scholarly journals Necromys lasiurus: Lessons From a 38-Year Study in an Amazonian Savanna

2021 ◽  
Vol 9 ◽  
Author(s):  
Clarisa Alves Rosa ◽  
Pedro Henrique Salomão Ganança ◽  
Albertina Pimentel Lima ◽  
William Ernest Magnusson
Keyword(s):  
Population Dynamics ◽  
Global Climate ◽  
Regional Scale ◽  
Local Scale ◽  
Population Fluctuations ◽  
Plant Interactions ◽  
Seed Disperser ◽  
Mammal Fauna ◽  
Long Term Studies

Amazonian savannas are isolated patches of open habitats within an array of extensive tropical forest. The mammal fauna of the savannas in the Alter do Chão region (Santarém Municipality), is dominated by Necromys lasiurus, whose populations have been studied by researchers of the National Institute of Amazonian Research since 1983. Here, we summarize the studies and advances made so far to better understand aspects related to population dynamics and ecology of savanna rodents and the strategies they use to persist in an environment with frequent fires subject to global climatic influences. In the Amazonian savannas the species acts as a seed disperser and population fluctuations are related to invertebrate availability, but not with fire or vegetation structure. Global climate appears to affect N. lasiurus population dynamics at local scale (i.e., plot scale) but not at the regional scale of the Alter do Chão savannas. The long-term studies in Alter do Chão generated many advances about Necromys lasiurus population dynamics and ecology, including aspects relating to feeding, home range, animal-plant interactions, the effects of fire and climate change.

scholarly journals Climatic Factors, Reproductive Success and Population Dynamics in the Montane Vole Microtus Montanus

2005 ◽  
Vol 29 ◽  
pp. 49-51
Author(s):  
Alita Pinter
Keyword(s):  
Population Dynamics ◽  
Reproductive Success ◽  
Population Density ◽  
Climatic Factors ◽  
Small Rodents ◽  
Microtus Montanus ◽  
Small Measure ◽  
Long Term Studies

A variety of hypotheses has been proposed to explain multiannual fluctuations in population density ("cycles") of small rodents (for reviews see Finerty 1980, Taitt and Krebs 1985). Doubtless, such cycles - known since antiquity (Elton 1942) - result from an interaction of a multitude of factors. However, the inability of extant hypotheses, alone or in combination, to explain the causality of cycles rests in no small measure with the fact that long-term studies of the phenomenon are notoriously uncommon.

scholarly journals Are snake populations in widespread decline?

2010 ◽  
Vol 6 (6) ◽  
pp. 777-780 ◽  
Author(s):  
C. J. Reading ◽  
L. M. Luiselli ◽  
G. C. Akani ◽  
X. Bonnet ◽  
G. Amori ◽  
...  
Keyword(s):  
Global Climate Change ◽  
Prey Availability ◽  
Global Climate ◽  
Population Declines ◽  
Common Cause ◽  
Top Predators ◽  
Short Period ◽  
The Uk ◽  
Long Term Studies

Long-term studies have revealed population declines in fishes, amphibians, reptiles, birds and mammals. In birds, and particularly amphibians, these declines are a global phenomenon whose causes are often unclear. Among reptiles, snakes are top predators and therefore a decline in their numbers may have serious consequences for the functioning of many ecosystems. Our results show that, of 17 snake populations (eight species) from the UK, France, Italy, Nigeria and Australia, 11 have declined sharply over the same relatively short period of time with five remaining stable and one showing signs of a marginal increase. Although the causes of these declines are currently unknown, we suspect that they are multi-faceted (such as habitat quality deterioration, prey availability), and with a common cause, e.g. global climate change, at their root.

scholarly journals A comprehensive history of climate and habitat stability of the last 800&thinsp,000 years

2019 ◽  
Author(s):  
Mario Krapp ◽  
Robert Beyer ◽  
Stephen L. Edmundson ◽  
Paul J. Valdes ◽  
Andrea Manica
Keyword(s):  
Climate Model ◽  
Temporal Dynamics ◽  
Global Climate ◽  
Global Climate Model ◽  
Regional Scale ◽  
Geological Time ◽  
Comprehensive Overview ◽  
Long Term Stability ◽  
History Of

