Understanding habitat threats will help oak dependent and oak associated birds
Oak and prairie habitats look very different across the Pacific Northwest, but they all face similar threats. That’s the conclusion that emerges from strategic action planning processes undertaken by local partnerships working on oak and prairie habitats from southern Washington to northern California.
There are five oak and prairie partnerships that are currently developing strategic action plans and they are all taking a systematic approach to understanding the highest priority local threats. Open Standards is an adaptive planning framework used by a host of conservation organizations around the world. Its software companion, Miradi, rates threats based on scope, severity, and irreversibility. The East Cascades Oak Partnership, the Intertwine Oak and Prairie Working Group, the Willamette Valley Oak and Prairie Cooperative, the Umpqua Oaks Partnership, and the Klamath-Siskiyou Oak Network are all using Open Standards in their planning efforts. Each partnership rated threats to oak and prairie systems in their regions that collectively span the primary range of Oregon white oak dominated systems.
Each partnership is unique, with differences in land use, the mix of stakeholders, growth projections, species composition, and public policies. However, when all of the partnerships are considered in sum, it is clear that there are more similarities than differences in the major threats to oak and prairie habitats, and the threats are landscape-wide.
There is no single, fail-proof strategy that will reverse habitat loss. To be the most effective, strategies often need to be implemented at both the local and regional levels. The threat commonalities that the Open Standards process brought to light suggest there is great potential to address them with increased collaboration at the regional scale.
Here are the priority threats that were common across the region.
FIRE EXCLUSION Fire is a natural and beneficial part of the oak and prairie ecosystem. In the last 100 years, fire has been excluded from these systems due to extreme suppression and the end of burning by Native Americans. This has led to oak stands that are overloaded with fuel and dominated by less fire-tolerant and more shade-tolerant plants. These plants are often non-native and decrease recruitment of oaks and overtake native understories.
URBAN AND RURAL RESIDENTIAL DEVELOPMENT The range of Oregon white oak is coupled with people. Small-acreage homesites are increasing in value and demand, and urban growth boundaries are expanding. Projections show that growth will radiate south and east out of the Portland Metro region into the interior valleys of Oregon.
CONVERSION TO AGRICULTURE The majority of oak and prairie habitat today is located on privately-owned lands. Conversion of these remnant habitats to intensive agriculture includes vineyards, orchards, hemp, and other croplands.
INCOMPATIBLE GRAZING Grazing can be compatible with oak and prairie conservation, but it is difficult to manage effectively for a diverse understory of native plants.
INVASIVE, NON-NATIVE SPECIES Invasive non-native species in oak and prairie systems are pervasive. The loss of native taxa and replacement by invasives (forbs, grasses, and woody plants) has resulted in severe declines in many oak-dependent species.
CONIFER ENCROACHMENT Mostly attributed to fire exclusion, conifer encroachment continues to be a major threat to oak systems across the range of Oregon white oak. Needlecast and shading from conifers alters the understory of oak systems. As conifers mature, they will crowd out and overtop oaks, resulting in decreased growth and eventually oak death.
CONVERSION TO COMMERCIAL TIMBER The Pacific Northwest is known for its timber production. Oregon is the top producer of softwood, representing 16% of total production in the U.S. As timber product needs increase, new areas are being converted to commercial timber lands, and oak forests in private ownership are a target.
Sara Evans-Peters, Conservation Specialist with Pacific Birds, submitted this post.