TY - JOUR
T1 - The Functional Response Ratio (FRR): advancing comparative metrics for predicting the ecological impacts of invasive alien species
AU - Cuthbert, Ross N.
AU - Dickey, James W. E.
AU - Coughlan, Neil E.
AU - Joyce, Patrick W. S.
AU - Dick, Jaimie T. A.
PY - 2019/5/11
Y1 - 2019/5/11
N2 - The Functional Response (FR) has been
identified as a powerful predictive tool to forecast the
ecological impacts of existing, emerging and future
invasive alien species. In particular, the parameters of
attack rate a and handling time h may be predictive of
the ecological impacts of invaders when utilised in
comparison with trophically analogous natives. However, researchers in many cases face somewhat
contradictory impact predictions based on the use of
one parameter or the other. Here, we thus propose a
new metric, the Functional Response Ratio (FRR),
which is simply a divided by h: that is, FRR = a/
h. Given that high values of a and low values of
h should associate with high impact, and vice versa,
the FRR metric balances the information from both
parameters. This also resolves contradictions when
one parameter gives opposite predictions to the other.
Using multiple examples obtained from the literature,
we find that the FRR indeed resolves such contradictions and that values of FRR of invaders are
consistently higher than those of natives, irrespective
of experimental or environmental context. Accordingly, the use of FRR provides a novel and reliable
metric for scientists, stakeholders and practitioners to
predict the ecological impacts of existing, emerging
and future invasive alien species across taxa and
trophic groups.
AB - The Functional Response (FR) has been
identified as a powerful predictive tool to forecast the
ecological impacts of existing, emerging and future
invasive alien species. In particular, the parameters of
attack rate a and handling time h may be predictive of
the ecological impacts of invaders when utilised in
comparison with trophically analogous natives. However, researchers in many cases face somewhat
contradictory impact predictions based on the use of
one parameter or the other. Here, we thus propose a
new metric, the Functional Response Ratio (FRR),
which is simply a divided by h: that is, FRR = a/
h. Given that high values of a and low values of
h should associate with high impact, and vice versa,
the FRR metric balances the information from both
parameters. This also resolves contradictions when
one parameter gives opposite predictions to the other.
Using multiple examples obtained from the literature,
we find that the FRR indeed resolves such contradictions and that values of FRR of invaders are
consistently higher than those of natives, irrespective
of experimental or environmental context. Accordingly, the use of FRR provides a novel and reliable
metric for scientists, stakeholders and practitioners to
predict the ecological impacts of existing, emerging
and future invasive alien species across taxa and
trophic groups.
U2 - 10.1007/s10530-019-02002-z
DO - 10.1007/s10530-019-02002-z
M3 - Article
JO - Biological Invasions
JF - Biological Invasions
SN - 1387-3547
ER -