Ecological succession as an aspect of structure in fossil communities

Paleobiology ◽  
1975 ◽  
Vol 1 (3) ◽  
pp. 238-257 ◽  
Author(s):  
Kenneth R. Walker ◽  
Leonard P. Alberstadt
Keyword(s):  
Environmental Changes ◽  
Food Chains ◽  
Short Term ◽  
Niche Specialization ◽  
Pattern Diversity ◽  
Physical Environments ◽  
Autogenic Succession ◽  
Succession Stage ◽  
Stratigraphic Sequences

Succession involves changes in a community through time, whether internally or externally controlled. As succession progresses, niche specialization, species diversity (variety and equitability), complexity of food chains, and pattern diversity increase; net production and species growth rate decrease. We apply the succession concept to three types of ancient community sequences: 1) fossil reefs (Ordovician—Cretaceous in age), 2) short-term successions occurring through thin stratigraphic intervals, and 3) long-term successions occurring through thicker stratigraphic intervals. Ancient reefs show four vertical zones: (1) a basal stabilization zone (autogenic), 2) the overlying colonization zone (autogenic, pioneer stage), 3) the diversification zone, the bulk of most reefs (diversification culminating in climax), and 4) the uppermost domination zone. The first three zones represent autogenic succession but the final stage may involve allogenic succession. Short-term succession usually occurs where periodic allogenic catastrophes wipe out the community which is rebuilt through autogenic succession. Opportunistic pioneer species are important and in our examples (Ordovician, Silurian, and Cretaceous) are species which pave soft substrata. Paleozoic strophomenid brachiopods filled this role, and inoceramid pelecypods served the function in the Mesozoic. The succession which begins with opportunists progresses to a climax community of equilibrists. Repetition of catastrophe-succession couplets produces a cyclic stratigraphic record. Long-term successions are recorded in thicker stratigraphic sequences, and are of two types: 1) autogenic succession in unchanging physical environments and 2) allogenic succession in changing physical environments. Our examples of these are from the Devonian Haragan-Bois D'Arc formations of Oklahoma and the Lime Creek Formation of Iowa. This type of succession represents a temporal-spatial mosaic. The Haragan data (unchanging environments) indicate characteristic, intergrading, and ubiquitous species in the brachiopod communities. Most ubiquitous species in the pioneer community were eurytopic opportunists. The Lime Creek data allows testing of the prediction that environmental changes cause regression to an earlier succession stage. The brachiopod communities after environmental changes have more ubiquitous and intergrading eurytopic species. These represent an earlier stage in the succession.

scholarly journals NATURE AND THE CITY: A CO-EVOLUTIONARY PROJECT

2014 ◽  
Vol 38 (3) ◽  
pp. 198-204 ◽  
Author(s):  
Samir Younés
Keyword(s):  
Environmental Changes ◽  
International Agreements ◽  
Regional Level ◽  
Deep Ecology ◽  
Earth System ◽  
Short Term ◽  
Traditional Architecture ◽  
Gaia Theory ◽  
The City

Architects who understand the need to build enduringly are faced with the almost complete absence of international agreements with respect to a planetary ecological project. The coming environmental changes will probably occur long before the small measures that can be implemented by some building industries on a regional level have even the slightest effect. Meanwhile, the health of the planet in positive feedback. Any project that aims for a wise ecological dwelling on this planet needs to consider short-term sustainable measures in comparison with long-term enduring practices. Might schools of thoughts such as traditional architecture, Gaia theory, Earth System Science, deep ecology, eco-feminism, converge on a co-evolutionary partnership between the natural and the human?

scholarly journals A Simulation Model of the Decomposition Activity of Multiple Fungi

2021 ◽  
Vol 267 ◽  
pp. 02028
Author(s):  
Ruoxuan Liu ◽  
Jianhui Ye
Keyword(s):  
Environmental Changes ◽  
Colony Growth ◽  
Short Term ◽  
Model Decomposition ◽  
Decomposition Model ◽  
Fungal Activity ◽  
Single Colony ◽  
Extension Model ◽  
The Relationship

Fungi play an essential role in carbon cycle by decomposing the litter and woody fibers. This study aims to establish a model for describing the decomposition by multiple fungal activities in different environment. We establish Colony Distribution-Decomposition Model to simulate the interaction between various fungi and describe the relationship between fungal activity and decomposition, which is divided into three sub-models: single colony growth and extension model, decomposition model and competition model. We applied this model to the study of the interaction of different species, the sensitivity of fungi to environmental changes in short-term and long-term, the adapatability to different climate types for various species and the role biodiversity plays in the breakdown of the litter. The developed model has the advantages of comprehensiveness, stability, rationality, and wide application, which is a feasible and reasonable model to assist the analysis on the interaction between multiple fungi and describe the relationship between fungal activity and decomposition.

