Introductory Overview

2003 ◽  
Author(s):  
Raymond C. Smith ◽  
Douglas G. Goodin
Keyword(s):  
Ecosystem Function ◽  
Environmental Changes ◽  
Extreme Environment ◽  
Climatic Conditions ◽  
Large Lake ◽  
Proxy Records ◽  
Grassland Ecosystems ◽  
Biological Responses ◽  
Long Term Ecological Research ◽  
Dry Valley

Elias argues (chapter 18, p. 370) that ecosystems are shaped by environmental changes that have occurred over thousands of years so that the century to millennial timescale is of particular significance because “it is on these timescales that ecosystems form, break apart, and reform in new configurations.” Within this context, the authors for the three chapters in part IV evaluate evidence for climate variability since the Last Glacial Maximum (LGM) to the present. They evaluate the biological responses to these longer term changes and highlight the importance of past climatic conditions on current ecosystem function. If we view, as Elias does, glacial climate as a filter through which ecosystems have passed, then variability since the LGM comprises a significant fraction of the biotic history that shaped current ecosystems. This is an overriding theme for this section. Fountain and Lyons (chapter 16), examining a dry valley ecosystem in Antarctica (MCM), evaluate various proxy records to establish the historic context of their landscape. They argue that this historical context is important for a full understanding of ecosystems and that it is especially important for the MCM ecosystem. Providing an excellent example of legacy, the effect of past imprints on current ecosystem function, they present evidence that past climatic variations truly dictate current ecosystem status. During the LGM, ice blocked the current Taylor Valley, forming a lake that contained phytoplankton and algal mats. Subsequent warming eliminated the blockage, drained the large lake, forming several smaller ones, and established the current landscape. The former large lake supplied nutrients to the soil and current lakes. Fountain and Lyons (p. 334) state that “the vital importance of climatic legacy in the dry valleys is due to its extreme environment, low biodiversity, and short food chains.” They also observe a “polar amplification,” whereby the sharp solid/liquid phase transition of water allows small changes in climate to produce relatively large variations in ecosystem response. The Jornada Long-Term Ecological Research site (JRN) is representative of the desert shrubland and desert grassland ecosystems of the southwestern United States. Monger (chapter 17) makes use of a range of biotic (packrat middens, fossil pollen), abiotic (chronological data on lake levels, position of alpine glaciers and rock glaciers) and soil-geomorphic evidence to create a working hypothesis of the bioclimatic changes during the last 20,000 years. There is a remarkable consistency in these proxy estimates given their diversity.

Hypoxia-induced alteration of RNA modifications in the mouse testis and sperm

2021 ◽  
Author(s):  
Tong He ◽  
Huanping Guo ◽  
Xipeng Shen ◽  
Xiao Wu ◽  
Lin Xia ◽  
...  
Keyword(s):  
Hypobaric Hypoxia ◽  
Environmental Changes ◽  
Epigenetic Inheritance ◽  
Transcriptional Regulators ◽  
Extreme Environment ◽  
Mouse Testis ◽  
Rna Modification ◽  
Rna Modifications ◽  
Sperm Counts ◽  
Health Studies

Abstract Hypobaric hypoxia as an extreme environment in a plateau may have deleterious effects on human health. Studies have indicated that rush entry into a plateau may reduce male fertility and manifest in decreased sperm counts and weakened sperm motility. RNA modifications are sensitive to environmental changes and have recently emerged as novel post-transcriptional regulators in male spermatogenesis and intergenerational epigenetic inheritance. In the present study, we generated a mouse hypoxia model simulating the environment of 5500 meters in altitude for 35 days, which led to compromised spermatogenesis, decreased sperm counts, and an increased sperm deformation rate. Using this hypoxia model, we further applied our recently developed high-throughput RNA modification quantification platform based on LC–MS/MS, which exhibited the capacity to simultaneously examine 25 types of RNA modifications. Our results revealed an altered sperm RNA modifications signature in the testis (6 types) and mature sperm (11 types) under the hypoxia model, with 4 types showing overlap (Am, Gm, m7G, and m22G). Our data first drew the signature of RNA modification profiles and comprehensively analyzed the alteration of RNA modification levels in mouse testis and sperm under a mouse hypoxia model. These data may be highly related to human conditions under a similar hypoxia environment.

