Mangrove rice biodiversity valorization in Guinea Bissau. A bottom-up approach

2021 ◽  
pp. 1-11
Author(s):  
Franco Tesio ◽  
Filippo Camerini ◽  
Giovanni Maucieri ◽  
Carlo Bertini ◽  
Streng Cerise
Keyword(s):  
Abiotic Factors ◽  
Genetic Resistance ◽  
Genetic Material ◽  
Mangrove Ecosystem ◽  
Bottom Up ◽  
Guinea Bissau ◽  
Human Labor ◽  
Staple Crop ◽  
Environment Parameters ◽  
Limited Possibility

Summary Rice is the staple crop of Guinea Bissau, and its production system is based on human labor with very limited possibility of mechanization, particularly in the Mangrove ecosystem. Due to this and to the low possibilities of controlling environment parameters, such as water level and availability, the genetic resistance to extreme abiotic factors was identified as a key point for increasing yields quantity and stability. Among the ample genetic material available in the country, no purification activities were carried out in the past decades. This led to the cultivation of mixtures or ecotypes and not to uniform varieties, with consequent issue related to cultivation and milling. On 103 samples collected, only on about 50% of ecotypes, the purification was carried out as the remaining half was too much variable. The purification ended with less than 20% of material considered stable and uniform varieties. Moreover, the program adopted a bottom-up approach for collection and variety conservation to drive the program and improve the genetic material.

EVALUATION OF A GERMPLASM COLLECTION OF SOME FRUIT TREE VARIETIES CONCERNING GENETIC RESISTANCE TO ABIOTIC FACTORS

2009 ◽  
pp. 835-840 ◽  
Author(s):  
M. Neamtu ◽  
A. Barbulescu ◽  
A. Petcu ◽  
A. Ilie ◽  
M.-M. Vlad ◽  
...  
Keyword(s):  
Abiotic Factors ◽  
Genetic Resistance ◽  
Germplasm Collection ◽  
Fruit Tree

scholarly journals Long-term resource addition to a detrital food web yields a pattern of responses more complex than pervasive bottom-up control

2017 ◽  
Author(s):  
Kendra L. Lawrence ◽  
David H Wise
Keyword(s):  
Field Experiments ◽  
Abiotic Factors ◽  
Short Term ◽  
Bottom Up ◽  
Term Experiment ◽  
Two Factors ◽  
Long Term Experiment ◽  
Short Term Experiment ◽  
Univariate Analyses

Background. Theory predicts strong bottom-up control in detritus-based food webs, yet field experiments with detritus-based terrestrial systems have uncovered contradictory evidence regarding the strength and pervasiveness of bottom-up control processes. Two factors likely leading to contradictory results are experiment duration, which influences exposure to temporal variation in abiotic factors such as rainfall and affects the likelihood of detecting approach to a new equilibrium; and openness of the experimental units to immigration and migration. To investigate the contribution of these two factors, we conducted a long-term experiment with open and fenced plots in the forest that was the site of an earlier, short-term experiment (3.5 months) with open plots (Chen & Wise 1999) that produced evidence of strong bottom-up control for 14 taxonomic groupings of primary consumers of litter and fungi (microbi-detritivores) and their predators. Methods. We added artificial high-quality detritus to ten 2 x 2-m forest-floor plots at bi-weekly intervals from April through September in three consecutive years (Supplemented treatment). Ten comparable Ambient plots were controls. Half of the Supplemented and Ambient plots were enclosed by metal fencing. Results. Arthropod community structure (based upon 18 response variables) diverged over time between Supplemented and Ambient treatments, with no effect of Fencing on the multivariate response pattern. Fencing possibly influenced only ca. 20% of the subsequent univariate analyses. Multi- and univariate analyses revealed bottom-up control by fall of Year 1 of some, but not all, microbi-detritivores and predators. During the following two years the pattern of responses became more complex than that observed by Chen & Wise (1999). Some taxa showed consistent bottom-up control whereas many did not. Variation across years could not be explained completely by differences in rainfall because some taxa exhibited negative, not positive, responses to detrital supplementation. Discussion. Our 3-yr experiment did not confirm the conclusion of strong, pervasive bottom-up control of microbi-detritivores and predators reported by Chen and Wise (1999). Our longer-term experiment revealed a more complex pattern of responses, a pattern much closer to the range of outcomes reported in the literature for many short-term experiments. Much of the variation in responses across studies likely reflects variation in factors such as rainfall and the quality of added detritus. Nevertheless, it is also possible that long-term resource enhancement can drive a community towards a new equilibrium state that differs from what would have been predicted from the initial short-term responses exhibited by primary and secondary consumers.

