Distribution patterns Small-scale pattern: patchiness

2000 ◽  
pp. 225-244
Keyword(s):  
Distribution Patterns ◽  
Small Scale

Small-scale distribution and salinity response of Juniperus virginiana on an Atlantic Coast barrier island

1997 ◽  
Vol 75 (1) ◽  
pp. 77-85 ◽  
Author(s):  
David W. Martin ◽  
Donald R. Young
Keyword(s):  
Ground Water ◽  
Atlantic Coast ◽  
Barrier Island ◽  
Distribution Patterns ◽  
Small Scale ◽  
Juniperus Virginiana ◽  
Plant Responses ◽  
Rooting Zone ◽  
Red Cedar ◽  
Salinity Response

A field and laboratory study examined the hypothesis that the small-scale distribution pattern of Juniperus virginiana on barrier islands is related to salinity patterns and plant responses to salinity. Temporal (May – October) and spatial variability in ground water availability, ground water salinity, and total soil chlorides were quantified across a Virginia barrier island. Groundwater depth and salinity increased throughout the summer; microtopographic position and location on the island also affected soil salinities. Highest salinities occurred near the ocean side beach and bay side marsh, as well as in low lying swales that flood during extreme high tides or storms. Median rooting zone chloride level for J. virginiana was 54 μg/g. In contrast, laboratory germination and growth studies indicated that J. virginiana was significantly affected only at high salinity levels (1000 and 1400 μg/g), suggesting that salinity is not the only factor regulating small-scale distribution patterns. The broad tolerance to salinity may account for the abundance of J. virginiana in coastal environments. Key words: barrier island, eastern red cedar, Juniperus virginiana, salinity response, water relations.

Distribution Patterns of Escherichia coli O157:H7 in Ground Beef Produced by a Laboratory-Scale Grinder†

2002 ◽  
Vol 65 (12) ◽  
pp. 1894-1902 ◽  
Author(s):  
ROLANDO A. FLORES ◽  
MARK L. TAMPLIN
Keyword(s):  
Escherichia Coli ◽  
Ground Beef ◽  
Distribution Patterns ◽  
Small Scale ◽  
Escherichia Coli O157 ◽  
Inoculum Level ◽  
E Coli ◽  
Specific Distribution ◽  
Low Levels ◽  
G Prior

This study determined the distribution patterns of Escherichia coli O157:H7 in ground beef when a contaminated beef trim was introduced into a batch of uncontaminated beef trims prior to grinding in a small-scale laboratory grinder. A beef trim (15.3 ± 2 g) was inoculated with a rifampicin-resistant strain of E. coli O157:H7 (E. coli O157:H7rif) and introduced into a stream of noncontaminated beef (322 ± 33 g) prior to grinding. Seven inoculum levels (6, 5, and 4 total log CFU [high]; and 3, 2, 1, and 0 total log CFU [low]) were studied in triplicate. E. coli O157:H7rif was not detected in 3.1 to 43% of the ground beef inoculated with the high levels or in 3.4 to 96.9% of the ground beef inoculated with the low levels. For all inoculum levels studied, the five ground beef fractions (each 7.8 ± 0.6 g) with the highest pathogen levels accounted for 59 to 100% of the total pathogens detected. For all inoculum levels, there was a linear relationship between the quantity of ground beef containing E. coli O157:H7rif and the inoculum level. The quantity of E. coli O157:H7rif in the beef remaining in the grinder was proportional to the inoculum level and was related to the location in the grinder. Different components of the grinder accumulated E. coli O157:H7rif in different quantities, with the most significant accumulation being in the nut (collar) that attaches the die to the blade. This study determined specific distribution patterns of E. coli O157:H7rif after the grinding of a contaminated beef trim along with uncontaminated trims, and the results indicate that the grinding operation should be regarded as a means of distribution of microbial contamination in risk analyses of ground beef operations.

Spatial aggregation patterns of free-living marine nematodes in contrasting sandy beach micro-habitats

2010 ◽  
Vol 91 (3) ◽  
pp. 615-622 ◽  
Author(s):  
Ruth Gingold ◽  
Silvia E. Ibarra-Obando ◽  
Axayácatl Rocha-Olivares
Keyword(s):  
Negative Correlation ◽  
Sandy Beach ◽  
Distribution Patterns ◽  
Significant Negative Correlation ◽  
Small Scale ◽  
Spatial Distributions ◽  
Biological Processes ◽  
Marine Nematodes ◽  
Free Living ◽  
Biological Similarity

