Summed radiocarbon-date distributions for the Amazonian biome fit logistic growth approaching carrying capacity in the centuries before European colonization; the proxy's terminal decline is attributed by the authors to sampling bias compounded by post-European collapse, not to a pre-European endogenous crash.

A single aggregate SPD proxy (AMZ-E020) with author-stated biases; the attribution of the terminal decline to sampling plus post-contact collapse is plausible but not independently confirmed.

Aggregate summed radiocarbon probability distributions indicate biome-wide demographic expansion halting only at European contact, pushing back against theories of a ubiquitous endogenous collapse before 1492. This supports the thesis that European-introduced disruptions, rather than ecological exhaustion, drove the demographic crash. The strongest opposing consideration is that basin-wide aggregate curves mask profound regional variances, and known localized declines (such as in parts of the Llanos de Mojos pre-1450) show that regional reorganizations did occur independently of external contact.

Arroyo-Kalin and Riris (2021) show that summed radiocarbon-date distributions over the last ~1700 years fit a logistic growth model approaching carrying capacity and argue that the terminal decline reflects sampling biases plus post-contact collapse. This supports the claim that the proxy does not indicate a pre-contact endogenous crash at biome scale. However, SPDs are coarse proxies with known biases, and regional trajectories can diverge from the aggregate, which means the inference about demographic dynamics remains tentative and best graded as provisional.

AMZ-E020 reports that summed radiocarbon dates over the 1,700 years before colonization fit logistic growth toward carrying capacity, with the terminal proxy decline attributed to sampling bias compounded by post-European collapse and dispersal rather than a pre-contact endogenous crash. That is one aggregate SPD study, explicitly a relative-change proxy, not a census. Strongest opposing consideration: regional signals can diverge from the biome curve — agricultural decline in parts of the Llanos de Mojos beginning AD 1300–1450 is the named counterexample — so the aggregate does not preclude regional pre-contact reorganization.

Arroyo-Kalin & Riris 2021, verified verbatim, find biome-wide radiocarbon proxies fitting logistic growth toward carrying capacity up to European arrival, with the terminal decline attributed to sampling bias compounded by post-contact collapse. That bears directly on whether the disappearance requires a pre-contact endogenous crash — at aggregate level, this record says no. The strongest opposing consideration is that SPDs are proxies with stated biases, this is a single study, and regional signals can diverge from the aggregate: parts of the Llanos de Mojos show agricultural contraction beginning AD 1300–1450, before contact. One proxy study cannot settle a basin-wide demographic question, so provisional support with moderate confidence is the honest grade.

One study, one proxy class: summed radiocarbon distributions fitting a logistic curve toward carrying capacity, with the terminal decline attributed by the authors to sampling bias compounded by post-contact collapse (AMZ-E020). SPDs are known to be sensitive to taphonomy, calibration-curve artifacts and research intensity, and the authors' own caveats say they proxy relative change only. The attribution of the terminal downturn to bias plus post-contact effects rather than pre-contact decline is an interpretation the same data could not easily distinguish from a genuine late fall. The strongest opposing consideration is regional divergence: parts of the Llanos de Mojos show agricultural decline from AD 1300–1450, so the biome aggregate can conceal real pre-contact reorganization.

Single aggregate proxy study with stated biases; regional counterexamples exist.

Single aggregate proxy with stated biases (AMZ-E020); nothing new bears on it.

Verified verbatim from Arroyo-Kalin & Riris 2021, including their own caveats: SPDs are "proxies for relative population change" — an aggregate signal with stated biases, not a census (the "not a census" phrasing is this case's paraphrase of those caveats).

Arroyo-Kalin and Riris (2021) analyzed biome-wide summed radiocarbon probability distributions (SPDs) and found that pre-Columbian population growth over 1,700 years closely conformed to a logistic growth model approaching regional carrying capacity prior to European contact. They explicitly demonstrated that the terminal drop in the radiocarbon curve is an artifact of archaeological sampling biases intertwined with post-contact demographic collapse, rather than an endogenous pre-Columbian crash. The strongest opposing consideration is that summed radiocarbon probabilities are imperfect proxies for absolute census dynamics and can be distorted by regional excavation imbalances and taphonomic decay.

The logistic-growth fit and the attribution of the terminal proxy decline to sampling bias compounded by post-European collapse are verified verbatim from Arroyo-Kalin & Riris 2021. Strongest opposing consideration: summed radiocarbon distributions are aggregate proxies with acknowledged taphonomic and sampling biases, and "carrying capacity" is model-relative — the result constrains relative trajectory, not census-scale totals.

AMZ-E020 reports that the basin-wide summed-radiocarbon proxy fits logistic growth over the 1,700 years before colonization and was interpreted as approaching carrying capacity. It also directly gives the authors' sampling-bias-plus-collapse explanation for the terminal decline. The strongest opposing consideration is that summed date distributions are biased proxies for relative demographic change, not direct population measurements or proof of a unique logistic mechanism.

Arroyo-Kalin & Riris 2021 (AMZ-E020) find summed radiocarbon distributions fit logistic growth toward carrying capacity before colonization, attributing terminal decline to sampling bias plus post-European collapse rather than a pre-European crash. SPDs are relative proxies with stated biases, so confidence stays moderate.

