scholarly journals Modern pollen – vegetation – plant diversity relationships across large environmental gradients in northern Greece

The Holocene ◽  
2021 ◽  
pp. 095968362110604
Author(s):  
Carolina Senn ◽  
Willy Tinner ◽  
Vivian A Felde ◽  
Erika Gobet ◽  
Jacqueline FN van Leeuwen ◽  
...  
Keyword(s):  
Plant Diversity ◽  
Deciduous Forest ◽  
Environmental Gradients ◽  
Sampling Site ◽  
Sediment Surface ◽  
Northern Greece ◽  
Biodiversity Crisis ◽  
Modern Pollen ◽  
Straightforward Application ◽  
Vegetation Surveys

Past vegetation and biodiversity dynamics, reconstructed using palaeoecological methods, can contribute to assessing the magnitude of the current biodiversity crisis and anticipating future risks and challenges. Among the different palaeoecological techniques, pollen analysis is probably the most widely used to reconstruct vegetation and plant diversity changes through time. Such reconstructions demand robust and comprehensive calibration studies addressing the pollen representation of extant vegetation to be sound. However, calibration studies are rare in the Mediterranean biodiversity hotspot, particularly regarding plant diversity. Here, we contribute to filling this gap by investigating the modern pollen signature of Mediterranean vegetation across a large environmental gradient in northern Greece. At each sampling site ( n = 61), we quantitatively compared the composition and diversity of plant (vegetation surveys) and pollen assemblages (moss/topsoil samples) using numerical techniques. Further, we compared these terrestrial pollen assemblages with those from lake sediment surface samples of the same region. We found an overall good match between plant and pollen assemblages, with maquis and mixed deciduous forest displaying particularly distinct pollen signatures. In contrast, the high regional importance of pines and oaks and their large pollen production blurred the pollen representation of other forested vegetation types and of shrublands and grasslands. Plant and pollen richness and their evenness showed similar declining trends with increasing altitude, but plant and pollen evenness bore a better match than richness. A more detailed vegetation-specific view on the data suggests that pine pollen seriously affected pollen richness and evenness in most of the pine-dominated stands. Lastly, our results suggest a rather straightforward application of vegetation-pollen relationships from moss/topsoil samples to interpret pollen assemblages from lakes in Mediterranean settings.

scholarly journals Indirect drivers of plant diversity-productivity relationship in semiarid sandy grasslands

2012 ◽  
Vol 9 (4) ◽  
pp. 1277-1289 ◽  
Author(s):  
X. A. Zuo ◽  
J. M. H. Knops ◽  
X. Y. Zhao ◽  
H. L. Zhao ◽  
T. H. Zhang ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Plant Diversity ◽  
Structural Equation ◽  
Environmental Gradients ◽  
Northern China ◽  
Equation Modeling ◽  
Vegetation Composition ◽  
Wet Meadow ◽  
Positive Correlation ◽  
Sandy Grasslands

Abstract. Although patterns between plant diversity and ecosystem productivity have been much studied, a consistent relationship has not yet emerged. Differing patterns between plant diversity and productivity have been observed in response to spatial variability of environmental factors and vegetation composition. In this study, we measured vegetation cover, plant diversity, productivity, soil properties and site characteristics along an environmental gradient (mobile dune, semi-fixed dune, fixed dune, dry meadow, wet meadow and flood plain grasslands) of natural sandy grasslands in semiarid areas of northern China. We used multivariate analysis to examine the relationships between environmental factors, vegetation composition, plant diversity and productivity. We found a positive correlation between plant diversity and productivity. Vegetation composition aggregated by the ordination technique of non-metric multidimensional scaling had also a significantly positive correlation with plant diversity and productivity. Environmental gradients in relation to soil and topography affected the distribution patterns of vegetation composition, species diversity and productivity. However, environmental gradients were a better determinant of vegetation composition and productivity than of plant diversity. Structural equation modeling suggested that environmental factors determine vegetation composition, which in turn independently drives both plant diversity and productivity. Thus, the positive correlation between plant diversity and productivity is indirectly driven by vegetation composition, which is determined by environmental gradients in soil and topography.

Temperate Deciduous Forests

Ecology ◽  
2012 ◽  
Author(s):  
Frank S. Gilliam
Keyword(s):  
Tropical Forests ◽  
Plant Diversity ◽  
Net Primary Productivity ◽  
Deciduous Forest ◽  
Close Association ◽  
Deciduous Forests ◽  
Human Populations ◽  
Temperate Deciduous Forest ◽  
Temperate Deciduous ◽  
Temperate Deciduous Forests

Given the global distribution of human populations and their coincidence with temperate deciduous forests, it is likely that when most people consider the term “forest,” what comes to mind most frequently is the temperate deciduous forest biome. Although not to the level of their tropical counterparts, temperate deciduous forests typically display high plant biodiversity and rates of net primary productivity. They contrast sharply, however, with tropical forests in the distribution of biodiversity and productivity. In tropical forests, greatest plant diversity is associated with the vegetation of greatest productivity—trees. By contrast, the greatest plant diversity—up to 90 percent—in temperate deciduous forests occurs among the plants of least physical stature: the herbaceous species. Given the close association between these forests and their use by human populations, whether for food, fiber, habitat, or recreation, it is not surprising that they have been well studied, particularly in North America, and thus have a rich literature going back many years. However, for the very reason of that intensive use, temperate deciduous forests have proved to be an ecological moving target, as timber harvesting, air pollution, and introduced pests (e.g., insects and parasites) have represented a chronic assault on the structure and function of these ecosystems.

