Effects of New Forest Management Strategies on Squirrel Populations

Carey, Andrew B.

doi:10.2307/2640999

Cited by 58 publications

(90 citation statements)

References 34 publications

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“…comm.). Flying squirrels were twice as abundant when legacy trees were retained in managed areas (Carey, 2000) and their diet was found to be more diverse in legacy stands (Carey et al, 2002).…”

Section: Discussionmentioning

confidence: 99%

Individual legacy trees influence vertebrate wildlife diversity in commercial forests

Mazurek

Zielinski

2004

Forest Ecology and Management

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Old-growth forests provide important habitat elements for many species of wildlife. These forests, however, are rare where lands are managed for timber. In commercial forests, large and old trees sometimes exist only as widely-dispersed residual or legacy trees. Legacy trees are old trees that have been spared during harvest or have survived stand-replacing natural disturbances. The value of individual legacy trees to wildlife has received little attention by land managers or researchers within the coast redwood (Sequoia sempervirens) region where 95% of the landscape is intensively managed for timber production. We investigated the use of individual legacy old-growth redwood trees by wildlife and compared this use to randomly selected commercially-mature trees. At each legacy/control tree pair we sampled for bats using electronic bat detectors, for small mammals using live traps, for large mammals using remote sensor cameras, and for birds using time-constrained observation surveys. Legacy old-growth trees containing basal hollows were equipped with 'guano traps'; monthly guano weight was used as an index of roosting by bats. The diversity and richness of wildlife species recorded at legacy trees was significantly greater than at control trees (Shannon index ¼ 2:81 versus 2.32; species ¼ 38 versus 24, respectively). The index of bat activity and the number of birds observed was significantly greater at legacy trees compared to control trees. We found no statistical differences between legacy and control trees in the numbers of small mammals captured or in the number of species photographed using remote cameras. Every basal hollow contained bat guano and genetic methods confirmed use by four species of bats. Vaux's swifts (Chaetura vauxi), pygmy nuthatches (Sitta pygmaea), violet-green swallows (Tachycineta thalassina), and the longlegged myotis (Myotis volans) reproduced in legacy trees. As measured by species richness, species diversity, and use by a number of different taxa, legacy trees appear to add significant habitat value to managed redwood forests. This value probably is related to the structural complexity offered by legacy trees. The presence of a basal hollow, which only occur in legacy trees, was the feature that appeared to add the greatest habitat value to legacy trees and, therefore, to commercial forest stands. The results of our study call for an appreciation for particular individual trees as habitat for wildlife in managed stands. This is a spatial resolution of analysis that, heretofore, has not been expected of managers. The cumulative effects of the retention of legacy trees in commercial forest lands could yield important benefits to vertebrate wildlife that are associated with biological legacies. #

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Section: Discussionmentioning

confidence: 99%

Individual legacy trees influence vertebrate wildlife diversity in commercial forests

Mazurek

Zielinski

2004

Forest Ecology and Management

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“…Stands with high structural diversity and overstory cover, at least of the dominant tree layer, provide decreased predation risk for tree squirrels (Vahle and Patton 1983;Carey 2000). Holloway and Malcolm (2006) reported that these habitat attributes were related to higher numbers of both sciurids in relatively intact coniferous and deciduous forests in Ontario.…”

Section: Introductionmentioning

confidence: 99%

“…These sciurids function as indicators of ecological productivity via their foraging on, and dissemination of, coniferous seeds and ectomycorrhizal fungi (Maser and Maser 1988;Carey 2000). They also serve as prey for raptors and mammalian carnivores (Carey and Harrington 2001; ).…”

Section: Introductionmentioning

confidence: 99%

“…glauca (Beissn.) Franco), interior spruce (Picea engelmannii × P. glauca (Moench) Voss), or other coniferous trees, snags, and abundant coarse woody debris seem to maintain both species in managed stands (Carey 2000;Smith et al 2003). However, Holloway et al (2012) concluded that the current minimum retention standard of 15% basal area of green-tree retention (GTR) will not provide suitable habitat for G. sabrinus in the PNW of the U.S.A.…”

Section: Introductionmentioning

confidence: 99%

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Tree squirrel abundance and demography in managed coniferous forests of British Columbia are within the range of natural fluctuations of old-growth stands

Sullivan

Ransome²,

Sullivan³

et al. 2017

Can. J. For. Res.

