Influence des perturbations anthropiques sur les communautés de petits  mammifères des savanes gabonaises

Les savanes gabonaises connaissent des feux anthropiques récurrents, entraînant des dommages sur cet écosystème. L’influence de ce facteur sur la diversité des micromammifères n’a jamais été étudiée. Une situation préoccupante pour ce taxon qui fait l’objet de très peu de programmes de protection. A travers l’analyse de la distribution spatiale des espèces (Muridés), l’étude vise à mesurer l’empreinte écologique des activités anthropiques dans trois régions du Gabon, présentant des niveaux de perturbations différents. Au total 259 individus appartenant à six espèces de muridés ont été capturés avec un effort de 6220 nuit-pièges. Les rendements de capture varient de 0,5 à 15%. Mus minutoides (62,5%) et Lemniscomys striatus (28.9%) sont les plus abondantes. La richesse spécifique (S) varie de 1 à 4 espèces dans les savanes post -feu, alors qu’elle est de 5 dans les savanes protégées des feux, et de 2 espèces dans les savanes fauchées puis brulées. La diversité la plus élevée a été observée dans les savanes non exposées au feu (H’= 1,10 ; J= 0,68). Ceci atteste que le feu influe sur l’abondance, et lorsqu’il est préalablement associé à la fauche, il agirait à la fois sur la diversité et sur l’abondance d’espèces locales. English title: Influence of human disturbance to the small mammal communities in the Gabonese savannahs In the issue of the use of recurrent fires in Gabon, we carried out an inventory both in the Gabonese savannahs that are regularly burned and in those that are not. The study was carried out in the southern and central savannahs of Gabon during the periods from 2004, 2012 and 2013. A total of 259 individuals representing six species of small savannah rodents were captured over 6,220 trap nights. Trap success was variable (0.5 to 15%). Mus minutoides (62.5%) and Lemniscomys striatus (28.9%) are the most abundant. Small rodent abundance was significantly higher in the savannahs protected from fires. The species richness varies from 1 to 4 species in the post-fire savannahs and up to 5 species in the savannahs protected from fires. The savannahs that were mowing prior to burning have yielded only 2 species. The highest diversity index (H’) is found in savannahs not exposed to fire (H’= 1.10). Bush fires seem to have a direct effect on species abundance. Conversely, when savannahs are mown prior to burning, both the diversity and abundance of local species communities are affected. This study gave an initial idea of the diversity of the rodent population in this the recurrent use to fires.

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Dynamics of small-mammal communities along an elevational gradient

Canadian Journal of Zoology ◽

10.1139/cjz-2018-0201 ◽

2019 ◽

Vol 97 (4) ◽

pp. 312-318 ◽

Cited By ~ 1

Author(s):

A.M. Benedek ◽

I. Sîrbu

Keyword(s):

Small Mammal ◽

Temporal Dynamics ◽

Species Abundance ◽

Elevational Gradient ◽

Myodes Glareolus ◽

Small Areas ◽

Live Trapping ◽

Small Mammal Communities ◽

Mammal Communities ◽

Bank Vole Myodes Glareolus

Elevation is one of the most important natural gradients that is strongly shaping communities across relatively small areas. However, few studies have followed the temporal dynamics of elevational patterns, even in organisms for which population and community fluctuations have been extensively studied, such as rodents. Here we report the multiannual dynamics of small-mammal communities along an elevational gradient in the Southern Carpathians. During a 5-year survey, we conducted live-trapping in forested and shrubby habitats, at elevations between 820 and 2040 m. We used partial constrained multivariate analysis and mixed-effects models to test the effect of elevation, year, and their interaction. Community metrics differed significantly between even and odd years and temporal changes had stronger effect on small-mammal communities than elevation. The 2-year pattern of dynamics was especially marked in the yellow-necked field mouse (Apodemus flavicollis (Melchior, 1834)). Species abundance was predicted not only by year and elevation, but also by their interaction. The dominant rodent species, the bank vole (Myodes glareolus (Schreber, 1780)) and A. flavicollis, showed opposite annual patterns in relation to elevation, possibly as a strategy to avoid competition. Failure to consider the fluctuations in montane small-mammal communities may lead to wrong assessment of species’ state and distribution.

