Decomposition and nutrient release patterns of mistletoe litters in a semi‐arid savanna, southwest Zimbabwe

Abstract

Nutrient loss from litter plays an essential role in carbon and nutrient cycling in nutrient-constrained environments. However, the decomposition and nutrient dynamics of nutrient-rich mistletoe litter remains unknown in semi-arid savanna where productivity is nutrient limited. We studied the decomposition and nutrient dynamics (nitrogen: N, phosphorous; P, carbon: C) of litter of three mistletoe species, Erianthemum ngamicum, Plicosepalus kalachariensis, and Viscum verrucosum and N-fixing Acacia karroo using the litter-bag method in a semi-arid savanna, southwest Zimbabwe. The temporal dynamics of the soil moisture content, microbial populations, and termite activity during decomposition were also assessed. Decay rates were slower for A. karroo litter (k = 0.63), but faster for the high quality mistletoe litters (mean k-value = 0.79), which supports the premise that mistletoes can substantially influence nutrient availability to other plants. Nitrogen loss was between 1.3 and 3 times greater in E. ngamicum litter than in the other species.The litter of the mistletoes also lost C and P faster than A. karroo litter. However, soil moisture content and bacterial and fungal colony numbers changed in an opposite direction to changes in the decomposition rate. Additionally, there was little evidence of termite activity during the decay of all the species litters.This suggests that other factors such as photodegradation could be important in litter decomposition in semi-arid savanna. In conclusion, the higher rate of decay and nutrient release of mistletoe than A. karroo litter indicate that mistletoes play an important role in carbon and nutrient fluxes in semi-arid savanna.

Enhanced soil nutrient concentrations beneath-canopy of savanna trees infected by mistletoes in a southern African savanna

“…Nutrient enrichment in tree-dominated patches is a widely recognized phenomenon, which increase heterogeneity of resource availability in savannas (Belsky, 1994;Belsky et al, 1989;Ludwig et al, 2004;Mlambo et al, 2005;Treydte et al, 2010). Three major mechanisms have been advanced to explain this phenomenon:…”

“…The nutrient acquisition pathway enables mistletoes to accumulate greater foliar nutrient concentrations than their hosts (Marshall et al, 1994;Ehleringer and Marshall, 1995). At senescence, the litter of mistletoes remains enriched due to a low nutrient resorption efficiency (March and Watson, 2010;Ndagurwa et al, 2013Ndagurwa et al, , 2014a. Such litter decomposes and releases nutrients faster than more recalcitrant litters (Ndagurwa et al, 2014b), and may also stimulate the decomposition of litter of co-occurring species (Quested et al, 2002).…”

“…At senescence, the litter of mistletoes remains enriched due to a low nutrient resorption efficiency (March and Watson, 2010;Ndagurwa et al, 2013Ndagurwa et al, , 2014a. Such litter decomposes and releases nutrients faster than more recalcitrant litters (Ndagurwa et al, 2014b), and may also stimulate the decomposition of litter of co-occurring species (Quested et al, 2002). The enriched litter may also alter soil microbial communities and thus processes in which microbes are involved such as decomposition (Bardgett et al, 2006).…”

“…We are aware of a few studies (e.g., Ndagurwa et al, 2013Ndagurwa et al, , 2014a that have examined the influence of mistletoes on soil nutrient concentrations in semi-arid savanna, which limits our understanding of their ecological function. We studied soil nutrient concentrations beneath mistletoe-infected and uninfected trees (hereafter host and non-host trees, respectively) in semi-arid savanna.…”

Uso de la tierra y ambiente local de descomposición en el Chaco Semiárido de Córdoba, Argentina

“…A CUCHIETTI lado, en las parcelas donde la cobertura vegetal y la cantidad de broza acumulada sobre el suelo es menor, el material a descomponer (broza o en nuestro caso materiales comunes) estaría expuesto a mayor radiación solar y a una mayor degradación como consecuencia de la fotodegradación (Gallo et al 2009;Ndagurwa et al 2015).…”