Aspects of Psychological Aging and Technology

1985 ◽  
Vol 1 (1) ◽  
pp. 117-121
Author(s):  
Stig Berg
Keyword(s):  
Genetic Factors ◽  
Environmental Changes ◽  
Eating Habits ◽  
Social Resources ◽  
Psychological Resources ◽  
Age Changes ◽  
Short Term ◽  
Technological Factors ◽  
The Individual

Aging is generally regarded as a reduction of physical, psychological, and social resources. This reduction is due to two processes that operate simultaneously during the life of an individual. One of these processes is the basic biological changes which take place within the individual and are probably programmed by genetic factors. The other is change due to environmental factors, such as air pollution, noise, poor working conditions, and eating habits, social and psychological factors such as attitudes and norms, and technological factors which can enhance adaptation or cause a decline in social or psychological resources. According to present knowledge, biological age changes are irreversible. However, it should be possible to reverse the environmental changes either through short-term interventions among individuals and the community, or by long-term interventions in the society.

Childhood Coping: Avoiding a Lifetime of Anxiety

1992 ◽  
Vol 9 (4) ◽  
pp. 229-237 ◽  
Author(s):  
Philip C. Kendall
Keyword(s):  
Cognitive Skills ◽  
Environmental Changes ◽  
Intervention Strategies ◽  
Social Judgments ◽  
Short Term ◽  
Ideal Situation ◽  
The Social ◽  
The Family ◽  
The Ideal

Short-term social judgments that involve avoidance can contribute to the production of a habit that forecloses on later adaptation. When a child uses avoidance in one setting, and then in another, the child may have already begun the foreclosure process. Short-term decisions have long-term consequences, and to reduce anxious avoidance in youth is to increase long-range opportunities. Teaching behavioural and cognitive skills to increase social competence and adaptation will increase opportunities and increase choice. In the ideal situation, the plan is to encourage the development of coping skills, to encourage the family and the school to provide opportunities for coping, and to encourage the social system to provide the rewards that will maintain nonanxious nonavoidant behaviour. The thrust of this presentation is (a) to review and integrate behavioural and cognitive theories that guide us to understand the nature of anxiety in youth, (b) to describe intervention strategies that build childhood coping, and (c) to consider the necessary environmental changes that are needed to maintain treatment-produced gains.

scholarly journals Effect of Short and Long Term Restraint Stress on the Histology of Liver, Kidney and Suprarenal Gland in Albino Mice during Postweaning Period

2021 ◽  
pp. 6-19
Author(s):  
Othman Hakum Said ◽  
Chukwuma J. Okafor ◽  
Hassan Thabit Haji ◽  
Prakash B. Babu ◽  
Vanisri S. Nayak ◽  
...  
Keyword(s):  
Adrenal Cortex ◽  
Restraint Stress ◽  
Cell Injury ◽  
Environmental Changes ◽  
Morphological Changes ◽  
Short Term ◽  
Suprarenal Gland ◽  
Albino Mice ◽  
Convoluted Tubules

On exposure to stress and for the sake of survival, cells make adjustments with the changes in their environment to the physiologic needs and non-lethal pathologic injury. When the environmental changes are greater than the capacity of the cell to maintain normal homeostasis the cell undergoes acute cell injury. If the injury or insult is removed on time, or the cell can adapt and withstand the injury, the term reversible injury is applied. The processes of adaptation include decreasing or increasing their size, increasing their number, or changing the pathway of phenotypic differentiation of cells. In the present study, albino mice of postweaning age of BALB C strain (21 days old) were exposed to short term (5 days) and long term (21 days) restraint stress to evaluate any histological changes in the kidney, liver, and suprarenal gland. Mice subjected to long term stress showed in the kidney degeneration of the cells of the glomerulus and the convoluted tubules. In the liver, they showed congested sinusoids and the presence of some fatty change, whereas in the suprarenal gland mice subjected to 21 days of stress showed moderate hypertrophy and hyperplasia of the adrenal cortex with the presence of moderate lipoid deposits when compared to controls. The overall effect on short term stress was mild when compared to exposure to 21 days stress Long term stress causes degeneration in hepatic cells, infiltration in the liver, degeneration of glomerulus, Bowman’s capsule, convoluted tubules in the kidney which could lead to nephrotoxicity. In the suprarenal gland, long term stress induces hypertrophy of the adrenal cortex. These morphological changes can explain the impaired immunity which develops in organisms that are exposed to chronic stress.

scholarly journals Foraging efficiency in temporally predictable environments: is a long-term temporal memory really advantageous?

