Find research datasets worth reusing

Search datasets from major research repositories and use ShareScore to quickly assess how well each record supports discovery, access, and reuse.

datasets available to search

ShareScore release 0.9.0

Dataset results

36 results for “woody encroachment”

Learn how ShareScore rates datasets ↗

dryad32/100

Ecosystem sulfur accumulation following woody encroachment drives a more open S-cycle in a subtropical savanna

Globally widespread woody encroachment into grass-dominated ecosystems has substantial consequences for carbon (C), nitrogen (N), and phosphorus (P) cycles. Despite its significance as an essential macronutrient, however, little is known regarding potential changes in the sulfur (S) cycle. We quantified S concentrations, stoichiometric relationships, and δ34S values in the plant-soil environment to investigate landscape-scale changes in the S cycle following grassland-to-woodland transitions in a subtropical savanna. Plant tissues of woody species had significantly higher S concentrations and δ34S values than those of herbaceous species, resulting in a landscape-scale correspondence between spatial patterns of S and δ34S in surface soils and vegetation distribution, with higher S and δ34S in soils beneath woody patches. These patterns were more subtle at soil depths > 5 cm. Woody plants had higher N:S ratios but comparable P:S ratios relative to herbaceous species, which contributed to contrasting spatial patterns between N:S and P:S ratios in surface soils. Sulfur in surface soils increased proportionally less relative to N, but proportionally more compared to P. Our findings indicate that grassland-to-woodland transitions amplify landscape-scale S dynamics, especially in surface soils, and create a S-enriched environment that enables woody plants to acquire sufficient S relative to demand to support their continued productivity and proliferation.

opencc-zeroJun 2021View details →

dryad32/100

Facilitation by isolated trees triggers woody encroachment and a biome shift at the savanna-forest transition

1. Woody encroachment into grassy biomes is a global phenomenon, often resulting in a nearly complete turnover of species, with savanna specialists being replaced by forest-adapted species. Understanding the mechanisms involved in this change is important for devising strategies for managing savannas. 2. We examined how isolated trees favor woody encroachment and species turnover by overcoming dispersal limitation and environmental filtering. In a savanna released from fire in southeastern Brazil (Cerrado) we sampled woody plants establishing under 40 tree canopies and in paired treeless plots. These trees comprised eight species selected for habitat preference (savanna or forest) and dispersal syndrome (bird-dispersed or not). We recorded dimensions of each tree, dispersal syndrome and habitat preference of recruits, and quantified the physical environment within each plot, aiming at a mechanistic understanding of woody encroachment. 3. We found clear evidence that isolated trees cause nucleation and drive changes in functional composition of savanna. Effectiveness as nucleator differed among species, but was unrelated to their functional guilds (habitat preference or dispersal syndrome). Density of saplings in nuclei was partially explained by soil moisture (+), daily temperature amplitude (-), and sum of bases (-). 4. Our results indicate that isolated trees act first as perches, strongly favoring bird-dispersed species. They then act as nurse trees, considerably changing the environment in favor of forest-adapted recruits. In the long term, as the nuclei expand and merge, savanna specialists tend to disappear and the savanna turns into a low-diversity forest. 5. Synthesis and applications: Fire suppression has allowed the nucleation process and consequently the woody encroachment and fast replacement of savanna specialists by forest species in the Cerrado. By elucidating the mechanisms behind woody encroachment, we recommend using prescribed fires to burn forest seedlings and to reduce tree canopy size wherever the management goal is to maintain the typical savanna structure and composition.

opencc-zeroAug 2021View details →

dryad32/100

High-intensity fires may have limited medium-term effectiveness for reversing woody plant encroachment in an African savanna

1. Woody thickening or "bush encroachment" is a growing concern in savannas worldwide and can reportedly be reversed by applying high-intensity fires. Preliminary findings following experimental fires in 2010 and 2013 indicated that woody plant cover declined one year after high-intensity fires, but increased after low-intensity fires. However, the longer-term outcomes of high-intensity fires are largely unknown. 2. To establish longer-term outcomes, we re-assessed sites subjected to Low, Medium and High-intensity fire treatments 10 years after the initial experimental fires. We compared woody vegetation structure in 2010 with that in 2020 using both ground surveys and airborne LiDAR. 3. Ground surveys revealed increases in the number of stems and individual shrubs (< 10 m tall) over 10 years, and decreases in shrub height, with no significant differences between treatments. Large trees (≥ 10 m) declined by about 65% in number due to ongoing high mortality across treatments over 10 years. 4. LiDAR surveys revealed significant but very small differences in woody plant height and cover between treatments after 10 years. Median height was around 2 m in all treatments, and 90th percentile tree height was moderately taller in the Low fire treatment. Mean canopy cover was about 55% in all treatments. The treatments, therefore, did not result in a meaningful reversal of woody encroachment with no discernible difference between the treatment sites after 10 years. 5. Synthesis and applications. The application of high-intensity fires did not reverse woody encroachment in the longer term. In addition, the application of such treatments would be impractical at a large scale. Within a framework of Strategic Adaptive Management, the next logical step would be to attempt a different approach. In this case, it is intended to use early or late wet season burns to increase the mortality of shrubs when they are in a more vulnerable phenological state. This study illustrates the importance of ongoing long-term monitoring, review and adaptation for finding practical ways to achieve desired ecological outcomes.

opencc-zeroJan 2023View details →

dryad32/100