Bracken Cave Preserve Established Through One Health Assessment

EcoHealth Alliance
Publié: 07 mars 2022
Dernière modification: 07 mars 2022
remove_red_eye 1594 Vues


The Bracken Cave Preserve is home to the largest bat colony in the world, an estimated 20 million Mexican free-tailed bats (Tadarida brasiliensis). Plans to construct a residential complex along the 1,521-acre tract adjacent to the cave mouth posed a serious risk to wildlife and the potential human population. Motivated by concerns for a nearby aquifer, but limited by a lack of zoning laws in the area, the local government commissioned a report on the potential public health risks of the development. The report outlined concerns for human exposure to various pathogens, from both exploring the cave and the bats’ presence around the new residences. To protect the bat and human populations, advocates from diverse sectors, including conservationists, health experts, city and county governments, and the public water utility, came together to purchase the tract of land. In 2014, the property was officially made into the Bracken Cave Preserve, protecting this area essential for environmental, animal, and human health in perpetuity.


Amérique du Nord
Ampleur de la mise en œuvre
Prairie tropicale, savane, maquis
Écosystémes des prairies
Cadre juridique et politique
Gestion des bassins versants
Gestion des espèces
Gestion et Planification des Aires protégées et conservées
Santé et bien-être humain
Services écosystèmiques
Conservation des espèces et interventions axées sur l’approche « Une seule santé »
Surveillance de la santé de la faune (pour capturer la biodiversité, la santé, les maladies et la surveillance des agents pathogènes)
Surveillance des espèces et recherche
Planification de la conservation des espèces
Évaluation des risques
Gestion des risques urbains et de catastrophes
Territorial and spatial development
Dégradation des terres et des forêts
Perte de biodiversité
Maladies vectorielles et hydriques
Objectifs de développement durable
ODD 15 - Vie terrestre
Objectifs d’Aichi
Objectif 1: Sensibilisation accrue de la biodiversité
Objectif 2: Valeurs de la biodiversité intégrées
Objectif 3: Attraits réformées
Objectif 5: Perte d'habitat réduite de moitié ou diminuée
Objectif 11: Aires protégées et conservées
Objectif 12: Réduction du risque d'extinction
Objectif 14: Services des écosystèmes
Objectif 19: Partage de l'information et de la connaissance


San Antonio, Texas, United States


Before the team purchased the Galo tract to create a preservation, plans were in place to develop 3,500 units and a sprawling residential community. This would have resulted in substantial environmental alterations with cascading impacts on all of the surrounding wildlife, in particular the bat colony and the golden-cheeked warbler population. The human population would be exposed to various health risks through both the bats’ flights and the inevitable human exploration of the Bracken Cave. The development’s potential impact on a nearby aquifer presented additional environmental, social, and health challenges. The area of Texas in which the Galo tract is located has no zoning laws, giving the local jurisdictions no authority to step in and alter the development plans. Without a specific legal mechanism available to stop the residential development, the team determined that only by purchasing the land themselves could they prevent the negative environmental and health impacts of the development.


The health and well-being of surrounding human communities

Mexican free-tailed bat colony

Golden-cheeked warbler population

Surrounding ecosystem

Comment les blocs constitutifs interagissent-ils entre eux dans la solution?

When utilizing a One Health lens to approach any challenge it is essential to work effectively across previously siloed sectors. Human wellbeing is often not considered a part of conservation planning, and the ecosystem services provided by intact natural environments are often overlooked by the human health field. A One Health assessment creates an opportunity to bridge the gap and bring together stakeholders with diverse motivations and a shared goal. The partnership developed to purchase the Galo tract and create the Bracken Cave Preserve was made possible through a report specifically outlining the intersection of the bat colony’s presence and the health and wellbeing of surrounding human communities.


The impact of this solution goes beyond just wildlife conservation and captures the diverse positive effects of a One Health approach in land development planning. The wildlife of the region, including the 20 million bats living in Bracken Cave and the federally endangered golden-cheeked warbler (Setophaga chrysoparia), now live under protection from encroaching human populations. Conservation nonprofits are ecologically managing the region through efforts including controlled burns, ensuring the greater ecosystem’s health. As 3,500 units were prevented from being built along the Galo tract, tens of thousands of potential human residents were protected from the unavoidable exposure to pathogens circulating within the bat population. As demonstrated by the effects of previous spillover events, including SARS, Zika, and COVID-19, the protection to human health provided by the Bracken Cave Preserve is not limited to the individuals who would have lived within the bats’ flight path. Communities as close as next door to potentially as far as the other side of the world have avoided the consequences of a zoonotic disease jumping from the bat population to people.


Traditional environmental impact assessments typically don’t examine risks of zoonotic disease transmission that may result from increased human-wildlife contact created by the development project. The environmental and health impact assessment initiated by the City of San Antonio, in response to a plan to create a residential neighborhood on land adjacent to Bracken Cave, was truly remarkable in that, to my knowledge, it was one of the first instances of a local municipality moving beyond traditional environmental impact assessments by commissioning a study of potential health impacts from zoonotic diseases that would result from the development. Specifically, the city health department wanted to know whether there would be an increased risk of exposure to zoonotic pathogens, such as rabies, as a result of contact with bats or other wildlife that live in and around the cave. Bracken Cave is home to the world’s largest colony of bats. These bats are ecologically and economically important because they consume tons of insects that are agricultural pests. Bats are also reservoirs for rabies virus, which is fatal in people, as well as dogs and cats, when unvaccinated. I appreciated that in addition to the health questions I was brought in to answer, the City of San Antonio was also working with a local bat conservation organization and other environmental organizations to develop a complete understanding of the potential threats to local wildlife. To me, this was a terrific example of One Health science and policy in action. After spending time observing the flight patterns of the bats and interviewing residents from existing communities near the cave, it became clear to me that that there would be substantial opportunities for people and their pets to have contact not only with bats but also other animals like raccoons, skunk and foxes that preyed on the bats at the mouth of the cave and that also carry rabies. The combination of the conservation, environmental and health impact assessments undertaken by the city provided important evidence that the development was problematic.  Bat Conservation International and Conservation International’s ability to raise money and buy the land outright to protect it from development was certainly a win for conservation and public health. To me, the City of San Antonio’s initiative to consider health consequences of increased human-wildlife contact was a win for One Health and a model approach for development globally.

Contribué par

Portrait de salino_41613

Jonathan Epstein EcoHealth Alliance

Autres contributeurs

Ron Nirenberg
City of San Antonio