Decomposition and Nutrient Cycling in Disturbed Arid Ecosystems

Author(s):  
Walter G. Whitford
2019 ◽  
Vol 286 (1914) ◽  
pp. 20191647 ◽  
Author(s):  
Nevo Sagi ◽  
José M. Grünzweig ◽  
Dror Hawlena

Nutrient cycling in most terrestrial ecosystems is controlled by moisture-dependent decomposer activity. In arid ecosystems, plant litter cycling exceeds rates predicted based on precipitation amounts, suggesting that additional factors are involved. Attempts to reveal these factors have focused on abiotic degradation, soil–litter mixing and alternative moisture sources. Our aim was to explore an additional hypothesis that macro-detritivores control litter cycling in deserts. We quantified the role different organisms play in clearing plant detritus from the desert surface, using litter baskets with different mesh sizes that allow selective entry of micro-, meso- or macrofauna. We also measured soil nutrient concentrations in increasing distances from the burrows of a highly abundant macro-detritivore, the desert isopod Hemilepistus reaumuri . Macro-detritivores controlled the clearing of plant litter in our field site. The highest rates of litter removal were measured during the hot and dry summer when isopod activity peaks and microbial activity is minimal. We also found substantial enrichment of inorganic nitrogen and phosphorous near isopod burrows. We conclude that burrowing macro-detritivores are important regulators of litter cycling in this arid ecosystem, providing a plausible general mechanism that explains the unexpectedly high rates of plant litter cycling in deserts.


Fruits ◽  
2002 ◽  
Vol 57 (3) ◽  
pp. 143-151 ◽  
Author(s):  
Sajan Kurien ◽  
Paickattumana Suresh Kumar ◽  
Nerukavil Varieth Kamalam ◽  
Pallacken Abdul Wahid

2018 ◽  
Vol 57 (3) ◽  
pp. 307-321 ◽  
Author(s):  
Manzoor Hussain Memon ◽  
Naveed Aamir ◽  
Nadeem Ahmed

Climate change has now become a reality that has intensified the sufferings of people living in arid ecosystems. Decrease in rainfall, rise in temperature and increase in the frequency of extreme events are some of the changes observed in the semi-arid desert of district Tharparkar. For thousands of years, people of Tharparkar are coping with drought and aridity of the land by using indigenous knowledge. However, global changes in the climatic pattern and deterioration of social and economic conditions have pushed the inhabitants of this arid region into extreme vulnerable situation. This paper investigates the link between climate-induced natural disasters, particularly drought, from the perspective of changing climate patterns which have resulted in food insecurity and water scarcity. The paper analyses the rainfall pattern in the last 38 years—dividing it into two periods i.e. from 1975-1994 and 1995-2014. The findings of the paper have challenged the prevailing notions about aridity and rainfall patterns in Tharparkar district. The research found that there is an increase in average annual precipitation in the district with erratic patterns. Thus, the nature of drought in the district has changed from its historic pattern of less or no rainfall to more but erratic rainfall that is more threatening to livelihoods of the people that in turn have multiplier effect on water and food insecurity. In particularly, women are more vulnerable in the absence of social security and lack of basic necessities for their survival amidst drought. For instance, traditionally the burden of managing water resources falls on women, which leads to an increased work load during the time of drought and also water scarcity. JEL Classification: Q54, Q56, Q25, I30 Keywords: Climate, Environment and Development, Drought, Water, Poverty


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