In the absence of chemical or physical gradients, random displacement of organisms can result in unpredictable distribution patterns. In spite of a limited locomotive capability, marine nematodes may choose where to settle after re-suspension and may maintain their position in the sediment under calm conditions, leading to small-scale (<1 m) spatial variability. However, in more energetic environments, nematodes become re-suspended with sediments and re-distributed at distances dependent on prevalent hydrodynamic regimes, from metre- to decametre-scale or more. In this study, we tested the hypothesis that micro-habitats (i.e. runnels and sandbars) in a macrotidal sandy beach influence the distribution patterns of free-living marine nematodes by exhibiting contrasting hydrodynamic regimes. Specifically, we predicted patchier distributions in the calmer environment (runnel). We sampled nematodes in each habitat from <1 m to decametre scales. Our results show more heterogeneous spatial distributions in the runnel, presumably owing to a predominance of active displacement under calmer conditions and sediment cohesion by algal films. Biological similarity among runnel replicates was low, whereas replicates from the sandbar exhibited higher similarity, presumably because of homogenization of the sediment and inhabiting fauna by tidal currents. A significant negative correlation between biological similarity and sampling distance was found in the runnel, but not in the sandbar. The most similar samples were the closest in the runnel and the most distant in the sandbar. More patchily distributed taxa were found in the runnel and a larger fraction of homogeneously or randomly distributed taxa in the sandbar. We conclude that different hydrodynamic regimes in contrasting intertidal micro-habitats significantly influenced the nematofaunal distribution, resulting in different spatial patterns next to one another in the same beach. This has significant implications for sampling and monitoring designs and begs the need for detailed studies about the physical and biological processes governing meiobenthic communities.

Patterns of abundance and size of Dictyoceratid sponges among neighbouring islands in central Torres Strait, Australia

2007 ◽  
Vol 58 (2) ◽  
pp. 204 ◽  
Author(s):  
Alan R. Duckworth ◽  
Carsten W. Wolff
Keyword(s):  
Spatial Scales ◽  
Distribution Patterns ◽  
Small Scale ◽  
Size Frequency Distribution ◽  
Abundance Patterns ◽  
Size Frequency ◽  
Dysidea Herbacea ◽  
Torres Strait ◽  
Study Sites ◽  
Species Specific

Distribution and size frequency patterns of sessile organisms such as sponges may vary among and within neighbouring reefs. In the present study, we examined small-scale variation of dictyoceratid sponges (class Demospongiae), commonly found on coral reefs, by surveying six neighbouring islands in central Torres Strait. Each island had four study sites, at least 1 km apart, with each site consisting of three shallow (4 to 6 m) and three deep (10 to 15 m) 20 m2 transects. For each transect, we recorded the number of each species and measured the size of the more common dictyoceratid sponges. Seven species of dictyoceratid were recorded in central Torres Strait, with only three species, Coscinoderma sp., Dysidea herbacea and Hyrtios erecta, common to all six islands. Abundance patterns generally varied greatly among islands or sites within islands, perhaps resulting from a combination of physical, biological and stochastic factors. More dictyoceratids were found in deeper water; however, abundance across depth for some species varied among islands or sites. Size-frequency distribution patterns also varied greatly among islands and dictyoceratid species, indicating that factors that may promote growth for one species may not necessarily promote growth for a related species. This study shows that patterns of abundance and size of dictyoceratids can vary greatly over small spatial scales, and that patterns are species-specific.

Cryptic species in sympatry: nonrandom small-scale distribution patterns inBostrychia intricata(Ceramiales, Rhodophyta)

Phycologia ◽  
2016 ◽  
Vol 55 (4) ◽  
pp. 424-430 ◽  
Author(s):  
Narongrit Muangmai ◽  
Ulla von Ammon ◽  
Giuseppe C. Zuccarello
Keyword(s):  
Cryptic Species ◽  
Distribution Patterns ◽  
Small Scale

Small scale distribution patterns of female and male Daubenton's bats (Myotis daubentonii)

2006 ◽  
Vol 8 (2) ◽  
pp. 403-415 ◽  
Author(s):  
Markus Dietz ◽  
Jorge A. Encarnação ◽  
Elisabeth K. V. Kalko
Keyword(s):  
Distribution Patterns ◽  
Small Scale ◽  
Myotis Daubentonii

scholarly journals Cryptic species in sympatry: Nonrandom small-scale distribution patterns in Bostrychia intricata (Ceramiales, Rhodophyta)

2020 ◽  
Author(s):  
N Muangmai ◽  
U Von Ammon ◽  
Giuseppe Zuccarello
Keyword(s):  
Cryptic Species ◽  
Algal Species ◽  
Sun Exposure ◽  
Distribution Patterns ◽  
Molecular Data ◽  
Small Scale ◽  
Ecological Resources ◽  
Intertidal Habitats ◽  
Multiple Species ◽  
Multiple Samples

