ROLE OF EXTREME WINDS SHAPING COASTAL ARID ECOSYSTEMS: RELATION BETWEEN SOIL AND DUST IN COASTAL NAMIBIA

2019 ◽  
Author(s):  
James King ◽  
◽  
Amélie Chaput ◽  
Paola Formenti
Keyword(s):  
Arid Ecosystems ◽  
Extreme Winds

scholarly journals Soil moisture dominates dryness stress on ecosystem production globally

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Laibao Liu ◽  
Lukas Gudmundsson ◽  
Mathias Hauser ◽  
Dahe Qin ◽  
Shuangcheng Li ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Vapor Pressure Deficit ◽  
Arid Ecosystems ◽  
Drought Risk ◽  
Relative Role ◽  
Ecosystem Responses ◽  
Vegetation Growth ◽  
Ecosystem Production ◽  
Valid Data

Abstract Dryness stress can limit vegetation growth and is often characterized by low soil moisture (SM) and high atmospheric water demand (vapor pressure deficit, VPD). However, the relative role of SM and VPD in limiting ecosystem production remains debated and is difficult to disentangle, as SM and VPD are coupled through land-atmosphere interactions, hindering the ability to predict ecosystem responses to dryness. Here, we combine satellite observations of solar-induced fluorescence with estimates of SM and VPD and show that SM is the dominant driver of dryness stress on ecosystem production across more than 70% of vegetated land areas with valid data. Moreover, after accounting for SM-VPD coupling, VPD effects on ecosystem production are much smaller across large areas. We also find that SM stress is strongest in semi-arid ecosystems. Our results clarify a longstanding question and open new avenues for improving models to allow a better management of drought risk.

The role of ultraviolet radiation in litter decomposition in arid ecosystems

2006 ◽  
Vol 34 (1) ◽  
pp. 82-91 ◽  
Author(s):  
M.E. Gallo ◽  
R.L. Sinsabaugh ◽  
S.E. Cabaniss
Keyword(s):  
Ultraviolet Radiation ◽  
Litter Decomposition ◽  
Arid Ecosystems

scholarly journals The role of photo- and thermal degradation for CO<sub>2</sub> and CO fluxes in an arid ecosystem

2015 ◽  
Vol 12 (13) ◽  
pp. 4161-4174 ◽  
Author(s):  
H. van Asperen ◽  
T. Warneke ◽  
S. Sabbatini ◽  
G. Nicolini ◽  
D. Papale ◽  
...  
Keyword(s):  
Thermal Degradation ◽  
Field Experiment ◽  
Arid Ecosystems ◽  
Gradient System ◽  
Potential Importance ◽  
Abiotic Degradation ◽  
Field Samples ◽  
Different Temperatures ◽  
Ftir Spectrometer

Abstract. Recent studies have suggested the potential importance of abiotic degradation in arid ecosystems. In this study, the role of photo- and thermal degradation in ecosystem CO2 and CO exchange is assessed. A field experiment was performed in Italy using an FTIR-spectrometer (Fourier Transform Infrared) coupled to a flux gradient system and to flux chambers. In a laboratory experiment, field samples were exposed to different temperatures and radiation intensities. No photodegradation-induced CO2 and CO fluxes of in literature suggested magnitudes were found in the field nor in the laboratory study. In the laboratory, we measured CO2 and CO fluxes that were derived from thermal degradation. In the field experiment, CO uptake and emission have been measured and are proposed to be a result of biological uptake and abiotic thermal degradation-production. We suggest that previous studies, addressing direct photodegradation, have overestimated the role of photodegradation and observed fluxes might be due to thermal degradation, which is an indirect effect of radiation. The potential importance of abiotic decomposition in the form of thermal degradation, especially for arid regions, should be considered in future studies.

The role of landscape morphology on soil moisture variability in semi‐arid ecosystems

2020 ◽  
Author(s):  
Ankur Srivastava ◽  
Patricia M. Saco ◽  
Jose F. Rodriguez ◽  
Nikul Kumari ◽  
Kwok Pan Chun ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Arid Ecosystems ◽  
Landscape Morphology ◽  
Soil Moisture Variability ◽  
Semi Arid ◽  
Moisture Variability

scholarly journals Role of biomass spread in vegetation pattern formation within arid ecosystems

2008 ◽  
Vol 44 (10) ◽  
Author(s):  
Sally Thompson ◽  
Gabriel Katul ◽  
Sean M. McMahon
Keyword(s):  
Pattern Formation ◽  
Vegetation Pattern ◽  
Arid Ecosystems

scholarly journals The role of photo- and thermal degradation for CO<sub>2</sub> and CO fluxes in an arid ecosystem

