Biogeographical variation in the distribution, abundance, and interactions among key species on rocky reefs of the northeast Pacific

2020 ◽  
Vol 648 ◽  
pp. 51-65 ◽  
Author(s):  
RS Jenkinson ◽  
KA Hovel ◽  
RP Dunn ◽  
MS Edwards
Keyword(s):  
Community Structure ◽  
Trophic Interactions ◽  
Spatial Scales ◽  
Survival Rates ◽  
Local Scale ◽  
Latitudinal Gradients ◽  
Top Down ◽  
Northeast Pacific ◽  
Rocky Reefs ◽  
Key Species

Macroecological research over large latitudinal gradients can reveal broad-scale patterns that provide context for local-scale studies and insight into relevant scales of variation in community structure. Grazing by sea urchins is one of numerous physical and biotic factors that leads to geographic variation in community structure on rocky reefs worldwide. We describe patterns of abundance, distribution, and trophic interactions of urchins and their predators on subtidal rocky reefs across much of their range in the northeast Pacific Ocean. Surveys and tethering experiments were conducted between Point Conception, California, USA, and Bahía Asunción, Baja California Sur, México, including both fished areas and marine protected areas (MPAs). Variability in abundance was greatest at the smallest spatial scales (transects and sites) rather than the largest spatial scale (regions); however, we found correlative evidence of region-wide top-down control in which higher densities of predators (primarily spiny lobsters) led to increased abundances of kelp Macrocystis pyrifera. Similarly, urchin survival varied regionally, with survival rates increasing from south to north. The effect of MPAs was less clear: species abundances varied between individual MPAs, but there were no clear differences in urchin survival between MPAs and fished areas. Community structure of rocky reefs in this region varies substantially among sites and appears to be driven in some locations by predators and in others by factors that obscure the importance of trophic interactions. Our study provides empirical evidence of the variability in top-down forcing in these communities and cautions against making broad generalizations based on inferences from local-scale studies.

scholarly journals On observational and modelling strategies targeted at regional carbon exchange over continents

2009 ◽  
Vol 6 (1) ◽  
pp. 1317-1343 ◽  
Author(s):  
C. Gerbig ◽  
A. J. Dolman ◽  
M. Heimann
Keyword(s):  
Spatial Scales ◽  
Regional Scale ◽  
Local Scale ◽  
Anthropogenic Sources ◽  
Carbon Exchange ◽  
Top Down ◽  
Bottom Up ◽  
Modelling Strategies ◽  
The Impact ◽  
Up Scaling

Abstract. Estimating carbon exchange at regional scales is paramount to understanding feedbacks between climate and the carbon cycle, but also to verifying climate change mitigation such as emission reductions and strategies compensating for emissions such as carbon sequestration. This paper discusses evidence for a number of important shortcomings of current generation modelling frameworks designed to provide regional scale budgets. Current top-down and bottom-up approaches targeted at deriving consistent regional scale carbon exchange estimates for biospheric and anthropogenic sources and sinks are hampered by a number of issues: We show that top-down constraints using point measurements made from tall towers, although sensitive to larger spatial scales, are however influenced by local areas much stronger than previously thought. On the other hand, classical bottom-up approaches using process information collected at the local scale, such as from eddy covariance data, need up-scaling and validation on larger scales. We therefore argue for a combination of both approaches, implicitly providing the important local scale information for the top-down constraint, and providing the atmospheric constraint for up-scaling of flux measurements. Combining these data streams necessitates quantifying their respective representation errors, which are discussed. The impact of these findings on future network design is highlighted, and some recommendations are given.

scholarly journals On observational and modelling strategies targeted at regional carbon exchange over continents

2009 ◽  
Vol 6 (10) ◽  
pp. 1949-1959 ◽  
Author(s):  
C. Gerbig ◽  
A. J. Dolman ◽  
M. Heimann
Keyword(s):  
Spatial Scales ◽  
Regional Scale ◽  
Local Scale ◽  
Anthropogenic Sources ◽  
Carbon Exchange ◽  
Top Down ◽  
Bottom Up ◽  
Modelling Strategies ◽  
The Impact ◽  
Up Scaling

