Abiotic and Biotic Drivers of Spatial Variation in Salt Marsh Species Interactions and Community Dynamics

Abiotic and Biotic Drivers of Spatial Variation in Salt Marsh Species Interactions and Community Dynamics PDF Author: Akana Noto
Publisher:
ISBN:
Category :
Languages : en
Pages : 151

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Book Description
Interactions among members of ecological communities often vary spatially in response to environmental differences. Yet interactions can also vary spatially as a result of biotic factors such as differences in species traits or variation in other species interactions. It is necessary to understand the conditions under which each of these drivers of variation has an effect in order to predict how species interactions will be affected both by changes in the environment and in biotic communities. In this thesis, I explore mechanisms that may cause species interactions to vary across space at local, regional and continental scales in salt marsh plant communities. Chapter 1 investigates the relationship between the environment (means and variability) and community diversity and stability in time-series data from the east and west coasts of North America. Chapter 2 experimentally investigates the effect of sea-level rise on species interactions within a marsh. Chapter 3 seeks to understand geographic variation in plant interactions among six sites spanning the California coast. Chapter 4 uses a common garden experiment to test whether spatial variation in species interactions are driven by differences among plant populations or the environment. Finally, Chapter 5 describes geographic patterns of variation in herbivore pressure to determine whether herbivory drives regional differences in interactions among plants. I found that changes in mean conditions, including sea level, can affect community diversity, stability and strength of species interactions. Environmental variability only affects community stability and diversity when it is relatively large, so increases in variability with climate change may cause plant community dynamics to become affected by both variability and means. Species interactions vary geographically along the west coast, but unlike on the east coast, do not show consistent trends with latitude. Rather, interaction strengths may differ due to trait variation among plant populations and differences in herbivore pressure. My thesis demonstrates that environmental conditions and local factors, including intraspecific phenotypic variation and herbivory, both determine the nature of species interactions in salt marshes, and that the west coast of North America shows geographic patterns in interactions that are distinct from those found on the east coast.

Abiotic and Biotic Drivers of Spatial Variation in Salt Marsh Species Interactions and Community Dynamics

Abiotic and Biotic Drivers of Spatial Variation in Salt Marsh Species Interactions and Community Dynamics PDF Author: Akana Noto
Publisher:
ISBN:
Category :
Languages : en
Pages : 151

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Book Description
Interactions among members of ecological communities often vary spatially in response to environmental differences. Yet interactions can also vary spatially as a result of biotic factors such as differences in species traits or variation in other species interactions. It is necessary to understand the conditions under which each of these drivers of variation has an effect in order to predict how species interactions will be affected both by changes in the environment and in biotic communities. In this thesis, I explore mechanisms that may cause species interactions to vary across space at local, regional and continental scales in salt marsh plant communities. Chapter 1 investigates the relationship between the environment (means and variability) and community diversity and stability in time-series data from the east and west coasts of North America. Chapter 2 experimentally investigates the effect of sea-level rise on species interactions within a marsh. Chapter 3 seeks to understand geographic variation in plant interactions among six sites spanning the California coast. Chapter 4 uses a common garden experiment to test whether spatial variation in species interactions are driven by differences among plant populations or the environment. Finally, Chapter 5 describes geographic patterns of variation in herbivore pressure to determine whether herbivory drives regional differences in interactions among plants. I found that changes in mean conditions, including sea level, can affect community diversity, stability and strength of species interactions. Environmental variability only affects community stability and diversity when it is relatively large, so increases in variability with climate change may cause plant community dynamics to become affected by both variability and means. Species interactions vary geographically along the west coast, but unlike on the east coast, do not show consistent trends with latitude. Rather, interaction strengths may differ due to trait variation among plant populations and differences in herbivore pressure. My thesis demonstrates that environmental conditions and local factors, including intraspecific phenotypic variation and herbivory, both determine the nature of species interactions in salt marshes, and that the west coast of North America shows geographic patterns in interactions that are distinct from those found on the east coast.

Salt Marshes

Salt Marshes PDF Author: Duncan M. FitzGerald
Publisher: Cambridge University Press
ISBN: 1107186285
Category : Nature
Languages : en
Pages : 499

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Book Description
A multidisciplinary review of salt marshes, describing how they function and respond to external pressures such as sea-level rise.

The Role of Biotic and Abiotic Processes in the Zonation of Salt Marsh Plants in the Nueces River Delta, Texas

