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1.
Lucía Carrasco Andreas Gattinger Andreas Fließbach Antonio Roldán Michael Schloter Fuensanta Caravaca 《Microbial ecology》2010,60(2):265-271
The objective of this study was to compare the microbial community composition and biomass associated with the rhizosphere
of a perennial gramineous species (Lygeum spartum L.) with that of an annual (Piptatherum miliaceum L.), both growing in semiarid mine tailings. We also established their relationship with the contents of potentially toxic
metals as well as with indicators of soil quality. The total phospholipid fatty acid (PLFA) amount was significantly higher
in the rhizosphere soil of the annual species than in the rhizosphere soil of the perennial species. The fungal/bacterial
PLFA ratio was significantly greater in the perennial species compared to the annual species. The fatty acid 16:1ω5c, the
fungal/bacterial PLFA ratio and monounsaturated/saturated PLFA ratio were correlated negatively with the soluble contents
of toxic metals. The cyc/prec (cy17:0 + cy19:0/16:1ω7 + 18:1ω7) ratio was correlated positively with the soluble contents
of Pb, Zn, Al, Ni, Cd, and Cu. The results of the PLFA analysis for profiling microbial communities and their stress status
of both the plant species indicate that perennial and annual gramineous species appear equally suitable for use in programmes
of revegetation of semiarid mine tailings. 相似文献
2.
Deciduous forests may respond differently from coniferous forests to the anthropogenic deposition of nitrogen (N). Since fungi,
especially ectomycorrhizal (EM) fungi, are known to be negatively affected by N deposition, the effects of N deposition on
the soil microbial community, total fungal biomass and mycelial growth of EM fungi were studied in oak-dominated deciduous
forests along a nitrogen deposition gradient in southern Sweden. In-growth mesh bags were used to estimate the production
of mycelia by EM fungi in 19 oak stands in the N deposition gradient, and the results were compared with nitrate leaching
data obtained previously. Soil samples from 154 oak forest sites were analysed regarding the content of phospholipid fatty
acids (PLFAs). Thirty PLFAs associated with microbes were analysed and the PLFA 18:2ω6,9 was used as an indicator to estimate
the total fungal biomass. Higher N deposition (20 kg N ha−1 y−1 compared with 10 kg N ha−1 y−1) tended to reduce EM mycelial growth. The total soil fungal biomass was not affected by N deposition or soil pH, while the
PLFA 16:1ω5, a biomarker for arbuscular mycorrhizal (AM) fungi, was negatively affected by N deposition, but also positively
correlated to soil pH. Other PLFAs positively affected by soil pH were, e.g., i14:0, a15:0, 16:1ω9, a17:0 and 18:1ω7, while
some were negatively affected by pH, such as i15:0, 16:1ω7t, 10Me17:0 and cy19:0. In addition, N deposition had an effect
on the PLFAs 16:1ω7c and 16:1ω9 (negatively) and cy19:0 (positively). The production of EM mycelia is probably more sensitive
to N deposition than total fungal biomass according to the fungal biomarker PLFA 18:2ω6,9. Low amounts of EM mycelia covaried
with increased nitrate leaching, suggesting that EM mycelia possibly play an important role in forest soil N retention at
increased N input. 相似文献
3.
Structure of the Microbial Communities in Coniferous Forest Soils in Relation to Site Fertility and Stand Development Stage 总被引:10,自引:0,他引:10
T. Pennanen J. Liski E. Bååth V. Kitunen J. Uotila C.J. Westman H. Fritze 《Microbial ecology》1999,38(2):168-179
Abstract
The structure, biomass, and activity of the microbial community in the humus layer of boreal coniferous forest stands of different
fertility were studied. The Scots pine dominated CT (Calluna vulgaris type) represented the lowest fertility, while VT (Vaccinium vitis-idaéa type), MT (Vaccinium myrtillus type), and OMT (Oxalis acetocella–Vaccinium myrtillus type) following this order, were more fertile types. The microbial community was studied more closely by sampling a succession
gradient (from a treeless area to a 180-years-old Norway spruce stand) at the MT type site. The phospholipid fatty acid (PLFA)
analysis revealed a gradual shift in the structure of the microbial community along the fertility gradient even though the
total microbial biomass and respiration rate remained unchanged. The relative abundance of fungi decreased and that of bacteria
increased with increasing fertility. The structure of the bacterial community also changed along the fertility gradient. Irrespective
of a decrease in fungal biomass and change in bacterial community structure after clear-cutting, the PLFA analysis did not
show strong differences in the microbial communities in the stands of different age growing on the MT type site. The spatial
variation in the structure of the microbial community was studied at a MT type site. Semivariograms indicated that the bacterial
biomass, the ratio between the fungal and bacterial biomasses, and the relative amount of PLFA 16:1ω5 were spatially autocorrelated
within distances around 3 to 4 m. The total microbial and fungal biomasses were autocorrelated only up to 1 m. The spatial
distribution of the humus microbial community was correlated mainly with the location of the trees, and consequently, with
the forest floor vegetation.
