By the middle of the nineteenth century, studies suggested that the distribution of the Iberian wolf covered at least 65 percent of the Iberian Peninsula. That share was three times larger than today, according to a team led by the Doñana Biological Station, part of the Spanish National Research Council. To reach these conclusions, researchers examined the geographic dictionary edited by Pascual Madoz in the mid-1800s, which described every city in Spain and its geographic features, alongside statistical models. The work was conducted in collaboration with the German Center for Integrative Biodiversity Research and is published in Animal Conservation.
“Our understanding of declines comes from comparing indices that describe where species lived and how many there were over time”, said Miguel Clavero, a Doñana Biological Station scientist and the study’s lead author. He noted that the data needed to calculate these indices began to be collected relatively recently, even as human impacts had been occurring for centuries.
For this reason, detecting recent drops might only show a small portion of the full picture. What looks like an expansion for some species can be a mirage, the result of focusing on a narrow window of time, much like the wolf today.
For that reason, recent declines could be only a fragment of the overall trend. The observed expansion of some species may simply reflect a limited timeframe rather than true growth, a point echoed in the wolf’s current status.
The current expansion of the wolf
The researcher highlighted that listing the wolf as a specially protected species imposes strong limits on management measures and has met with pushback from some social actors. In this context, he urged an objective assessment of long-term trends and the wolf’s conservation status, beyond what has happened in recent years.
Compared with its historical footprint, today the area occupied by the wolf covers just over 30 percent of the historic range from the mid-1800s. In advocating for a long-term perspective, the idea is that the so-called recent expansion may largely offset the sharp decline the species has endured.
The recovery of the species and its ecological roles point toward a return to historical habitats outside the northwest Spanish region. This long view presents numerous challenges for human coexistence with wolves, especially in places where the species is no longer part of local memory.
The recently published study demonstrates how historical resources can inform current environmental understanding and management. Making productive use of these sources requires careful effort and the application of statistical methods to address knowledge gaps and biases in historical documents.
Stretching the horizon when assessing ecosystem status and the trends of the species that inhabit them can be worthwhile, according to Clavero.
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