Soil erosion as a resilience drain in disturbed tropical forests
Tropical forests are threatened by intensifying natural and anthropogenic disturbance regimes. Disturbances reduce tree cover and leave the organic topsoil vulnerable to erosion processes, but when resources are still abundant forests usually recover.
Across the tropics, variation in rainfall erosivity – a measure of potential soil exposure to water erosion – indicates that soils in the wetter regions would experience high erosion rates if they were not protected by tree cover. However, twenty-first-century global land cover data reveal that in wet South America tropical tree cover is decreasing and bare soil area is increasing. Here we address the role of soil erosion in a positive feedback mechanism that may persistently alter the functioning of disturbed tropical forests.
Based on an extensive literature review, we propose a conceptual model in which soil erosion reinforces disturbance effects on tropical forests, reducing their resilience with time and increasing their likelihood of being trapped in an alternative vegetation state that is persistently vulnerable to erosion. We present supporting field evidence from two distinct forests in central Amazonia that have been repeatedly disturbed. Overall, the strength of the erosion feedback depends on disturbance types and regimes, as well as on local environmental conditions, such as topography, flooding, and soil fertility. As disturbances intensify in tropical landscapes, we argue that the erosion feedback may help to explain why certain forests persist in a degraded state and often undergo critical functional shifts.
KeywordsDynamics Ecosystem services Feedback Forest restoration Global change Secondary forests
We thank Carolina Levis and Marten Scheffer for constructive comments, and four anonymous reviewers for their criticism and suggestions that helped improve this manuscript. B.M.F. is funded by São Paulo Research Foundation Grant FAPESP 2016/25086-3.
- Berenguer E, Gardner TA, Ferreira J, Aragão LEOC, Mac Nally R, Thomson JR, Vieira ICG, Barlow J (2018) Seeing the woods through the saplings: using wood density to assess the recovery of human-modified Amazonian forests. J Ecol 106:2190–2203. https://doi.org/10.1111/1365-2745.12991 CrossRefGoogle Scholar
- Borrelli P, Robinson DA, Fleischer LR, Lugato E, Ballabio C, Alewell C, Meusburger K, Modugno S, Schütt B, Ferro V, Bagarello V, Oost KV, Montanarella L, Panagos P (2017) An assessment of the global impact of 21st century land use change on soil erosion. Nat Commun 8:2013CrossRefPubMedPubMedCentralGoogle Scholar
- Chazdon RL (2014) Second growth: the promise of tropical forest regeneration in an age of deforestation University of Chicago PressGoogle Scholar
- DeAngelis DL, Post WM, Travis CC (1986) Positive feedback in natural systems. Springer, BerlinGoogle Scholar
- DiMiceli CM, Carroll ML, Sohlberg RA, Huang C, Hansen MC (2011) Annual global automated MODIS vegetation continuous fields (MOD44B) at 250 m spatial resolution for data years beginning day 65, 2000–2010, collection 5 percent tree cover. Univ of Maryland, College Park, MDGoogle Scholar
- Douglas I, Bidin K, Balamurugan G, Chappell NA, Walsh RPD, Greer T, Sinun W (1999) The role of extreme events in the impacts of selective tropical forestry on erosion during harvesting and recovery phases at Danum Valley, Sabah. Philosophical Transactions of the Royal Society B: Biological Sciences 354:1749–1761CrossRefGoogle Scholar
- El-Swaify SA, Dangler EW, Armstrong CL (1982) Soil erosion by water in the tropics. Hawaii Institute of Tropical Agriculture and Human Resources (USA)Google Scholar
- Fearnside PM (1980) The prediction of soil erosion losses under various land uses in the Transamazon highway colonization area of Brazil. Tropical Ecology and Development Part 2:1287–1295Google Scholar
- Goldammer JG (1990) Fire in the tropical biota. In symposium on fire ecology 1989: Freiburg University) springer-VerlagGoogle Scholar
- Heyligers PC (1963) Vegetation and soil of a white-sand savanna in Suriname NV Noord-Hollandsche Uitgevers Maatschappij 1-148Google Scholar