Received: 9 November 1998; Accepted: 26 April 1999 相似文献
4.
Root controls on soil microbial community structure in forest soils 总被引:16,自引:0,他引:16
We assessed microbial community composition as a function of altered above- and belowground inputs to soil in forest ecosystems of Oregon, Pennsylvania, and Hungary as part of a larger Detritus Input and Removal Treatment (DIRT) experiment. DIRT plots, which include root trenching, aboveground litter exclusion, and doubling of litter inputs, have been established in forested ecosystems in the US and Europe that vary with respect to dominant tree species, soil C content, N deposition rate, and soil type. This study used phospholipid fatty-acid (PLFA) analysis to examine changes in the soil microbial community size and composition in the mineral soil (0–10 cm) as a result of the DIRT treatments. At all sites, the PLFA profiles from the plots without roots were significantly different from all other treatments. PLFA analysis showed that the rootless plots generally contained larger quantities of actinomycete biomarkers and lower amounts of fungal biomarkers. At one of the sites in an old-growth coniferous forest, seasonal changes in PLFA profiles were also examined. Seasonal differences in soil microbial community composition were greater than treatment differences. Throughout the year, treatments without roots continued to have a different microbial community composition than the treatments with roots, although the specific PLFA biomarkers responsible for these differences varied by season. These data provide direct evidence that root C inputs exert a large control on microbial community composition in the three forested ecosystems studied. 相似文献
5.
Linda T. A. van Diepen Erik A. Lilleskov Kurt S. Pregitzer R. Michael Miller 《Ecosystems》2010,13(5):683-695
Increased nitrogen (N) deposition caused by human activities has altered ecosystem functioning and biodiversity. To understand
the effects of altered N availability, we measured the abundance of arbuscular mycorrhizal fungi (AMF) and the microbial community
in northern hardwood forests exposed to long-term (12 years) simulated N deposition (30 kg N ha−1 y−1) using phospholipid fatty acid (PLFA) analysis and hyphal in-growth bags. Intra- and extraradical AMF biomass and total microbial
biomass were significantly decreased by simulated N deposition by 36, 41, and 24%, respectively. Both methods of extraradical
AMF biomass estimation (soil PLFA 16:1ω5c and hyphal in-growth bags) showed comparable treatment responses, and extraradical
biomass represented the majority of total (intra-plus extraradical) AMF biomass. N deposition also significantly affected
the microbial community structure, leading to a 10% decrease in fungal to bacterial biomass ratios. Our observed decline in
AMF and total microbial biomass together with changes in microbial community structure could have substantial impacts on the
nutrient and carbon cycling within northern hardwood forest ecosystems. 相似文献
6.
Therese Johansson Joakim Hjältén Fredrik Stenbacka Mats Dynesius 《Journal of Insect Conservation》2010,14(1):3-9
Boreal flat bugs include a high proportion of species that are considered negatively affected by forestry. Knowledge on the biology and habitat demands of individual species is generally limited. We examined the influence on flat bugs of stand-age and clear-cutting, comparing five classes of spruce stands. The five classes were: clear-cut, unthinned, and thinned (all three products of current clear-cutting forestry), mature managed and old-growth stands (these two had never been clear-cut). We also compared unburned and recently burned mature pine forest. Fire, but not stand age, had a pronounced effect on species richness and total abundance. Aradus depressus showed a significant association with older forest stands. Aradus betulae occurred only in clear-cuts and burned forest indicating that this species is favored by disturbance in general. Aradus lugubris, Aradus crenaticollis and Aradus brevicollis were found only in the burned forest. Aradus brevicollis has not previously been shown to be associated with fire. 相似文献
7.
