  Spatial heterogeneity plays an important role in complex ecosystem dynamics,
and therefore is also an important consideration in sustainable resource
management. However, little is known about how spatial effects can influence
management targets derived from a non-spatial harvest model. Here, we extended
the Schaefer model, a conventional non-spatial harvest model that is widely
used in resource management, to a spatially-explicit harvest model by
integrating environmental heterogeneities, as well as species exchange between
patches. By comparing the maximum sustainable yields (MSY), one of the central
management targets in resource management, obtained from the spatially extended
model with that of the conventional model, we examined the effect of spatial
heterogeneity. When spatial heterogeneity exists, we found that the Schaefer
model tends to overestimate the MSY, implying potential for causing
overharvesting. In addition, by assuming a well-mixed population in the
heterogeneous environment, we showed analytically that the Schaefer model
always overestimate the MSY, regardless of the number of patches existing. The
degree of overestimation becomes significant when spatial heterogeneity is
marked. Collectively, these results highlight the importance of integrating the
spatial structure to conduct sustainable resource management.