scholarly journals Response of mycorrhizae to herbivory and soil moisture in a semiarid grazing ecosystem

2020 ◽  
Author(s):  
Yadugiri V Tiruvaimozhi ◽  
Sumanta Bagchi ◽  
Mahesh Sankaran
Keyword(s):  
Water Availability ◽  
Host Species ◽  
Abiotic Factors ◽  
Tissue Loss ◽  
Annual Precipitation ◽  
Top Down ◽  
Short Term ◽  
Bottom Up ◽  
Irrigation Treatments

AbstractArbuscular mycorrhizal fungal (AMF) symbioses with plants can be influenced by top-down forces such as grazing, and also by bottom-up forces such as soil resource availability, both of which are being altered by anthropogenic and global change drivers. While the influence of each of these factors on AMF symbioses has been widely studied, explicit tests of the relative strengths of top-down versus bottom-up influences on these ubiquitous plant root symbioses are few. We studied AMF colonization responses of four species of graminoids (3 grasses Elymus longae-aristatus, Leymus secalinus and Stipa orientalis, and a sedge Carex melanantha) common to semiarid high-altitude rangelands of the Spiti region, Trans-Himalaya, to changes in a top-down driver, grazing intensity (through short-term clipping and long-term grazer exclusion experiments), and a bottom-up driver, water availability (using irrigation treatments, and by evaluating responses to annual precipitation levels across years). Over three years, AMF colonization in all four host species was influenced by precipitation, with the highest and lowest AMF colonization levels corresponding to years with the lowest and highest rainfall, respectively. However, responses to long-term grazer exclusion differed among host species, and across years: while some species showed decreases in AMF colonization levels under grazing, others showed increases from ungrazed control levels, and these responses changed, even reversed, across years. Responses to short-term clipping and irrigation treatments also differed among hosts, with some species responding to irrigation alone, some to clipping and irrigation combined, and others showing no changes in AMF colonization from control levels in any of the treatments. In our study, long-term changes in water availability influenced AMF colonization levels, while short-term responses were host specific. Responses to above-ground tissue loss, however, differed among host species both in the long- and short-term. Overall, this study demonstrates that while AMF colonization levels correspond to annual precipitation levels in this semiarid ecosystem, host species also play a role in influencing plant-AMF interactions in these rangelands, with colonization levels and responses to abiotic factors changing with host species.

scholarly journals Selection Forces Driving Herding of Herbivorous Insect Larvae

2021 ◽  
Vol 9 ◽  
Author(s):  
Emma Despland
Keyword(s):  
Plant Defenses ◽  
Abiotic Factors ◽  
Tropical Species ◽  
Herbivorous Insect ◽  
Insect Larvae ◽  
Top Down ◽  
Warning Signals ◽  
Bottom Up ◽  
Toxic Plants ◽  
Defensive Behaviors

Herding behavior is widespread among herbivorous insect larvae across several orders. These larval societies represent one of several different forms of insect sociality that have historically received less attention than the well-known eusocial model but are showing us that social diversity in insects is broader than originally imagined. These alternative forms of sociality often focus attention on the ecology, rather than the genetics, of sociality. Indeed, mutually beneficial cooperation among individuals is increasingly recognized as important relative to relatedness in the evolution of sociality, and I will explore its role in larval insect herds. Larval herds vary in in the complexity of their social behavior but what they have in common includes exhibiting specialized social behaviors that are ineffective in isolated individuals but mutually beneficial in groups. They hence constitute cooperation with direct advantages that doesn’t require kinship between cooperators to be adaptive. Examples include: trail following, head-to-tail processions and other behaviors that keep groups together, huddling tightly to bask, synchronized biting and edge-feeding to overwhelm plant defenses, silk production for shelter building or covering plant trichomes and collective defensive behaviors like head-swaying. Various selective advantages to group living have been suggested and I propose that different benefits are at play in different taxa where herding has evolved independently. Proposed benefits include those relative to selection pressure from abiotic factors (e.g., thermoregulation), to bottom-up pressures from plants or to top-down pressures from natural enemies. The adaptive value of herding cooperation must be understood in the context of the organism’s niche and suite of traits. I propose several such suites in herbivorous larvae that occupy different niches. First, some herds aggregate to thermoregulate collectively, particularly in early spring feeders of the temperate zone. Second, other species aggregate to overwhelm host plant defenses, frequently observed in tropical species. Third, species that feed on toxic plants can aggregate to enhance the warning signal produced by aposematic coloration or stereotyped defensive behaviors. Finally, the combination of traits including gregariousness, conspicuous behavior and warning signals can be favored by a synergy between bottom-up and top-down selective forces. When larvae on toxic plants aggregate to overcome plant defenses, this grouping makes them conspicuous to predators and favors warning signals. I thus conclude that a single explanation is not sufficient for the broad range of herding behaviors that occurs in phylogenetically diverse insect larvae in different environments.