Determinants of Soil Microbial Communities: Effects of Agricultural Management, Season, and Soil Type on Phospholipid Fatty Acid Profiles 总被引:29,自引:0,他引:29
Abstract
Phospholipid fatty acid (PLFA) profiles were measured in soils from organic, low-input, and conventional farming systems that
are part of the long term Sustainable Agriculture Farming Systems (SAFS) Project. The farming systems differ in whether their
source of fertilizer is mineral or organic, and in whether a winter cover crop is grown. Sustained increases in microbial
biomass resulting from high organic matter inputs have been observed in the organic and low-input systems. PLFA profiles were
compared to ascertain whether previously observed changes in biomass were accompanied by a change in the composition of the
microbial community. In addition, the relative importance of environmental variables on PLFA profiles was determined. Redundancy
analysis ordination showed that PLFA profiles from organic and conventional systems were significantly different from April
to July. On ordination plots, PLFA profiles from the low-input system fell between organic and conventional systems on most
sample dates. A group of fatty acids (i14:0, a15:0, 16:1ω7c, 16:1ω5c, 14:0, and 18:2ω6c) was enriched in the organic plots
throughout the sampling period, and another group (10Me16:0, 2OH 16:1 and 10Me17:0) was consistently lower in relative abundance
in the organic system. In addition, another group (15:0, a17:0, i16:0, 17:0, and 10Me18:0) was enriched over the short term
in the organic plots after compost incorporation. The relative importance of various environmental variables in governing
the composition of microbial communities could be ranked in the order: soil type > time > specific farming operation (e.g.,
cover crop incorporation or sidedressing with mineral fertilizer) > management system > spatial variation in the field. Measures
of the microbial community and soil properties (including microbial biomass carbon and nitrogen, substrate induced respiration,
basal respiration, potentially mineralizable nitrogen, soil nitrate and ammonium, and soil moisture) were seldom associated
with the variation in the PLFA profiles.
Received: 3 February 1997; Accepted: 7 August 1997 相似文献
8.
Flooding forested groundwater recharge areas modifies microbial communities from top soil to groundwater table 总被引:1,自引:0,他引:1
Kirsten Schütz Peter Nagel Walter Vetter Ellen Kandeler & Liliane Ruess 《FEMS microbiology ecology》2009,67(1):171-182
Subsurface microorganisms are crucial for contaminant degradation and maintenance of groundwater quality. This study investigates the microbial biomass and community composition [by phospholipid fatty acids (PLFAs)], as well as physical and chemical soil characteristics at woodland flooding sites of an artificial groundwater recharge system used for drinking water production. Vertical soil profiles to c . 4 m at two watered and one nonwatered site were analyzed. The microbial biomass was equal in watered and nonwatered sites, and considerable fractions (25–42%) were located in 40–340 cm depth. The microbial community structure differed significantly between watered and nonwatered sites, predominantly below 100 cm depth. Proportions of the bacterial PLFAs 16:1ω5, 16:1ω7, cy17:0 and 18:1ω9t, and the long-chained PLFAs 22:1ω9 and 24:1ω9 were more prominent at the watered sites, whereas branched, saturated PLFAs (iso/anteiso) dominated at the nonwatered site. PLFA community indices indicated stress response ( trans / cis ratio), higher nutrient availability (unsaturation index) and changes in membrane fluidity (iso/anteiso ratio) due to flooding. In conclusion, water recharge processes led to nutrient input and altered environmental conditions, which resulted in a highly active and adapted microbial community residing in the vadose zone that effectively degraded organic compounds. 相似文献
9.
