scholarly journals Strontium source and depth of uptake shifts with substrate age in semiarid ecosystems

2015 ◽  
Vol 120 (6) ◽  
pp. 1069-1077 ◽  
Author(s):  
Ashley A. Coble ◽  
Stephen C. Hart ◽  
Michael E. Ketterer ◽  
Gregory S. Newman ◽  
Andrew L. Kowler
Keyword(s):  
Semiarid Ecosystems ◽  
Substrate Age

Hillslope geodiversity improves the resistance of shrubs to prolonged droughts in semiarid ecosystems

2021 ◽  
Vol 188 ◽  
pp. 104462
Author(s):  
Vladislav Dubinin ◽  
Ilan Stavi ◽  
Tal Svoray ◽  
Michael Dorman ◽  
Hezi Yizhaq
Keyword(s):  
Semiarid Ecosystems

Landscape-level variation in forest structure and biogeochemistry across a substrate age gradient in Hawaii

Ecology ◽  
2009 ◽  
Vol 90 (11) ◽  
pp. 3074-3086 ◽  
Author(s):  
Peter Vitousek ◽  
Gregory P. Asner ◽  
Oliver A. Chadwick ◽  
Sara Hotchkiss
Keyword(s):  
Forest Structure ◽  
Level Variation ◽  
Substrate Age ◽  
Substrate Age Gradient ◽  
Landscape Level

Ecohydrology of Arid and Semiarid Ecosystems: An Introduction

2019 ◽  
pp. 1-27 ◽  
Author(s):  
Paolo D’Odorico ◽  
Amilcare Porporato ◽  
Christiane Runyan
Keyword(s):  
Semiarid Ecosystems ◽  
Arid And Semiarid Ecosystems ◽  
Arid And Semiarid

Relationships between C and N availability, substrate age, and natural abundance 13C and 15N signatures of soil microbial biomass in a semiarid climate

2009 ◽  
Vol 41 (8) ◽  
pp. 1605-1611 ◽  
Author(s):  
Jeff S. Coyle ◽  
Paul Dijkstra ◽  
Richard R. Doucett ◽  
Egbert Schwartz ◽  
Stephen C. Hart ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
Natural Abundance ◽  
N Availability ◽  
Soil Microbial ◽  
Semiarid Climate ◽  
C And N ◽  
Substrate Age

scholarly journals Exploiting delayed transitions to sustain semiarid ecosystems after catastrophic shifts

2017 ◽  
Author(s):  
Blai Vidiella, ◽  
Josep Sardanyés ◽  
Ricard V. Solé
Keyword(s):  
Computational Models ◽  
Warning Signal ◽  
Semiarid Ecosystems ◽  
Intervention Method ◽  
Catastrophic Shift ◽  
Future Potential ◽  
Desert Areas ◽  
Standard Models ◽  
Potential Shifts ◽  
Catastrophic Shifts

Semiarid ecosystems (including arid, semiarid and dry-subhumid ecosystems) span more than 40% of extant habitats and a similar percentage of human population. As a consequence of global warming, these habitats face future potential shifts towards the desert state characterized by an accelerated loss of diversity and stability leading to collapse. Such possibility has been raised by several mathematical and computational models, along with several early warning signal methods applied to spatial vegetation patterns. Here we show that just after a catastrophic shift has taken place an expected feature is the presence of a ghost, i.e., a delayed extinction associated to the underlying dynamical flows. As a consequence, a system might exhibit for very long times an apparent stationarity hiding in fact an inevitable collapse. Here we explore this problem showing that the ecological ghost is a generic feature of standard models of green-desert transitions including facilitation. If present, the ghost could hide warning signals, since statistical patterns are not be expected to display growing fluctuations over time. We propose and computationally test a novel intervention method based on the restoration of small fractions of desert areas with vegetation as a way to maintain the fragile ecosystem beyond the catastrophic shift caused by a saddle-node bifurcation, taking advantage of the delaying capacity of the ghost just after the bifurcation.

scholarly journals Can land degradation drive differences in the C exchange of two similar semiarid ecosystems?

