Insights into past land-use and vegetation change in the Llanos de Moxos (Bolivia) using fungal non-pollen palynomorphs

Nicholas J.D Loughlin,Francis E Mayle,Noelia B Nuñez Otaño,Jennifer M.K O'Keefe,Neil A Duncan,John H Walker,Bronwen S Whitney

doi:10.1016/j.jas.2021.105382

Abstract

Here we document a 1000-year fungal record from the raised-field region of the Llanos de Moxos, a seasonally inundated forest-savanna mosaic in the Bolivian Amazon. Fungi are extremely sensitive to changes in vegetation due to their close relationship with the local environment, providing a useful proxy for past local vegetation and land-use change. Here the remains of fungal non-pollen palynomorphs (NPPs) are identified from a sediment core taken from Laguna El Cerrito. A multivariate constrained ordination is used to extract relationships between the fungal NPP types and environmental gradients, specifically, tree cover, near-shore vegetation, crop cultivation, burning and local sediment input. NPP types such as Neurospora cf. cerealis are identified as indicative of pre-European agriculture and offer the ability to expand on the temporal range of cultivation in the raised-field region. Constrained cluster analysis indicates that the most significant changes in the NPP assemblage occurs c. 1500 and c. 1700 CE, corresponding to the arrival of Europeans to the Americas and Jesuit missionaries to the Llanos de Moxos respectively. The modern savanna landscape is one shaped by changes in land-use and the introduction of cattle following the European Encounter.

Highlights

Indigenous peoples have inhabited the Llanos de Moxos region of Bolivia for at least the last 10,000 years, cultivating crops and using fire to manage the landscape (Brugger et al, 2016; Capriles et al, 2019; Lombardo et al, 2020)
This study aims to (1) identify the key fungal taxa from the seasonally-inundated savanna of northern Bolivia, (2) incorporate these fungal non-pollen palynomorphs (NPPs) into a multiproxy recon struction of land-use change in the Moxos, and (3) identify specific fungal taxa that can be used to aid in reconstructing periods of preColumbian raised field agriculture
Seventy-eight distinct morphological fungal NPP types were identi fied from the LEC core, of which fifty-two met the requirements of the presence (≥2% abundance in one sample) and persistence filters (Plate 1)

Summary

Introduction

Indigenous peoples have inhabited the Llanos de Moxos (or ‘Moxos’) region of Bolivia for at least the last 10,000 years, cultivating crops and using fire to manage the landscape (Brugger et al, 2016; Capriles et al, 2019; Lombardo et al, 2020). NPPs have been successfully used to examine changes in pastoral and grazing activity (Cugny et al, 2010; Gauthier et al, 2010; Gill et al, 2013; van Asperen et al, 2020), herbivore extinctions (Davis, 1987; Gill et al, 2009), fire frequency (Stivrins et al, 2019), Neolithic woodland management (Innes et al, 2010), human landscape modification (Willemsen et al, 1996) and aid in reconstructing Norse (Schofield and Edwards, 2011) and Roman settlements (van Geel et al, 2003) While their use was initially developed in northern temperate peat bogs (van Geel, 1972, 1976, 1978) their incorporation into the reconstruction of past ecosystems in tropical South America has increased substantially in the last decade (Leal et al, 2019; Loughlin et al, 2018; Medeanic and Silva, 2010; Montoya et al, 2010, 2011, 2012; Musotto et al, 2017; Nunez Otano et al, 2017; Stutz et al, 2010). The application of fungal remains, to palaeoecological and archaeological questions has continued to expand as their utility in interpreting the past is realised (der Linden et al, 2012; Haas, 2010; van Geel, 2001)

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