UADY Tree Diversity Experiment (Mexico)


The UADY Tree Diversity Experiment was established in Yucatan, at a site owned by INIFAP (Mexican Institute for Forestry and Agriculture), in December 2011. To test for species richness effects, two types of plots were planted: monocultures and four-species mixtures. For big-leaf mahogany (Swietenia macrophylla), one of the component species, we also manipulated the number of genotypes (maternal lines) to test for effects of genotypic diversity within this species. Tree growth, functional traits, and bi- and tri-trophic interactions between trees, herbivorous arthropods, and natural enemies of these herbivores are being studied.

aerial photo UADY
Aerial view of the experimental site, surrounded by a matrix of secondary tropical forest


Design
The experiment consists of 74 plots of 21 m x 21 m. Monocultures (two plots per species, except for mahogany) and four-species mixtures were planted. Mahogany was planted in 59 of the 74 plots: 12 mahogany monocultures of a single maternal line or genotype (2 plots/genotype), 20 mahogany monocultures containing four mahogany genotypes, 12 four-species plots in which all mahogany saplings were of one genotype (two plots/genotype), and 15 four-species plots within which four mahogany genotypes were planted. Thus, mahogany genotypic diversity is fully crossed with tree species diversity.

The species and genotype richness treatments contain equal numbers of individuals of four species or four mahogany genotypes. In addition, all the non-mahogany species are equally represented across the four-species mixtures, with each species present in six plots. Similarly, each mahogany genotype is represented in a similar number of the four-genotype mahogany monoculture plots (8 or 9 plots per genotype). Besides, each genotype is also present in a similar number of four-species mixtures in which the four genotypes were planted together (9 or 10 plots per genotype). The plots of each diversity treatment combination were randomly distributed throughout the experimental site.

Seeds of all species were collected from adult plants in southern Quintana Roo (México) between January and March 2011. The distance among the source trees ranged from 1.5 to 50 km. Seedlings were four months old when planted.

design UADY
Layout of the plots at the site, with 6 m wide corridors between them


Site characteristics

location Muna
former land use orchard, pasture
altitude 20 m
soil type calcic cambisols and luvisols
area 7.2 ha
no of plots 74
plot size 441 m2
no of trees planted 4780
planting date 2011
diversity variables species richness
genotype richness
diversity gradient 1, 4 sp.
1, 4 genotypes (mahogany)
size species pool 6 species
6 genotypes
species pool Ceiba pentandra, Cordia dodecandra, Enterolobium cyclocarpum, Piscidia piscipula, Swietenia macrophylla, Tabebuia rosea
contact persons Luis Abdala-Roberts
Víctor Parra-Tabla



Research

The effects of tree species diversity and mahogany genotypic diversity on herbivory and parasitism associated with these herbivores are monitored from the start of the experiment. Much of this work has been centred on insect herbivores feeding on mahogany (e.g., leafhoppers, stem borers, and leaf miners) for which both diversity effects can be evaluated. In addition, diversity effects on plant functional traits (e.g., architecture, anti-herbivore defences), tree growth, and bi- and tri-trophic interactions between plants, herbivorous arthropods, and natural enemies (other arthropods and birds) of these herbivores are also investigated.



Extra information

For more information on the UADY Tree Diversity Experiment, send an e-mail to the contact person, or explore the publications:

  • Esquivel-Gómez L, Abdala-Roberts L, Pinkus-Rend&oacture;n, Parra-Tabla V (2017) Effects of tree species diversity on a community of weaver spiders in a tropical forest plantation. Biotropica 49: 63-70 - doi: 10.1111/btp.12352
  • Abdala-Roberts L, González-Moreno A, Mooney KA, Moreira X, González-Hernández A, Parra-Tabla V (2016) Effects of tree species and genotypic diversity on leafminer-parasitoid interactions. Agricultural and Forest Entomology 18: 43-51 - doi: 10.1111/afe.12125
  • Abdala-Roberts L, Mooney KA, Quijano-Medina T, Campos-Navarrete MJ, González-Moreno A, Parra-Tabla V (2015) Comparison of tree genotypic diversity and species diversity effects on different guilds of insect herbivores. Oikos 124: 1527-1535 - doi: 10.1111/oik.02033
  • Campos-Navarrete MJ, Abdala-Roberts L, Munguía-Rosas MA, Parra-Tabla V (2015) Are tree species diversity and genotypic diversity effects on insect herbivores mediated by ants? PLoS ONE 10 (8): e0132671 - doi: 10.1371/journal.pone.0132671
  • Campos-Navarrete MJ, Munguía-Rosas M, Abdala-Roberts L, Quinto-Cänovas J, Parra-Tabla V (2015) Effects of tree genotypic and species diversity on the arthropod community associated with big-leaf mahogany. Biotropica 47:579-587 - doi: 10.1111/btp.12250
  • Abdala-Roberts L, Moreira X, Cervera JC, Parra-Tabla V (2014) Light availability influences growth-defense trade-offs in big-leaf mahogany (Swietenia macrophylla) King. Biotropica 46: 591-597 - doi: 10.1111/btp.12133
  • Moreira X, Abdala-Roberts L, Parra-Tabla V, Mooney KA (2014) Positive effects of plant genotypic and species diversity on anti-herbivore defenses in a tropical tree species. PLoS ONE 9(8): e105438 - doi: 10.1371/journal.pone.0105438


photo mixture, corridor, monoculture photo monoculture
A corridor between a mixture and monoculture, and a mahogany (Swietenia macrophylla) monoculture 1.5 years after the start of the experiment (June, July 2013)


photo monoculture photo mixture
A monoculture (Enterolobium cyclocarpum) and a mixture 3.5 years after the start of the experiment, with the trees 6 to 12 m tall, depending on the species (August 2015)