Past human‐induced ecological legacies as a driver of modern Amazonian resilience

Read the free Plain Language Summary for this article on Journal blog. The Holocene, last 11,700 years, has been a period of accelerating human impacts every continent (Ellis et al., 2021). In Africa, Australia, Europe and Americas role humans, often in concert with rapid climate change, is clear extinction Pleistocene megafauna (Barnosky 2004; Martin, 1984; Van Der Kaars 2017). While it not known whether were ecosystem engineers, humans were. Human arrival was accompanied by altered fire regimes, biogeochemical cycling seed nutrient dispersal across landscape (Malhi 2016). ecological trajectories activities during subset more recent influences identified as being potentially important: legacies (Chazdon, 2003; Turner, 2010) that could increase forest resilience to change. These include changing soil modifications, species introductions extinctions, cultivation agricultural practices, urbanization homogenization landscape, enrichment or depletion preferred nonpreferred plant (e.g. Glaser & Woods, Lehman Lewis Maslin, 2015; Ruddiman, 2005, 2013). long-term modification ecosystems widely accepted Europe, Asia, Africa once considered have experienced lighter footprint until European colonists Meggers, 1971). Recent syntheses archaeological data South America documented people also spread throughout frequency sites increased significantly beginning around 5000 years ago (Goldberg density markedly after mid which interpreted indicate change from logistic exponential population growth development complex societies, investments construction causeways, raised islands, aqueducts ditches (Dillehay, 2000; Dillehay 2005; Erickson, Heckenberger 2008) showed populations grew they commonly switched hunter-gatherer sedentary lifestyles It now Amazonia similarly occupied modified millennia Clement 2000, 2006; 2008; Oliver, Roosevelt, 1991), database containing over 6000 recently become available (Lombardo 2018). Over 3000 Amazonia, there significant containing: (i) archaeobotanical evidence Hilbert 2017; Lombardo 2020; Piperno, 2011; Piperno Pearsall, 1998), (ii) earthwork formations 1991, 2013; Saunaluoma, 2010; Saunaluoma Schaan, 2012; Schaan 2012), (iii) formation anthropic soils (Amazonian Dark Earths, ADE), contain large amounts charcoal (indicating burning) higher levels than typical Amazonian Birk, 2003) (iv) fragments recovered terrestrial lake sediments Gosling 2021; Hammond McMichael Bush, 2019; Power Sanford 1985; Urrego Charcoal are activity closed canopy forests rarely spreads natural ignitions because everwet conditions (Bush Malhi 2009; Uhl Kauffman, 1990). Although interdisciplinary palaeoecological datasets unanimously fire, cultural complexity several millennia, these patterns uniformly intense vastness (Heckenberger Neves, Nascimento 2022; Riris Arroyo-Kalin, 2019). areas prior ca. AD 1541 (hereafter pre-European period), abundances plants through processes direct indirect Åkesson Clement, 1988; Levis 2017, Many long-lived fruit nut producing trees, such Brazil Bertholletia excelsa, planted period, maintained elevated today near those past occupation Scoles Gribel, Shepard Ramirez, Thomas 2015). Palms one most used Bernal 2011) abundant (ter Steege 2013) groups within Amazonia. palms domesticated, some regions directly enriched planting peach palm, Bactris gasipaes; e.g. Contrastingly, Iriartea deltoidea, palm primarily materials, signs both (Åkesson I. deltoidea western decrease at intensive land use periods peak intermittently less intensively Bush McMichael, After abandonment, however, persisted hundreds 1541, Francisco Orellana led first Europeans down Amazon River sparse extreme but much denser, vibrant central eastern (Medina, 1934). Jesuit missions many 1600s (Reeve, 1994), 1800s lamenting falling Indigenous populations. Indeed, crashed result disease conflict Europeans, occupied, cultivated times abandoned (Dobyns, 1966; Dull Loughlin 2018; Nevle Bird, 2008). Non-Indigenous swelled slowly Rubber Boom (1850–1920), brought an disturbance Hecht Cockburn, 1989; Weinstein, 1983). For 40 lowland had global monopoly rubber, essential