Dataset about Mexico's forest diversity: Site locations of tree species, wood densities, and geographic database of forest-vegetation provinces.

A dataset about three topics is provided, as a follow-up to the article "Mexico's forest diversity: common tree species and proposed forest-vegetation provinces" by Ricker et al. [1]. Firstly, 6927 site locations are provided for 22,532 trees of 1452 species. Secondly, measurements of basic wood-densities are reported for 779 tree species, obtained from 5256 trunk-core samples from Mexico's national forest inventory, and ranging from 0.05 to 0.93 g/cm3. Third, the data and maps of the forest-vegetation provinces from [1] were updated with the new cartography of Mexico's vegetation and land use (base year 2018). The maps are available now in an adjusted presentation as a shapefile-set for ArcGIS, as well as map-package and image files.

How to Extract Climate Variability from Tree-Rings.

Tree rings have been used to reconstruct climatological variables in many locations around the world. Moreover, tree-rings can provide valuable insights into climatic variability of the last few centuries and, in some areas, several millennia. Despite the important development, that dendrochronology has had in recent decades to study the dendroclimatic potential of a large number of species present in different ecosystems, much remains to be done and explored. In addition to this, in the last few years more people (students, teachers and researchers) around the world are interested in implementing this science to extend the timeline of climate information backwards and understand how climate has changed on scales of decades, centuries or millennia. Therefore, the objective of this work is to describe the general aspects and basic steps needed to conduct a tree-ring climate reconstruction, from site selection and field sampling to laboratory methods and data analysis. In this method's video and manuscript, the general basis in tree-ring climatic reconstructions is explained so newcomers and students can use it as an available guide into this field of research.

Statistical age determination of tree rings.

Dendrochronology, the study of annual rings formed by trees and woody plants, has important applications in research of climate and environmental phenomena of the past. Since its inception in the late 19th century, dendrochronology has not had a way to quantify uncertainty about the years assigned to each ring (dating). There are, however, many woody species and sites where it is difficult or impossible to delimit annual ring boundaries and verify them with crossdating, especially in the lowland tropics. Rather than ignoring dating uncertainty or discarding such samples as useless, we present for the first time a probabilistic approach to assign expected ages with a confidence interval. It is proven that the cumulative age in a tree-ring time series advances by an amount equal to the probability that a putative growth boundary is truly annual. Confidence curves for the tree stem radius as a function of uncertain ages are determined. A sensitivity analysis shows the effect of uncertainty of the probability that a recognizable boundary is annual, as well as of the number of expected missing boundaries. Furthermore, we derive a probabilistic version of the mean sensitivity of a dendrochronological time series, which quantifies a tree's sensitivity to environmental variation over time, as well as probabilistic versions of the autocorrelation and process standard deviation. A computer code in Mathematica is provided, with sample input files, as supporting information. Further research is necessary to analyze frequency patterns of false and missing boundaries for different species and sites.

Potential Food Availability Influences Social Interactions of Young Individuals in a Neotropical Primate (Alouatta palliata).

Deforestation is widely recognised as an agent of human disturbance that causes widespread destruction of species habitats and can result in animals occupying forest patches with limited food resources. When animals are forced to change habitats, they must also adjust their diet, activity budgets and social behaviour in response to facing new ecological and environmental conditions. Only a few studies have analysed the influence of habitat conditions on social interactions of immature howler monkeys. In this study, we examined the effects of variation in food availability on social interactions of young howler monkeys (Alouatta palliata mexicana). This was accomplished by observing infant and juvenile members of two groups inhabiting a continuous forest habitat (640 ha) and three groups living in different-sized forest fragments (4, 42 and 93 ha) for a 15-month non-consecutive period. We quantified the Potential Food Availability Index (PFAI) for each habitat type based on the basal area, the Shannon-Wiener diversity index and abundance of food tree species. We used 15-min focal animal sampling to record the occurrence and/or duration of affiliative and agonistic behaviours. In habitats with higher PFAI, we observed more social play and proximity in infants aged 4-7 months, grooming in infants aged 8-14 months and social play in juveniles. Conversely, juveniles' grooming rates and 0- to 3-month-old infants' proximity rates decreased as PFAI increased. Our results suggest that food resource variation influences young howler monkeys' social interactions. The reduction in social interactions due to low food availability may represent an energy-saving strategy to cope with limited resources in habitats disturbed by anthropogenic activities.