scholarly journals Eastern Andean environmental and climate synthesis for the last 2000 years BP from terrestrial pollen and charcoal records of Patagonia

2015 ◽  
Vol 11 (3) ◽  
pp. 2121-2157 ◽  
Author(s):  
G. D. Sottile ◽  
M. E. Echeverria ◽  
M. V. Mancini ◽  
M. M. Bianchi ◽  
M. A. Marcos ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Environmental Changes ◽  
Fire Regime ◽  
Ice Age ◽  
Circulation System ◽  
Forest Steppe ◽  
Proxy Records ◽  
The Andes ◽  
Precipitation Regimes ◽  
Southern Patagonia

Abstract. The Southern Hemisphere Westerly Winds (SWW) constitute an important zonal circulation system that dominates the dynamics of Southern Hemisphere mid-latitude climate. Little is known about climatic changes in the Southern South America in comparison to the Northern Hemisphere due to the low density of proxy records, and adequate chronology and sampling resolution to address environmental changes of the last 2000 years. Since 2009, new pollen and charcoal records from bog and lakes in northern and southern Patagonia at the east side of the Andes have been published with an adequate calibration of pollen assemblages related to modern vegetation and ecological behaviour. In this work we improve the chronological control of some eastern Andean previously published sequences and integrate pollen and charcoal dataset available east of the Andes to interpret possible environmental and SWW variability at centennial time scales. Through the analysis of modern and past hydric balance dynamics we compare these scenarios with other western Andean SWW sensitive proxy records for the last 2000 years. Due to the distinct precipitation regimes that exist between Northern (40–45° S) and Southern Patagonia (48–52° S) pollen sites locations, shifts on latitudinal and strength of the SWW results in large changes on hydric availability on forest and steppe communities. Therefore, we can interpret fossil pollen dataset as changes on paleohydric balance at every single site by the construction of paleohydric indices and comparison to charcoal records during the last 2000 cal yrs BP. Our composite pollen-based Northern and Southern Patagonia indices can be interpreted as changes in latitudinal variation and intensity of the SWW respectively. Dataset integration suggest poleward SWW between 2000 and 750 cal yrs BP and northward-weaker SWW during the Little Ice Age (750–200 cal yrs BP). These SWW variations are synchronous to Patagonian fire activity major shifts. We found an in phase fire regime (in terms of timing of biomass burning) between northern Patagonia Monte shrubland and Southern Patagonia steppe environments. Conversely, there is an antiphase fire regime between Northern and Southern Patagonia forest and forest-steppe ecotone environments. SWW variability may be associated to ENSO variability especially during the last millennia. For the last 200 cal yrs BP we can concluded that the SWW belt were more intense and poleward than the previous interval. Our composite pollen-based SWW indices show the potential of pollen dataset integration to improve the understanding of paleohydric variability especially for the last 2000 millennial in Patagonia.

scholarly journals Recover and They’ll Come: Flower Visiting Bees Benefit from the Continuous of Micro-Environments Set by Regenerating Forest Fragments

Sociobiology ◽  
2021 ◽  
Vol 68 (1) ◽  
pp. 5861
Author(s):  
Ana Isabel Sobreiro ◽  
Lucas Lopes da Silveira Peres ◽  
Jessica Amaral Henrique ◽  
Rosilda Mara Mussury ◽  
Valter Vieira Alves-Junior
Keyword(s):  
Urban Areas ◽  
Environmental Changes ◽  
Climatic Conditions ◽  
Agricultural Activity ◽  
Forest Fragments ◽  
Forest Types ◽  
Continuous Forest ◽  
Flower Visiting ◽  
Bee Communities ◽  
Forest Habitats

