Demographic response of the Gambian Gerbil to seasonal changes in Savannah fallow fields
The Savannah gerbil, Gerbilliscus gambianus (Muridae: Gerbillinae) is important to the ecological relations of the dry grassland ecosystem of West Africa, as well as, being a zoonotic agent of human diseases and potential crop pest. We examined the impact of seasonal changes on the population dynami...
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doaj-d9ef758d8315475fbad92650e5a709662021-09-05T21:00:59ZengSciendoFolia Oecologica1338-70142019-05-014611910.2478/foecol-2019-0001foecol-2019-0001Demographic response of the Gambian Gerbil to seasonal changes in Savannah fallow fieldsRabiu Safianu0Rose Robert K.1Department of Biological Sciences, Old Dominion University, Norfolk, Virginia 23529-0266, USADepartment of Biological Sciences, Bayero University Kano, PMB 3011 Kano700241, NigeriaThe Savannah gerbil, Gerbilliscus gambianus (Muridae: Gerbillinae) is important to the ecological relations of the dry grassland ecosystem of West Africa, as well as, being a zoonotic agent of human diseases and potential crop pest. We examined the impact of seasonal changes on the population dynamics of G. gambianus in northern Nigeria, by completing population estimates using capture–mark–recapture (CMR) and indirect population density indices (PDI) methods. The latter included fecal pellet counts and limited spotlightening. During 1990–1992 we collected both CMR and PDI data, and established their relationship by regression, thus calibrating the PDI values to CMR estimator. We also completed a separate, PDI only, study during 2015–2017, and estimated monthly densities indirectly by toning the PDI values to population sizes in the CMR estimator. The lowest declines (<20 gerbils ha−1) were in mid rains (July–August), and highest increases (>90 gerbils ha−1) were after the rains (October–January). Seasonal effects on densities were significant during 1990–1992 but not during 2015–2017. There were improved survival rates for both adults (0.95) and young (0.83), adult capture probability (0.56), and mean monthly recruitment of young (23) after the rains. There was no significant change in the overall population dynamic pattern of G. gambianus over a 25-year period. Because G. gambianus did not maintain colonies inside farmlands cultivated by rain or irrigation, and its tendency for large population drops in mid-rains, we are in doubt of its potential as crop pest in northern Nigeria.https://doi.org/10.2478/foecol-2019-0001gerbilgrasslandpopulationrodentstropicalwest africa |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Rabiu Safianu Rose Robert K. |
spellingShingle |
Rabiu Safianu Rose Robert K. Demographic response of the Gambian Gerbil to seasonal changes in Savannah fallow fields Folia Oecologica gerbil grassland population rodents tropical west africa |
author_facet |
Rabiu Safianu Rose Robert K. |
author_sort |
Rabiu Safianu |
title |
Demographic response of the Gambian Gerbil to seasonal changes in Savannah fallow fields |
title_short |
Demographic response of the Gambian Gerbil to seasonal changes in Savannah fallow fields |
title_full |
Demographic response of the Gambian Gerbil to seasonal changes in Savannah fallow fields |
title_fullStr |
Demographic response of the Gambian Gerbil to seasonal changes in Savannah fallow fields |
title_full_unstemmed |
Demographic response of the Gambian Gerbil to seasonal changes in Savannah fallow fields |
title_sort |
demographic response of the gambian gerbil to seasonal changes in savannah fallow fields |
publisher |
Sciendo |
series |
Folia Oecologica |
issn |
1338-7014 |
publishDate |
2019-05-01 |
description |
The Savannah gerbil, Gerbilliscus gambianus (Muridae: Gerbillinae) is important to the ecological relations of the dry grassland ecosystem of West Africa, as well as, being a zoonotic agent of human diseases and potential crop pest. We examined the impact of seasonal changes on the population dynamics of G. gambianus in northern Nigeria, by completing population estimates using capture–mark–recapture (CMR) and indirect population density indices (PDI) methods. The latter included fecal pellet counts and limited spotlightening. During 1990–1992 we collected both CMR and PDI data, and established their relationship by regression, thus calibrating the PDI values to CMR estimator. We also completed a separate, PDI only, study during 2015–2017, and estimated monthly densities indirectly by toning the PDI values to population sizes in the CMR estimator. The lowest declines (<20 gerbils ha−1) were in mid rains (July–August), and highest increases (>90 gerbils ha−1) were after the rains (October–January). Seasonal effects on densities were significant during 1990–1992 but not during 2015–2017. There were improved survival rates for both adults (0.95) and young (0.83), adult capture probability (0.56), and mean monthly recruitment of young (23) after the rains. There was no significant change in the overall population dynamic pattern of G. gambianus over a 25-year period. Because G. gambianus did not maintain colonies inside farmlands cultivated by rain or irrigation, and its tendency for large population drops in mid-rains, we are in doubt of its potential as crop pest in northern Nigeria. |
topic |
gerbil grassland population rodents tropical west africa |
url |
https://doi.org/10.2478/foecol-2019-0001 |
work_keys_str_mv |
AT rabiusafianu demographicresponseofthegambiangerbiltoseasonalchangesinsavannahfallowfields AT roserobertk demographicresponseofthegambiangerbiltoseasonalchangesinsavannahfallowfields |
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