DOI: 10.5061/dryad.902k846
title: Data from: The influence of topography and soil phosphorus on the vegetation of Korup Forest Reserve, Cameroun

description: All living trees (≥ 30 cm gbh) were enumerated in 135 80×80 m plots, each
 subdivided into four 40×40 m subplots, and arranged along four 5 km
 transect lines in the Korup Forest Reserve, Cameroun. For each plot
 altitude, slope and the extent of permanent and seasonal swamps were
 recorded. Four hundred and eleven taxa were recognized of which 66% were
 identified to species. Mean tree density was 471 ha−1, basal area 27.6 m2
 ha−1 and number of species per plot 75. The subfamily Caesalpinioideae
 (Leguminosae) was the most abundant family/subfamily in terms of basal
 area, but the Scytopetalaceae the most frequently represented, mainly on
 account ofOubanguia alata. Ten plots had at least three quarters of their
 area permanently swamped, and three, to a similar extent, were seasonally
 swamped. The ranges in sand, silt and clay content were 60–91, 0–24 and
 4–20% respectively. The pH value, organic carbon content and
 nitrate-nitrogen concentration ranged between 4.0–5.8, 1.3–5.7% and 0–35
 ppm respectively. The largest soil variations were in available
 phosphorus, range 2–29 ppm, and potassium, 38–375 ppm. Correspondence
 analysis ordination of all plots showed a major indirect floristic
 gradient correlated with increasing altitude, slope and soil phosphorus
 and potassium. Removal of the topographic effect by separate
 re-ordinations of four groups of plots at low, middle (2) and high
 altitude/slopes highlighted a strong correlation of the main floristic
 gradients of the middle altitude/slope groups with the concentration of
 available soil phosphorus. Direct gradient analysis using all plots with
 respect to available soil phosphorus concentration confirmed the indirect
 analyses. Individual species response to phosphorus were also shown by
 direct comparisons in the vegetation on plots of high and low available
 soil phosphorus concentration. Low available phosphorus soils (≤ 5 ppm)
 are strongly associated with species of the subfamily Caesalpinioideae,
 especially of the tribes Amherstieae and Detarieae. It is suggested that
 this result is probably due to the ability of these particular legume
 tribes to form associations with ectotrophic mycorrhizae.
description: Southern Korup Transect
 Plots DataText to files on Korup
 plot data of Gartlan and Thomas In the southern part of Korup National
 Park (58o10 N, 8o70 E), 135 plots, each of 80 m x 80m in area, were laid
 out at 150-m intervals along four E-to-W transect lines (P, Q, R and S;
 each of 34 plots, excepting Q with 33). Lines were ~5 km in length, and
 separated S-to-N at ~4 km distance. Shrubs and small trees were very
 lightly cut to show a way between plots. Each plot was divided into four
 40-m x 40-m subplots, although only data at the whole plot level are
 archived here. Details of the layout and environmental information are
 found in Gartlan et al. (1986). All trees of ≥ 30 cm gbh (girth at breast
 height, 1.3 m) were measured and identified. Coordinate locations of trees
 within subplots were not taken: trees were not tagged. Lianas were also
 recorded but are not included here. The plots were not marked at their
 corners in any permanent manner apart from an indication of their location
 by single tags on trees at the start of each plot on the line. The field
 work was undertaken in 1975-1977, principally by J. S. Gartlan, D. W.
 Thomas and F. Namata. Plots were relocatable up to about 1998, after which
 time many tags had become very difficult to find. Except for transect P,
 the southernmost line, and which has continued in use for further research
 up until the present, the other lines have faded. There are four
 ASCII-text files. These were the inputs for the abundance tables,
 classifications and ordinations in Gartlan et al. (1986). (1) ‘korbar.txt’
 has the basal areas (ba) per plot (units: m2/0.1-ha) of each tree species,
 written in the Cornell Condensed Format (CCF) of the programs DECORANA and
 CANOCO. Each line of the data has a plot number followed by four couplets
 of ‘species number and ba-value’. (Some lines have trailing zero entries.)
 Plots numbers are: 1-34, transect P; 35-67, Q; 68-101, R; and 102-135, S.
 (2) ‘korfre.txt’ has the numbers of trees of each tree species per plot,
 corresponding to ‘korbar.txt’ and also in the CCF. (3) ‘korlsp.txt’
 contains a list of the 444 species’ identifier codes (all transects); and
 (4) ‘kortax.txt’ is a dictionary of these species’ codes giving their full
 Latin names and authorities as of 1986, arranged under family names. The
 taxonomy has not been updated, and the modern user may want to revise it
 using an international plant names’ index. These data were also the basis
 to Newbery & Gartlan (1996) and Newbery et al. (1988, 1997, 1998).
 _References Gartlan, J. S., D. M. Newbery, D. W. Thomas, and P. G.
 Waterman. 1986. The influence of topography and soil phosphorus on the
 vegetation of Korup Forest Reserve, Cameroun. Vegetatio 65:131-148.
 Newbery, D. M., I. J. Alexander, and J. A. Rother. 1997. Phosphorus
 dynamics in a lowland African rain forest: The influence of
 ectomycorrhizal trees. Ecological Monographs 67:367-409. Newbery, D. M.,
 I. J. Alexander, D. W. Thomas, and J. S. Gartlan. 1988. Ectomycorrhizal
 Rain-Forest Legumes and Soil-Phosphorus in Korup-National-Park, Cameroon.
 New Phytologist 109:433-450. Newbery, D. M. and J. S. Gartlan. 1996.
 Structural analysis of the rain forest at Korup and Douala Edea, Cameroon.
 Proceedings of the Royal Society of Edinburgh B 104:177-224. Newbery, D.
 M., N. C. Songwe, and G. B. Chuyong. 1998. Phenology and dynamics of an
 African rain forest at Korup, Cameroon. Pages 267-308 in D. M. Newbery, H.
 H. T. Prins, and N. D. Brown, editors. Dynamics of tropical communities.
 Blackwell Science, Oxford.