Woody population distribution and environmental heterogeneity in a Chaco forest, Argentina

Barberis, Ignacio M.; Batista, William B.; Pire, Eduardo Félix; Lewis, Juan Pablo; León, Rolando J.C.

doi:10.1658/1100-9233(2002)013[0607:wpdaeh]2.0.co;2

Cited by 11 publications

(19 citation statements)

References 23 publications

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“…The fruit traits of M. coquimbensis are strongly indicative of vertebrate dispersal; this is consistent with other Myrcyanthes species in the Neotropics, which are dispersed by birds and/ or monkeys (Barberis et al 2002, Pizo 2002, Wilms and Kappelle 2006. However, as mentioned previously there are no present-day dispersers of M. coquimbensis.…”

Section: Discussionsupporting

confidence: 87%

Seed predation by rodents results in directed dispersal of viable seed fragments of an endangered desert shrub

et al. 2014

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Abstract. Seed predation and seed dispersal are important ecological processes with antagonistic effects on plant recruitment. In the southern edge of the Atacama Desert in Chile, Myrcianthes coquimbensis is an endangered, large-seeded, vertebrate-dispersed shrub that in the present-day has no known dispersers. Native rodents hoard and eat the seeds of M. coquimbensis but leave viable seed fragments at the hoarding sites; soil interspaces within rock outcrops where seedlings recruit. Here we examined whether rodents act as effective dispersers of M. coquimbensis by discarding viable seed fragments in sites suitable for recruitment. We simulated different levels of endosperm loss to determine if seedlings could develop from seed fragments. We assessed how frequently rodents discarded fragments, and the probability that these fragments produced seedlings. Finally, we compared emergence and seedling survival at the hoarding sites and in two other habitats where seeds arrive to evaluate the suitability of the hoarding sites. Seeds of M. coquimbensis developed seedlings even after 87% of their storage tissue was removed. Rodents left seed fragments in more than 50% of the trials; almost 60% of the discarded fragments produced seedlings. Seedlings did not emerge from open ground habitats, and emergence was higher under M. coquimbensis shrubs than in rock habitats. Survival of two-year-old seedlings was higher in rock habitats than under conspecific adult shrubs. Our results suggest that rodents may play a dual role in the recruitment dynamics of M. coquimbensis, acting simultaneously as seed predators and effective dispersers. Therefore, though seed predators impose costs, their net effect on plant fitness in this system-where dispersers of largeseeded species have been lost-is likely positive.

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Section: Discussionsupporting

confidence: 87%

Seed predation by rodents results in directed dispersal of viable seed fragments of an endangered desert shrub

et al. 2014

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“…The structure and floristic composition change markedly in tens of meters in relation to microtopography and soil moisture. Tree and shrub densities are higher in areas with convex topography (Barberis et al 2002), where there are also dense populations of the two studied bromeliads: B. serra and A. distichantha (Barberis and Lewis 2005).…”

Section: Methodsmentioning

confidence: 89%

“…For instance, the higher frequency and abundance of Schinopsis balansae seeds on both bromeliad species than on the soil could be related to its anemochorous dispersal syndrome (samaras) (Barberis et al 2002). Samaras generally have high terminal velocities, thus collisions with small vegetation elements (e.g.…”

Section: Discussionmentioning

confidence: 99%

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Terrestrial bromeliads as seed accumulation microsites in a xerophytic forest of Southern Chaco, Argentina

