Presentation on theme: "Key Features of Early Seral Habitats for Wildlife"— Presentation transcript:
1Key Features of Early Seral Habitats for Wildlife Matt LeeJoan HagarUSGS-FRESC
2Matt Lee Matt Lee Matt Lee All of these species rely on food resources from a large diversity of non-coniferous plants in early seral stagesMay use seedling and sapling conifers for cover or food, but that is probably not the main resource that attracts these species to early seral habitats
3Following Natural Disturbance ... Bob AltmanFollowing Natural Disturbance ...StructureLegacy trees and snagsOpen (low tree density)Large woodCompositionHerbs and GrassesShrubsDeciduous hardwoodsWhy do early, shrub-dominated stages of forest succession typically support high animal diversity than other stages?Elements/legacies of old-forest remain; combined with flush of productivity from newly available resources (light)2 important influences on wildlife
4IF appropriate habitat elements are available Species associated with closed canopy forest also use early seral habitats…Even species that are normally associated with closed canopy forests use early seral forests if the appropriate habitat elements are availableIF appropriate habitat elements are available
5Species that specialize on conifers Hemlock LooperFew species are associated with early seral forests because they primarily use seedling/sapling conifers. Here are 2 examples that specialize on coniferous foliage. But red tree vole and red crossbills use older conifer forestsRed CrossbillRed Tree Vole
6Many conifer forest associates rely on diversity of plants On the other hand, many species that are thought of as conifer forest associates actually depend on non-coniferous plants to meet some of their needs, at least some of the timeSpruce Grouse: Feeds on berries and foliage of shrubs and forbs in conifer dominated forests east of Cascade Mts.; Vaccinium especially important in summer; feeds exclusively on conifer needles in winter; adequate ground cover and shrubs may be important influence on nest success.Spruce Grouse
7Elements of Quality Early Seral Habitat Early stages of succession in managed forests do not necessarily provide the same resources as natural, post-disturbance forests.
8Residual trees and snags D. VeselyResidual trees and snagsMatt LeeResidual trees and snags are a critical component of early seral habitat for many species; the presence of many species depends on the availability of these legacy structures.In particular, Woodpeckers love disturbance: it creates food for their prey: ants and beetlesSpecies such as (NOFL, LEWO, BBWO) specialize in open, post-disturbance habitats; create habitat for secondary cavity nesters
9Cavity-nesters in burned forests Fire-killed snags are important resource for foraging and nestingMany species respond negatively to salvage loggingAbundance of several woodpecker species increases after stand-replacing fires in dry east side forests: Hairy and black-backed woodpeckers, LEWO, NOFL, bluebirds.Removal of standing deadwood through salvage logging has negative effects on many of these species
10Bob AltmanThe combination of dead and dying trees in open habitats creates habitat that is uniquely suitable forAerial insectivores (many are cavity nesters); swallows, puma, wifl, bats, webl, atfl
11Early Seral Habitat for Reptiles D. VeselyEarly Seral Habitat for ReptilesBaskingPreyReptiles in early seral habitats: open for sunning; lots of prey
12Dead Wood as Refugia D. Vesely Dead wood created by disturbances provides refugia for species with low mobility, such as amphibiansLarge dead wood important in providing cover in otherwise exposed habitat; allows persistence of populationsDead wood in combination with dense cover and abundant seed production from pioneer species in a high-light environment creates suitable habitat for many granivores; e.g., mice, voles, sparrows, finches...D. Vesely
13Plant Diversity = Food Resources FoliageNectarFruitsSeedsMany species that rely directly on vegetation and mast for food are associated with early successional vegetation in forest gaps or regenerating stands. The light-rich environment of gaps results in greater production of flowers and fruits than the shaded matrix (Harrington et al., 2002).Vegetation in early seral stages tends to be fast growing and reproducing; i.e., lots of foliage, seeds, and fruits produced.Direct source of food for herbivores, granivores, pollinators, omnivores…
14Plant Diversity: foundation of food webs Non-coniferous vegetation not only supports species that directly consume it, but also higher level consumers.90% of the diet of northern spotted owls is composed of small mammals that are associated with non-coniferous vegetation, including wood rats and other rodents (Forsman et al., 1984; Table 1). Glenn et al. (2004) suggested that the presence of broad-leaved habitats in young forests may allow spotted owls to survive in landscapes with less late-seral forest than typically characterizes suitable habitat because of the positive influence on prey abundance.Early seral habitats provides the foundation for food webs that contribute to diversity at multiple trophic levels
15Matt LeeOther species that breed in older forests may use early seral habitat during the non-breeding seasonStudies from eastern hardwood forests have shown that early seral stages are important habitat for some bird species during the post-breeding season.Fledglings find cover and foodSome species fatten up on bountiful fruit before migrationSeveral species strongly associated with mature forest are among those that are abundant in early seral during the post-breeding seasonTo my knowledge, post-breeding habitat use has not been well-studied for many PNW species
16Arthropods Insect diversity correlated with plant diversity Deciduous species support more insectsInfluence of deciduous litter on soil food webs?Early seral stages also offer an abundance and diversity of arthropods for insectivores and small carnivoresSeveral species of shrew are associated with herbaceous, shrubby, and deciduous habitats;Insects can periodically be abundant on conifers, e.g. during outbreaks, but a diversity of herbs, shrubs, and hardwood trees ensures a diverse and stable resource for insectivores.
