  The recent data from PAMELA and Fermi-LAT can be interpreted as evidence of
new astrophysical sources of high energy positrons. In that case, such
astrophysical positrons constitute an additional background against the
positrons from dark matter annihilation. In this paper, we study the effect of
that background on the prospects for the detection of a positron dark matter
signal in future experiments. In particular, we determine the new regions in
the (mass, $\sigmav$) plane that are detectable by the AMS-02 experiment for
several dark matter scenarios and different propagation models. We find that,
due to the increased background, these regions feature annihilation rates that
are up to a factor or three larger than those obtained for the conventional
background. That is, an astrophysical interpretation of the present data by
PAMELA and Fermi-LAT implies that the detection of positrons from dark matter
annihilation is slightly more challenging than previously believed.
