Vegetation patch dynamics and tree diversity in a diverse conifer and oak forest in central Mexico

Abstract

Mexican conifer and oak forests are very diverse, and represent the vegetation type with the highest timber production in Mexico. Yet, there is little knowledge about the relationship of forest recovery and tree diversity in this type of vegetation. In this study, we analyzed the dynamics of vegetation patches over three time periods covering five decades, within an area in central Mexico dominated by conifer and oak forest. We identified vegetation patches, and evaluated their number and changes in patch size and vegetation cover. We also evaluated the composition and structure of the plant canopy in vegetation plots representing different canopy cover classes. Over the three periods studied, the number and total area of patches remained relatively constant, but an increase in canopy vegetation cover occurred in most vegetation patches. Patch canopies were dominated by the long-lived pioneer tree species Juniperus deppeana and the shrub Arctostaphylos pungens. We suggest that forest management in our study region should focus on facilitating the dominance of pines and oaks in sites that have recovered their canopy cover, and to identify the factors inhibiting succession in patches with less than 10 % vegetation cover.

Seed dispersal by carnivores in temperate and tropical dry forests

“…During the study period, we found scats of gray fox, coyote, ringtail, coati, and bobcat, which are associated with seed dispersal in the temperate and the tropical dry forest, while plants dispersed -Núñez et al, 2016). This is the case for A. pungens, the seeds of which were dispersed at a higher average abundance in the scats of gray fox, which corroborate previous findings for the same species (e.g., Rubalcava-Castillo et al, 2020).…”

“…), oak (Quercus potosina), Chihuahua pine or ocote chino (Pinus leiophylla var. Chihuahuana), and twisted leaf pine or pino colorado (Pinus teocote), among others (Díaz-Núñez et al, 2016). On the other hand, the tropical dry forest has an average annual precipitation of 625 mm (Sosa-Ramírez, 1998), and the plant communities are composed of blue myrtle-cactus (Myrtillocactus geometrizans), palo bobo (Ipomea murucoides), kidneywood tree (Eysenhardthya polystachya), torchwood copal (Bursera fagaroides), and palo blanco (Forestiera phillyreoides), among others (Argumedo-Espinoza et al, 2018).…”

“…and Arctostaphylos pungens (Díaz-Núñez et al, 2016). The most common seed dispersal modes found in this type of ecosystem are endozoochory (dispersal through consumption by animals), anemochory (dispersal by wind), and epizoochory (dispersal by adhering to mobile living beings) (Willson et al, 1990).…”

Endozoochorous dispersal of forest seeds by carnivorous mammals in Sierra Fría, Aguascalientes, Mexico

“…These two plateaus are separated by the ravine Cañada de Piletas . Based on pre‐existing maps of the vegetation cover by Díaz‐Núñez et al (), where, for the estimation of forest coverage, a SPOT ® 2013 satellite image of 5 meters resolution was used. The study area was divided into patches or fragments that form continuous mosaics within a landscape and four categories of coverage were established for the landscape classification: 1 = ≤10%, 2 = 11%–30%, 3 = 31%–50%, and 4 ≥50%.…”

“…In Aguascalientes, Mexico, the Área Natural Protegida Sierra Fría (the Sierra Fría Protected Natural Area or ANP‐SF by its Spanish acronym) includes a group of ecosystems belonging to three biogeographic provinces (Sosa Ramírez, Breceda‐Solís, Jiménez‐Sierra, Iñiguez‐Dávalos, & Ortega‐Rubio, ). Díaz‐Núñez, Sosa‐Ramírez, and Pérez‐Salicrup () describe the recovery of these ecosystems since the 1990s, reporting that the pioneer species that present the greatest distribution and colonization of the area postdisturbance are the pointleaf manzanita or pingüica ( Arctostaphylos pungens Kunth; Ericaceae), which is a fire‐adapted plant that thrives in places where events have frequently destroyed holm oak trees (Rzedowski, ), and the checkerbark juniper or táscate ( Juniperus deppeana Steud; Cupressaceae), which is a dioecious species that lives in temperate to semiarid environments and is tolerant to alkaline and nutrient poor soils (Batis, Alcocer, Gual, Sánchez, & Vázquez‐Yánez., C., ; Martínez, ). Both of these plant species act as nurse species to other larger species.…”