Soil aggregation and soil fraction associated carbon under different vegetation types in a complex landscape

Soil Research ◽  
2019 ◽  
Vol 57 (3) ◽  
pp. 215 ◽  
Author(s):  
Xiaoqing Li ◽  
Iris Vogeler ◽  
Luitgard Schwendenmann
Keyword(s):  
Vegetation Cover ◽  
Vegetation Change ◽  
Soil Characteristics ◽  
Soil Aggregation ◽  
Saturation Deficit ◽  
Density Fractions ◽  
Soil Fraction ◽  
Tussock Grassland ◽  
Complex Landscape ◽  
Native Shrubs

Land cover change has been shown to affect soil characteristics and soil organic carbon (SOC) storage. However, little is known about the driving factors associated with soil carbon (C) stabilisation in complex landscapes. This study was conducted to investigate the effects of both inherent soil characteristics and recent vegetation cover change on soil aggregation and soil fraction associated C in a complex landscape. The specific objectives were: (1) determine bulk soil properties and SOC saturation deficit; (2) quantify soil aggregation, soil size-density fractions, and soil fraction associated C; and (3) identify the factors that influence soil fractions and soil fraction associated C in two adjacent catchments differing in vegetation cover, Central Otago, New Zealand. Catchment GH1 (n = 17 plots) was dominated by tussock grassland and native shrubs. Catchment GH2 (n = 21 plots) was converted from tussock grassland into a pine forest in 1981. The catchments differed in soil texture (e.g. sand content GH1: 62.9%, GH2: 50.7%, P = 0.007), soil SOC stocks (GH1: 5.0 kg C m−2, GH2: 4.3 kg C m−2, P = 0.04), mean weight diameter (MWD) (GH1: 782.3 µm, GH2: 736.5 µm, P = 0.002), and proportion of the macroaggregate heavy fraction (macro_HF) (GH1: 72%, GH2: 55%, P = 0.01). No significant differences were found in SOC saturation deficit (GH1: 14.8 mg g−1, GH2: 13.1 mg g−1, P = 0.13). Dominant vegetation cover explained 21% of the variation in MWD in GH1, whereas silt+clay C content explained 31.6% of the MWD variation in GH2. The macro_HF fraction was negatively correlated with the proportion of silt+clay. Our findings illustrate that physical and chemical soil characteristics are important drivers in such a complex landscape and may have masked the effect of recent vegetation change on soil aggregation, and soil fraction associated C.

scholarly journals Vegetation change (1988–2010) in Camdeboo National Park (South Africa), using fixed-point photo monitoring: The role of herbivory and climate

Koedoe ◽  
2013 ◽  
Vol 55 (1) ◽  
Author(s):  
Mmoto L. Masubelele ◽  
Michael T. Hoffman ◽  
William Bond ◽  
Peter Burdett
Keyword(s):  
South Africa ◽  
Fixed Point ◽  
National Parks ◽  
Vegetation Cover ◽  
National Park ◽  
Vegetation Change ◽  
Growth Form ◽  
Annual Rainfall ◽  
Management Interventions

Fixed-point photo monitoring supplemented by animal census data and climate monitoring potential has never been explored as a long-term monitoring tool for studying vegetation change in the arid and semi-arid national parks of South Africa. The long-term (1988–2010), fixed-point monitoring dataset developed for the Camdeboo National Park, therefore, provides an important opportunity to do this. Using a quantitative estimate of the change in vegetation and growth form cover in 1152 fixed-point photographs, as well as series of step-point vegetation surveys at each photo monitoring site, this study documented the extent of vegetation change in the park in response to key climate drivers, such as rainfall, as well as land use drivers such as herbivory by indigenous ungulates. We demonstrated the varied response of vegetation cover within three main growth forms (grasses, dwarf shrubs [< 1 m] and tall shrubs [> 1 m]) in three different vegetation units and landforms (slopes, plains, rivers) within the Camdeboo National Park since 1988. Sites within Albany Thicket and Dwarf Shrublands showed the least change in vegetation cover, whilst Azonal vegetation and Grassy Dwarf Shrublands were more dynamic. Abiotic factors such as drought and flooding, total annual rainfall and rainfall seasonality appeared to have the greatest influence on growth form cover as assessed from the fixed-point photographs. Herbivory appeared not to have had a noticeable impact on the vegetation of the Camdeboo National Park as far as could be determined from the rather coarse approach used in this analysis and herbivore densities remained relatively low over the study duration.Conservation implications: We provided an historical assessment of the pattern of vegetation and climatic trends that can help evaluate many of South African National Parks’ biodiversity monitoring programmes, especially relating to habitat change. It will help arid parks in assessing the trajectories of vegetation in response to herbivory, climate and management interventions.

