Community dynamics in highland watersheds

2017 ◽  
Author(s):  
Dean Jacobsen ◽  
Olivier Dangles
Keyword(s):  
High Altitude ◽  
Community Dynamics ◽  
Community Organization ◽  
Current Knowledge ◽  
Central Process ◽  
Spatial Variables ◽  
Research Areas ◽  
Local Extinctions ◽  
Metacommunity Dynamics ◽  
Natural Communities

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.

Ecology of High Altitude Waters

2017 ◽  
Author(s):  
Dean Jacobsen ◽  
Olivier Dangles
Keyword(s):  
High Altitude ◽  
Species Interactions ◽  
Community Dynamics ◽  
Human Impacts ◽  
Current Knowledge ◽  
Stress Gradient ◽  
Trophic Relations ◽  
Intimate Contact ◽  
Climate Change Effects ◽  
Patterns And Processes

This book brings together current knowledge on patterns and processes in the ecology of streams, lakes, and wetlands situated at more than 3000 m above sea level. The alpine headwaters of the large Asian rivers and Lake Titicaca are both well-known and iconic examples. High altitude waters include more than these systems—they are both numerous and cover many habitat types, organisms, and specializations. The book provides an overview of the variety of aquatic ecosystems and habitats, their environmental features, prominent species, and their functional adaptations to the harsh aquatic environmental conditions through to global diversity patterns along altitudinal gradients, community dynamics, species interactions and dispersal, trophic relations, and energy flows. High altitude waters are ideal systems to address a broad range of topical themes in ecology because patterns and processes are both diverse and singular. The book highlights how key concepts in ecology (e.g. the stress gradient hypothesis, the biodiversity–ecosystem functioning relationship) could find relevant study models in high altitude waters. The usual perception of pristine mountain waters is far from true, particularly in the case of high altitude waters at low latitudes where human population density is often high, and local communities live in intimate contact with, utilize, influence, and exploit these aquatic systems. Climate change effects, extinction risks of mountain populations due to vanishing glaciers, multiple human impacts, management, and conservation are also treated thoroughly. The book is richly illustrated with diagrams and numerous pictures of these poorly known systems and species.

scholarly journals Pulmonary Hypertension in Acute and Chronic High Altitude Maladaptation Disorders

2021 ◽  
Vol 18 (4) ◽  
pp. 1692
Author(s):  
Akylbek Sydykov ◽  
Argen Mamazhakypov ◽  
Abdirashit Maripov ◽  
Djuro Kosanovic ◽  
Norbert Weissmann ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
High Altitude ◽  
Clinical Experience ◽  
Current Knowledge ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Treatment Options ◽  
Right Heart Failure ◽  
Channel Blockers ◽  
The Right ◽  
Extensive Clinical Experience

Alveolar hypoxia is the most prominent feature of high altitude environment with well-known consequences for the cardio-pulmonary system, including development of pulmonary hypertension. Pulmonary hypertension due to an exaggerated hypoxic pulmonary vasoconstriction contributes to high altitude pulmonary edema (HAPE), a life-threatening disorder, occurring at high altitudes in non-acclimatized healthy individuals. Despite a strong physiologic rationale for using vasodilators for prevention and treatment of HAPE, no systematic studies of their efficacy have been conducted to date. Calcium-channel blockers are currently recommended for drug prophylaxis in high-risk individuals with a clear history of recurrent HAPE based on the extensive clinical experience with nifedipine in HAPE prevention in susceptible individuals. Chronic exposure to hypoxia induces pulmonary vascular remodeling and development of pulmonary hypertension, which places an increased pressure load on the right ventricle leading to right heart failure. Further, pulmonary hypertension along with excessive erythrocytosis may complicate chronic mountain sickness, another high altitude maladaptation disorder. Importantly, other causes than hypoxia may potentially underlie and/or contribute to pulmonary hypertension at high altitude, such as chronic heart and lung diseases, thrombotic or embolic diseases. Extensive clinical experience with drugs in patients with pulmonary arterial hypertension suggests their potential for treatment of high altitude pulmonary hypertension. Small studies have demonstrated their efficacy in reducing pulmonary artery pressure in high altitude residents. However, no drugs have been approved to date for the therapy of chronic high altitude pulmonary hypertension. This work provides a literature review on the role of pulmonary hypertension in the pathogenesis of acute and chronic high altitude maladaptation disorders and summarizes current knowledge regarding potential treatment options.

