Questions: To gain insights into the role of species-by-species replacements in cloud forest community structuring, we asked: (1) What are the effects of the spatial distribution of standing individuals on the seed rain, soil seed bank, and sapling density and survival in this cloud forest? and (2) What is the prevalence of conspecific vs. heterospecific replacements in the regeneration of this forest?

Location: Santo Tomás Teipan, Oaxaca State, southern Mexico.

Methods: In a 1-ha cloud forest plot we assessed seed rain, seed bank, and sapling density and survival of four canopy tree species (Chiranthodendron pentadactylon, Cornus disciflora, Quercus laurina, Oreopanax xalapensis). All standing individuals of these and other tree species (dbh ≥ 2.5 cm) were mapped. We used neighbourhood models to examine the spatial patterns of the three life cycle stages relative to the spatial distribution of adults. The neighbourhood effect was assessed through the Neighbourhood Index, which integrates information on size (dbh) and distance to adults. Data analysis was based on maximum likelihood and model selection procedures.

Results: We found large between-species differences regarding the spatial patterns of seeds and saplings. Three species showed evidence for the Janzen-Connell effect operating at the seed (C. pentadactylon and Q. laurina) or sapling (O. xalapensis) stage. We also found support for a critical role of specific microsite factors (i.e., niche differentiation) in the regeneration of two species (C. pentadactylon and C. disciflora).

Conclusions:  Seed and sapling distribution patterns suggest the prevalence of heterospecific replacements, and that both Janzen-Connell and niche differentiation effects contribute to this pattern. Our results largely support the notion that the prevalence of heterospecific replacements among canopy species promotes species coexistence in cloud forest.

Please see article in the Journal of Vegetation Science for a detailed description of field and analytical methods.

Mejía-Domínguez et al., 2021 Data.

The data come from the 2007 census of 1-ha cloud forest plot in Teipan, Oaxaca, southern Mexico (16°15’ N; 95°58’ W; 2200-2500 m asl). The format is an Excel Book.

Page 'data_dbh>2.5' contains coordinates in the 1-ha (100 m × 100 m) plot, diameter at breast height (dbh, cm) and species identity (see species codes below).

Page 'Seed_rain' contains coordinates of subplot in the 1-ha plot and density for four species, for the seed rain stage.

Page 'Seed_bank' contains coordinates of subplot in the 1-ha plot and density for four species, for the seed bank stage.

Page 'Saplings_2007_2008' contains coordinates of subplot in the 1-ha plot and density for two species at the seedling stage.

Species codes in all pages of the Excel Book: CHPE, Chiranthodendron pentadactylon; CODI, Cornus disciflora; ORXA, Orepanax xalapensis; QULA, Quercus laurina; SRS set of remaining tree species.

Mejía-Domínguez _et _al_2021_DataBase.xlsx

Mejía-Domínguez et al., 2021 Script.

R script for calculating neighbourhood index (NI) and estimating neighbourhood models (see Data analysis in article for details).

Mejía-Domínguez_et_al_2021_code.R