scholarly journals A simple approach for monitoring vegetation change using time series remote sensing analysis: A case study from the Thathe Vondo Area in Limpopo Province, South Africa

2021 ◽  
Vol 117 (7/8) ◽  
Author(s):  
Nndanduleni Muavhi
Keyword(s):  
Time Series ◽  
Vegetation Cover ◽  
Vegetation Change ◽  
Vegetation Index ◽  
Simple Approach ◽  
Limpopo Province ◽  
Difference Image ◽  
Normalised Difference Vegetation Index ◽  
Gain And Loss ◽  
The Difference

This study presents a simple approach of spatiotemporal change detection of vegetation cover based on analysis of time series remotely sensed images. The study was carried out at Thathe Vondo Area, which is characterised by episodic variation of vegetation gain and loss. This variation is attributable to timber and tea plantations and their production cycles, which periodically result in either vegetation gain or loss. The approach presented here was implemented on two ASTER images acquired in 2007 and 2017. It involved the combined use of band combination, unsupervised image classification and Normalised Difference Vegetation Index (NDVI) techniques. True colour composite (TCC) images for 2007 and 2017 were created from combination of bands 1, 2 and 3 in red, blue and green, respectively. The difference image of the TCC images was then generated to show the inconsistencies of vegetation cover between 2007 and 2017. For analytical simplicity and interpretability, the difference image was subjected to ISODATA unsupervised classification, which clustered pixels in the difference image into eight classes. Two ISODATA derived classes were interpreted as vegetation gain and one as vegetation loss. These classes were confirmed as regions of vegetation gain and loss by NDVI values of 2007 and 2017. In addition, the polygons of vegetation gain and loss regions were created and superimposed over the TCC images to further demonstrate the spatiotemporal vegetation change in the area. The vegetation change statistics show vegetation gain and loss of 10.62% and 2.03%, respectively, implying a vegetation gain of 8.59% over the selected decade.

scholarly journals Effect of Cover Crop on Carbon Distribution in Size and Density Separated Soil Aggregates

Soil Systems ◽  
2020 ◽  
Vol 4 (1) ◽  
pp. 6 ◽  
Author(s):  
Michael V. Schaefer ◽  
Nathaniel A. Bogie ◽  
Daniel Rath ◽  
Alison R. Marklein ◽  
Abdi Garniwan ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Cover Crop ◽  
Agricultural Soils ◽  
Soil Aggregates ◽  
Fe Oxide ◽  
Δ13c Values ◽  
Density Fractions ◽  
Soil Fraction ◽  
Significant Difference ◽  
Split Field

Increasing soil organic carbon (SOC) stocks in agricultural soils can contribute to stabilizing or even lowering atmospheric greenhouse gas (GHG) concentrations. Cover crop rotation has been shown to increase SOC and provide productivity benefits for agriculture. Here we used a split field design to evaluate the short-term effect of cover crop on SOC distribution and chemistry using a combination of bulk, isotopic, and spectroscopic analyses of size-and density-separated soil aggregates. Macroaggregates (>250 µm) incorporated additional plant material with cover crop as evidenced by more negative δ13C values (−25.4‰ with cover crop compared to −25.1‰ without cover crop) and increased phenolic (plant-like) resonance in carbon NEXAFS spectra. Iron EXAFS data showed that the Fe pool was composed of 17–21% Fe oxide with the remainder a mix of primary and secondary minerals. Comparison of oxalate and dithionite extractions suggests that cover crop may also increase Fe oxide crystallinity, especially in the dense (>2.4 g cm−3) soil fraction. Cover crop δ13C values were more negative across density fractions of bulk soil, indicating the presence of less processed organic carbon. Although no significant difference was observed in bulk SOC on a mass per mass basis between cover and no cover crop fields after one season, isotopic and spectroscopic data reveal enhanced carbon movement between aggregates in cover crop soil.

