A natural resource condition assessment for Sequoia and Kings Canyon National Parks: Appendix 12 – intact forests.

Battles, John; Saah, David; Robards, Timothy; Cousins, Stella; York, Robert; Larson, Debra

Sequoia-Kings Canyon National Parks (SEKI) encompass striking physical gradients that include more than 4,000 m of relief and the rain shadow effect of the Great Western Divide (Stephenson 1998, Urban et al. 2000). As a result, the landscape ranges from barren peaks to massive conifer forests to dry shrublands. Despite this diversity, forests are the most common vegetation type. In SEKI, they account for ⅓ of the area and almost ½ of the non-barren lands (USGS-NPS Vegetation Mapping Program 2007). For this Natural Resource Condition Assessment (NRCA), we have divided the SEKI forests into two focal resource categories: Foothill Vegetation and Intact Forests. Foothill vegetation includes the oak-dominated forests that occur largely below 1,830 m elevation (Rodriguez-Buritica and Suding, NRCA assessment). Intact forests consist of the expansive conifer-dominated ecosystems that occur in the montane habitats of SEKI. These forests, along with their angiosperm affiliates, cover 97,746 ha and account for 84% of the area classified as forest (USGS-NPS 2007, Map 1). For this analysis, a forest is defined as a vegetated landscape with trees over 5 m tall, with their crowns interlocking, and generally forming 60-100% cover (NatureServe 2004). Intact refers to forests that have not been harvested or otherwise developed since European settlement. The critical question for intact forests at SEKI is how ―intact are they? The concept of ecological integrity has proven to be a useful framework to assess the condition of protected ecosystems (Parrish et al. 2003, Tierney et al. 2009, Reza and Abdullah 2011). In broad terms, ecological integrity can be defined as the capability of the ecosystem to maintain the composition and structure of the biological community; the productive capacity of the ecosystem; and the ability to recover from stress and disturbance. Given this definition, it is clear that integrity shares an intellectual history with ideas expressed in terms of ecosystem health, ecological sustainability, and resilience (Rapport et al. 1998). The distinguishing feature of integrity is its explicit focus on informing management decisions and evaluating conservation efforts. Recently Tierney et al. (2009) evaluated the structure, composition, and function of forests in the National Parks of the northeastern United States in terms of ecological integrity. Their work provides a template for the condition assessment of the SEKI forests. Thus our critical questions focus on addressing the key components of integrity as identified in Tierney et al. (2009): Does the landscape structure in terms of patch size and continuity support species that rely on habitats found in the interior of forests? Do the intact forests recruit a sufficient abundance of large-diameter trees (live and dead) that are essential to maintaining structural complexity and habitat heterogeneity? Are the intact forests self-sustaining and productive?

A natural resource condition assessment for Sequoia and Kings Canyon National Parks: Appendix 12 – intact forests.

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