scholarly journals Effects of Savanna Restoration on the Foraging Ecology of Insectivorous Songbirds

The Condor ◽  
2005 ◽  
Vol 107 (4) ◽  
pp. 879-888 ◽  
Author(s):  
Sarah C. Hartung ◽  
Jeffrey D. Brawn

Abstract We studied the foraging behavior of insectivorous songbirds during the breeding season at four sites in Illinois, each with restored open-canopy savanna habitat (65% mean canopy closure) and closed-canopy forests (89% mean canopy closure). We sampled and compared apparent tree species preference, foliage layer preference, and proportional use of different prey-attack maneuvers in the two habitats. In closed-canopy forests, three of nine songbird species foraged in black oak (Quercus velutina) and white oak (Q. alba) more than expected based on availability, and foraged less than expected in shade-tolerant trees such as sugar maple (Acer saccharum) and red elm (Ulmus rubra). Four species also displayed apparent preferences for black locust (Robinia pseudoacacia) and hackberry (Celtis occidentalis). In contrast, songbirds used tree species according to availability in open-canopy habitat. We observed apparent preferences for the shrub and subcanopy vegetation layers (0–5 m and 6–10 m) in open-canopy habitat and apparent preferences for the subcanopy and lower canopy vegetation layers (6–10 m and 11–15 m) in closed-canopy forests. Relative use of prey-attack maneuvers in open versus closed-canopy habitat was significantly different for the Eastern Wood-Pewee (Contopus virens) and the Great Crested Flycatcher (Myiarchus crinitus), but not for foliage-gleaning species. These results suggest that restoration of oak savannas has important effects on the habitat use and foraging ecology of selected insectivorous birds.

Microbiology ◽  
2011 ◽  
Vol 157 (10) ◽  
pp. 2904-2911 ◽  
Author(s):  
Michael Wyrebek ◽  
Cristina Huber ◽  
Ramanpreet Kaur Sasan ◽  
Michael J. Bidochka

Here we tested the hypothesis that species of the soil-inhabiting insect-pathogenic fungus Metarhizium are not randomly distributed in soils but show plant-rhizosphere-specific associations. We isolated Metarhizium from plant roots at two sites in Ontario, Canada, sequenced the 5′ EF-1α gene to discern Metarhizium species, and developed an RFLP test for rapid species identification. Results indicated a non-random association of three Metarhizium species (Metarhizium robertsii, Metarhizium brunneum and Metarhizium guizhouense) with the rhizosphere of certain types of plant species (identified to species and categorized as grasses, wildflowers, shrubs and trees). M. robertsii was the only species that was found associated with grass roots, suggesting a possible exclusion of M. brunneum and M. guizhouense. Supporting this, in vitro experiments showed that M. robertsii conidia germinated significantly better in Panicum virgatum (switchgrass) root exudate than did M. brunneum or M. guizhouense. M. guizhouense and M. brunneum only associated with wildflower rhizosphere when co-occurring with M. robertsii. With the exception of these co-occurrences, M. guizhouense was found to associate exclusively with the rhizosphere of tree species, predominantly Acer saccharum (sugar maple), while M. brunneum was found to associate exclusively with the rhizosphere of shrubs and trees. These associations demonstrate that different species of Metarhizium associate with specific plant types.


1984 ◽  
Vol 62 (12) ◽  
pp. 2425-2428 ◽  
Author(s):  
Uldis Roze

Winter feeding of individual porcupines (Erethizon dorsatum L.) was studied in the northern Catskill Mountains of New York by following individual feeding trails in the snow. The study population as a whole fed primarily on beech (Fagus grandifolia) and sugar maple (Acer saccharum) and less frequently on eight other tree species. Individual porcupines limited their feeding to one or two species. An individual's primary food choice corresponded to the numerically most abundant tree species in its foraging area; its secondary food choice could not be related to relative density nor to relative basal area.


