scholarly journals The Response of Neotropical Dragonflies (Insecta: Odonata) to Local and Regional Abiotic Factors in Small Streams of the Amazon

Insects ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 446 ◽  
Author(s):  
José Max Barbosa Oliveira-Junior ◽  
Karina Dias-Silva ◽  
Maria Alexandra Teodósio ◽  
Leandro Juen
Keyword(s):  
Environmental Factors ◽  
Forest Cover ◽  
Environmental Changes ◽  
Abiotic Factors ◽  
Canopy Cover ◽  
Relative Role ◽  
Small Streams ◽  
Bioclimatic Variables ◽  
Chemical Descriptors ◽  
Physical And Chemical

Since the relative role of local and regional abiotic factors on the Odonata diversity in rainforest streams is still poorly understood, we evaluated the effects of these factors on adult Odonata (Insecta) from preserved and altered streams in the Amazonian region. Adult Odonata were sampled in 98 streams in the Eastern Amazon, Pará, Brazil. Six variables were used to measure local environmental factors: habitat integrity index; mean canopy over the channel; and four physical and chemical descriptors of the water. To measure regional environmental factors, six variables were also used: altitude gradient, three bioclimatic variables and two percentage forest variables. In partial redundancy analysis, both abiotic factors (local and regional) were important to explain the variation in the Odonata community. The Odonata community can be influenced by regional and local factors. The relationship between Odonata and the local (e.g., integrity, canopy cover, and physical and chemical descriptors of the water) and regional (e.g., bioclimatic and forest cover variables) environmental variables recorded in this study has important implications for the use of these organisms to monitor small streams of the Eastern Amazon. The scale at which habitat is measured is an important issue in community structuring studies considering the rapid environmental changes. It is of great importance to consider the different scales in studies assessing community structure, once an adequate habitat must meet the ecological needs of all stages of the life of the Odonata.

Divergent biotic and abiotic filtering of root endosphere and rhizosphere soil fungal communities along ecological gradients

2020 ◽  
Vol 96 (7) ◽  
Author(s):  
Candice Y Lumibao ◽  
Elizabeth R Kimbrough ◽  
Richard H Day ◽  
William H Conner ◽  
Ken W Krauss ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Abiotic Factors ◽  
Canopy Cover ◽  
Host Density ◽  
Fungal Communities ◽  
Biotic Factors ◽  
Wetland Ecosystems ◽  
Rhizosphere Fungi ◽  
Salinity Levels ◽  
Salinity Water

ABSTRACT Plant roots assemble in two distinct microbial compartments: the rhizosphere (microbes in soil surrounding roots) and the endosphere (microbes within roots). Our knowledge of fungal community assembly in these compartments is limited, especially in wetlands. We tested the hypothesis that biotic factors would have direct effects on rhizosphere and endosphere assembly, while abiotic factors would have direct and indirect effects. Using a field study, we examined the influences of salinity, water level and biotic factors on baldcypress (Taxodium distichum) fungal communities. We found that endosphere fungi, unlike rhizosphere fungi, were correlated with host density and canopy cover, suggesting that hosts can impose selective filters on fungi colonizing their roots. Meanwhile, local abiotic conditions strongly influenced both rhizosphere and endosphere diversity in opposite patterns, e.g. highest endosphere diversity (hump-shaped) and lowest rhizosphere diversity (U-shaped) at intermediate salinity levels. These results indicate that the assembly and structure of the root endosphere and rhizosphere within a host can be shaped by different processes. Our results also highlight the importance of assessing how environmental changes affect plant and plant-associated fungal communities in wetland ecosystems where saltwater intrusion and sea level rise are major threats to both plant and fungal communities.