P. J. Bottomley R. R. Yarwood S. A. Kageyama K. E. Waterstripe M. A. Williams K. Cromack Jr D. D. Myrold 《Plant and Soil》2006,289(1-2):35-45
Little information exists on the responses of soil fungal and bacterial communities in high elevation coniferous forest/open meadow ecosystems of the northwest United States of America to treatments that impact vegetation and soil conditions. An experiment was conducted in which soil cores were reciprocally transplanted between immediately adjacent forests and meadows at two high elevation (∼1,600 m) sites (Carpenter and Lookout) in the H.J. Andrews Experimental Forest located in the Cascade Mountains of Oregon. Half of the cores were placed in PVC pipe (closed) to prevent new root colonization, whereas the other cores were placed in mesh bags (open) to allow recolonization by fine roots. A duplicate set of open and closed soil cores was not transferred between sites and was incubated in place. After 2 year, soil cores were removed and changes in fungal and bacterial biomasses determined using light microscopy, and changes in microbial community composition determined by PLFA analysis, and by length heterogeneity PCR of the internal transcribed spacer region of fungal ribosomal DNA. At both sites soil microbial community structures had responded to treatments after 2 year of incubation. At Carpenter, both fungal and bacterial community structures of forest soil changed significantly in response to transfer from forest to meadow, with the shift in fungal community structure being accompanied by a significant decrease in the PLFA biomarker of fungal biomass,18:2ω6,9. At Lookout, both fungal and bacterial community structures of forest soil changed significantly in response to open versus closed core treatments, with the shift in the fungal community being accompanied by a significant decrease in the 18:2ω6,9 content of closed cores, and the shift in the bacterial community structure being accompanied by a significant increase in bacterial biomass of closed cores. At both sites, fungal community structures of meadow soils changed differently between open and closed cores in response to transfer to forest, and were accompanied by increases in the18:2ω6,9 content of open cores. Although there were no significant treatment effects on the bacterial community structure of meadow soil at either site, bacterial biomass was significantly higher in closed versus open cores regardless of transfer. 相似文献
10.
Long-Term Phosphorus Fertilization Impacts Soil Fungal and Bacterial Diversity but not AM Fungal Community in Alfalfa 总被引:8,自引:0,他引:8
Soil function may be affected by cropping practices impacting the soil microbial community. The effect of different phosphorus
(P) fertilization rates (0, 20, or 40 kg P2O5 ha−1) on soil microbial diversity was studied in 8-year-old alfalfa monocultures. The hypothesis that P fertilization modifies
soil microbial community was tested using denaturing gradient gel electrophoresis and phospholipids fatty acid (PLFA) profiling
to describe soil bacteria, fungi, and arbuscular mycorrhizal (AM) fungi diversity. Soil parameters related to fertility (soil
phosphate flux, soluble P, moisture, phosphatase and dehydrogenase assays, and carbon and nitrogen content of the light fraction
of soil organic matter) were also monitored and related to soil microbial ribotype profiles. Change in soil P fertility with
the application of fertilizer had no effect on crop yield in 8 years, but on the year of this study was associated with shifts
in the composition of fungal and bacterial communities without affecting their richness, as evidenced by the absence of effect
on the average number of ribotypes detected. However, variation in soil P level created by a history of differential fertilization
did not significantly influence AM fungi ribotype assemblages nor AM fungi biomass measured with the PLFA 16:1ω5. Fertilization
increased P flux and soil soluble P level but reduced soil moisture and soil microbial activity, as revealed by dehydrogenase
assay. Results suggest that soil P fertility management could influence soil processes involving soil microorganisms. Seasonal
variations were also recorded in microbial activity, soil soluble P level as well as in the abundance of specific bacterial
and fungal PLFA indicators of soil microbial biomass. 相似文献
11.
Yinlei Ma Yan Geng Yuanyuan Huang Yue Shi Pascal A. Niklaus Bernhard Schmid Jin-Sheng He 《Journal of Plant Ecology》2013,6(5):335
Aims Clear-cutting is a common forest management practice, especially in subtropical China. However, the potential ecological consequences of clear-cutting remain unclear. In particular, the effect of clear-cutting on soil processes, such as the carbon cycle, has not been quantified in subtropical forests. Here, we investigated the response of soil respiration (Rs) to clear-cutting during a 12-month period in a subtropical forest in eastern China.Methods We randomly selected four clear-cut (CC) plots and four corresponding undisturbed forest (UF) plots. Measurements of Rs were made at monthly time points and were combined with continuous climatic measurements in both CC and UF. Daily Rs was estimated by interpolating data with an exponential model dependent on soil temperature. Daily Rs was cumulated to annual Rs estimates.Important findings In the first year after clear-cutting, annual estimates of Rs in CC (508±23g C m ?2 yr-1) showed no significant difference to UF plots (480±12g C m ?2 yr-1). During the summer, soil temperatures were usually higher, whereas the soil volumetric water content was lower in CC than in UF plots. The long-term effects of clear-cutting on Rs are not significant, although there might be effects during the first several months after clear-cutting. Compared with previous work, this pattern was more pronounced in our subtropical forest than in the temperate and boreal forests that have been studied by others. With aboveground residuals off-site after clear-cutting, our results indicate that the stimulation of increasing root debris, as well as environmental changes, will not lead to a significant increase in Rs. In addition, long-term Rs will not show a significant decrease from the termination of root respiration, and this observation might be because of the influence of fast-growing vegetation after clear-cutting in situ . 相似文献
12.
