Spatial patterns of tropical forest trees in Western Polynesia suggest recruitment limitations during secondary succession

2007 ◽  
Vol 23 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Janet Franklin ◽  
Sergio J. Rey

Spatial analysis can be used to relate the patterns of tree species to their regeneration syndromes – pioneer to late-successional – and is a first step in refining hypotheses about the species traits and biotic and abiotic factors that give rise to forest community dynamics. This study examines the spatial pattern of the most abundant trees in three 0.45-ha plots in species-poor lowland rain forests on oceanic islands in Tonga, Western Polynesia, that experience frequent natural disturbance and have a 3000-y history of shifting cultivation. We contrast secondary vs. remnant late-successional forest, with particular attention paid to the spatial dispersion and clustering of tree species, and the presence of spatial dependence in the density of seedlings and saplings. Shade-tolerant species were not strongly clustered at any scale. They did not appear to be dispersal limited, in late successional forest, and only some showed patterns consistent with density-dependent mortality (more clumped when small). Shade-tolerant species were more clumped in secondary forest, and may be dispersal-limited there because vertebrate dispersers prefer primary forest. Shade-intolerant species were clumped in gaps in late-successional forest, but some were also clumped in secondary forest, indicating that they too may be dispersal limited during secondary succession. We also compared the species composition of seedlings and saplings in the centre of plots with trees in the surrounding area and inferred that active dispersal (by vertebrate frugivores) contributed as much as 50% to site species richness.

2009 ◽  
Vol 39 (2) ◽  
pp. 430-440 ◽  
Author(s):  
Trevor A. Jones ◽  
Grant M. Domke ◽  
Sean C. Thomas

We used tree ring measurements to investigate the temporal response of basal area increment (BAI) of canopy trees following selection harvests by sampling across a chronosequence of stands with known harvest dates in tolerant hardwood (Great Lakes – St. Lawrence) stands in central Ontario. Seven tree species of various shade tolerances ranged widely in their responses to reduced competition. The more shade-tolerant species responded more positively: shade-tolerant species showed an average increase in BAI of 35% 4–15 years postharvest compared with 16% for mid-tolerant species and –7.5% for intolerant species. All species showed a time-lag in postharvest growth responses, with maximum growth responses occurring between 3 and 15 years postharvest. Tree size was the most important factor determining the magnitude of BAI response, with smaller trees consistently responding more than larger trees. We suggest that higher growth responses to selection harvests among shade-tolerant species may contribute to declines in mid-tolerant species abundance in selection-managed stands. More broadly, interspecific variability in canopy tree responses to forest disturbance appears to follow patterns distinct from seedling and sapling responses, with important implications to forest community dynamics in both managed and unmanaged forests.


1995 ◽  
Vol 73 (6) ◽  
pp. 817-826 ◽  
Author(s):  
D. J. Metcalfe ◽  
P. J. Grubb

Seed mass values are given for 140 species of primary lowland rain forest and associated secondary forests in Singapore. Among shade-tolerant species of primary forest there is a trend for a decrease in mean seed mass with tall trees > woody climbers > small trees > shrubs > herbs; the differences between tall trees and small trees or shrubs or herbs, and between herbs and small trees or woody climbers are significant. There are a few light-demanding herbs or shrubs in the primary forest; among small trees, light demanders have significantly lower seed mass values than shade tolerators. In 9 out of 13 comparisons within taxa including both shade tolerants and light demanders the former had appreciably larger seeds than the latter. Two out of 13 comparisons involved very small seeded shade tolerators, and one a notably large-seed light demander. Many shade-tolerant herbs, shrubs, and trees have seed mass values much smaller than those of trees of secondary forest conventionally regarded as small seeded, and exploit moist, litter-free sites, e.g., steep microslopes. The trees of secondary forests on degraded soils do not differ significantly in seed mass from those on nondegraded soils. Key words: seed mass, light requirement, regeneration, tropical rain forest, phylogenetic analysis.


2001 ◽  
Vol 17 (6) ◽  
pp. 859-869 ◽  
Author(s):  
DEBORAH LAWRENCE

Four common fallow tree species were tested for a response to nitrogen and phosphorus fertilization. Seedlings or cuttings of Melicope glabra (Rutaceae), Macaranga gigantea (Euphorbiaceae), Persea romosa (Laureaceae), Peronema canescens (Verbenaceae) were grown in pots of a 50:50 mix of native soil and sand under 18% full sun for 18 weeks. Every 2 weeks, plants received either added N, added P, added N+P, or no added nutrients (control). Persea, a shade-tolerant species, and Macaranga, a light-demanding pioneer, improved relative growth rate with the addition of both N and P. Neither responded to N or P alone. Peronema and Melicope demonstrated luxury consumption of both N and P but did not show enhanced growth. Two of the four species tested (Persea and Melicope) were more limited by P than N. Macaranga was equally limited by both and Peronema was more limited by N. Along with previous studies, evidence for positive growth response and luxury consumption among light-demanding species suggests that P, rather than N, should limit seedling performance and may ultimately influence tree diversity in young secondary tropical forests.