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Ecological similarity explains species abundance distribution of small mammal communities

Acta Oecologica ◽

10.1016/j.actao.2019.103502 ◽

2020 ◽

Vol 102 ◽

pp. 103502

Author(s):

José Hidasi-Neto ◽

Luis Mauricio Bini ◽

Tadeu Siqueira ◽

Marcus Vinicius Cianciaruso

Keyword(s):

Small Mammal ◽

Species Abundance ◽

Species Abundance Distribution ◽

Abundance Distribution ◽

Small Mammal Communities ◽

Mammal Communities

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Spatial variation of small mammal communities in northwestern Argentina

Mammalia ◽

10.1515/mammalia-2020-0149 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Sofía d’ Hiriart ◽

Gerardo Cueto ◽

Pablo E. Ortiz ◽

Pablo Teta ◽

J. Pablo Jayat

Keyword(s):

Small Mammal ◽

Large Scale ◽

Regional Scale ◽

Species Abundance ◽

Combined Effect ◽

Species Variation ◽

Mammal Species ◽

Northwestern Argentina ◽

Small Mammal Communities ◽

Mammal Communities

Abstract Northwestern Argentina (NWA) is a region characterized by a complex geomorphology, and encompasses six ecoregions in a relatively small area. The environmental heterogeneity of NWA and the sensitivity of small mammals towards environmental and landscape changes constitute a good scenario to assess the factors that influence small mammal diversity patterns in the region. We studied small mammal communities obtained from pellet samples in 24 localities of NWA. We identified 50 non-volant small mammal species and obtained topographic, climate and land cover variables. Our results show that small mammal communities respond to environmental factors at a regional scale. Such variations were explained in different proportions by the geographic position of the collecting sites, landscape and climate. Furthermore, the combined effect of these factors was the main determinant of species abundance patterns. Our results support the need of large-scale approaches to study communities, since the explanations of the observed patterns are simpler and more general. We emphasize the importance of considering the combined effect of different environmental predictors, which allows determining the amount of species variation that is spatially structured, and within that, the amount of variation related to the influence of the measured environmental variables.

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The influence of spring floods on small mammal communities in the Nemunas River Delta, Lithuania

Biologia ◽

10.2478/s11756-012-0116-8 ◽

2012 ◽

Vol 67 (6) ◽

Cited By ~ 6

Author(s):

Linas Balčiauskas ◽

Laima Balčiauskienė ◽

Agnė Janonytė

Keyword(s):

Small Mammals ◽

Small Mammal ◽

Diversity Index ◽

River Delta ◽

Negative Effects ◽

Mammal Species ◽

Environmental Agents ◽

Small Mammal Communities ◽

High Flood ◽

Mammal Communities

AbstractThe influence of the annual spring floods on small mammal communities was studied in the Nemunas River Delta, SW Lithuania. The aim of the investigation was to compare the diversity of small mammals inhabiting spring-flooded meadows, meadows not subjected to flooding and spring-flooded forest in years characterized by differing heights and durations of spring flood. In the years of the high flood, the number of species and diversity index were higher, while index of dominance was less than in the years of low flood. Significantly, the highest proportions of Apodemus agrarius were recorded in spring-flooded meadows in years of high flood (41.7%), while Microtus oeconomus occurred in the highest proportions in spring-flooded meadows in years of low flood (66.8%) and in meadows not subjected to flooding (47.1%). In non-flooded areas, M. Oeconomus is not expelled by the floods and outcompetes other species. After high levels of flooding, during the process of re-population, the voles may be outcompeted by A. agrarius. In the absence of dominant species, greater opportunities existed for the establishment of more species (13 species in flooded meadows). Micromys minutus accounted for up to 19.5–30.1% in the years of high flood. We concluded that the annual spring floods in the Nemunas Delta had no long-term negative effects, the number of small mammal species and their abundance had been restored in just a few months. The worst consequences of the high flood were recorded in forest habitat. Spring floods, and especially the higher floods, are natural environmental agents, maintaining the high diversity of small mammals in meadows and reed-beds.

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Small rodent cycles influence interactions among predators in a boreal forest ecosystem

Mammal Research ◽

10.1007/s13364-021-00590-7 ◽

2021 ◽

Vol 66 (4) ◽

pp. 583-593

Author(s):

Rocío Cano-Martínez ◽

David Carricondo-Sanchez ◽

Olivier Devineau ◽

Morten Odden

Keyword(s):

