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Preventing crop raiding by the Vulnerable common hippopotamus Hippopotamus amphibius in Guinea-Bissau

Published online by Cambridge University Press:  26 January 2016

Luis M. González*
Affiliation:
Subdirección General de Medio Natural, Ministerio de Medio Ambiente, Plaza San Juan de la Cruz s/n, Madrid 28071, Spain
Francisco G. D. Montoto
Affiliation:
Subdirección General de Medio Natural, Ministerio de Medio Ambiente, Plaza San Juan de la Cruz s/n, Madrid 28071, Spain
Tome Mereck
Affiliation:
Fundación CBD-Hábitat, Madrid, Spain
Junior Alves
Affiliation:
Fundación CBD-Hábitat, Madrid, Spain
José Pereira
Affiliation:
Fundación CBD-Hábitat, Madrid, Spain
Pablo Fernández de Larrinoa
Affiliation:
Fundación CBD-Hábitat, Madrid, Spain
Ana Maroto
Affiliation:
Fundación CBD-Hábitat, Madrid, Spain
Luis Bolonio
Affiliation:
Fundación CBD-Hábitat, Madrid, Spain
Nuria El-Kadhir
Affiliation:
Fundación CBD-Hábitat, Madrid, Spain
*
(Corresponding author) E-mail lmgonzalez@magrama.es
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Abstract

Guinea-Bissau is host to the westernmost subpopulation of the common hippopotamus Hippopotamus amphibius, which is one of only two known populations inhabiting coastal waters. The presence of hippopotamuses causes conflict with rice farmers as a result of crop damage and the absence of effective measures to protect crops. To develop an effective method for protecting rice fields, we studied the patterns of access to flooded and rain-fed rice fields by hippopotamuses and assessed the effect of the installation of electric fences. Hippopotamuses were detected in 54% of the flooded fields (n = 100) and in 31.9% of the rain-fed fields (n = 91). They were detected more frequently in fields on offshore islands than on the mainland, in unfenced than in fenced fields, and in fields closer to running water. Hippopotamuses entered fenced flooded fields less frequently than unfenced, and were detected most frequently at the end of the rainy season and the start of the dry season, and in the period of vegetative stem growth. Electric fences were an effective deterrent and facilitated increased rice production. The maintenance and cost of the electric fencing were acceptable to farmers, and therefore the use of such fencing is recommended to resolve the conflict between hippopotamuses and farmers in Guinea-Bissau and in other areas with similar conditions.

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Copyright © Fauna & Flora International 2016 
Figure 0

Fig. 1 Locations of the rice fields (black filled circles) studied in Cacheu Natural Park, Bissorao and Carantaba, on mainland Guinea-Bissau, and in the Orango Islands National Park and Uno Island, with the hippopotamus Hippopotamus amphibius resting places (filled white circles) identified in previous studies (Silva, 2008).

Figure 1

Table 1 Numbers of fenced and unfenced rice fields (flooded and rain-fed) studied in the Orango Islands National Park and Uno Island during 2008−2011, and on mainland Guinea-Bissau during 2012−2013 (Fig. 1).

Figure 2

Plate 1 The electric fencing system in a flooded rice field in Orango (Fig. 1), with the energizer unit model S250 with integrated solar panel.

Figure 3

Fig. 2 Mean number of flooded rice fields (with 95% confidence intervals) in the study areas in Guinea-Bissau (Fig. 1) where hippopotamuses were detected at various periods before, during and after the rainy season.

Figure 4

Fig. 3 Mean number of flooded rice fields (with 95% confidence intervals) in the study areas in Guinea-Bissau (Fig. 1) where hippopotamuses were detected during various stages of crop development.

Figure 5

Plate 2 A hippopotamus Hippopotamus amphibius feeding in a flooded rice field in Carantaba, observed by local people. (Photograph by Tete Sambu, 2011)

Figure 6

Plate 3 Camera trap images of a hippopotamus crossing an electric fence in a rice field in Acagume (Orango), in 2009.