Population size and structure of the Nile crocodile Crocodylus niloticus in the lower Zambezi valley

Abstract

Concern has been raised about the lack of population data for the Nile crocodile Crocodylus niloticus in the lower/middle Zambezi valley. This area is important for conservation as well as being a source of crocodile eggs and adults for the ranching industry. Two spotlight surveys, in 2006 and 2009, were used to estimate population size, structure and trends. A stage-structured matrix model was parameterized from existing literature and the expected predictions were compared to those observed. The survey data suggests a population increase since 2006. Crocodile density was greatest (3.1 km −1 ) in the areas of increased wildlife and habitat protection and lowest (1.4 km −1 ) in areas of increased human presence. The predicted population stage structure differed to that observed, suggestive of a population not at equilibrium. Data on offtakes of crocodile eggs and adults would be useful for examining why this is the case. Continued monitoring of the wild population is necessary, to evaluate the trend of an increasing crocodile population, and additional demographic data for modelling purposes would be desirable. This paper contains supplementary material that can be found online at

Stage-based model of population dynamics and harvest of Broad-snouted caiman (<i>Caiman latirostris<i>) under different management scenarios

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Impact of Anthropogenic Activities on the Abundance of &lt;i&gt;Crocodylus suchus&lt;/i&gt; (Saint-Hilaire 1807) within the Nazinga Game Ranch, Burkina Faso

“…This reflects the fact that crocodiles need quiet areas. This demonstrates the positive influence of protected areas for conservation of this crocodile [32]. GLM analysis showed a correlation between different environmental factors.…”

Negative human–crocodile interactions in Kariba, Zimbabwe: data to support potential mitigation strategies

“…The Nile crocodile is a keystone species in the Lake Kariba area and a decline in its population could result in cascading negative effects on the ecosystem (Botha et al, 2011; van der Ploeg et al, 2011; Sai et al, 2016). In addition to their ecological role, crocodiles also have economic value through ecotourism (Wallace et al, 2013); their conservation therefore benefits the local economy as well as supporting vital ecosystem functions.…”