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This dataset comprises plant wax n-alkane chain length concentrations and C25-C35 relative abundances of 209 plant specimens from two Kenyan C3-dominated ecosystems, representing a wide range of plant functional types (PFTs). Plant samples were collected in 2018 from Mount Kenya National Park (n=122) and Kakamega National Forest (n=87). At Mount Kenya National Park, samples were collected along an elevational transect (~2400 m to ~3600 m above sea level) from five different ecotones: lower montane forest, bamboo zone, upper montane forest, ericaceous shrubland belt and Afroalpine moorland. Kakamega National Forest is ~1600m above sea level and samples were collected from an open glade, forest path edge, and closed canopy forest. All plant samples were identified to family level, most to genus or species level. Information on collection habitat, photosynthetic pathway, and plant functional type are included. The goal of this dataset was to assess n-alkane distributions for chemotaxonomic signals. Sample analysis took place at Lamont-Doherty Earth Observatory and Harvard University between 2022-2024. n-Alkane data were quantified using a gas chromatograph mass selective detector (GC-MSD) and a flame ionization detector (FID), and response factor corrections were calculated and applied to measured n-alkane peak areas in order to calculate corrected concentrations. The odd n-alkane C25-C35 concentrations were relativized to sum to 1 for the final relative abundance data. For more detailed information, please consult the associated manuscript on the n-alkane distributions and their chemotaxonomic significance: Tweedy et al., 2025. 

Abstract PremiseSeed dispersal is a critical process impacting individual plants and their communities. Plants have evolved numerous strategies and structures to disperse their seeds, but the evolutionary drivers of this diversity remain poorly understood in most lineages. We tested the hypothesis that the evolution of wind dispersal traits within the melicgrasses (Poaceae: Meliceae Link ex Endl.) was correlated with occupation of open and disturbed habitats. MethodsTo evaluate wind dispersal potential, we collected seed dispersal structures (diaspores) from 24 melicgrass species and measured falling velocity and estimated dispersal distances. Species’ affinity for open and disturbed habitats were recorded using georeferenced occurrence records and land cover maps. To test whether habitat preference and dispersal traits were correlated, we used phylogenetically informed multilevel models. ResultsMelicgrasses display several distinct morphologies associated with wind dispersal, suggesting likely convergence. Open habitat taxa had slower‐falling diaspores, consistent with increased wind dispersal potential. However, their shorter stature meant that dispersal distances, at a given wind speed, were not higher than those of their forest‐occupying relatives. Species with affinities for disturbed sites had slower‐falling diaspores and greater wind dispersal distances, largely explained by lighter diaspores. ConclusionsOur results are consistent with the hypothesized evolutionary relationship between habitat preference and dispersal strategy. However, phylogenetic inertia and other plant functions (e.g., water conservation) likely shaped dispersal trait evolution in melicgrasses. It remains unclear if dispersal trait changes were precipitated by or predated changing habitat preferences. Nevertheless, our study provides promising results and a framework for disentangling dispersal strategy evolution. 

The assembly of Africa’s iconic C₄grassland ecosystems is central to evolutionary interpretations of many mammal lineages, including hominins. C₄grasses are thought to have become ecologically dominant in Africa only after 10 million years ago (Ma). However, paleobotanical records older than 10 Ma are sparse, limiting assessment of the timing and nature of C₄biomass expansion. This study uses a multiproxy design to document vegetation structure from nine Early Miocene mammal site complexes across eastern Africa. Results demonstrate that between ~21 and 16 Ma, C₄grasses were locally abundant, contributing to heterogeneous habitats ranging from forests to wooded grasslands. These data push back the oldest evidence of C₄grass–dominated habitats in Africa—and globally—by more than 10 million years, calling for revised paleoecological interpretations of mammalian evolution.