The Environment Canada Policy Research Seminar Series

Dr. Exequiel Ezcurra April 25, 2002

Dr. Exequiel Ezcurra is known for his expertise on the ecology and conservation of arid zones and management of natural resources in areas under traditional indigenous use. His current research with the Biodiversity Research Center of the Californias aims to protect the environment of the Baja California/Southern California region. Dr. Ezcurra's presentation on April 25, 2003 outlined the unique ecosystem dynamics of this region and some of the contentious sustainable development tradeoffs it presently faces.

Biodiversity of the Region

The Baja Peninsula has a high level of species and ecosystem biodiversity as well as a high number of endemics, species that can only be found in this part of the world. The region's unique set of ecosystems and species results from a confluence of three natural forces: tectonic activity, oceanic currents, and El Niño cycles.

During the Tertiary era, plate movement caused the Baja Peninsula (as it is now known) to collide with the mainland. This collision created the San Andreas Fault and the Sea of Cortés, the narrow body of water that separates the Baja Peninsula from the Mexican mainland. Species that traditionally populated the peninsula during the tertiary period became isolated from the mainland and were able to evolve and adapt to their new surroundings, resulting in the creation of new endemic species. The unique climate of the peninsula aided in this speciation process.

The north-south geographic positioning of the region is significantly influenced by the Pacific Ocean's California Current. As this current moves south towards the equator, it is pushed westward by the equatorial trade winds. The offshore movement of this large body of water causes colder deep oceanic water to rise to the surface, or 'upwelling', in the southern region of the Peninsula. The Sea of Cortés also experiences upwelling caused by strong tidal forces. Both of these upwelling areas provide highly favourable growing conditions for chlorophyll, and thereby bestow a very high level of oceanic productivity for the region. Indeed, these two upwelling areas alone provide 56% of Mexico's total fishery landings.

The California Current is sporadically interrupted by El Niño events (about every 3 to 7 years) or the slowing of the equatorial trade winds. This causes hot water to accumulate along the Pacific coast of the Baja Peninsula, which stops the upwelling process and thus steeply reduces the ocean's productivity. Many coastal species are harmed by the reduced oceanic production that accompanies an El Niño event. For instance, a 20-year analysis of Heerman's gulls, which lay their eggs on a single island in the Sea of Cortés, shows that 90% to 100% of chicks die in El Niño years due to reduced food availability.

On the other hand, in years in which El Niño causes ocean productivity to collapse, higher evaporation rates result in greater rainfall, and the interior deserts teams with life and become highly productive. Over millennia, desert plants and animals have adapted to these sporadic rainfall patterns. Today, El Niño events provide the rainy periods needed for desert species to germinate.

The combination of these three physical forces (tectonic activity, ocean currents, and El Niño cycles) has created high ecosystem and species diversity for such a small region. Indeed, the Baja Peninsula alone has six different ecosystems. Thirteen thousand marine species have been described in the Sea of Cortés region, and it is estimated that over 3,000 more remain undiscovered. Levels of endemism, as measured by the percentage of species found nowhere else in the world, are extremely high - 80% of the region's reptile species are endemic, as are 41% of its mammals, 29% of its birds, and 20% of its plants.

This region has many protected areas, including two large biosphere reserves. Yet many of the endemic species are not adequately protected since they are scattered throughout the Baja Peninsula. Furthermore, the creation of more protected areas would not necessarily provide adequate protection for these highly dispersed species. There is an urgent need for more innovative mechanisms for protection.

Development in the Region

The high productivity and biodiversity of this region has resulted in booming tourism and aquaculture industries. Increases in output of the aquaculture industry, particularly shrimp farming, has caused aquaculture to grow from 9% of total fishery landings to 23%. Growth of these industries has attracted large numbers of people from other areas of Mexico with the population increasing from 4.8 million in 1980 to 7.8 million in 2000, even though birthrates remained around replacement rates. The tourism industry continues to grow at a rate of 10% per year in the Los Cabos area and the population is expected to double over the next 8 years.

The Mexican government's recent Nautical Escalator Project is an ambitious initiative to promote regional tourism and eco-tourism in particular. The project will construct a highway to transport an expected 60,000 boats from the Pacific Coast across the central portion of the Peninsula to the Sea of Cortés, as well as a number of new marinas in the region.

The Mexican government's recent Nautical Escalator Project is an ambitious initiative to promote regional tourism and eco-tourism in particular. The project will construct a highway to transport boats from the Pacific Coast across the central portion of the Peninsula to the Sea of Cortés, as well as a number of new marinas in the region that are expected to harbor some 60,000 boats.

Concerned that such a development might negatively affect the Baja Peninsula and Sea of Cortés region's unprotected biodiversity, The National Institute of Ecology conducted an ecological planning study that included a vulnerability analysis, determining a vulnerability index for component areas in the region based on a pressure index and fragility index. The pressure index was a function of the anticipated population size over a 5-year period, and the associated change in land and resource use. The fragility index was a function of each area's level of biodiversity, number of protected areas, and endemism.

The analysis discovered that the most vulnerable areas were the least populated and more pristine. Correspondingly, it was recommended to the Ministry of Tourism that areas with the highest level of vulnerability be assigned protected area status, while those with the lowest vulnerability see continued use, but with the goal of increasing the sustainability of resource use.

The Nautical Escalator Project, with its goal of increased tourism for local communities, in the setting of the Baja Peninsula, with its large number of unique ecosystems and species, provides an excellent example for understanding the challenge of bridging the need for local, community-based development opportunities with the need to maintain a healthy and vibrant natural environment.