Abstract. A detailed and accurate reconstruction of the past climate is essential in understanding the interactions between ecosystems and their environment through time. We know that climatic drivers have shaped the distribution and evolution of species, including our own, and their habitats. Yet, spatially-detailed climate reconstructions that continuously cover the Quaternary do not exist. This is mainly because no paleoclimate model can reconstruct regional-scale dynamics over geological time scales. Here we develop a statistical emulator, the Global Climate Model Emulator (GCMET), which reconstructs the climate of the last 800 000 years with unprecedented spatial detail. GCMET captures the temporal dynamics of glacial-interglacial climates as an Earth System Model of Intermediate Complexity would whilst resolving the local dynamics with the accuracy of a Global Climate Model. It provides a new, unique resource to explore the climate of the Quaternary, which we use to investigate the long-term stability of major habitat types. We identify a number of stable pockets of habitat that have remained unchanged over the last 800 thousand years, acting as potential long-term evolutionary refugia. Thus, the highly detailed, comprehensive overview of climatic changes through time delivered by GCMET provides the needed resolution to quantify the role of long term habitat change and fragmentation in an ecological and anthropological context.

scholarly journals Quantifying whether different demographic models produce incongruent results on population dynamics of two long-term studied rodent species

2017 ◽  
Vol 3 (1) ◽  
pp. 18-26
Author(s):  
Giovanni Amori ◽  
Valentina De Silvestro ◽  
Paolo Ciucci ◽  
Luca Luiselli
Keyword(s):  
Population Dynamics ◽  
Population Density ◽  
Population Size ◽  
Myodes Glareolus ◽  
Suitable Model ◽  
Demographic Model ◽  
Apodemus Flavicollis ◽  
Demographic Models ◽  
Long Term Studies

Abstract1. Population density (ind/ha) of long-term (>15 years) series of CMR populations, using distinct demographic models designed for both open and closed populations, were analysed for two sympatric species of rodents (Myodes glareolus and Apodemus flavicollis) from a mountain area in central Italy, in order to test the relative performance of various employed demographic models. In particular, the hypothesis that enumeration models systematically underestimate the population size of a given population was tested.2. Overall, we compared the performance of 7 distinct demographic models, including both closed and open models, for each study species. Although the two species revealed remarkable intrinsic differences in demography traits (for instance, a lower propensity for being recaptured in Apodemus flavicollis), the Robust Design appeared to be the best fitting model, showing that it is the most suitable model for long-term studies.3. Among the various analysed demographic models, Jolly-Seber returned the lower estimates of population density for both species. Thus, this demographic model could not be suggested for being applied for long-term studies of small mammal populations because it tends to remarkably underestimate the effective population size. Nonetheless, yearly estimates of population density by Jolly-Seber correlated positively with yearly estimates of population density by closed population models, thus showing that interannual trends in population dynamics were uncovered by both types of demographic models, although with different values in terms of true population size.

scholarly journals Climatic Factors, Reproductive Success and Population Dynamics in the Montane Vole, Microtus montanus

1997 ◽  
Vol 21 ◽  
pp. 57-59
Author(s):  
Aelita Pinter
Keyword(s):  
Population Dynamics ◽  
Population Density ◽  
National Park ◽  
Climatic Factors ◽  
Term Study ◽  
Microtus Montanus ◽  
Long Term Study ◽  
Small Measure ◽  
Long Term Studies

Multiannual fluctuations ("cycles") in population density of small rodents doubtless result from the interaction of a multitude of factors, as evidenced by the variety of hypotheses proposed to explain the phenomenon (for reviews see Finerty 1980, Taitt and Krebs 1985). However, the inability of these hypotheses - alone or in combination - to explain the causality of cycles rests in no small measure with the fact that long-term studies of the phenomenon are notoriously uncommon. The objectives of this project are to continue a long-term study of the population dynamics of the montane vole, Microtus montanus, in Grand Teton National Park. On the basis of earlier observations (Pinter 1986, 1988) particular emphasis will be placed on how environmental variables, possibly acting through reproductive responses, contribute to the population density cycles of these rodents.

scholarly journals Climatic Factors, Reproductive Success and Population Dynamics in the Montane Vole, Microtus montanus.

