scholarly journals Structuring of Dragonfly Communities (Insecta: Odonata) in Eastern Amazon: Effects of Environmental and Spatial Factors in Preserved and Altered Streams

Insects ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 322 ◽  
Author(s):  
Oliveira-Junior ◽  
Juen

The evaluation of the effects of environmental factors on natural communities has been one of the principal approaches in ecology; although, over the past decade, increasing importance has been given to spatial factors. In this context, we evaluated the relative importance of environmental and spatial factors for the structuring of the local odonate communities in preserved and altered streams. Adult Odonata were sampled in 98 streams in eastern Amazonia, Brazil. The physical features of each stream were evaluated and spatial variables were generated. Only environmental factors accounted for the variation in the Odonata community. The same pattern was observed in the suborder Zygoptera. For Anisoptera, environmental factors alone affect the variation in the community, considering all the environments together, and the altered areas on their own. As the two Odonata suborders presented distinct responses to environmental factors, this partitioning may contribute to an improvement in the precision of studies in biomonitoring. We thus suggest that studies would have a greater explanatory potential if additional variables are included, related to biotic interactions (e.g., competition). This will require further investigation on a finer scale of environmental variation to determine how the Odonata fauna of Amazonian streams behaves under this analytical perspective.

Fire ◽  
2020 ◽  
Vol 3 (4) ◽  
pp. 54
Author(s):  
Jelveh Tamjidi ◽  
James A. Lutz

Disentangling the relative importance of habitat filtering and dispersal limitations at local scales (<1 km2) in shaping species composition remains an important question in community ecology. Previous studies have examined the relative importance of these mechanisms using topography and selected soil properties. We examined both topography and edaphic properties from 160 locations in the recently burned 25.6 ha Yosemite Forest Dynamics Plot (YFDP) in Yosemite National Park, California, USA. In addition to eight soil chemical properties, we included phosphatases and urease enzymes in a definition of habitat niches, primarily because of their rapid changes with fire (compared to soil nutrients) and also their role in ecosystem function. We applied environmental variables to the distributions of 11 species. More species–habitat associations were defined by soil properties (54.5%) than topographically-defined habitat (45.4%). We also examined the relative importance of spatial and environmental factors in species assemblage. Proportions explained by spatial and environmental factors differed among species and demographic metrics (stem abundance, basal area increment, mortality, and recruitment). Spatial factors explained more variation than environmental factors in stem abundance, mortality, and recruitment. The contributions of urease and acid phosphatase to habitat definition were significant for species abundance and basal area increment. These results emphasize that a more complete understanding of niche parameters is needed beyond simple topographic factors to explain species habitat preference. The stronger contribution of spatial factors suggests that dispersal limitation and unmeasured environmental variables have high explanatory power for species assemblage in this coniferous forest.


Author(s):  
Dean Jacobsen ◽  
Olivier Dangles

Chapter 6 presents the interaction between space and time in determining the organization of natural communities in high altitude heterogeneous waterscapes. After explaining why high altitude waters represent suitable models for examining metacommunity organization, the chapter focuses on dispersal—a central process to allow colonization and establishment of populations in remote localities and to counter local extinctions. Community organization patterns are then described for a variety of organisms living in high altitude waters, from microbes to invertebrates to fish and birds. These patterns reveal that both environmental and spatial variables are generally involved in species assembling. Examples of studies on directional spatial processes (e.g. through wind and water flow), waterscape genetics, and temporal variability (synchrony/asynchrony) are highlighted as promising research areas to increase the current knowledge on high altitude metacommunity dynamics.


Hydrobiologia ◽  
2021 ◽  
Author(s):  
Márk Ficsór ◽  
Zoltán Csabai

AbstractThe aim of this review is to summarize the literature knowledge about how abiotic environmental factors and biotic interactions affect the sequentially overlapping longitudinal distribution of Central European species of the net-spinning freshwater caddisfly larvae of the genus Hydropsyche (Trichoptera: Hydropsychidae). In this relation, several physical and chemical parameters of water are discussed, as well as different species-specific traits, behavioural aspects and the interaction of coexisting species. Longitudinal gradients of river networks, especially annual temperature range, flow velocity and the particle size of suspended food material play a crucial role in forming the downstream succession of characteristic species, while increased levels of organic pollution, nutrients, salinity and heavy metals facilitates the presence of more tolerant ones. Several species-specific traits, such as respiration range, net-building frequency, head capsule size or optimal net-building velocity correlate with the position of a given species in the sequence. Coexistence of species with similar ecological demands in the overlapping zones of distribution is facilitated by differences in feeding and net-building habits, microhabitat preferences and staggering life cycles, but complicated at the same time by means of inter- and intraspecific territorial behaviour, such as fighting for the ownership of larval retreats or the practice of stridulation.


2017 ◽  
Vol 68 (11) ◽  
pp. 2115 ◽  
Author(s):  
Leonardo F. B. Moreira ◽  
Tainá F. Dorado-Rodrigues ◽  
Vanda L. Ferreira ◽  
Christine Strüssmann

Species composition in floodplains is often affected by different structuring factors. Although floods play a key ecological role, habitat selection in the dry periods may blur patterns of biodiversity distribution. Here, we employed a partitioning framework to investigate the contribution of turnover and nestedness to β-diversity patterns in non-arboreal amphibians from southern Pantanal ecoregion. We investigated whether components of β-diversity change by spatial and environmental factors. We sampled grasslands and dense arboreal savannas distributed in 12 sampling sites across rainy and dry seasons, and analysed species dissimilarities using quantitative data. In the savannas, both turnover and nestedness contributed similarly to β diversity. However, we found that β diversity is driven essentially by turnover, in the grasslands. In the rainy season, balanced variation in abundance was more related to altitude and factors that induce spatial patterns, whereas dissimilarities were not related to any explanatory variable during dry season. In the Pantanal ecoregion, amphibian assemblages are influenced by a variety of seasonal constraints on terrestrial movements and biotic interactions. Our findings highlighted the role of guild-specific patterns and indicated that mass effects are important mechanisms creating amphibian community structure in the Pantanal.


