Diversity patterns of monocotiledonous geophytes in Mexico

Abstract

Background: Geophytes, plants with underground perennating organs that lose their aerial organs annually, are able to survive in harsh habitats. This life form is common in the monocots that inhabit Mediterranean climates around the world. In Mexico only the northern area of Baja California has this type of climate. Hypothesis: In this study, we recorded the species and distribution of Mexican geophyte monocots to pinpoint diversity hotspots. Our hypothesis is that the highest diversity of geophytes will be found in biogeographic areas with complex topography and seasonal climate not only in the north of the Baja California Peninsula. Data description: Records of geophytes were taken from different sources, collections, taxonomic references and diversity databases. Geophyte locations were mapped in the context of biogeographic and protected areas. Climate preferences were estimated using bioclimatic variables and by a Principal Component Analysis we identified the most significant variables explaining distribution of geophytes. Results: The Mexican geophyte flora is composed of 476 species, approximately 10 % of the total diversity of monocots. Echeandia and Tigridia were the two most diverse genera. This flora is dominated by the taxa of Orchidaceae, Asparagaceae and Iridaceae, and ten small endemic genera were recorded. Geophyte diversity was highest in two biogeographic provinces: the Trans-Mexican Volcanic Belt and the Sierra Madre del Sur, in dry forests such as oak-pine, seasonally dry tropical forests and semi-arid shrubby vegetation. Three bioclimatic variables: temperature seasonality, annual precipitation and precipitation of the wettest quarter resulted significant for understanding distribution of geophytes. Conclusions: Areas sustaining a high diversity and endemism of geophytes are located in the Mesoamerican Biodiversity Hotspot, in unprotected and threatened areas. Our results suggest that geophytes are able to grow in different climates but in areas with marked temperature seasonality and variation of annual precipitation. Keywords: Balsas River Basin, Chiapas Depression, Echeandia, endemism, Tigridia, Tehuacán Valley, Trans-Mexican Volcanic Belt Patrones de diversidad de geofitas monocotiledóneas en México ResumenAntecedentes: Las geofitas son plantas que poseen órganos de perennación subterráneos, las cuales pierden sus hojas anualmente y son capaces de sobrevivir en ecosistemas inhóspitos. Esta forma de vida es común en las monocotiledóneas que habitan en áreas con clima Mediterráneo en todo el mundo. En México únicamente el área norte de Baja California tiene este tipo de clima. Hipótesis: En este estudio se registra la diversidad y endemismo de las geofitas monocotiledóneas en México para identificar áreas con alta diversidad. Nuestra hipótesis plantea que la más alta diversidad de geofitas monocotiledóneas se encontrará en provincias biogeográficas con topografía compleja y variados tipos de climas y no solamente en Baja California. Descripción de Datos: Se elaboró una lista de geo...

Richness, geographic distribution patterns, and areas of endemism of selected angiosperm groups in Mexico

“…This pattern is similar to the results obtained by others (Cruz‐Cárdenas et al, ; Vargas‐Amado et al, ; Munguía‐Lino et al, ; Villaseñor, ). The richness analyzes on the Mexican (Cuéllar‐Martínez & Sosa, ) and Mesoamerican monocotyledonous geophytes (Sosa & Lorea, ) uncovered the same pattern.…”

The monocotyledonous underground: global climatic and phylogenetic patterns of geophyte diversity

“…For example, bulbous taxa (i.e., those with true bulbs) have been noted to occupy more open, xeric habitats in Liliaceae and Iridaceae, whereas the rhizomatous taxa appear to have maintained an ancestral‐like growth form (i.e., rhizome) and environment (i.e., forested) (Patterson and Givnish, ; Wilson, ). Recently, studies have examined these patterns from a statistical and/or phylogenetic viewpoint (Evans et al., ; Cuéllar‐Martínez and Sosa, ; Sosa et al., ; Sosa and Loera, ), and support the hypothesis of a relationship existing between particular climatic niches and different geophytes. However, many of these investigations lumped geophyte diversity into a single category and did not examine the evolution of individual USO growth forms, and/or they did not compare the relationship between geophytes and non‐geophytes (e.g., trees, epiphytes, etc.…”

“…Geophytic taxa are found throughout the plant tree of life and have a widespread geographic distribution, but are particularly diverse in Mediterranean ecosystems (Rundel, ; Hoffmann et al., ; Parsons and Hopper, ; Procheş et al., ). Although our overall knowledge of geophytes is slowly improving—in particular, the evolution of different underground traits (Patterson and Givnish, ; Wilson, ; Sosa et al., ; Stoughton et al., ) and the ecological factors controlling their distribution (Evans et al., ; Cuéllar‐Martínez and Sosa, ; Sosa and Loera, )—the economic and evolutionary importance of these taxa warrant increased scientific attention. To date, most studies pertaining to geophyte evolution have focused on a handful of taxonomic groups (Patterson and Givnish, ; Perret et al., ; Wilson, ; Oberlander et al., ; Evans et al., ; Sosa et al., ) or geographic regions (Pate and Dixon, ; Rundel, ; Hoffmann et al., ; Parsons, ; Parsons and Hopper, ; Cuéllar‐Martínez and Sosa, ; Sosa and Loera, ).…”

“…It has been shown that temperature seasonality, annual precipitation, and precipitation of the wettest quarter explain the current distribution of monocotyledonous geophytes within Mexico (Cuéllar‐Martínez and Sosa, ). In a subsequent phylogenetically‐based study of the same flora, Sosa et al.…”

Tunicate bulb size variation in monocots explained by temperature and phenology

“…Underground storage organ (USO) size influences several life-history processes as well, such as leaf emergence, flowering, and seed set (Dafni, Cohen, et al, 1981;Dafni, Shmida, et al, 1981;Han, 2001;Hertogh, 1996;Rees, 1966Rees, , 1969Rees, , 1972. Belowground reserves can be drawn upon to divide apical cells during the dormant season in order to rapidly fill these cells at the onset of the growing season (Grime & Mowforth, 1982), which can allow for relatively earlier emergence, and maximum capture of available resources (e.g., light, water) that are typically in short supply, given the highly seasonal climates that many geophytic taxa inhabit (Cuéllar-Martínez & Sosa, 2016;Howard, Folk, Beaulieu, & Cellinese, 2019;Rees, 1989). USO size can also be used as a proxy for flowering (i.e., once a bulb is a certain diameter it should flower) (De Mastro & Ruta, 1993;Han, 2001;Hanzawa & Kalisz, 1993), although adequate USO size must be obtained before flowering can occur (Dafni, Cohen, et al, 1981;Dafni, Shmida, et al, 1981;Hanzawa & Kalisz, 1993).…”