Towards a better understanding of past biotic drivers of river and floodplain geomorphology

2020 ◽  
Author(s):  
Annegret Larsen ◽  
Tony Reimann ◽  
Christoph Sperisen ◽  
Vincent Robin ◽  
Stuart N Lane
Keyword(s):  
Ecosystem Engineer ◽  
Human Impacts ◽  
Abiotic Factors ◽  
Genetic Material ◽  
Environmental Dna ◽  
Ecosystem Engineers ◽  
Transport Processes ◽  
Decadal Scale ◽  
Geomorphic Processes

<p>Geomorphology has long considered the role of abiotic factors in geomorphic processes, including tectonics, geology, climate and relief, as well as humans impact upon them. Biotic factors however, including not only plants but also bacteria and protists, biofilms, fungi, insects, invertebrates, and animals are increasingly recognized as governing geomorphic processes on many spatial and temporal scales. We argue that if fauna are important as geological agents, then understanding the complex response of geomorphic systems to fauna is necessary to understand the past, present and future of the fluvial environment. It is not surprising that studies of the Late Quaternary evolution of fluvial morphodynamics have largely focused upon changes in the sedimentary soil-sediment sequences that result from climate change; (ii) vegetation change; and/or (iii) human impacts. Reconstruction of vegetation and climate from pollen and other records facilitates these analyses. But if animals are shown to be an important influence on geomorphic processes today, then it is quite possible that they were also important historically. For example, conclusive interpretation of Holocene river changes may be limited because of an incomplete or partial account of the presence and/or absence of data on the role of ecosystem engineers in modifying the riparian and aquatic ecosystems, including hydro-geomorphic processes. DNA found within historical deposits may be used to constrain the role of past ecosystem engineers. Analysis of ancient environmental DNA up to date includes palaeo-environmental DNA from sedimentary deposits (sedaDNA) from disseminated genetic material found within sedimentary archives, including paleo-dietary ancient DNA. Here, we use an analogue study investigating the present hydro-geomorphic and biogeochemical changes that the ecosystem engineer beaver (Castor fiber) creates at four sites in central Europe to better understand and quantify the effects of beaver ecosystem engineering on a seasonal to decadal scale. We utilize these results to interpret the chrono-stratigraphy of two Holocene beaver sites, including macro-fossil and sedaDNA sampling, and test for the first time if sedaDNA can support the investigation of beaver-induced palao-environmental conditions in river floodplains. We find that sedaDNA data and other palaeo-botanical proxies complement each other showing wider diversity of species than if the methods are used separately. However, care must be taken with regards of experimental setup, and further investigation into the effects of transport processes and/or quantitative representativeness is needed.</p>

scholarly journals MAJOR DISEASES OF WHEAT AND THEIR MANAGEMENT: A REVIEW

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Raveena Chaudhary ◽  
Mamta Pujari
Keyword(s):  
Bacterial Blight ◽  
Abiotic Factors ◽  
Wheat Plant ◽  
Tan Spot ◽  
Control Measures ◽  
Common Disease ◽  
Loose Smut ◽  
Resistant Varieties ◽  
The Common ◽  
Staple Crop

Wheat is the staple crop throughout the world and a great source of nutrition. Sometimes the wheat plant gets attacked by pathogens like fungi, bacteria and virus. Some of the common disease their symptoms and management are studied. The complexity of the interaction between a pathogen and its host, influenced by biotic and abiotic factors of the environment, make the control of these disease. Fungi is the most common causative agent in case of wheat. Some of the common disease caused by fungi are leaf rust, stem rest, stripe rust, loose smut, tan spot, powdery mildew, ergot and common bunt. Virus and bacteria also cause diseases in wheat. Wheat strike mosaic virus one of the diseases is bacterial blight of leaf. These diseases can be controlled by using disease resistant varieties. Due to the infection of these diseases there can be loss of 40-50% but sometimes it may be more. These diseases can be controlled by using some control measures. There are several chemical and herbal methods are used for the control of these diseases.

