Changes in the species richness, spatial pattern and species frequency associated with the decline of oak forest

Widespread encroachment of the fire-intolerant species Juniperus virginiana L. into North American grasslands and savannahs where fire has largely been removed has prompted the need to identify mechanisms driving J. virginiana encroachment. We tested whether encroachment success of J. virginiana is related to plant species diversity and composition across three plant communities. We predicted J. virginiana encroachment success would (i) decrease with increasing diversity, and (ii) J. virginiana encroachment success would be unrelated to species composition. We simulated encroachment by planting J. virginiana seedlings in tallgrass prairie, old-field grassland, and upland oak forest. We used J. virginiana survival and growth as an index of encroachment success and evaluated success as a function of plant community traits (i.e., species richness, species diversity, and species composition). Our results indicated that J. virginiana encroachment success increased with increasing plant richness and diversity. Moreover, growth and survival of J. virginiana seedlings was associated with plant species composition only in the old-field grassland and upland oak forest. These results suggest that greater plant species richness and diversity provide little resistance to J. virginiana encroachment, and the results suggest resource availability and other biotic or abiotic factors are determinants of J. virginiana encroachment success.

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The structural characteristics and climatic and human impacts of deciduous oak forests in China

Journal of Plant Ecology ◽

10.1093/jpe/rtab094 ◽

2021 ◽

Author(s):

Guoping Chen ◽

Qiong Cai ◽

Wenjing Fang ◽

Yuhao Feng ◽

Jiangling Zhu ◽

...

Keyword(s):

Species Richness ◽

Spatial Patterns ◽

Tree Species ◽

Structural Characteristics ◽

Tree Height ◽

Oak Forests ◽

Oak Forest ◽

Stem Density ◽

Shrub Species ◽

The Mean

Abstract Aims Deciduous oak forest is one of the typical vegetation types in temperate and subtropical mountain zones in China. However, the patterns and determinants of the structural characteristics of these forests remain poorly understood. Methods We investigated 682 oak forest plots across China to characterize the community structures of the oak forests and analyze the underlying factors controlling their spatial patterns. Important Findings Across all plots, the overall mean values were 13.7 cm, 10.0 m, 1468 stems/ha, and 24.3 m 2/ha for the diameter at breast height (DBH), height, stem density and total basal areas (TBA) of trees, respectively. The average species richness was 6 species/600 m 2, 10 species/100 m 2, and 4 species/1 m 2 for the tree, shrub and herb layers, respectively. As latitude increased, the mean tree height, stem density, TBA, tree species richness and shrub species richness decreased, and the mean DBH did not show a significant trend, while species richness of herbs increased significantly. Climatic and anthropogenic variables could explain more variations in mean DBH, mean tree height, TBA, tree species richness, shrub species richness than those in stem density and herb species richness. Further analysis showed that precipitation-related climatic factors were major factors shaping the spatial patterns of community structures. Our findings provide a basis for recognizing the biogeographic patterns of oak forest structures and their responses to global change in China.

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Relating sampling effort to the detection of spatial patterns of species richness in the soil seed bank of a mediterranean shrubland.

10.5194/egusphere-egu2020-18218 ◽

2020 ◽

Author(s):

Iván Torres ◽

José M. Moreno

Keyword(s):

