The Ecology and Management of Wood in World Rivers

2003 ◽  
Keyword(s):  
Life Histories ◽  
Land Use Changes ◽  
Aquatic Organisms ◽  
Life Cycles ◽  
Large Wood ◽  
Ecological Processes ◽  
History Of ◽  
Warmwater Fish ◽  
Nest Materials ◽  
World Rivers

<em>Abstract.</em>—Many ecological processes are associated with large wood in streams, such as forming habitat critical for fish and a host of other organisms. Wood loading in streams varies with age and species of riparian vegetation, stream size, time since last disturbance, and history of land use. Changes in the landscape resulting from homesteading, agriculture, and logging have altered forest environments, which, in turn, changed the physical and biological characteristics of many streams worldwide. Wood is also important in creating refugia for fish and other aquatic species. Removing wood from streams typically results in loss of pool habitat and overall complexity as well as fewer and smaller individuals of both coldwater and warmwater fish species. The life histories of more than 85 species of fish have some association with large wood for cover, spawning (egg attachment, nest materials), and feeding. Many other aquatic organisms, such as crayfish, certain species of freshwater mussels, and turtles, also depend on large wood during at least part of their life cycles.

The Ecology and Management of Wood in World Rivers

2003 ◽  
Keyword(s):  
Land Management ◽  
Management Practices ◽  
Riparian Forests ◽  
Floodplain Forests ◽  
Large Wood ◽  
Ecological Processes ◽  
Rivers And Streams ◽  
World Rivers ◽  
Continuous Source

<em>Abstract.</em>—Riparian and floodplain forests are vital components of landscapes. They are transitional zones (ecotones) between river and upland ecosystems where ecological processes occurring in riparian areas and floodplains connect and interact with those of rivers and streams. These forests are the major source of large wood for streams and rivers. Extensive loss of riparian and floodplain forests around the globe is evident from the dramatically reduced supply of large wood in rivers. Clearly, it is necessary to conserve and restore riparian forests to sustain a supply of wood for rivers. This chapter discusses river and land management practices that are designed to provide a continuous source of large wood for rivers and retain wood once it has entered the channel or floodplain. These management practices include conservation of intact riparian and floodplain forests, restoration of ecological processes necessary to sustain riparian forests in the long term, and management of riparian forests specifically to accelerate recruitment of large wood to rivers and streams.

Coevolutionary interactions between host life histories and parasite life cycles

Parasitology ◽  
1998 ◽  
Vol 116 (S1) ◽  
pp. S47-S55 ◽  
Author(s):  
J. C. Koella ◽  
P. Agnew ◽  
Y. Michalakis
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Life Histories ◽  
Life History Traits ◽  
Evolutionary Ecology ◽  
Life Cycles ◽  
Microsporidian Parasite ◽  
History Of ◽  
Host Life ◽  
Host Parasite

SummarySeveral recent studies have discussed the interaction of host life-history traits and parasite life cycles. It has been observed that the life-history of a host often changes after infection by a parasite. In some cases, changes of host life-history traits reduce the costs of parasitism and can be interpreted as a form of resistance against the parasite. In other cases, changes of host life-history traits increase the parasite's transmission and can be interpreted as manipulation by the parasite. Alternatively, changes of host's life-history traits can also induce responses in the parasite's life cycle traits. After a brief review of recent studies, we treat in more detail the interaction between the microsporidian parasite Edhazardia aedis and its host, the mosquito Aedes aegypti. We consider the interactions between the host's life-history and parasite's life cycle that help shape the evolutionary ecology of their relationship. In particular, these interactions determine whether the parasite is benign and transmits vertically or is virulent and transmits horizontally.Key words: host-parasite interaction, life-history, life cycle, coevolution.

scholarly journals Land Use Dynamics and Optimization from 2000 to 2020 in East Guangdong Province, China

