A study of piedmont scrub adjacent to the Gulf Coastal Plain in the State Nuevo Leon was carried out. Canopy cover values, density, height, frequency, and importance value from all shrub species of the piedmont scrub were recorded in each of the 39 sites sampled. We recorded 233 taxa, including 55 families, 150 genera, and 228 species. Thirty nine of the species define almost 95% of the different vegetation associations of the piedmont scrub. Seven dominant growth forms were recorded, shrubs, trees, rosetophyllous, succulents, herbs, lianas, and parasites. The shrubs are the dominant specie (116 species), followed by trees (39) and shrubby and herbaceous succulents (26). Non-thorny shrubs are the dominant species in the three strata of the piedmont scrub. Based on importance values of the 39 most important species, piedmont scrub was classified by means of cluster analysis. Four main groups and eight plant associations are recognized. We recorded 19 endemic species into the piedmont scrub, 15 herbs, three succulents (small cacti) and one tree, there is not endemic shrubby species in the piedmont scrub. Logging is the main cause of piedmont scrub loss around metropolitan area: Logged areas are converted to human settlements.
Mexico is a megadiverse country, however its tardigrade fauna is poorly known and to date 44 species have been reported from this region. In the present paper, an update of the reported Mexican tardigrades is presented, increasing the number of recorded tardigrades to 55 species (11 new records). Moreover, we describe Milnesium cassandrae sp. nov. from State of Nuevo León in northern Mexico. The new species is most similar to Mil. krzysztofi Kaczmarek & Michalczyk, 2007 and Mil. beasleyi Kaczmarek, Jakubowska & Michalczyk, 2012, but it differs from them mainly by details of the dorsal sculpture and some morphometric characters. We also discuss the taxonomic value of a recently described feature, ‘pseudoplates’, for differentiating the taxa within the genus Milnesium Doyère, 1840. [Zoobank URL: urn:lsid:zoobank.org:act:0684AE18-0510-4F7B-B75D-AE5177FBF2A2]
Resumen: Se muestrearon nueve sitios con bosque mixto de coníferas que presentan al tejo mexicano (Taxus globosa var. floridana) en la Sierra Madre Oriental, en los estados de Nuevo León y Tamaulipas. Se cuantificó área basal, densidad, cobertura, altura y número de especies arbóreas y arbustivas asociadas, así como las variables altitud, exposición, pendiente y pedregosidad. Los bosques estudiados fueron divididos de acuerdo con su distribución en norte y sur para su análisis y compararon mediante una prueba de t. Para cada sitio se calculó el índice de diversidad Shannon-Wiener y se aplicó una prueba de t de Hutcheson para determinar las diferencias en diversidad entre los sitios. Se calculó el valor de importancia de cada especie por sitio y esta información fue evaluada mediante análisis de conglomerados, utilizando sólo aquellas especies con valor de importancia ≥ 5% en al menos uno de los sitios. El área basal y la altura fueron diferentes significativamente entre los sitios norte y sur, y lo mismo se observó para las variables altitud y pendiente; las demás variables no mostraron diferencias significativas con base en la prueba de t. Abstract: Nine sites of mixed-conifer forests where the Mexican yew (Taxus globosa) inhabits in the Sierra Madre Oriental at the States of Nuevo León and Tamaulipas were sampled. We quantified the basal area, density, canopy cover, height and number of plants of the associate species, as well as altitude, topographic aspect, slope, and stoniness. The sampled sites were divided in northern and southern sites according to their distribution in the study area and their attributes were compared with t tests. A Shannon-Wiener diversity index was calculated for each site and a Hutcheson t test was applied to find differences in diversity values between sites. The importance value for each species per site was calculated and the information of the nine forest sites was evaluated by means of cluster analysis, using only those species with importance value of ≥ 5% in at least one site. The t tests showed that both basal area and plant height were different between the northern and southern sites, as were altitude and slope; the other variables showed statistical equality. The higher diversity was found at inaccessible sites such as El Butano and in areas far away from urban zones such as Las Tinajas. The sites without differences regarding their diversity indices are geographically closer to each other. The dendrogram showed that La Camotera and El Rumbadero, along with Potrero had the highest similarity. Abies vejarii subsp. mexicana, Juglans mollis, Quercus rysophylla and Tilia mexicana are the most common species in the forests where Taxus globosa var. floridana inhabitat.
Los bosques de pino (Pinus spp.) de todo el mundo están declinando debido al mal manejo, al cambio climático, incendios y ataques de insectos descortezadores (Dendroctonus spp.). El objetivo de este estudio fue evaluar la abundancia altitudinal y temporal de D. adjunctus y D. brevicomis y su relación con la temperatura y características del rodal. Se establecieron dos transectos altitudinales a partir de 2600 hasta 3300 metros sobre el nivel del mar (msnm), usando trampas para insectos, cada trampa compuesta de ocho embudos, localizadas a intervalos de 100 m de altitud. Los insectos fueron recolectados cada dos semanas desde febrero 2015 a febrero de 2017. Los datos de temperatura y del rodal fueron obtenidos en cada sitio de muestreo. Los resultados indican que D. adjunctus y D. brevicomis fueron más abundantes por arriba de los 3000 msnm durante primavera y verano. La abundancia de descortezadores se correlacionó significativamente con la temperatura, área basal y densidad de los árboles. En conclusión, las características del bosque y las especies de pino presentes en el rodal determinan la abundancia de D. adjunctus y de D. brevicomis en la región.
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