2003 ◽  
Vol 27 ◽  
pp. 42-44
Author(s):  
Aelita Pinter
Keyword(s):  
Population Dynamics ◽  
Population Density ◽  
National Park ◽  
Climatic Factors ◽  
Term Study ◽  
Microtus Montanus ◽  
Long Term Study ◽  
Small Measure ◽  
Long Term Studies

A variety of hypotheses have been proposed to explain multiannual fluctuations in population density ("cycles") of small rodents (for reviews see Finerty 1980, Taitt and Krebs 1985). Doubtless, such cycles - known since antiquity (Elton 1942) - result from an interaction of a multitude of factors. However, the inability of extant hypotheses, alone or in combination, to explain the causality of cycles rests in no small measure with the fact that long-term studies of the phenomenon are notoriously uncommon. The objectives of this project are to continue the long-term study of population dynamics of the montane vole, Microtus montanus, in Grand Teton National Park. Earlier observations (Pinter 1986, 1988) indicate that environmental variables might contribute to the population density cycles of these rodents, possibly by influencing their growth and various aspects of their reproduction.

scholarly journals Long-term changes in the species and functional diversity of a fine sand macrobenthic community in the English Channel

2018 ◽  
Author(s):  
Lise Bacouillard ◽  
Noémie Baux ◽  
Jean-Claude Dauvin ◽  
Nicolas Desroy ◽  
Katja Juliana Geiger ◽  
...  
Keyword(s):  
Community Structure ◽  
Functional Diversity ◽  
Regional Scale ◽  
Monitoring Program ◽  
Diversity Indices ◽  
Population Fluctuations ◽  
Α Diversity ◽  
Long Term Changes ◽  
Functional Diversity Indices

In the eastern Bay of Seine, which is a representative area of coastal zones exposed to numerous anthropogenic disturbances, data from a long-term monitoring program of the benthic macrofauna based on a framework of 60 stations sampled during 7 cruises from 1988 to 2016 were used to investigate the link between species and functional diversity at different scales and assess how long-term changes in the community structure may have altered the ecosystem functioning. To cover the different facets of α-diversity, a selection of species and functional diversity indices were calculated and the links between these metrics were determined from a Principal Component Analysis. The β-diversity was analysed by applying multivariate methods on both species and traits composition matrices. Population fluctuations of a few very abundant species led to the major variations observed in the structure of the community in both taxonomic and functional aspects. A certain redundancy was found among species and functional diversity indices in terms of richness, evenness and heterogeneity. Likewise, at regional scale, similar patterns were reported on the spatial structure of the community in terms of species and trait composition. These patterns persist over time suggesting that the community structure and its functioning are rather resilient.

scholarly journals Diets of Overwintering Caribou, Rangifer tarandus, Track Decadal Changes in Arctic Tundra Vegetation

2007 ◽  
Vol 121 (4) ◽  
pp. 379 ◽  
Author(s):  
Kyle Joly ◽  
M. Jeanie Cole ◽  
Randi R. Jandt
Keyword(s):  
Population Dynamics ◽  
Global Warming ◽  
Rangifer Tarandus ◽  
Arctic Ecosystems ◽  
Fecal Analysis ◽  
Tundra Vegetation ◽  
Western Arctic ◽  
Winter Diets ◽  
Long Term Studies

We compared winter diets of Western Arctic Herd Caribou (Rangifer tarandus) from 1995/1996 and 2005 using microhistological fecal analysis on samples collected at paired permanent vegetation transects. Changes in the diets of Caribou followed the same trends as vegetative changes documented in long-term studies in northwestern Alaska. Lichens were significantly less prevalent on the landscape and in the winter diets of Caribou between 1995/1996 and 2005, while graminoids (grasses and sedges) were significantly more prevalent. Dramatic changes are forecasted for Arctic ecosystems under global warming scenarios which may continue the trend of declining lichens in northwestern Alaska and in the diet of Western Arctic Herd Caribou. The question of whether or not the altered diet will affect the population dynamics of this herd remains unresolved.

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