Forest habitats are important sources of food and nesting resources for pollinators, primarily in urban areas and landscapes with intense agricultural activity. The forest fragmentation and environmental changes occurring in these green refuges are known to impose survival challenges to pollinating bees, leading to species loss. However, it is not well known how the species of bees that visit flowers are distributed in forest micro-environments. To fill this gap, we sampled flower visiting bees in a continuous forest matrix with micro-environments of two forest types (mature and regenerating forest). We examined how the local environmental changes and climatic conditions affect the composition and uniformity of bee communities in the different micro-environments. Our results indicated that both abundance and richness were similar between forest types studied here, however climatic conditions and plant flowering patterns affect the composition of bees. Thus, our results demonstrated that the continuous micro-environments can favor floral visits and the reintegration of bee communities, and still, that this strategy can be used to minimize the impacts of environmental changes at local scales.

Paleoenvironmental reconstruction of the central Levantine Corridor during the Pliocene: insights from lacustrine settings 

2021 ◽  
Author(s):  
John Greenlee ◽  
Silas Dean ◽  
Nicolas Waldmann
Keyword(s):  
High Resolution ◽  
Data Science ◽  
Environmental Changes ◽  
Laser Diffraction ◽  
Climatic Conditions ◽  
Paleoenvironmental Reconstruction ◽  
Cosmogenic Isotopes ◽  
X Ray ◽  
Geochemical Proxies ◽  
Favorable Conditions

<p>This study aims to reconstruct the paleoenvironmental and climatic conditions affecting the Levantine corridor during the early Pliocene. For the purpose of this study, a ~20 m continuous core sequence was retrieved out of the ~200 m long, tilted Erk el Ahmar sequence previously dated by cosmogenic isotopes to ~3.5 Ma. The record include intercalating units consisting of sands, silts, and clays that were sampled in high resolution in order to analyze a variety of sedimentological and geochemical proxies of past climate and environmental changes. We present new preliminary, high-resolution sedimentological (laser diffraction granulometry), petrophysical (magnetic susceptibility) and compositional (X-ray fluorescence) data along with accompanying statistical analysis performed with an advanced suite of data-science tools. These results reveal new cycles of environmental change in the area, which appears to be orbitally controlled, and include dramatic changes also indicated by discrete strata of fossil fragments. Moreover, cycles of deposition can also provide hints on the major hydrological controlling mechanisms. This project provides new light into favorable conditions for the subsistence of perennial lake environments in the Levantine Corridor, which in turn may have facilitated faunal migration between Africa and Eurasia.</p>

scholarly journals Influence of the Management on the Phytocoenotic Biodiversity of Some Romanian Representative Grassland Types

2011 ◽  
Vol 39 (1) ◽  
pp. 119
Author(s):  
Vasile VÂNTU ◽  
Costel SAMUIL ◽  
Ioan ROTAR ◽  
Alexandru MOISUC ◽  
Iosif RAZEC
Keyword(s):  
Trifolium Repens ◽  
Poa Pratensis ◽  
Climatic Conditions ◽  
Organic Fertilizers ◽  
Agrostis Capillaris ◽  
Pastoral Area ◽  
Yield And Quality ◽  
Grassland Ecosystems ◽  
Calamagrostis Epigeios