2015 ◽  
Vol 12 (3) ◽  
pp. 2429-2457 ◽  
Author(s):  
H. van Asperen ◽  
T. Warneke ◽  
S. Sabbatini ◽  
G. Nicolini ◽  
D. Papale ◽  
...  
Keyword(s):  
Thermal Degradation ◽  
Arid Regions ◽  
Arid Ecosystems ◽  
Gradient System ◽  
Potential Importance ◽  
Abiotic Degradation ◽  
Field Samples ◽  
Different Temperatures ◽  
Ftir Spectrometer

Abstract. Recent studies have suggested the potential importance of abiotic degradation in arid ecosystems. In this study, the role of photo- and thermal degradation in ecosystem CO2 and CO exchange is assessed. A field experiment was performed in Italy using a FTIR-spectrometer coupled to a flux gradient system and to flux chambers. In a laboratory experiment, field samples were exposed to different temperatures and radiation intensities. No photodegradation-induced CO2 and CO fluxes were found in the field and in the laboratory study. In the laboratory, thermal degradation fluxes for CO2 and CO have been observed. In the field, CO uptake and emission have been observed and are proposed to be a result of biological uptake and abiotic thermal degradation-production. We suggest that previous studies, studying direct photodegradation, have overestimated the role of photodegradation and observed fluxes might be due to thermal degradation, which is an indirect effect of radiation. The potential importance of abiotic decompostion in the form of thermal degradation, especially for arid regions, should be considered in future studies.

scholarly journals Does management of a top carnivore influence the response of mesopredators and prey to rainfall in arid ecosystems? Evidence for a Baseline Density theory

2021 ◽  
Author(s):  
Renee L. Brawata
Keyword(s):  
Primary Productivity ◽  
Relative Strength ◽  
Trophic Levels ◽  
Arid Ecosystems ◽  
Top Down ◽  
Down Regulation ◽  
Bottom Up ◽  
Rate Of Increase ◽  
Abundance And Diversity

ABSTRACT The removal of apex carnivores from ecosystems can impact the abundance and diversity of species in lower trophic levels. In arid ecosystems, where “bottom up” forces of primary productivity and resource availability strongly affect trophic interactions, the role of “top down” effects is still much debated. This study explored the potential role of an apex predator, the dingo, as a “top down” trophic regulator in Australian arid ecosystems under different levels of primary productivity and dingo management regimes. Consistent with the theory of top down regulation, strong relationships were found between dingo management, dingo activity and fox activity. Dingoes appeared to suppress fox activity where dingoes were uncontrolled or only opportunistically controlled. At sites where dingoes were absent or in low numbers, fox activity was higher, and this inverse relationship persisted regardless of rainfall. The activity of rabbits and small mammals was lower where dingoes were absent and fox activity was high, while the activity of macropods was higher in the absence of dingoes. Feral cat activity did not differ significantly between sites under different dingo management or between years. These results suggest that management of dingoes is a key determinant of fox activity and the activity of some prey under varying levels of productivity. Evidence from this research showed that while the strength of trophic regulation by dingoes may fluctuate, top down effects occurred both prior to and post significant rainfall events. Following this, top down regulation of fox populations during dry periods at sites where dingoes are retained may enable higher and more stable “baseline” densities of small vertebrates, from which a larger and more rapid rate of increase of these prey during the “boom” periods can occur. Understanding the relative strength and interactions of top down and bottom up forces in regulating populations, and under what ecological states the importance of each changes, is important for the long-term conservation of biodiversity in arid regions.

Ecosystem Engineering Effects of Mongolian Marmots (Marmota sibirica) on Terrestrial Arthropod Communities

2021 ◽  
Vol 19 (2) ◽  
pp. 17-30
Author(s):  
Suuri Buyandelger ◽  
◽  
Tojoo Enkhbayar ◽  
Baatargal Otgonbayar ◽  
Myagmar Zulbayar ◽  
...  
Keyword(s):  
Keystone Species ◽  
Soil Nutrient ◽  
Ecosystem Engineering ◽  
Arid Ecosystems ◽  
Arthropod Communities ◽  
Flying Insects ◽  
Animal Community ◽  
Nutrient Profiles ◽  
Marmota Sibirica

The Mongolian marmot (Marmota sibirica) is a large, endangered rodent species that ranges across the steppe regions of Mongolia, and parts of China and Russia. Marmot lives colonially and creates extensive burrow systems that change the soil nutrient profiles and influence plant and animal community composition and productivity. We examined the role of marmots on the diversity and abundance of ground-dwelling and flying insects. We hypothesize that the arthropod communities differ between marmot colonies and surrounding grasslands in diversity and abundance. We trapped 4765 individuals of arthropods representing 178 species of insects and 12 families of spiders. Marmot colony sites differed significantly from off colony sites by communities of ground-dwelling and flying insects. Our findings indicate that abundance and species richness of arthropods are largely associated with marmot burrows, which might be a reason for increased habitat heterogeneity, such as bare ground, specific vegetation structure, and thermoregulatory site by ecosystem engineering. Our results demonstrate that the marmots are keystone species in arid ecosystems, and have complementary, additive effects on steppe arthropod communities.

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