scholarly journals Avocado Cover Expansion in the Monarch Butterfly Biosphere Reserve, Central Mexico

Conservation ◽  
2021 ◽  
Vol 1 (4) ◽  
pp. 299-310
Author(s):  
Jesús Eduardo Sáenz-Ceja ◽  
Diego Rafael Pérez-Salicrup

Avocado cultivation has reduced the extent of forest ecosystems in central Mexico, even in natural protected areas such as the Monarch Butterfly Biosphere Reserve (MBBR) where information on the extent and expansion dynamics of avocado cover is scant. This study aimed to identify avocado plantations within the MBBR through photo interpretation for the 2006–2018 period. Change rates of the avocado cover extent were calculated for the northern, central, and southern zones of the MBBR, and topographic attributes such as elevation, soil type, slope, and slope aspect were identified. A total extent of 958 ha is covered by avocado plantations within the MBBR. The southern zone hosted the largest area under avocado cultivation (570 ha), but the northern zone had the highest change rate between 2006 and 2018 (422%). Most avocado orchards have been established mainly in Acrisol soils, south-facing slopes, on steep hillsides, and in elevations between 2050 and 2800 m. The conversion from traditional agricultural lands has been the main mechanism for the establishment of avocado orchards. However, 40 ha under avocado cultivation derived from deforestation, mainly in the central zone. The expansion of avocado plantations could trigger environmental impacts, even threatening the overwintering habitat and the migratory phenomenon of the monarch butterflies.

2016 ◽  
Vol 38 ◽  
pp. 103-116 ◽  
Author(s):  
Teodoro Carlón Allende ◽  
Manuel E. Mendoza ◽  
Diego R. Pérez-Salicrup ◽  
José Villanueva-Díaz ◽  
Antonio Lara

Author(s):  
Gerardo Guzmán-Aguilar ◽  
Aglaen Carbajal-Navarro ◽  
Cuauhtémoc Sáenz-Romero ◽  
Yvonne Herrerías-Diego ◽  
Leonel López-Toledo ◽  
...  

2003 ◽  
Vol 17 (2) ◽  
pp. 367-379 ◽  
Author(s):  
Luis A. Bojorquez-Tapia ◽  
Lincoln P. Brower ◽  
Guillermo Castilleja ◽  
Salvador Sanchez-Colon ◽  
Mariano Hernandez ◽  
...  

2019 ◽  
Vol 99 (7) ◽  
pp. 1547-1555
Author(s):  
Pablo Hernández-Alcántara ◽  
Ismael Narciso Cruz-Pérez ◽  
Vivianne Solís-Weiss

AbstractThe present study is the first attempt to describe beta-diversity patterns in polychaetes of the Caribbean Sea, analysing depth changes in species composition of the Eunicida and Amphinomida inhabiting dead coral in Chinchorro Bank, southern Mexican Caribbean. In April 2008, dead coral fragments were collected by scuba diving in eight stations along two bathymetric gradients (4–9 m and 7–16.2 m depth); 755 individuals from 53 species of the families Amphinomidae, Dorvilleidae, Eunicidae, Lumbrineridae, Oenonidae and Onuphidae were identified. The highest number of species (32) and individuals (514) were found in the family Eunicidae. The Northern transect harboured 36 species, on average 18.75 ind. L−1, which decreased linearly with depth; the Central transect had 43 species, on average 19.01 ind. L−1, which increased at middle depths. The species inhabiting both these zones were moderately different (βsor = 0.603): 49.06% of the fauna occurred on both transects, but the components of beta-diversity, turnover and nestedness, displayed distinct patterns: in the Northern one replacement was the dominant factor (βsim = 0.3–1; βnes = 0–0.091), practically representing all faunal differences (βsor = 0.391–1); in the Central, dissimilarity due to nestedness increased (βnes = 0.031–0.829), mainly at the shallowest stations, but from 5 m depth, beta-diversity was almost completely explained by species replacement (βsim = 0.417–0.5; βnes = 0.031–0.318). Faunal differences were mostly related to higher abundances of Lysidice caribensis, Eunice goodei and Lumbrineris floridana in the Northern zone, and Lumbrineris perkinsi, Nicidion obtusa, Lysidice caribensis, Lumbrineris floridana, Lysidice unicornis and Eunice mutilata in the Central zone.


2010 ◽  
Vol 33 (2) ◽  
pp. 175
Author(s):  
Ma. Luisa España-Boquera ◽  
Philippe Lobit ◽  
Vilma Castellanos-Morales

Chlorophyll is an essential element of photosynthesis and its content in plant leaves indicates their photosynthetic capacity as well as the presence of stress or diseases. The purpose of this work was to evaluate the feasibility of estimating chlorophyll content in the Monarch Butterfly Biosphere Reserve forest (Sierra Chincua sanctuary, México) based on vegetation indices calculated by using hyperspectral reflectance measurements of plant leaves. This study focused on oyamel (Abies religiosa L.) which is the main tree specie of this area. Leaf samples were taken on 140 trees and analyzed for chlorophyll a and b, nitrogen and carbon content. The hyperspectral reflectance spectra were measured on each sample and different vegetation indices were calculated. Results showed that the indices best correlated with chlorophyll content were the red edge position index (r = 0.531) and the red edge position chlorophyll reflectance index (r = 0.506), followed by the MERIS terrestrial chlorophyll index (r = 0.497) and the green chlorophyll reflectance index (r = 0.472). Although there was a significant correlation between nitrogen and chlorophyll content, none of the indices studied here correlated with nitrogen content. The influence of various environmental factors (altitude, slope, vegetation density and aspect) on leaf composition (nitrogen, carbon chlorophyll content and chlorophyll a/b ratio) and on the vegetation indices was studied. Environmental factors had an influence on both leaf composition and vegetation indices. Chlorophyll and nitrogen content were influenced mostly by the altitude and slope of the site while vegetation indices were affected mostly by its orientation.


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