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Abstract:The American red squirrel (Tamiasciurus hudsonicus Exrleben) and northern flying squirrel (Glaucomys sabrinus Shaw) are important mammal species in coniferous forests that are widely distributed across temperate and boreal ecological zones. Although T. hudsonicus and G. sabrinus apparently prefer late-successional forests, their population dynamics show no clear pattern in young second-growth and old-growth conifer forests. We used a compilation of study results that had standardized methodology and sampling effort to compare tree squirrel responses across a range of forest conditions. We tested the hypotheses (H) that abundance, reproduction, recruitment, and survival would be higher in (H 1 ) old-growth than second-growth stands, (H 2 ) unthinned than thinned second-growth stands, and (H 3 ) lightly than heavily thinned stands. Tree squirrel populations in old-growth stands were considered the "standard" treatment to which other treatments in second-growth stands (unthinned and variously thinned) were compared. Thinned stands were grouped into low, medium, and high densities of trees. Datasets from seven published studies included 2804 Tamiasciurus and 837 G. sabrinus individuals, 25 study years, and 158 trapping periods. Mean abundance of Tamiasciurus was similar among treatment stands, ranging from 0.62 to 1.29·ha −1 . Mean numbers of G. sabrinus were highest in old-growth stands at 0.65·ha −1 , followed by the low-and medium-density stands at 0.50·ha −1 , the high-density stands at 0.25·ha −1 , and finally the unthinned second-growth stands at a low of 0.12·ha −1 . In terms of effect size, mean proportional change in abundance, relative to that within old-growth stands, of both squirrel species in the three thinned stands were within the range of natural fluctuations in old-growth stands. Populations of Tamiasciurus in the unthinned stands were not within the range of fluctuations in the old-growth stands. Mean number of successful pregnancies and total recruits were similar among stands for Tamiasciurus, with variability in female breeding and winter survival. Mean number of recruits of G. sabrinus was highest in old-growth stands with no other differences in demographic attributes among stands. The biological significance of these differences in demographic variables was small in terms of effect sizes. Tamiasciurus and G. sabrinus seem to persist in a relatively broad range of young managed forest habitats, as well as in old-growth stands.Key words: coniferous forests, Glaucomys sabrinus, managed stands, old-growth forest, population dynamics, Tamiasciurus.Résumé : L'écureuil roux américain (Tamiasciurus hudsonicus Exrleben) et le grand polatouche (Glaucomys sabrinus Shaw) sont deux espèces de mammifères d'importance dans les forêts de conifères qui couvrent une grande partie des biomes tempérés et boréaux. Mis à part le fait que T. hudsonicus et G. sabrinus semblent préférer les forêts de fin de succession, leur dynamique des populations ne montre pas de tendances nettes dans les jeunes forêts d...

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“…For example, large down wood on the riparian forest floor provides breeding habitat and cover essential for herpetofauna (Whiles and Grubaugh 1993, Welsh and Ollivier 1998, Semlitsch and Bodie 2003. Similarly, standing dead trees increase the structural complexity of a forest and provide nesting, roosting and feeding habitat for a suite of cavity nesting birds and mammals (Maser et al 1988, Loeb 1994, Carey 2000, Erickson and West 2003. For aquatic species, instream wood is essential to the maintenance of habitat because it forms pools, traps and sorts gravels, increases hyporheic exchange, moderates stream temperature, provides cover and increased habitat complexity (Montgomery et al 1995, Beechie and Sibley 1997, Moore et al 2005.…”

Section: Introductionmentioning

confidence: 99%

Using reference conditions in ecosystem restoration: an example for riparian conifer forests in the Pacific Northwest

2012

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Abstract. Quantifying the attributes of reference sites is a crucial problem in the restoration of ecosystems, driving both the evaluation of current conditions and the setting of management targets for specific points in the future. Restoration of riparian ecosystems, particularly those dominated by conifers, has become a priority because of the numerous ecosystem services they provide, including a high number of vertebrate species in population decline that utilize these structurally complex forests. By way of example, we illustrate a three-step process to assess the effects of proposed riparian ecosystem restoration efforts: (1) identify reference sites (2) quantify metrics that describe the reference sites, and (3) use models to predict the likely effects of restoration actions relative to reference conditions. To this end, we identified 117 natural, late-successional conifer dominated stands from existing forest inventories in the Pacific Northwest for the purpose of establishing reference conditions. We did this to establish quantitative metrics for structural attributes essential to the maintenance of biodiversity in these forests, and to assess whether there were any important quantitative differences between upland and riparian forests or whether upland and riparian forest reference sites could be used interchangeably. Both forest types were generally similar, but riparian stands had higher average live tree wood volumes and basal areas, suggesting they may be growing on sites that are more productive. Both riparian and upland forests had abundant large diameter (.50 cm) live trees and snags. Collectively, our data suggest that mature, late-successional conifer dominated forests have well developed structural characteristics in terms of abundant large trees in the overstory, abundant large snags, and a well-developed understory of shade-tolerant trees. We modeled the growth of young conifer stands to assess whether a common restoration treatment would accelerate development of structural characteristics typical of reference conditions. We found that left untreated, the stands followed a trajectory towards developing forest structure similar to the average reference condition. In contrast, the restoration treatment followed a developmental trajectory along the outside range of reference conditions.

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Effects of New Forest Management Strategies on Squirrel Populations

Cited by 58 publications

References 34 publications

Individual legacy trees influence vertebrate wildlife diversity in commercial forests

Individual legacy trees influence vertebrate wildlife diversity in commercial forests

Tree squirrel abundance and demography in managed coniferous forests of British Columbia are within the range of natural fluctuations of old-growth stands

Using reference conditions in ecosystem restoration: an example for riparian conifer forests in the Pacific Northwest

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