Pollen and Radiolarian Records from Deep-Sea Core RC14-103: Climatic Reconstructions of Northeast Japan and Northwest Pacific for the Last 90,000 Years

1985 ◽  
Vol 24 (1) ◽  
pp. 60-72 ◽  
Author(s):  
Linda E. Heusser ◽  
Joseph J. Morley
Keyword(s):  
Deciduous Forest ◽  
Northwest Pacific ◽  
Mean Annual Temperature ◽  
Modern Pollen ◽  
Temperature And Precipitation ◽  
Glacial Environments ◽  
Summer Temperatures ◽  
Broadleaf Deciduous Forest ◽  
Northeast Asian ◽  
High Degree

Using modern pollen and radiolarian distributions in sediments from the northwest Pacific and seas adjacent to Japan to interpret floral and faunal changes in core RC14-103 (44°02′N, 152°56′E), we recognize two major responses of the biota of eastern Hokkaido and the northwest Pacific to climatic changes since the last interglaciation. Relatively stable glacial environments (∼80,000–20,000 yr B.P.) were basically cold and wet (<4°C and ∼1000 mm mean annual temperature and precipitation, respectively) with boreal conijers and tundra/park-tundra on Hokkaido, and cool (<16°C) summer and cold (<1.0°C) winter surface temperatures offshore. Contrasting nonglacial environments (∼10,000–4000 yr B.P.) were warm and humid (>8°C and >1200 mm mean annual temperature and precipitation, respectively), supporting climax broadleaf deciduous forest with Quercus and Ulmus/Zelkova, with surface waters in the northwest Pacific characterized by warm (>1.5°C) winter and cold (10.4°–14.3°C) summer temperatures. Climatic evidence from RC14-103 shows a high degree of local and regional variation within the context of global climatic change. Correlative ocean and land records provide the detailed input necessary to assess local/regional responses to variations in other key elements (i.e., solar radiation, monsoonal variations) of the northeast Asian climate system.

Plant diversity in a managed temperate deciduous forest: understorey response to two silvicultural systems

2004 ◽  
Vol 41 (6) ◽  
pp. 1065-1079 ◽  
Author(s):  
GUILLAUME DECOCQ ◽  
MICHAËL AUBERT ◽  
FREDERIC DUPONT ◽  
DIDIER ALARD ◽  
ROBERT SAGUEZ ◽  
...  
Keyword(s):  
Plant Diversity ◽  
Deciduous Forest ◽  
Temperate Deciduous Forest ◽  
Temperate Deciduous ◽  
Forest Understorey

scholarly journals How to design optimal eDNA sampling strategies for biomonitoring in river networks

2020 ◽  
Author(s):  
Luca Carraro ◽  
Julian B. Stauffer ◽  
Florian Altermatt
Keyword(s):  
Measurement Errors ◽  
Best Practice ◽  
Transport Model ◽  
Sampling Site ◽  
River Network ◽  
Decay Rates ◽  
River Networks ◽  
Sampling Effort ◽  
Biodiversity Crisis ◽  
Model Predictions

AbstractThe current biodiversity crisis calls for appropriate and timely methods to assess state and change of bio-diversity. In this respect, environmental DNA (eDNA) is a highly promising tool, especially for aquatic ecosystems. While initial eDNA studies assessed biodiversity at a few sites, technology now allows analyses of samples from many points at a time. However, the selection of these sites has been mostly motivated on an ad-hoc basis, and it is unclear where to position sampling sites in a river network to most effectively sample biodiversity. To this end, hydrology-based models might offer a unique guidance on where to sample eDNA to reconstruct the spatial patterns of taxon density based on eDNA data collected across a watershed.Here, we performed computer simulations to identify best-practice criteria for the choice of positioning of eDNA sampling sites in river networks. To do so, we combined a hydrology-based eDNA transport model with a virtual river network reproducing the scaling features of real rivers. In particular, we conducted simulations investigating scenarios of different number and location of eDNA sampling sites in a riverine network, different spatial taxon distributions, and different eDNA measurement errors.We identified best practices for sampling site selection for taxa that have a scattered versus an even distribution across the network. We observed that, due to hydrological controls, non-uniform patterns of eDNA concentration arise even if the taxon distribution is uniform and decay is neglected. We also found that uncertainties in eDNA concentration estimates do not necessarily hamper model predictions. Knowledge of eDNA decay rates improves model predictions, highlighting the need for empirical estimates of these rates under relevant environmental conditions. Our simulations help define strategies for the design of eDNA sampling campaigns in river networks, and can guide the sampling effort of field ecologists and environmental authorities.

