Effects of traditional pastoralism on grasshopper (Caelifera) assemblages in East Africa

Abstract

In East Africa, traditional pastoralists increase landscape heterogeneity by creating traditional livestock corrals (bomas). When these bomas are abandoned, they serve as long-term hot spots of increased nutrients and unique vegetation. However, the effect of bomas on insect populations is unclear. Grasshopper (Suborder Caelifera) assemblages are thought to reflect vegetation, and within Caelifera, the subfamily Oedipodinae is known to be associated with degraded areas. We sampled vegetation and collected grasshoppers inside of abandoned bomas, 50 m from abandoned bomas and 250 m from abandoned bomas. Bomas had significantly lower grass abundance than background vegetation. Total grasshopper abundance was positively correlated with grass and forb abundance, while the proportion of grasshoppers in the subfamily Oedipodinae was negatively correlated with grass abundance. Grasshopper abundance was significantly lower inside of bomas than outside of them, but the proportion of grasshoppers in the subfamily Oedipodinae was significantly higher inside of bomas than outside of them. This suggests that the decreased vegetation in abandoned bomas supports fewer grasshoppers, but a higher fraction of the grasshopper assemblage in abandoned bomas is composed of Oedipodinae. Thus, traditional pastoralists can have long-term effects on the size and composition of grasshopper assemblages through the use of bomas. R esum e En Afrique de l'Est, les eleveurs traditionnels augmentent l'h et erog en eit e des paysages en cr eant des enclos traditionnels (bomas) pour leur b etail. Lorsque ces bomas sont abandonn es, ils restent longtemps des lieux sp eciaux, plus riches en nutriments, o u la v eg etation est unique. Pourtant les effets des bomas sur les populations d'insectes ne sont pas clairs. L'on estime que les assemblages de sauterelles (du sousordre des Caelifera) refl etent la v eg etation et, parmi eux, la sous-famille des Oedipodinae est connue comme etant li ee aux endroits d egrad es. Nous avons collect e des echantillons de v eg etation et de sauterelles a l'int erieur de bomas abandonn es, a 50 m de l a et a 250 m. Les bomas pr esentaient des gramin ees en abondance de significativement plus faible que la v eg etation environnante. L'abondance totale des sauterelles etait positivement li ee a celle des gramin ees et des dicotyl edones, mais la proportion de sauterelles de la sousfamille des Oedipodinae etait li ee n egativementa celle des gramin ees. L'abondance des sauterelles etait significativement plus faible a l'int erieur des anciens bomas qu' a l'ext erieur, mais la proportion de sauterelles de la sous-famille des Oedipodinae y etait significativement plus elev ee qu' a l'ext erieur. Ceci sugg ere que la v eg etation rar efi ee des bomas abandonn es supporte un nombre plus faible de sauterelles mais qu'une plus grande fraction de l'assemblage de sauterelles dans les bomas abandonn es se compose d'Oedipodinae. Les eleveurs traditionnels ont donc un effet a long terme sur la taille et la composition des assemblages...

Seasonal pattern in population dynamics and host plant use of non‐swarming Ruspolia differens Serville (Orthoptera: Tettigoniidae)

“…Our previous laboratory experiment has also shown that R. differens benefits from mixing different foods in the diet, resulting in a shorter developmental time and higher fresh adult weight and female fecundity (Malinga et al, ). Overall, our results corroborate previous studies that have demonstrated that vegetation structure, quality and quantity are important predictors of Orthopteran population densities (Deveson, ; Lazar, Piou, Doumandji‐Mitiche, & Lecoq, ; Uyehara, Sisanya, Hemp, & Rubenstein, ; Zhu et al, ). Our results, therefore, draw special attention to the availability of diverse grasslands in East Africa, in order to preserve viable natural populations of R. differens in the long term.…”

Defining socially responsible companies according to retail investors’ preferences

“…Moreover, we could not find in the literature research any research relating the above described screening methodologies and retail investors' opinion. Most studies which are interested in retail investors focus on their characteristics and behaviour (Berry & Yeung, 2013;Diouf, Hebb, & Touré, 2016;Michelson, Wailes, Van Der Laan, & Frost, 2004;Pérez-Gladish, Benson, & Faff, 2012;Renneboog, Ter Horst, & Zhang, 2008;Renneboog et al, 2011;Wins & Zwergel, 2014), but they do not analyse how do socially responsible retail investors define the concept of "socially responsible company" or what should be, in their opinion, the goal of sustainable investors (Capelle-Blancard & Monjon, 2012). This is a very important gap that should be filled, because there should be a reasonable compliance between the product which is offered (the socially responsible investment fund) and want the client (the retail investor) expects.…”