The Experts below are selected from a list of 9594 Experts worldwide ranked by ideXlab platform
R S K Barnes - One of the best experts on this subject based on the ideXlab platform.
-
do species display characteristic intraspecific levels of Patchiness in a given habitat type the case of intertidal seagrass macrobenthos
Marine Biology, 2020Co-Authors: R S K BarnesAbstract:Intertidal macrobenthic assemblages associated with monospecific stands of Zostera muelleri, Cymodocea serratula, Halodule uninervis and Halophila ovalis seagrasses are known to display uniform spatial Patchiness on the Moreton Bay coast of North Stradbroke Island, Queensland, as do those in Z. capensis in the Knysna estuarine bay, South Africa. Thirty-seven historical datasets of these macrobenthic assemblages were re-analysed to assess variation of local Patchiness in each of the 18 most common individual assemblage components at each of these localities in terms of three metrics: overall Patchiness (Lloyd's index of Patchiness), levels of unoccupancy, and variation in abundance across occupied samples (Lloyd's index of mean crowding). Within-site Patchiness was not caused by a restriction of individual species to specific subareas but by variation in their local density, particularly by the extent of unoccupied ‘interstitial’ spaces within patches. Especially in the more uniform Queensland conditions, the more common species occurred relatively widely across the whole locality; individual samples from which a given species was absent never themselves formed patches, the number of such samples conforming to points on truncated normal curves of the frequency of occurrence. Of the 36 species investigated, the two most abundant and widespread both in Queensland and in South Africa displayed significant or near-significant uniformity of levels of local Patchiness, whilst five showed significantly uniform mean crowding and ten significantly uniform unoccupancy. This is the first demonstration that some species may display a characteristic level of Patchiness in a given habitat type.
-
abundance occupancy Patchiness relations in estuarine seagrass macrobenthos
Estuarine Coastal and Shelf Science, 2019Co-Authors: R S K BarnesAbstract:Abstract Using >1800 macrobenthic samples from 25 representative intertidal seagrass sites in the Knysna estuarine bay (warm-temperate South Africa), abundance/occupancy relations were examined in the light of Foggo et al.'s (2003) earlier work concerning British estuarine faunas. In addition, the relationship of degree of variation in macrobenthic abundance across unit area, 'Patchiness', to this macroecological picture was investigated. Across the group of 30 dominant faunal components as a whole, the most widely and abundantly distributed species had (a) the highest mean abundances and (b) the least spatially-patchy densities in each of Knysna's diverse regions and at all spatial scales from landscape to local; however no significant relationship was observed between mean abundance and degree of Patchiness. Individual dominant species displayed considerable variation; some showing positive occupancy/Patchiness correlations, and several displaying significant positive and others negative abundance/Patchiness ones. As expected along the estuarine gradient, positive and negative correlations of both abundance and occupancy with distance upstream were found in different species (both metrics in a given species always responding in the same manner), although significant upstream relationships with Patchiness were found in only two. Local Patchiness clearly contributes macroecological information additional to that provided by abundance or occupancy.
-
isometric scaling of faunal Patchiness seagrass macrobenthic abundance across small spatial scales
Marine Environmental Research, 2019Co-Authors: R S K Barnes, Sarah HamyltonAbstract:Abstract Following earlier studies across 2115 → 33 m2 scales (Barnes and Laurie, 2018), Patchiness of macrobenthic abundance in intertidal Queensland seagrass was assessed by dispersion indices, spatial autocorrelation and hotspot analysis across a hierarchically-nested series of smaller scales (5.75 → 0.09 m2). Overall patterns of distribution and abundance over larger extents and with greater lag were mirrored across these smaller ones. Assemblage abundance per station varied by a factor of >10, but all three approaches showed effective constancy of total assemblage Patchiness across all sub-2115 m2 scales (across-scales-mean Lloyd's IP of 1.06 and global Moran's I of 0.13). Equivalent constancy was also shown by most numerically-dominant species (scaling exponent β = 0.93–1.15). Decreasing Patchiness of some species with decreasing scale, however, resulted in two no longer being patchily dispersed across small scales. Significant hotspots of abundance occurred at a constant proportion of stations across scales, against a background of randomly scattered peak-abundance points.
Zhiwei Wang - One of the best experts on this subject based on the ideXlab platform.