Abstract. Estimating carbon exchange at regional scales is paramount to understanding feedbacks between climate and the carbon cycle, but also to verifying climate change mitigation such as emission reductions and strategies compensating for emissions such as carbon sequestration. This paper discusses evidence for a number of important shortcomings of current generation modelling frameworks designed to provide regional scale budgets from atmospheric observations. Current top-down and bottom-up approaches targeted at deriving consistent regional scale carbon exchange estimates for biospheric and anthropogenic sources and sinks are hampered by a number of issues: we show that top-down constraints using point measurements made from tall towers, although sensitive to larger spatial scales, are however influenced by local areas much more strongly than previously thought. On the other hand, classical bottom-up approaches using process information collected at the local scale, such as from eddy covariance data, need up-scaling and validation on larger scales. We therefore argue for a combination of both approaches, implicitly providing the important local scale information for the top-down constraint, and providing the atmospheric constraint for up-scaling of flux measurements. Combining these data streams necessitates quantifying their respective representation errors, which are discussed. The impact of these findings on future network design is highlighted, and some recommendations are given.

scholarly journals Linking spatial patterns of terrestrial herbivore community structure to trophic interactions

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Jakub Witold Bubnicki ◽  
Marcin Churski ◽  
Krzysztof Schmidt ◽  
Tom A Diserens ◽  
Dries PJ Kuijper
Keyword(s):  
Spatial Distribution ◽  
Community Structure ◽  
Spatial Variation ◽  
Spatial Scales ◽  
Landscape Scale ◽  
Top Down ◽  
Large Herbivores ◽  
Bottom Up ◽  
Vegetation Heterogeneity ◽  
Herbivore Community

Large herbivores influence ecosystem functioning via their effects on vegetation at different spatial scales. It is often overlooked that the spatial distribution of large herbivores results from their responses to interacting top-down and bottom-up ecological gradients that create landscape-scale variation in the structure of the entire community. We studied the complexity of these cascading interactions using high-resolution camera trapping and remote sensing data in the best-preserved European lowland forest, Białowieża Forest, Poland. We showed that the variation in spatial distribution of an entire community of large herbivores is explained by species-specific responses to both environmental bottom-up and biotic top-down factors in combination with human-induced (cascading) effects. We decomposed the spatial variation in herbivore community structure and identified functionally distinct landscape-scale herbivory regimes (‘herbiscapes’), which are predicted to occur in a variety of ecosystems and could be an important mechanism creating spatial variation in herbivory maintaining vegetation heterogeneity.

scholarly journals Selection of Calf Bedding Sites by Female Elk in the Central Appalachian Mountains

2019 ◽  
Vol 10 (1) ◽  
pp. 91-101
Author(s):  
Joseph E. Duchamp ◽  
Melia T. DeVivo ◽  
Jon M. DeBerti ◽  
Lindsey M. Heffernan ◽  
Jason D. Kougher ◽  
...  
Keyword(s):  
Habitat Management ◽  
Spatial Scales ◽  
Survival Rates ◽  
Coniferous Forest ◽  
Appalachian Mountains ◽  
Landscape Scale ◽  
Local Scale ◽  
High Survival ◽  
Limited Information ◽  
Lactating Females

Abstract Across eastern North America, Rocky Mountain elk Cervus canadensis nelsoni have been reintroduced to 11 states and provinces that were previously occupied by the extinct eastern elk C. canadensis canadensis. Outside of Kentucky, these elk reintroductions have resulted in small populations, typically numbering fewer than 1,000 elk per state. Limited information is available about the demographics and habitat selection within these small eastern populations. The availability of high-quality habitat during the first weeks of life is important for promoting annual recruitment and the identification of these characteristics should aid in management efforts. We characterized habitat at two spatial scales surrounding the bedding sites of 83 elk calves (≤ 7 d old) in the Pennsylvania Elk Management Area during the annual calving seasons of 2005–2008. A concurrent study found that calves in this area experienced high survival (92%) during the first 4 mo of life, despite occupying an area with high predator densities. At a local scale, bedding sites used by calves were closer to ecotones, had less leaf litter, and had greater density of vegetation below 1 m compared to random sites (n = 82). At a landscape scale, calf habitat surrounding bedding sites had greater density of edges between forest and open vegetation and less coniferous forest compared to random areas. The selected habitats appear to balance the high energetic needs of lactating females at the landscape scale and the need for cover to conceal calves and reduce predation risk at a local scale. Conclusions drawn from our models suggest future habitat management include enhancements of transitional vegetation along ecotones between forest and herbaceous openings that address the needs of both lactating females and recently born calves. We recommend that managers periodically evaluate the availability of calf habitat and calf survival rates. These monitoring activities will provide insight necessary to adaptively manage elk and the habitats driving their population growth to maintain their viability in the central Appalachian Mountains.