Structural Equation ◽

Agricultural Land ◽

Structural Equation Models ◽

Red Fox ◽

Interspecific Interactions ◽

Small Rodent ◽

Generalist Predator ◽

Pine Marten ◽

Mustela Nivalis ◽

Rodent Abundance

AbstractCyclic fluctuations of prey have profound effects on the functioning of ecosystems, for example, by changing the dynamics, behavior, and intraguild interactions of predators. The aim of this study was to assess the effect of rodent cyclic fluctuations in the interspecific interactions of a guild of small- and medium-sized predators: red fox (Vulpes vulpes), pine marten (Martes martes), and weasels (Mustela erminea and Mustela nivalis) in the boreal ecosystem. We analyzed eight years (2007–2014) of snow tracking data from southeastern Norway using structural equation models to assess hypothesized networks of causal relationships. Our results show that fluctuations in rodent abundance alter the strength of predator’s interactions, as well as the effect of determinant environmental variables. Pine marten and weasel abundances were positively associated with rodent population growth rate, but not red fox abundance. All predators were positively associated with each other; however, the association between red fox and the other predators weakened when rodents increased. Rodent fluctuations had variable effects on the habitat use of the predators. The presence of agricultural land was important for all predators, but this importance weakened for the mustelids as rodent abundance increased. We discuss the shifting role of interference and exploitative competition as possible mechanisms behind these patterns. Overall, we highlight the importance of accounting for the dynamics of prey resources when studying interspecific interactions among predators. Additionally, we demonstrate the importance of monitoring the predator populations in order to anticipate undesirable outcomes such as increased generalist predator abundances to the detriment of specialists.

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Population cycles and outbreaks of small rodents: ten essential questions we still need to solve

Oecologia ◽

10.1007/s00442-020-04810-w ◽

2020 ◽

Author(s):

Harry P. Andreassen ◽

Janne Sundell ◽

Fraucke Ecke ◽

Stefan Halle ◽

Marko Haapakoski ◽

...

Keyword(s):

Population Dynamics ◽

Large Amplitude ◽

Driving Forces ◽

Population Cycles ◽

Small Rodent ◽

Small Rodents ◽

Rodent Population ◽

The World ◽

Essential Questions ◽

Rodent Populations

AbstractMost small rodent populations in the world have fascinating population dynamics. In the northern hemisphere, voles and lemmings tend to show population cycles with regular fluctuations in numbers. In the southern hemisphere, small rodents tend to have large amplitude outbreaks with less regular intervals. In the light of vast research and debate over almost a century, we here discuss the driving forces of these different rodent population dynamics. We highlight ten questions directly related to the various characteristics of relevant populations and ecosystems that still need to be answered. This overview is not intended as a complete list of questions but rather focuses on the most important issues that are essential for understanding the generality of small rodent population dynamics.

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Small mammal communities in forest ecosystems affected by urbanization

Russian Journal of Ecology ◽

10.1134/s106741361405004x ◽

2014 ◽

Vol 45 (6) ◽

pp. 490-497 ◽

Cited By ~ 3

Author(s):

N. F. Chernousova ◽

O. V. Tolkach ◽

O. E. Dobrotvorskaya

Keyword(s):

Small Mammal ◽

Forest Ecosystems ◽

Small Mammal Communities ◽

Mammal Communities

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Small rodent communities (Muridae) in Gabonese savannas: species diversity and biogeographical affinities

Mammalia ◽

10.1515/mammalia-2020-0079 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Jean-François Mboumba ◽

Maxime R. Hervé ◽

Véronique Guyot ◽

Frederic Ysnel

Keyword(s):

Ecological Factors ◽

Abundant Species ◽

Small Rodent ◽

Small Rodents ◽

South West ◽

New Information ◽

Different Types ◽

Mus Minutoides ◽

Insight Into ◽

Coastal Basin

Abstract The study contributes to the knowledge of species composition and biogeographical affinities of savannas rodent in Gabon. Unlike small rodents in Gabonese forests, there is little data on the diversity of small rodents in Gabonese savannas. The diversity and distribution of rodent murid communities was studied in four different types of savanna in Gabon: Coastal Basin (South-West), Lopé/Okanda (in the Center), Batéké Plateaux (Southeastern) and Ngougnié/ N’yanga (in the South). A total of 428 individuals representing six species were captured over 11,920 trap nights. Trap success was highly variable (2.2–6.9 %). The most abundant species were Mus minutoides (69%) followed by Lemniscomys striatus (21.5%). Indices of species richness varied from 2 to 5 and diversity (Shannon and Weaver) was low in the four savannas with the highest value at Ngougnié/N’yanga (H′ = 1.2). Species distributions show that Gabonese savanna small rodents conform to four distribution types, with one species known from Zambesian savannas exhibiting austral affinities (Pelomys campanae: occurs in three southern savannas). This new information provides important insight into the biogeography of small rodents at a local and regional level. Moreover, the correspondence analysis highlighted an influence of local ecological factors on population abundance.

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