scholarly journals Structural, Metabolic and Evolutionary Comparison of Bacterial Endospore and Exospore Formation

2021 ◽  
Vol 12 ◽  
Author(s):  
Polina Beskrovnaya ◽  
Danielle L. Sexton ◽  
Mona Golmohammadzadeh ◽  
Ameena Hashimi ◽  
Elitza I. Tocheva
Keyword(s):  
Morphological Changes ◽  
Abiotic Factors ◽  
Bacterial Species ◽  
Genetic Material ◽  
Evolutionary Origins ◽  
Environmental Selection ◽  
Microbial Population Dynamics ◽  
Morphological Differences ◽  
Evolutionary Comparison

Sporulation is a specialized developmental program employed by a diverse set of bacteria which culminates in the formation of dormant cells displaying increased resilience to stressors. This represents a major survival strategy for bacteria facing harsh environmental conditions, including nutrient limitation, heat, desiccation, and exposure to antimicrobial compounds. Through dispersal to new environments via biotic or abiotic factors, sporulation provides a means for disseminating genetic material and promotes encounters with preferable environments thus promoting environmental selection. Several types of bacterial sporulation have been characterized, each involving numerous morphological changes regulated and performed by non-homologous pathways. Despite their likely independent evolutionary origins, all known modes of sporulation are typically triggered by limited nutrients and require extensive membrane and peptidoglycan remodeling. While distinct modes of sporulation have been observed in diverse species, two major types are at the forefront of understanding the role of sporulation in human health, and microbial population dynamics and survival. Here, we outline endospore and exospore formation by members of the phyla Firmicutes and Actinobacteria, respectively. Using recent advances in molecular and structural biology, we point to the regulatory, genetic, and morphological differences unique to endo- and exospore formation, discuss shared characteristics that contribute to the enhanced environmental survival of spores and, finally, cover the evolutionary aspects of sporulation that contribute to bacterial species diversification.

scholarly journals Mangrove ecosystem in North Sumatran (Indonesia) forests serves as a suitable habitat for mud crabs (Scylla serrata and S. olivacea)

2021 ◽  
Vol 22 (3) ◽  
Author(s):  
RIKA KARNIATI ◽  
NURDIN SULISTIYONO ◽  
RIZKA AMELIA ◽  
BEJO SLAMET ◽  
YUNTHA BIMANTARA ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Abiotic Factors ◽  
Economic Value ◽  
Canopy Cover ◽  
Stand Density ◽  
Mangrove Ecosystem ◽  
Scylla Serrata ◽  
Suitable Habitat ◽  
Biotic Factors ◽  
Mud Crabs

Abstract. Karniati R, Sulistiyono N, Amelia R, Slamet B, Bimantara Y, Basyuni M. 2021. Mangrove ecosystem in North Sumatran (Indonesia) forests serves as a suitable habitat for mud crabs (Scylla serrata and S. olivacea). Biodiversitas 22: 1489-1496. Mud crabs (Scylla serrata and Scylla olivacea) are often found in muddy substrates associated with mangrove vegetation. The habitat of these crabs ranges from tropical estuaries to sheltered subtropical areas, riverbanks, lower river traits, and intertidal areas. These crabs have an important economic value, and it increases the income of the communities living around the mangrove area. This study aims to obtain more information on the environmental factors of habitat for mud crabs (S. serrata and S. olivacea): insights on the effects of abiotic and biotic factors and potential economic value, in the village of Lubuk Kertang, Langkat, North Sumatra, Indonesia. Data were collected by measuring abiotic factors (temperature, pH, salinity, dissolved oxygen, mud depth, distance from the river) and biotic factors (mangrove stand density through canopy cover). The dataset was analyzed using a binary logistic regression analysis with a stepwise method. Results showed that the abiotic factors that contributed to the presence of the mud crab were dissolved oxygen and a mud depth of 68.7%. Meanwhile, the remaining 31.3% that contributed to the presence of mud crabs were abiotic factors (temperature, pH, salinity, distance from rivers) and biotic factors (stand density through canopy cover). The present study suggests that dissolved oxygen and mud depth have an important function in predicting the presence of mud crabs.

Sign in / Sign up

Export Citation Format

Share Document