1979 ◽  
Vol 44 (1) ◽  
pp. 155-160 ◽  
Author(s):  
Bruce D. Smith

To determine the pattern of selective utilization of animal species by prehistoric human populations, it is first necessary to quantify the relative importance of species of animals in the diet of prehistoric human groups through analysis of archaeologically recovered faunal samples. These values are then compared with estimates of the relative availability of different species of animals in the environment. Such estimates of the relative availability of animal species in prehistoric habitat situations, usually quantified in terms of biomass, are obtained by projecting data from modern analog situations into the past. When attempting to reconstruct prehistoric biotic communities in this manner, it is important to be aware of a number of possible sources of bias and to evaluate and apply modern wildlife data according to a set of interrelated principles. Sources of bias and criteria for selecting modern wildlife analog data are discussed.


1993 ◽  
Vol 7 (2) ◽  
pp. 107-118 ◽  
Author(s):  
Deborah Kirby Forgays ◽  
Donald G. Forgays

Over the past 20 years, significantly more women have returned to the workforce after the birth of their child. Despite gains made by the second women's movement and attendant socio‐political changes, women continue to bear the major parenting responsibilities in addition to household chores. Does this additional role of workforce member result in a more highly stressed mother? This study recruited 120 mothers of infants and toddlers from a range of occupations who provided information on their adjustment to parenting as well as individual difference factors such as maternal self‐confidence, somatic complaints, and Type A behaviour. The results suggest that the level of parenting stress is not related to employment status alone. However, the factors contributing to reported parenting stress do vary by employment status. These results highlight the need to examine the interaction of personal and environmental dimensions when studying this complex area.


Author(s):  
Aly Elgayar ◽  
Salwa Mamoun Beheiry ◽  
Alaa Jabbar ◽  
Hamad Al Ansari

Purpose Over the past decade, the United Arab Emirates (UAE) introduced several green regulatory guidelines, federal decrees, and a considerable number of environmentally friendly initiatives. Hence, the purpose of this paper is to investigate the top green materials and systems used currently in the UAE construction industry as per the new laws dictate as well as see if professionals are switching over to incorporate more green materials, systems, and/or designs. Design/methodology/approach The work involved reviewing internationally popular green materials and systems for construction, developing a questionnaire based on the literature review, surveying professionals in the seven UAE emirates, and ranking the findings based on the relative importance index. Findings Findings found the top used green materials and system in the UAE’s construction industry. As well as identified that there is a communication gap between the design and implementation phases that is possibly hindering the use of more green materials and systems. Originality/value This study sets a baseline to measure the UAE’s progress over the coming years in terms of integrating more green construction materials, systems, methodologies, and trends.


2017 ◽  
Vol 41 (3) ◽  
pp. 555-583 ◽  
Author(s):  
Niels Geiger

This article is devoted to the issue of operationalizing and empirically measuring the development of behavioral economics, focusing on trends in the academic literature. The main research goal is to provide a quantitative, bibliometric assessment to answer the question of whether the relative importance of behavioral economics has increased over the past decades. After an introduction and a short summary of the history of behavioral economics, several studies are laid out and evaluated. The results generally provide a quantitative confirmation of the story of a rise of behavioral economics that can be found in the literature, and add some notable additional insights.


2016 ◽  
Author(s):  
Eleanor K. O’Brien ◽  
Megan Higgie ◽  
Alan Reynolds ◽  
Ary A. Hoffmann ◽  
Jon R. Bridle

ABSTRACTPredicting how species will respond to the rapid climatic changes predicted this century is an urgent task. Species Distribution Models (SDMs) use the current relationship between environmental variation and species’ abundances to predict the effect of future environmental change on their distributions. However, two common assumptions of SDMs are likely to be violated in many cases: (1) that the relationship of environment with abundance or fitness is constant throughout a species’ range and will remain so in future, and (2) that abiotic factors (e.g. temperature, humidity) determine species’ distributions. We test these assumptions by relating field abundance of the rainforest fruit fly Drosophila birchii to ecological change across gradients that include its low and high altitudinal limits. We then test how such ecological variation affects the fitness of 35 D. birchii families transplanted in 591 cages to sites along two altitudinal gradients, to determine whether genetic variation in fitness responses could facilitate future adaptation to environmental change. Overall, field abundance was highest at cooler, high altitude sites, and declined towards warmer, low altitude sites. By contrast, cage fitness (productivity) increased towards warmer, lower altitude sites, suggesting that biotic interactions (absent from cages) drive ecological limits at warmer margins. In addition, the relationship between environmental variation and abundance varied significantly among gradients, indicating divergence in ecological niche across the species’ range. However, there was no evidence for local adaptation within gradients, despite greater productivity of high altitude than low altitude populations when families were reared under laboratory conditions. Families also responded similarly to transplantation along gradients, providing no evidence for fitness trade-offs that would favour local adaptation. These findings highlight the importance of (1) measuring genetic variation of key traits under ecologically relevant conditions, and (2) considering the effect of biotic interactions when predicting species’ responses to environmental change.


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