2007 ◽  
Vol 139 (5) ◽  
pp. 751-755 ◽  
Author(s):  
Ann E. Hajek ◽  
David M. Kalb

AbstractStriped maple (Acer pensylvanicum L.) was compared with sugar maple (Acer saccharum Marsh.) for use in rearing Asian longhorned beetles (Anoplophora glabripennis (Motschulsky)). Adult females lived longer when caged with twigs and small bolts harvested from A. pensylvanicum during late spring through early fall than with material from A. saccharum collected at the same time. Females had a shorter life-span when fed plant material from either tree species harvested from late fall through winter than with plant material from A. pensylvanicum harvested from late spring through early fall. Female A. glabripennis laid more viable eggs when provided with A. pensylvanicum rather than A. saccharum. Regardless of which of these two tree species females had experienced previously, they always chose to lay more eggs in A. pensylvanicum than in A. saccharum. Rearing A. glabripennis on A. pensylvanicum is therefore more efficient, especially when twigs and wood collected from late spring through early fall are used.


2003 ◽  
Vol 20 (2) ◽  
pp. 85-91 ◽  
Author(s):  
John M. Lhotka ◽  
James J. Zaczek

Abstract This study investigated whether soil scarification during the presence of abundant white oak (Quercus alba L.) acorns and other mast could be used to increase the density of oak reproduction and reduce competitive midstory species in a mid-successional mixed-oak upland forest. The study was conducted in a 7.3 ha forest with a mature oak overstory and a well-developed midstory of sugar maple (Acer saccharum Marsh.) and pawpaw (Asmina triloba Dunal.) in southern Illinois. The soil scarification was conducted in the autumn after acorn dissemination using a crawler tractor with a six-tooth brush rake. One growing season after treatment, significantly higher numbers of oak seedlings, primarily white oak, were present in the scarified plots (5,164 ha-1) compared to the control plots (1,273 ha-1). Seedling density of all other species classes did not differ between treatments. Scarification affected 61% of midstory trees and thus reduced their density and competitive position. Of these trees, 21% of stems were completely removed by the scarification treatment. Results suggest that, in the presence of abundant acorns, scarification may increase the number of new oak germinants in stands lacking advanced oak reproduction. Finally, because scarification increased the density of oak seedlings and reduced competing midstory trees, it can play a role in promoting the establishment of advanced oak reproduction. North. J. Appl. For. 20(2):85–91.


2017 ◽  
Vol 47 (7) ◽  
pp. 875-882 ◽  
Author(s):  
M.A. Arthur ◽  
K.C. Weathers ◽  
G.M. Lovett ◽  
M.P. Weand ◽  
W.C. Eddy

Beech bark disease (BBD) has demonstrable ecosystem consequences for eastern US forests stemming from American beech (Fagus grandifolia Ehrh.) mortality, often leading to increased dominance by its competitor, sugar maple (Acer saccharum Marsh.). We hypothesized that this BBD-induced shift in tree species composition leads to changes in soil acid–base chemistry, mediated through differences in leaf litter chemistry of the two species. Using a sequence of plots representing the progression of the disease in the Catskill Mountains, NY, USA, we examined the influence of tree species composition shift on soil chemistry. The BBD impact on tree species composition was confounded by variability in substrate (or nonexchangeable soil) calcium (Ca). While substrate Ca explained much of the variation in acid–base chemistry, increasing BBD was associated with increasing forest floor exchangeable Ca, sum of base cations, base saturation, cation-exchange capacity, and decreasing hydrogen. An apparent threshold effect of substrate Ca on sugar maple litter Ca concentration suggests that underlying soil Ca availability may contribute to the spatial extent and timeframe of BBD-induced shifts in species composition. The species compositional shift is a mechanism contributing to a vegetation effect on soil acid–base status and may partially counteract soil acidification in this acid deposition impacted region.


1982 ◽  
Vol 60 (7) ◽  
pp. 1279-1281 ◽  
Author(s):  
Jean Cypher ◽  
Douglas H. Boucher

We tested the hypothesis that coexistence of forest tree species is promoted by canopy-dependent seedling growth, such that each tree species grows faster under adults of a different species. The study was carried out in the forest of Mont Saint Hilaire, P.Q., using seedlings of American beech (Fagus grandifolia) and sugar maple (Acer saccharum). The main hypothesis was confirmed, while an auxiliary hypothesis for coexistence involving differential longevity and light gap growth was not confirmed.