Species Richness ◽

Spatial Pattern ◽

Spatial Patterns ◽

Seed Bank ◽

Soil Seed Bank ◽

Spherical Model ◽

Sampling Effort ◽

Long Distance ◽

Mediterranean Shrubland ◽

Heated Soil

<p>Studying the soil seed bank is a time and space-consuming task, and therefore only a small fraction of the soil is sampled. It is then critical to optimize sampling effort to reliably estimate soil seed bank properties. Here, we test whether the spatial patterns of species richness in the soil seed bank differ under increasing sampling effort. For this, we used data of germination from soils in a mediterranean shrubland in Central Spain. Two data sets were used, one of the seedlings emerging after heating the soil to break dormancy, and one with the combined germinations of heated and non-heated soil subsamples. We simulated increased sampling effort with sample-based rarefaction curves, extrapolating the species richness corresponding to a 2x and 3x increase in the number of individuals (seedlings) per sample. We then analyzed the spatial pattern of the original and extrapolated species richness using linear regression and semivariograms. Species richness increased by 34% and 52% in the 2x and 3x estimations, however the spatial pattern of species richness remained largely unchanged. For the long-distance spatial pattern, the slope of the plot-scale trend (i.e., the regression coefficient) increased only slightly with increasing sampling effort, while the adjusted R-squared of the regression decreased with increasing sampling effort. For the short-distance spatial pattern we could only fit spherical model semivariograms to the data from soils exposed to a heat shock, and the intensity of the spatial pattern (spatial dependence) increased very slightly with increased sampling effort. These results suggest that even with a doubled or tripled sampling effort, as provided by the simulations, the spatial pattern of species richness would have remained unchanged. We argue that increased effort in detecting species in the seed bank needs not necessarily improve the detection of spatial pattern.</p>

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Species richness effects on ecosystem multifunctionality depend on evenness, composition and spatial pattern

Journal of Ecology ◽

10.1111/j.1365-2745.2011.01918.x ◽

2011 ◽

Vol 100 (2) ◽

pp. 317-330 ◽

Cited By ~ 100

Author(s):

Fernando T. Maestre ◽

Andrea P. Castillo-Monroy ◽

Matthew A. Bowker ◽

Raúl Ochoa-Hueso

Keyword(s):

Species Richness ◽

Spatial Pattern ◽

Ecosystem Multifunctionality

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Spatial analysis of lichen species richness in a disturbed ecosystem (Niepołomice Forest, S Poland)

The Lichenologist ◽

10.1017/s0024282904014112 ◽

2004 ◽

Vol 36 (3-4) ◽

pp. 249-260 ◽

Cited By ~ 18

Author(s):

Paweł KAPUSTA ◽

Grażyna SZAREK-ŁUKASZEWSKA ◽

Józef KISZKA

Keyword(s):

Regression Analysis ◽

Species Richness ◽

Spatial Analysis ◽

Spatial Pattern ◽

Multiple Regression Analysis ◽

Multiple Regression ◽

Lichen Species ◽

Industrial Emissions ◽

Tree Stand ◽

Large Spatial Scale

The spatial pattern of lichen species richness was analyzed in a forest ecosystem impacted for 50 years by industrial emissions from a steelworks. Geostatistical tools were used to characterize the spatial pattern of the number of lichen species and multiple regression analysis was used to identify factors influencing it. Spatial analysis showed high variation of lichen species richness on a local scale, caused by patchiness of natural habitat factors (species composition of trees, their age, shade, etc.). On a large spatial scale, species richness differentiated the western from the eastern part of the forest. The western part, closer to the sources of pollution, had fewer species (average 6–10 per locality) than the eastern part (10–15 per locality). Multiple regression analysis was used to examine the relationships between the species richness of lichens and several environmental variables: input of ions with bulk precipitation (SO42−, NO−3, Cl−, Ca2+, Mg2+, Fe3+, Zn3+, Pb2+, Cd2+), distance to forest edge, tree stand age, and number of species per locality. Regression analysis was preceded by factor analysis for the input of ions to obtain uncorrelated variables. Regression explained 53% of the variation of lichen species richness. Highly significant predictor variables were the factor connected with the input of pollutants (Fe3+, Zn2+) emitted by the steelworks (negative effect) and the number of trees per locality (positive effect). Species richness was also affected by the age structure of the tree stand; more species were recorded in old forests.

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An Efficient Tool for the Maintenance of Thermophilous Oak Forest Understory—Sheep or Brush Cutter?

