Reproductive failure of a long-lived wetland tree in urban lands and managed forests

    Authors

    L. A. McCauley; D. G. Jenkins;P. F. Quintana-Ascencio

    Comments

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    Abbreviated Journal Title

    J. Appl. Ecol.

    Keywords

    biological inertia; cypress dome; fire; Florida; forest management; hydrology; isolated wetlands; recruitment; south-eastern US; urbanization; PRESCRIBED FIRE; BIOLOGICAL INERTIA; EXTINCTION DEBT; UNITED-STATES; URBANIZATION; CONSERVATION; BIODIVERSITY; FLORIDA; RESTORATION; RESPONSES; Ecology

    Abstract

    Land use (e.g. urbanization, agriculture, natural lands management) may directly affect populations by habitat loss and fragmentation, and indirectly by altering conditions needed for reproductive success. The effects of urbanization are especially pronounced for populations that remain among urbanized areas, but they are difficult to detect in long-lived species. We evaluated the effects of urbanization on the recruitment of cypress (Taxodium distichum), a long-lived coniferous tree that dominates isolated wetlands in Orlando, Florida, USA, a rapidly urbanizing region. Cypress requires saturated but not flooded soils to germinate, and seedlings are easily out-competed in the absence of fire. We hypothesized that urbanization has altered the hydrology and fire regimes, leading to biological inertia and reduced cypress recruitment relative to managed forest and ranchland. We found low cypress recruitment in urban areas, but surprisingly in managed forest as well. Many cypress populations in managed forest were bounded by fire breaks which prevent upland fires from burning into the wetlands. Ranchland had significantly more recruitment than urban and managed forest, and these wetlands did not have fire breaks. In urban lands, the effects of urbanization were delayed. Cypress recruitment initially occurred near the edge of wetlands where hydrological conditions were most favourable, but virtually stopped at 20years post-urbanization. Cypress recruitment also occurred near the edge of the wetlands in managed forests and ranchlands and was higher in larger wetlands. Synthesis and applications. Urbanization is associated with the eventual reproductive failure of cypress and in the absence of management practice changes, cypress recruitment may cease in many additional wetlands. If past urbanization rates continue, 8090% of cypress populations in isolated wetlands in the path of urban sprawl could permanently cease recruitment in 100years. Reducing urban sprawl and introducing prescribed fire in managed-forest cypress domes could mitigate this effect and conserve reproduction of this long-lived, dominant tree species and the diversity of the wetlands they typify.

    Journal Title

    Journal of Applied Ecology

    Volume

    50

    Issue/Number

    1

    Publication Date

    1-1-2013

    Document Type

    Article

    Language

    English

    First Page

    25

    Last Page

    33

    WOS Identifier

    WOS:000314520500004

    ISSN

    0021-8901

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