Reach-scale effects of riparian forest cover on urban stream ecosystems

2005 ◽  
Vol 62 (10) ◽  
pp. 2312-2329 ◽  
Author(s):  
Allison H Roy ◽  
Christina L Faust ◽  
Mary C Freeman ◽  
Judith L Meyer
Keyword(s):  
Land Cover ◽  
Management Practices ◽  
Forest Cover ◽  
Scale Effects ◽  
Riparian Forest ◽  
Canopy Cover ◽  
Habitat Diversity ◽  
Urban Stream ◽  
Ecosystem Integrity ◽  
Small Streams

We compared habitat and biota between paired open and forested reaches within five small streams (basin area 10–20 km2) in suburban catchments (9%–49% urban land cover) in the Piedmont of Georgia, USA. Stream reaches with open canopies were narrower than forested reaches (4.1 versus 5.0 m, respectively). There were no differences in habitat diversity (variation in velocity, depth, or bed particle size) between open and forested reaches. However, absence of local forest cover corresponded to decreased large wood and increased algal chlorophyll a standing crop biomass. These differences in basal food resources translated into higher densities of fishes in open (9.0 individuals·m–2) versus forested (4.9 individuals·m–2) reaches, primarily attributed to higher densities of the herbivore Campostoma oligolepis. Densities of terrestrial invertebrate inputs were higher in open reaches; however, trends suggested higher biomass of terrestrial inputs in forested reaches and a corresponding higher density of terrestrial prey consumed by water column feeding fishes. Reach-scale biotic integrity (macroinvertebrates, salamanders, and fishes) was largely unaffected by differences in canopy cover. In urbanizing areas where catchment land cover drives habitat and biotic quality, management practices that rely exclusively on forested riparian areas for stream protection are unlikely to be effective at maintaining ecosystem integrity.

scholarly journals The Role of Recent (1985–2014) Patterns of Land Abandonment and Environmental Factors in the Establishment and Growth of Secondary Forests in the Iberian Peninsula

Land ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 817
Author(s):  
Marina Palmero-Iniesta ◽  
Josep Maria Espelta ◽  
Mario Padial-Iglesias ◽  
Òscar Gonzàlez-Guerrero ◽  
Lluís Pesquer ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Iberian Peninsula ◽  
Forest Cover ◽  
Secondary Forest ◽  
Forest Growth ◽  
Deciduous Forests ◽  
Secondary Forests ◽  
Study Region ◽  
Leaf Habit ◽  
Forest Establishment

Farmland abandonment has been a widespread land-use change in the Iberian Peninsula since the second half of the 20th century, leading to the establishment of secondary forests across the region. In this study, we aimed to address changes in the recent (1985–2014) emergence patterns of these forests and examine how environmental factors affected their growth by considering differences in leaf-habit types. We used a combination of Landsat-derived land-cover maps and aboveground biomass (AGB) maps from the European Space Agency to assess the secondary forest establishment and growth, respectively, in the study region. We also obtained a set of topographic, climatic and landscape variables from diverse GIS layers and used them for determining changes over time in the environmental drivers of forest establishment and AGB using general linear models. The results highlight that secondary forest cover was still increasing in the Iberian Peninsula at a rate above the European average. Yet, they also indicate a directional change in the emergence of secondary forests towards lower and less steep regions with higher water availability (mean rainfall and SPEI) and less forest cover but are subjected to greater drought events. In addition, these environmental factors differentially affect the growth of forests with different leaf-habit types: i.e., needleleaf secondary forests being less favoured by high temperature and precipitation, and broadleaf deciduous forests being most negatively affected by drought. Finally, these spatial patterns of forest emergence and the contrasting responses of forest leaf-habits to environmental factors explained the major development of broadleaf evergreen compared to broadleaf deciduous forests and, especially, needleleaf secondary forests. These results will improve the knowledge of forest dynamics that have occurred in the Iberian Peninsula in recent decades and provide an essential tool for understanding the potential effects of climate warming on secondary forest growth.

scholarly journals Effect of Environmental Factors on the Germination and Emergence of Drunken Horse Grass (Achnatherum inebrians)

Weed Science ◽  
2020 ◽  
pp. 1-29
Author(s):  
Yonghuan Yue ◽  
Guili Jin ◽  
Weihua Lu ◽  
Ke Gong ◽  
Wanqiang Han ◽  
...  
Keyword(s):  
Seed Germination ◽  
Environmental Factors ◽  
Abiotic Factors ◽  
Seedling Emergence ◽  
Management Strategies ◽  
Germination Percentage ◽  
Western China ◽  
Burial Depth ◽  
Achnatherum Inebrians ◽  
Water Ph

