The Biodiversity Campaña Agua de la Sierra is Working to Protect
What is a Sky Island?
Rancho Encinalito and surrounding ranchos sit at the heart of the isolated Sierra de la Laguna mountain range, located in the south extreme of the Baja California Peninsula. This exceptionally rare ecosystem is a hotspot for biodiversity, featuring a wealth of endemic species—meaning they are found nowhere else in the world—that add to its ecological significance. It is a sky island, a mountain with desert or tropical dry forest at its base and pines at its peak, surrounded by a sea of arid habitat that isolates it from other outcrops of similar vegetation.
The Sierra de la Laguna drifted from the Mexican mainland millions of years ago and the elevation gradient, in tropical conditions has allowed for a mixing bowl of species from the Pleistocene and the Tertiary period. The sharp climate gradients along these abrupt mountain slopes lead to the juxtaposition of floral and faunal elements from more than a dozen degrees latitude to the north and south.
Essential riparian corridors.
The Sierra de la Laguna is a lifeline for southern Baja California Sur, sustaining vibrant oases like Todos Santos, Santiago, and Estero de San José. As the state's rainiest region, it receives 650-700 millimeters of rain annually, playing a vital role in regulating the climate for La Paz and Los Cabos. This rainfall replenishes the aquifers that provide water to 67% of the state's population, essential for daily life and economic activities.
Nestled within this landscape, Rancho Encinalito and nearby ranches are located in the crucial Arroyo San Bartolo watershed, a key area for water capture.
This delicate socio-ecological system is under threat. Riparian areas of the Sierra de la Laguna are the oases of life, sustaining a myriad of terrestrial biodiversity. These water-rich zones support complex food webs, from the smallest plants to apex predators, with heightened abundance of reptiles and amphibians in their vicinity. Deforestation and soil erosion from overgrazing have reduced the land's ability to absorb and recharge groundwater. Runoff, high evaporation rates, and climate change, worsened by livestock grazing and water appropriation, pose significant hydrological risks.
A biodiversity hotspot.
As Sierra La Laguna ascends in altitude, the lowland jungle ecosystem gradually transitions into the sole pine and oak forests found in Baja California Sur. These transitional zones, marked by shifts in vegetation, climate, and geography, serve as ideal habitats for a diverse array of flora, fauna, and Mammalia. Along the banks of the ephemeral streams in the Sierra de la Laguna, there used to thrive the Quercus brandegeei, a relict arroyo oak species exclusive to the riparian zones of this mountain range. It is now highly endangered. This unique oak species not only signifies the ecological significance of these riparian habitats but also adds to the rich tapestry of endemic species that call this region home. Quercus brandegeei is one of many species that we hope to restore at Rancho Encinalito with the help of our rancher neighbors in UCAS, who will be propagating seedlings for the project.
Rancho Encinalito recently conducted a comprehensive bioinventory survey, documenting observations across a broad range of species, including plants, fungi, birds, mammals, reptiles, amphibians, insects, arachnids, and diplopoda. The survey highlighted the area's rich biodiversity, with 34 species protected under Mexican law or the IUCN Red List, and 20 species endemic to the region. This underscores the importance of conserving UCAS and Rancho Encinalito’s unique ecosystems.
Find Rancho Encinalito’s full bioinventory here: iNaturalist
Bioinventory observations of note
Mammals
Seventeen mammal species of conservation importance have been recorded throughout Rancho Encinalito.
Birds
One hundred and thirty-five species of birds were identified, ten are cataloged under special protection, two as threatened and two others as endangered.
Herpetofauna
Seventeen species of herpetofauna were identified, nine with some conservation status and seven endemic to Mexico.
Facing a changing climate.
Climate change is already leading to significant impacts in Baja California Sur, including increases in summer daily maximum temperature and decreases in annual precipitation. These effects are expected to worsen in the coming decades, with projections indicating intensified extreme heatwaves and prolonged periods of aridity. These changes are not only reshaping the environment but also posing severe threats to the delicate ecosystems of the Sierra de la Laguna region.
Our work protecting the integrity of arroyos within Rancho Encinalito further underscores the significance of offering havens untouched by erosion and grazing impacts. Together, these habitats epitomize the intricate relationship between climate, topography, and biodiversity, underscoring the imperative for concerted conservation endeavors to safeguard the rich ecological tapestry of Baja California Sur.
