Diversidad y Productividad del Estrato Herbáceo en una Sabana de la Sierra Fría, Aguascalientes

Abstract

To determine species richness, abundance, and alpha diversity indexes to estimate primary productivity and to obtain rain-use efficiency factor in the savannah ecosystem at the Natural Protected Area Sierra Fria, Aguascalientes, we collected 28 phyto-ecological samples randomly. The floristic composition was determined in an area of 256 m 2 and species abundance in a four-meter line, observing 100 points space out each four cm. We estimate diversity by the Shannon-Wienner index (H´). Four exclusions of 144 m 2 each one were established to measure aerial biomass in the rainy season. Samples were measured with a rectangle of 1000 cm 2 area with four replicates per exclusion. Our results showed 219 species of which 20% were graminae and 6.8% leguminosae.Of the total, 14% were dominant, of which, 17 species were graminae and 13 have some forage value. With respect to alpha diversity index, the lowest value was H'= 3.09 and the highest was H'= 3.87. Mean production of biomass was of 2,330 kg of aerial dry matter per hectare in a year, and an annual mean precipitation of 537 mm. Rain use efficiency (RUE) factor, which is the quotient of annual primary production by annual rainfall, was 4.3 kg ha -1 mm -1. Comparing our results with other regions, richness, diversity was high and the rain-use efficiency factor obtained corresponded to the correct range managed. Species with high forage value were not many and most dominant species had poor forage value.Key words: Rangeland. Primary productivity. Floristic composition. Rain-use efficiency factor. IntroducciónLas sabanas son ecosistemas que proporcionan bienes y servicios como leña, postes y forraje, además son zonas de recreación y cacería cinegética, regulan el ciclo hidrológico y mantienen la diversidad biológica (McPherson, 1997;Puerto, 1997). Así, las sabanas son usadas en forma múltiple, porque se combinan actividades forestales, ganaderas, agrícolas y cacería cinegética; se caracterizan por presentar un estrato herbáceo continuo y un estrato arbóreo o arbustivo disperso.Las plantas leñosas en una sabana pueden variar de 1 a 30% (McPherson, 1997).Las sabanas son extensas y económiamente importantes en regiones templadas y tropicales (Scholes y Archer, 1997). En América del Norte las sabanas se distribuyen principalmente en el

Arvenses en cultivos de maíz de temporal en las tres provincias biogeográficas del estado de Aguascalientes, México

“…Para obtener el listado florístico se realizaron 48 inventarios fitoecológicos en el mismo número de sitios de muestreo con cultivo maíz de temporal elegidos de manera dirigida (Castillo-Nonato & Chávez-Mejía 2013) y con previa autorización del dueño, diez por provincia biogeográfica durante el ciclo agrícola 2020, cinco en SMO y CP y ocho en AS durante 2021. Una vez en el sitio de muestreo, se utilizó el método área muestra homogénea de 256 m 2 en orden ascendente (1/64, 1/16, 1/8, 1/4, 1/2, 1, 2, 4, 8, 16, 32, 64, 128 y 256 m 2 ) (Daget & Godron 1982, Sosa-Ramírez et al 2015 y adicionalmente se registraron las especies que se observaron fuera del área de muestreo pero dentro de la parcela (Rivera-Ramírez et al 2021). Además, con el fin de analizar la diversidad de arvenses se muestreó por medio de cuadrantes al azar con base en la técnica usada por Sánchez-Blanco & Guevara-Féfer (2013).…”

Forest seed dispersal by carnivores in temperate forests and dry tropical forests

“…These authors found the seeds of 18 plant species in 384 scats of mammalian carnivores, concluding that carnivores can disperse seeds in abundance and intestinal passages can have varying effects on different plant species, favoring or deteriorating the germination of their seeds, as well as dispersal to and colonization of distant areas and ecosystems. In particular, the Sierra Fría Protected Natural Area (ANP-SF) in the state of Aguascalientes, Mexico is made up of different types of ecosystems, including TF (Sosa-Ramírez et al, 2015) and DTF (Argumedo-Espinoza et al, 2018). The objective of this study was to evaluate the role of carnivorous mammals in the dispersal of seeds in different forest ecosystems, namely temperate forest and dry tropical forest.…”