Transgressive dunefield landforms and vegetation associations, Doña Juana, Veracruz, Mexico

Abstract

Transgressive dune fi elds often comprise a multiplicity of landforms where vegetation processes largely affect landform dynamics, which in turn, also affect vegetation processes. These associations have seldom been studied in detail. This paper examines four separate landform types in a complex coastal transgressive dunefi eld located in the central Gulf of Mexico, in order to assess the relationships between dunefi eld habitat, local environmental factors, vegetation associations and landform evolution. Topographic surveys using tape and clinometer were conducted in conjunction with vegetation survey transects at four locations across the Doña Juana dunefi eld. Vegetation surveys allowed the estimation of relative plant cover of each plant species found along the transects. A large variety of landforms were found at the Doña Juana Dunefi eld: defl ation plains, gegenwalle (counter) ridges, transverse dune trailing ridges, blowouts and parabolic dunes, aklé (fi sh-scale shaped) dunefi elds and precipitation ridges, with plant species associations developing on these different landforms equally variable. Flood tolerant species were located in the lower parts (defl ation plain and gegenwalle ridges) whereas the older and dryer parts were covered by coastal matorral shrubs. Burial-tolerant species were dominant in the most mobile areas (blowouts and aklé dunefi eld and margin). The dune trailing ridge, with relatively milder conditions, showed the highest richness, with no dominant species. A dual interaction was found such that colonizing species both create and affect topography, and in turn, topography determines vegetation association and succession patterns. In coastal dunes, the vegetation and abiotic environment (namely the different landforms and the inherent micronevironmental variability) interact tightly and generate a complex and highly dynamic biogeomorphic system where substrate mobility and colonization processes reinforce one another in positive feedback.

Relationship between vegetation dynamics and dune mobility in an arid transgressive coastal system, Maspalomas, Canary Islands

“…An important difference between the Maspalomas dune field and dune systems located in temperate and tropical areas, where plants colonize both inter-dune depressions, slopes or crests of mobile dunes (Moreno-Casasola, 1987;Martínez et al, 2001;Tsoar and Blumberg, 2002;Hesp, 2004;Dech and Maun, 2005;Hesp and Martínez, 2008;Hesp et al, 2011), is that the starting point of plant colonization in the transgressive Maspalomas dunes occurs exclusively in both dry and wet inter-dune depressions and deflation surfaces (slacks from the ecological point of view). This seems to be related to the arid characteristics of this system.…”

“…Such studies typically focus on analyzing the relationship between vegetation and its burial by sand. Almost all of these studies have been made at transgressive dune systems in temperate and tropical areas (Moreno-Casasola, 1986;Martínez et al, 1997Martínez et al, , 2001Hesp and Martínez, 2008;Hesp et al, 2011), with only a few analyzing these processes in arid dune systems (Hesp, 2013). The main objective of most of these studies was to analyze the relationship between burial by sand and plants that have directly colonized the dunes.…”

“…Such conditions can lead to fatal burial processes, even for species that are adapted to these conditions, when the sand dunes moving along slacks reach significant heights. Vegetation that survives the burial processes occurring in transgressive systems modifies the morphology of the dunes (Tsoar and Blumberg, 2002;Hesp and Martínez, 2008;Pelletier et al, 2009;Hesp et al, 2011), so it plays an important role in the dynamics and configuration of the systems themselves. Thus, without the presence of plants, numerous landforms would be missing, sandy deposits would continue their advance toward the inner areas, and the space would become a deflation surface (Hesp et al, 2011).…”

“…Vegetation that survives the burial processes occurring in transgressive systems modifies the morphology of the dunes (Tsoar and Blumberg, 2002;Hesp and Martínez, 2008;Pelletier et al, 2009;Hesp et al, 2011), so it plays an important role in the dynamics and configuration of the systems themselves. Thus, without the presence of plants, numerous landforms would be missing, sandy deposits would continue their advance toward the inner areas, and the space would become a deflation surface (Hesp et al, 2011). However, in transgressive dune systems in arid regions with high inputs of sediment, vegetation plays a minor role -an aspect manifested in the scarcity of plant-associated dunes (Hesp, 2013).…”

La investigación científica sobre dunas costeras de México: origen, evolución y retos

“…Posteriormente, Coll-de Hurtado (1969) describió las características geomorfológicas de las dunas parabólicas del sur de Veracruz mediante el uso de imágenes aéreas. En los estudios sobre vegetación se evaluaban, de manera muy superficial, las características del suelo y los tipos de dunas, y no fue hasta 1992 que Dubroeucq, Geissert, Moreno-Casasola y Millot (1992), Hesp et al (2011) y López-Portillo et al (2011 caracterizaron geomorfológicamente y analizaron las características del suelo de las DC de la costa central del golfo de México. En estos trabajos se reconoce un gradiente de distribución de las geoformas que suele coincidir con el gradiente de la vegetación y de la cobertura vegetal, que influyen directamente en las características No.…”