scholarly journals Archaeal ammonia oxidizers respond to soil factors at smaller spatial scales than the overall archaeal community does in a high Arctic polar oasis

2016 ◽  
Vol 62 (6) ◽  
pp. 485-491 ◽  
Author(s):  
Samiran Banerjee ◽  
Nabla Kennedy ◽  
Alan E. Richardson ◽  
Keith N. Egger ◽  
Steven D. Siciliano
Keyword(s):  
Community Structure ◽  
Spatial Scales ◽  
Archaeal Community ◽  
Diversity Indices ◽  
High Arctic ◽  
Total Carbon ◽  
Spatial Dependency ◽  
Edaphic Factors ◽  
Total Carbon Content ◽  
Arctic Soils

Archaea are ubiquitous and highly abundant in Arctic soils. Because of their oligotrophic nature, archaea play an important role in biogeochemical processes in nutrient-limited Arctic soils. With the existing knowledge of high archaeal abundance and functional potential in Arctic soils, this study employed terminal restriction fragment length polymorphism (t-RFLP) profiling and geostatistical analysis to explore spatial dependency and edaphic determinants of the overall archaeal (ARC) and ammonia-oxidizing archaeal (AOA) communities in a high Arctic polar oasis soil. ARC communities were spatially dependent at the 2–5 m scale (P < 0.05), whereas AOA communities were dependent at the ∼1 m scale (P < 0.0001). Soil moisture, pH, and total carbon content were key edaphic factors driving both the ARC and AOA community structure. However, AOA evenness had simultaneous correlations with dissolved organic nitrogen and mineral nitrogen, indicating a possible niche differentiation for AOA in which dry mineral and wet organic soil microsites support different AOA genotypes. Richness, evenness, and diversity indices of both ARC and AOA communities showed high spatial dependency along the landscape and resembled scaling of edaphic factors. The spatial link between archaeal community structure and soil resources found in this study has implications for predictive understanding of archaea-driven processes in polar oases.

Spatial covariation in survival rates of Northeast Pacific pink salmon (Oncorhynchus gorbuscha)

2001 ◽  
Vol 58 (8) ◽  
pp. 1501-1515 ◽  
Author(s):  
Brian J Pyper ◽  
Franz J Mueter ◽  
Randall M Peterman ◽  
David J Blackbourn ◽  
Chris C Wood
Keyword(s):  
Spatial Scales ◽  
Pink Salmon ◽  
Survival Rates ◽  
Ocean Basin ◽  
Oncorhynchus Gorbuscha ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Geographical Regions ◽  
Basin Scale ◽  
Stock Recruitment ◽  
Best Fit

We examined spatial patterns of covariation in indices of survival rate (residuals from the best-fit stock- recruitment curve) across four decades among 43 wild pink salmon (Oncorhynchus gorbuscha) stocks from 14 geographical regions in Washington, British Columbia, and Alaska. We found strong evidence of positive covariation among stocks within each region and between certain adjacent regions (e.g., correlations from 0.3 to 0.7) but no evidence of covariation between stocks of distant regions (e.g., separated by 1000 km or more). This suggests that important environmental processes affecting temporal variation in survival rates of pink salmon from spawners to recruits operate at regional spatial scales rather than at the larger ocean basin scale. Based on limited fry abundance data, we found that this covariation in spawner-to-recruit survival rates may be strongly influenced by marine processes.

scholarly journals Interhemispheric consistency of scale-dependent spatial variation in the structure of intertidal rocky-shore communities

2018 ◽  
Author(s):  
Alexis Catalán ◽  
Nelson Valdivia ◽  
Ricardo Scrosati
Keyword(s):  
Community Structure ◽  
Spatial Variation ◽  
Spatial Scales ◽  
Vertical Gradient ◽  
Sampling Interval ◽  
Biological Variation ◽  
Rocky Intertidal ◽  
Vertical Variation ◽  
Horizontal Variation ◽  
Sampling Intervals

