scholarly journals Fragmentation and Connectivity of Island Forests in Agricultural Mediterranean Environments: A Comparative Study between the Guadalquivir Valley (Spain) and the Apulia Region (Italy)

Forests ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1201
Author(s):  
Pablo J. Hidalgo ◽  
Helena Hernández ◽  
Antonio J. Sánchez-Almendro ◽  
Javier López-Tirado ◽  
Federico Vessella ◽  
...  

Habitat loss and fragmentation are considered some the main threats to biodiversity. Original forests have suffered an accentuated fragmentation and agricultural homogenization, leaving only some areas of natural vegetation, relegated to strongly anthropized disconnected patches (island forests, IFs) in a hostile matrix. These patches of original vegetation could be the key for the design and management of ecological corridors to promote species migration, an essential strategy for meeting the consequences of Global Change. This study proposes a comparative analysis of the fragmentation and connectivity of IFs of Quercus in two typically Mediterranean areas of predominantly agricultural use: the Guadalquivir valley (Spain) and the Apulia region (Italy). A retrospective comparison is also carried out in the Guadalquivir valley. The aim is to develop an objective new methodology to locate the patches of most interest using quantitative and qualitative data. Reference cartography of current island forests of Quercus species was developed from several digital sources and validated with orthoimages and field observations. Fragmentation analysis was based on graph structures using the software Conefor 2.6, a reliable tool for assessment of the role of patches in the landscape. Area and distance were used as node and connector values. Dispersion distance was established as 500 m, based on the maximum dispersion of acorns. Results indicate that the Guadalquivir valley has suffered an intensive fragmentation in recent decades. Both the Guadalquivir and Apulia regions host some IFs with the relevant potential to contribute as core habitats in the creation of connections to other natural protected sites. Many residual IFs in the landscape could contribute as stepping stones in the design and management of ecological corridors. Our methodology highlights the value of IFs to develop assessment strategies using homogenized available digital cartography and common criteria for the dispersion distances in graph theory analysis. The application of this new methodology could help in the management of protected sites using highly fragmented areas to allow the species movement through inhospitable landscapes in a unique opportunity to connect the different protected areas.

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 847
Author(s):  
Yu-Zhe Zhang ◽  
Zhi-Yun Jiang ◽  
Yang-Yang Li ◽  
Zhi-Guang Yang ◽  
Xiao-Hong Wang ◽  
...  

The rapid development of urbanization has caused many ecological issues and greatly threatened the sustainable development of human society. The construction of ecological security patterns (ESPs) offers an effective way to balance ecological conservation and urbanization. This study aimed to take the highly urbanized city of Shenzhen, China, as a study area to construct an urban ESP and put forward suggestions for the urban development of ecological security. Ecological sources were identified through the Habitat Quality module in the InVEST model, and ecological corridors, strategic ecological nodes, and stepping-stone patches were extracted based on the minimum cumulative resistance (MCR) model. These elements together constituted the ESP. In particular, with the results of the continuous decline in the overall habitat quality, this study identified ten ecological sources with superior habitat quality, mainly distributed in rural woodlands, in urban green land, and in forest park patches. An optimized pattern for Shenzhen City with one axis, three belts, and four zones is proposed, with the study area divided into an ecological preservation zone, a limited development zone, an optimized development zone, and a key development zone. Moreover, forty-five ecological corridors were extracted and graded into three levels, presenting a spatial pattern of one axis and three belts. The appropriate widths of these ecological corridors were suggested to be between 30 and 60 m in Shenzhen City. In addition, we identified twenty-five ecological nodes, sixteen ecological fracture points, and sixteen stepping stones to improve the maintenance and construction of the ecological corridor network. More generally, this study demonstrates a scientific approach to identifying ESPs based on habitat quality, and can serve as a reference for the planning of urban ecological function regionalization.


2020 ◽  
Vol 477 (16) ◽  
pp. 3091-3104 ◽  
Author(s):  
Luciana E. Giono ◽  
Alberto R. Kornblihtt

Gene expression is an intricately regulated process that is at the basis of cell differentiation, the maintenance of cell identity and the cellular responses to environmental changes. Alternative splicing, the process by which multiple functionally distinct transcripts are generated from a single gene, is one of the main mechanisms that contribute to expand the coding capacity of genomes and help explain the level of complexity achieved by higher organisms. Eukaryotic transcription is subject to multiple layers of regulation both intrinsic — such as promoter structure — and dynamic, allowing the cell to respond to internal and external signals. Similarly, alternative splicing choices are affected by all of these aspects, mainly through the regulation of transcription elongation, making it a regulatory knob on a par with the regulation of gene expression levels. This review aims to recapitulate some of the history and stepping-stones that led to the paradigms held today about transcription and splicing regulation, with major focus on transcription elongation and its effect on alternative splicing.


2014 ◽  
Author(s):  
Kathryn Buchanan-Howland ◽  
Ruth Rose-Jacobs ◽  
Mark A. Richardson ◽  
Timothy Heeren ◽  
Clara A. Chen ◽  
...  

Author(s):  
Olga Merzlova

One of the measures to eliminate the consequences of the Chernobyl accident was the exclusion of highly contaminated land from agricultural use. Due to the positive dynamics of the radiation situation, the issue of land return becomes relevant. However, in the period of exclusion of these lands the land clearance degradation processes were developing. The second part of the article is devoted to the issue of economic evaluation of the expediency of land return and the mutual coordination of the results of separate stages of complex ecological and economic evaluation. The research was carried out in Mogilev branch Institute of radiology (Republic of Belarus).


2020 ◽  
Vol 0 (6) ◽  
pp. 24-30
Author(s):  
Olga Merzlova

One of the measures to eliminate the consequences of the Chernobyl accident was the exclusion of highly contaminated land from agricultural use. During the natural decay of radionuclides there is a decrease in the activity of 137Cs and 90Sr in the soil. The issue of land return becomes relevant. The article describes the main stages of formation of the system of criteria and indicators of ecological and economic evaluation of the expediency of land return. The first part of the article is devoted to the issue of radiological evalation.


Author(s):  
Alice Welbourn ◽  
Florence Kilonzo ◽  
T.J. Mboya ◽  
Shoba Mohamed Liban
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Author(s):  
Aleksandr Glubokovskih

The results of many years of research on the cultivation of crops in fodder crop rotation on dried peat soil are presented. A productive and agroecological assessment of crop rotation with various saturation with perennial grasses is given. The data on the reduction of peat reserves and changes in the agrochemical properties of the soil are presented.


2020 ◽  
Vol 99 (5) ◽  
pp. 271-275
Author(s):  
N.B. Guseva ◽  
◽  
S.S. Nikitin ◽  
R.O. Ignatiev ◽  
E.V. Mlynchik ◽  
...  
Keyword(s):  

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