AMZ-E020 verifies the logistic fit over 1,700 years and the authors' carrying-capacity inference, plus their attribution of the terminal decline to sampling bias compounded by post-contact collapse and dispersal. But summed radiocarbon probability distributions are relative-population proxies with well-known taphonomic, calibration, and research-agenda biases, and the record's own limitation says so; a logistic shape is also exactly what accumulating, decay-biased date inventories can produce artefactually. Critically, the attribution of the terminal downturn to bias-plus-post-European-collapse rather than an endogenous pre-contact crash is an interpretive choice made by the same authors whose model supplies the growth curve, with no independent test in this ledger. I weight this claim lightly and note that my scepticism about SPD inference draws on general methodological background as well as the record itself.

AMZ-E020 quotes the logistic fit over 1,700 years and the authors' attribution of the terminal decline to sampling bias compounded by post-contact collapse. Summed radiocarbon distributions are proxies for relative change with stated biases; the only record for this claim is moderate strength.

E020 (moderate) quotes the logistic fit over 1,700 years and the authors' attribution of the terminal decline to sampling bias compounded by post-contact collapse. Summed radiocarbon distributions proxy relative change with stated biases.

E020 (moderate) supports logistic growth toward carrying capacity with the authors' own caveats that the proxy is aggregate and biased.

AMZ-E020 (moderate, supports) quotes the logistic fit over 1,700 years before colonization, the carrying-capacity inference 'however high', and the attribution of the terminal decline to sampling bias compounded by post-contact collapse. Summed date distributions are relative proxies with stated biases.

Summed radiocarbon probability distributions across the Amazon biome fit a logistic demographic growth curve approaching carrying capacity in the centuries immediately preceding colonization, with terminal drops reflecting sampling biases and post-contact collapse rather than pre-contact decline (Arroyo-Kalin & Riris 2021). Strongest opposing consideration: Summed radiocarbon dates are aggregate proxies heavily distorted by taphonomic loss and modern archaeological discovery biases, representing relative activity rather than absolute population counts.

AMZ-E020 verifies the logistic-growth fit and the authors' attribution of the terminal decline to sampling bias plus post-European collapse. The strongest opposing consideration: SPDs are aggregate proxies with documented taphonomic and sampling biases, and the terminal-decline attribution is the authors' interpretation, not an independent measurement — the fit's carrying-capacity reading should not be spent as a census.

AMZ-E020 reports that the summed radiocarbon proxy fits logistic growth over the 1,700 years before colonization and that the authors attribute its terminal decline to sampling bias compounded by colonial-era decline and dispersal. This supports the claim as a description of the published model and interpretation. The strongest opposing consideration is that summed radiocarbon distributions are biased relative-population proxies, not direct demographic measurements or proof of carrying capacity.

Arroyo-Kalin & Riris 2021 report logistic growth toward carrying capacity over ~1700 years before colonization and attribute terminal SPD decline to sampling bias compounded by post-European collapse and dispersal (AMZ-E020). SPDs are relative proxies with stated biases, not censuses; the directional demographic reading is adequately supported at aggregate level.

AMZ-E020 quotes the logistic-fit result and the authors' attribution of the terminal decline to sampling bias compounded by post-European collapse. The claim is carefully scoped to what the authors found and how they interpret it, which the record establishes. The substantive weakness is inherent to the method: summed probability distributions are relative-population proxies with well-known taphonomic and calibration artefacts, and the attribution of the terminal downturn to bias rather than an endogenous pre-contact crash is an interpretive choice that the proxy itself cannot adjudicate.

Arroyo-Kalin and Riris (2021) demonstrate that summed radiocarbon probability distributions across Amazonia match a logistic growth model reaching carrying capacity prior to European contact, interpreting the terminal drop-off as taphonomic sampling bias combined with colonial collapse. The strongest opposing consideration is that summed probability distributions are widely recognized as susceptible to major research and discovery biases, blurring true demographic trajectories.

The claim accurately reports what Arroyo-Kalin & Riris found and, importantly, attributes the terminal decline to sampling bias plus collapse rather than endogenous crash. The opposing consideration is inherent to the method: summed radiocarbon distributions are proxies with taphonomic and sampling biases the authors themselves state, so the logistic-fit result is an aggregate suggestion, not a demographic measurement.

AMZ-E020 reports that the summed radiocarbon proxy fit logistic growth toward carrying capacity and that the authors attributed its terminal decline to sampling bias compounded by post-contact decline and dispersal. The strongest opposing consideration is that summed radiocarbon distributions are biased proxies rather than censuses, and the causal interpretation of the terminal pattern is not directly measured. The claim accurately describes a supported model result without establishing a unique demographic history.

Arroyo-Kalin & Riris (E020) show summed-probability distributions fitting logistic growth to carrying capacity, with terminal decline attributed to sampling bias plus post-contact collapse. Strongest opposing consideration is that SPDs remain relative proxies with acknowledged biases, not absolute censuses.

E020 quotes the authors directly. Growth over the 1,700 years before colonization 'adheres to a logistic model', and populations 'had potentially reached carrying capacity (however high)'. The terminal decline 'is likely to be an outcome of archaeological sampling biases, compounded by demographic decline and dispersal as Europeans enter the region'. The claim reports this accurately and marks the attribution as the authors'. The strongest opposing consideration is methodological: summed distributions are proxies sensitive to research intensity, preservation, and calibration (E020 limitation). The proxy cannot itself separate a late pre-contact downturn from sampling artefact, so the attribution is interpretation, not measurement.

AMZ-E020 reports that summed radiocarbon dates over 1,700 years fit logistic growth. The authors attribute the terminal decline to sampling bias compounded by colonial decline, and the claim describes this result accurately. But summed dates are relative proxies with taphonomic and discovery biases, and 'carrying capacity (however high)' fixes no level.