2021 ◽  
Vol 13 (6) ◽  
pp. 3473
Author(s):  
Yong Lai ◽  
Guangqing Huang ◽  
Shengzhong Chen ◽  
Shaotao Lin ◽  
Wenjun Lin ◽  
...  
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Landscape Connectivity ◽  
Land Use Changes ◽  
Research Result ◽  
Global Environmental Change ◽  
Ecological Processes ◽  
Buffer Zones ◽  
Conflict Zones ◽  
Land Use Dynamics

Anthropogenic land-use change is one of the main drivers of global environmental change. China has been on a fast track of land-use change since the Reform and Opening-up policy in 1978. In view of the situation, this study aims to optimize land use and provide a way to effectively coordinate the development and ecological protection in China. We took East Guangdong (EGD), an underdeveloped but populous region, as a case study. We used land-use changes indexes to demonstrate the land-use dynamics in EGD from 2000 to 2020, then identified the hot spots for fast-growing areas of built-up land and simulated land use in 2030 using the future land-use simulation (FLUS) model. The results indicated that the cropland and the built-up land changed in a large proportion during the study period. Then we established the ecological security pattern (ESP) according to the minimal cumulative resistance model (MCRM) based on the natural and socioeconomic factors. Corridors, buffer zones, and the key nodes were extracted by the MCRM to maintain landscape connectivity and key ecological processes of the study area. Moreover, the study showed the way to identify the conflict zones between future built-up land expansion with the corridors and buffer zones, which will be critical areas of consideration for future land-use management. Finally, some relevant policy recommendations are proposed based on the research result.

scholarly journals Current understanding on the Cambrian Explosion: questions and answers

PalZ ◽  
2021 ◽  
Author(s):  
Xingliang Zhang ◽  
Degan Shu
Keyword(s):  
Environmental Changes ◽  
Size Variation ◽  
Progressive Increase ◽  
Cambrian Explosion ◽  
Time Interval ◽  
Early Cambrian ◽  
Ecological Processes ◽  
Questions And Answers ◽  
Evolutionary Event ◽  
History Of

AbstractThe Cambrian Explosion by nature is a three-phased explosion of animal body plans alongside episodic biomineralization, pulsed change of generic diversity, body size variation, and progressive increase of ecosystem complexity. The Cambrian was a time of crown groups nested by numbers of stem groups with a high-rank taxonomy of Linnaean system (classes and above). Some stem groups temporarily succeeded while others were ephemeral and underrepresented by few taxa. The high number of stem groups in the early history of animals is a major reason for morphological gaps across phyla that we see today. Most phylum-level clades achieved their maximal disparity (or morphological breadth) during the time interval close to their first appearance in the fossil record during the early Cambrian, whereas others, principally arthropods and chordates, exhibit a progressive exploration of morphospace in subsequent Phanerozoic. The overall envelope of metazoan morphospace occupation was already broad in the early Cambrian though it did not reach maximal disparity nor has diminished significantly as a consequence of extinction since the Cambrian. Intrinsic and extrinsic causes were extensively discussed but they are merely prerequisites for the Cambrian Explosion. Without the molecular evolution, there could be no Cambrian Explosion. However, the developmental system is alone insufficient to explain Cambrian Explosion. Time-equivalent environmental changes were often considered as extrinsic causes, but the time coincidence is also insufficient to establish causality. Like any other evolutionary event, it is the ecology that make the Cambrian Explosion possible though ecological processes failed to cause a burst of new body plans in the subsequent evolutionary radiations. The Cambrian Explosion is a polythetic event in natural history and manifested in many aspects. No simple, single cause can explain the entire phenomenon.

scholarly journals Robustness of life histories to environmental variability in complex versus simple life cycles

2021 ◽  
Author(s):  
Annie Jonsson
Keyword(s):  
Growth Rate ◽  
Life Histories ◽  
Environmental Variability ◽  
Life Cycles ◽  
Relative Advantage ◽  
Complex Life Cycle ◽  
Life Stages ◽  
Vital Rates ◽  
Habitat Separation ◽  
Simple Life

