Environmental functions of smallholder
farmer land classes in the Zicuirán-Infiernillo
Biosphere Reserve, Mexico
Funciones ambientales de las clases de tierras campesinas: Reserva de la Biosfera Zicuirán-Infiernillo, México
Available online: 2018-05-08
/ pages 265-274
Introduction: There are few cases in which the environmental functions of soils have been
quantitatively evaluated using data from soil profile descriptions.
Objective: The environmental functions of seven peasants land classes (Barrosa, Polvilla, Charanda,
Tocura, Cementante, Polvilla/Barrosa and Polvilla/Charanda) in the Zicuirán-Infiernillo biosphere,
Mexico, were evaluated in order to propose a more rational use of the soils.
Materials and methods: Soil & Environment® software was used to evaluate the soil function in
the water cycle, food and biomass production, nutrient cycle, habitat for flora and fauna, habitat
for human life and torrential rainfall infiltration.
Results and discussion: The Barrosa land class, distributed in the valley, has the most suitable
environmental levels, followed by the Polvilla-Barrosa class with very high capacity in terms of
torrential rainfall infiltration, and the Tocura and Polvilla-Charanda classes with high suitability in
the same environmental function. Next is the Charanda class, suitable for the production of food
and biomass and as a component of the nutrient cycle; finally, with more restricted suitability, in
general terms, there is the Polvilla class that stands out as a flora and fauna habitat.
Conclusion: The Barrosa and Charanda land classes have the greatest potential as food and
biomass producers, and as a component of the nutrient cycle; however, these classes correspond
to the area with the largest human settlements, which could cause problems in the supply of
agricultural and livestock products.
Characterization of four pinyon pine forests in the state of Zacatecas, Mexico
Caracterización de cuatro bosques de pino piñonero del estado de Zacatecas, México
Available online: 2018-05-28
/ pages 275-296
Introduction: Communities dominated in the canopy by pinyon pines harbor species richness and have complex physiognomy because they form an ecotone between arid and temperate zones.
Objectives: To describe the floristic attributes that distinguish four communities dominated by pinyon pines; define units based on floristic composition and structure; and determine the influence of edaphic factors.
Materials and methods: The flora of four communities in the state of Zacatecas was recorded. The arboreal and shrub vegetation was analyzed quantitatively using the point-centered quarter technique. Semi-realistic physiognomic profiles were made for each site. The groups resulting from cluster analysis were ordered with edaphic factors through a canonical correspondence analysis.
Results and discussion: Floristic richness was 244 species; each community contains between 60 and 80 species. Structurally, three physiognomic variants were recorded: forests dominated by Pinus cembroides Zucc.; association of P. cembroides - P. cembroides var. bicolor Little; and forest dominated by P. maximartinezii Rzed. The pH, electrical conductivity and soil texture have a great influence on the structure and plant composition of the communities. The P. cembroides - P. cembroides var. bicolor association and its accompanying species develop in nutrient-poor soils, while P. maximartinezii forests prefer shallow soils.
Conclusion: The floristic similarity among communities was low. Each community must be managed differently, meeting the particular requirements of the species that develop there.
Economic valuation of the calden (Prosopis caldenia Burkart) forest in the south of Córdoba, Argentina
Valoración económica del bosque de caldén (Prosopis caldenia Burkart) en el sur de Córdoba, Argentina
Available online: 2018-06-05
/ pages 297-312
Introduction: The native forest of calden is a natural ecosystem that produces valuable ecosystem goods and services for society; however, it has been replaced for the production of commercial, agricultural and livestock goods.
Objective: To estimate the economic value of a conservation program for ecosystem services of the remnant of the native calden (Prosopis caldenia Burkart) forest in the south of the province of Córdoba, Argentina.
Materials and methods: The study area corresponds to a remnant forest of 37 648 ha. The willingness to pay (WTP) was obtained from a contingent valuation survey; 361 questionnaires were applied. The sampling unit was the household. A multistage cluster sampling was used in the city of Río Cuarto and a simple random sampling in Villa Huidobro.
Results and discussion: The estimated WTP showed goodness of fit and most of the estimated coefficients were statistically significant (P < 0.05) and consistent with what was theoretically expected. The WTP increases with household income and decreases as the consulted amount of money to pay increases. The average WTP for a conservation program of the native calden forest is 52 ± 8 ARS (11.45 ± 1.76 USD) monthly per household.
Conclusion: The majority of the urban population of southern Córdoba does not use forest ecosystem services; however, they are willing to pay to maintain or increase forest ecosystem services.
