that fluctuations during the Holocene have been reflected not only in altered species composition of forests, but also in human populations and thus land use. At the same time, changes wrought by people have influenced decadal dynamics, such as secondary successional patterns, and often all but eliminated species within some plant communities, by land use change. Merely comparing present to inferred processes in the past misses vital factors in change; inference must be supported by historical data. Worldwide, droughts inferred from multi-proxy data can be correlated with declines in human populations as well as with changed vegetation, regardless of the complexity of the civilizations and agricultural systems. Managing systems for sustainability, requires consideration of legacies left by past land use.

scholarly journals Plant community recovery from intense deer grazing depends on reduction of graminoids and the time after exclosure installation in a semi-natural grassland

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7833 ◽  
Author(s):  
Chiaki Otsu ◽  
Hayato Iijima ◽  
Takuo Nagaike
Keyword(s):  
Species Composition ◽  
Plant Community ◽  
Plant Communities ◽  
Sika Deer ◽  
Plant Cover ◽  
Dissimilarity Index ◽  
Large Herbivores ◽  
Community Recovery ◽  
One Year ◽  
Deer Grazing

Exclosures that exclude large herbivores are effective tools for the protection and restoration of grazed plant communities. However, previous studies have shown that the installation of an exclosure does not ensure plant community recovery. Our study aimed to determine the effects of the domination of unpalatable plants and the timing of exclosure installation on the plant community recovery process in montane grassland overgrazed by sika deer (Cervus nippon) in Japan. In this study we compared plant species composition and their cover with inside and outside exclosures installed at different times. Furthermore, we also compared them with those in 1981, when density of sika deer was very low. We used quadrats inside and outside fenced areas established in 2010 and 2011 to record both the cover and the height of species in each quadrat between 2011 and 2015. Plant cover, with the exception of graminoid species, increased in later years in all treatments. Non-metric multidimensional scaling (NMDS) plots showed significantly differentiated treatment trends. The species composition within the 2010 fenced area gradually shifted to greater similarity with the species composition reported in 1981. The plant community in the 2011 fenced area was slower to recover. Compositions of plant communities outside the fenced areas hardly changed from 2011 to 2015. Chao’s dissimilarity index decreased over time between the plant community surveyed between 2011 and 2015 and the past plant community in 1981 within the exclosures, and was higher in the 2011 fenced area than in the 2010 fenced area. In conclusion, we show that the reduction of graminoids and the time after exclosure installation were important for plant community recovery from deer grazing damage. A delay in exclosure installation of one year could result in a delay in plant community recovery of more than one year.

scholarly journals Divergent impact of grazing on plant communities of created wetlands with varying hydrology and antecedent land use

2020 ◽  
Author(s):  
Kimberly A. Lodge ◽  
Anna Christina Tyler
Keyword(s):  
Land Use ◽  
Plant Communities ◽  
Nutrient Availability ◽  
Invasive Plant ◽  
Plant Cover ◽  
Ecosystem Functions ◽  
Created Wetlands ◽  
Grazing Impacts ◽  
Seasonally Flooded ◽  
The Impact

AbstractDestruction of natural wetlands has warranted the creation of wetlands to mitigate the reduction of valuable ecosystem functions and services. However, the complex interactions between key drivers of wetland community structure – hydrology, nutrient availability and herbivory – makes creation of functional wetland replacements challenging. We examined interactions among these drivers, and their impacts on plant communities and soil characteristics in two created wetlands with different hydrology and land use histories: a shallow emergent marsh on a previous gravel depository and a seasonally flooded marsh on a former cattle pasture. In paired plots open to or protected from large wetland grazers we observed seasonal variation in grazing impacts on plant communities and an increase in effect size over time. At the permanently flooded marsh with high grazing waterfowl densities and low nutrients, open plots had significantly reduced plant growth and diversity, and an increase in submerged vegetation. In contrast, grazer density was lower and nutrients were higher in the seasonally flooded marsh, where grazer access enhanced plant diversity and reduced invasive plant cover. These results suggest the possibility of long-term grazer-induced shifts in community composition and delivery of key ecosystem services in young, vulnerable created wetlands. To improve created wetland design and function, we suggest that in addition to hydrologic conditions, the impact of prior land use on present nutrient availability be considered. Further, enhanced heterogeneity of spatial and bathymetric structure can provide conditions for diverse plant communities and balanced habitat use by wetland grazers.