AbstractMost animal species have a complex life cycle (CLC) with metamorphosis. It is thus of interest to examine possible benefits of such life histories. The prevailing view is that CLC represents an adaptation for genetic decoupling of juvenile and adult traits, thereby allowing life stages to respond independently to different selective forces. Here I propose an additional potential advantage of CLCs that is, decreased variance in population growth rate due to habitat separation of life stages. Habitat separation of pre- and post-metamorphic stages means that the stages will experience different regimes of environmental variability. This is in contrast to species with simple life cycles (SLC) whose life stages often occupy one and the same habitat. The correlation in the fluctuations of the vital rates of life stages is therefore likely to be weaker in complex than in simple life cycles. By a theoretical framework using an analytical approach, I have (1) derived the relative advantage, in terms of long-run growth rate, of CLC over SLC phenotypes for a broad spectrum of life histories, and (2) explored which life histories that benefit most by a CLC, that is avoid correlation in vital rates between life stages. The direction and magnitude of gain depended on life history type and fluctuating vital rate. One implication of our study is that species with CLCs should, on average, be more robust to increased environmental variability caused by global warming than species with SLCs.

scholarly journals Cycles and circulation: a theme in the history of biology and medicine

2021 ◽  
Vol 43 (3) ◽  
Author(s):  
Nick Hopwood ◽  
Staffan Müller-Wille ◽  
Janet Browne ◽  
Christiane Groeben ◽  
Shigehisa Kuriyama ◽  
...  
Keyword(s):  
Natural Philosophy ◽  
Life Cycles ◽  
Modern Times ◽  
Systems Ecology ◽  
The Face ◽  
History Of ◽  
Celestial Bodies ◽  
Reproductive Cycles ◽  
Economics And Biology

AbstractWe invite systematic consideration of the metaphors of cycles and circulation as a long-term theme in the history of the life and environmental sciences and medicine. Ubiquitous in ancient religious and philosophical traditions, especially in representing the seasons and the motions of celestial bodies, circles once symbolized perfection. Over the centuries cyclic images in western medicine, natural philosophy, natural history and eventually biology gained independence from cosmology and theology and came to depend less on strictly circular forms. As potent ‘canonical icons’, cycles also interacted with representations of linear and irreversible change, including arrows, arcs, scales, series and trees, as in theories of the Earth and of evolution. In modern times life cycles and reproductive cycles have often been held to characterize life, in some cases especially female life, while human efforts selectively to foster and disrupt these cycles have harnessed their productivity in medicine and agriculture. But strong cyclic metaphors have continued to link physiology and climatology, medicine and economics, and biology and manufacturing, notably through the relations between land, food and population. From the grand nineteenth-century transformations of matter to systems ecology, the circulation of molecules through organic and inorganic compartments has posed the problem of maintaining identity in the face of flux and highlights the seductive ability of cyclic schemes to imply closure where no original state was in fact restored. More concerted attention to cycles and circulation will enrich analyses of the power of metaphors to naturalize understandings of life and their shaping by practical interests and political imaginations.

A comparative study of the life histories of Nematodirus battus and N. filicollis, nematode parasites of sheep

Parasitology ◽  
1959 ◽  
Vol 49 (3-4) ◽  
pp. 374-386 ◽  
Author(s):  
R. J. Thomas
Keyword(s):  
Life History ◽  
Intestinal Mucosa ◽  
Related Species ◽  
Life Histories ◽  
Basic Pattern ◽  
Culture Methods ◽  
Closely Related Species ◽  
Nematode Parasites ◽  
History Of ◽  
Comparative Description

1. The life history of N. battus is described, and a comparative description of the life history of N. filicollis is given.2. The life histories of these two species are compared with those of N. spathiger and N. helvetianus, two closely related species, and are shown to follow the same basic pattern, with minor variations in timing which appear to be specific in nature, and not related to differences in culture methods or host species.3. The pathogenesis of Nematodirus species is discussed and related to the migration of larvae into the intestinal mucosa during development.

