How Much City is Too Much City? Diversity and Ecosystem Functions Along an Urban Gradient in Puget Sound
Presentation Abstract
Over half of the world’s population resides in urban areas and 44% in coastal areas. As urbanization continues, the ability of coastal marine ecosystems to provide the services people want and need from them is in question. Indeed, the extent of human activity in a region often doubles as an indicator of natural ecosystem responses to multiple stressors. For instance, habitat conversion and reclamation, harvest and hunting, and human population density are frequently assumed synonymous with reductions in the abundance of wild animal populations. However, it is surprising how rarely such assumptions are actually tested against real-world observation of the relationships between stressors and components of ecosystem structure and functions. In this study we investigated how land cover, a potential indicator of stressors such as toxic contaminants, nutrient loads, and extractive uses, related to empirically measured ecosystem responses in freshwater and marine environments of Puget Sound, WA, USA. Specifically, we estimated how four aggregate ecosystem properties varied across 12 watersheds characterized by perennial streams flowing directly into Puget Sound. These properties included freshwater and marine invertebrate diversity, primary production, secondary production, and decomposition. In addition to measuring land cover, which spanned a gradient from highly rural (>80% forested) to heavily urbanized (>80% developed), we also tracked other factors such as water temperature, salinity, stream flow, and nutrient loads. Surprisingly, aggregate properties of freshwater and marine ecosystems did not differ in a systematic way across the urban gradient. These preliminary results provide a contrast to prevailing wisdom that urban ecosystems differ dramatically from pristine ones, and suggest that land cover indicators may not always provide useful information about changes in aquatic and marine ecosystems. Because ecosystem responses can be idiosyncratic, though, this study also highlights the importance of groundtruthing stressor-ecosystem relationships to ensure that indicators are indeed meaningful.
Session Title
Session S-10D: Cross-Habitat Linkages and Landscape Scale Approaches to Ecosystem Management
Conference Track
Species and Food Webs
Conference Name
Salish Sea Ecosystem Conference (2014 : Seattle, Wash.)
Document Type
Event
Start Date
2-5-2014 1:30 PM
End Date
2-5-2014 3:00 PM
Location
Room 611-612
Genre/Form
conference proceedings; presentations (communicative events)
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Urbanization--Environmental aspects--Washington (State)--Puget Sound Watershed
Geographic Coverage
Washington (State)
Rights
This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.
Type
Text
Language
English
Format
application/pdf
How Much City is Too Much City? Diversity and Ecosystem Functions Along an Urban Gradient in Puget Sound
Room 611-612
Over half of the world’s population resides in urban areas and 44% in coastal areas. As urbanization continues, the ability of coastal marine ecosystems to provide the services people want and need from them is in question. Indeed, the extent of human activity in a region often doubles as an indicator of natural ecosystem responses to multiple stressors. For instance, habitat conversion and reclamation, harvest and hunting, and human population density are frequently assumed synonymous with reductions in the abundance of wild animal populations. However, it is surprising how rarely such assumptions are actually tested against real-world observation of the relationships between stressors and components of ecosystem structure and functions. In this study we investigated how land cover, a potential indicator of stressors such as toxic contaminants, nutrient loads, and extractive uses, related to empirically measured ecosystem responses in freshwater and marine environments of Puget Sound, WA, USA. Specifically, we estimated how four aggregate ecosystem properties varied across 12 watersheds characterized by perennial streams flowing directly into Puget Sound. These properties included freshwater and marine invertebrate diversity, primary production, secondary production, and decomposition. In addition to measuring land cover, which spanned a gradient from highly rural (>80% forested) to heavily urbanized (>80% developed), we also tracked other factors such as water temperature, salinity, stream flow, and nutrient loads. Surprisingly, aggregate properties of freshwater and marine ecosystems did not differ in a systematic way across the urban gradient. These preliminary results provide a contrast to prevailing wisdom that urban ecosystems differ dramatically from pristine ones, and suggest that land cover indicators may not always provide useful information about changes in aquatic and marine ecosystems. Because ecosystem responses can be idiosyncratic, though, this study also highlights the importance of groundtruthing stressor-ecosystem relationships to ensure that indicators are indeed meaningful.