2021 ◽  
Vol 8 (9) ◽  
pp. 210809
Author(s):  
Benjamin Robira ◽  
Simon Benhamou ◽  
Shelly Masi ◽  
Violaine Llaurens ◽  
Louise Riotte-Lambert
Keyword(s):  
Environmental Changes ◽  
Short Term Memory ◽  
Temporal Information ◽  
Food Sources ◽  
Foraging Efficiency ◽  
Recent Experience ◽  
Short Term ◽  
Temporal Memory ◽  
Temporal Cognition

Cognitive abilities enabling animals that feed on ephemeral but yearly renewable resources to infer when resources are available may have been favoured by natural selection, but the magnitude of the benefits brought by these abilities remains poorly known. Using computer simulations, we compared the efficiencies of three main types of foragers with different abilities to process temporal information, in spatially and/or temporally homogeneous or heterogeneous environments. One was endowed with a sampling memory, which stores recent experience about the availability of the different food types. The other two were endowed with a chronological or associative memory, which stores long-term temporal information about absolute times of these availabilities or delays between them, respectively. To determine the range of possible efficiencies, we also simulated a forager without temporal cognition but which simply targeted the closest and possibly empty food sources, and a perfectly prescient forager, able to know at any time which food source was effectively providing food. The sampling , associative and chronological foragers were far more efficient than the forager without temporal cognition in temporally predictable environments, and interestingly, their efficiencies increased with the level of temporal heterogeneity. The use of a long-term temporal memory results in a foraging efficiency up to 1.16 times better ( chronological memory) or 1.14 times worse ( associative memory) than the use of a simple sampling memory. Our results thus show that, for everyday foraging, a long-term temporal memory did not provide a clear benefit over a simple short-term memory that keeps track of the current resource availability. Long-term temporal memories may therefore have emerged in contexts where short-term temporal cognition is useless, i.e. when the anticipation of future environmental changes is strongly needed.

scholarly journals The short and long-term implications of warming and increased sea water pCO2 on the physiological response of a temperate neogastropod species

2021 ◽  
Vol 169 (1) ◽  
Author(s):  
Maria Loreto Mardones ◽  
Sven Thatje ◽  
Phillip B. Fenberg ◽  
Chris Hauton
Keyword(s):  
Atmospheric Carbon Dioxide ◽  
Environmental Changes ◽  
Sea Water ◽  
Molecular Response ◽  
Rocky Shores ◽  
Long Term Effects ◽  
Short Term ◽  
Consumption Rates ◽  
Short And Long Term

AbstractGlobal average temperatures and seawater pCO2 have rapidly increased due to the oceanic uptake of atmospheric carbon dioxide producing severe consequences for a broad range of species. The impacts on marine ectotherms have been largely reported at short-term scales (i.e. from days to weeks); however, the prolonged effects on long-term processes such as reproduction have received little attention. The gastropod Ocenebra erinaceus is a key predator structuring communities on rocky shores of the French and UK coasts. Even though rocky shore species are regarded as being very tolerant to changes in temperature and pH, many of them are living near their upper tolerance limits, making them susceptible to rapid environmental changes. Here, we report that future mean seawater conditions (RCP8.5, + 3 °C and ~ 900 μatm CO2) do not significantly affect the physiology and molecular response of O. erinaceus adults after 132 days. During the first 50 days, there was a slight impact on oxygen consumption rates and body weight; however, after 95 days of exposure, gastropods fully acclimated to the experimental condition. Despite this, reproduction in females exposed to these future seawater conditions ceased after long-term exposure (~ 10 months). Therefore, in the short-term, O. erinaceus appear to be capable of full compensation; however, in the long-term, they fail to invest in reproduction. We conclude studies should be based on combined results from both short- and long-term effects, to present realistic projections of the ecological consequences of climate warming.

Pine forest lichens under eutrophication generated by a great cormorant colony

2014 ◽  
Vol 46 (2) ◽  
pp. 213-228 ◽  
Author(s):  
Jurga MOTIEJŪNAITĖ ◽  
Reda IRŠĖNAITĖ ◽  
Gražina ADAMONYTĖ ◽  
Mindaugas DAGYS ◽  
Ričardas TARAŠKEVIČIUS ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Transitional Zone ◽  
Pine Forest ◽  
Great Cormorant ◽  
Nest Density ◽  
Phalacrocorax Carbo ◽  
Short Term ◽  
Lichen Community ◽  
The Impact