Bandwidth selection for kernel density estimation of forest fires
Selección de ancho de banda para la estimación de densidad kernel de incendios forestales
Available online: 2018-06-27
/ pages 313-327
Introduction. The mapping of areas with higher forest fire density can be developed through kernel density estimation, which requires the selection of a function and bandwidth (h). The h value, when defined by subjective (visual) processes, will depend on the knowledge and experience of the person making the selection.
Objective: To propose a statistical alternative, based on forest fires information (2005-2013) from Jalisco, Mexico, for the selection of h as support for kernel density estimation.
Materials and methods: A total of 13 h values were defined using seven techniques. The h value was selected using the following statistics: root mean square error, root mean integrated squared error, coefficient of variation and comparative percentage.
Results and discussion: The h values obtained with the techniques analyzed were between 2 550 and 41 906 m. There was great variation in the results; the range between the maximum and the minimum value was 39 356.34 m with an average of 10 936.74 ± 9 955.04 m. The above implies that there is no single and universal process for all cases. According to the validation criteria, the statistically most adequate h value is between 5 300 and 5 900 m; the closest result was obtained with the mean random distance technique (5 395 m).
Conclusion: It is possible to select h under a practical statistical perspective, avoiding the use of subjective criteria.
Potentially toxic minerals in environmental liabilities in Noria de Ángeles, Zacatecas
Minerales potencialmente tóxicos en pasivos ambientales de Noria de Ángeles, Zacatecas
Available online: 2018-06-27
/ pages 329-337
Introduction: Sites polluted by mining activity represent a risk to human health.
Objective: To determine the concentration of toxic minerals (Hg, Pb, Cd and As) in two environmental liabilities (ELs) in Noria de Ángeles, Zacatecas.
Materials and methods: Soil samples from two ELs and a reference site were taken based on NMX-AA-132-SCFI-2006; in addition, a spring and waterbodies adjacent to or on the ELs were sampled, in accordance with NOM-230-SSA1-2002. Toxic elements in soil and water were analyzed in accordance with NOM-147-SEMARNAT/SSA1-2004 and NOM-127-SSA1-1994, respectively. The concentrations of elements in the soil were subjected to an analysis of variance and Tukey’s range test (P < 0.05).
Results and discussion: The Hg concentration was higher (P < 0.05) in the ELs than in the reference site, but it did not exceed the maximum permissible limits (MPL) established by the standards. The Cd and As in the soil of the ELs and reference site exceeded the MPL, and the Pb only in the ELs. It is deduced that the As has a mainly geological origin, since its content in the reference site was higher than the recent EL. In the waterbodies, the Pb, Hg, Cd and As concentrations were much higher than the MPL.
Conclusion: The Pb, Cd and As in the ELs, and the Pb, Cd, Hg and As in the waterbodies pose a risk to the health of the residents of Noria de Ángeles, Zacatecas.
Woody fuel load in coastal wetlands of the La Encrucijada Biosphere Reserve, Chiapas, Mexico
Carga de combustibles leñosos en humedales costeros de la Reserva de la Biosfera La Encrucijada, Chiapas, México
Available online: 2018-07-07
/ pages 339-357
Introduction: The quantity and quality of forest fuels determine the frequency, intensity and impact of a fire. Despite the ecosystem services they provide, little is known about coastal wetlands such as mangroves and tropical freshwater forested wetlands.
Objective: To determine the woody fuel load in wetlands of the La Encrucijada Biosphere Reserve (EBR).
Materials and methods: Woody fuels were quantified in three sites where there is an association of mangroves and tropical freshwater forested wetlands. Four sampling units were established by vegetation type at each site. The planar intersect technique was adapted for this evaluation. The fuel load was quantified and compared by type of vegetation, site and diameter class of the woody material.
Results and discussion: Tropical freshwater forested wetlands accumulated dead fuels in a range from 63.19 to 151.87 t·ha-1, while mangroves accumulated between 88.81 to 152.38 t·ha-1; the load difference was not statistically significant (F = 1.05; P = 0.31). Regarding the diameter class, the fine fuel loads (from 0.01 to 0.60 cm) were significantly different among the mangrove sites (F = 3.05; P = 0.04), and the medium fuels (from 2.51 to 7.50 cm) were different among the swamp sites (F = 9.93; P = 0.006).
Conclusion: The quantification of forest fuels was possible in coastal wetlands, such as mangroves and tropical freshwater forested wetlands, finding loads up to three times higher than in other temperate zone ecosystems. The information obtained will support the prioritization of fire-prone areas.
