scholarly journals Spatiotemporal Response of Vegetation to Rainfall and Temperature fluctuations in the Sahel. Case study in the Forest Reserve of Fina, Mali

Author(s):  
Karamoko Sanogo ◽  
Birhanu B. Zemadim ◽  
Souleymane Sanogo ◽  
Ashatu Abdulkadiri ◽  
Abdramane BA

Forests constitute a key component of the Earth system but the sustainability of the forest reserves in the semi-arid zone is a real concern since its vegetation is very sensitive to the climate fluctuation. The understanding of the mechanisms for the interaction vegetation-climate is poorly studied in the context of African Sahel. In this study, the characteristics of the vegetation response to the fluctuations of precipitation and temperature is determined for the forest reserve of Fina. Rainfall estimates, air temperature and NDVI are used to establish the lag correlations between fluctuations of vegetation and climate variables at both seasonal and interannual bases. Results shows increasing tendency of NDVI started from the 1990s coinciding the recovery of the rainfall from the 1980s drought and the obtained correlation(r=0.66) is statistically significant (pvalue<0.01). The strongest responses of vegetation to rainfall and temperature fluctuations were found after 30 and 15 days, respectively. Moreover, at shorter time lag (e.g. 15 days) more pronounced vegetation responses to both rainfall and temperature were found in agricultural dominated land while at longer time lag (e.g. 30 days) stronger response was observed in Bare dominated land. The vegetation response to the climate fluctuation is modulated by the land use/cover dynamics. Keywords: NDVI, Rainfall, Air temperature, vegetation response, Fina Forest Reserve, Mali.

2021 ◽  
Vol 13 (11) ◽  
pp. 6250
Author(s):  
Karamoko Sanogo ◽  
Birhanu Zemadim Birhanu ◽  
Souleymane Sanogo ◽  
Abdulkadir Aishetu ◽  
Abdramane Ba

Forests constitute a key component of the Earth system but the sustainability of the forest reserves in the semi-arid zone is a real concern since its vegetation is very sensitive to the climate fluctuation. The understanding of the mechanisms for the vegetation–climate interaction is poorly studied in the context of African Sahel. In this study, the characteristics of the vegetation response to the fluctuations of precipitation and temperature is determined for the forest reserve of Fina. Rainfall estimates, air temperature and NDVI were re-gridded to a same spatial resolution and standardized with respect to their respective long-term mean. Lag-correlations analysis was used to estimate lag times between changes of climate variables and vegetation response at both seasonal and interannual bases. Results show increasing tendency of NDVI started from the 1990s coinciding the recovery of the rainfall from the 1980s drought, and the obtained correlation (r = 0.66) is statistically significant (p value < 0.01). The strongest responses of vegetation to rainfall and temperature fluctuations were found after 30 and 15 days, respectively. Moreover, at a shorter time lag (e.g., 15 days), more pronounced vegetation responses to both rainfall and temperature were found in agriculturally dominated land while at a longer time lag (e.g., 30 days), a stronger response was observed in Bare-dominated land. The vegetation response to the climate fluctuation is modulated by the land-use/cover dynamics.


2016 ◽  
Vol 20 (3) ◽  
pp. 405-429 ◽  
Author(s):  
R.B. Davenport ◽  
P.H. May ◽  
P. Nogueira ◽  
P.C. Nunes

ABSTRACT Agrarian reform settlements have recently been identified as a major contributor to ongoing deforestation in the Brazilian Amazon. Collective forest reserves were established in some settlements to thwart forest loss, but settlers usually do not recognize forest commons, opting instead for continued private accumulation through forest clearing, or a "non-commons" tragedy. Pathways toward ensuring the viability of common-pool management in settlements remain unclear. Our case study focused on two similarly sized settlements in neighboring municipalities in Northwest Mato Grosso, Brazil, each with formally designated collective forest areas. In one, deforestation shifted into the collective reserve and intensified; in the other, deforestation stabilized and the collective reserve was protected. In the latter, settlers understood their collective forest reserve as a commonly held asset, with two commercially viable settlement cooperatives involved in Brazil nut (Bertholletia excelsa) extractivism and added value processing. We analyze differences between the two settlements using Elinor Ostrom's framework for analysis of socio-ecological systems, and identify the locally applied policy mix ensuring the viability of a forest commons. The study concludes that "top-down" efforts to institutionalize collective governance over remaining forests will likely fail in most settlements, without a focus on alternative livelihood opportunities synergetic with forest tenure.