-
effect of plateau pika disturbance and Patchiness on ecosystem carbon emissions in alpine meadow in the northeastern part of qinghai tibetan plateau
Biogeosciences, 2019Co-Authors: Yu Qin, Yongjian Ding, Jianjun Chen, Wei Zhang, Yan Qin, Zhiwei WangAbstract:Abstract. Plateau pika (Ochotona curzoniae) disturbance and Patchiness intensify the spatial heterogeneous distribution of vegetation productivity and soil physicochemical properties, which may alter the ecosystem carbon emission process. Nevertheless, previous research has mostly focused on the homogeneous vegetation patches rather than heterogeneous land surface. Thus, this study aims to improve our understanding of the difference in ecosystem respiration (Re) over heterogeneous land surface in an alpine meadow grassland. Six different land surface types, namely large bald patches, medium bald patches, small bald patches, intact grassland, above pika tunnel and pika pile, were selected to analyze the response of Re to pika disturbance and Patchiness and the key controlling factors. The results showed that (1) Re in intact grassland was 0.22–1.07 times higher than pika pile and bald patches, (2) soil moisture (SM) of intact grassland was 2 %–11 % higher than that of pika pile and bald patches, despite the fact that pika disturbance increased the water infiltration rate while soil temperature (ST) in intact grassland was 1–3 ∘ less than pika pile and bald patches, (3) soil organic carbon (SOC) and total nitrogen (TN) in intact grassland were approximately 50 % and 60 % less than above pika tunnel, whereas they were 10 %–30 % and 22 %–110 % higher than pika pile and bald patches, and (4) Re was significantly correlated with SM, TN and vegetation biomass ( P ). Our results suggested that pika disturbance and Patchiness altered the ecosystem carbon emission pattern, which was mainly attributed to the reduction in soil water and supply of substrates. Given the wide distribution of pikas and the large area of bald patches, the varied Re in heterogeneous land surfaces should not be neglected in the estimation of ecosystem carbon emissions at the plot or regional scale.
-
effects of small scale Patchiness of alpine grassland on ecosystem carbon and nitrogen accumulation and estimation in northeastern qinghai tibetan plateau
Geoderma, 2018Co-Authors: Yu Qin, Yongjian Ding, Jianjun Chen, Zhiwei WangAbstract:Abstract Small-scale Patchiness intensified the spatial heterogeneous distribution of soil and vegetation organic carbon (C) and total nitrogen (N), thereby inducing large uncertainty in estimating ecosystem C and N stocks. However, Patchiness at this scale was difficult to identify by satellite remote sensing and measure in situ. Aerial photographing can provide high-precision images and can potentially improve estimating accuracy in ecosystem C and N stocks. In this study, using combined methods of field sampling, aerial photographing and satellite images, we investigated the characteristics of Patchiness, quantified ecosystem C and N stocks in different patches at plot scale (~ 1000 m2) and eventually estimated the uncertainty in ecosystem C and N stocks caused by small-scale Patchiness at basin scale. Results showed that: 1) mosaic of vegetation and bald patches coexisted for swamp meadow and alpine meadow, whereas vegetation presented as spot for steppe meadow and alpine steppe; 2) average ecosystem respiration, C and N stocks in intact grassland patches were 2.05 and 1.65, 1.66 and 1.65, 2.01 and 1.69 times higher than those of large and medium bare patches (P
Daniel D Heath - One of the best experts on this subject based on the ideXlab platform.
-
kin aggregations explain chaotic genetic Patchiness a commonly observed genetic pattern in a marine fish
PLOS ONE, 2016Co-Authors: Jason D Selwyn, Derek J Hogan, Alan M Downeywall, Lauren M Gurski, David S Portnoy, Daniel D HeathAbstract:The phenomenon of chaotic genetic Patchiness is a pattern commonly seen in marine organisms, particularly those with demersal adults and pelagic larvae. This pattern is usually associated with sweepstakes recruitment and variable reproductive success. Here we investigate the biological underpinnings of this pattern in a species of marine goby Coryphopterus personatus. We find that populations of this species show tell-tale signs of chaotic genetic Patchiness including: small, but significant, differences in genetic structure over short distances; a non-equilibrium or “chaotic” pattern of differentiation among locations in space; and within locus, within population deviations from the expectations of Hardy-Weinberg equilibrium (HWE). We show that despite having a pelagic larval stage, and a wide distribution across Caribbean coral reefs, this species forms groups of highly related individuals at small spatial scales (<10 metres). These spatially clustered family groups cause the observed deviations from HWE and local population differentiation, a finding that is rarely demonstrated, but could be more common than previously thought.
Robert J Toonen - One of the best experts on this subject based on the ideXlab platform.
