Influence of urbanization on riparian forest diversity and structure in the Georgia Piedmont, US

Riparian forests are increasingly threatened by urban expansion and land use change worldwide. This study examined the relationships between landscape characteristics and woody plant diversity, structure, and composition of small order riparian corridors along an urban-rural land use gradient in the Georgia Piedmont, US. Riparian plant diversity, structure, and composition were related to landscape metrics and land use. Species richness was negatively associated with impervious surfaces and landscape diversity, and positively associated with forest cover and largest forest patch index. Shannon species diversity was strongly related to the biomass of non-native species, especially for the regeneration layer. Urban sites were characterized by high richness of non-native and pioneer species. Developing sites were dominated by the non-native shrub, Ligustrum sinense Lour., and several native overstory trees, mainly Acer negundo L. While agricultural and managed forest sites were composed of ubiquitous species, unmanaged forest sites had a structurally distinct midstory indicative of reduced disturbance. Urban and agricultural land uses showed decreased native stem densities and signs of overstory tree regeneration failure. Results from this study highlight the impact of the surrounding landscape matrix upon riparian forest plant diversity and structure.

[1]  Alexander Clark,et al.  Weight, Volume, and Physical Properties of Major Hardwood Species in the Gulf and Atlantic Coastal Plains , 1985 .

[2]  J. P. Grime.  Declining plant diversity: empty niches or functional shifts? , 2002 .

[3]  M. McKinney,et al.  Urbanization as a major cause of biotic homogenization , 2006 .

[4]  M. Hill,et al.  Data analysis in community and landscape ecology , 1987 .

[5]  D. Levia,et al.  Recruitment of three non-native invasive plants into a fragmented forest in southern Illinois , 2004 .

[6]  G. Guntenspergen,et al.  Understory plant species composition in remnant stands along an urban-to-rural land-use gradient , 1997, Urban Ecosystems.

[7]  R. Pouyata,et al.  Soil carbon pools and fluxes in urban ecosystems , 2009 .

[8]  Ralph D. Nyland,et al.  Silviculture: Concepts and Applications , 1996 .

[9]  S. Pan,et al.  Detection of biotic responses to urbanization using fish assemblages from small streams of western Georgia, USA , 2005, Urban Ecosystems.

[10]  H. Ikeda.  Testing the intermediate disturbance hypothesis on species diversity in herbaceous plant communities along a human trampling gradient using a 4-year experiment in an old-field , 2003, Ecological Research.

[11]  R. Birdsey,et al.  National-Scale Biomass Estimators for United States Tree Species , 2003, Forest Science.

[12]  W. Judd,et al.  Trees, Shrubs, and Woody Vines of Northern Florida and Adjacent Georgia and Alabama , 1989 .

[13]  P. Balvanera,et al.  Quantifying the evidence for biodiversity effects on ecosystem functioning and services. , 2006, Ecology letters.

[14]  S. Pan,et al.  Riparian woody plant diversity and forest structure along an urban-rural gradient , 2005, Urban Ecosystems.

[15]  V. M. Conway,et al.  Deciduous Forests of Eastern North America. , 1951 .

[16]  C. M. Cowell.  Historical Change in Vegetation and Disturbance on the Georgia Piedmont , 1998 .

[17]  D. M. Sharpe,et al.  Fate of natural vegetation during urban development of rural landscapes in Southeastern Wisconsin , 1986 .

[18]  N. Kenkel,et al.  Impacts of land use on riparian forest along an urban – rural gradient in southern Manitoba , 2004, Plant Ecology.

[19]  Jessica Gurevitch,et al.  Effects of an invasive tree on community structure and diversity in a tropical forest in Puerto Rico , 2006 .

[20]  W. Zipperer.  Species composition and structure of regenerated and remnant forest patches within an urban landscape , 2002, Urban Ecosystems.

[21]  Marie-Josée Fortin,et al.  SPATIAL ANALYSIS OF LANDSCAPES: CONCEPTS AND STATISTICS , 2005 .

[22]  R. Sidle,et al.  Understanding Processes and Downstream Linkages of Headwater Systems , 2002 .

[23]  Jiquan Chen,et al.  Vegetation responses to landscape structure at multiple scales across a Northern Wisconsin, USA, pine barrens landscape , 1999, Plant Ecology.

[24]  R. Merriam,et al.  The Potential Impact of An Introduced Shrub on Native Plant Diversity and Forest Regeneration , 2002, Biological Invasions.

[25]  Lawrence E. Band,et al.  Down by the riverside: urban riparian ecology , 2003 .

[26]  W. Bond,et al.  Regeneration failure and the potential importance of human disturbance in a subtropical forest , 2000 .

[27]  M. O. Hill,et al.  DECORANA - A FORTRAN program for detrended correspondence analysis and reciprocal averaging. , 1979 .

[28]  S. Trimble,et al.  Man-induced soil erosion on the Southern Piedmont, 1700-1970. , 2008 .

[29]  S. Díaz,et al.  Vive la différence: plant functional diversity matters to ecosystem processes , 2001 .

[30]  F. Chapin,et al.  EFFECTS OF BIODIVERSITY ON ECOSYSTEM FUNCTIONING: A CONSENSUS OF CURRENT KNOWLEDGE , 2005 .

[31]  Andrew J. Hansen,et al.  EFFECTS OF EXURBAN DEVELOPMENT ON BIODIVERSITY: PATTERNS, MECHANISMS, AND RESEARCH NEEDS , 2005 .

