Article
Plant Sciences
Piet Monegi, Ntuthuko Raphael Mkhize, Julius Tlou Tjelele, David Ward, Zivanai Tsvuura
Summary: This study investigated the effects of different tree removal treatments and herbicide application on the resprouting ability and vigour of 12 woody plant species. The results showed that woody plants are more likely to resprout and survive as juveniles than as adults, and only a few species were affected by the herbicide. This information is important for land users in southern African savannas.
Article
Plant Sciences
Michael D. Voysey, Sally Archibald, William J. Bond, Jason E. Donaldson, A. Carla Staver, Michelle Greve
Summary: In savannas, heavy grazing by wildlife tends to result in lower woody cover, with browsing mesoherbivores and mixed feeders attracted to short-grass habitats and helping to maintain openness by suppressing seedling survival and woody plant growth.
JOURNAL OF ECOLOGY
(2021)
Article
Ecology
Eric M. LaMalfa, Corinna Riginos, Kari E. Veblen
Summary: The study found that wildlife had a positive effect on sapling growth while moderate cattle grazing did not have a significant impact. Grass removal treatments and neighborhood tree effects on saplings were strongest during above-average rainfall years.
ECOLOGICAL APPLICATIONS
(2021)
Article
Plant Sciences
Samuel W. Flake, Eliane A. Honda, Natashi A. L. Pilon, William A. Hoffmann, Giselda Durigan
Summary: The encroachment of forests into savannas is a common phenomenon, with the rate depending on factors such as soil conditions, species composition, and changes in stand structure. Savanna specialist trees are being replaced by generalist species, causing faster rates of stand development. Generalists are able to persist in forests and have faster growth rates, enabling them to outcompete and suppress savanna specialists.
JOURNAL OF ECOLOGY
(2022)
Article
Ecology
Lucia S. Mochi, Noemi Mazia, Fernando Biganzoli, Martin R. Aguiar
Summary: The study found that cattle grazing had a neutral effect on woody recruitment in tropical savannas, as it reduced seed predation but negatively impacted seedling survival. Herbaceous vegetation had contrasting effects on the seed and seedling stages of woody plants.
BASIC AND APPLIED ECOLOGY
(2022)
Article
Multidisciplinary Sciences
Melissa H. Schmitt, Keenan Stears, Mary K. Donovan, Deron E. Burkepile, Dave Thompson
Summary: This study examines the impact of different levels of woody vegetation cover on herbivore assemblages in African savannas. The research reveals that habitats with intermediate woody cover have higher species richness and abundance, while areas with intensive tree clearing or high tree cover have lower species richness and abundance.
Article
Ecology
Brandon R. Hays, Corinna Riginos, Todd M. Palmer, Daniel F. Doak, Benard C. Gituku, Nelly J. Maiyo, Samuel Mutisya, Simon Musila, Jacob R. Goheen
Summary: Biological invasion can disrupt mutualisms, as shown by the invasive big-headed ant's impact on the mutualism between the whistling-thorn tree and native ants in a Kenyan savanna. The invasion exacerbated population declines of the tree, but the presence of large mammalian herbivores had an even greater negative impact. Expulsion of native mutualists did not lead to higher population growth rates for the tree.
Article
Ecology
Brad S. Ripley, Sarah L. Raubenheimer, Lavinia Perumal, Maurice Anderson, Emma Mostert, Barney S. Kgope, Guy F. Midgley, Kimberley J. Simpson
Summary: The study found that increased levels of CO2 can enhance the tolerance of Vachellia karroo seedlings to herbivory by promoting growth and allowing them to reach a critical size threshold earlier, thus reducing the likelihood of fatal herbivory. However, increased CO2 levels do not affect leaf palatability and defense capabilities of the tree.
FUNCTIONAL ECOLOGY
(2022)
Article
Forestry
Lucia S. Mochi, Martin R. Aguiar, Melina J. Aranda, Fernando Biganzoli, Noemi Mazia
Summary: Livestock rearing is increasing in savannas, and the ability of trees to regrow after consumption is crucial for savanna structure and functioning. This study identified specific traits that may explain the mechanisms behind defoliation tolerance in saplings of two encroacher tree species. The experiments showed that defoliation decreased growth but did not affect relative growth rate, and increased the number of branches per plant and decreased root relative growth rate. The study highlights the potential impact of livestock grazing on tree growth rates and management in savanna ecosystems.
FOREST ECOLOGY AND MANAGEMENT
(2023)
Article
Plant Sciences
Karin Amsten, Joris P. G. M. Cromsigt, Dries P. J. Kuijper, Jenny M. Loberg, Marcin Churski, Mats Niklasson
Summary: Fire and herbivory are fundamental processes that can strongly influence the recruitment of European temperate tree saplings. Different tree species showed varying responses to these disturbances, with some exhibiting tolerance and others opting for avoidance strategies. The experiment conducted in a wood-pasture highlighted the potential importance of fire and herbivory as drivers of structure and species composition in open ecosystems in temperate Europe in the past.
JOURNAL OF ECOLOGY
(2021)
Article
Ecology
Yong Zhou, Morgan W. Tingley, Madelon F. Case, Corli Coetsee, Gregory A. Kiker, Rheinhardt Scholtz, Freek J. Venter, A. Carla Staver
Summary: The study in Kruger National Park found that woody encroachment is widespread and highly variable, resulting in an increase in the number of common woody species and stem density. While local management can influence woody encroachment to some extent, it is limited by drivers beyond local control. Regular field sampling coupled with targeted fire management is recommended for more accurate monitoring of encroachment intensification.
ECOLOGICAL APPLICATIONS
(2021)
Article
Biodiversity Conservation
Tercia Strydom, Izak P. J. Smit, Navashni Govender, Corli Coetsee, Jenia Singh, Andrew B. B. Davies, Brian W. W. van Wilgen
Summary: Woody thickening or 'bush encroachment' is a global concern in savannas, and high-intensity fires were initially thought to reverse it. However, after 10 years of monitoring, it was found that the different fire treatments did not result in a significant difference in woody encroachment, indicating that high-intensity fires may not be an effective solution.
JOURNAL OF APPLIED ECOLOGY
(2023)
Article
Ecology
Dillon T. Fogarty, Robert B. Peterson, Dirac Twidwell
Summary: This study develops a recruitment curve to describe the scatter of woody plant recruitment around seed sources and examines how this structures spatial patterns of encroachment.
Article
Forestry
Austin M. Yantes, Samuel P. Reed, Anna M. Yang, Rebecca A. Montgomery
Summary: Temperate savannas are unique and biodiverse ecosystems that have experienced extensive habitat conversion worldwide. In the midwestern United States, the majority of historic oak savanna area has been lost, and the remaining patches are degraded due to the absence of fire and large herbivore disturbances. Restoring the degraded savanna remnants is challenging due to a lack of understanding of how to effectively mimic historic disturbance dynamics.
FOREST ECOLOGY AND MANAGEMENT
(2023)
Article
Ecology
David A. Loewensteiner, Renee E. Bartolo, Timothy G. Whiteside, Andrew J. Esparon, Chris L. Humphrey
Summary: The maturity of remote sensing and ecosystem restoration science allows for monitoring and assessing ecosystem indicators at finer resolutions and suitable scales, providing new opportunities for ecosystem restoration projects. Woody cover in savanna woodland ecosystems plays a vital role and can be effectively measured using remote sensing techniques, serving as a reference for restoration trajectories and monitoring activities.