2011

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Terrestrial bromeliads as seed accumulation microsites in a xerophytic forest of SouthernChaco, Argentina SUMMARYThe understory of the Schinopsis balansae forests of Southern Chaco is frequently covered by dense populations of two bromeliad species (Aechmea distichantha and Bromelia serra). These bromeliads usually act as traps capturing propagules and litter falling from the canopy. Some populations of these bromeliad species have been removed to ease cattle management, without considering their possible effects on forest regeneration. Therefore, the objective of this work was to evaluate the importance of both bromeliads as microsites for seed accumulation of woody and herbaceous species. Ten plots with bromeliads were selected, where one soil sample and one plant of each species were taken. From the material collected among bromeliad leaves, the seeds and propagules were separated. Likewise, soil samples were washed and the seeds were separated from the litter collected. Seeds were determined to morphospecies and counted. There were 352 seeds (230 on bromeliads and 122 in the soil) from 48 species (10 woody and 38 herbaceous species). Seed abundance of woody species was higher on bromeliad plants (70 seeds) than on the soil (six seeds). In contrast, a higher richness of herbaceous species was recorded on the soil. Therefore, both bromeliads seem to be important microsites for seed accumulation of woody species. However, it is not known whether bromeliads are a safe site for seedling establishment.Key words: bromeliads, Chaco, seeds, understory. RESUMENEl sotobosque de los quebrachales de Schinopsis balansae del Chaco Oriental está frecuentemente cubierto por densas poblaciones de dos bromeliáceas terrestres (Aechmea distichantha y Bromelia serra). Estas bromeliáceas actúan como trampas que capturan propágulos y hojarasca que cae desde la copa de los árboles. Estas poblaciones son a veces removidas para facilitar el manejo del ganado, sin considerar los posibles efectos sobre la regeneración del bosque. El objetivo de este trabajo fue evaluar la importancia de ambas bromeliáceas como micrositios para la acumulación de semillas de especies leñosas y herbáceas. En diez áreas con bromeliáceas, se tomó una muestra de suelo y una planta de cada especie. Se procesó el material colectado entre las hojas de las bromeliáceas, separando las semillas. Además, se lavaron las muestras de suelo, separando las semillas de la hojarasca colectada. Las semillas fueron determinadas al nivel de morfoespecie y contadas. Se registraron 352 semillas (230 sobre bromeliáceas y 122 en el suelo) de 48 especies (10 leñosas y 38 herbáceas). Las semillas de leñosas fueron más abundantes en las plantas de bromeliáceas (70 semillas) que en el suelo (seis semillas). Por el contrario, se registró una mayor riqueza de especies herbáceas en el suelo. Por consiguiente, ambas bromeliáceas parecen ser importantes micrositios para la acumulación de semillas de leñosas. Sin embargo, no se sabe si las bromeliáceas constituyen un micrositio propicio p...

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“…Despite the expected predominant role of light and stress tolerance in filtering understory vegetation, bromeliads were able to occupy the shadier parts of the forest (with high PAI) and, due to their aggregated spatial organization, other life forms were excluded from these sites. Bromeliads have been shown before to affect the presence and density of other plant groups within forests (Brokaw 1983;Wada 1993;Barberis et al 2002;Barberis & Lewis 2005). Nevertheless, in these studies, bromeliads had different effects on understory vegetation by either promoting regeneration or inhibiting other plant groups.…”

Section: Discussionmentioning

confidence: 88%

The role of terrestrial bromeliads in determining the spatial organization of plant life forms in a tropical coastal forest

et al. 2017

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Th e interplay betw een plant-plant interactions and light heterogeneity in the understory of tropical forests has rarely been examined. We aimed to identify the relative importance of the understory light environment and terrestrial bromeliads in explaining the abundance and spatial organization of diff erent plant life forms along a coastal forest gradient from seashore inland in southeastern Brazil. We estimated the abundance of various life forms (herbs, woody plants, bromeliads, climbers, and palms) and the degree of light availability using hemispherical photographs in 165 plots (1 m 2 ) within a 1.75 ha site. We used ordination methods, partial redundancy analysis (pRDA), spatial fi ltering using Moran's eigenvector mapping, and Moran's I splines. Forest cover was highly heterogeneous, but did not explain variation in abundance of life forms. Spatially, bromeliads were negatively associated with woody saplings, herbs and climbing plants at scales between 5-20 m, while the distance to seashore was found to be unrelated to these patterns. Our fi ndings revealed that terrestrial bromeliads play an important role in the spatial organization of various life forms near the forest fl oor. Overall, the presence of terrestrial bromeliads and the plant area index better explained the understory vegetation than forest cover and distance to seashore.

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Woody population distribution and environmental heterogeneity in a Chaco forest, Argentina

Cited by 11 publications

References 23 publications

Seed predation by rodents results in directed dispersal of viable seed fragments of an endangered desert shrub

Seed predation by rodents results in directed dispersal of viable seed fragments of an endangered desert shrub

Terrestrial bromeliads as seed accumulation microsites in a xerophytic forest of Southern Chaco, Argentina

The role of terrestrial bromeliads in determining the spatial organization of plant life forms in a tropical coastal forest

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