[32]  R. Král,et al.  Trees, Shrubs, and Woody Vines of Northern Florida and Adjacent Georgia and Alabama , 1989 .

[33]  B. G. Lockaby,et al.  Interdisciplinary research at the Urban–Rural interface: The West ga project , 2005, Urban Ecosystems.

[34]  M. Dobson,et al.  Riparian plant species loss alters trophic dynamics in detritus-based stream ecosystems , 2005, Oecologia.

[35]  W. Zipperer,et al.  Ecosystem processes along an urban-to-rural gradient , 2005, Urban Ecosystems.

[36]  Jeffrey A. Stratford,et al.  Distribution of neotropical migratory bird species across an urbanizing landscape , 2005, Urban Ecosystems.

[37]  R. Blair,et al.  Woody vegetation and canopy fragmentation along a forest-to-urban gradient , 2001, Urban Ecosystems.

[38]  Monica G. Turner,et al.  Landscape indicators of human impacts to riverine systems , 2002, Aquatic Sciences.

[39]  J. Walck,et al.  Growth and Reproduction of the Invasive Ligustrum sinense and Native Forestiera ligustrina (Oleaceae): Implications for the Invasion and Persistence of a Nonnative Shrub , 2002, International Journal of Plant Sciences.

[40]  J. Lyons,et al.  Impacts of Urbanization on Stream Habitat and Fish Across Multiple Spatial Scales , 2001, Environmental management.

[41]  S. Pickett,et al.  Ecosystem Structure and Function along Urban‐Rural Gradients: An Unexploited Opportunity for Ecology , 1990 .

[42]  D. Currie,et al.  THE DIVERSITY–DISTURBANCE RELATIONSHIP: IS IT GENERALLY STRONG AND PEAKED? , 2001 .

[43]  Steward T. A. Pickett,et al.  THE APPLICATION OF ECOLOGICAL PRINCIPLES TO URBAN AND URBANIZING LANDSCAPES , 2000 .

[44]  Andrew W. Western,et al.  A review of paired catchment studies for determining changes in water yield resulting from alterations in vegetation , 2005 .

[45]  R. Naiman,et al.  The Ecology of Interfaces: Riparian Zones , 1997 .

[46]  Carl C. Trettin,et al.  Biomass and carbon pools of disturbed riparian forests , 2003 .

[47]  B. McCune,et al.  Analysis of Ecological Communities , 2002 .

[48]  J. Kauffman,et al.  Riverscape-level patterns of riparian plant diversity along a successional gradient, Willamette river, Oregon , 2006, Plant Ecology.

[49]  M. Ter-Mikaelian,et al.  Biomass equations for sixty-five North American tree species , 1997 .

[50]  Robert B. Blair,et al.  Butterfly diversity and human land use: Species assemblages along an urban gradient , 1997 .

[51]  Donald E. Weller,et al.  SPATIAL CONSIDERATIONS FOR LINKING WATERSHED LAND COVER TO ECOLOGICAL INDICATORS IN STREAMS , 2005 .

[52]  S. Pickett,et al.  Forest-Landscape Structure along an Urban-To-Rural Gradient* , 1995, The Professional Geographer.

[53]  W. Mitsch,et al.  Estimating primary productivity of forested wetland communities in different hydrologic landscapes , 1991, Landscape Ecology.

[54]  E. F. Loewenstein,et al.  Non-native plants in the understory of riparian forests across a land use gradient in the Southeast , 2005, Urban Ecosystems.

[55]  R. Aragón,et al.  Recruitment limitation in secondary forests dominated by an exotic tree , 2004 .

[56]  B. G. Lockaby,et al.  Changes in chemical and physical propertiesof stream water across an urban-rural gradient in western Georgia , 2005, Urban Ecosystems.

[57]  David L. Loftis,et al.  Oak Regeneration: A Knowledge Synthesis , 1997 .

[58]  N. L. Johnson,et al.  Continuous Univariate Distributions. , 1995 .

[59]  P. Groffman,et al.  Denitrification potential in urban riparian zones. , 2003, Journal of environmental quality.

[60]  S. Cordell,et al.  Effects of non-native grass invasion on aboveground carbon pools and tree population structure in a tropical dry forest of Hawaii , 2006 .

[61]  Laura A. Hyatt,et al.  INVASIVE SPECIES ACCELERATE DECOMPOSITION AND LITTER NITROGEN LOSS IN A MIXED DECIDUOUS FOREST , 2005 .

[62]  D. Gorchov,et al.  The invasive shrub, Lonicera maackii , reduces growth and fecundity of perennial forest herbs , 2004, Oecologia.

[63]  Kenneth M. Johnson,et al.  Rural land-use trends in the conterminous United States, 1950-2000 , 2005 .

[64]  G. Austrheim,et al.  Plant diversity patterns in semi-natural grasslands along an elevational gradient in southern Norway , 2002, Plant Ecology.

[65]  D. Urban,et al.  Spatial pattern ofQuercusregeneration limitation andAcer rubruminvasion in a Piedmont forest , 2003 .

[66]  Birgitta Malm Renöfält,et al.  Spatial patterns of plant invasiveness in a riparian corridor , 2005, Landscape Ecology.

[67]  Sang Joon Kim,et al.  A Mathematical Theory of Communication , 2006 .

[68]  S. Pickett,et al.  Effect of Edge Structure on the Flux of Species into Forest Interiors , 2001 .

[69]  A. Clark,et al.  Weight, Volume, and Physical Properties of Major Hardwood Species in the Upland-South , 1986 .