Widespread forest-savanna coexistence but limited bistability at a landscape scale in Central Africa DOI Creative Commons

A. G. van der Zwaan,

Arie Staal, Mariska te Beest

и другие.

Environmental Research Letters, Год журнала: 2024, Номер 19(12), С. 124035 - 124035

Опубликована: Окт. 30, 2024

Abstract Tropical forest and savanna frequently coexist under the same climatic conditions, which has led to hypothesis that they could represent alternative ecosystem states, stabilized by internal feedbacks. An implication of this is may be bistable exhibit tipping behavior in response changing conditions. However, we pose local presence within coexistence landscapes not sufficient evidence these are stable states at larger scales. Therefore, explore forest-savanna bistability landscape scale Central Africa. Using remote sensing data on tree cover, classify 0.1° × (approx. 10 km) as homogeneous forest, savanna, or coexistence, analyze roles climate, topography soil sand content driving their distributions. We find common occurs for whole range mean annual precipitation our study area. At low precipitation, however, increases with topographic roughness therefore likely driven redistribution resources rather than Coexistence intermediate high remains unexplained studied variables, caused either heterogeneity unmeasured drivers feedback-driven bistability. scale, ranges occur have only limited overlap, overlap can largely explained other external drivers, such seasonality, content, topography. This lack Africa means transitions between them mostly local, resulting states. conclude likelihood large-scale ecosystems lower previously thought.

Язык: Английский

Arctic tundra ecosystems under fire—Alternative ecosystem states in a changing climate? DOI Creative Commons
Ramona Julia Heim, Adrian V. Rocha, Vitalii Zemlianskii

и другие.

Journal of Ecology, Год журнала: 2025, Номер unknown

Опубликована: Март 13, 2025

Abstract Climate change is expected to induce shifts in the composition, structure and functioning of Arctic tundra ecosystems. Increases frequency severity fires have potential catalyse vegetation transitions with far‐reaching local, regional global consequences. We propose that post‐fire recovery, coupled climate change, may not necessarily lead pre‐fire conditions. Our hypothesis, based on surveys literature, suggests two climate–fire driven trajectories. One trajectory results increased woody under low fire frequency; other grass dominance high frequency. Future research should address uncertainties regarding possible ecosystem linked fires, using methods encompass greater temporal spatial scales than previously addressed. More case studies, especially underrepresented regions types, are essential broaden empirical basis for forecasts management strategies. Synthesis . review synthesises current knowledge trajectories ecosystems, highlighting alternative states their implications. discuss challenges defining predicting these as well future directions.

Язык: Английский

Процитировано

0
Patterns and Drivers of Phylogenetic Beta Diversity in the Forests and Savannas of Africa DOI Creative Commons
Mathew Rees, Adeline Fayolle, John L. Godlee

и другие.

Journal of Biogeography, Год журнала: 2025, Номер unknown

Опубликована: Апрель 7, 2025

ABSTRACT Aim Studying beta diversity, or the variation in species composition among communities, can give insights into plant community assembly over space and time. If different biomes show contrasting large‐scale beta‐diversity patterns, this indicate divergent evolutionary histories ecological processes that then drive turnover communities. Here, we examine phylogenetic patterns across Africa forest savanna assemblages, two most widespread tropical on continent. We hypothesise savannas will lower diversity due to their younger history. Location Tropical Africa. Taxon Woody angiosperms. Methods gathered 301,159 occurrences of woody angiosperms representing 1883 1302 species. compared levels between analysed spatial using 1° grid cells modelled relationship with climate, disturbance geographical distance. Results found greater relative regional whereas assemblages local diversity. The distribution showed strong East–West for both forests savannas, aligned a major floristic discontinuity associated Albertine rift. Our results also highlighted West as showing high amount compositional change biomes, arranged along an aridity gradient. Variance partitioning predictors linked precipitation were main drivers but importance individual was each biome. Main Conclusions Contrary our expectations, may have deeper richer history than suggested by previous studies regions conservation value. Finally, demonstrate environmental filtering is dominant force influencing these important at continental scale.

Язык: Английский

Процитировано

0
Interactions between soil and other environmental variables modulate forest expansion and ecotone dynamics in humid savannas of Central Africa DOI Creative Commons
Le Bienfaiteur Sagang,

Imma Tcheferi,

Pierre Ploton

и другие.

Proceedings of the Royal Society B Biological Sciences, Год журнала: 2024, Номер 291(2033)

Опубликована: Окт. 1, 2024

Forest expansion into savanna is a pervasive phenomenon in West and Central Africa, warranting comparative studies under diverse environmental conditions. We collected vegetation data from the woody grassy components within 73 plots of 0.16 ha distributed along successional gradient humid to forest Africa. associated spatially collocated edaphic parameters fire frequency derived remote sensing investigate their combined influence on vegetation. Soil texture was more influential shaping structure species distribution than soil fertility, with clay-rich soils promoting higher grass productivity frequency. Savanna featuring aboveground biomass surpassing 40 Mg −1 could escape grass–fire feedback loop, by depressing below 4 . This thicker layer also favoured establishment fire-tolerant pioneers, which synergically contributed forests. Conversely, savannas this suppression threshold sustained balance between trees grasses through mechanism. hysteresis particularly pronounced clayey soils, suggests that contrast young forests might represent alternative ecosystem states, although low remained vulnerable edge encroachment.

Язык: Английский

Процитировано

1
Widespread forest-savanna coexistence but limited bistability at a landscape scale in Central Africa DOI Creative Commons

A. G. van der Zwaan,

Arie Staal, Mariska te Beest

и другие.

Environmental Research Letters, Год журнала: 2024, Номер 19(12), С. 124035 - 124035

Опубликована: Окт. 30, 2024

Abstract Tropical forest and savanna frequently coexist under the same climatic conditions, which has led to hypothesis that they could represent alternative ecosystem states, stabilized by internal feedbacks. An implication of this is may be bistable exhibit tipping behavior in response changing conditions. However, we pose local presence within coexistence landscapes not sufficient evidence these are stable states at larger scales. Therefore, explore forest-savanna bistability landscape scale Central Africa. Using remote sensing data on tree cover, classify 0.1° × (approx. 10 km) as homogeneous forest, savanna, or coexistence, analyze roles climate, topography soil sand content driving their distributions. We find common occurs for whole range mean annual precipitation our study area. At low precipitation, however, increases with topographic roughness therefore likely driven redistribution resources rather than Coexistence intermediate high remains unexplained studied variables, caused either heterogeneity unmeasured drivers feedback-driven bistability. scale, ranges occur have only limited overlap, overlap can largely explained other external drivers, such seasonality, content, topography. This lack Africa means transitions between them mostly local, resulting states. conclude likelihood large-scale ecosystems lower previously thought.

Язык: Английский

Процитировано

0