AbstractLichen community changes were investigated on trees within a colony of great cormorants (Phalacrocorax carbo sinensis) established in a pine forest on the Curonian Spit, western Lithuania. The impact of birds on the forest has altered the number and characteristics of substrata available to lichens. The lowest number of lichen species and occurrences was registered on trees in the most active part of the colony with the highest nest density. Lichen community patterns were most strongly related to P and Ca content in substrata and pH values. Some acidophytic species showed negative correlations, both with long-term and short-term ornithogenic influence. However, three acidophytes (Chaenotheca ferruginea, Lepraria incana, Coenogonium pineti) demonstrated an affinity for the transitional zone and recently occupied trees, and furthermore,C. pinetiapparently reacted positively to a short-term ornithogenic influence but negatively to a long-term one. These three lichens, along with algae, were the main, and often the only, components of epiphytic communities on trees at the edge of the colony and apparently indicated the crucial point of the acidophytic community under the increasing load of nutrients. All nitrophytic species showed an affinity for a long-term bird influence and reacted negatively to a short-term influence. Only free-living algae (predominating speciesDesmococcus olivaceus) showed a clear affinity for trees occupied by bird nests.Hypogymnia physodeswas found to be an indicator for early environmental changes following eutrophication. The study also showed that high concentrations of P did not have a mitigating effect on the detrimental impact brought about by increases in N and pH levels, but was possibly equally detrimental to acidophytic lichens.

Environmental Changes During the Past 2000 Years in North-Central Wisconsin: Analysis of Pollen, Charcoal, and Seeds from Varved Lake Sediments

1978 ◽  
Vol 10 (1) ◽  
pp. 55-68 ◽  
Author(s):  
Albert M. Swain
Keyword(s):  
General Circulation ◽  
Environmental Changes ◽  
Wave Pattern ◽  
Pollen Record ◽  
Short Term ◽  
North Central ◽  
The Past ◽  
Past 2000 Years ◽  
Long Term Changes

A 2000-year accumulation of varved sediments from Hell's Kitchen Lake in north-central Wisconsin was analyzed for pollen, charcoal, and seeds. The varves provided an accurate time scale for the study. The pollen record indicates changes on two different time scales. Short-term changes lasting several decades appear to be superimposed on long-term changes lasting several centuries. The short-term changes are related to individual fires, and the long-term changes result from increases or decreases in the frequency of these perturbations. From 2000 to 1150 years ago the average interval between fires was about 100 years, and from 1150 to 120 years ago the interval increased to about 140 years. Evidence from pollen, seeds, and charcoal at Hell's Kitchen Lake suggests that at least two “moist” intervals occurred during the past 2000 years, one between 2000 and 1700 years ago and the other between 600 and 100 years ago. A third but minor “moist” period occurred about 1150 to 850 years ago. A pollen and seed diagram shows that these intervals are characterized by increased percentages of white pine pollen, hemlock pollen, and yellow birch seeds, and by decreased levels of charcoal. The “dry” interval of 1700 to 1150 years ago is characterized by increased percentages of paper birch seeds, oak pollen, and aspen pollen, along with high levels of charcoal. The times of climatic change indicated at Hell's Kitchen Lake are nearly synchronous with those based on studies of tree rings, soils, glacial activity, and other pollen studies from various regions of North America, but the direction of these inferred changes is not always the same. This result suggests that the long-wave pattern of the general circulation has been variable during the past 2000 years.

scholarly journals Antagonistic effects of long- and short-term environmental variation on species coexistence

2021 ◽  
Vol 288 (1958) ◽  
pp. 20211491
Author(s):  
Ming Liu ◽  
Dustin R. Rubenstein ◽  
Siew Ann Cheong ◽  
Sheng-Feng Shen
Keyword(s):  
Species Coexistence ◽  
Environmental Changes ◽  
Environmental Variation ◽  
Ecological Impacts ◽  
Short Term ◽  
Term Variation ◽  
Environmental Fluctuations ◽  
Time Periods ◽  
The Impact

Assessing the impact of environmental fluctuations on species coexistence is critical for understanding biodiversity loss and the ecological impacts of climate change. Yet determining how properties like the intensity, frequency or duration of environmental fluctuations influence species coexistence remains challenging, presumably because previous studies have focused on indefinite coexistence. Here, we model the impact of environmental fluctuations at different temporal scales on species coexistence over a finite time period by employing the concepts of time-windowed averaging and performance curves to incorporate temporal niche differences within a stochastic Lotka–Volterra model. We discover that short- and long-term environmental variability has contrasting effects on transient species coexistence, such that short-term variation favours species coexistence, whereas long-term variation promotes competitive exclusion. This dichotomy occurs because small samples (e.g. environmental changes over long time periods) are more likely to show large deviations from the expected mean and are more difficult to predict than large samples (e.g. environmental changes over short time periods), as described in the central limit theorem. Consequently, we show that the complex set of relationships among environmental fluctuations and species coexistence found in previous studies can all be synthesized within a general framework by explicitly considering both long- and short-term environmental variation.

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