Strategies of diaspore dispersal investment in Compositae: the case of the Andean highlands

• DOI: 10.1093/aob/mcad099
• Publication Date: 2023-07-28T07:37:59Z
• Authors: Carolina Tovar; Lucia Hudson; Francisco Cuesta; Rosa Isela Meneses; Priscilla Muriel; Oriane Hidalgo; Luis Palazzesi; Carlos Suarez Bal...; Eleanor Hammond Hunt; Mauricio Diazgran...; D J Nicholas Hind; Félix Forest; Stephan Halloy; Nikolay Aguirre; William J Baker; Stephan Beck; Julieta Carilla; Paúl Eguiguren; Elaine Françoso; Luis E Gámez; Ricardo Jaramillo; Luis Daniel Llambí; Olivier Maurin; Inga Melcher; Gemma Muller; Shyamali Roy; Paul Viñas; Karina Yager; Juan Viruel
• Keywords: 570; Alpine ecosystems; Compositae; Diaspore (botany); Abiotic component; Diaspore morphological traits; Seed dispersal; Climate; Population; Plant Science; Asteraceae; Agricultural and Biological Sciences; Biodiversity Conservation and Ecosystem Management; Sociology; Biological dispersal; Achene; Biology; Phylogeny; Ecosystem; Ecology, Evolution, Behavior and Systematics; Nature and Landscape Conservation; Demography; 580; Diaspore investment; Tropical Andes; Ecology; Botany; Life Sciences; Original Articles; Diversity and Applications of Cyperus Species; 15. Life on land; FOS: Sociology; FOS: Biological sciences; Environmental Science; Physical Sciences; Impact of Pollinator Decline on Ecosystems and Agriculture; Habitat Fragmentation

Abstract

Background and Aims Understanding diaspore morphology and how much a species invests on dispersal appendages is key for improving our knowledge of dispersal in fragmented habitats. We investigate diaspore morphological traits in high-Andean Compositae and their main abiotic and biotic drivers and test whether they play a role in species distribution patterns across the naturally fragmented high-Andean grasslands.

Methods We collected diaspore trait data for 125 Compositae species across 47 tropical high-Andean summits, focusing on achene length and pappus-to-achene length ratio, with the latter as a proxy of dispersal investment. We analysed the role of abiotic (temperature, elevation and latitude) and biotic factors (phylogenetic signal and differences between tribes) on diaspore traits and whether they are related to distribution patterns across the Andes, using phylogenomics, distribution modelling and community ecology analyses.

Key Results Seventy-five percent of the studied species show small achenes (length <3.3 mm) and 67% have high dispersal investment (pappus length at least two times the achene length). Dispersal investment increases with elevation, possibly to compensate for lower air density, and achene length increases towards the equator, where non-seasonal climate prevails. Diaspore traits show significant phylogenetic signal, and higher dispersal investment is observed in Gnaphalieae, Astereae and Senecioneae, which together represent 72% of our species. High-Andean-restricted species found across the tropical Andes have, on average, the pappus four times longer than the achene, a significantly higher dispersal investment than species present only in the northern Andes or only in the central Andes.

Conclusions Small achenes and high diaspore dispersal investment dominate among high-Andean Compositae, traits typical of mostly three tribes of African origin; but traits are also correlated with the environmental gradients within the high-Andean grasslands. Our results also suggest that diaspore dispersal investment is likely to shape species distribution patterns in naturally fragmented habitats.