Relationship of rootstock xylem anatomy with the initial growth of ‘Tahiti’ lime (Citrus x latifolia Tanaka ex Q. Jiménez)
Relación de características anatómicas del xilema de portainjertos con el crecimiento inicial de lima persa ‘Tahiti’ (Citrus x latifolia Tanaka ex Q. Jiménez)
Available online: 2018-08-18
/ pages 359-370
Introduction: Rootstock diversification arises as a consequence of the appearance of diseases and the need to improve the yields and productive efficiency of orchards.
Objective: To establish the relationship between the anatomical characteristics of the stem of four citrus rootstocks and the initial growth of ‘Tahiti’ lime (Citrus x latifolia Tanaka ex Q. Jiménez).
Materials and methods: The rootstocks ‘Volkamer’ lemon (C. volkameriana Tenn. & Pasq.), sour orange (Citrus aurantium L.), ‘Flying Dragon’ trifoliate orange (Poncirus trifoliata var. monstrosa [T. Ito] Swingle) and ‘Rubidoux’ trifoliate orange (P. trifoliata [L.] Raf.) were evaluated. The degree of correlation between seven characteristics of the initial growth of the graft and eight characteristics of the secondary xylem of the stem of the rootstocks was established.
Results and discussion: Sour orange and ‘Volkamer’ lemon showed more vigorous growth; the variables evaluated were 23 to 70 % higher than with ‘Rubidoux’ and ‘Flying Dragon’. The sour and ‘Volkamer’ rootstocks had xylem vessels of greater area and lower density, as well as greater fiber length and xylem radiuses; these characteristics were correlated with higher shoot length and diameter values, growth rate, number of leaves and leaf area of the graft shoot. Smaller vessel size but higher density caused the opposite effect on graft growth.
Conclusion: Vessel density, diameter and length, and fiber length showed higher correlations with the growth variables, so they can be used as prediction characteristics for graft growth.
Reconstruction of historical precipitation (1877-2014)
for the southwest of the Sierra Gorda
Biosphere Reserve, Querétaro, Mexico
Reconstrucción de la precipitación histórica (1877-2014) para el suroeste de la Reserva de la Biosfera Sierra Gorda, Querétaro, México
Available online: 2018-07-20
/ pages 371-386
Introduction: Historical analysis of climate variability represents a first approach to know the
recurrence of events such as droughts and floods, as well as to infer possible climate trends. This
study is the first historical analysis in the Sierra Gorda Biosphere Reserve (SGBR).
Objectives: To develop dendrochronological series with the ring width of Pinus greggii Engelm.
ex Parl. and P. montezumae Lamb., determine their potential to reconstruct rainfall variability, and
reconstruct, minimally, precipitation variability and its relationship with the El Niño Southern
Oscillation (ENSO) for the last century.
Materials and methods: In the southwest of the SGBR, 87 samples were extracted from 29 trees,
of which 15 (45 rays) corresponded to P. greggii and 14 (42 rays) to P. montezumae. The growths were
dated using dendrochronological techniques.
Results and discussion: The generated chronology, composed of 138 years (1877-2014), was
significantly correlated (P < 0.01) with the January-May rainfall. The reconstruction of the winter-
spring seasonal precipitation variability indicates that there is interannual and interdecadal
variation. Four severe droughts were identified (1887, 1951-1956, 1969-1972 and 2012) and two
periods with excellent precipitation (1962-1967 and 1983-1993). The severest droughts in the
southwest of the SGBR synchronize with extreme events reconstructed for the north of the country
with a 50-year recurrence interval.
Conclusion: Pinus greggii and P. montezumae responded significantly to the precipitation of the
winter-spring period, which allowed the reconstruction of rainfall variability over a period of 138
years. Variability has been significantly modulated by ENSO.
Above-ground biomass and carbon sequestration in mangroves in the arid area of the northwest of Mexico: Bahía del Tóbari and Estero El Sargento, Sonora
Biomasa aérea y captura de carbono en manglares de la zona árida del noroeste de México: Bahía del Tóbari y estero El Sargento, Sonora
Available online: 2018-07-30
/ pages 387-403
Introduction: Mangroves are the largest carbon sinks and contribute to mitigate the effects of global climate change. Objective: To estimate the above-ground biomass (AB) of El Sargento estuary and Bahía del Tóbari, to compare the carbon stocks between both places.