2014 ◽  
Vol 8 (2) ◽  
pp. 183-194 ◽  
Author(s):  
Gianina Maria Cojoc ◽  
Gheorghe Romanescu ◽  
Alina Tirnovan

Abstract The increase in most components of the climate over the past 50 years, including air and water temperature, is a real phenomenon, as attested by the numerous specialized researches according to IPCC (2013). The water temperature is one of the most important climatic components in analyzing the hydrological regime of the Bistrita River (Romania). The thermal regime of the Bistrita River basin and the frost phenomena associated with the risk factor are particularly important and frequently appear in this area. In recent years, under the Siret Water Basin Administration, this parameter was permanently monitored, so we could do an analysis, which shows that the water temperature fluctuations, influenced by air temperature, lead to the emergence of the ice jam phenomenon. The present study aims to analyze the water temperature, as compared to the air temperature, and the effect of these components on the liquid flow regime (the values were recorded at the hydrological stations on the main course of the Bistrita River). The negative effects resulted from the ice jam phenomenon require developing methods of damage prevention and defense. The frost phenomena recorded after the construction of the Bicaz dam are analyzed in this article


2020 ◽  
pp. 105-112
Author(s):  
Olujobi O. J. ◽  
Olajuyigbe B. J.

In the past, conservation effort has primarily focused on establishment of forest reserves for timber production, with minimal or no consideration to how these natural resources will help sustain or improve livelihoods of adjoining communities. This study examined the contribution of Aramoko forest reserve to the livelihoods of the adjoining communities in Ekiti State. One hundred and twenty pre-tested questionnaires were administered among the products collectors in the study area. Data collected were analysed and the result showed that 78.3 % of the respondents are married with 52.3 % of them male, while 50.8 % of the respondents aged between 51-70 years with 64.1 % having at least secondary education. Twenty-five (25) different products were collected by the respondents in the study area. These products include among others; timber with highest frequency of (120) followed by herbal plants (115), Archantina marginata (105), Thaumatococcus danielli (89), Bridelia ferruginea (70) and Irvingia garbonensis (65). The use of motor cycle accounted for 41.4 % of the respondents means of transportation, while 31.3 % of the respondents sell their product in bit at the village market. Picking, digging, plucking, cutting and uprooting were methods used for harvesting by the respondents while illegal felling (24 %) and indiscriminate bush burning (22.4 %) were the major conservation problem in the study area. Specifically, some of the products harvested are used for food, medicine, fuelwood, herbs and cultural purposes. The study recommends that research should be conducted into how these products can be artificially raised in the nursery for plantation establishment.


2021 ◽  
Vol 13 (5) ◽  
pp. 923
Author(s):  
Qianqian Sun ◽  
Chao Liu ◽  
Tianyang Chen ◽  
Anbing Zhang

Vegetation fluctuation is sensitive to climate change, and this response exhibits a time lag. Traditionally, scholars estimated this lag effect by considering the immediate prior lag (e.g., where vegetation in the current month is impacted by the climate in a certain prior month) or the lag accumulation (e.g., where vegetation in the current month is impacted by the last several months). The essence of these two methods is that vegetation growth is impacted by climate conditions in the prior period or several consecutive previous periods, which fails to consider the different impacts coming from each of those prior periods. Therefore, this study proposed a new approach, the weighted time-lag method, in detecting the lag effect of climate conditions coming from different prior periods. Essentially, the new method is a generalized extension of the lag-accumulation method. However, the new method detects how many prior periods need to be considered and, most importantly, the differentiated climate impact on vegetation growth in each of the determined prior periods. We tested the performance of the new method in the Loess Plateau by comparing various lag detection methods by using the linear model between the climate factors and the normalized difference vegetation index (NDVI). The case study confirmed four main findings: (1) the response of vegetation growth exhibits time lag to both precipitation and temperature; (2) there are apparent differences in the time lag effect detected by various methods, but the weighted time-lag method produced the highest determination coefficient (R2) in the linear model and provided the most specific lag pattern over the determined prior periods; (3) the vegetation growth is most sensitive to climate factors in the current month and the last month in the Loess Plateau but reflects a varied of responses to other prior months; and (4) the impact of temperature on vegetation growth is higher than that of precipitation. The new method provides a much more precise detection of the lag effect of climate change on vegetation growth and makes a smart decision about soil conservation and ecological restoration after severe climate events, such as long-lasting drought or flooding.


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