-
taking the chaos out of genetic Patchiness seascape genetics reveals ecological and oceanographic drivers of genetic patterns in three temperate reef species
Molecular Ecology, 2010Co-Authors: Kimberly A Selkoe, James R Watson, Crow White, Tal Ben Horin, Matthew Iacchei, Satoshi Mitarai, David A Siegel, Steven D Gaines, Robert J ToonenAbstract:Marine species frequently show weak and ⁄or complex genetic structuring that is commonly dismissed as ‘chaotic’ genetic Patchiness and ecologically uninformative. Here, using three datasets that individually feature weak chaotic Patchiness, we demonstrate that combining inferences across species and incorporating environmental data can greatly improve the predictive value of marine population genetics studies on small spatial scales. Significant correlations in genetic patterns of microsatellite markers among three species, kelp bass Paralabrax clathratus, Kellet’s whelk Kelletia kelletii and California spiny lobster Panulirus interruptus, in the Southern California Bight suggest that slight differences in diversity and pairwise differentiation across sampling sites are not simply noise or chaotic Patchiness, but are ecologically meaningful. To test whether interspecies correlations potentially result from shared environmental drivers of genetic patterns, we assembled data on kelp bed size, sea surface temperature and estimates of site-to-site migration probability derived from a high resolution multi-year ocean circulation model. These data served as predictor variables in linear models of genetic diversity and linear mixed models of genetic differentiation that were assessed with information–theoretic model selection. Kelp was the most informative predictor of genetics for all three species, but ocean circulation also played a minor role for kelp bass. The shared patterns suggest a single spatial marine management strategy may effectively protect genetic diversity of multiple species. This study demonstrates the power of environmental and ecological data to shed light on weak genetic patterns and highlights the need for future focus on a mechanistic understanding of the links between oceanography, ecology and genetic structure.
Yu Qin - One of the best experts on this subject based on the ideXlab platform.
-
effect of plateau pika disturbance and Patchiness on ecosystem carbon emissions in alpine meadow in the northeastern part of qinghai tibetan plateau
Biogeosciences, 2019Co-Authors: Yu Qin, Yongjian Ding, Jianjun Chen, Wei Zhang, Yan Qin, Zhiwei WangAbstract:Abstract. Plateau pika (Ochotona curzoniae) disturbance and Patchiness intensify the spatial heterogeneous distribution of vegetation productivity and soil physicochemical properties, which may alter the ecosystem carbon emission process. Nevertheless, previous research has mostly focused on the homogeneous vegetation patches rather than heterogeneous land surface. Thus, this study aims to improve our understanding of the difference in ecosystem respiration (Re) over heterogeneous land surface in an alpine meadow grassland. Six different land surface types, namely large bald patches, medium bald patches, small bald patches, intact grassland, above pika tunnel and pika pile, were selected to analyze the response of Re to pika disturbance and Patchiness and the key controlling factors. The results showed that (1) Re in intact grassland was 0.22–1.07 times higher than pika pile and bald patches, (2) soil moisture (SM) of intact grassland was 2 %–11 % higher than that of pika pile and bald patches, despite the fact that pika disturbance increased the water infiltration rate while soil temperature (ST) in intact grassland was 1–3 ∘ less than pika pile and bald patches, (3) soil organic carbon (SOC) and total nitrogen (TN) in intact grassland were approximately 50 % and 60 % less than above pika tunnel, whereas they were 10 %–30 % and 22 %–110 % higher than pika pile and bald patches, and (4) Re was significantly correlated with SM, TN and vegetation biomass ( P ). Our results suggested that pika disturbance and Patchiness altered the ecosystem carbon emission pattern, which was mainly attributed to the reduction in soil water and supply of substrates. Given the wide distribution of pikas and the large area of bald patches, the varied Re in heterogeneous land surfaces should not be neglected in the estimation of ecosystem carbon emissions at the plot or regional scale.
-
effects of small scale Patchiness of alpine grassland on ecosystem carbon and nitrogen accumulation and estimation in northeastern qinghai tibetan plateau
Geoderma, 2018Co-Authors: Yu Qin, Yongjian Ding, Jianjun Chen, Zhiwei WangAbstract:Abstract Small-scale Patchiness intensified the spatial heterogeneous distribution of soil and vegetation organic carbon (C) and total nitrogen (N), thereby inducing large uncertainty in estimating ecosystem C and N stocks. However, Patchiness at this scale was difficult to identify by satellite remote sensing and measure in situ. Aerial photographing can provide high-precision images and can potentially improve estimating accuracy in ecosystem C and N stocks. In this study, using combined methods of field sampling, aerial photographing and satellite images, we investigated the characteristics of Patchiness, quantified ecosystem C and N stocks in different patches at plot scale (~ 1000 m2) and eventually estimated the uncertainty in ecosystem C and N stocks caused by small-scale Patchiness at basin scale. Results showed that: 1) mosaic of vegetation and bald patches coexisted for swamp meadow and alpine meadow, whereas vegetation presented as spot for steppe meadow and alpine steppe; 2) average ecosystem respiration, C and N stocks in intact grassland patches were 2.05 and 1.65, 1.66 and 1.65, 2.01 and 1.69 times higher than those of large and medium bare patches (P