Convenience Sample of On-Farm Research Cooperators Representative of Wisconsin Farmers

2009 ◽  
Vol 23 (2) ◽  
pp. 300-307 ◽  
Author(s):  
Edward C. Luschei ◽  
Clarissa M. Hammond ◽  
Chris M. Boerboom ◽  
Pete J. Nowak
Keyword(s):  
Weed Management ◽  
Selection Criteria ◽  
Community Dynamics ◽  
Multivariate Analyses ◽  
Theoretical Argument ◽  
Convenience Sample ◽  
Research Areas ◽  
On Farm ◽  
Unknown Bias ◽  
Management Behaviors

Researchers interested in describing or understanding agroecological systems have many reasons to consider on-farm research. Yet, despite the inherent realism and pedagogical value of on-farm studies, recruiting cooperators can be difficult and this difficulty can result in so-called “convenience samples” containing a potentially large and unknown bias. There is often no formal justification for claiming that on-farm research results can be extrapolated to farms beyond those participating in the study. In some sufficiently well-understood research areas, models may be able to correct for potential bias; however, no theoretical argument is as persuasive as a direct comparison between a randomized and a convenience sample. In a 30-cooperator on-farm study investigating weed community dynamics across the state of Wisconsin, we distributed a written survey probing farmer weed management behaviors and attitudes. The survey contained 59 questions that overlapped a large, randomized survey of farmer corn pest management behavior. We compared 187 respondents from the larger survey with the 18 respondents from our on-farm study. For dichotomous response questions, we found no difference in response rate for 80% of the questions (α = 0.2, β > 0.5). Differences between the two groups were logically connected to the selection criteria used to recruit cooperators in the on-farm study. Similarly, comparisons of nondichotomous response questions did not differ for 80% of the questions (α = 0.05, β > 0.9). Exploratory multivariate analyses failed to reveal differences that might have been hidden from the marginal analyses. We argue that our findings support the notion that the convenience samples often associated with on-farm research may be representative of the more general class of farms, despite lack of bias protection provided by truly randomized designs.

scholarly journals Thin Air Resulting in High Pressure: Mountain Sickness and Hypoxia-Induced Pulmonary Hypertension

2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Jan Grimminger ◽  
Manuel Richter ◽  
Khodr Tello ◽  
Natascha Sommer ◽  
Henning Gall ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
High Altitude ◽  
Hypobaric Hypoxia ◽  
Current Knowledge ◽  
Treatment Options ◽  
Acute Response ◽  
Mechanisms Of Adaptation ◽  
Mountain Sickness

With rising altitude the partial pressure of oxygen falls. This phenomenon leads to hypobaric hypoxia at high altitude. Since more than 140 million people permanently live at heights above 2500 m and more than 35 million travel to these heights each year, understanding the mechanisms resulting in acute or chronic maladaptation of the human body to these circumstances is crucial. This review summarizes current knowledge of the body’s acute response to these circumstances, possible complications and their treatment, and health care issues resulting from long-term exposure to high altitude. It furthermore describes the characteristic mechanisms of adaptation to life in hypobaric hypoxia expressed by the three major ethnic groups permanently dwelling at high altitude. We additionally summarize current knowledge regarding possible treatment options for hypoxia-induced pulmonary hypertension by reviewing in vitro, rodent, and human studies in this area of research.

scholarly journals Biotic rescaling reveals importance of species interactions for variation in biodiversity responses to climate change

2020 ◽  
Vol 117 (37) ◽  
pp. 22858-22865 ◽  
Author(s):  
Vigdis Vandvik ◽  
Olav Skarpaas ◽  
Kari Klanderud ◽  
Richard J. Telford ◽  
Aud H. Halbritter ◽  
...  
Keyword(s):  
Climate Change ◽  
Species Interactions ◽  
Community Dynamics ◽  
Biotic Interactions ◽  
Plant Interactions ◽  
Climate Gradients ◽  
Climate Change Responses ◽  
Local Extinctions ◽  
Future Work ◽  
Underlying Processes

Generality in understanding biodiversity responses to climate change has been hampered by substantial variation in the rates and even directions of response to a given change in climate. We propose that such context dependencies can be clarified by rescaling climate gradients in terms of the underlying biological processes, with biotic interactions as a particularly important process. We tested this rescaling approach in a replicated field experiment where entire montane grassland communities were transplanted in the direction of expected temperature and/or precipitation change. In line with earlier work, we found considerable variation across sites in community dynamics in response to climate change. However, these complex context dependencies could be substantially reduced or eliminated by rescaling climate drivers in terms of proxies of plant−plant interactions. Specifically, bryophytes limited colonization by new species into local communities, whereas the cover of those colonists, along with bryophytes, were the primary drivers of local extinctions. These specific interactions are relatively understudied, suggesting important directions for future work in similar systems. More generally, the success of our approach in explaining and simplifying landscape-level variation in climate change responses suggests that developing and testing proxies for relevant underlying processes could be a fruitful direction for building more general models of biodiversity response to climate change.

scholarly journals Enhancing Sustainability by Improving Plant Salt Tolerance through Macro- and Micro-Algal Biostimulants

Biology ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 253 ◽  
Author(s):  
Petronia Carillo ◽  
Loredana F. Ciarmiello ◽  
Pasqualina Woodrow ◽  
Giandomenico Corrado ◽  
Pasquale Chiaiese ◽  
...  
Keyword(s):  
Salt Stress ◽  
Current Knowledge ◽  
Extraction Methods ◽  
Cultivated Plants ◽  
Crop Tolerance ◽  
Research Areas ◽  
Scientific Disciplines ◽  
Promote Plant Growth ◽  
Plant Salt Tolerance ◽  
Algal Extracts

