Influence of increasing dryness, animal feeding strategy and human hunting on large ungulates abundance: A first approach in West Africa

Abstract

Large ungulates as primary consumers consume variable proportions of herbaceous and woody plants. Recent climate changes modify the herbaceous/woody plant balance. To test their differential effects on ungulate species abundance, we compared large ungulate feeding strategies with climate change patterns, taking the game preferences of local people into account. We analyzed changes in population density of ten species of large ungulates between two census periods (1990-1993 and 1994-1998) in the Niokolo Koba National Park, Senegal. We calculated the cumulative precipitation deficit during the 1989-1997 period. Additionally, we conducted an extensive survey of local people's game preferences. Results are: 1-in the period 1989-98 all but one year have been drier than the 1940-98 average; 2-this has a cumulative effect on the dryness of the land i.e. produces a water deficit; 3-this pattern favors the growth of woody plants over herbaceous ones; 4-this favors browsers over grazers; 5-grazers are generally preferred by hunters; 6grazers are therefore disadvantaged both by the drier climate and by preferential hunting; 7-management in the National Park should focus on holding back bush encroachment and encouraging the growth of herba ceous plants.

A citizen science approach to monitoring of the Lion Panthera leo (Carnivora: Felidae) population in Niokolo-Koba National Park, Senegal

“…shown in Table 3. The mean annual rainfall estimated for the study zone by this method (975 mm) falls in the range of 900-1,200 mm in NKNP given by Galat et al (2015). When the rainfall data are offset for display purposes as the annual rainfall deficiency relative to the average rainfall in the period 2014-2018, the correlation between the number of lion observations each year and rainfall deficiency of the previous year seems evident (see Figure 3).…”

“…97% of the lion observations (90 out of the 93) were within this area, while three additional incidental observations were made between 16 and 22 km to the east of the study area on the national highway traversing the Park. Galat et al (2015) and Tiomoko & Van Merm (2015) describe the main physical and biological characteristics of NKNP which are summarised below with particular reference to the study area.…”

“…Since 2007, however, NKNP has been listed as a world heritage site in danger. Poaching, incursion of livestock and illegal mining are among the factors that have contributed to this situation, which has resulted in dramatic decreases in the populations of megafauna in the Park (Renaud et al 2006;Galat et al 2015;UNESCO 2019). Henschel et al (2014) estimated that in 2011 there were a maximum of 54 lions in the Park and stated that the population was small and appeared to be declining.…”

“…Another hypothesis implying the opposite effect of rainfall on lion observations is that low rainfall might reduce prey populations and thus lion numbers in the following dry season due to environmental stress on the prey, a factor that has been proposed to operate in NKNP over medium-term periods (Galat et al 2015). There is, however, no evidence that such a mechanism could operate over periods as short as one year.…”