Reforestation
With direction from Dr. Jorge Carlos Berny Mier and Teran
We have been doing reforestation activities in two areas: a previously planted area, filling where trees died off, and new areas surrounding the main building. We included various tree species: canistel (Pouteria campechana), cedro (Cedrela odorata), ceiba (Ceiba petandra), ciricote (Cordia dodecandra), mahogany (Swietenia macrophyla), palma real (Roystonea regia), ramon (Brosimum alicastrum), wild avocado (Persea americana), zapote (Manilkara zapota). All of these tree species are important for forest diversity and for faunal nutrient sources. The plants have been initially irrigated and followed up with general maintenance.
Effect of Bird Migration on Insect Populations in Disturbed and Old
Growth Forests
Each year, over 4 billion birds migrate south from the United States to México. Those that make the journey across the gulf of México from Texas to Yucatán are unable to stop for food during their journey and arrive eager to feed. The aim of this project is to estimate how insect populations respond to the influx of migratory birds in younger, less diverse forest and older, more diverse forest. We will study this using novel autonomous insect sensors verified by sticky traps, audio recordings of bird songs, and surveys of traditional ecological knowledge.
Through a collaboration with Dr. Emily Bick (postdoctoral fellow at the University of Copenhagen) and Kimberly Gibson (PhD Student at the University of California, Davis), five FaunaPhotonics insect sensors were installed at Reserva San Nicolás in September 2021. Three sensors were installed in younger, less diverse forest and two were installed in older, more diverse forest. The sensors operate by sending out a beam of light which flying insects can pass through. When an insect flies though the beam, light is reflected back to the sensor and is translated into about 30 different metrics including wing beat frequency, body-size to wing-size ration, flight direction, color, speed, and size. With a training dataset, the sensor data can be used to identify the insects´ species, age, sex, and mating status. With an untrained model, insect groups including bees, parasitoids, predatory wasps, moths or butterflies, and general insect biodiversity are identifiable from these features.
We hypothesize that the rate of insect flights will decrease in response to bird migration, due to birds predating insects. Moreover, we hypothesize that the rate of flights recorded, and the category of flying insects will respond differently to the multiple waves of bird migration.
Through a collaboration with Dr. Felipe Campos Cerda of Universidad Nacional Autónoma de México, we are collecting audio recordings of migratory birds in each study location at Reserva San Nicolás.
These recording are being taken with an Audiomoth recorder and will be analyzed using machine learning to confirm the presence of various migratory bird species at the reserve. We will compare the findings of these recordings to oral survey data collected from indigenous elders in neighboring communities about the arrival and departure time, preferred habitat, and feeding behavior of various migratory birds. The traditional ecological knowledge of these elders, along with other existing datasets, will help us link the bird and insect data collected in this project. From this work we hope to better understand how habitat destruction and conservation affect the ecosystem services that birds and insects provide to the local community.
Herbivores are key drivers of plant population dynamics and species diversity, and have especially strong effects in biodiverse tropical forests. Two important factors determining herbivory are host plant density (number of seedlings per unit of area) and relative frequency (how common one species is relative to other species). Theory predicts that herbivory should increase with both density and frequency of host plants. Unfortunately, studies have overwhelmingly addressed density effects without controlling for frequency, thus limiting our understanding of the relative contributions of these factors. To address this gap, we recently established an experiment with seedlings of four tree species, namely Cordia dodecandra, Brosimum alicastrum, Manilkara zapota, and Piscidia piscipula. The first three are rare but represent a highly important food source for local fauna and some are timber species, whereas the latter is a highly common species in tropical forests of the Yucatán Peninsula. The experiment consists of 1 by 1 m plots planted in the forest understory at the San Nicolás Reserve, for which we jointly manipulated seedling density for the first three (focal) species as well as their frequency relative to P. piscipula. The experiment started in August 2021 and we are currently conducting surveys measuring seedling growth and insect herbivory. Following theory, we expect that both seedling density and frequency will positively correlate with herbivory. The predicted frequency effect implies that common tree species such as P. piscipula drive decreased herbivory on rare species and thus promote their recruitment as long as the tree species are attacked by different insects. Overall, this study aims to improve our understanding of the dynamic interplay between seedling density and species frequency effects on plant-herbivore interactions and tropical forest regeneration.
Tree species seedling density and frequency effects on insect herbivory and forest regeneration an experiment with Dr. Luis Abdala Roberts and Dr. Jorge Berny-Mier y Terán