Author Correction: Drivers of seedling establishment success in dryland restoration efforts

1 Pág. Correción errata.In the version of this Article originally published, the surname of author Tina Parkhurst was incorrectly written as Schroeder. This has now been corrected.Peer reviewe

Livestock grazing has minimal effect on the species richness and diversity of semi-arid shrubland in the Western Little Karoo, South Africa

The Succulent Karoo, one of two arid biodiversity hotspots in the world, is known for its high plant species richness, but little is known about the influence of topography and how it mediates the potentially deleterious effects of grazing. Changes in vegetation species composition, cover and species diversity were examined along piosphere gradients on northerly slopes, bottomlands and low-lying plains on 45 farms. Landscapes differed in the plant species- and life-form composition, species richness and cover, with the more species-rich, heterogeneous grassy northerly slopes distinct from the plains and bottomlands, which were dominated by Pteronia pallens, Psilocaulon junceum and Drosanthenum spp. with more annual and ephemeral species. Overall, species richness declined linearly with decreasing rangeland condition. A weak grazing effect was detected only on the north-facing slopes, where shrubs and grass decreased with intense grazing. Years of overgrazing have resulted in the widespread dominance of P. pallens, especially on the plains and bottomlands, rendering them insensitive to grazing. The current condition of the northern slopes should be maintained and managed such that palatable species can spread to more degraded areas of the landscape.Keywords: cover, evenness, piosphere effect, species richness, veld conditio

Research NoteIdentifying key grazing indicators to monitor trends in the veld condition of Lambert’s Bay Strandveld, South Africa

Currently, the methods used to assess the veld condition of the Lambert’s Bay Strandveld along the West Coast of South Africa require that the operator knows all the plants encountered in the survey area. In this study data were collected from several farms in the Lambert’s Bay Strandveld to establish a degradation gradient from which a minimum number of species necessary to monitor trends in the condition of the veld were determined, making it user-friendly for land-users, extension officers and others. The key indicators were also tested using a second set of data.Keywords: arid, management (natural resources), monitoring, rangeland condition, winter rainfallAfrican Journal of Range & Forage Science 2014, 31(1): 43–4

Possible rehabilitation methods of Galenia africana-dominated old lands in the Cederberg Mountains, South Africa

Several methods to rehabilitate old cropping lands in the Cederberg Mountains were tested to determine what type of soil disturbance, if any, and which of five indigenous perennial plant species are the most successful and economically feasible. Old lands are dominated by the unpalatable and poisonous, pioneer perennial Galenia africana. A complete randomised block design was followed with eight treatments and four replicates. All treatments, excluding the control, included re-seeding with five palatable species from the region. Soil disturbance was important with best results after three years in the ploughing-and-seeding and rolling-and-seeding treatments, which were also the most cost-effective treatments. Rainfall played a major role, with good germination in year one, but after a dry summer most of the new seedlings died. After three years the grasses Chaetobromus involucratus subsp. dregeanus and Ehrharta calycina, followed by the dwarf shrub Tripteris sinuata, established the best, but less than 1% of the seed sown established. The near-absence of perennial species in the soil seedbank and above ground necessitate the addition of seed. In conjunction with this, applying mechanical soil disturbance using an environmentally-friendly method, such as a knife roller, is advised to rehabilitate old croplands to a more productive state for herbivores.Keywords: indigenous perennial species, improved forage, re-seeding, soil disturbance, species diversit

Drivers of seedling establishment success in dryland restoration efforts

Restoration of degraded drylands is urgently needed to mitigate climate change, reverse desertification and secure livelihoods for the two billion people who live in these areas. Bold global targets have been set for dryland restoration to restore millions of hectares of degraded land. These targets have been questioned as overly ambitious, but without a global evaluation of successes and failures it is impossible to gauge feasibility. Here we examine restoration seeding outcomes across 174 sites on six continents, encompassing 594,065 observations of 671 plant species. Our findings suggest reasons for optimism. Seeding had a positive impact on species presence: in almost a third of all treatments, 100% of species seeded were growing at first monitoring. However, dryland restoration is risky: 17% of projects failed, with no establishment of any seeded species, and consistent declines were found in seeded species as projects matured. Across projects, higher seeding rates and larger seed sizes resulted in a greater probability of recruitment, with further influences on species success including site aridity, taxonomic identity and species life form. Our findings suggest that investigations examining these predictive factors will yield more effective and informed restoration decision-making.6 month embargo; published: 22 July 2021This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]