Dr. Cuauhtémoc Sáenz-Romero, his colleagues, and graduate students continue working on their assisted migration experiments. Preliminary results of four field sites at Nevado de Toluca, State of México indicate that after a year of having been planted, oyamels (Abies religiosa) have an overall survival rate of 80.6 % (August 2022). Mortality increases significantly if the shift upwards exceeds 600 m of altitudinal difference between the seed source and the planting sites.
This research and the challenges faced by the conservation and survival of oyamels in the overwintering sites of the monarch and its assisted migration has received international recognition! Some of the recent articles on popular media published on this topic can be found on USA Today, Reader’s Digest, and National Geographic.
To improve the survival of the oyamel (Abies religiosa) in future reforestations, Dr. Saénz's team also conducted experiments on the propagation of Coyote brush (Baccharis conferta) and Snakeroot (Ageratina glabrata) nurse plants in nurseries. Using shrubs as nurse plants, provides protection to young oyamel seedlings from excessive heat and extreme temperatures.
An experimental reforestation was carried out planting these two
species of shrubs at 3400 m altitude at Cerro Prieto Ejido in Sierra
Chincua to try to cover a site that was highly disturbed by the winter
storm of March 2016 with shrubs. Once established, the shrub cover will
serve as a nurse plants for subsequent reforestation with oyamel in
the future. Survival after eight months of planting was 78% in Baccharis conferta and 65% for Ageratina glabrata.
These results are considered encouraging, especially considering that
these shrubs had never been planted in nurseries before or used for
reforestation since traditionally they have been considered marginal. A
video of the process is shown below.
Another experimental site was set up at El Rosario where oyamels are being planted at three altitudes (3335, 3240, 3230)
with nurse plants(Bacharis conferta – coyote brush and Eupatorium
labratum– snakeroot) to see how well oyamel trees survive under
the shade provided by the nurse plants at the different altitudes.
The experiment was set up at the beginning of July, 2022 and we will
have to wait and see how long it takes the nurse plants to grow enough to
provide enough shade for the oyamels at the different altitudes.
Publications in Scientific Journals
The Monarch Butterfly Fund has supported this important research for several years and many papers have been published in scientific journals. The following links give access to some of the most relevant ones:
- Pinus pseudostrobus
assisted migration trial with rain exclusion: maintaining Monarch
Butterfly Biosphere Reserve forest cover in an environment affected by
- Reciprocal Common Garden Altitudinal Transplants Reveal Potential Negative Impacts of Climate Change on Abies religiosa Populations in the Monarch Butterfly Biosphere Reserve Overwintering Sites
- Ecological Restoration of Abies religiosa Forests Using Nurse Plants and Assisted Migration in the Monarch Butterfly Biosphere Reserve, Mexico
- Genetic Variation in Abies religiosa for Quantitative Traits and Delineation of Elevational and Climatic Zoning for Maintaining Monarch Butterfly Overwintering Sites in Mexico, considering Climatic Change
- Drought years promote bark beetle outbreaks in Mexican forests of Abies religiosa and Pinus pseudostrobus
- Drought occurrence and forest management: Interrelated drivers of sanitary logging in central México temperate forests