Kyiv park "Nivki" and "Teremki" forests and ecological analysis of their habitats

2014 ◽  
Vol 25 (3-4) ◽  
pp. 53-68
Author(s):  
I. V. Goncharenko ◽  
H. M. Holyk
Keyword(s):  
Standard Deviation ◽  
Species Composition ◽  
Human Impact ◽  
Soil Nitrogen ◽  
Beta Diversity ◽  
Plant Cover ◽  
Alpha Diversity ◽  
Light Regime ◽  
Individual Species ◽  
Anthropogenic Pressure

Cenotic diversity and leading ecological factors of its floristic differentiation were studied on an example of two areas – Kyiv parks "Nivki" and "Teremki". It is shown that in megalopolis the Galeobdoloni-Carpinetum impatientosum parviflorae subassociation is formed under anthropogenic pressure on the typical ecotope of near-Dnieper hornbeam oak forests on fresh gray-forest soils. The degree of anthropogenic transformation of cenofloras can be estimated by the number of species of Robinietea and Galio-Urticetea classes, as well as neophytes and cultivars. Phytoindication for hemeroby index may be also used in calculation. We propose the modified index of biotic dispersion (normalized by alpha-diversity) for the estimation of ecophytocenotic range (beta-diversity) of releves series. We found that alpha-diversity initially increases (due to the invasion of antropophytes) at low level of antropogenic pressure, then it decreases (due to the loss of aboriginal species) secondarily with increasing of human impact. Also we found that beta-diversity (differential diversity) decreases, increasing homogeneity of plant cover, under the influence of anthropogenic factor. Vegetation classification was completed by a new original method of cluster analysis, designated as DRSA («distance-ranked sorting assembling»). The classification quality is suggested to be validated on the "seriation" diagram, which is а distance matrix between objects with gradient filling. Dark diagonal blocks confirm clusters’ density (intracluster compactness), uncolored off-diagonal blocks are evidence in favor of clusters’ isolation (intercluster distinctness). In addition, distinction of clusters (syntaxa) in ordination area suggests their independence. For phytoindication we propose to include only species with more than 10% constancy. Furthermore, for the description of syntaxonomic amplitude we suggest to use 25%-75% interquartile scope instead of mean and standard deviation. It is shown that comparative analysis of syntaxa for each ecofactor is convenient to carry out by using violin (bulb) plots. A new approach to the phytoindication of syntaxa, designated as R-phytoindication, was proposed for our study. In this case, the ecofactor values, calculated for individual releves, are not taken into account, however, the composition of cenoflora with species constancies is used that helps us to minimize for phytoindication the influence of non-typical species. We suggested a syntaxon’s amplitude to be described by more robust statistics: for the optimum of amplitude (central tendency) – by a median (instead of arithmetic mean), and for the range of tolerance – by an interquartile scope (instead of standard deviation). We assesses amplitudes of syntaxa by phytoindication method for moisture (Hd), acidity (Rc), soil nitrogen content (Nt), wetting variability (vHd), light regime (Lc), salt regime (Sl). We revealed no significant differences on these ecofactors among ecotopes of our syntaxa, that proved the variant syntaxonomic rank for all syntaxa. We found that the core of species composition of our phytocenoses consists of plants with moderate requirements for moisture, soil nitrogen, light and salt regime. We prove that the leading factor of syntaxonomic differentiation is hidden anthropogenic, which is not subject to direct measurement. But we detect that hidden factor of "human pressure" was correlated with phytoindication parameters (variables) that can be measured "directly" by species composition of plant communities. The most correlated factors were ecofactors of soil nitrogen, wetting variability, light regime and hemeroby. The last one is the most indicative empirically for the assessment of "human impact". We establish that there is a concept of «hemeroby of phytocenosis» (tolerance to human impact), which can be calculated approximately as the mean or the median of hemeroby scores of individual species which are present in it.

Long-term dynamics and destruction of marsh vegetation in the Kolokolkova Bay of the Barents Sea

2012 ◽  
pp. 66-77 ◽  
Author(s):  
I. A. Lavrinenko ◽  
O. V. Lavrinenko ◽  
D. V. Dobrynin
Keyword(s):  
Species Composition ◽  
Plant Communities ◽  
Barents Sea ◽  
Mean Value ◽  
Marsh Vegetation ◽  
Composition And Structure ◽  
The Mean ◽  
Species Composition And Structure

The satellite images show that the area of marshes in the Kolokolkova bay was notstable during the period from 1973 up to 2011. Until 2010 it varied from 357 to 636 ha. After a severe storm happened on July 24–25, 2010 the total area of marshes was reduced up to 43–50 ha. The mean value of NDVI for studied marshes, reflecting the green biomass, varied from 0.13 to 0.32 before the storm in 2010, after the storm the NDVI decreased to 0.10, in 2011 — 0.03. A comparative analysis of species composition and structure of plant communities described in 2002 and 2011, allowed to evaluate the vegetation changes of marshes of the different topographic levels. They are fol­lowing: a total destruction of plant communities of the ass. Puccinellietum phryganodis and ass. Caricetum subspathaceae on low and middle marches; increasing role of halophytic species in plant communities of the ass. Caricetum glareosae vic. Calamagrostis deschampsioides subass. typicum on middle marches; some changes in species composition and structure of plant communities of the ass. Caricetum glareosae vic. Calamagrostis deschampsioides subass. festucetosum rubrae on high marches and ass. Parnassio palustris–Salicetum reptantis in transition zone between marches and tundra without changes of their syntaxonomy; a death of moss cover in plant communities of the ass. Caricetum mackenziei var. Warnstorfia exannulata on brackish coastal bogs. The possible reasons of dramatic vegetation dynamics are discussed. The dating of the storm makes it possible to observe the directions and rates of the succession of marches vegetation.

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