Efectos del sitio y la condición de agostadero en la densidad de hormigueros de escamoles (Liometopum apiculatum Mayr)

Abstract

El efecto de la condición de agostadero en la densidad de hormigueros de la hormiga de escamoles (Liometopum apiculatum Mayr) se evaluó en tres sitios diferentes (favorable, regular y desfavorable), en un espacio dividido en dos patrones contrastantes de aprovechamiento y régimen de tenencia comunal (ejido) y privada (rancho) en Charcas, San Luis Potosí, México. La vegetación se midió utilizando el método de cuadrantes centrados en un punto, espaciados sobre transectos; en cada cuadrante se midió el individuo más próximo al punto correspondiente a cada estrato de la vegetación y se registró la distancia al hormiguero más cercano (si existía). Las especies se agruparon de acuerdo con su valor forrajero (deseables, menos deseables e indeseables) y, mediante estimaciones de densidad y biomasa volumétrica, los grupos se contrastaron con un análisis tabular y estadístico descriptivo. La superficie del suelo se evaluó con el método de líneas de intercepción en la proporción de cobertura basal viva y muerta (mantillo), suelo desnudo, rocas, caminos de hormigas y heces. La densidad más alta de los hormigueros (14·ha-1) se registró en el sitio favorable del rancho (mejor condición de agostadero). Con base en la información registrada se encontraron diferencias en la densidad de hormigueros entre sitios de agostaderos contiguos, lo cual a su vez es alterado severamente por la condición de los mismos.

Traditional and Updated Evaluation of the Rangeland Site and Condition in the Semiarid Scrub of the High Plateau

“…The growing problem of rangeland deterioration in arid regions was also recognized by Lara-Juárez et al (2016) and Bikila and Tessema (2017). Grouping the species registered during the surveys according to the forage value and scoring them based on the literature, direct observation, and opinions of local people was suitable for determining structural changes in the vegetation due to use patterns and in accordance with relevant antecedents for similar conditions (Solomon et al, 2007;Lara-Juárez et al, 2016;Bikila and Tessema, 2017;Aguirre-Rivera et al, 2020) and, in general, for grazing spontaneous vegetation.…”

“…Also, some of the variables evaluated in our study coincide with those applied by Solomon et al (2007) in their study of the perception of degradation of the rangelands in southern Borana, Ethiopia; the principal indicators of deterioration were a decrease in abundance of desirable Poaceae, an increase in undesirable woody species, and an increase in the portion of bare soil. Lara-Juárez et al (2016) used the same technique to evaluate rangeland condition in another study to determine the relationship between rangeland condition and the presence of escamole ant nests (Liometopum apiculatum) in a rangeland shared by a private ranch and an adjacent ejido in Charcas, San Luis Potosí, although they only classified rangeland condition qualitatively as better, worse, and intermediate. Mellink and Valenzuela (1995) used the concept of rangeland condition qualitatively as well, categorizing their findings as better or worse.…”

“…It is worth mentioning that the soil surface of the rangeland sites on the LS ranch was outstanding, with the least amount of bare soil and the most vegetation of the three ranches studied. About the information on actual soil cover, the variables "bare soil", followed by the portion of soil covered by "vegetation" (equivalent to the structural attribute "basal area"), were those that were more closely related to condition, in accordance with its antecedents (Lara-Juárez et al, 2016;Bikila and Tessema, 2017;Aguirre-Rivera et al, 2020). Multivariate ordering of the attributes evaluated in the surveys Of the multivariate analysis applied to the variables vegetation and soil cover evaluated at each rangeland site, only the representative value of the first two ordering axes provided significant information for interpretation.…”

“…;Bikila and Tessema, 2017;Aguirre-Rivera et al, 2020) Pinos-Rodríguez et al (2013). also recorded 38 species consumed by goats in communal rangelands of Villa de Guadalupe, San Luis Potosí, whileLara-Juárez et al (2016), in their study of escamole ants, found 35 species in the "Siete Vueltas" paddock of the LS ranch and only 22 in the ejido Francisco I. Madero. The two properties were separated by a borderline fence and shared the same rangeland sites, and sampling was based on the same sample size.…”

“…Juárez et al, 2016;Negrete-Sánchez et al, 2016), as compared with private ranches where the owners can more easily make decisions to adjust stocking rate and spatial distribution.…”