species-paper.sty

\usepackage{csquotes}

\theoremstyle{definition}
\newmdtheoremenv{definition}{Definition}

\emergencystretch=1em

\newcommand*\titleheader[1]{\gdef\@titleheader{#1}}
\AtBeginDocument{%
  \let\st@red@title\@title
  \def\@title{%
    \bgroup\normalfont\large\centering\@titleheader\par\egroup
    \vskip1.5em\st@red@title}
}