See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/222149229 Poaceae phytoliths from the Niassa Rift, Mozambique Article in Journal of Archaeological Science · August 2010 DOI: 10.1016/j.jas.2010.03.001 CITATIONS READS 44 409 9 authors, including: Fernando Astudillo Mary Barkworth Universidad San Francisco de Quito (USFQ) Utah State University 4 PUBLICATIONS 45 CITATIONS 81 PUBLICATIONS 902 CITATIONS SEE PROFILE SEE PROFILE Tim Aaron Bennett Chris Esselmont 8 PUBLICATIONS 242 CITATIONS The University of Calgary 6 PUBLICATIONS 161 CITATIONS SEE PROFILE SEE PROFILE Some of the authors of this publication are also working on these related projects: Stipeae (no longer a major focus) View project Grasses in North America View project All content following this page was uploaded by Rahab N Kinyanjui on 19 March 2018. The user has requested enhancement of the downloaded file. Journal of Archaeological Science 37 (2010) 1953e1967 Contents lists available at ScienceDirect Journal of Archaeological Science journal homepage: http://www.elsevier.com/locate/jas Poaceae phytoliths from the Niassa Rift, Mozambique Julio Mercader a,*, Fernando Astudillo a, Mary Barkworth b, Tim Bennett a, Chris Esselmont c, Rahab Kinyanjui d, Dyan Laskin Grossman a, Steven Simpson a, Dale Walde a a Department of Archaeology, University of Calgary, 2500 University Drive N.W., Calgary, Alberta T2N 1N4, Canada b Intermountain Herbarium, Utah State University, 5305 Old Main Hill, Logan, UH 84322-5305, USA c Environics Research Group, 999 8th Street S.W., Calgary, Alberta T2R 1J5, Canada d National Museum of Kenya, Department of Earth Sciences, Palynology and Paleobotany Section, P.O. Box 40658-00100, Nairobi, Kenya article info abstract Article history: The most common grass phytoliths from “Zambezian” miombos are described here for the first time. Received 18 January 2010 Their potential for long term preservation in sediments makes them a useful tool in the reconstruction of Received in revised form ancient plant communities and plant/human interactions. We processed 60 plant samples (26 identified 26 February 2010 genera and species), with an average of 300 phytoliths counted per sample to a total of 18,586. Forty- Accepted 1 March 2010 seven morphotypes were described as per the International Code for Phytolith Nomenclature, with exceptions, including forty-five discreet shapes and two articulated forms, which can be used as Keywords: comparative reference materials. We conducted three forms of statistical analyses: Discriminant Anal- Poaceae Phytoliths Great African Rift ysis, Cluster Analysis, and Principal Component Analysis. The highest biomineral content was recorded Mozambique, Niassa among the Bambuseae and Paniceae, while the lowest silica production is detected in the Cynodonteae Miombo Woodlands tribe. Typologically, the subfamily Panicoideae yielded 50% of the types reported here, 32% are from the Paleoenvironment Chloridoideae, 12% from the Bambusoideae, and 8% from the Arundinoideae sensu lato. Overall, the Discriminant Analysis, Principal Component idealized Zambezian Poaceae phytolith spectrum is dominated by a small subset of Poaceae short cells, Analysis, and Cluster Analysis which include five morphotypes conventionally associated with Panicoid grasses (Bilobate concave outer margin long shaft, Bilobate concave outer margin short shaft, Bilobate convex outer margin long shaft, Bilobate convex outer margin short shaft, Cross), one morphotype commonly seen in Chloridoid taxa (saddle), and two types that appear across subfamily boundaries (tower, tower horned). The next logical step to take in regional phytolith research is the account of phytoliths deposited in soils underneath living plants, for they represent the interface between existing vegetation communities and the inevi- tably distorted fossil assemblages that the paleobotanist uses for environmental reconstruction. Ó 2010 Elsevier Ltd. All rights reserved. 1. Introduction scarcity is in contrast with the long-standing investigations of silica bodies among the European grasses; dating as far back as African archaeologists are interested in phytoliths from the late 19th and 20th centuries (see review of early work in Parry modern, reference plants to reconstruct the landscape that served and Smithson, 1964). In other parts of the world, the phytoliths as environmental background to human evolution. Recent studies extracted from living Poaceae have been subjected to qualitative of African extracellular and intracellular silicifications from grasses and quantitative analysis; for example, in South East Asia (Whang have advanced our understanding of phytoliths from live plants in et al., 1998; Lu and Liu, 2003a), India (Krishnan et al., 