*3.5. How*

This section is how the research in Historical Ecology has been conducted. We differentiated between using Historical Ecology as the main research topic or as an auxiliary topic as detailed in the Methods section. We determined that 37% (44 articles) of the publications had Historical Ecology as the main topic and 63% (74 articles) as auxiliary. We distinguished between practical and theoretical works. Practical studies—using in situ fieldwork methodologies—represent 57% of the works, whereas theoretical—using only ex situ methodologies—are 43% [111,148].

We identified more than 35 different methodological procedures used in the 118 articles. It is worth stressing that many studies comprised more than one method to achieve their objectives. All articles include the traditional literature review, 33 of them conducted interviews [27,95,123,132,133,149], 26 used Geographical Information Systems (GIS) and remote sensing techniques [144,150–155], 26 made floristic and phytosociological analyses, including botanical collections [131,135,142,143,156], 19 collected archaeological materials [74,120,157–160], 16 made soil analysis [80,105,115,161–163], 13 analyzed laws and decrees [124,164,165], 12 made some kind of material dating, including C14 [79,93,158], 11 used free listing [27,166–168], 10 used oral history [117,169], and 10 worked with historical archives consultation [110,113,150], including hemerographic material (newspaper files) [170], and commercial shipping records [136]. With less than 10 works, other methods used were participatory research techniques—including participative cartography and participative archaeology—[84,149,171], travelers' journals consultation [113,147], anthracological analysis (analysis and identification of charcoal based on carbonized wood anatomy) [74,130,143,172], water analysis [155], participative observation [77,121,173], guided tour [127,168], linguistic analysis [117,169], archaeology of the landscape [174,175], photographic sequences analysis [176], discourse analysis [17], among others.