Forests ◽

10.3390/f11050582 ◽

2020 ◽

Vol 11 (5) ◽

pp. 582

Author(s):

Bogdan Jaroszewicz ◽

Małgorzata Jankowska-Błaszczuk ◽

Michał Żmihorski ◽

Tomasz Hałatkiewicz

Keyword(s):

Species Richness ◽

Plant Species ◽

Forest Floor ◽

Plant Species Richness ◽

Deciduous Forests ◽

Oak Forests ◽

Oak Forest ◽

Herb Layer ◽

Mechanical Removal ◽

Forest Herb

Research Highlights: Thermophilous oak forests are among the most species-rich forest ecosystems in Central Europe. In the temperate zone, they evolved from mixed deciduous forests due to centuries-long livestock grazing. The abandonment of traditional forms of landscape use resulted in a constant decline in the number of patches of these communities, their area and species richness, which has been ongoing for decades and calls for their urgent conservation. The commonly used approaches to the conservation of this community are the reestablishment of grazing or mechanical removal of undergrowth. However, there are a limited number of works comparing their effects on the forest herb layer separately and in combination. Background and Objectives: The purpose of our research was to evaluate the effectiveness of grazing, mechanical brush removal and their combination for the conservation of the oak forest herb layer. Materials and Methods: Our work was based on a fully crossed experimental design set in a 60-year-old oak forest. The individual and combined influences of sheep grazing and brush cutting on forest floor vegetation were compared to control plots. We surveyed plant species twice—before the application of treatments and one year later on 600 one-square-meter subplots selected randomly in the limits of twelve fenced 20 m × 20 m treated and untreated study plots. Results: Both grazing by sheep and mechanical removal served well for total plant species richness and their cover, if applied separately. But these effects were not additive—plant species richness and plant cover on plots with combined treatment did not differ from plots, where just a single treatment was applied. Application of both treatments (but separately) had positive influence on species cover of the target group of plants typical to xerothermic oak forests and non-target species of mixed deciduous forests. Mechanical removal allowed also for successful control of woody species. Active conservation measures resulted also in negative effects—we observed increase in the species richness and cover of ruderal species on grazed plots. Conclusions: Both tested methods can be used for active conservation of open oak forest understorey vegetation. The method of active conservation should be chosen depending on the goal and the species composition of the forest floor and undergrowth found at the beginning of the restoration process, however, combining of these treatments does not bring any extra advantage. In our opinion a monitoring of the reaction of vegetation on treatments is of paramount importance.

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Macrofungal diversity of a temperate oak forest: a test of species richness estimators

Canadian Journal of Botany ◽

10.1139/b99-055 ◽

1999 ◽

Vol 77 (7) ◽

pp. 1014-1027 ◽

Cited By ~ 14

Author(s):

John Paul Schmit ◽

John F Murphy ◽

Gregory M Mueller

Keyword(s):

Species Richness ◽

Species Diversity ◽

Deciduous Forest ◽

Hardwood Forests ◽

Oak Forest ◽

Species Richness Estimation ◽

Indiana Dunes ◽

Richness Estimators ◽

Diversity Estimates ◽

Better Than

Two 0.1-ha plots, each divided into 10 contiguous subplots, were established in a Quercus-dominated deciduous forest in the Indiana Dunes National Lakeshore. Macrofungi were surveyed on these plots at weekly intervals during the fruiting season over 3 years. During this survey 177 species were recorded, including 30 species inhabiting leaf litter, 36 ectomycorrhizal species, 29 non-mycorrhizal soil-inhabiting species, and 79 wood-inhabiting species. This species richness is comparable to, but slightly higher than, that reported by other plot-based studies undertaken in hardwood forests. We compared the ability of seven species-richness estimation techniques to determine the true species richness on these plots. While some estimators performed better than others, in general the estimations were too low based on the following year's data and were not consistent from year to year. We found some evidence of spatial autocorrelation of communities of fungi found in adjacent subplots. This indicates that the benefit of using contiguous subplots to increase the homogeneity of the area sampled needs to be balanced against the possibility of underestimating the species richness of an area because of spatial autocorrelation.Key words: macrofungi, species diversity, diversity estimates, Indiana Dunes.

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