commodity industrial revolution mechanization industry, transportation agriculture. Urbanization began Large cities established (i.e. Manaus, Iquitos, Porto Velho), converted plantations clear-cut provide wood fuel steam engines (Hecht, To break monopoly, 1876, seeds rubber tree Hevea brasiliensis smuggled England, cultivated, sent Malaysia where 1890s Coomes Barham, 1994; Drabble, 1973). World prices eventually fell 1920s boom collapsed, leading another wave abandonment (Coomes Ecological can centuries tropical due long lifespans Chazdon, 2003). human-induced deforestation, occurred influence composition functional traits modern (Feldpausch Iriarte Maezumi, Alves, 2022). We hypothesize shifts may resilience, function resistance (the capacity resist disturbance) recovery (rate return functions following drought events (sensu Hodgson Forest shaped climatic, edaphic hydraulic gradients, habitat heterogeneity regional scales (Costa Killeen Solorzano, Oliveira 2019), we likely local (Figure 1). general successional changes disturbances rainforests, variability. shape legacy direction magnitude compared predisturbed state) dependent multiple factors. type disturbance, timing recurrence all factors will affect resulting how persists landscape. Based factors, expect post-European be different based pre-Columbian activity. Soil modifications leave persistent legacy. Archaeologists uncovered anthropogenic soils, called terras pretas formed thousands (Glaser Terras located along rivers parts basin 2004). availability (Lehman growing atop high certain plants, differing adjacent non-terra preta (de Junqueira 2010). communities differ (on soils) point detectable using satellite-based metrics (Palace Thayn 2011). Successional pathways deforestation depend intensity management (Jakovac Mesquita 2001; 1988). example, cleared short-term results succession dominated Cecropia species, whereas cattle pastures pathway Vismia (Mesquita 2001). Early Cecropia-dominated able regain richness faster pasture (Vismia-dominated), remain poor least 25 colonization limited, size deforested area distance nearest intact forest; pattern found systems (Banin 2023; Sezen 2007; White Deforestation reduces organic matter, physical properties soil, affects alters microbial Aide Cavelier, Borneman Triplett, 1997; Kroeger Melo Collectively, studies suggest mechanized era left nonmechanized clearing era. Fire regimes determine strength, legacies. Fire, particularly fires, repeated burning induce larger practices fire-free slash mulch practices). transformative agent no evolutionary adaptations (Uhl A single burn cause turnover burns complete replacement (Barlow Peres, Once either becomes flammable, creating positive feedback loop leads probabilities subsequent (Nepstad 2004, Repeated site pre- eras 2021, 2016; 2021), thus time since determines fire-induced addition enrichment, domestication 2011), shapes (McMichael, At Lake Kumpaka Ecuadorian Amazon, reached its highest abundance ~500 ~700 CE, 1960s reduced them again This represented shift predisturbance state lasted 400 (Liu Colinvaux, Indirect mechanisms other recovery, including edge effects, gap dynamics, predation Cochrane, Laurance, Wyatt Silman, All would influenced waves clearance, hunting depleted frugivore Thus, typically unintentional. amount elapsed event(s) stage forest. Disturbances usually deviations distant time. part, scale deforestation. Occasionally, ‘halted’ extended competitive dominance (Paul Yavitt, Zahawi Augspurger, 1999). Vines arrest settings Paul Schnitzer Bongers, Takeshige 2023). Some early pioneer do same. An example slowing Vismia-dominated form One 40,000 km2 bamboo-dominated southwestern spatial distribution geoglyphs, (Schaan associated (Guadua spp.; 2014). Bamboo plant, when colonizes halt overloading trees putting out rhizomes prevent (Griscom Ashton, Resistance (resilience) vegetation determined Sakschewski Abiotic water-table depth, topography, moisture Köpp Hollunder Leaf area, size, trait diversity linked though always agreement Anderegg Berenguer Phillips Serra-Maluquer Plants thicker bark basal resprouting abilities resistant events, suggested fires (Pausas, Pontes-Lopes Poorter occur Chazdon 2007) (van der Sande Pioneer possess low (fast growth), short investment defensive compounds (Guariguata Ostertag, Figure 2). As mature balance towards individuals longer van Wittmann 2002; Trait expected mid-successional forests, probably lasts c. 200–400 postdisturbance, mixture varying states (Cole 2014; Foster, 1990; Within range maturing accumulate greater densities, thinner bark, leaves, height Forests even postdisturbance gain lose earlier outcompeted Given important relate potential recognizing necessarily Cadotte Gunderson, Lohbeck early- competition Chambers Cole 2016), should richer conferring ability basally resprout, past. Permanent pretas, (Junqueira 2010), suited 3a). propagated eras, immediately event, make fire-prone. favours withstand (Brando 1991). starting burned twice thrice begin future resilient traits. Pre-European resulted accumulated Increased recurrence, patch cleared) overall loss comes Panamá. On Gigante Peninsula (Panamá), widespread 600 Oenocarpus mapora survived (McMichael resprout base, expand clonally, allowing successfully recruit mortality (De Steven, 1989). O. alter outcompete Farris-Lopez 2004), combined relatively lifespan (100–200 years; Richard Condit personal communication), years. Examples (in eras) come Mauritia flexuosa deltoidea. fruits flavourful nutritious flesh nurtured peoples M. thick ground reproductive plasticity survive (Arneaud Consequently, set promote release killed competitors unscathed (Rull Montoya, Near monodominant stands appear components swampy areas, active discussion product hydrarch successions habitats manufactured (Junk, Montoya Rull, Rull tends selectively removed (Bernal fire-sensitive rebounds 100–200 Regardless reason enhanced palms, their presence confer resistance, substantial dessication (Sousa 2020). excelsa large-seeded nonpalm prized nuts (Brazil nuts) (Clement B. relates suggesting persistence (Thomas large, fast-growing common secondary (Peña-Claros 2002). shown drought, deep root system physiological (Schimpl There distinction resilience. 100 years), urbanization, 3). Modern extensive occurring Observational disturbed vulnerable resilient) undisturbed ones (Berenguer traits, rapidly earliest stages succession. very taxa create dense canopies hence cool moist microclimates reduce risk Ray 2005). Instead, woodlands dry, rich (Cochrane, Figures 2 They slow additional only matures, leaf index, increase, cool, shaded going succession, sufficient acquire urbanized landscapes unlikely future. Urbanized properties, defaunated lack surrounding matrix propagules recolonization (Sezen 2007). instead ‘sweet spot’ intermediate hypothesis mechanism proposed explain biodiversity (Connell, 1978). variant maintenance localized scales. predict mid-intensity 200–600 show strongest speediest highly diverse determining efforts (Heijink 2020, 2022), crucial understanding extent 3b). phosphorus calcium) increasing up 4 km (Levis lived river bluffs (Denevan, 1996). Most terra opening 10 Evidence decay away Hunting, abundances, extends 8–10 settlement (Levi 2000). farther intensive. Estimates derived remote sensing field-collected 4). Measurements remotely sensed (or thereof) given pixel rate recover megadroughts 2010, 2015/6; Saatchi Yang Normalized Differential Vegetation Index (NDVI), index developed 1970s (Rouse 1974), estimate Verbesselt limitations seasonal variability optical depth (VOD) complement (Boulton limited penetration microwaves sensitive water content (Papastefanou 27 too detect fine patterns. Surface reflectance characterize changes, chemical (Gutman Pinheiro Satellite-based (including radiative power) postfire (Lizundia-Loiola botanical surveys record 4), plots repeatedly surveyed capture carbon dynamics (Anderson-Teixeira ForestPlots.net Lopez-Gonzalez 2009). estimated sites. Field-based research abiotic biotic type, hydrological groundwater), fertility, activity, Costa Flores Holmgren, Sousa Sullivan field-based estimates data, two align (Flores mismatch methodologies measurement, believe local-scale state. Unpiloted aerial (UASs, drones) valuable, cost-effective platform bridges measurement