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| 1 | 人为干扰对雅安苍坪山公园桉树人工林物种多样性和生物量的影响显示文摘【目的】揭示不同人为干扰强度对桉树Eucalyptus grandis人工林物种多样性和生物量的影响。【方法】以四川省雅安市苍坪山公园桉树人工林为研究对象,采用典型样地法,设置12块20 m×20 m不同干扰程度的样地,对林内物种组成、物种多样性水平(丰富度指数D、Shannon-Wiener指数H、Simpson优势度指数H’、Pielou均匀度指数Jsw)和植物层生物量进行调查研究。【结果】共调查到维管植物87种,隶属55科82属,桉树人工林物种数随着干扰的加强而减少;乔木层与草本层D、H、H’随着干扰强度的增加而降低,灌木层D、H、H’在中度干扰下达到最大值,乔木层的D、H变化差异显著(P<0.05)。随着干扰强度的增加,植物各层生物量呈不同变化趋势:中度干扰下乔木层蓄积量(12.01m^(3)·hm^(-2))最高;轻度干扰下灌木层生物量(394.533 kg·m^(-2))和草本层生物量(359.680 g·m^(-2))最高。乔木层D、草本层H’与草本层地上生物量和生物总量呈显著正相关(P<0.05);草本层Jsw与草本层生物总量呈显著正相关(P<0.05)。【结论】适度的干扰会促使桉树人工林物种多样性和生物量增加;物种多样性和生物量的关系受人为干扰和自然条件而改变,没有固定关系。 | 曾洪 陈聪琳 喻静 向琳 孙一淼 胡明玥 郝建锋 | 2021 | 浙江农林大学学报2021，38，2： | 5 |
| 2 | Influence of climatic conditions,topography and soil attributes on the spatial distribution of site productivity index of the species rich forests of Jalisco,Mexico显示文摘This paper presents an approach based on field data to model the spatial distribution of the site productivity index(SPI)of the diverse forest types in Jalisco,Mexico and the response in SPI to site and climatic conditions.A linear regression model was constructed to test the hypothesis that site and climate variables can be used to predict the SPI of the major forest types in Jalisco.SPI varied significantly with topography(elevation,aspect and slope),soil attributes(pH,sand and silt),climate(temperature and precipitation zones)and forest type.The most important variable in the model was forest type,which accounted for35%of the variability in SPI.Temperature and precipitation accounted for 8 to 9%of the variability in SPI while the soil attributes accounted for less than 4%of the variability observed in SPI.No significant differences were detected between the observed and predicted SPI for the individual forest types.The linear regression model was used to develop maps of the spatial variability in predicted SPI for the individual forest types in the state.The spatial site productivity models developed in this study provides a basis for understanding the complex relationship that exists between forest productivity and site and climatic conditions in the state.Findings of this study will assist resource managers in making cost-effective decisions about the management of individual forest types in the state of Jalisco,Mexico. | Adel Mohamed Robin M.Reich Raj Khosla C.Aguirre-Bravo Martin Mendoza Briseo | 2014 | Journal of Forestry Research2014，25，1： | 1 |
| 3 | Differentiated payments for environmental services schemes: A methodology proposal显示文摘Payment schemes for environmental services face serious budget constraints in Mexico. Payments are equally distributed among forest owners, and the governmental agencies that make payments to beneficiaries do not evaluate the amount of environmental services produced by forested areas. This lack of evaluation could lead to economic and environmental deficiencies that restrict the possible benefits of such programmes. In general, these programmes do not achieve their conservation objectives, and local beneficiaries are not involved in the design or application of these programmes. Similarly, the Payments for Hydrological Environmental Services(PHES) programme of the State of Mexico, Mexico, makes equal payments to beneficiaries of forested areas considering tree density. The objective of the present work was to create a methodology for determining differentiated payments schemes for hydrological environmental services, prioritising areas that contribute the most to groundwater recharge and promote the participation of society. In the Nevado de Toluca Natural Protected Area, the environmental criteria of forest type, tree density and aquifer overexploitation as well as social participation were considered in a multi-criteria analysis implemented in a Geographic Information System. A methodology was developed to determine differentiated payments based on specific forest characteristics that influence the potential capacity of forests to recharge groundwater reserves in addition to the level of social participation. In particular, social participation is key as it could ensure the viability of PHES programmes as conservation alternatives in forested areas with high groundwater recharge potential. | Carlos R.AGUILAR-GóMEZ Sergio FRANCO-MAASS Tizbe T.ARTEAGA-REYES | 2018 | Journal of Mountain Science2018，15，8： | 0 |
| 4 | Identification of Arceuthobium globosum using unmanned aerial vehicle images in a high mountain forest of central Mexico显示文摘The identification of forests infested by parasitic plants is important for the design of appropriate control and prevention strategies.Satellite images and geographic information systems are commonly used to analyze the presence of pest and parasitic plants in the forests.However there is a need for finer resolution.In the last decade,the use of unmanned aerial vehicles has become increasingly common for capturing aerial images(<10 cm per pixel).The objective of the study was to obtain RGB values(Red,Green and Blue)through the colorimetric ranges for use in identification of Yellow Dwarf Mistletoe(YDM)(Arceuthobium globosum)in aerial images taken in a forest of central Mexico via a programmed algorithm.Three tonalities of YDM were classified according to its phenological stages,viz.green(young stage),yellow(adult stage),and brown(senescence stage),considering two light intensities,sunny and cloudy.Non-parametric tests were used in statistical analyses.The Spearman test showed significant negative correlation(p<0.001)between phenological stage and colour,indicating that lower RGB values were associated with greater age.The differences between groups were analysed using Kruskal–Wallis(p<0.01)and Mann–Whitney tests(p<0.01).The applied algorithm identified the presence and predominant colours of YDM according to its phenological stage. | Luis A.Leon-Banuelos Angel R.Endara-Agramont William Gomez-Demetrio Carlos G.Martınez-Garcıa E.Gabino Nava-Bernal | 2020 | Journal of Forestry Research2020，31，5： | 0 |
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