Physiological Status and Community Composition of Microbial Mats of the Ebro Delta, Spain, by Signature Lipid Biomarkers 总被引:3,自引:0,他引:3
Navarrete A Peacock A Macnaughton SJ Urmeneta J Mas-Castellà J White DC Guerrero R 《Microbial ecology》2000,39(1):92-99
Abstract
Physiological status of microbial mats of the Ebro Delta (Tarragona, Spain) based on the extraction of lipids considered ``signature
lipid biomarkers' (SLB) from the cell membranes and walls of microorganisms has been analyzed. Data from a day–night cycle
show significant differences in viable cells countings (PLFA cells counts) ranging from 1.5 × 1010 to 5.0 × 1010 cells g−1 of sediment. Minimum values were observed at 18:00 and 6:00, when physicochemical conditions change drastically. The diversity
of the microbial community was assessed by GC/MS analysis of phospholipid fatty acids (PLFA). The ratio of PLFA, representative
of Gram-negative bacteria, comprises 47.8% of the total PLFA of the microbial mat community. The remaining PLFA was representative
of Gram-positive (10.0%), anaerobic (5.7%), and eukaryotic microorganisms (5.7%), and other common lipids. Two different approaches
were used as a comparative study to assess the physiological status of the microbial mats. Two parameters (cyclopropane fatty
acids/ω7c monoenoic fatty acids, and measurement of the trans/cis monoenoic PLFA ratio) showed a minimum at midnight, suggesting the highest microbial activity. Higher values were observed
at 18:00 and 6:00, coinciding with lower PLFA cell counts.
Received: 14 May 1999; Accepted: 6 September 1999; Online Publication: 24 March 2000 相似文献
13.
To determine how plant species richness impacts microbial assimilation of new photosynthate, and how this may be modified
by atmospheric N deposition, we analyzed the microbial assimilation of recent photosynthate in a 6-year-long field experiment
in which plant species richness, atmospheric N deposition, and atmospheric CO2 concentration were manipulated in concert. The depleted δ13C of fumigation CO2 enabled us to investigate the effect of plant species richness and atmospheric N deposition on the metabolism of soil microbial
communities in the elevated CO2 treatment. To accomplish this, we determined the δ13C of bacterial, actinobacterial, and fungal phospholipid fatty acids (PLFAs). In the elevated CO2 conditions of this study, the δ13C of bacterial PLFAs (i15:0, i16:0, 16:1ω7c, 16:1ω9c, 10Me16:0, and 10Me18:0) and the fungal PLFA 18:1ω9c was significantly
lower in species-rich plant communities than in species-poor plant communities, indicating that microbial incorporation of
new C increased with plant species richness. Despite an increase in plant production, total PLFA decreased under N deposition.
Moreover, N deposition also decreased fungal relative abundance in species-rich plant communities. In our study, plant species
richness directly increased microbial incorporation of new photosynthate, providing a mechanistic link between greater plant
detritus production in species-rich plant communities and larger and more active soil microbial community. 相似文献
14.
Microfungal diversity associated with Kindbergia oregana in successional forests of British Columbia
Species richness and species composition of microfungi associated with Oregon beaked moss (Kindbergia oregana) were studied at two forest chronosequences on southeast Vancouver Island, British Columbia, Canada. The purposes were to
investigate the effects of clear-cutting and the transformation of old-growth forests into secondary forests on microfungi
and the succession of microfungi in relation to long-term stand development. Green and brown parts of moss were collected
from the forest floor of Douglas-fir (Pseudotsuga menziesii) stands of four age classes: post-harvest regeneration (13–14 years), immature (50–51 years), and mature (85–101 years) stands,
and a control old-growth (296–324 years) stand, and used for the isolation of microfungi. A total of 49 microfungal species
were recorded. Study site, stand age, and moss parts significantly affected the species richness and species composition of
microfungi. The species richness of microfungi was significantly greater on brown than on green moss parts and lower in post-harvest
regenerations than in forest stands of the other age classes. The species composition of major microfungal species changed
gradually along the seral stages. Possible environmental and biological factors that could account for the succession of microfungi
were discussed. 相似文献
15.
