degree of fragmentation
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2022 ◽  
Author(s):  
Fabrizio Marra ◽  
Alberto Frepoli ◽  
Dario Gioia ◽  
Marcello Schiattarella ◽  
Andrea Tertulliani ◽  
...  

Abstract. Rome has the world’s longest historical record of felt earthquakes, with more than 100 events during the last 2,600 years. However, no destructive earthquake has been reported in the sources and all of the greatest damage suffered in the past has been attributed to far-field events. While this fact suggests that a moderate seismotectonic regime characterizes the Rome area, no study has provided a comprehensive explanation for the lack of strong earthquakes in the region. Through the analysis of the focal mechanism and the morphostructural setting of the epicentral area of a "typical" moderate earthquake (ML = 3.3) that recently occurred in the northern urban area of Rome, we demonstrate that this event reactivated a buried segment of an ancient fault generated under both a different and a stronger tectonic regime than that which is presently active. We also show that the evident structural control over the drainage network in this area reflects an extreme degree of fragmentation of a set of buried faults generated under two competing stress fields throughout the Pleistocene. Small faults and a present-day weaker tectonic regime with respect to that acting during the Pleistocene explain the lack of strong seismicity and imply that a large earthquake could not reasonably occur.


Forests ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 25
Author(s):  
Emmanuel Da Da Ponte ◽  
Monserrat García-Calabrese ◽  
Jennifer Kriese ◽  
Nestor Cabral ◽  
Lidia Perez de Perez de Molas ◽  
...  

Over the past 40 years, Paraguay has lost the majority of its natural forest cover, thus becoming one of the countries with the highest deforestation rates in the world. The rapid expansion of the agricultural frontier, cattle ranching, and illegal logging between 1987 and 2012 resulted in the loss of 27% of original forest cover, equivalent to almost 44,000 km2. Within this context, the present research provides the first yearly analysis of forest cover change in the Paraguayan Chaco between the years 1987 and 2020. Remote sensing data obtained from Landsat images were applied to derive annual forest cover masks and deforestation rates over 34 years. Part of this study is a comprehensive assessment of the effectiveness of protected areas, as well as an analysis of the degree of fragmentation of the forest. All classification results obtained accuracies above 80% and revealed a total forest cover loss of approximately 64,700 km2. Forest clearing within protected areas was not frequent; however, some natural reserves presented losses of up to 25% of their forest cover. Through the consideration of several landscape metrics, this study reveals an onward fragmentation of forest cover, which endangers the natural habitat of numerous species.


Land ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1242
Author(s):  
Haozhe Zhang ◽  
Qingyuan Yang ◽  
Huiming Zhang ◽  
Lulu Zhou ◽  
Hongji Chen

Promoting the preservation and appreciation of ecosystem services is an important value guide for land use optimization. In this research, Fengdu County in the Three Gorges Reservoir Area was selected as the focus of a case study. From the perspective of the source and sink landscape of ecosystem services, a MOP model and FLUS model were used to optimize the areas of various land use types and the spatial configurations of those land use types in the study area in 2035 under a strict ecological constraint (SEC) scenario, a moderate ecological constraint (MEC) scenario, and a relaxed ecological constraint (REC) scenario. We also superimposed and adjusted the results of land use optimization under the three ecological constraint scenarios, and obtained land use regionalization results that integrated multiple scenarios. The results indicated that (1) there were large differences in the areas and spatial distributions of the source and sink landscapes under the three scenarios. Under the SEC scenario, the important source landscapes (ISLs), common source landscapes (CSLs), and sink landscapes (SLs) areas covered 1676.62 km2, 1190.43 km2, and 33.81 km2, respectively. A large area of the CSLs and a small area of the SLs were transformed into ISLs area, and the degree of fragmentation of the landscape was low. Under the MEC scenario, the ISLs, CSLs, and SLs areas covered 1609.22 km2, 1241.60 km2, and 49.74 km2, respectively. The development of the source landscapes and sink landscapes was similar, and the degree of fragmentation was moderate. Under the REC scenario, the ISLs, CSLs, and SLs areas covered 1603.96 km2, 1243.32 km2, and 53.58 km2, respectively. A large area of CSLs was transformed into SLs area, and the degree of fragmentation was high. (2) Fengdu County was divided into seven types of areas: ecological conservation area; agricultural production area; construction optimization area; construction-ecological area; ecological-agricultural area; agricultural-construction area; and integrated development area. The results of this study can provide references for the territorial spatial planning and management of ecological barrier zones.