Algal biomass, extracts, or derivatives have long been considered a valuable material to bring benefits to humans and cultivated plants. In the last decades, it became evident that algal formulations can induce multiple effects on crops (including an increase in biomass, yield, and quality), and that algal extracts contain a series of bioactive compounds and signaling molecules, in addition to mineral and organic nutrients. The need to reduce the non-renewable chemical input in agriculture has recently prompted an increase in the use of algal extracts as a plant biostimulant, also because of their ability to promote plant growth in suboptimal conditions such as saline environments is beneficial. In this article, we discuss some research areas that are critical for the implementation in agriculture of macro- and microalgae extracts as plant biostimulants. Specifically, we provide an overview of current knowledge and achievements about extraction methods, compositions, and action mechanisms of algal extracts, focusing on salt-stress tolerance. We also outline current limitations and possible research avenues. We conclude that the comparison and the integration of knowledge on the molecular and physiological response of plants to salt and to algal extracts should also guide the extraction procedures and application methods. The effects of algal biostimulants have been mainly investigated from an applied perspective, and the exploitation of different scientific disciplines is still much needed for the development of new sustainable strategies to increase crop tolerance to salt stress.

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
Keyword(s):  
Environmental Factors ◽  
Biotic Interactions ◽  
Environmental Variation ◽  
Relative Importance ◽  
Spatial Variables ◽  
Spatial Factors ◽  
The Past ◽  
Analytical Perspective ◽  
Physical Features ◽  
Natural Communities

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.

scholarly journals Keystone species and food webs

2009 ◽  
Vol 364 (1524) ◽  
pp. 1733-1741 ◽  
Author(s):  
Ferenc Jordán
Keyword(s):  
Current Knowledge ◽  
Interspecific Interactions ◽  
Keystone Species ◽  
Ecosystem Functions ◽  
General Interest ◽  
Interaction Structure ◽  
Structure And Dynamics ◽  
Rich Interaction ◽  
Natural Communities

Different species are of different importance in maintaining ecosystem functions in natural communities. Quantitative approaches are needed to identify unusually important or influential, ‘keystone’ species particularly for conservation purposes. Since the importance of some species may largely be the consequence of their rich interaction structure, one possible quantitative approach to identify the most influential species is to study their position in the network of interspecific interactions. In this paper, I discuss the role of network analysis (and centrality indices in particular) in this process and present a new and simple approach to characterizing the interaction structures of each species in a complex network. Understanding the linkage between structure and dynamics is a condition to test the results of topological studies, I briefly overview our current knowledge on this issue. The study of key nodes in networks has become an increasingly general interest in several disciplines: I will discuss some parallels. Finally, I will argue that conservation biology needs to devote more attention to identify and conserve keystone species and relatively less attention to rarity.

scholarly journals CHECKLIST OF MACRO-INVERTEBRATES OF THE SPECIAL CONSERVA-TION AREA “POGGI DI PRATA” (GROSSETO, CENTRAL ITALY)THROUGH A CITIZEN-SCIENCE AND EXPERT-BASED APPROACH

Redia ◽  
2021 ◽  
Vol 104 ◽  
pp. 63-68
Author(s):  
MATTIA MENCHETTI ◽  
FABIO CIANFERONI ◽  
GIUSEPPE MAZZA ◽  
MATTEO DAL CIN ◽  
DEBORA BARBATO ◽  
...  
Keyword(s):  
Citizen Science ◽  
Community Dynamics ◽  
Central Italy ◽  
Field Work ◽  
Land Snail ◽  
Local Conservation ◽  
Species Determination ◽  
Habitat Directive ◽  
Conservation Area ◽  
Local Extinctions

The assessment of species composition in a certain area may become outdated over time due to community dynamics including species range expansion, but also to local extinctions, species introductions and taxonomic redefinition. Therefore, updated checklists are required for animal conservation and management. Exhaustive checklists of invertebrate species may be challenging, as species determination often requires the analysis by specialists, but they are fundamental for local conservation practices. In this work, we provided an annotated preliminary checklist of invertebrates of the Special Conservation Area “Poggi di Prata” (province of Grosseto, southern Tuscany), detected through field samplings with experts, and a permanent Bioblitz set out on an online citizen-science platform (iNaturalist.org). The final dataset(1898-2020)included 329records of 282 species (217insects, 34gastropods, 30arachnids and 1 chilopod). Most records were uploaded on iNaturalist (about 56.5%), others came from observations or sampling collections(37%) and were determined by specialists. Only the remaining 6.5% of records came from published studies. Three species were protected by the Habitat Directive, 15 by the Tuscan Regional Law. We also detected two endemic or near-endemic taxa of this area: the beetle Paramaurops diecki massetanus and the land snail Marmorana saxetana. The unexpected (Italian southernmost) record of Gaurotes virginea needs to be deepened. Furthermore, 12 alien species, including insects affecting human economy and wellness (e.g., Rhinchophorous ferrugineus, Aedes albopictus, Halyomorpha halys, Dryocosmus kuriphilus and Cydalima perspectalis), were also detected. With our work, we confirmed that citizen-science platforms (e.g. iNaturalist) are valuable tools, complementary to field-work by specialists, to map local biodiversity and they may help to improve biogeographical knowledge.

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