Background:

The Sonoran Desert toad (Incilius alvarius) is an iconic Sonoran Desert species that has represented rain and fertility in local native cultures for centuries (Villa 2023). The species faces grave threats due to poaching for 5-MeO-DMT, a psychedelic that naturally occurs in the toad’s toxin. Despite 5-MeO-DMT’s Schedule 1 drug status, its popularity has grown substantially due to celebrity endorsements and its reported positive outcomes for treating PTSD and depression. Public misinformation and fabrication of indigenous practices using this toad have compounded these threats, eroding trust in synthetic 5-MeO-DMT alternatives and facilitating collection of wild toads. Rumors that the effects of 5-MeO-DMT can be gained from licking the toads (which is dangerous) recently led the National Park Service to post warnings on social media. Sonoran Desert toads are now believed to be extirpated from their former ranges in New Mexico and California due to poaching for 5-MeO-DMT.

Sonoran Desert toads face other significant threats in addition to illegal collection. Amphibians are considered the most threatened vertebrate class (Luedtke et al 2023), and desert amphibians already exist near the edge of their physiological tolerances.(Zank et al 2014). In Saguaro National Park, these threats are exacerbated by urbanization, habitat degradation, and road mortality.  Rapid urbanization and increasing traffic along the edges of Saguaro National Park are responsible for an estimated average of 29,377 vertebrate deaths annually, with amphibians and small reptiles representing the largest proportions of roadkill (Gerow et al. 2010). Furthermore, the limited water sources within the park that Sonoran Desert toads depend on are directly impacted by climate change and the reduction of available water could pose an even further threat to this species. 

Despite its ecological and cultural importance and myriad of threats, there is a lack of comprehensive data on the Sonoran Desert toad's distribution, population health, and habitat use within Saguaro National Park. This project seeks to address these critical knowledge gaps, enabling informed management actions to ensure the species’ survival and enhance public understanding of its importance. 

Goals of this project:

1: Inventory potential Sonoran Desert Toad breeding sites within Saguaro National Park.

2: Survey the aforementioned potential Sonoran Desert Toad breeding sites during the monsoon breeding season to provide a more comprehensive picture of the distribution of occupied breeding sites within the Park. 

3: Conduct road surveys to document the distribution of road mortalities and identify potential road mortality hotspots that could benefit from mitigation.

4: Work with Saguaro National Park staff and law enforcement to provide educational, public facing, materials about species ecology, cultural significance, and population threats.

5: Produce spatial products recording the spatial coordinates, occupancy status, and physical characteristics of potential Sonoran Desert Toad breeding sites and road kill locations within Saguaro National Park.

Sampling Design and Methods:

We will first work with current and former staff members of Saguaro National Park to identify potential Sonoran Desert Toad breeding sites. These sites may be identified using previous observations or through field surveys to identify low-lying areas, particularly along roads, that may collect standing water during monsoon rains. We will then select a random subsample of these sites using stratification as necessary to ensure that we have geographically even and representative sampling throughout the potential distribution of Sonoran Desert Toads within the Park. We will consult with Park staff to ensure that priority areas are included within our sampling design. During the monsoon season, we will conduct visual encounter surveys at these sites to document the presence and reproduction of Sonoran Desert Toads. We will record counts of all life stages encountered (adults, egg strings, tadpoles, metamorphosed individuals). We plan to deploy acoustic recording units (ARUs) loaned to us by Arizona Game and Fish Department at sites to supplement visual encounter surveys (see Funding Requested). Follow-up surveys will be conducted at confirmed breeding sites as necessary to document the presence of successful reproduction (i.e., the presence of newly metamorphosed individuals). During all surveys we will collect weather data, record information on site physical structure (e.g., road berm pool vs. tinaja, site length and width, presence or amount of submerged and emergent vegetation). To the extent permitted by the data, we will evaluate how site occupancy and reproduction are influenced by site characteristics and the site’s landscape context (e.g., distance from nearest road, surrounding road density). 

During the monsoon season, we will also conduct systematic road surveys to document the distribution and intensity of road mortality. We will work with Park staff to identify priority roads in both Saguaro East and West to include in these surveys. We will record the date and start/end times, locations, and weather conditions during all surveys and will record the spatial coordinates of any live or dead Sonoran Desert Toads encountered. We will create heatmaps of road mortality and overlay those with our breeding site surveys to identify potential hotspots for poaching for 5-MeO-DMT, areas of high road mortality, and breeding wetlands that are of highest value and highest risk for destruction or impairment. 

Expected Outcomes:

The major outcome of this project will include a report summarizing the project’s methods and results and a discussion of those results in the context of providing management recommendations to Saguaro National Park. The report will identify and map potential and confirmed breeding locations, potential travel corridors, and road crossing and road mortality locations and respective potential hotspots. Information on road crossings and mortalities will be used to suggest specific management actions including, but not limited to, road closures, signage, and increased law enforcement presence. A portion of the report not for public release will identify potential high risk areas for poaching that could aid law enforcement operations. Another project outcome will include spatially referenced data files with associated metadata containing the spatial coordinates, site characteristics, and Sonoran Desert Toad breeding activity at potential breeding sites and Sonoran Desert Toad road observations and mortalities throughout Saguaro National Report. Finally, mapping breeding hotspots will provide the opportunity for future population monitoring for population declines and impacts from disease or climate change. These management goals will provide comprehensive protection for the Sonoran Desert toads in Saguaro National Park. An educational and interactive website about the Sonoran Desert toad will be created and made available to the public through the Tucson Herpetological Society and Saguaro National Park. This website will include interpretative posters and an educational video that highlights the importance of the Sonoran Desert Toad and the conservation risks involved with DMT use. These materials will be available for download for private educational purposes by educators, non-profits, and other interested persons. Finally, we will aim to publish a peer reviewed paper based on the data taken in this inventory.

Field Work Design and Goals: 

Summer 2026- Preliminary/ Pilot Year

Goals of the preliminary surveys will include:

• Establish study sites (randomly located field and road transects), focusing near major roadways 

• Assist AZGFD with placement of acoustic recording units (ARUs) within park boundaries 

• Begin coordinating with law enforcement to determine high risk poaching areas

Summer 2027- Primary data collection year

• Full survey protocol, pre- and post- monsoon 

• Identify suitable habitat and breeding sites within the sampling protocol

• Coordinate with law enforcement to patrol sampling areas and high risk poaching areas 

Fall/Winter 2028- Analysis and deliverable year

• Create websites and public-facing materials about Sonoran desert toad ecology and cultural significance

• Compile spatial data into interactive GIS maps with potential breeding sites and create habitat suitability maps 

• Create population models and analyze field data