Abstract Drunken horse grass [Achnatherum inebrians (Hance) Keng] is a perennial poisonous weed in western China. A comprehensive understanding of the ecological response of A. inebrians germination to environmental factors would facilitate the formulation of better management strategies for this weed. Experiments were conducted under laboratory conditions to assess the effects of various abiotic factors, including temperature, light, water, pH and burial depth, on the seed germination and seedling emergence of A. inebrians. The seeds germinated at constant temperatures of 15, 20, 25, 30, 35°C and in alternating-temperature regimes of 15/5, 20/10, 25/15, 30/20, 35/25, 40/30°C, and the seed germination percentages under constant and alternating temperatures ranged from 51% to 94% and 15% to 93%, respectively. Maximum germination occurred at a constant temperature of 25°C, and germination was prevented at 45/35°C. Light did not appear to affect seed germination. The germination percentage of seeds was more than 75% in the pH range of 5 to 10, with the highest germination percentage at pH 6. The seeds germinated at osmotic potentials of 0 MPa to -1.0 MPa, but decreasing osmotic potential inhibited germination, with no germination at -1.2MPa. After 21 d of low osmotic stress, the seeds that did not germinate after rehydration had not lost their vitality. The seedling emergence percentage was highest (90%) when seeds were buried at 1 cm but declined with increasing burial depth and no emergence at 9 cm. Deep tillage may be effective in limiting the seed germination and emergence of this species. The results of this study provide useful information on the conditions necessary for A. inebrians germination and provide a theoretical basis for science-based prediction, prevention and control of this species.

scholarly journals Longitudinal sampling of external mucosae in farmed European seabass reveals the impact of water temperature on bacterial dynamics

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Daniela Rosado ◽  
Raquel Xavier ◽  
Jo Cable ◽  
Ricardo Severino ◽  
Pedro Tarroso ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Microbial Diversity ◽  
Water Temperature ◽  
Abiotic Factors ◽  
Seasonal Effect ◽  
Microbial Composition ◽  
Surrounding Water ◽  
European Seabass ◽  
And Function ◽  
The Impact

AbstractFish microbiota are intrinsically linked to health and fitness, but they are highly variable and influenced by both biotic and abiotic factors. Water temperature particularly limits bacterial adhesion and growth, impacting microbial diversity and bacterial infections on the skin and gills. Aquaculture is heavily affected by infectious diseases, especially in warmer months, and industry practices often promote stress and microbial dysbiosis, leading to an increased abundance of potentially pathogenic bacteria. In this regard, fish mucosa health is extremely important because it provides a primary barrier against pathogens. We used 16 rRNA V4 metataxonomics to characterize the skin and gill microbiota of the European seabass, Dicentrarchus labrax, and the surrounding water over 12 months, assessing the impact of water temperature on microbial diversity and function. We show that the microbiota of external mucosae are highly dynamic with consistent longitudinal trends in taxon diversity. Several potentially pathogenic genera (Aliivibrio, Photobacterium, Pseudomonas, and Vibrio) were highly abundant, showing complex interactions with other bacterial genera, some of which with recognized probiotic activity, and were also significantly impacted by changes in temperature. The surrounding water temperature influenced fish microbial composition, structure and function over time (days and months). Additionally, dysbiosis was more frequent in warmer months and during transitions between cold/warm months. We also detected a strong seasonal effect in the fish microbiota, which is likely to result from the compound action of several unmeasured environmental factors (e.g., pH, nutrient availability) beyond temperature. Our results highlight the importance of performing longitudinal studies to assess the impact of environmental factors on fish microbiotas.

