Pollen-vegetation relationships along steep climatic gradients in western Amazonia

Abstract

Question: How accurately do Amazonian montane forest pollen spectra reflect the vegetation? Can compositional changes observed in the vegetation along environmental gradients be identified in the pollen spectra? How well do herbarium collection data and bioclimatic envelopes represent abundance changes along elevation gradients? Location: Amazonian montane forests, Peru. Methods: Moss polsters collected along five altitudinal transects spanning over 3000 m a.s.l. were used to characterize pollen spectra. Vegetation plot data from a network of 15 1‐ha permanent plots were used to correlate pollen spectra with present‐day vegetation. Probability density functions (PDFs) fitted to pollen and plot data allowed comparisons using Spearman correlation coefficients. Ordination analyses were used to summarize changes in pollen spectra. Correlations between pollen‐based PDFs and previously‐published herbarium collection PDFs were also evaluated. Results: Pollen spectra closely reflected changes in species composition along elevation gradients. A mid‐elevation shift in pollen spectra was identified using ordination analyses. Pollen spectra from the driest forest in our data set were statistically different from those of wet forests. Pollen abundance PDFs along the altitudinal gradient were significantly correlated (P<0.01) with PDFs fitted to plot abundance, basal area and herbarium collection data for ten out of 11 taxa analysed. Conclusions: Pollen spectra closely reflected the vegetation composition of Amazonian montane forests. The differentiation of pollen spectra from dry localities showed the potential of genus‐level pollen data to reflect precipitation gradients. Pollen spectra also reflected mid‐elevation compositional changes well along the lower elevation limit of ground cloud formation. Despite collection biases, herbarium‐based bioclimatic envelope PDFs also represented well forest compositional changes along elevation gradients.

The influence of abrupt climate change on the ice‐age vegetation of the Central American lowlands

“…, 2011). At the individual pollen taxon level, it is difficult to establish relationships that could lead to the estimation of individual species abundances (Bush & Rivera, 1998; Urrego et al. , 2011).…”

Detrended correspondence analysis: A useful tool to quantify ecological changes from fossil data sets

“…Subsequently, pollen is submitted to differential preservation and degradation processes, causing further preservation bias. However, it has been demonstrated for diverse locations in the world that although imperfect, pollen spectra are feasible tools to identify vegetation patterns associated with biogeographic and environmental gradients at micro to macro scales, mostly depending on the particular environmental settings (Bush, 1991(Bush, , 1995Rodgers and Horn, 1996;Bonnefille et al, 1999;CorreaMetrio et al, 2011a;Urrego et al, 2011). Thus, pollen and spore signals offer proxies for vegetation diversity and reflect latitudinal, altitudinal, and other gradients associated with community composition and structure.…”

Investigación y conservación de la biodiversidad en Perú: importancia del uso de técnicas modernas y procedimientos administrativos eficientes

“…estudios de palinología y paleoecología; Urrego et al 2005Urrego et al , 2011, y que los procedimientos administrativos sean simplificados y agilizados para optimizar el estudio de la biodiversidad del Perú.…”