Norifumi Shirasaka Takuya Umehara Yasunori Fukuda Hajime Yoshizumi Sakayu Shimizu 《Mycoscience》2005,46(6):329-333
We investigated the characteristics of desaturation in Trichoderma sp. AM076. Although 6,9,12-octadecatrienoic acid (18 : 3ω6) was detected when Trichoderma sp. AM076 was cultivated in the presence of 6,9-octadecadienoic acid (18 : 2ω9), the desaturation products of 6,9,12-octadecatrienoic
acid (18 : 3ω6) and 6-octadecenoic acid (18 : 1Δ6) were not detected. These results suggest that the double bonds at the Δ6
position of 18 : 3ω6 and 18 : 1Δ6 disturb their Δ15 and Δ9 desaturation, respectively. This fungus also introduced a double
bond at the Δ15 position of 9,12-hexadecadienoic acid (16 : 2ω4), thereby yielding a novel C16 polyunsaturated fatty acid
(PUFA) identified as 9,12,15-hexadecatrienoic acid (16 : 3ω1). Further investigations revealed that the mutant having enhanced
accumulation of linolenic aid (18 : 3ω3) accumulates 16 : 3ω1 as one of the major PUFAs, together with 9,12-octadecadienoic
acid (16 : 2ω4), when grown with palmitoleic acid (16 : 1ω7). These results suggest that, in this strain, the reaction that
catalyzes the conversion of linoleic acid to linolenic acid, similar to the conversion of 16 : 2ω4 to 16 : 3ω1, is not ω3
desaturation but Δ15 desaturation. 相似文献
16.
We estimated the biomass and growth of arbuscular mycorrhizal (AM) mycelium in sand dunes using signature fatty acids. Mesh
bags and tubes, containing initially mycelium-free sand, were buried in the field near the roots of the dune grass Ammophila arenaria L. AM fungal mycelia were detected at a distance of about 8.5 cm from the roots after 68 days of growth by use of neutral
lipid fatty acid (NLFA) 16:1ω5. The average rate of mycelium extension during September and October was estimated as 1.2 mm
day−1. The lipid and fatty acid compositions of AM fungal mycelia of isolates and from sand dunes were analysed and showed all
to be of a similar composition. Phospholipid fatty acids (PLFAs) can be used as indicators of microbial biomass. The mycelium
of G. intraradices growing in glass beads contained 8.3 nmol PLFAs per mg dry biomass, and about 15% of the PLFAs in G. intraradices, G. claroideum and AM fungal mycelium extracted from sand dunes, consisted of the signature PLFA 16:1ω5. We thus suggest a conversion factor
of 1.2 nmol PLFA 16:1ω5 per mg dry biomass. Calculations using this conversion factor indicated up to 34 μg dry AM fungal
biomass per g sand in the sand dunes, which was less than one tenth of that found in an experimental system with Glomus spp. growing with cucumber as plant associate in agricultural soil. The PLFA results from different systems indicated that
the biomass of the AM fungi constitutes a considerable part of the total soil microbial biomass. Calculations based on ATP
of AM fungi in an experimental growth system indicated that the biomass of the AM fungi constituted approximately 30% of the
total microbial biomass.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
17.
Edges resulting from forest clear-cutting and treefall gaps can affect plant populations and consequently the distribution
of species across landscapes. These two types of disturbance might interact to exacerbate or ameliorate “edge effects”, a
rarely tested possibility. We focused on the effects of distance from forest edge (0–10, 30–40, 60–70, and 190–200 m) and
habitat within forest fragments (treefall gaps and intact forest) on the early stages of development of Palicourea gibbosa and Faramea affinis, two common shrubs of montane forests in southwest Colombia. Seed germination and seedling growth did not change with distance
from forest edge. Within forest fragments, however, seed germination and seedling growth were higher in treefall gaps than
in intact forest understory for both species. In contrast, seed predation was influenced by distance from forest edge and
in P gibbosa it depended on habitat. Seed predation was highest in the forest interior (190–200 m from forest edge) and in P. gibbosa this was true only in treefall gap habitats. These results suggest that animal mediated processes such as post-dispersal
seed predation are more likely than physiological processes to be affected by anthropogenic edges. Our results provide some
evidence that treefall gaps may interact with “edge effects”, however, they are inconclusive as to whether they exacerbate
or ameliorate them.