Area-wide detection and spatial modeling of signs of bioturbation activity along a climate and elevation gradient in Chile using UAV and their dependence on vegetation and soil characteristics

2020 ◽  
Author(s):  
Paulina Grigusova ◽  
Diana Kraus ◽  
Annegret Larsen ◽  
Alexander Klug ◽  
Robin Fischer ◽  
...  
Keyword(s):  
Land Use ◽  
Surface Roughness ◽  
Vegetation Cover ◽  
Point Cloud ◽  
Elevation Gradient ◽  
Soil Characteristics ◽  
Soil Conditions ◽  
Vegetation Density ◽  
Climate Zones ◽  
Semi Arid

&lt;p&gt;The impact of soil dwelling animals on the terrain shaping is assumed to be largely coupled with vegetation and soil characteristics, particularly in arid and semi-arid regions. The vegetation determines the habitat availability by providing necessary resources such as food and shelter while the burrowing activities of soil dwelling animals impacts at the same time soil properties and nutrient fluxes needed for plant growth. This important relationship and feedbacks between bioturbators, vegetation, climate, soil conditions and landscape shaping is to date completely understudied, particularly the dependencies between soil animals and the vegetation cover. Thus, comprehensive studies to gain a detailed understanding are urgently required. Here, we modeled the presence of all signs of bioturbation (burrows, holes and mounds) within a study area of 1 km&lt;sup&gt;2&lt;/sup&gt; with an elevation gradient of 100m height difference in a semi-arid (Santa Gracia, Chile) and Mediterranean (NP La Campana, Chile) zone of coastal Chile using UAV (unmanned aerial vehicle) images. We then compared their relationship between the two climate zones in regard to the vegetation, elevation and soil characteristics. &lt;span&gt;The images were obtained at a flight altitude of 15-60 meters above one study area per each climate zone by means of a Solo quadropter drone equipped with a RGB GoPro camera. Ancillary &lt;/span&gt;&lt;em&gt;&lt;span&gt;in-situ&lt;/span&gt;&lt;/em&gt; &lt;span&gt;data were measured within 10 plots per study area with a size of 10m x 10m. Within the plots, the amount and size of the burrows and mounds as well as the vegetation cover was quantified. In addition, the GPS coordinates of several holes and mounds with a diameter of 10cm and above were measured. Twenty representative soil samples in regard to the land cover, vegetation type and presence of bioturbation activity were taken along the elevation gradient and analyzed for skeleton fraction, soil texture, bulk density and water content. &lt;/span&gt;The RGB images obtained by the drone system were firstly used for a supervised land-use classification and to calculate the vegetation density across the study area. The surface roughness was estimated by creating the point cloud of the area and calculating the standard deviation of the point cloud and original images using moving window of 5x5 pixels/points. The presence of soil animal activity was modeled using random forest where drone images, digital elevation model, surface roughness and land cover characteristics (land use, vegetation density and type) were used as predictors. The results showed modeled spatial distribution of burrows and mounds within the study areas, and a dependence of the predicted bioturbation activity on vegetation density and type as well as on elevation and soil conditions along the elevation gradient at both sites. The dependencies are finally compared between the two climate zones.&lt;/p&gt;

The effects of restoration on vegetation trends: spatiotemporal variability and influencing factors

2018 ◽  
Vol 109 (3-4) ◽  
pp. 473-481 ◽  
Author(s):  
Kun ZHANG ◽  
Yihe LÜ ◽  
Bojie FU ◽  
Ting LI
Keyword(s):  
Spatial Distribution ◽  
Loess Plateau ◽  
Vegetation Cover ◽  
Large Scale ◽  
Vegetation Change ◽  
Linear Process ◽  
Spatiotemporal Variability ◽  
Ecological Change ◽  
The Loess Plateau ◽  
Aid Decision

