"Científico" is a classic false friend. It does not mean always mean scientific, and "scientist" or "scientific" are wrong here. Most of the research staff at CSIC are scientists, but by no means all them are. I translate regularly for several of those that aren't: historians, particularly. The first of its eight subject areas is Humanities and Social Sciences. There are many web pages relating to the CSIC and its staff that use the words "scientist" or "scientific", but these are just crude literal translations of the Spanish. "Científico" really means academic or research-related. An "artículo científico" is an academic article or research article; it can be on literature or history, or example, and by no stretch could you call that a scientific article.

Indeed, the very name of CSIC, Consejo Superior de Investigaciones Científicas, illustrates this. A significant minority of its institutes are not scientific at all. It should be translated as something like the Spanish National Research Council (which is what it calls itself in the English version of its website).

Well, "escalas científicas" refers to people who have permanent (tenured) posts at CSIC, in one of the three permanent grades: científico titular, investigador científico and profesor de investigación (from lower to higher: the last means research professor and is equivalent to a university catedrático). There are other staff at CSIC who do not have permanent tenured positions — contract staff and post-docs, particularly — but "escala científica" refers to those that do.

See slide 25 here:
https://www.slideshare.net/ctorranog/investigacin-en-el-csic

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Note added at 11 hrs (2019-02-23 21:52:27 GMT)
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I should make it clear that "permanent research staff" is a translation of the whole phrase "personal de las escalas científicas".