Chart and table of population level and growth rate for the Merida, Mexico metro area from 1950 to 2025.

The environmental variability at local scale results in different physiognomic types of mangrove forest. However, this variability has never been considered in studies of mangrove genetic variability. This study analyzed the genetic and morphological variability and structure of Rhizophora mangle at regional and local scales in the Yucatan Peninsula. Thirteen mangrove populations (eight scrub and five tall), located in seven sites, were sampled, and their morphological variability and relationship with the availability of phosphorus and salinity were analyzed. The diversity and genetic structure were estimated at different hierarchical levels with nine microsatellites, also Bayesian inference and Principal Coordinates Analysis were used. We found a great morphological variability of R. mangle that responded to local environmental variability and not to the precipitation gradient of the peninsula. The genetic diversity found in the peninsula was greater than that reported for other populations in Mexico and was grouped into two regions: the Gulf of Mexico and the Caribbean Sea. At a local scale, tall and scrub mangroves had significant genetic differentiation suggesting that ecological barriers promote genetic differentiation within sites. These results need to be considered in future population genetic studies and for mangrove management and conservation.

This project is based on cross-sectional studies of Merida and vicinity residents, Yucatán, Mexico. In 1994, 364 men and 320 women aged 20-98 years were measured. Most of them were purely Mayas. The analysis included 3 phenomena: secular trend in height, sexual dimorphism index in height which assess living conditions, and age at menarche in women. From the literature, it is known about the living conditions of Maya men and women at the turn of the 19th and 20th centuries. Haciendas producing henequen were based on the work of men and despite very bad living conditions, the owners took care of their health. Women were treated very badly. After the Mexican revolution, the whole industry related to production of henequen collapsed. Mayan living conditions improved a little, but at the end of the 20th century the biological status of men did not change, but improved somewhat in women. This is the reason why Maya women gain greater height, despite the lack of acceleration in maturation.