Life History Strategies of woody species in relation to proximity of termite mounds in an African savanna

Termite mounds are nutrient ‘hotspots’ that influence the structure and composition of the vegetation on the mounds. Due to high nutrient concentration in the termitarea vegetation, these plants are highly palatable and thus are more heavily utilized by herbivores. High herbivory on the mounds reduces plant biomass, meaning these plants are less susceptible to fire. This study proposes that trees on and off termite mounds exhibit different life history strategies (LHS) based on these factors. LHS can be inferred from measuring certain characteristics, such as plant functional traits (PFTs): plant height, number of stems, bark thickness, spinescense, and branch ramification. There are no significant differences in functional traits on and off mounds except for the number of stems and average number of spines, but this seems to be species dependent. Dichrostachys cinerea had on average more stems on the mound than off the mound (6.4+/- 1.049 and 3.297+/- 0.440 respectively) and Acacia exuvialis had more spines (12.982 +/-.423). These findings suggest that the life history strategies of specific species dictate the PFT’s of a plant, rather than its location on or off the mound.白蚁丘（termite mounds）是养分"热点"，可影响丘体周边植被的结构与组成。由于白蚁丘区域内的植被养分浓度较高，此类植物适口性极佳，因此更容易被草食动物取食利用。丘体上的高强度草食作用会降低植物生物量，进而使得这些植物更不易受火灾影响。本研究提出，基于上述因素，白蚁丘上与丘外的树木会呈现出不同的生活史策略（life history strategies, LHS）。生活史策略可通过测定特定特征加以推断，例如植物功能性状（plant functional traits, PFTs）：植物高度、茎秆数量、树皮厚度、棘刺特征以及枝条分枝方式。除茎秆数量与平均棘刺数外，丘体上下的植物功能性状并无显著差异，但这一现象似乎因物种而异。二蕊合欢（Dichrostachys cinerea）在丘体上的平均茎秆数量多于丘外（分别为6.4±1.049与3.297±0.440），而脱壳金合欢（Acacia exuvialis）的平均棘刺数量更多（12.982±0.423）。这些研究结果表明，植物的功能性状由特定物种的生活史策略所决定，而非其生长位置是否处于白蚁丘上。