Environmental evolution and anthropogenic forcing in the Garigliano coastal plain (Italy) during the Holocene

The Holocene ◽  
2021 ◽  
pp. 095968362110032
Author(s):  
Halinka Di Lorenzo ◽  
Pietro Aucelli ◽  
Giuseppe Corrado ◽  
Mario De Iorio ◽  
Marcello Schiattarella ◽  
...  
Keyword(s):  
Human Activity ◽  
Coastal Plain ◽  
Forest Cover ◽  
Environmental Changes ◽  
Pollen Data ◽  
Human Environment ◽  
The Holocene ◽  
Natural Processes ◽  
History Of ◽  
The Rich

The Garigliano alluvial-coastal plain, at the Latium-Campania border (Italy), witnessed a long-lasting history of human-environment interactions, as demonstrated by the rich archaeological knowledge. With the aim of reconstructing the evolution of the landscape and its interaction with human activity during the last millennia, new pollen results from the coastal sector of the Garigliano Plain were compared with the available pollen data from other nearby sites. The use of pollen data from both the coastal and marine environment allowed integrating the local vegetation dynamics within a wider regional context spanning the last 8000 years. The new pollen data presented in this study derive from the analysis of a core, drilled in the coastal sector, which intercepted the lagoon-marshy environments that occurred in the plain as a response to the Holocene transgression and subsequent coastal progradation. Three radiocarbon ages indicate that the chronology of the analyzed core interval ranges from c. 7200 to c. 2000 cal yr BP. The whole data indicate that a dense forest cover characterized the landscape all along the Prehistoric period, when a few signs of human activity are recorded in the spectra, such as cereal crops, pasture activity and fires. The main environmental changes, forced by natural processes (coastal progradation) but probably enhanced by reclamation works, started from the Graeco-Roman period and led to the reduction of swampy areas that favoured the colonisation of the outer plain.

scholarly journals Distribution Patterns of Odonate Assemblages in Relation to Environmental Variables in Streams of South Korea

Insects ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 152 ◽  
Author(s):  
Da-Yeong Lee ◽  
Dae-Seong Lee ◽  
Mi-Jung Bae ◽  
Soon-Jin Hwang ◽  
Seong-Yu Noh ◽  
...  
Keyword(s):  
Land Use ◽  
Ecosystem Services ◽  
Environmental Factors ◽  
South Korea ◽  
Habitat Heterogeneity ◽  
Environmental Variables ◽  
Environmental Changes ◽  
Distribution Patterns ◽  
Self Organizing Map ◽  
Factors Affecting

Odonata species are sensitive to environmental changes, particularly those caused by humans, and provide valuable ecosystem services as intermediate predators in food webs. We aimed: (i) to investigate the distribution patterns of Odonata in streams on a nationwide scale across South Korea; (ii) to evaluate the relationships between the distribution patterns of odonates and their environmental conditions; and (iii) to identify indicator species and the most significant environmental factors affecting their distributions. Samples were collected from 965 sampling sites in streams across South Korea. We also measured 34 environmental variables grouped into six categories: geography, meteorology, land use, substrate composition, hydrology, and physicochemistry. A total of 83 taxa belonging to 10 families of Odonata were recorded in the dataset. Among them, eight species displayed high abundances and incidences. Self-organizing map (SOM) classified sampling sites into seven clusters (A–G) which could be divided into two distinct groups (A–C and D–G) according to the similarities of their odonate assemblages. Clusters A–C were characterized by members of the suborder Anisoptera, whereas clusters D–G were characterized by the suborder Zygoptera. Non-metric multidimensional scaling (NMDS) identified forest (%), altitude, and cobble (%) in substrata as the most influential environmental factors determining odonate assemblage compositions. Our results emphasize the importance of habitat heterogeneity by demonstrating its effect on odonate assemblages.

scholarly journals Gold, timber, war and parks : A history of the Rushworth Forest in central Victoria

2010 ◽  
Vol 122 (2) ◽  
pp. 130 ◽  
Author(s):  
Ruth E. Lawrence ◽  
Marc P. Bellette
Keyword(s):  
World War Ii ◽  
Gold Mining ◽  
Forest Cover ◽  
Environmental Changes ◽  
Resource Utilisation ◽  
World War ◽  
Mining Operations ◽  
Prisoner Of War ◽  
Central Victoria ◽  
History Of