Received: 31 August 1998 / Accepted: 18 February 1999 相似文献
18.
María Vanessa Lencinas Guillermo Martínez Pastur Emilce Gallo Juan Manuel Cellini 《Journal of Insect Conservation》2014,18(3):479-495
Variable retention is an alternative silvicultural approach to timber forest management, which consist in a regeneration treatment with different degrees and patterns of stand retention. It has been proposed to mitigate harmful effects of harvesting, but effectiveness in insect conservation remains unknown in southern Patagonian Nothofagus pumilio forests. Here, the objectives were to: (1) define a baseline of insect diversity in old-growth forests along a site quality gradient (high, medium and low, associated to the forest productivity of each site); (2) evaluate stands with different retention treatments [aggregated (AR) surrounded by dispersed (DR) retention, and aggregated retention surrounded by clear-cut (CC)] and to compare with old-growth unmanaged forests (OGF); and (3) assess temporal changes during the first 4 years after harvesting (YAH). In a long term forest research plot, mobile epigean insect richness and relative abundance were characterized and classified in seven response type groups, using a wide spectrum sampling set. Data analyses included parametric and permutational ANOVAs, multivariate classification and ordinations. There were found 79 species before harvesting, and that richness was not related to site quality. After harvesting, 84 new species were added considering all treatments along the first four sampled YAH, of which 65 % were added to OGF, while in harvested sites richness and abundance directly diminished with retention degree (OGF > AR > DR > CC) due to incoming species cannot compensate the lost of them. However, fluctuations in diversity were observed along the YAH. Therefore, harvesting reduces insect richness in N. pumilio forests independently of the treatment, but the original insect assemblage significantly changes due to loss of sensitive species and introduction of others from surrounding environments. Despite this, inclusion of aggregates greatly diminished harvesting impacts because insect assemblage is favoured when structural complexity is preserved, conserving richness and abundance at similar levels than in old-growth forests. However, more studies are necessary to evaluate effects of different aggregate size, shape and distribution into harvested forests, as well as their fragmentation and connectivity at landscape level. 相似文献
19.
Population responses of Japanese serow (Capricornis crispus) to clear-cut logging and planted tree growth were studied by a direct count of the number observed in three areas, Takiyama
(305 ha), Gentouziro (270 ha), and Tanokashira (324 ha), near Wakinosawa Village, Aomori Prefecture, Japan, during 1976–89.
At Takiyama, a mature mixed forest ofThujopsis dolabrata var.hondai andFagus crenata decreased from 73 to 39% coverage of the area due to clear-cutting during 1978–83. The serow population maintained a relatively
low stable density (3–6 individuals per km2) until 1985–87, and increased 5–10 years after the clear-cutting, reaching 9–10 km−2 in 1988. At Gentouziro and Tanokashira, young plantations of Japanese cedar (Cryptomeria japonica) covered about half of each area. The population densities between 1980 and 1983 were relatively high (14–19 km−2), but declined thereafter, reaching 10–14 km−2 in 1988–89. These results indicated that the density increase resulted from an improvement of food supply due to growth of
scrub following the clear-cutting, and that the density decline resulted from a habitat change due to growth of planted Japanese
cedar and a decrease in the food supply. In Wakinosawa Village, serow density began to increase 5–10 years after forest cutting,
and the high population density, about three- or six-fold larger than that in mature forest, is expected to be maintained
for about 20 years after logging. 相似文献
20.
Jouni Sorvari Marja-Katariina Haatanen Salla-Riikka Vesterlund 《Journal of Insect Conservation》2011,15(5):727-731
The survival of insects during diapause may be affected by overwintering temperature and other environmental stress, such
as anthropogenic habitat degradation. We experimentally studied the effects of overwintering temperature (+1 and +7°C) and
commercial forest clear-cutting on the overwintering survival of the forest-dwelling wood ant Formica aquilonia. We found that both the higher overwintering temperature and clear-cutting lowered the overwintering survival and body fat
resources of Formica aquilonia. The survival and body fat resources were highest in lower temperature treatment forest nests and lowest in higher temperature
treatment clear-cut nests. The overall survival of ants increased with higher body fat resources. It is possible that both
forest clear-cutting and higher winter temperature due to possible climate warming may increase the wintertime mortality of
wood ants and other forest-dwelling ants. 相似文献