In rocky intertidal environments, the vertical gradient of abiotic stress generates, directly or indirectly, significant spatial variation in community structure. Along shorelines within biogeographic regions, abiotic changes also generate horizontal biological variation, which when measured at large sampling intervals may surpass vertical biological variation. Little is known, however, on how vertical variation compares with horizontal variation measured at multiple spatial scales in habitats with similar environmental conditions. Here, we compare spatial variability in rocky-intertidal communities between vertical stress gradients and three horizontal spatial scales (sampling interval) across habitats experiencing the same wave exposure on the Northwest Atlantic (NWA) and Southeast Pacific (SEP) coasts. For both regions, the vertical variation in species richness and composition (Raup-Crick and Bray-Curtis indices) was higher than the variation measured at all horizontal scales, from a few cm to hundreds of km. The patterns of variation in community structure matched those of abundance for the dominant sessile organisms, the foundation species Ascophyllum nodosum (seaweed) in NWA and Perumytilus purpuratus (mussel) in SEP. This interhemispheric comparison reveals the tight link between environmental and biological variation, indicating that studies comparing spatial scales of biological variation must consider the underlying environmental variation in addition to simply scale alone.

scholarly journals Interhemispheric consistency of scale-dependent spatial variation in the structure of intertidal rocky-shore communities

2018 ◽  
Author(s):  
Alexis Catalán ◽  
Nelson Valdivia ◽  
Ricardo Scrosati
Keyword(s):  
Community Structure ◽  
Spatial Variation ◽  
Spatial Scales ◽  
Vertical Gradient ◽  
Sampling Interval ◽  
Biological Variation ◽  
Rocky Intertidal ◽  
Vertical Variation ◽  
Horizontal Variation ◽  
Sampling Intervals

In rocky intertidal environments, the vertical gradient of abiotic stress generates, directly or indirectly, significant spatial variation in community structure. Along shorelines within biogeographic regions, abiotic changes also generate horizontal biological variation, which when measured at large sampling intervals may surpass vertical biological variation. Little is known, however, on how vertical variation compares with horizontal variation measured at multiple spatial scales in habitats with similar environmental conditions. Here, we compare spatial variability in rocky-intertidal communities between vertical stress gradients and three horizontal spatial scales (sampling interval) across habitats experiencing the same wave exposure on the Northwest Atlantic (NWA) and Southeast Pacific (SEP) coasts. For both regions, the vertical variation in species richness and composition (Raup-Crick and Bray-Curtis indices) was higher than the variation measured at all horizontal scales, from a few cm to hundreds of km. The patterns of variation in community structure matched those of abundance for the dominant sessile organisms, the foundation species Ascophyllum nodosum (seaweed) in NWA and Perumytilus purpuratus (mussel) in SEP. This interhemispheric comparison reveals the tight link between environmental and biological variation, indicating that studies comparing spatial scales of biological variation must consider the underlying environmental variation in addition to simply scale alone.

scholarly journals Spatial analysis of phylogenetic community structure: New version of a classical method

2015 ◽  
Author(s):  
Carlo Ricotta ◽  
Eszter EA Ari ◽  
Giuliano Bonanomi ◽  
Francesco Giannino ◽  
Duncan Heathfield ◽  
...  
Keyword(s):  
Community Structure ◽  
Spatial Scales ◽  
Point Pattern ◽  
Maximum Deviation ◽  
Individual Plant ◽  
Phylogenetic Distance ◽  
Phylogenetic Structure ◽  
Phylogenetic Community Structure ◽  
Point Patterns ◽  
Wide Range

The increasing availability of phylogenetic information facilitates the use of evolutionary methods in community ecology to reveal the importance of evolution in the species assembly process. However, while several methods have been applied to a wide range of communities across different spatial scales with the purpose of detecting non-random phylogenetic patterns, the spatial aspects of phylogenetic community structure have received far less attention. Accordingly, the question for this study is: can point pattern analysis be used for revealing the phylogenetic structure of multi-species assemblages? We introduce a new individual-centered procedure for analyzing the scale-dependent phylogenetic structure of multi-species point patterns based on digitized field data. The method uses nested circular plots with increasing radii drawn around each individual plant and calculates the mean phylogenetic distance between the focal individual and all individuals located in the circular ring delimited by two successive radii. This scale-dependent value is then averaged over all individuals of the same species and the observed mean is compared to a null expectation with permutation procedures. The method detects particular radius values at which the point pattern of a single species exhibits maximum deviation from the expectation towards either phylogenetic aggregation or segregation. Its performance is illustrated using data from a grassland community in Hungary and simulated point patterns. The proposed method can be extended to virtually any distance function for species pairs, such as functional distances.

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