The pastoral area of Romania, covering of over 4.8 million ha, has been influenced, over the last decades, by natural and human factors, which affect the normal functioning of the grassland ecosystem. The aim of this paper is to point out the dynamics of phytocoenotic biodiversity, as a result of applying grassland technical measures, in order to improve the yield and quality of grassland ecosystems with minimum effects on the environment. Therefore, the main aim of our study is to establish a positive relationship between biodiversity and the optimum quantity of organic fertilizers, which would improve the quality and quantity of the yield, without diminishing the floristic biodiversity. In the case of the studied grasslands, the phytocenotic biodiversity is influenced by the type of fertilization, the used rates and by the soil and climatic conditions. These grasslands may be improved by manure fertilization and reasonable usage, if proper management is applied. In Gradinari, Caras-Severin county, the dominant species are Festuca rupicola and Calamagrostis epigeios, in Magurele, Brasov county, Agrostis capillaris, Festuca pratensis, Poa pratensis and Trifolium repens, and in Pojorata, Suceava county, Agrostis capillaris, Trisetum flavescens, Trifolium repens and T. pratense species. The highest number of identified species (43) has been recorded by the meadow made up of Agrostis capillaris and Festuca rubra, from Pojorata, Suceava county.

scholarly journals Radiocarbon Analysis Confirms the Annual Nature of Sagebrush Growth Rings

Radiocarbon ◽  
2007 ◽  
Vol 49 (3) ◽  
pp. 1231-1240 ◽  
Author(s):  
Franco Biondi ◽  
Scotty D J Strachan ◽  
Scott Mensing ◽  
Gianluca Piovesan
Keyword(s):  
Great Basin ◽  
Cross Sections ◽  
Environmental Changes ◽  
Spatially Explicit ◽  
Growth Rings ◽  
Ams Radiocarbon Dating ◽  
Big Sagebrush ◽  
Proxy Records ◽  
Annual Resolution ◽  
Wildfire Regimes

In the Great Basin of North America, big sagebrush (Artemisia tridentata Nutt.) growth rings can be used to reconstruct environmental changes with annual resolution in areas where there is otherwise little such information available. We tested the annual nature of big sagebrush wood layers using accelerator mass spectrometry (AMS) radiocarbon dating. Four cross-sections from 3 sagebrush plants were collected near Ely, Nevada, USA, and analyzed using dendrochronological methods. Ten 14C measurements were then used to trace the location of the 1963–64 “bomb spike.” Although the number of rings on each section did not exceed 60, crossdating was possible within a section and between sections. Years assigned to individual wood layers by means of crossdating aligned with their expected 14C values, matching the location of the 14C peak. This result confirmed the annual nature of growth rings formed by big sagebrush, and will facilitate the development of spatially explicit, well-replicated proxy records of environmental change, such as wildfire regimes, in Great Basin valleys.

Long-Term Ecological Research and Evolving Frameworks of Disturbance Ecology

BioScience ◽  
2020 ◽  
Vol 70 (2) ◽  
pp. 141-156 ◽  
Author(s):  
Evelyn E Gaiser ◽  
David M Bell ◽  
Max C N Castorani ◽  
Daniel L Childers ◽  
Peter M Groffman ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Global Environmental Change ◽  
Disturbance Ecology ◽  
Ecological Systems ◽  
Environmental Drivers ◽  
Global Changes ◽  
Ecological Research ◽  
Social Ecological ◽  
Long Term Ecological Research

Abstract Detecting and understanding disturbance is a challenge in ecology that has grown more critical with global environmental change and the emergence of research on social–ecological systems. We identify three areas of research need: developing a flexible framework that incorporates feedback loops between social and ecological systems, anticipating whether a disturbance will change vulnerability to other environmental drivers, and incorporating changes in system sensitivity to disturbance in the face of global changes in environmental drivers. In the present article, we review how discoveries from the US Long Term Ecological Research (LTER) Network have influenced theoretical paradigms in disturbance ecology, and we refine a framework for describing social–ecological disturbance that addresses these three challenges. By operationalizing this framework for seven LTER sites spanning distinct biomes, we show how disturbance can maintain or alter ecosystem state, drive spatial patterns at landscape scales, influence social–ecological interactions, and cause divergent outcomes depending on other environmental changes.