2017 ◽  
Author(s):  
Ana López-Ballesteros ◽  
Cecilio Oyonarte ◽  
Andrew S. Kowalski ◽  
Penélope Serrano-Ortiz ◽  
Enrique P. Sánchez-Cañete ◽  
...  
Keyword(s):  
Vadose Zone ◽  
Land Degradation ◽  
C Sequestration ◽  
Future Climate Change ◽  
Striking Difference ◽  
Climate Change Scenarios ◽  
Semiarid Ecosystems ◽  
Growing Seasons ◽  
Soil Variables ◽  
Variable Precipitation

Abstract. The concept of land degradation stems from the loss of an ecosystem's biological productivity, which in turn relies on several degradation processes, such as long-term loss of natural vegetation, depletion of soil nutrients, soil compaction or water and wind erosion, to which drylands are especially vulnerable. Currently, drylands occupy more than one third of the global terrestrial surface and will probably expand under future climate change scenarios. Drylands' key role in the global C balance has been recently demonstrated, but the effects of land degradation on C sequestration by these ecosystems needs further research. In the present study, we compare net carbon exchange, together with satellite data and meteorological, ambient and vadose zone (CO2, water content and temperature) variables, between two nearby (~23 km) experimental sites representing natural (i.e. site of reference) and degraded grazed semiarid grasslands located in SE Spain, via eddy covariance measurements over 6 years, with highly variable precipitation magnitude and distribution. Results show a striking difference in the annual C balances with an average release of 196 ± 40 and −23 ± 20 g C m−2 yr−1 for the degraded and natural sites, respectively. At the seasonal scale, differing patterns in net CO2 fluxes were detected over both growing and dry seasons. As expected, during the growing seasons, greater net C uptake over longer periods was observed in the natural site, however, much greater net C release was measured in the degraded site during drought periods. We tested differences in all monitored meteorological and soil variables and found it most relevant that CO2 at 1.50 m belowground was around 1000 ppm higher in the degraded site. Thus, we believe that subterranean ventilation of this vadose zone CO2, previously observed at both sites, largely drives the differences in C dynamics between them, especially during the dry season maybe due to enhanced subsoil-atmosphere interconnectivity in the degraded site. Overall, the 12 site-years of data allow direct exploration of the roles of climate and land degradation in the biological and non-biological processes that ultimately control the C sequestration capacity of semiarid ecosystems.

scholarly journals Directional climate change and potential reversal of desertification in arid and semiarid ecosystems

2011 ◽  
Vol 18 (1) ◽  
pp. 151-163 ◽  
Author(s):  
Debra P. C. Peters ◽  
Jin Yao ◽  
Osvaldo E. Sala ◽  
John P. Anderson
Keyword(s):  
Climate Change ◽  
Semiarid Ecosystems ◽  
Arid And Semiarid Ecosystems ◽  
Arid And Semiarid

Applications of a hydro-geomorphic (dis)connectivity framework to study vegetation transitions in semiarid ecosystems.

2021 ◽  
Author(s):  
Patricia Saco ◽  
Mariano Moreno-de las Heras ◽  
Jose Rodriguez ◽  
Steven Sandi ◽  
Samira Azadi ◽  
...  
Keyword(s):  
Connectivity Pattern ◽  
Terrestrial Vegetation ◽  
Floodplain Wetlands ◽  
Semiarid Ecosystems ◽  
Positive Feedbacks ◽  
Management Interventions ◽  
Vegetation Water ◽  
Healthy Functioning ◽  
And Function ◽  
Vegetation Encroachment

<p>Changes in hydro-geomorphic connectivity have been previously linked to catastrophic shifts in landscape structures and function leading to irreversible degradation. Here we present evidence and new observations to better understand the link between connectivity of water and sediments and possible phase transitions for the case of semiarid ecosystems at the catchment and hillslope scales.  We first focus on rangelands, where coevolving vegetation and landform structures lead to a distinct connectivity pattern responsible for the healthy functioning of the system. Positive feedbacks, triggered by disturbances in vegetation, water or sediment structures can alter the hydro-geomorphic connectivity leading to degradation. Our results for rangelands in Australia, from both simulations and observations, suggest that an increase in connectivity beyond a threshold may lead to irreversible degradation, meaning that the system return to a functional state is unlikely without extensive management interventions. We also analyse the case of semi-arid floodplain wetlands of the Murray-Darling Basin, where we observe that dis-connectivity during droughts promote terrestrial vegetation encroachment and degradation. Simulations and observations also indicate the presence of thresholds beyond which the recovery of the system is unlikely without interventions.</p>

Agriculture in semiarid ecosystems favors the increase fossorial rodent’s activity in La Pampa, Argentina

2019 ◽  
Vol 65 (3) ◽  
Author(s):  
Ana Paula Álamo Iriarte ◽  
Paolo Daniel Sartor ◽  
Jaime Nicolás Bernardos
Keyword(s):  
Semiarid Ecosystems
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