ABSTRACTSince the ‘Grain to Green Program' was launched in 1999 in the Loess Plateau, China, the processes and patterns of ecological change have become important. Through the use of the fractional vegetation cover (FVC) index, this study examines the spatial distribution and temporal change of vegetation cover in the Loess Plateau during 2000–2014. Over this period more than 60% of the Loess Plateau has remained with little vegetation cover (FVC <30%). The spatial distribution pattern shows an overall increase from the NW to SE. Temporally, the vegetation cover exhibits a general trend of improvement. In 2000–2005, 2000–2010 and 2000–2014, the percentages of restored vegetation (vegetation with significantly increased FVC, P<0.05) were 2, 21 and 52%, respectively. The rate of vegetation cover restoration was highly variable among different bioclimatic zones. The expansion of restored vegetation was greater in the N of the Loess Plateau than in the south. Both human restoration activities and climatic fluctuation influenced the vegetation cover change. The ‘Grain to Green Program' emphasised vegetation restoration. Regional precipitation also had clear effects on vegetation cover. The results of this study reveal that vegetation change shows a non-linear process in response to climate and ecological restoration measures, and that the change gradually emerges over time. This study highlights the importance of considering the spatiotemporal variability in vegetation cover during the implementation of restoration programs, which could aid decision-making for the effective and sustainable management of large-scale restoration programs.

scholarly journals Analysis on vegetation cover changes and the driving factors in the mid-lower reaches of Hanjiang River Basin between 2001 and 2015

2021 ◽  
Vol 13 (1) ◽  
pp. 675-689
Author(s):  
Yunjun Zhan ◽  
Jiemeng Fan ◽  
Tingting Meng ◽  
Zhongwu Li ◽  
Yan Yan ◽  
...  
Keyword(s):  
River Basin ◽  
Human Activities ◽  
Vegetation Cover ◽  
Vegetation Change ◽  
Climatic Factors ◽  
Driving Factors ◽  
Jianghan Plain ◽  
Hanjiang River ◽  
The Impact ◽  
Positive Effect

Abstract The mid-lower reaches of the Hanjiang River Basin, located in the core of economic development in Hubei Province, is an integral part of the Yangtze River Economic Belt. In recent years, the watershed ecosystem has become more sensitive to climate changes and human activities, thus affecting the regional vegetation cover. To maintain a stable watershed ecosystem, it is critical to analyze and evaluate the vegetation change and its response to temperature, precipitation, and human activities in this region. This study, based on the trend analysis, partial correlation analysis, and residual analysis, evaluated the change characteristics of vegetation cover as well as the corresponding driving factors in the basin from 2001 to 2015. The results showed that (1) the overall spatial pattern of vegetation cover in the study area was “high in the west and north, lower on both sides of Hanjiang River, and lowest in the center and southeast,” and the pattern changed parabolically with the increasing elevation. (2) Over the 15 years, vegetation cover in the basin showed an increasing trend, and the increased and decreased areas were 90.72 and 9.23%, respectively. (3) The response of vegetation cover to climatic factors varies greatly depending on the increasing elevation. That is, the lag effect under the impact of temperature disappeared gradually, while it became more evident under the impact of precipitation. (4) On the whole, human activities had a positive effect on the regional vegetation cover. The negative effect in the areas around the Nanyang Basin and the positive effect in most parts of the Jianghan Plain were gradually decreased.

scholarly journals Combined Effects of Wildfire and Vegetation Cover Type on Volcanic Soil (Functions and Properties) in a Mediterranean Region: Comparison of Two Soil Quality Indices

2021 ◽  
Vol 18 (11) ◽  
pp. 5926
Author(s):  
Lucia Santorufo ◽  
Valeria Memoli ◽  
Speranza Claudia Panico ◽  
Giorgia Santini ◽  
Rossella Barile ◽  
...  
Keyword(s):  
Soil Quality ◽  
Vegetation Cover ◽  
Soil Characteristics ◽  
Holm Oak ◽  
Fire Occurrence ◽  
Soil Functions ◽  
Quality Indices ◽  
Weighted Function ◽  
Cover Type ◽  
The Impact

