The growing field of urban political ecology (UPE) has greatly advanced understandings of the socio-eco- logical transformations through which urban economies and environments are produced. However, this field has thus far failed to fully consider subjective (and subject-forming) dimensions of urban environ- mental struggle. I argue that this can be overcome through bringing urban political ecology into conver- sation with both post-structural political ecology and critical geopolitics. Bridging these literatures focuses attention on practices of socio-ecological exclusion and attachment through which environmen- tal subjectivities are formed. This argument is drawn out through a case study of the politics of local eco- nomic development and conservation within the watershed of the Big Darby Creek near Columbus, Ohio. This struggle was driven by a preservationist movement that coalesced around a shared understanding of socio-ecological hybridity as a source of metaphysical insecurity. Hybridity appears here as a site of polit- ical and ethical struggle over social and ecological exclusions produced in the pursuit of security. This case study demonstrates a paradox of environmental politics: the non-human is at once a site of constit- uent possibilities for identity and subjectivity as well as forces which seek to foreclose this radical open- ness. Recognizing the paradoxical nature of environmental struggle allows for a more complex and nuanced account of the multifarious forces that shape the formation of environmental subjectivities.