Materials and methods: Measurements were taken from May 2014 to November 2015. The species were identified, and tree diameter, height and canopy cover were measured in 16 plots of 10 x 10 m. The AB was estimated with allometric equations and was related to the carbon content by the factor 0.5. The statistically significant differences between the carbon contents of both study sites were detected with the T test for independent samples.
Results and discussion: The AB in El Sargento estuary was estimated between 108.1 and 316.78 Mg∙ha-1 with predominance of Laguncularia racemosa (L.) Gaertn (60 %); in Bahía del Tóbari, the AB varied between 72.12 and 130 Mg∙ha-1, prevailing Avicennia germinans (L.) L. (83.4 %). In both sites Rhizophora mangle L. was found marginally. Total carbon storage was greater in El Sargento (with a range of 54.1 to 158.4 Mg C∙ha-1) compared to Bahía del Tóbari (36.1 to 65.5 Mg C∙ha-1); the difference was statistically significant (F = 0.01; P = 0.02).
Conclusion: The difference in the carbon reserves of the study sites is related to the good species development and diversity of a pristine environment (El Sargento), compared to another severely impacted environment (Bahía del Tóbari).
Characteristics of oil palm trunks for rearing of Rhynchophorus palmarum (Coleoptera: Curculionidae) in the Peruvian Amazon
Características de los troncos de palma aceitera para la crianza de Rhynchophorus palmarum (Coleoptera: Curculionidae) en la Amazonía peruana
Available online: 2018-07-31
/ pages 405-414
Introduction: In the Peruvian Amazon, felled oil palm (Elaeis guineensis Jacq.) trunks are usually
burned to prevent the increase of these residues. These trunks are also used for the rearing of
Rhynchophorus palmarum (Linnaeus, 1758) Csiki E., 1936 larvae, which locals use as a food source.
Objective: To establish the relationship between the characteristics of the cut E. guineensis trunks
and the rearing of R. palmarum larvae.
Materials and methods: The research was conducted in three districts (San Pedro-Campo Verde,
Tahuayo-Neshuya and Maronal-Curimaná) of the department of Ucayali, Peru. The correlation
between the number of R. palmarum larvae and the length and diameter of the trunk’s central
cylinder was analyzed using the Spearman coefficient (rs
). In addition, the soil texture class was
determined and the correlation with the number of larvae was established.
Results and discussion: The length and diameter of the felled oil palm trunks were different
(P < 0.05) in the three sites evaluated. There is no relationship between the number of R. palmarum
larvae and the length and diameter of the trunk segments. By contrast, the soil’s clay loam texture
is positively correlated with the number of larvae (rs = 1.00, P < 0.01). The number of larvae was
higher in the Tahuayo-Neshuya district samples (145.67 ± 39.67; P < 0.0001).
Conclusion: Characteristics of the oil palm trunk are not associated with the development of
Forest fringe communities of the southwestern Iberian Peninsula
Comunidades de orla forestal en el suroeste de la península ibérica
Available online: 2018-08-24
/ pages 415-434
Introduction: Forest and pre-forest fringe communities in the southwest of the Iberian Peninsula are semi-shaded perennial herbs of external fringe and open areas of evergreen or semi-deciduous woodlands and their pre-forestry mantles, linked to the Stachyo lusitanicae-Cheirolophenion sempervirentis suballiance.
Objective: To evaluate the chorology, ecological features and floristic circumscription of the forest fringe communities of the southwestern Iberian Peninsula.
Materials and methods: Forest fringe communities adscribed to the Stachyo lusitanicae-Cheirolophenion sempervirentis suballiance were analysed, using phytosociological approach (Braun-Blanquet methodology) and numerical analysis (hierarchical cluster analysis).
Results and discussion: The statistical and phytosociological analysis of six formerly described associations and the samples of this study lead us to propose a new forest fringe association: Picrido spiniferae-Cynarietum algarbiensis, dominated by Cynara algarbiensis Coss. ex Mariz. This forest fringe community is characteristic of the thermomediterranean to mesomediterranean, lower sub-humid bioclimate and occurs in the potential areas of the Quercus suber L. forests (Lavandulo viridis-Quercetum suberis), mainly in the Monchique Sierran District.
Conclusion: The statistical and phytosociological analysis were useful in the evaluation of forest fringe communities in the southwest of the Iberian Peninsula. Regarding the proposal of the new association Picrido spiniferae-Cynarietum algarbiensis, it is important to develop management strategies for the preservation of the endemic C. algarbiensis.
Keywords: Stachyo lusitanicae-Cheirolophenion sempervirentis suballiance; phytosociology; Cynara algarbiensis; endemic flora; cluster analysis