17Peter LaTourretteEarly seral habitats are primary breeding habitat for some species.Probable reasons: abundant food and cover; forage primarily on deciduous shrubs and treesMGWA and OCWA are common in early successional forests, but not in closed canopy mid-seral and old forests. Other shrub-associated species may be present throughout all stages of forest development as long as suitable habitat is present.Several species of neotropical migrant birds that rely on early seral or shrubby habitats have been experiencing population declines.
18Importance of Early Seral Broadleaf Communities to Avian Biodiversity Fontaine et al. 2008: “Broad-leaved hardwoods and shrubs appear to play a major role in structuring avian communities in the Klamath-Siskiyou region. In light of these results, extended periods of early seral broadleaf dominance and short-interval high-severity fires may be important to the conservation of avian biodiversity.”
1930 Year Trend for Swainson’s Thrush from Tillamook S.F. BBS Route We are seeing declines in populations of some shrub-associated species,No direct evidence that these declines are related to changes in the availability and quality of early seral habitat, but a connection does seem plausible.These declines suggest the need for a critical evaluation of the habitat requirements of early-seral and shrub–associated species
20Creating Early Seral Habitat? Why can’t we just clear cut a forest and instantly have quality early seral habitat that meets the needs of the previously mentioned species
21The reason we can’t just clear cut a forest and instantly have quality early seral habitat that meets the needs of the previously mentioned species is that Shrub development takes timefor shrubs to become old enough to produce flowers and fruit;C. Harrington: stem diameter positively correlated with number of flowers; large shrubs more likely to flower and produce seedMany intolerant shrub species can exist under closed canopies, but won’t flower and fruit unless sufficient light is available. So if canopy closes too soon, production is lost.Takes time for shrubs to develop thick stems and to be colonized by epiphytes, which add another whole layer of biological complexity to the system
22Understory vegetation has not been favored by past and present forest practices aimed at timber productionIn order to get conifers established quickly, and to ensure their dominance, Managers traditionally have “controlled” shrubs and hardwoods in young forestsShrubs are viewed as competitors for resources that should be going to the crop trees, but for many species of wildlife, non-coniferous vegetation is the essential, defining element of early seral.OFP rules mandate that conifers are reestablished on harvest units to specified densities within a specified time frame
23By the time a D-fir stand is years old, the conifer canopy makes up the main layer of vegetation, and any understory that survived early control has long been shaded out....
24Effects of Conifer-centric Forest Management on Early Seral Habitat Fewer residual structuresAltered vegetation compositionAlters patterns of food abundanceReduces diversity of food resourcesAlters food websReduced temporal spanSummary:Focus on conifer establishment hasReduced abundance of flowering, seed-producing vegetationreduced temporal span of early seral habitats = shortened duration of shrub dominance; consequences for migratory species that return to the same breeding location year after year?
25Consequences of reduced temporal span of early seral habitats Limit on shrub size and ageShortens duration of shrubby habitatReduced persistence of shrubs into mid-aged forestsBy focusing on the rapid establishment and dominance of conifers, the diversity and duration of the shrub stage is reducedUnder natural forest development scenario (i.e., without “vegetation control”) early seral habitat would be suitable for OCWA from stand age 5 - >30 (>25 generations).
26Restoration of Late Seral Forest Emphasizes large treesSize limit on harvest area on federal landsWhat will understory look like?Currently: no clearcuts on federal land. Size limit on area of partial harvests. Focus on restoration of late-seral forest structure, but again, focus is on trees.the restoration of old forest structure is a current focus of management on federal and state lands, primarily emphasizing the large-tree component of these forests. This approach is in danger of neglecting both early seral stages dominated by shrubs or deciduous trees, and the non-conifer understory components of mature forests.
27Keep all the piecesFeatures important in supporting diversity of wildlife could be present throughout all stages of forest developmentImportant to keep legacies, including shrubs, to carry through from one stage to the next.