Environmental policy in collaboration with the University of FloridaEmerging Challenges in Tropical Science Program

ECTS 2: How do natural and human-dominated systems interact?

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Rationale: Superimposed on the climatic and biogeophysical changes that have shaped and continue to shape tropical ecosystems are new driving forces generated by the ongoing transformation of the landscape. At a large scale surrounding our stations is the loss of habitat, increase in edges, and reduction in connectivity that isolates organisms in small and fragmented populations, reduces population genetic diversity, and may cause extinctions.

Changes in ecosystems at fine scale in transformed landscapes, and the feedbacks into the matrix are not yet understood. Examples of these changes are the cascading effects of the loss of top predators that ripple through food webs in the remnant ecosystems, and the concomitant population release of mid-sized herbivores that may overflow into the landscape matrix. Occurring at large scale are matrix-driven impact such as the silent effect of pesticides and other agrochemicals imported through the atmosphere and water that may inhibit some species and promote invasiveness from others.

Conversely, remnant ecosystems may be critical to sustain some large scale processes (and services) such as water and climate regulation, pest control, and vector-borne disease regulation. Along the same line, the balance among different productive and natural systems to ensure sustainable landscape level processes is also a new area that requires research in the tropics. The feedback loops between natural and surrounding human-made systems need to be unraveled in order to manage landscapes more effectively, and maintain an optimal balance of human-made and natural areas that optimizes sustainability and human and environmental health.


Previous work on ECTS 2 at OTS research stations

The complex biological, socioeconomic, and political environment surrounding La Selva Research Station and adjacent private and public protected areas provides a rich field for the study of protected ecosystems within a broader landscape matrix of human uses.

The Central Volcanic Cordillera Conservation Area that surrounds La Selva has been under increasing pressure from a growing agricultural frontier, burgeoning human population, and accompanying major infrastructure (residences and commercial districts, roads, power lines, dams, and more).

These activities have caused increased sedimentation of rivers and streams, increased amounts of pesticides blown into the preserve, noise pollution, and undesirable incursions into the property (e.g., poachers).

Meanwhile, a number of studies conducted at La Selva have documented the changes in land use and their effects on plant and animal communities around the preserved areas, and some effort has been developed to monitor and measure the influx of agrochemicals (mainly pesticides and fungicides) into the La Selva preserve. The need exists to measure these inputs into the natural system and their effects on the ecological integrity of La Selva and the Conservation Area ecosystems, and develop strategies to deal with any deleterious inputs.

Agrochemicals applied in the sugar cane and rice plantations upstream from Palo Verde Research Station and park and water management policies are likely contributing to the cattail invasion that is threatening to eliminate the Palo Verde wetland, an internationally recognized RAMSAR site.

Since Palo Verde National Park is surrounded by an agricultural matrix, it is an ideal location to monitor how changes in agricultural practices, in the context of global climate change, affect not only the Park ecosystem but also human health and other human quality-of-life issues.

Water-use data in the mid and lower Tempisque River Basin, where PVNP is located, is available since the early eighties, providing a unique opportunity to model water balance in the basin and the hydrodynamics of the wetlands. Furthermore, GIS-based models of land use are available for several periods allowing the integration of human effects into the analysis of water use and landscape patterns in the region .

The landscape in which Las Cruces Research Station is located is ideally suited to long-term studies on the effects of habitat fragmentation on populations and communities. Roughly 75% of the forest has been lost over the last 50 years, leaving a mosaic of forest fragments (1-300 ha) immersed in a matrix of coffee farms and pastures.

Existing research has examined the impacts of fragmentation on several groups of fauna establishing a long-term baseline to explore in depth the evolutionary consequences of fragmentation as well as the fine scale exchanges between fragments and their matrix. Other data sets include historic forest surveys as well as data currently being generated by the Forest Dynamics plot at Las Cruces.

Examples of questions for ECTS 2: How do natural and human-dominated systems interact?

These questions are posed for inspiration, but bear no weight on prioritization of proposals. We encourage creativity in the types of questions posed in the proposals.

  • What arrays of reserves within the landscape matrix will sustain biodiversity, ecosystem functions, ecosystem services, and socio-political viability?
  • How do protected areas affect human health and well-being in adjacent communities?
  • What landscape management strategies increase inter-patch connectivity, achieve sustainable populations and communities, and improve their adaptation to climate change?
  • How does nutrient cycling change in protected areas and/or fragmented ecosystems as a result of human activities within the surrounding landscape matrix?
  • How do protected areas, fragmented ecosystems, and areas under human use interact genetically and ecologically?
  • How do mobile toxins such as pesticides, herbicides, and fertilizers impact ecosystem functioning within protected areas? Are natural systems more susceptible to mobile toxins than man-made systems?