Analysis of spatial and temporal patterns of diversity and abundance in ecological data has been an important focus in ecology. Nevertheless, ecological data such as multi-species data sets are often difficult to analyze because species are usually unevenly represented and multiple environmental covariates may describe their distributions. Although typical univariate, bivariate, and multivariate statistics provide rigorous tests of hypotheses, they have limited capacity to quickly identify relationships among multiple species and environmental covariates, or detect change over time. We propose a novel visualization technique, the Diversity Map, which facilitates the visual inspection of the distribution, abundance, and covariates of large multi-species data sets using an interactive web-based visual interface. To develop this tool, we have taken a user-centered design approach, in which our team of ecologists, information managers, and computer scientists collaborate closely during the development process. Initial findings indicate that this tool is extremely valuable for ecologists in the early stages of data exploration, prior to further statistical analysis. In this paper, we discuss our design approach, the design elements, and implementation of the Diversity Map tool and we demonstrate how the tool can help scientists gain insights into spatial and temporal patterns of ecological data. The use of this tool is illustrated with data on moth diversity and abundance from the HJ Andrews Experimental Forest.