2000), three phytochoria (White, 1983): the Somalia-Masai (Palmer and Western Melanesia (Boyd et al., 1998), the New Zealand grasslands Tucker, 1981, 1983; Palmer et al., 1985; Palmer and Gerbeth- (Marx et al., 2004; Thorn, 2004, 2008), the European Atlantic Jones, 1986; Ball et al., 2002; Barboni and Bremond, 2009), zone, as well as the Alpine and Mediterranean regions (Parry and Sudano-Sahelian (Fahmy, 2008), and Guineo-Congolian (Runge, Smithson, 1964; Ollendorf et al., 1988; Kaplan et al., 1992; Carnelli 1999) vegetation zones. Quantitative information on the amount et al., 2004; Tsartsidou et al., 2007). Grass reference collections and types of biogenic silica produced by African grassy plants, have also been developed in North America (Blackman, 1971; however, is very limited (cf. Albert and Weiner, 2001). This Brown, 1984; Fredlund and Tieszen, 1994; Blinnikov, 2005), the Neotropics (Piperno and Pearsall, 1998) and South America (Zucol, * Corresponding author. 1998; Iriarte, 2003; Gallego and Distel, 2004; Fernández Honaine E-mail address: [email protected] (J. Mercader). et al., 2006). 0305-4403/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.jas.2010.03.001 1954 J. Mercader et al. / Journal of Archaeological Science 37 (2010) 1953e1967 Biogenic silica may be preserved for long periods of time. 2. Methodology Phytolith analysis is a valuable tool for reconstructing ancient plant communities' physiognomy and structure (Retallack, 1992; The botanical specimens studied in this paper include those Alexandre et al., 1997; Barboni et al., 1999; Mercader et al., collected by our crew from two localities; Metangula (Lago district, 2000; Albert et al., 2006; Barboni et al., 2007; Strömberg et al., lowlands) and Njawala (Sanga district, highlands) in Niassa, 2007), especially in the field of paleoagrostology (for the most Northern Mozambique. Our reference collection is deposited at the recent treatment of Poaceae phylogenetics see G.P.W.G., 2001; Tropical Archaeology Laboratory at the University of Calgary, Bouchenak-Khelladi et al., 2008). The analysis of phytoliths from Canada. The collection procedure was governed by 5 km-radius living plant tissues helps establish rates of silica production in transects where all grasses encountered were collected, as well as ecosystems of known floristic composition, determines the all the trees and shrubs (Mercader et al., 2009). Mature specimens frequency of different morphotypes in a given regional phytolith were taken during the dry season to ensure better phytolith build spectrum, and highlights the types that, because of prominence, up in their tissues. Specimens from other regions and neighboring indicate likely membership to a subfamily, tribe or genus. In this countries believed to be significant for our study were included in context, we aim to fill the existing gap in phytolith research of the this paper as well. Some samples were obtained from the Pretoria most common Poaceae species in the African woodlands growing Herbarium, SANBI (South Africa), while others were donated along the Niassa Rift of Mozambique. From a quantitative generously by Dr. E. Arnold (University of Illinois, Urbana-Cham- perspective, we verify whether specific morphotypes are solid pagne, USA). The primary source for grass identification was the indicators of taxonomic affiliation and environmental predictors, manual by Gibbs Russell (1988) and Gibbs Russell et al. (1991). establish the relative composition of the overall phytolithic spec- In some instances we also consulted Barkworth et al. (2007). Tribal trum that a “Zambezian” grassy cover would leave behind in the nomenclature is from Clayton and Renvoize (1986). We follow the geological and archaeological record, and discuss whether the index of accepted names for the flowering plants of Sub-Suharan lessons learned from modern local phytoliths can be of any Africa (Klopper et al., 2006). guidance for future research in prehistoric plant landscape Our botanical collection represents 75% of the most common composition and climatic trends in the woodlands, savannas, and grass genera from Niassa (Gama, 1990; da Silva et al., 2004; grasslands surrounding the Great African Rift. Timberlake et al., 2004; Bloesch and Mbago, 2006; Ribeiro et al., In addition to being the largest phytochorion in sub-Saharan 2008)(Table 1), and provides data on an additional 16, less prom- Africa, the “Zambezian” zone contains the richest and most inent local genera. In total, we study the phytoliths from 60 diverse flora and vegetation in Africa (White, 1983,pp.89).The botanical specimens (Appendix A, supplementary material online) Flora Zambesiaca contains an estimated 11,400 taxa, half of representing 26 genera and 26 confirmed