scholarly journals The modern pollen–vegetation relationship in Jammu, India: a comparative appraisal

2021 ◽  
Vol 61 (1) ◽  
pp. 1-19
Author(s):  
Md. Firoze Quamar ◽  
Pooja Tiwari ◽  
Biswajeet Thakur
Keyword(s):  
Deciduous Forest ◽  
Principal Component ◽  
Pollination Syndrome ◽  
Fossil Pollen ◽  
Pollen Assemblage ◽  
Long Distance ◽  
Modern Pollen ◽  
Long Distance Transport ◽  
High Production ◽  
Pollen Records

An understanding of the relationship between modern pollen and vegetation is a prerequisite for reconstruction of vegetation and climate change from fossil pollen records. We conducted palynological studies of thirty-five surface soil samples from the Jammu region of India, which revealed that Pinus, among the conifers (regional needle-leaved taxa), is over-represented in the pollen assemblage due to its high production and effective dispersal of pollen. Other coniferous and broadleaved (regional and/or extra-regional) taxa have comparatively lower values in the pollen assemblages, similar to the representation of subtropical deciduous forest elements (regional), as well as shrubby (regional and/or extra-regional) taxa. This inconsistency in the pollen assemblage could be due to long-distance transport of the former by wind and/or water from the higher reaches of the Himalayas, and also because the latter have an entomogamous pollination syndrome and are not high pollen producers. The recovered pollen assemblage presents a distorted picture of the extant vegetation; hence, caution should be exercised in interpreting fossil pollen records from the study area. Principal component analysis (PCA) shows variability in the distribution of pollen from different sites in the Jammu region, perhaps the result of transport (by wind and/ or water), altitude and/or edaphic factors of the Himalayan terrain. The study should improve our understanding of the modern pollen-vegetation relationship and aid further calibration and interpretation of fossil pollen records.

Density Trends and Range Boundary Constraints of Forest Birds Along a Latitudinal Gradient

The Auk ◽  
1986 ◽  
Vol 103 (4) ◽  
pp. 791-803 ◽  
Author(s):  
John T. Emlen ◽  
Michael J. DeJong ◽  
Michael John Jaeger ◽  
Timothy C. Moermond ◽  
Kurt A. Rusterholz ◽  
...  
Keyword(s):  
Habitat Structure ◽  
Deciduous Forest ◽  
Climatic Factors ◽  
Environmental Gradients ◽  
Species Abundance ◽  
Bird Species ◽  
Population Data ◽  
Day Length ◽  
Latitudinal Gradients ◽  
Habitat Factors

Abstract We plotted the density distributions of 41 land-bird species along a 1,200-km transect spanning 7°28′ (865 km) of latitude through relatively uniform bottomland deciduous forest in middle North America. Standardized counts and observations at 12 survey stations, closely matched in habitat structure and widely distributed along the route, provided population data for all species and indices of total avian foraging pressure (consuming biomass) on each of six major foraging substrates. Density curves for species fluctuated considerably from station to station but tended to be level across range centers and slope peripherally to north and south boundaries at rates of 3-30% per degree of latitude. Substrate foraging pressures declined northward on the aerial and midfoliage substrates and southward on the low-foliage substrate. Summed community densities showed no significant latitudinal trends. We used the distinctive distribution patterns of climate (smooth latitudinal gradients), habitat structure (irregular mosaics of vegetation patches), and competition (reciprocally sloping density gradients) to identify and evaluate the role of these three constraints along the transect. Progressive latitudinal trends in species abundance thus were attributed to climatic factors, irregular station-to-station fluctuations to habitat factors, and inversely sloping density trends in paired profiles to competition. On this basis all species apparently responded to both climatic and habitat factors, and about half of the species showed suggestions of competition. In a correlation analysis across the 12 stations, latitude per se most closely matched density distribution in 12 species, one or another of the habitat parameters in 25 species. We proposed that season length (days available for breeding activity) was the principal constraining attribute of latitude at northern range boundaries, day length (hours available for feeding and provisioning young) at southern boundaries. Boundaries have been essentially stable during the past 50-100 yr in most species, but the northern boundary expanded northward in one species following human-induced habitat enhancement, and temporarily receded southward in another following a winter of severe stress. We attribute this general stability of range boundaries over time to within-population gene flow and the associated peripherally declining mean fitness of phenotypes adapted to central range conditions along radially diverging environmental gradients. We suggest that two boundary lines should be recognized for each species, an inner functional boundary at the line where birth rates drop below death rates, and an outer empirical boundary at the limit of recorded occurrences.

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