Fine-Scale Plant Richness Mapping of the Andean Páramo According to Macroclimate

Abstract

Understanding the main relationships between the current macroclimate and broad spatial patterns of plant diversity is a priority in biogeography, and although there is an important body of studies on the topic worldwide, tropical mountains remain underrepresented. Because understanding primary drivers of diversity patterns in the Andean páramo is still in its infancy, we focused on evaluating the role of the current macroclimate in form of three complementary hypotheses, energy, seasonality and harshness, in explaining local variation of plant species richness. We relied on 1,559 vegetation plots that offered a fine-scale outlook on real species assemblages due to community rules and species' interactions with their surrounding environment, including climate. Generalized Least Squares (GLS) regression models provided insight on the significance of the different hypotheses in explaining local plant richness, but only the energy and seasonality hypotheses received partial support. The best model was then combined with spatial interpolation Kriging modeling techniques to project species richness for a standardized 25 m 2 plot throughout the entire páramo biogeographical province. We highlighted a North-South increase in richness with several species-rich areas, potential local biodiversity hotspots, independent of the general gradient: the Amotape-Huancabamba zone, Sangay and Cotacachi areas, and eastern Venezuelan Andes. Our endeavor to finely map local richness is the first effort predicting macroecological patterns in the emblematic Andean páramo and contributes novel biogeographical knowledge useful to further support in-depth research and conservation focus in the northern Andes.

The fate of páramo plant assemblages in the sky islands of the northern Andes

“…Overall, we found no support for the negative relationship hypothesis between actual richness and future richness changes, as the eastern Ecuadorian mountains, known as very diverse locally (although so expressed at a smaller local scale than the pixel, i.e. the vegetation plot), suffered less drastic changes than the less diverse northern mountains (Peyre et al, 2019). Because this finding plausibly supposes that the communities' richness capacity is not reached on these sky islands, we recommend further scientific focus on that particular macroecological hypothesis.…”

“…Multicollinearity between variables was evaluated using a variance inflation factor correlation analysis ( vif function in the usdm R package; Naimi et al , 2014), and all variables below a threshold value of 0.7 for the Pearson correlation coefficient were retained (Dormann et al , 2013), resulting in the following selection: mean diurnal temperature range (bio2); temperature seasonality (bio4); mean temperature of the wettest quarter (bio8); precipitation seasonality (bio15); and precipitation of the coldest quarter (bio19). This set of predictors was not fitted per species (D’Amen et al , 2015a; Araújo et al , 2019) but was considered appropriate for the study area as a whole because of its focus on precipitation‐related factors and seasonality, which usually prevail as drivers of plant diversity variation in the páramo (Peyre et al , 2019). To represent future scenarios and in order to encompass sufficient variance while reducing uncertainty in predictions (Thuiller et al , 2019), a total of eight climate change scenarios were selected, based on two representative concentration pathways (RCPs): CIMC5‐RCP45 and CIMC5‐RCP85, as well as four global circulation models (GCMs): bbc‐csm1‐1, CESM1‐BGC, HadGEM2‐AO and MRI‐CGCM3.…”

“…Third, current and future plant communities were assembled on the sky islands by stacking all previous probabilistic models and applying richness constraints and assembly rules. The vulnerability of the network of sky islands was assessed based on the magnitude of changes in species richness and species composition in terms of species numbers and ratio of mid‐páramo and super‐páramo species, expecting that locally diverse areas today (Peyre et al , 2019) would suffer faster and more drastic changes.…”

Impacts of Global Change on the Spatial Dynamics of Treeline in Venezuelan Andes

“…Second, to Include modern ecological modeling (Fulton et al, 2019), which is a crucial tool to understand vegetation and ecosystems' migration in climate change scenarios. Models of plant species distribution for the Páramo ecosystem have been made (Peyre et al, 2019(Peyre et al, , 2020, which need complete and adequate databases. Therefore, monitoring vegetation (Peyre et al, 2015;Cuesta et al, 2017) and landscape transformation studies are significant in implementing those models.…”

Review on the ecophysiology of important Andean fruits: Passiflora L.

“…Its width ranges from 250 to 750 km and occupies an area of about 2'870,000 km 2 (Orme, 2007). The tropical Andes represent 15% of total global plant richness, standing out as a region with very high biodiversity (Peyre et al, 2019;Campos et al, 2018), and many fruit species originate in these South American areas (Ligarreto, 2012). Izquierdo and Roca (1998) characterized this "ecoregion" as one of the most fragile and misunderstood, where more than 60 million people live, half of them working in fields and many of them have very low income.…”