This paper advances new methods for ecosystemic approaches to evolutionary music and art. We explore the biological concept of the niche and its role in evolutionary dynamics, applying it to creative computational systems. Using the process of niche construction organisms are able to change and adapt their environment, and potentially that of other species. Constructed niches may become heritable environments for offspring, paralleling the way genes are passed from parent to child. In a creative ecosystem, niche construction can be used by agents to increase the diversity and heterogeneity of their output. We illustrate the usefulness of this technique by applying niche construction to line drawing and music composition.