Efficiency of correction of autonomic disorders in the conditions of meteo-climatic maladaptation by the methods of reflex and crystal therapy

2015 ◽  
Vol 9 (4) ◽  
pp. 0-0
Author(s):  
Михайлова ◽  
A. Mikhaylova ◽  
Круглянин ◽  
K. Kruglyanin ◽  
Файзуллоев ◽  
...  
Keyword(s):  
Nervous System ◽  
Environmental Changes ◽  
Climatic Conditions ◽  
The Body ◽  
Controlled Study ◽  
Health Improvement ◽  
Control Group ◽  
Vegetative Nervous System ◽  
Significant Difference ◽  
Autonomic Disorders

The change of climatic conditions often leads to stress and sometimes failure of adaptive resources. Vegetative nervous system is one of the main participants of adaptation to environmental changes. Its functions inevitably decline in cases of short-term change of meteorological and climatic conditions, especially, in people with history of vascular dystonia. The article presents the results of correction of the autonomic function by the methods of reflex- and crystal therapy in the conditions of maladaptation due to meteo-climatic changes. Due to its popularization in world medical practice and absence of research within evidence-based medicine, non-drug therapy, used in complementary medicine, in particular crystal therapy, require evaluation of its effectiveness for correction of autonomic disorders in cases of maladaptation and comparing with the generally accepted method of reflexology. Crystal therapy is a method of health improvement, which involves applying precious and semiprecious minerals to various parts of the body. Assessment of vegetative nervous system in healthy men and women with the diagnosis of vascular dystonia was carried out on the first day and 7-8 days after the arrival to Anapa. Randomized, blind, placebo controlled study has shown significant difference of the effect of reflex- and crystal therapy from the control group and the placebo group, in the correction of vegetative disturbances according to the heart rate variability and a number of mental health indicators. It has proven the effectiveness of reflexotherapy in the case of a high degree of maladaptation and crystal therapy in case of mild to moderate severity of maladaptation, identified according to the coefficient of weather variability in traffic along various routes.

scholarly journals Forecasting the impacts of chemical pollution and climate change interactions on the health of wildlife

2015 ◽  
Vol 61 (4) ◽  
pp. 669-689 ◽  
Author(s):  
Pamela D. Noyes ◽  
Sean C. Lema
Keyword(s):  
Climate Change ◽  
Environmental Changes ◽  
Global Climate ◽  
Climatic Conditions ◽  
Future Climate ◽  
Chemical Pollution ◽  
Climate Scenarios ◽  
Chemical Toxicity ◽  
Climate Conditions ◽  
Chemical Exposures

Abstract Global climate change is impacting organisms, biological communities and ecosystems around the world. While most research has focused on characterizing how the climate is changing, including modeling future climatic conditions and predicting the impacts of these conditions on biodiversity, it is also the case that climate change is altering the environmental impacts of chemical pollution. Future climate conditions are expected to influence both the worldwide distribution of chemicals and the toxicological consequences of chemical exposures to organisms. Many of the environmental changes associated with a warming global climate (e.g., increased average – and possibly extreme – temperatures; intense periods of drier and wetter conditions; reduced ocean pH; altered salinity dynamics in estuaries) have the potential to enhance organism susceptibility to chemical toxicity. Additionally, chemical exposures themselves may impair the ability of organisms to cope with the changing environmental conditions of the shifting climate. Such reciprocity in the interactions between climate change and chemicals illustrates the complexity inherent in predicting the toxicological consequences of chemical exposures under future climate scenarios. Here, we summarize what is currently known about the potential reciprocal effects of climate change and chemical toxicity on wildlife, and depict current approaches and ongoing challenges for incorporating climate effects into chemical testing and assessment. Given the rapid pace of new man-made chemistries, the development of accurate and rapid methods to evaluate multiple chemical and non-chemical stressors in an ecologically relevant context will be critical to understanding toxic and endocrine-disrupting effects of chemical pollutants under future climate scenarios.

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