- Lal R, Elliot W (1994) Erodibility and erosivity. Soil erosion research methods 1:181–208Google Scholar
- Lowdermilk WC (1953) Conquest of the land through seven thousand years. US Government Printing Office, WashingtonGoogle Scholar
- Martinelli LA, Piccolo MC, Townsend AR, Vitousek PM, Cuevas E, McDowell W, Robertson GP, Santos OC, Treseder K (1999) Nitrogen stable isotopic composition of leaves and soil: tropical versus temperate forests. Biogeochemistry 46:45–65Google Scholar
- Millennium Ecosystem Assessment 2005 Ecosystems and Human Well-being: Synthesis Island Press, Washington, DCGoogle Scholar
- Olson GW (1981) Archaeology: lessons on future soil use. J Soil Water Conserv 36:261–264Google Scholar
- Quesada CA, Phillips OL, Schwarz M, Czimczik CI, Baker TR, Patiño S, Fyllas NM, Hodnett MG, Herrera R, Almeida S, Alvarez Dávila E, Arneth A, Arroyo L, Chao KJ, Dezzeo N, Erwin T, di Fiore A, Higuchi N, Honorio Coronado E, Jimenez EM, Killeen T, Lezama AT, Lloyd G, López-González G, Luizão FJ, Malhi Y, Monteagudo A, Neill DA, Núñez Vargas P, Paiva R, Peacock J, Peñuela MC, Peña Cruz A, Pitman N, Priante Filho N, Prieto A, Ramírez H, Rudas A, Salomão R, Santos AJB, Schmerler J, Silva N, Silveira M, Vásquez R, Vieira I, Terborgh J, Lloyd J (2012) Basin-wide variations in Amazon forest structure and function are mediated by both soils and climate. Biogeosciences 9:2203–2246CrossRefGoogle Scholar
- Rowland L, da Costa ACL, Galbraith DR, Oliveira RS, Binks OJ, Oliveira AA, Pullen AM, Doughty CE, Metcalfe DB, Vasconcelos SS, Ferreira LV, Malhi Y, Grace J, Mencuccini M, Meir P (2015) Death from drought in tropical forests is triggered by hydraulics not carbon starvation. Nature 528:119–122CrossRefPubMedGoogle Scholar
- Silva LC, Hoffmann WA, Rossatto DR, Haridasan M, Franco AC, Horwath WR (2013) Can savannas become forests? A coupled analysis of nutrient stocks and fire thresholds in central Brazil Plant and Soil 373:829–842Google Scholar
- Silvério DV, Brando PM, Balch JK et al (2013) Testing the Amazon savannization hypothesis: fire effects on invasion of a neotropical forest by native cerrado and exotic pasture grasses. Philosophical transactions of the Royal Society of London B: Biological sciences 368:20120427CrossRefPubMedGoogle Scholar
- Staal A, Flores BM (2015) Sharp ecotones spark sharp ideas: comment on " Structural, physiognomic and above-ground biomass variation in savanna–forest transition zones on three continents–how different are co-occurring savanna and forest formations?" by Veenendaal et al (2015). Biogeosciences 12:5563–5566.Google Scholar
- Tomasella J, Vieira RMSP, Barbosa AA et al (2018) Desertification trends in the Northeast of Brazil over the period 2000–2016 International Journal of Applied Earth Observation and Geoinformation 73:197–206Google Scholar
- Veenendaal EM, Torello-Raventos M, Feldpausch TR, Domingues TF, Gerard F, Schrodt F, Saiz G, Quesada CA, Djagbletey G, Ford A, Kemp J, Marimon BS, Marimon-Junior BH, Lenza E, Ratter JA, Maracahipes L, Sasaki D, Sonké B, Zapfack L, Villarroel D, Schwarz M, Yoko Ishida F, Gilpin M, Nardoto GB, Affum-Baffoe K, Arroyo L, Bloomfield K, Ceca G, Compaore H, Davies K, Diallo A, Fyllas NM, Gignoux J, Hien F, Johnson M, Mougin E, Hiernaux P, Killeen T, Metcalfe D, Miranda HS, Steininger M, Sykora K, Bird MI, Grace J, Lewis S, Phillips OL, Lloyd J (2015) Structural, physiognomic and above-ground biomass variation in savanna-forest transition zones on three continents-how different are co-occurring savanna and forest formations? Biogeosciences 12:2927–2951CrossRefGoogle Scholar
- Wright IJ, Reich PB, Westoby M, Ackerly DD, Baruch Z, Bongers F, Cavender-Bares J, Chapin T, Cornelissen JHC, Diemer M, Flexas J, Garnier E, Groom PK, Gulias J, Hikosaka K, Lamont BB, Lee T, Lee W, Lusk C, Midgley JJ, Navas ML, Niinemets Ü, Oleksyn J, Osada N, Poorter H, Poot P, Prior L, Pyankov VI, Roumet C, Thomas SC, Tjoelker MG, Veneklaas EJ, Villar R (2004) The worldwide leaf economics spectrum. Nature 428:821–827CrossRefPubMedPubMedCentralGoogle Scholar