The Rushworth Forest is a Box and Ironbark open sclerophyll forest in central Victoria that has been subject to a long history of gold mining activity and forest utilisation. This paper documents the major periods of land use history in the Rushworth Forest and comments on the environmental changes that have occurred as a result. During the 1850s to 1890s, the Forest was subject to extensive gold mining operations, timber resource use, and other forest product utilisation, which generated major changes to the forest soils, vegetation structure and species cover. From the 1890s to 1930s, concern for diminishing forest cover across central Victoria led to the creation of timber reserves, including the Rushworth State Forest. After the formation of a government forestry department in 1919, silvicultural practices were introduced which aimed at maximising the output of tall timber production above all else. During World War II, the management of the Forest was taken over by the Australian Army as Prisoner of War camps were established to harvest timber from the Forest for firewood production. Following the War, the focus of forestry in Victoria moved away from the Box and Ironbark forests, but low value resource utilisation continued in the Rushworth Forest from the 1940s to 1990s. In 2002, about one-third of the Forest was declared a National Park and the other two-thirds continued as a State Forest. Today, the characteristics of the biophysical environment reflect the multiple layers of past land uses that have occurred in the Rushworth Forest.

scholarly journals Effect of land-use types on the ecomorphological structure of fish assemblage in distinct mesohabitats of neotropical streams

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Leonardo Antunes Pessoa ◽  
Matheus Tenório Baumgartner ◽  
Marcelo Percilio Santana Junior ◽  
João Paulo Alves Pagotto ◽  
Luiz Gustavo Antunes Pessoa ◽  
...  
Keyword(s):  
Land Use ◽  
Urban Environment ◽  
Fish Species ◽  
Fish Assemblage ◽  
Environmental Variables ◽  
Environmental Changes ◽  
Canopy Cover ◽  
Distinct Species ◽  
Urban Streams ◽  
Land Use Types

Abstract The use and occupation of land by human population substantially influence environmental variables and fish assemblage in streams. However, there is little knowledge on how these changes affect the ecomorphological structure of fish assemblage in mesohabitats. Therefore, we aim to assess whether the land-use types affect the ecomorphological structure of fish assemblage in distinct mesohabitats. Environmental and ichthyofaunistic data were collected in three mesohabitats (rifles, runs, and pools) of five rural and five urban streams. Twenty-one ecomorphological indices were obtained from the mean of linear morphological measurements and areas of the fishes. Subsequently, the Euclidean distance was calculated, based on the ecomorphological indices, between each pair of species, to measure the ecomorphological distances for the mesohabitats of the rural and urban streams. The results show that the urban environment is more harmful to streams than the rural one, due to changes in the environmental variables and decrease in species richness. The main environmental changes found in urban streams were the decrease in canopy cover by riparian vegetation and dissolved oxygen, and the increase in electrical conductivity and bed silting. Also, there was a significant decrease in the morphological similarity between fish species in the mesohabitats of urban streams compared to rural ones. Therefore, we can conclude that the urban environment leads to the loss of morphologically similar fish species in the mesohabitats, with only a few functionally distinct species remaining.

scholarly journals Methods of Landscape Valorization and Possibilities of Its Application in Hunting Area Categorisation

2020 ◽  
Author(s):  
Szewczyk Grzegorz ◽  
Krzysztof Lipka ◽  
Piotr Wężyk ◽  
Karolina Zięba-Kulawik ◽  
Monika Winczek
Keyword(s):  
Natural Environment ◽  
Functional Role ◽  
Large Scale ◽  
Forest Cover ◽  
Agricultural Landscape ◽  
Environmental Changes ◽  
Environmental Values ◽  
Small Game ◽  
Forest Habitats

As a result of environmental changes, assessment indexes for the agricultural landscape have been changing dramatically. Being at the interface of human activity and the natural environment, hunting is particularly sensitive to environmental changes, such as increasing deforestation or large-scale farming. The classical categorisation of hunting grounds takes into account the area, forest cover, number of forest complexes, fertility of forest habitats, lack of continuity of areas potentially favourable to wild animals. Landscape assessment methods used in architecture often better reflect the actual breeding and hunting value of a given area, especially in relation to fields and forests. The forest-field mosaic, large spatial fragmentation as well as interweaving of natural environment elements with buildings do not have to be the factors that limit the numbers of small game. Identification of the constituents of architectural-landscape interiors: content and significance assessment, determination of the functional role or assessment based on the general environmental values being represented take into account factors important for the existence of game, in particular small game.

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