Author(s):  
Stephany Diolino Cunha ◽  
Bruna Sampaio Crivilin ◽  
Matheus da Silva Araújo ◽  
Luís Antônio Coimbra Borges

Forest fragmentation is defined as the process by which a continuous area of habitat is reduced in size and divided between spaces. Therefore, due to the increase in these areas, this study aimed to conduct a systematic review of the literature on forest fragments in the Atlantic Forest biome in order to verify their main characteristics and landscape ecology. Publications in search platforms referring to the period from 2000 to 2020 were analyzed such as: SciELO, Google academic and CAPES journals portal. The search terms entered were: “Studies of forest fragments in the Atlantic Forest biome” and “Landscape ecology in forest fragments”. A total of 15 articles were selected from among the works found, and 5 of these were chosen to be evaluated in the present study. Four of the five works were carried out in the state of Espírito Santo, close to basins and sub-basins, and only one work was carried out in a state park. Thus, the evaluated works with the theme, study of fragmentation and ecology of the landscape showed a high degree of fragmentation, meaning that they have fragments smaller than 5 hectares; in addition, all fragments have an irregular edge effect. Therefore, measures aimed at the conservation of biodiversity are needed in all places so that there is ecological restoration of the landscape and conservation of fauna and flora in the Atlantic Forest biome. 


Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4542
Author(s):  
Ali Abu Almaaty ◽  
Hadeer Rashed ◽  
Maha Soliman ◽  
Eman Fayad ◽  
Fayez Althobaiti ◽  
...  

The active ingredients allicin and curcumin have a wide range of actions against fungi, bacteria, and helminths. Therefore, the study was aimed to evaluate the efficacy of allicin (AL) and curcumin (CU) as antischistosomal drugs and their biochemical effects in normal and Schistosoma mansoni-infected mice. Praziquantel (PZQ) was administrated for two successive days while AL or CU was given for two weeks from the week 7th postinfection (PI). The possible effect of different regimens on Schistosoma worms was evaluated by measuring the percentage of the recovered worms, tissue egg load, and oogram pattern. Serum alanine transaminase activity and levels of triglycerides, cholesterol, and uric acid were measured. Liver tissue malondialdehyde and reduced glutathione levels besides, the activities of glutathione-S-transferase, superoxide dismutase and catalase were assessed for the oxidative/antioxidant condition. DNA electrophoresis of liver tissue was used to indicate the degree of fragmentation. There was a significant reduction in the recovered worms and egg load, with a marked change of oogram pattern in all treated groups with PZQ, AL, and CU in comparison with infected-untreated mice. PZQ, AL, and CU prevented most of the hematological and biochemical disorders, as well as significantly improved the antioxidant capacity and enhanced DNA fragmentation in the liver tissue of schistosomiasis mice compared to the infected-untreated group. These promising results suggest that AL and CU are efficient as antischistosomal drugs, and it would be beneficial to test their combination to understand the mechanism of action and the proper period of treatment leading to the best result.


2021 ◽  
Vol 22 (8) ◽  
Author(s):  
Yeni Ratnaningrum ◽  
Sapto Indrioko ◽  
Amellita Karrin ◽  
Aditya Kurniawan ◽  
ANGGI D.C. PUTRI

Abstract. Ratnaningrum YWN, Indrioko S, Karrin A, Kurniawan A, Putri ADC. 2021. The genetic diversity and reproductive dynamics of sandalwood in Gunung Sewu (Java, Indonesia) in 2012-2019: designing conservation strategies in a continuous versus fragmented landrace. Biodiversitas 22: 3219-3229. This research aimed to compare the dynamics of the genetic diversity, mating systems, and reproductive outputs of the most fragmented (Bejiharjo) and continuous (Bleberan) sandalwood landraces in Gunung Sewu in the flowering periods of 2012-2019. Among the different sandalwood landraces found in Gunung Sewu, Bejiharjo has the highest levels of santalol; unfortunately, this landrace also requires the most attention because of heavy habitat fragmentation resulting from overexploitation, urbanization, and cave-tourism activities. Compared with Bejiharjo, Bleberan demonstrated a wider genetic base and greater outcrossing. Mature and flowering individuals in Bejiharjo decreased from 2012 to 2019 as fragmentation increased, particularly in 2019, during which extreme individual reduction due to illegal logging and land conversion was noted. Recent years consisted of more-clonalized stands, as indicated by the finding of fewer distinct genotypes and higher clonality rates. Increases in clonality and narrowing of the genetic base over time increased selfing rates and reduced offspring heterozygosity and seedling recruitment. The dynamics of genetic diversity in Bleberan, which was relatively undisturbed, appeared to be highly affected by fluctuations in the number of parental genetic bases (i.e., flowering parents) in each flowering season. Some parents bore flowers in one flowering season but remained in a vegetative state in the following season. This irregularity of flowering individuals caused fluctuations in actual population size, resulting in a different genetic base, mating system, and reproductive outputs in every season. All six loci (i.e., Dia-1, Dia-2, Est-1, Est-2, Est-3, and Skd-1) examined in Bleberan are polymorphic sites, and no missing alleles were noted in any of the observation years. Est-2 was monomorphic in Bejiharjo, where rare and missing alleles were more apparent, particularly at the seedling level. Genetic differentiation over time was observed between Bejiharjo and Bleberan, and increased fragmentation was noted in Bejiharjo. The migration rate between these two landraces also decreased over time. Focusing on maintaining the reproductive and genetic processes of each population by implementing different strategies based on the genetic base, mating systems, and degree of fragmentation and clonality of the landrace is recommended.