The Role of Biotic and Abiotic Processes in the Zonation of Salt Marsh Plants in the Nueces River Delta, Texas PDF Author: Michael Kevin Rasser
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Salt marshes provide critical ecosystem services, such as shoreline stabilization, biogeochemical cycling and habitat for wildlife, to much of the world's population living on the coasts. Emergent vascular plants are a critical component of these ecosystems. This study was a comprehensive effort to gain a better understanding of the ecology of salt marsh plants in the Nueces River delta on the south Texas coast. This knowledge is essential to understand the potential anthropogenic impacts on salt marshes, including sea-level rise, global warming, reduced freshwater inflow and coastal erosion. A combination of remote sensing analysis, field studies and experiments were used to allow analysis across spatial scales ranging from landscape patterns of vegetation to leaf level measurements of the dominant species. A novel method of image classification was developed using high-resolution multi-spectral imagery integrated with ancillary data to map the major plant communities at a landscape scale. This included a high marsh assemblage composed primarily of Spartina spartinae and a low marsh community dominated by Borrichia frutescens and Salicornia virginica. Geospatial analysis determined that the location of these plant communities was related to the distance from the tidal creek network and elevation. The B. frutescens and S. virginica assemblage was more abundant at lower elevations along the waters edge, making it vulnerable to loss from shoreline erosion. At a finer spatial scale, gradient analysis was utilized to examine the relationship between elevation, which creates environmental gradients in salt marshes, and species distribution. I discovered that elevation differences of less than 5 cm can influence both individual species and plant community distribution. One interesting finding was that the two dominant species, B. frutescens and S. virginica, share similar responses along an elevation gradient yet are observed growing in monotypic adjacent zones. I constructed a large reciprocal transplant experiment, using 160 plants at 4 sites throughout the marsh, to determine what causes the zonation between these two species. The results of this study found that S. virginica fared well wherever it was transplanted but was a weak competitor. B. frutescens survival was significantly lower in the S. virginica zone than in its own zone suggesting that abiotic factors are important in determining the zonation of this species. However, high spatial and temporal variability existed in environmental parameters such as salinity. This variability may have been caused by the semi-arid climate and irregular flooding typical in the Nueces Marsh. Therefore, I utilized a greenhouse experiment to directly test the importance of the two dominant physical factors in salt marshes, flooding and salinity. The results found that for B. frutescens the effects of flooding were not significant, however salinity at 30% reduced growth. Salinity did not influence growth of S. virginica. The greater ability of S. virginica to tolerate salinity stress has important implications because reduced freshwater inflow or climate change can increase porewater salinity, thus favoring the expansion of S. virginica, and altering the plant community structure.

Interpretation and Implications of Variability in Ecological Systems

Interpretation and Implications of Variability in Ecological Systems PDF Author: Robert Klinger
Publisher: Frontiers Media SA
ISBN: 2832551734
Category : Science
Languages : en
Pages : 206

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Book Description
Numerous hypotheses have been proposed to explain the dynamics in abundance of individual species, how species interact, how communities assemble, and how interactions between biotic and abiotic processes shape ecosystem stability. Many if not most of these hypotheses find some degree of support, but often only within relatively narrow spatial and temporal ranges. This is because conditions vary over time and from place to place, and so the strength and extent of processes that were the focus of a given a hypothesis become altered by other forces. Ecologists have confronted variability from two perspectives; conceptual and statistical. Conceptually, spatial and temporal variability are now recognized as being scale dependent and hierarchical. Statistically, there are many models that ecologists readily use that account for the hierarchical and scale-dependence of variability present in many datasets. But linking the two perspectives into a meaningful understanding of what variability means in real systems has been much less successful. For example, it is common to see studies where the fixed effects of a generalized linear mixed model are reported, but very often random effects are completely ignored or, at best, given scant attention. The likelihood of this being a significant problem increases greatly in what are rapidly becoming more common studies that utilize datasets spanning long temporal and/or large spatial scales, or when extreme and often unpredictable events (gray and black swans) occur.

Patterns and Processes of Saltmarsharea Change at Three Spatial Scales

Patterns and Processes of Saltmarsharea Change at Three Spatial Scales PDF Author: Cai J. T. Ladd
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Ecosystems around the globe are being degraded by anthropogenic activity. Coastalecosystems are considered especially vulnerable given that human populations areconcentrated at the coast. Extensive areas of saltmarsh habitat have already been lost to landreclamation, and the continued existence of natural marsh systems is in question.Understanding how saltmarsh plants interact within a changing coastal environment is seen asa vital step in protecting remaining habitat and delivering successful restoration. This thesisexamines patterns of saltmarsh change across Great Britain (GB), and the biological andenvironmental drivers responsible for change, in order to better understand marsh persistence.Studies have tended to assess marsh persistence based on their capacity to grow verticallywith sea level rise. Long-term horizontal marsh dynamics are often overlooked. Chapter 2examines 100 years of saltmarsh area change across GB and found that sea level rise andsediment supply determined whether saltmarshes expanded or eroded. All marshes werekeeping pace with sea level rise, highlighting the importance of considering horizontaldynamics in long-term marsh change.Identifying the limits on horizontal saltmarsh growth onto tidal flats has been valuable inassessing potential impacts of coastal change on open-coast marsh systems, however little workhas been done on identifying limits of marsh extent within estuaries. Chapter 3 examinessaltmarsh extent change between 1948 and 2013 in three sheltered estuaries along western GB,and shows that changes in the position of tidal channels limited marsh extent. Channelsperiodically migrated across the estuary causing marsh erosion. On the opposite bank, marshestended to expand, indicating the capacity of marshes to cycle between phases of expansion anderosion retaining a dynamic persistence within estuaries.Horizontal erosion of saltmarsh creeks causes vegetated marsh debris to accumulate at thecreek base. Indications are that these deposits limit further erosion and promote recoverythrough trapping sediment if they persist. However, biotic and abiotic controls on debrislongevity are unclear. Chapter 4 examines monthly creek change over a year and shows thatfailed bank debris with high root content slow debris erosion rates, thereby promoting sedimenttrapping and recovery. Thus, plant growth plays an important role on saltmarsh stability.By investigating marsh change over different spatio-temporal scales, a picture emerges ofhow biological and environmental drivers collectively influence change in saltmarsh extent.This offers important insight into how management interventions could target the drivers ofmarsh change at each scale in order to build marsh resilience, and is discussed in chapter 5.

