Browsing by Author "Holl, Karen D."

Now showing 1 - 6 of 6
  • Thumbnail Image
    Effects of landscape structure on restoration success in tropical premontane forest
    San-Jose, Miriam; Werden, Leland K.; Joyce, Francis H.; Reid, J. Leighton; Holl, Karen D.; Zahawi, Rakan A. (Nature Portfolio, 2022-08-04)
    Reversing large-scale habitat degradation and deforestation goes beyond what can be achieved by site-level ecological restoration and a landscape ecology perspective is fundamental. Here we assess the relative importance of tree cover and its configuration on forest-dependent birds and late-successional tree seedlings in restoration sites in southern Costa Rica. The abundance and species richness of birds increased in landscapes with more corridors, higher tree cover, and lower levels of fragmentation, highlighting the importance of riparian corridors for connectivity, and continuous tree cover as suitable habitat. Landscape variables affected abundance and species richness of seedlings similarly, but effects were weaker, possibly because seedlings face establishment limitation in addition to dispersal limitation. Moreover, the scale of landscape effects on seedlings was small, likely because proximal individual trees can significantly influence recruitment in restoration plots. Results underscore the importance of incorporating landscape-level metrics to restoration projects, as knowing the extent, and how the landscape may affect restoration outcomes can help to infer what kind of species will arrive to restoration plots.
  • Thumbnail Image
    Multi-scale habitat selection of key frugivores predicts large-seeded tree recruitment in tropical forest restoration
    Reid, J. Leighton; Zahawi, Rakan A.; Zarrate-Chary, Diego A.; Rosales, Juan A.; Holl, Karen D.; Kormann, Urs (Wiley, 2021-12-01)
    Large-seeded, animal-dispersed (LSAD) trees include some of the most valuable and threatened species in the tropics, but they are chronically underrepresented in regenerating forests. Toucans disperse many LSAD species, so attracting toucans to regenerating forests should help re-establish more diverse tree communities. We ask: (1) What constitutes suitable toucan habitat in premontane southern Costa Rica? (2) How much do small-scale restoration strategies influence toucan visitation compared to landscape-scale habitat suitability outside of restoration sites? (3) How well does toucan visitation predict the richness of LSAD tree species recruiting into regenerating forests? We combined habitat suitability models with long-term toucan observations and comprehensive tree recruitment surveys to assess these questions in a multi-site forest restoration experiment. Restoration treatments included tree plantations, natural regeneration, and applied nucleation. Habitat suitability obtained by modeling for three sympatric toucan species was predicted by elevation and the extent and age of landscape forest cover. Within suitable landscapes, toucans visited areas restored via tree planting ≥5 yr sooner and ≥2× more often than plots restored via natural regeneration. Tree plantations in suitable toucan habitat at the landscape scale had LSAD tree recruitment communities that were 2–3× richer in species than plantations in poor toucan habitat, and 71% (15/21) of all recruiting LSAD tree species were found only in plantations where landscape habitat was suitable for the largest toucan, Ramphastos ambiguus. Results support a multi-spatial-scale model for predicting toucan-mediated dispersal of LSAD trees. Tree planting increases toucan visitation and LSAD tree recruitment, but only within landscapes that represent suitable toucan habitat. More broadly, habitat suitability modeling for key seed dispersers can help prioritize restoration actions within heterogenous landscapes.
  • Thumbnail Image
    Recovery of Native Plant Communities After Mining
    Holl, Karen D.; Zipper, Carl E.; Burger, James A. (Virginia Cooperative Extension, 2018-03-20)
    Discusses reclamation practices in coal mined land that encourage recovery of native forested ecosystems.
  • Thumbnail Image
    Recovery of native plant communities after mining
    Holl, Karen D.; Zipper, Carl E.; Burger, James A. (Virginia Cooperative Extension, 2001)
    Coal surface mining and mine reclamation have had a significant impact on the landscape throughout the Appalachian region, including southwestern Virginia's coalfields. This fact is recognized by the Surface Mining Control and Reclamation Act (SMCRA), which states that mining operations shall establish "a diverse, effec-tive, and permanent vegetative cover of the same seasonal variety and native to the area . . . and capable of self-regeneration and plant succession ... " [Section 515(b) 19], unless introduced species are necessary to achieve the post-mining land use. Restoring the native hardwood forest is the most direct and comprehensive way of meeting this premise of SMCRA in Appalachian landscapes. Re-establishment of this self-sustaining ecosys-tem on reclaimed mines can aid in maintaining native wildlife populations while providing other valuable ecosystem services, such as erosion con-trol, carbon sequestration, wood production, water-quality improvement, and watershed pro-tection. Re-establishment of native hardwood-for-est ecosystems also contributes to the natural beauty of the Appalachian region. This publication summarizes research on the impacts of reclamation practices on re-establish-ment of native Appalachian forest ecosystems, and describes practices that may be used during reclamation to encourage re-establishment of native hardwood forest plant communities.
  • Thumbnail Image
    Recovery of Native Plant Communities After Mining
    Holl, Karen D.; Zipper, Carl E.; Burger, James A. (Virginia Cooperative Extension, 2010-02-25)
    This publication summarizes research on the impacts of reclamation practices on re-establishment of native Appalachian forest ecosystems and describes practices that may be used during reclamation to encourage re-establishment of native hardwood-forest plant communities.
  • Thumbnail Image
    Vegetational and lepidopteran conservation in rehabilitated ecosystems
    Holl, Karen D. (Virginia Tech, 1994-04-05)
    Coal surface mining and associated reclamation practices have had an immense impact on the landscape of the Appalachian region of the United States. However, their effect on floral and faunal conservation has been poorly documented. Lepidopteran communities, vegetation, and nectar resources were studied on 19 mine sites reclaimed 0-30 years previously and five sites in the surrounding hardwoods in southwestern Virginia. The goals of this work were to characterize vegetational and lepidopteran communities of these sites; to understand the relationships between the two; and to assess the role of mine reclamation in regional conservation efforts. Vegetational community composition of the reclaimed sites appeared to be approaching that of the hardwood sites as time since reclamation increased. However, it will take a number of years, if ever, before the vegetational community composition and structure approximate that of the hardwoods. Between-site variation in vegetational communities was greater in the hardwoods, than the reclaimed sites. Recently reclaimed mined sites hosted a large number of both individuals and species of diurnal lepidoptera, comprising mostly widespread, generalist species. Multivariate analysis suggested that lepidopteran community composition of reclaimed sites was approaching that of the hardwoods and that lepidopteran communities of later successional reclaimed sites were fairly similar to those of the surrounding hardwoods. Moth community composition closely reflected vegetational community composition and species richness, while butterflies were poor indicators of vegetational communities. Reclaimed sites provided much more abundant and diverse nectar resources than hardwood forests. Results of nectar studies and butterfly behavioral observations suggested that adult butterfly community composition was strongly influenced by nectar abundance, but that nectar was not a limiting resource. While reclaimed sites hosted a number of the more common plant and lepidopteran species, it remains questionable whether reclaimed areas will ever host the entire complement of the biota present prior to disturbance. In order to further conservation efforts, rehabilitation projects must be designed and monitored over larger spatial and longer temporal scales.