Using Long-Term Research on Middle Spotted Woodpeckers Dendrocoptes medius to Identify Key Unsolved Questions in Ecology and Conservation

Long-term studies provide solid frameworks for addressing key questions in ecology and conservation. First, they allow collecting high amounts of data necessary to assess data-hungry hypotheses. Second, long-term studies allow testing hypotheses that require long time series. Third, they serve as sentinel systems to investigate the effects of sudden environmental changes (e.g., wildfires, floodings, severe droughts). Using the experience on a long-term study (2000-present) of Middle Spotted Woodpeckers Dendrocoptes medius in NW Spain, I identify and propose some approaches for addressing a set of key questions. Long-term studies are essential to investigate lifetime fitness performance of floating adults, which strongly influence population persistence of woodpeckers and many other organisms. A second data-hungry question is related to the factors that influence the use of habitat patches as stepping stones for dispersing juveniles and floaters. Long-term time series are also necessary to investigate population persistence under climate and habitat changes. Moreover, long-term data on woodpecker reproduction and cavity occupancy by secondary cavity users will help understanding the role of woodpeckers as indicators and keystone ecosystem engineers, and will unravel the mechanisms underlying nest-site selection in primary cavity nesters. Finally, woodpeckers´ habitat specialization provides a suitable framework to investigate the drivers of foraging habitat quality in birds. Despite the relevance of long-term woodpecker studies for the generation of robust knowledge, most funding programmes do not promote, or even penalize, studies on these species because they require long periods. This issue biases our knowledge towards model species and systems comparatively easy to study in short periods.