Wetland Habitats of North America

Wetland Habitats of North America PDF Author: Darold P. Batzer
Publisher: Univ of California Press
ISBN: 0520271645
Category : Nature
Languages : en
Pages : 404

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Book Description
“Wetland Habitats of North America is essential reading for everyone who studies, manages, or visits North American wetlands. It fills an important void in the wetland literature, providing accessible and succinct descriptions of all of the continent’s major wetland types.” Arnold van der Valk, Iowa State University “Batzer and Baldwin have compiled the most comprehensive compendium of North American wetland habitats and their ecology that is presently available—a must for wetland scientists and managers.” Irving A. Mendelssohn, Louisiana State University "If you want to gain a broad understanding of the ecology of North America’s diverse wetlands, Wetland Habitats of North America is the book for you. Darold Batzer and Andrew Baldwin have assembled an impressive group of regional wetland scientists who have produced a virtual encyclopedia to the continent’s wetlands. Reading the book is like a road trip across the Americas with guided tours of major wetland types by local experts. Your first stop will be to coastal wetlands with eight chapters covering tidal wetlands along the Atlantic, Gulf, and Pacific coasts. Then you’ll travel inland where you can visit any or all of 18 types ranging from bottomland swamps of the Southeast to pothole marshes of the Northern Prairies to montane wetlands of the Rockies to tropical swamps of Central America and desert springs wetlands. All in one book—I’m impressed! Every wetlander should add this book to her or his swampland library. Ralph Tiner, University of Massachusetts–Amherst

Ecology of Freshwater and Estuarine Wetlands

Ecology of Freshwater and Estuarine Wetlands PDF Author: Darold P. Batzer
Publisher: Univ of California Press
ISBN: 0520278585
Category : Nature
Languages : en
Pages : 372

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Book Description
This second edition of this important and authoritative survey provides students and researchers with up-to-date and accessible information about the ecology of freshwater and estuarine wetlands. Prominent scholars help students understand both general concepts of different wetland types as well as complex topics related to these dynamic physical environments. Careful syntheses review wetland soils, hydrology, and geomorphology; abiotic constraints for wetland plants and animals; microbial ecology and biogeochemistry; development of wetland plant communities; wetland animal ecology; and carbon dynamics and ecosystem processes. In addition, contributors document wetland regulation, policy, and assessment in the US and provide a clear roadmap for adaptive management and restoration of wetlands. New material also includes an expanded review of the consequences for wetlands in a changing global environment. Ideally suited for wetlands ecology courses, Ecology of Freshwater and Estuarine Wetlands, Second Edition, includes updated content, enhanced images (many in color), and innovative pedagogical elements that guide students and interested readers through the current state of our wetlands.

Patterns and Processes of Saltmarsh Area Change at Three Spatial Scales

Patterns and Processes of Saltmarsh Area Change at Three Spatial Scales PDF Author: Cai Ladd
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description


Positive Interactions and Interdependence in Plant Communities

Positive Interactions and Interdependence in Plant Communities PDF Author: Ragan M. Callaway
Publisher: Springer Science & Business Media
ISBN: 1402062249
Category : Science
Languages : en
Pages : 419

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Book Description
This book marshals ecological literature from the last century on facilitation to make the case against the widely accepted individualistic notion of community organization. It examines the idea that positive interactions are more prevalent in physically stressful conditions. Coverage also includes species specificity in facilitative interactions, indirect facilitative interactions, and potential evolutionary aspects of positive interactions.

Trophic Ecology

Trophic Ecology PDF Author: Torrance C. Hanley
Publisher: Cambridge University Press
ISBN: 1316299694
Category : Nature
Languages : en
Pages : 427

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Book Description
As researchers try to predict the effects of human modification at all trophic levels and mediate the impact of rapid environmental change, it has become clear it is no longer a matter of agreeing that both bottom-up and top-down forces play important roles in diverse ecosystems. Rather, the question is: how do these forces interact across aquatic and terrestrial systems? Written by leading experts in the field, this book presents a unique synthesis of trophic relationships within and across ecosystems that is a valuable foundation for the development of cross-system, multidisciplinary research. It also provides new insights into population biology and community ecology and examines the interactive effects of bottom-up and top-down forces on biodiversity at each trophic level. A one-stop resource for learning about bottom-up and top-down interactions, this book encourages discussion and collaboration among researchers to identify similarities and differences in trophic interactions across aquatic and terrestrial systems.