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It is not clear whether any particular type of forest land ownership is better than another regarding the quality of natural resource management. However, some researchers have found that communal ownership is efficient for this purpose, providing all members agree to establish operational rules and apply these in an atmosphere of cordiality and respect. In Mexico, 26% of the forests are privately owned, 4% are publicly owned and the remaining 70% are owned and managed by rural communities known as Ejidos and Comunidades . Studies of how forests and forest management may differ in relation to the type of land ownership in Mexico are scarce. Research on differences in tree species diversity in Mexican forests is desirable because species diversity is an important index in community ecology and may be affected by forest management. Moreover, tree species diversity is used as a biodiversity indicator in various monitoring schemes for sustainable forest management. In order to help resolve the lack of information regarding possible differences in forest management in relation to land ownership type in Mexico, the objectives of this study were as follows: (1) to identify groups of climatic, physiographical and social conditions that are almost homogeneous but widely separated from each other, and (2) to determine whether the type of forest land ownership affects tree species diversity within each group. Vegetation-related data on 1592 plots in a forest area of about 6.33 million hectares were obtained from the Mexican National Forest and Soil Inventory. We used k -means clustering algorithms and the Affinity Propagation clustering, in an attempt to compare tree species diversity in communally and privately owned land. Finally, we used the Kruskal–Wallis rank sum test and a permutation test to compare the mean values of the tree species diversity in each cluster of similar, special conditions identified. There were no significant differences in the mean values of tree species diversity between the two types of forest land ownership. Thus, the study findings did not support the hypothesis that tree species diversity tends to be higher in communally owned forests than in the privately owned forests in the study area. Future research is needed to address the following: (1) the effect of land ownership regime on forest fragmentation, (2) agreements among diverse stakeholders about the type of benefits derived, and (3) improvement of public policies aimed at cost-effective sustainable forest management, considering land ownership. [ABSTRACT FROM AUTHOR]

Long-term, multi-decade research on planted tree survival in urban settings is sparse. One understudied urban environment is highway rights-of-way (ROW), lands adjacent to high-speed, unsignalized roadways. We conducted a re-inventory of tree planting cohorts in northern Illinois, U.S. on a 48 km-long highway near Chicago which were 10-, 21-, and 30-years old to evaluate long-term patterns of survival and diversity. Using each randomly selected planting site along the highway as a unit of observation and analysis, we compared the number of trees documented in record drawing to the number of trees currently alive to determine percent survival. We evaluated 224 planting sites which originally contained 2944 trees and collected data about the planting site location. For the oldest cohort, 26% of trees were still alive in 2018 (median survival by species = 16%, Q1 = 0%, Q3 = 48%), while 31% of the 21-year-old cohort (med. = 6%, Q1 = 0%, Q3 = 47%) and 86% of the 10-year-old cohort were still alive (med. = 85%, Q1 = 74%, Q3 = 96%). The survival of the 21- and 30-year-old cohort matches urban tree survival estimates by other researchers, while the 10-year-old survival is higher than expected. The only planting location characteristic that significantly affected survival was traffic islands (areas between the highway and entrance/exit ramps). Species with low drought tolerance were less likely to be alive for the 30-year-old cohort. Waterlogging tolerant species were more likely to be alive in the 10-year-old cohort. Since some species in the 21- and 30-year-old cohorts had very low survival, the tree species richness and diversity s in study areas declined between the initial record drawings and reinventory. This study demonstrates the challenges of maintaining long-term survival and diversity in the highway ROW and emphasizes the importance of species selection. [ABSTRACT FROM AUTHOR]

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• Urban school yards have potential to support biodiversity in urban landscapes. • Exotic species are homogenized in urban school yards. • Diversity of indigenous species is related to school yard area. Previous studies have clearly outlined the importance of urban green spaces such as golf courses, urban gardens and street sides in urban ecosystem functioning. To date little has been done to consider the role of urban school yards in biodiversity conservation in Southern Africa. Our study therefore investigated the role of urban school yards in biodiversity conservation across an urban gradient in the city of Harare, Zimbabwe. Ten schools were randomly selected from each stratum, low, medium and high density suburbs. School yards were surveyed for herbs (garden flowers) and woody plants (trees and shrubs). For α diversity, species richness, Shannon and Simpson diversity indices were computed using the Hill numbers. Variation in species composition among schools was assessed using beta diversity (β SOR) and its components (β SIM and β SNE). A total of 120 tree species belonging to 43 families and 89 garden flowers belonging to 41 families were identified and recorded in school yards from the different suburb densities. Schools in medium density suburbs had highest species richness, Shannon, Simpson and beta diversity indices for indigenous trees compared with those in the low and high density suburbs. For garden flowers, there was no variation in species richness, Shannon, Simpson and beta indices across school yards from low, medium and high density suburbs. Our results demonstrate the important role of urban school yards in biodiversity conservation in general, though there is species homogenization of garden flowers and exotic trees across the urban landscape. [ABSTRACT FROM AUTHOR]