Using an experimental approach, we investigate income distribution among heterogeneous subjects exploiting a Common Pool Resource (CPR). The CPR experiments are conducted in continuous time and under different treatments, including combinations of communication and monitoring. While many studies have focused on how real-life income inequality affects cooperation and resource use among groups, here we examine the relationship between individuals’ cooperative traits, harvest inequalities, and institutional arrangements. We found that: (1) When combined with monitoring, communication decreases harvest inequality—that is, harvest is more equally distributed among individuals in all treatments; and (2) the cooperative trait of individuals significantly predicts harvest inequality. The relative proportion of non-cooperators and cooperators (i.e., the cooperative dependency ratio) drives the within-session harvest distribution—as the cooperative dependency ration increases, the income distribution becomes increasingly unequal, leading to a downward spiral of resource overexploitation and scarcity. Finally, our results suggest that harvest and income inequalities are contingent to resource abundance, because under this regime, non-cooperators exert the greatest amount effort—thus leading to resource scarcity and income inequalities.