Down by the riverside: urban riparian ecology

Riparian areas are hotspots of interactions between plants, soil, water, microbes, and people. While urban land use change has been shown to have dramatic effects on watershed hydrology, there has been surpris- ingly little analysis of its effects on riparian areas. Here we examine the ecology of urban riparian zones, focusing on work done in the Baltimore Ecosystem Study, a component of the US National Science Foundation's Long Term Ecological Research network. Research in the Baltimore study has addressed how changes in hydrology associated with urbanization create riparian "hydrologic drought" by lowering water tables, which in turn alters soil, vegetation, and microbial processes. We analyze the nature of past and cur- rent human interactions with riparian ecosystems, and review other urban ecosystem studies to show how our observations mirror those in other cities

Landscape Dynamics in the Wildland-Urban Interface

Abstract The wildland-urban interface represents landscape change-changes brought about by urbanization, by shifts in forest management, and altered disturbance regimes, each having ecological, social, and economic ramifications. In this chapter, I will focus on some of the ecological ramifications associated with landscape change, primarily forest fragmentation and deforestation, resulting from urbanization. In particular, I will review forest fragmentation from a landscape and site perspective; examine the ecological aspects of edges, corridors, and roads; and discuss fragmentation in relation to human health issues as they pertain to the wildland-urban interface. Forest Fragmentation In 1967, Forest fragmentation and loss are landscape processes. A review of the fragmentation literature, however, reveals a set of terms-such as habitat loss, habitat fragmentation, and habitat degradation-also being used to describe forest fragmentation. Following Forman (1995) conceptualized human modification of forested landscapes into five pro

Characterization of Masticated Fuelbeds and Fuel Treatment Effectiveness in Southeastern US Pine Ecosystems.

Mechanical fuels treatments are being widely used in fire prone ecosystems where fuel loading poses a hazard, yet little research examining fuel dynamics, fire behavior, and ecological effects exists, especially in the southeastern US. In order to broaden our understanding of these treatments, effects of mechanical mastication ( mowing ) were examined in a common pine ecosystem of the southeastern US Coastal Plain, where the post-mastication fuel environment is unique among ecosystems where mastication is being employed. Foliar litter dominates surface fuels after understory mastication in palmetto/gallberry pine flatwoods, however rapid recovery of shrubs quickly regains control over fire behavior. Treatments were effective at reducing flame heights during post-treatment prescribed burning in these sites, however compact surface fuels were observed to cause long-duration heating during laboratory burning. Overstory tree mortality observed following summer burning in mowed treatments may have resulted from combustion of the compact surface fuels beneath the shrub layer. Although temperature and humidity at the shrub level were minimally impacted, drier surface fuels existed in masticated sites where shrub cover was reduced, potentially exacerbating combustibility of the surface fuel layer. Treatments had little impact on understory vegetation communities or soil nutrients, however, observed reduction in saw palmetto may alter future groundcover, as slight increases in grass cover were observed. The fast recovery of understory vegetation and generally low impact to ecosystem attributes suggest resiliency of these pine flatwoods following mechanical treatments. However, their effectiveness at reducing fire hazard is likely short-lived. Treatment regimes that utilize prescribed burning to reduce post-mastication fuels will require special attention to treatment timing in order to ensure surface litter consumption, while minimizing potential impacts to the overstory

Un marco para desarrollar indicadores de bienes y servicios de los ecosistemas forestales urbanos

The social and ecological processes impacting on urban forests have been studied at multiple temporal and spatial scales in order to help us quantify, monitor, and value the ecosystem services that benefit people. Few studies have comprehensively analyzed the full suite of ecosystem services, goods (ESG), and ecosystem disservices provided by an urban forest. Indicators, however, are one approach that could be used to better understand the structure of an urban forest, the suite of ESG provided by urban forests, and their influence on human well-being using a simple, innovative and repeatable metric. This study presents a framework for developing indicators using field data, an urban forest functional model, and the literature. Urban tree and soil indicators for groups of ecosystem functions were used to statistically analyze the effects of urban morphology and socioeconomics on urban forest ESG. Findings show that the most influential ESG indicators were tree cover, soil pH, and soil organic matter. Indicators were significantly influenced by land use and time since urbanization, while analyses of property values and household income did not yield any particularly significant results. The indicators presented in this paper present a first approach to non-monetary valuation of urban forest ESG and can be used to develop urban forest structure management goals and to monitor the effects of urban greening policies on human well-being

Projecting Land-Use and Land Cover Change in a Subtropical Urban Watershed

Urban landscapes are heterogeneous mosaics that develop via significant land-use and land cover (LULC) change. Current LULC models project future landscape patterns, but generally avoid urban landscapes due to heterogeneity. To project LULC change for an urban landscape, we parameterize an established LULC model (Dyna-CLUE) under baseline conditions (continued current trends) for a sub-tropical urban watershed in Tampa, FL. Change was modeled for 2012–2016 with observed data from 1995–2011. An ecosystem services-centric classification was used to define 9 LULC classes. Dyna-CLUE projects change using two modules: non-spatial quantity and spatial reallocation. The data-intensive spatial module requires a binomial logistic regression of socioecological driving factors, maps of restricted areas, and conversion settings, which control the sensitivity of class-to-class conversions. Observed quantity trends showed a decrease in area for agriculture, rangeland and upland forests by 49%, 56% and 27% respectively with a 22% increase in residential and 8% increase in built areas, primarily during 1995–2004. The spatial module projected future change to occur mostly in the relatively rural northeastern section of the watershed. Receiver-operating characteristic curves to evaluate driving factors averaged an area of 0.73 across classes. The manipulation of these baseline trends as constrained scenarios will not only enable urban planners to project future patterns under many ecological, economic and sociological conditions, but also examine changes in urban ecosystem services