Long Term Information Powerful for Both Science and Policy

image of intertidal sunset

Long-term ecological information is hard to come by – it requires initial investments of time, energy, and money to get projects off the ground; a dedicated, knowledgeable, and well-trained staff who collect data regularly and accurately; and a sustained funding source to ensure that data collection persists over time.

But long-term data provides powerful insights to trends that are difficult to detect with only a quick snapshot in time, the scale at which many ecological studies occur. Only data collected over multiple years can parse out the difference between natural variability that exists in the system and whether that window of variability is shifting up or down, or getting wider or narrower. For example, on any given day in the summer we may experience a range of highs and lows, but it is hard to tell from one year to the next whether that temperature is within a range we would expect. Observations over time help us construct that range and give us the ability to predict how the environment will affect that range in the future.

New evidence from the labs of PISCO PIs Mark Carr, Pete Raimondi, and Bruce Menge suggests long-term data is more powerful in both science and policy arenas than shorter term studies.

Their recent analysis, conducted by graduate students from both labs, found that Long-term Ecological and Environmental Studies (“LTEES”, defined as studies with durations of at least 4 years) are:

  • more frequently published in important, high impact journals such as Science and Nature, and
  • cited more frequently across the ecological literature than shorter term studies. 

​In addition, LTEES are more frequently cited in National Research Council reports, one of the most influential sources of scientific information pertinent to US policymaking, than in the general literature, suggesting a preference by experts for long-term data. A survey of National Research Council report authors revealed they prefer to use LTEES over shorter term studies when available-- although, the longer term information often does not exist. Long time series, such as data collected by PISCO is not only scientifically important, but also has the potential to contribute to important policy discussions now and in the future. 

“It’s not that short-term research isn’t important,” Menge explains. “Both short- and long-term [studies] are really valuable. A shorter term [experiment] can give you a more mechanistic understanding of long-term patterns. But the longer time series you have, the more power you have to understand changes.”


PISCO, with the help of numerous funders, has filled the role of collecting and providing access to long-term data on rocky intertidal, kelp forest, and nearshore coastal systems for nearly 30 years. For example:

  • In collaboration with our partners at the Multi-agency Rocky Intertidal Network (MARINe) and the National Park System (NPS), PISCO has compiled one of the most extensive rocky intertidal databases in the world, with data from 200 sites spanning from Baja to Alaska collected since 1984. These long-term data sets provide powerful insights for detecting species responses to a changing environment, aiding policy discussions on marine protection, and helping people respond to acute environmental disasters, such as oil spills. These are just a few examples of how PISCO data has contributed to both scientific advancement and society.

  • PISCO fills the role of collecting nearshore oceanographic data not often collected by larger-scale projects. Studies on circulation, productivity, and exposure to OA and hypoxia, for example, help elucidate linkages between oceanic climate changes and ecosystem responses. These data also serve as a baseline for managers interpreting population and community trends, such as those seen in marine protected areas, and can improve our understanding of the geography of OA and hypoxic conditions in the coastal ocean.

  • PISCO has also helped provide data to understand whether marine protected areas (MPAs) are effective off of the coast of California. MPAs are areas that have been closed off to fishing and other extractive activities. PI Jenn Caselle has been involved in monitoring the region surrounding the Channel Islands since 1999. In 2003, the Channel Islands' MPAs were established and she continued to monitor locations inside and outside the MPAs. Analyses after ten years of establishment (2003-2013) showed that most fish within the MPAs are bigger and more abundant, reallocated fishing effort does not impact fish living at the edge of the MPAs, and species heavily targeted by fishing, such as spiny lobster and red abalone, are more abundant within MPAs.

One primary question that PISCO scientists ask is “How do marine organisms and ecosystems respond to environmental change?” As climate change, ocean acidification, and other related phenomena add increasing variability to the global system, long-term data are critical for detecting and monitoring these biological responses. The changing environmental context affects the conclusions scientists can draw from biological data, and provides important reference points for observations. Changes in species or ecosystems are often difficult to detect at short time scales because it can take months, years, or even decades for signals to be identified. In addition, acute changes in the environment, such as a low-oxygen (hypoxic) event, may initiate an acute response from organisms, different from what would be detected in response to environmental change over a longer time frame. Long-term data helps scientists parse out the short-term versus long-term responses important for understanding the overall health of ecosystems.

Check out these resources for more information:

Science of Hypoxia

Sampling Protocols

Studying Sea Star Wasting

Response to the Refugio Oil Spill

Channel Islands' MPAs After 10 years