2021 ◽  
Vol 9 (3) ◽  
pp. 665-672
Author(s):  
Øystein T. Haug ◽  
Matthias Rosenau ◽  
Michael Rudolf ◽  
Karen Leever ◽  
Onno Oncken

Abstract. Rock avalanches produce exceptionally long run-outs that correlate with their rock volume. This relationship has been attributed to the size-dependent dynamic lowering of the effective basal friction. However, it has also been observed that run-outs of rock avalanches with similar volumes can span several orders of magnitude, suggesting additional controlling factors. Here, we analyse analogue models of rock avalanches, with the experiments designed to test the role of dynamic fragmentation. We show that for a fixed low basal friction, the run-out of experimental rock avalanches varies over 2 orders of magnitude and is determined by their degree of fragmentation, while the basal friction acts only as an upper limit on run-out. We interpret the run-out's dependence on fragmentation as being controlled by the competition between mobility enhancing spreading and energy-consuming fragmentation limited by basal friction. We formalize this competition into a scaling law based on energy conservation, which shows that the variation in the degree of fragmentation can contribute to the large variation in run-out of rock avalanches seen in nature.


Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Zhang Min ◽  
Wang Xuejie ◽  
Liu Yun

Considering that the development of urbanization cannot be separated from the application of landscape pattern evolution, in order to improve the development level of ecocity, a modeling analysis of ecological urban landscape pattern evolution based on multisource remote sensing data is proposed. Taking ecotype city as the research object, the remote sensing images of ecological urban landscape pattern are screened by using multisource remote sensing data and nonremote sensing data as the basic data. CA-Markov model is constructed and the evolution of ecological urban landscape pattern is analyzed. The experimental results show that, from 2005 to 2020, the development level of urbanization process is higher and higher and the area of building land patches is increasing, which reduces the fragmentation of building land patches. However, the landscape of cultivated land and green space is less and less, and the distribution of the patches also causes uneven phenomenon, which leads to the gradual decline of ecological urban landscape diversity. In the ecological urban landscape pattern, the degree of fragmentation and diversity of urban landscape is reduced due to the high connection and coverage of the construction land.


2021 ◽  
Vol 13 (10) ◽  
pp. 1986
Author(s):  
Junyao Zhang ◽  
Xiaomei Yang ◽  
Zhihua Wang ◽  
Tao Zhang ◽  
Xiaoliang Liu

As a developing country, China’s mangrove landscape pattern has undergone significant temporal and spatial changes over the last four decades. However, we know little about the changes in the mangrove landscape pattern characteristics other than the area at the national scale. The analysis of mangrove landscape pattern changes from different perspectives on a national scale can provide scientific support for mangrove protection and restoration. In this study, the temporal and spatial changes in the pattern of the mangrove landscape over the last 40 years in China were analyzed based on remote sensing data with high classification accuracy (99.3% of 2018). First, according to the natural geographical conditions of the coastal zone and the distribution of the mangroves, the distribution area of the mangroves in China was divided into 31 natural shores. Then, by selecting representative landscape indexes and constructing an integrated landscape index, the spatial-temporal changes in the landscape pattern of China’s mangroves over the last 40 years were analyzed based on five perspectives: Total area change, shape complexity, connectivity, fragmentation, and the integrated state of the landscape. From a temporal viewpoint, before 2000, the total area of each shore exhibited a downward trend, and the degree of connectivity deteriorated continuously, but the degree of fragmentation was stable at a low level. After 2000, although the total area improved, the degree of fragmentation gradually increased. The spatial changes are mainly reflected by the fact that the shores in Guangdong and Hainan exhibited significant differences within the same province. Based on the above analysis, corresponding scientific suggestions are proposed from temporal and spatial viewpoints to provide guidance for mangrove management and protection in China and to provide a reference for mangrove research in other regions of the world.


Universe ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 82
Author(s):  
Maurizio Pajola ◽  
Alice Lucchetti ◽  
Lara Senter ◽  
Gabriele Cremonese

We study the size frequency distribution of the blocks located in the deeply fractured, geologically active Enceladus South Polar Terrain with the aim to suggest their formative mechanisms. Through the Cassini ISS images, we identify ~17,000 blocks with sizes ranging from ~25 m to 366 m, and located at different distances from the Damascus, Baghdad and Cairo Sulci. On all counts and for both Damascus and Baghdad cases, the power-law fitting curve has an index that is similar to the one obtained on the deeply fractured, actively sublimating Hathor cliff on comet 67P/Churyumov-Gerasimenko, where several non-dislodged blocks are observed. This suggests that as for 67P, sublimation and surface stresses favor similar fractures development in the Enceladus icy matrix, hence resulting in comparable block disaggregation. A steeper power-law index for Cairo counts may suggest a higher degree of fragmentation, which could be the result of localized, stronger tectonic disruption of lithospheric ice. Eventually, we show that the smallest blocks identified are located from tens of m to 20–25 km from the Sulci fissures, while the largest blocks are found closer to the tiger stripes. This result supports the ejection hypothesis mechanism as the possible source of blocks.


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