Introduction

FLORISTIC INVENTORY OF SELECTED SITES IN THE NULATO HILLS, WESTERN ALASKA 1997-1998 Carolyn Parker, Research Assistant University of Alaska Museum Herbarium, Fairbanks (ALA) Introduction

Bureau of Land Management (BLM) recognizes its legal responsibility to prevent rare plant and animal species from becoming threatened or endangered with extinction in the areas under their management. An important aspect of this responsibility is to support inventories in these areas for rare species, determine the localities and habitats in which rare species are likely to occur, and to document known occurrences with permanently curated collections. Sound management decisions that may affect rare taxa can only be made when this information is available to land managers.

The Nulato Hills of central western Alaska (Figure 1) were almost botanically unknown prior to this survey. The few existing plant collections from the region were taken from along the Bering Sea coast and the Yukon River bordering the Hills to the east (ALA-Northern Plant Documentation Center, Hult»n 1940) and these collections represent primarily coastal and interior lowland habitats. Canadian botanists A.E. and R. Porsild visited the lowest foothills east of Unalakleet briefly in 1926 and made a few collections now held at the National Museum of Canada (CAN) in Ottawa (Porsild 1939). The northwestern margin of the Nulato Hills is included in two soil and vegetation surveys relating to reindeer range management (Swanson et al. 1985, Van Patten 1990). A river management plan for the Unalakleet River, most of which is designated as a part of the National Wild and Scenic River System, has been published (BLM 1983). A land cover database has been created by BLM primarily using remote sensing techniques which define vegetation cover classes using only a few of the most common and abundant plant species (Meyer and Spencer 1983). There is no record that the upland and alpine areas, which are very remote, have ever been visited by botanists.

This area has the potential to be botanically interesting. Recent floristic surveys sponsored by National Park Service (NPS) on the Seward Peninsula have shown that area to be rich in species narrowly endemic to the Bering Straits region as well as species with a predominantly Asian distribution that barely reach North America (Kelso 1983). Many of these species are rare in Alaska, including some plants categorized as 'species of concern' by the U.S. Fish and Wildlife Service (USFWS) or rare to critically imperiled by the Alaska Natural Heritage Program (AKNHP). In addition, two new species have recently been described from the area (Kelso 1987, Kelso et al. 1994).

The Nulato Hills extend northward toward, and are nearly contiguous with, uplands of the eastern Seward Peninsula. It seems reasonable to suspect that these adjacent subalpine and alpine landscapes, which support the majority of rare plant species in the Seward Peninsula, may act as a 'stepping stone' corridor for migration and hence, some of the same species may be also found in the Nulato Hills. In addition, a similar corridor of uplands exists northward to the Brooks Range, connecting the Nulato Hills with the arctic circumpolar flora of northern Alaska. These upland migration routes could potentially have enriched the Nulato Hills with plant species from the distant, endemic-rich arctic region. In contrast, the southern portion of the Nulato Hills extends toward the Yukon-Kuskokwim delta and lowlands, and stands relatively isolated from the Kuskokwim Mountains to the southeast.