Nutrient transport within and between habitats through seed dispersal processes by woolly monkeys in north‐western Amazonia

Abstract

The contribution of vertebrate animals to nutrient cycling has proven to be important in various ecosystems. However, the role of large bodied primates in nutrient transport in neotropical forests is not well documented. Here, we assess the role of a population of woolly monkeys (Lagothrix lagothricha lugens) as vectors of nutrient movement through seed dispersal. We estimated total seed biomass transported by the population within and between two habitats (terra firme and flooded forests) at Tinigua Park, Colombia, and quantified potassium (K), phosphorus (P) and nitrogen (N) content in seeds of 20 plant species from both forests. Overall, the population transported an estimated minimum of 11.5 (±1.2 SD) g of potassium, 13.2 (±0.7) g of phosphorus and 34.3 (±0.1) g nitrogen, within 22.4 (±2.0) kg of seeds ha(-1) y(-1). Approximately 84% of all nutrients were deposited in the terra firme forest mostly through recycling processes, and also through translocation from the flooded forest. This type of translocation represents an important and high-quality route of transport since abiotic mechanisms do not usually move nutrients upwards, and since chemical tests show that seeds from flooded forests have comparatively higher nutrient contents. The overall contribution to nutrient movement by the population of woolly monkeys is significant because of the large amount of biomass transported, and the high phosphorus content of seeds. As a result, the phosphorus input generated by these monkeys is of the same order of magnitude as other abiotic mechanisms of nutrient transport such as atmospheric deposition and some weathering processes. Our results suggest that via seed dispersal processes, woolly monkey populations can contribute to nutrient movement in tropical forests, and may act as important nutrient input vectors in terra firme forests.

Global nutrient transport in a world of giants

“…We do not calculate changes to fertility from lateral diffusivity declines because accurate global maps of nutrient hotspots necessary for such a calculation do not exist at the necessary resolution. Previous experimental studies, however, have found that animals move significant quantities of nutrients across concentration gradients despite not necessarily moving dung from fertile to nonfertile areas (11,14,19). Regional models found that the transfer of P away from the Amazonian floodplains may have dropped by more than 50% following the extinction of the Amazonian megafauna (20,21).…”

“…For instance, woolly monkeys (Lagothrix lagotricha) in Amazonia transported more P than arrives from dust inputs across a floodplain concentration gradient, without preferentially defecating in the less fertile area, merely by eating and defecating back and forth across the nutrient concentration gradient (19). If a small single species can transport such significant quantities of P, what is the role of all animals in an ecosystem over long periods of time?…”

Evaluating the effect of nutrient redistribution by animals on the phosphorus cycle of lowland Amazonia

“…In other words, animal movement generates a net transport of P from relatively nutrient-rich to relatively nutrient-poor areas, analogous to a diffusion process, but acting against the gradients of physical flow processes driven by topographic relief. For example, in a study of a woolly monkey (Lagothrix lagotricha lugens) population in northwest- ern Amazon, Stevenson and Guzmán-Caro (2010) showed that this population could import about 1-4 g P ha −1 a −1 from lowland to uplands through seed dispersal. A model based on animal movement as an agent of P redistribution illustrated how megafauna before the Pleistocene extinction could have sustained P cycling in this basin .…”

Bushmeat harvest in tropical forests: Knowledge base, gaps and research priorities

“…In addition, vertebrates can also play a role in nutrient cycling in tropical forests. In the Neotropics, primates increase the availability of accessible forms of nitrogen to plants, increase the speed of nutrient cycling (Feeley and Terborgh 2005), and move nitrogen from the fertile floodplain forests to upland forests that tend to be poor in nutrients (Stevenson and Guzmán-Caro 2010). Although these effects have been documented, the effects of defaunation on nutrient cycling remain poorly understood.…”