1987 ◽  
Vol 5 (3) ◽  
pp. 136-140
Author(s):  
Frank S. Santamour ◽  
Alice Jacot McArdle

Two nematodes, one stylet-bearing and allied to the Aphelenchoides fragariae complex and the non-stylet species Panagrolaimus subelongatus, were isolated from the disrupted bark on main trunks and branches of young flowering dogwood (Cornus florida L.) trees exhibiting symptoms of “dogwood canker” disease. Similar nematodes were isolated from burls on the trunks of Siberian elm (Ulmus pumila L.), Higan cherry (Prunus subhirtella Miq.), red oak (Quercus rubra L.) and black locust (Robinia pseudoacacia L.), whereas only the Panagrolaimus species was found in abnormal tumorous growths on the trunks of the Green Mountain cultivar of sugar maple (Acer saccharum Marsh. ‘Green Mountain’). Nematodes were recovered 2 months after inoculation into young dogwood stems in June, 1983 but none could be detected after the inoculated trees had been subjected to winter temperatures as low as −22°C (−4°F) even though nematodes in established cankers survived under the same conditions. Inoculations made in July, 1984 into callus tissue developed after wounding in 1983 or 1984 produced canker-like symptoms but the nematodes were not reisolated in 1985. The total number of nematodes per canker was low and older cankers often yielded no nematodes, even though the canker persisted.


HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1143b-1143
Author(s):  
Orville M. Lindstrom

The cold hardiness of seven deciduous hardwoods, red maple (Acer rubrum L.), white oak, (Quercus alba L.), green ash (Fraxinus pennsylvanica Marsh.), sweetgum (Liguidambar stryaciflua L.), sugar maple (Acer saccharum Marsh.), river birch (Betula nigra L.) and black cherry (Prunus serotina Ehrh.) were evaluated weekly during the fall, winter and spring for three consecutive years. All trees evaluated were established (20-40 years old) and locatd on the Georgia Station Griffin, GA. Each species developed a maximum cold hardiness of at least -30 C by mid-January or early February each season. Response to temperature fluctuations varied with species. Red maple, for example, lost less cold hardiness due to warm mid-winter temperatures than the other species tested, while white oak tended to respond more quickly to the temperature fluctuations. Data will be presented comparing the response of cold hardiness to mid-winter temperature fluctuations for each species for the three year period.


2011 ◽  
Vol 28 (1) ◽  
pp. 50-53 ◽  
Author(s):  
Eric J. Holzmueller ◽  
John W. Groninger ◽  
Charles M. Ruffner ◽  
Trevor B. Ozier

Abstract Light harvesting and no cutting are two common management regimes in oak-dominated forests in the Ozark Hills of southern Illinois. We compared changes in overstory stand composition between 1980 and 2000 among forest inventory plots that were lightly harvested after initial sampling and plots that were uncut during the same time period. Total white oak (Quercus alba L.) basal area increased for both management regimes. Black oak (Quercus velutina Lam.) overstory density decreased, and sugar maple (Acer saccharum Marsh.) and American beech (Fagus grandifolia Ehrh.) density increased for both management regimes. Although overall density of oak was maintained by both management regimes, species and diameter class-specific response varied. Additional silvicultural activities may be necessary to sustain oak in both lightly harvested and uncut plots, with light harvesting providing opportunities to at least partially offset costs.


2009 ◽  
Vol 141 (5) ◽  
pp. 515-520 ◽  
Author(s):  
Briana Schroeder ◽  
Christopher M. Buddle ◽  
Michel Saint-Germain

AbstractWe studied the effects of forest height and forest gap on assemblages of flying beetles in an American beech (Fagus grandifolia Ehrh. (Fagaceae) – sugar maple (Acer saccharum Marsh. (Aceraceae)) forest in Quebec. From June until August of 2005, beetles were collected in Lindgren funnel traps placed in the canopy (20–25 m height) and upper understorey (3–5 m height) in proximity to five forest gaps (15–30 m in diameter) (at the edge of the forest opening or within the closed-canopy forest). We collected 1852 beetles representing 38 families and 172 species. Based on rarefaction curves, species richness was significantly higher in the canopy than in the upper understorey. Nonmetric multidimensional scaling ordination revealed a change in species composition in relation to vertical stratification but not to the forest gaps. Our findings confirmed the importance of the vertical forest gradient to overall diversity of forest coleopterans.


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