III.—The Life-history and Cytology of Didymium nigripes Fr.

1932 ◽  
Vol 57 (1) ◽  
pp. 93-142 ◽  
Author(s):  
Elsie J. Cadman
Keyword(s):  
Life History ◽  
Life Histories ◽  
Important Research ◽  
Great Work ◽  
Animal Kingdom ◽  
History Of ◽  
Natural Groups

Since 1860, in which year De Bary published his great work Die Mycetozoen, the investigation of the life-history of members of the Mycetozoa has aroused a considerable amount of interest, and a great deal of important research has been carried out in this connection. The group of organisms is particularly interesting, because it lies on the borderline between plant and animal kingdoms, and it is very possible that a detailed investigation of several species of the Mycetozoa might be of considerable assistance in elucidating certain obscure points in the life-histories of higher members of both the great natural groups. The term “Mycetozoa,” which we owe to De Bary, will be used throughout in preference to the older term “Myxogastres” invented by Fries (32, p. 2), and that of “Myxomycetes” first employed by Link (32, p. 2). “Mycetozoon,” or “fungus-like animal,” is a very appropriate description of a member of the group, since during part of its life-history it exhibits distinctly animal-like characters, and the individuals move rapidly by means of flagella, whilst later, during the development of the sporangium, a plant-like form is assumed. The combination of plant and animal characters has given rise to much discussion as to the position of the Mycetozoa in plant or animal kingdom, and the group has been claimed by both zoologists and botanists.

A Cultural History of Education in the Modern Age

2020 ◽  
Keyword(s):  
Cultural History ◽  
Life Histories ◽  
History Of Education ◽  
Political Transformation ◽  
Modern Age ◽  
History Of ◽  
Children And Childhood ◽  
Essential Resource ◽  
Literature Culture ◽  
The Many

The twentieth century brought profound and far-reaching changes to education systems globally in response to significant social, economic, and political transformation. This volume draws together work from leading historians of education to present a tapestry of seminal and enduring themes that characterize the many educational developments since 1920. An essential resource for researchers, scholars, and students in history, literature, culture, and education, A Cultural History of Education in the Modern Age presents essays that examine the following key themes of the period: church, religion and morality; knowledge, media and communications; children and childhood; family, community and sociability; learners and learning; teachers and teaching; literacies; and life histories.

scholarly journals The application of life history information to the conservation management of Chrysoritis butterflies (Lepidoptera: Lycaenidae) in South Africa

Koedoe ◽  
2004 ◽  
Vol 47 (1) ◽  
Author(s):  
R.F. Terblanche ◽  
H. Van Hamburg
Keyword(s):  
South Africa ◽  
Life History ◽  
Life Histories ◽  
Host Plants ◽  
Conservation Management ◽  
Aesthetic Value ◽  
Wing Patterns ◽  
In The Wild ◽  
History Of ◽  
Voucher Specimens

Due to their intricate life histories and the unique wing patterns and colouring the butterflies of the genus Chrysoritis are of significant conservation and aesthetic value. Thisoverview probes into practical examples of butterfly life history research applicable to environmental management of this relatively well-known invertebrate group in South Africa. Despite the pioneer work on life histories of Chrysoritis in the past, more should be done to understand the life history of the butterflies in the wild, especially their natural host plants and the behaviour of adults and larvae. A system of voucher specimens of host plants should be introduced in South Africa. Although various host plant species in nature are used by the members of Chrysoritis, including the Chrysoritis chrysaor group, the choice of these in nature by each species is significant for conservation management and in the case of Chrysoritis aureus perhaps even as a specific characteristic.A revision of the ant genus Crematogaster will benefit the conservation management of Chrysoritis species since some of these ant species may consist of a number of specieswith much more restricted distributions than previously thought. Rigorous quantified tudies of population dynamics of Chrysoritis butterflies are absent and the introductionof such studies will benefit conservation management of these localised butterflies extensively.

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