Mediterranean regions are the most impacted by fire in Europe. The effects of fire on soil greatly vary according to several factors such as vegetation cover type, but they are scarcely studied. Therefore, this research aimed at evaluating the combined impacts of fire and vegetation on single soil characteristics and on the overall soil quality and functionality through two soil quality indices, simple additive (SQI) and a weighted function (SQIFUNCT). In order to reach the aims, burnt and unburnt soils were collected under different vegetation cover types (herbs and shrubs, black locust, pine and holm oak) within the Vesuvius National Park. The soils were analyzed for the main abiotic (water and organic matter content, total C, N, Ca, K, Cu and Pb concentrations, C/N ratio) and biotic (microbial and fungal biomasses, basal respiration, β-glucosidase activity) characteristics. On the basis of the investigated soil characteristics, several soil functions (water retention, nutrient supply, contamination content, microorganism habitat and activities), and the soil quality indices were calculated. The results showed that the impact of fire on soil quality and functionality was mediated by the vegetation cover type. In fact, fire occurrence led to a decrease in water and C/N ratio under herbs, a decrease in C concentration under holm oak and a decrease in Cu and Pb concentrations under pine. Although the soil characteristics showed significant changes according to vegetation cover types and fire occurrence, both the additive and weighted function soil quality indices did not significantly vary according to both fire occurrence and the vegetation cover type. Among the different vegetation cover types, pine was the most impacted one.

Tempo-Spatial Characteristics Analysis of Vegetation Cover Change in Inner Mongolia from 2000 to 2011

2014 ◽  
Vol 955-959 ◽  
pp. 3859-3863
Author(s):  
Fu Ying Qin ◽  
Gen Suo Jia ◽  
Jie Yang ◽  
Yu Hai Bao
Keyword(s):  
Vegetation Cover ◽  
Inner Mongolia ◽  
Vegetation Change ◽  
Dynamic Change ◽  
Vegetation Types ◽  
Vegetation Dynamic ◽  
Characteristics Analysis ◽  
Slight Upward Trend ◽  
Reflectivity Data ◽  
Vegetation Cover Change

Annual mean NDVI of different Vegetation types during growing season are extracted from MODIS 8-day composite 500m reflectivity data in Inner Mongolia from 2000 to 2011 to analyze vegetation dynamic change and its spatial variation trends. It is shown that annual mean NDVI of different vegetation types has a slight upward trend during the past 12 years and the overall vegetation cover increases slightly. Area of improved vegetation is larger than degradated area and one third area basically no vegetation change, spatial pattern of vegetation cover change shows evident differences between regions.

New species-group taxa of Glossoscolex (Clitellata: Glossoscolecidae) from Rio Grande do Sul, Brazil

Zootaxa ◽  
2018 ◽  
Vol 4496 (1) ◽  
pp. 548
Author(s):  
MARIE L.C. BARTZ ◽  
SAMUEL W. JAMES ◽  
GERUSA P.K. STEFFEN ◽  
ZAIDA ANTONIOLLI ◽  
RICARDO B. STEFFEN ◽  
...  
Keyword(s):  
New Species ◽  
New Taxa ◽  
Vegetation Cover ◽  
Rio Grande ◽  
Soil Characteristics ◽  
Species Group ◽  
Similar Species ◽  
Rio Grande Do Sul ◽  
Histological Sections ◽  
Group A

Five new species-group taxa of Clitellata of the genus Glossoscolex from Rio Grande do Sul State, Brazil are described in this paper: Glossoscolex (Glossoscolex) riograndensis n. sp. has three subspecies, G. (G.) riograndensis riograndensis, G. (G.) riograndensis pollulus n. ssp., G. (G.) riograndensis nativus n. ssp. The two other new species are named G. (G.) pastivus n. sp., and G. (G.) pampas n. sp. All new species are part of the truncatus species group within the subgenus, characterized by the presence of male pores in segment xvii. A single unnamed specimen, also described here, is deemed to belong to a sixth new species-group taxon of the truncatus group. A tabular character comparison of the new taxa and known and morphologically similar species is given. Information on the habitat, such as vegetation cover and soil characteristics, is given as well. G. (G.) r. riograndensis and G. (G.) r. pollulus had an unusual storage of sperm in the nephridia. Histological sections were performed to verify it.

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