Seeing the Forest and the Trees

In the megadiverse lands of southwestern Ecuador and northern Peru, the tropical dry forest of the Tumbesian region ranks as one of the world’s highest biodiversity priorities. Rich in flora, the area hosts many endemic and endangered species.

Broad and beautiful trees, locally known as ceibas Ceiba trichistandra, grace this forest. The trees boast buttress roots skirting out from the tall trunks 9-12 feet from the ground. Their branchless green trunks culminate in huge extended canopies reaching out in a complicated lattice, embellishing the forest and contrasting with the intense blue sky.

Unfortunately, only 5% of the forest’s original distribution remains, with the rest having been converted or cleared in the last century. The remaining forests continue to be threatened by overgrazing by livestock, land clearing for agriculture, and logging. 

Fortunately, our partner, Nature and Culture International (NCI), through its mission of conservation through Latin America, has purchased very important pieces of these forests, supported local communities in the creation of communal reserves and worked with municipal, regional, and national governments to establish more reserves.

To support these efforts, scientists with the Institute for Conservation Research initiated a collaborative research effort to better understand the ecology of this important ecosystem and how it can be managed and support the needs of local communities, which rely on resources from the forest for their livelihoods.

In 2011, we began evaluating the health of the forest and the effects of livestock grazing on forest composition. Specifically, we are measuring the diversity of tree species and the damage done to their bark or branches by livestock. The study extends across the landscape, encompassing the various vegetation habitats of the lowlands, the highlands, and in between.

Additionally, we have established an experiment by fencing some areas to exclude livestock. With this experimental design, we will be able to see the differences between grazed and nongrazed areas. We expect to find higher regeneration and diversity in fenced areas. Preliminary results clearly show an increase in vegetation cover, a higher number of tree recruits, and less mortality of seedlings and saplings in fenced areas. The experiment results will help us know what to expect when grazing pressure declines.

The goal is to help manage livestock—not completely eliminate their presence—on the landscape. Keeping people from raising livestock is not feasible, as many people in the area rely on livestock as their only source of income. One option for reserve management is to work with local people to designate the long-term use of different areas within the reserve, with zones earmarked for grazing.

Our work on grazing will help determine which areas may better support grazing and at what intensity and which should be left for conservation. In helping to inform and improve livestock management, we hope to contribute to the conservation of the incredible biodiversity of the Tumbesian forests.

Bryan Endress, Ph.D., Director of Applied Plant Ecology, San Diego Zoo Global Institute for Conservation Research.