© 2016 International Phycological Society. Sympatric coexistence of cryptic species, indistinguishable morphological taxa, has increasingly been detected on the basis of molecular data. This discovery raises the interesting question of how cryptic species can coexist, as hypothetically they would need identical ecological resources. The red alga Bostrychia intricata is commonly found along New Zealand shores. Previous studies indicated several cryptic species within this morphospecies, and that some populations have multiple species. This study aimed to determine how coexisting cryptic B. intricata distribute at a small scale. Along the shore of Moa Point, Wellington, we conducted intensive sampling of B. intricata in different habitats with respect to tidal position, wave and sun exposure levels. Our genetic data clearly documented the coexistence of three cryptic species of B. intricata: N2, N4 and N5. Multiple samples from individual algal patches indicated that each patch was made of the same ramet. Our analyses revealed a habitat-related pattern in small-scale distribution of different cryptic B. intricata, suggesting that the distribution of these cryptic species was not random. Cryptic species N4 was found at a higher tidal position than species N2 and N5, whereas cryptic species N2 occurred in more wave-exposed areas than the other species. Discriminant analysis indicated that tidal height strongly influenced the distribution pattern among these cryptic species. Our observations demonstrated that the co-occurrence of three cryptic B. intricata can partly be explained by their occupation of different intertidal habitats, highlighting the nonrandom distribution of coexisting cryptic algal species.

scholarly journals Adaptive diversity of beech seedlings under climate change scenarios

2018 ◽  
Author(s):  
Georgios Varsamis ◽  
Aristotelis C Papageorgiou ◽  
Theodora Merou ◽  
Ioannis Takos ◽  
Chrisovalantis Malesios ◽  
...  
Keyword(s):  
Climate Change ◽  
Seedling Survival ◽  
Temporal Distribution ◽  
Distribution Patterns ◽  
Growth Chamber ◽  
Small Scale ◽  
Climate Change Scenarios ◽  
Southeastern Part ◽  
Temperature And Precipitation ◽  
Adaptive Diversity

The ability of beech (Fagus sylvatica L.) populations to adapt to the ongoing climate change is crucial for the maintenance of economic and social benefits and for the conservation of biodiversity in Europe and especially in the southeastern part of the continent, where environmental change is expected to be more intense. Beech populations in the region cover multiple ecological conditions at a small geographical range and have a complex biogeographical background involving several postglacial lineages originating from distant or local refugia. In this study, we tested the existing adaptive potential of eight beech populations from two provenances in N.E. Greece (Evros and Drama), under simulated controlled climate change conditions in a growth chamber and in the field. In the growth chamber, simulated conditions of temperature and precipitation for the year 2050 were applied for three years, under two different irrigation schemes, a non-frequent (A1) and a frequent one (A2). Seedling survival, growth and leaf phenological traits were used as adaptive traits. The results showed that beech seedlings were generally able to survive under climate change conditions and showed adaptive differences among provenances and populations. Furthermore, beech genotypes demonstrated an impressive phenotypic plasticity by changing the duration of their growing season allowing them to avoid environmental stress and high selection pressure. Different populations and provenances were connected with different adaptation strategies, that relate mainly to the temporal distribution patterns of precipitation and temperature, rather than the average annual or monthly values of these measures. Additionally, different adaptive strategies appeared among beech seedlings when the same amount of water was distributed differently within each month. This indicates that the physiological response mechanisms of beech individuals are very complex and depend on several interacting parameters. For this reason, the choice of beech provenances for translocation and use in afforestation or reforestation projects should consider the small scale ecotypic diversity of the species and view multiple environmental and climatic parameters in connection to each other.

scholarly journals Comparison of tree diameter distributions in managed and unmanaged Kazdağı fir forests

2021 ◽  
Vol 22 (1) ◽  
pp. 31-43
Author(s):  
Ferhat Kara
Keyword(s):  
Small Diameter ◽  
Structural Complexity ◽  
Distribution Patterns ◽  
Wildlife Habitat ◽  
Diameter Distribution ◽  
Future Research ◽  
Small Scale ◽  
Tree Diameter ◽  
Diameter Structure ◽  
Unmanaged Forest

Forest structural complexity affects tree growth, species diversity, understory seedling density, wildlife habitat and fire behaviour. Thus, defining the structural complexity of forest ecosystems would play a crucial role in their management. The vertical structure in stands of shade-tolerant tree species can be described by using the distribution of tree diameters. In this study, the main objective was to determine and compare the diameter distribution patterns of managed and unmanaged Kazda&#287;&#305; fir (Abies nordmanniana subsp. equi-trojani) forests in northern Turkey. Hierarchical clustering analysis was used to define the diameter distribution patterns. Three main diameter distribution patterns were examined in both managed and unmanaged forests. Two of the patterns in the managed forest did not possess the expected diameter structure of selection silviculture (i.e. reverse J-shape). The observed patterns in the unmanaged forest were mostly representative of the diameter structure of old-growth forests. Given the initial findings, it is likely that the small-scale disturbances created by selection methods may not be adequate to establish and recruit sufficient number of trees into small- diameter sizes in Kazda&#287;&#305; fir forests. The assessment of patterns of tree diameter distribution in these forests would create a basis for future research, aiming to enhance the structural complexity.

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