TY  - JOUR
A1  - Guo, Tong
A1  - Weise, Hanna
A1  - Fiedler, Sebastian
A1  - Lohmann, Dirk
A1  - Tietjen, Britta
T1  - The role of landscape heterogeneity in regulating plant functional diversity under different precipitation and grazing regimes in semi-arid savannas
JF  - Ecological modelling : international journal on ecological modelling and engineering and systems ecolog
N2  - 1. Savanna systems exhibit a high plant functional diversity. While aridity and livestock grazing intensity have been widely discussed as drivers of savanna vegetation composition, physical soil properties have received less attention. Since savannas can show local differences in soil properties, these might act as environmental filters and affect plant diversity and ecosystem functioning at the patch scale. However, research on the link between savanna vegetation diversity and ecosystem function is widely missing. 2. In this study, we aim at understanding the impact of local heterogeneity in soil conditions on plant diversity and on ecosystem functions. For this, we used the ecohydrological savanna model EcoHyD. The model simulates the fate of multiple plant functional types and their interactions with local biotic and abiotic conditions. We applied the model to a set of different landscapes under a wide range of livestock grazing and precipitation scenarios to assess the impact of local heterogeneity in soil conditions on the composition and diversity of plant functional types and on ecosystem functions. 3. Comparisons between homogeneous and heterogeneous landscapes revealed that landscape soil heterogeneity allowed for a higher functional diversity of vegetation under conditions of high competition, i.e. scenarios of low grazing stress. However, landscape heterogeneity did not have this effect under low grazing stress in combination with high mean annual precipitation. Further, landscape heterogeneity led to a higher community biomass, especially for lower rainfall conditions, but also dependent on grazing stress. Total transpiration of the plant community decreased in heterogeneous landscapes under arid conditions. 4. This study highlights that local soil conditions interact with precipitation and grazing in driving savanna vegetation. It clearly shows that vegetation diversity and resulting ecosystem functioning can be driven by landscape heterogeneity. We therefore suggest that future research on ecosystem functioning of savanna systems should focus on the links between local environmental conditions via plant functional diversity to ecosystem functioning.
KW  - Plant functional type
KW  - Trait diversity
KW  - Ecosystem functioning
KW  - Plant coexistence
KW  - Soil texture
KW  - Ecohydrological model
Y1  - 2018
U6  - https://doi.org/10.1016/j.ecolmodel.2018.04.009
SN  - 0304-3800
SN  - 1872-7026
VL  - 379
SP  - 1
EP  - 9
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Bernhard, Nadine
A1  - Moskwa, Lisa-Marie
A1  - Schmidt, Karsten
A1  - Oeser, Ralf Andreas
A1  - Aburto, Felipe
A1  - Bader, Maaike Y.
A1  - Baumann, Karen
A1  - von Blanckenburg, Friedhelm
A1  - Boy, Jens
A1  - van den Brink, Liesbeth
A1  - Brucker, Emanuel
A1  - Buedel, Burkhard
A1  - Canessa, Rafaella
A1  - Dippold, Michaela A.
A1  - Ehlers, Todd
A1  - Fuentes, Juan P.
A1  - Godoy, Roberto
A1  - Jung, Patrick
A1  - Karsten, Ulf
A1  - Koester, Moritz
A1  - Kuzyakov, Yakov
A1  - Leinweber, Peter
A1  - Neidhardt, Harald
A1  - Matus, Francisco
A1  - Mueller, Carsten W.
A1  - Oelmann, Yvonne
A1  - Oses, Romulo
A1  - Osses, Pablo
A1  - Paulino, Leandro
A1  - Samolov, Elena
A1  - Schaller, Mirjam
A1  - Schmid, Manuel
A1  - Spielvogel, Sandra
A1  - Spohn, Marie
A1  - Stock, Svenja
A1  - Stroncik, Nicole
A1  - Tielboerger, Katja
A1  - Uebernickel, Kirstin
A1  - Scholten, Thomas
A1  - Seguel, Oscar
A1  - Wagner, Dirk
A1  - Kühn, Peter
T1  - Pedogenic and microbial interrelations to regional climate and local topography
BT  - New insights from a climate gradient (arid to humid) along the Coastal Cordillera of Chile
JF  - Catena : an interdisciplinary journal of soil science, hydrology, geomorphology focusing on geoecology and landscape evolution
N2  - The effects of climate and topography on soil physico-chemical and microbial parameters were studied along an extensive latitudinal climate gradient in the Coastal Cordillera of Chile (26 degrees-38 degrees S). The study sites encompass arid (Pan de Azucar), semiarid (Santa Gracia), mediterranean (La Campana) and humid (Nahuelbuta) climates and vegetation, ranging from arid desert, dominated by biological soil crusts (biocrusts), semiarid shrubland and mediterranean sclerophyllous forest, where biocrusts are present but do have a seasonal pattern to temperate-mixed forest, where biocrusts only occur as an early pioneering development stage after disturbance. All soils originate from granitic parent materials and show very strong differences in pedogenesis intensity and soil depth. Most of the investigated physical, chemical and microbiological soil properties showed distinct trends along the climate gradient. Further, abrupt changes between the arid northernmost study site and the other semi-arid to humid sites can be shown, which indicate non-linearity and thresholds along the climate gradient. Clay and total organic carbon contents (TOC) as well as Ah horizons and solum depths increased from arid to humid climates, whereas bulk density (BD), pH values and base saturation (BS) decreased. These properties demonstrate the accumulation of organic matter, clay formation and element leaching as key-pedogenic processes with increasing humidity. However, the soils in the northern arid climate do not follow this overall latitudinal trend, because texture and BD are largely controlled by aeolian input of dust and sea salts spray followed by the formation of secondary evaporate minerals. Total soil DNA concentrations and TOC increased from arid to humid sites, while areal coverage by biocrusts exhibited an opposite trend. Relative bacterial and archaeal abundances were lower in the arid site, but for the other sites the local variability exceeds the variability along the climate gradient. Differences in soil properties between topographic positions were most pronounced at the study sites with the mediterranean and humid climate, whereas microbial abundances were independent on topography across all study sites. In general, the regional climate is the strongest controlling factor for pedogenesis and microbial parameters in soils developed from the same parent material. Topographic position along individual slopes of limited length augmented this effect only under humid conditions, where water erosion likely relocated particles and elements downward. The change from alkaline to neutral soil pH between the arid and the semi-arid site coincided with qualitative differences in soil formation as well as microbial habitats. This also reflects non-linear relationships of pedogenic and microbial processes in soils depending on climate with a sharp threshold between arid and semi-arid conditions. Therefore, the soils on the transition between arid and semi-arid conditions are especially sensitive and may be well used as indicators of long and medium-term climate changes. Concluding, the unique latitudinal precipitation gradient in the Coastal Cordillera of Chile is predestined to investigate the effects of the main soil forming factor - climate - on pedogenic processes.
KW  - Climate
KW  - Topography
KW  - Soil texture
KW  - Total organic carbon
KW  - Carbon isotope ratio (delta C-13(TOC))
KW  - Microbial abundance
Y1  - 2018
U6  - https://doi.org/10.1016/j.catena.2018.06.018
SN  - 0341-8162
SN  - 1872-6887
VL  - 170
SP  - 335
EP  - 355
PB  - Elsevier
CY  - Amsterdam
ER  -