Abstracts, Reviews, and Meetings

To develop the following abstracts, the editorial staff searches more than 100 scientific journals, professional and organizational newsletters, conference proceedings, and other resources for information relevant to ecological restoration practice and research. Please send suggested abstract sources to the editorial staff (ERjournal@aesop.rutgers.edu).

Grasslands

A Simple Test for Alternative States in Ecological Restoration: The Use of Principal Response Curves. 2014. J.G. Alday and R.H. Marrs (School of Environmental Sciences, University of Liverpool, Liverpool, L69 3GP, UK, calluna@liv.ac.uk). Applied Vegetation Science 17:302–311.

Ecological restoration often requires that an ecosystem be flipped from one self-sustaining state to another by overcoming the presently degraded system’s resistance to such change; an application of the concept of alternative stable states. Alday and Marrs provide a practical test for this otherwise abstract concept using principal response curves (PRC) in acid grasslands and heathlands invaded by western brackenfern (Pteridium aquilinum) in Great Britain. PRC were used to detect whether alternative states (i.e. native grasslands and heathlands) were created by controlling brackenfern. Species responses to restoration treatments in terms of plant community composition were analyzed using PRC to measure the restored ecosystem’s state relative to the untreated baseline. Cutting brackenfern twice per year overcame the resistance of the starting community and achieved the heathland or grassland alternative state, and even a “one-off” single treatment of herbicide created an alternative stable state in the grassland community for 10 years. However, these restored alternative states may not be stable in the longterm in the absence of continued treatment.

Restoration of a Megaherbivore: Landscape-level Impacts of White Rhinoceros in Kruger National Park, South Africa. 2014. J.P.G.M. Cromsigt (Department of Wildlife, Fish, and Environmental Studies, Swedish University of Agricultural Sciences, Umeå 901 83, Sweden, jcromsigt@hotmail.com) and M. te Beest. Journal of Ecology 102:566–575.

Megaherbivores are often keystone species in the ecosystems they inhabit and their loss from ecosystems across the globe can result in cascading changes in ecological communities. While many studies of megaherbivore loss focus on African elephants, Cromsigt and te Beest tested how restoration of white rhinoceros (Ceratotherium simum) populations affects the structure of savanna grasslands in Krugaer National Park (KNP), South Africa. White rhinoceros were extirpated from KNP in 1896 due to over-hunting and were reintroduced in the 1960s. Landscapes with high densities of white rhinoceros that were recolonized early in the reintroduction process were compared to those with low rhino densities and more recent recolonization. Short grass cover and grazing lawns (2 m areas with > 50% cover of stoloniferous, prostrate-growing grass species) were higher in the areas with higher rhino impact. The authors suggest that the current megaherbivore poaching crisis may not only be affecting the white rhinoceros but also the structure and function of the savanna ecosystem.

Impacts of Mulch on Prairie Seedling Establishment: Facilitative to Inhibitory Effects. 2014. F. Mollard (Department of Renewable Resources, University of Alberta, Canada), M. Naeth and A. Cohen-Fernandez. Ecological Engineering 64:377–384.

Practitioners have long known that applying mulch on arid or semiarid sites after hydroseeding will boost seedling establishment and emergence rates by keeping the soil moist and the seeds in place, but mulch may also inhibit or have no affect on emergence and establishment. So how do you maximize a reclamation budget and see the most establishment in that critical first year of growth? Mollard and colleagues tested this using two mulch types (rangeland hay and wheat straw), applied at two different rates, in an abandoned irrigation site in Alberta, Canada. The good news for practitioners is that the lower mulch rate (300 g m²) was more beneficial for emergence and establishment compared to bare ground or the higher application rate. Mollard cautioned that their results are species-specific, and mulch type and rate should be evaluated on a site-by-site basis.

Making Sense of a Prairie Butterfly Paradox: The Effects of Grazing, Time Since Fire, and Sampling Period on Regal Fritillary Abundance. 2014. R. Moranz (Department of Zoology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK, USA 74078, raymond. moranz@okstate.edu), S. Fuhlendorf and...