1993 ◽  
Vol 23 (7) ◽  
pp. 1347-1360 ◽  
Author(s):  
Jan W. McClure ◽  
Thomas D. Lee

Sampling of 24-, 34-, and 44-year-old patch cuts (324–2400 m2) in the Bartlett Experimental Forest, New Hampshire, was undertaken to assess the effect of gap size and location within a gap on tree species abundance (relative basal area and relative density). Shade-tolerant species, especially eastern hemlock (Tsugacanadensis (L.) Carr.) and American beech (Fagusgrandifolia Ehrh.), were relatively more abundant in small gaps and gap edges and generally decreased with increasing gap size. Shade-intolerant species, including paper birch (Betulapapyrifera Marsh.) and pin cherry (Prunuspensylvanica L.f.), were relatively more abundant in large gaps and gap centers and increased with increasing gap size. Intermediately shade-tolerant species, especially yellow birch (Betulaalleghaniensis Britt.) and red maple (Acerrubrum L.), were relatively more abundant in gap centers. Striped maple (Acerpensylvanicum L.) was relatively more abundant in gap edges. Many of these relationships were complex due to interactions with gap age and slope. Sugar maple (Acersaccharum Marsh.) relative abundance was not associated with gap size or location within a gap. Analyses isolating irradiance as a factor influencing species composition were inconclusive. Instead, other effects of gap disturbance and characteristics associated with different locations in the gap, such as soil conditions and root competition, may play an important role in the gap dynamics of this northern hardwoods forest. Gap age had a strong effect on species relative abundances and these patterns reflected typical successional sequences in northern hardwood forests. The gap disturbances increased species richness and diversity in this forest. Gaps contained species not present in the old-growth forest, and the species compositional variations among different gap sizes suggest that a forest with a range of gap sizes will have high diversity. Competitive exclusion appeared to be prevented by the gap disturbances, a likely consequence of the release of previously unavailable resources.


1998 ◽  
Vol 14 (3) ◽  
pp. 323-340 ◽  
Author(s):  
D. TORIOLA ◽  
P. CHAREYRE ◽  
A. BUTTLER

Secondary succession in a 19-y old tropical rainforest of French Guiana was investigated through the distribution pattern of primary forest species. The experimental plot of 25 ha was logged to simulate conditions of a paper pulp cut. Enumeration of all plants of height ≥ 50 cm in 52 subplots 10 m × 10 m indicated the number of species and individuals in five species categories; short-lived pioneer species, pioneer species that persist in mature forest, primary forest species capable of germinating in shade, primary forest species that indicate a preference for clearings (small gaps) in mature forest and understorey primary forest species. Change in proportion of the most abundant species (≥ 1 cm dbh) over the last 15 y indicated a decrease in short-lived pioneer species and an increase in pioneers that can persist in the mature forest. Proportion of species categories per height class indicated that primary forest species were mainly found in the lower height class in this forest which is largely dominated by secondary forest tree species forming a canopy that rarely exceeds 20 m. Individuals of primary forest species were encountered on ARBOCEL as sprouts from large stumps, sprouts from juveniles or as untraumatised saplings or juveniles. The distribution pattern in a 4-ha area of 11 selected primary forest canopy tree species revealed an overall trend in recolonisation of this species category in the secondary forest. Considered individually, the clustered distribution of stems of Eperua grandiflora showed the importance of regeneration through sprouting or remaining individuals. The gradient distribution, oriented from the edge to the centre of the studied plot, and displayed by the stem densities of Virola michelii, suggested a recent progressive dispersal of seeds. A more dynamic recolonisation front was observed for the primary forest understorey species Cassipourea guianensis and was probably linked to both the initial logging conditions and the fact that this species fruits when relatively young.


2000 ◽  
Vol 30 (10) ◽  
pp. 1571-1580 ◽  
Author(s):  
Elaine F Wright ◽  
Charles D Canham ◽  
K D Coates

Saplings of canopy tree species frequently undergo alternating periods of suppression and release before reaching canopy size. In this study, we document the effects of periods of suppression and release on current responses to variation in light by saplings of the 11 major tree species of northwestern, interior British Columbia. We were specifically interested in the degree to which increasing length of suppression had long-term effects on subsequent response to release in gaps or following partial cutting, and the degree to which the effects of suppression were ameliorated with time following release. At least some saplings of all 11 species had undergone alternating periods of suppression and release. The most shade-tolerant species generally did not show either a decline in growth over time during suppression or a gradual increase in growth at a given light level over time during release. The least shade-tolerant species exhibited significant declines in growth rate during suppression; however, in all of the species except trembling aspen (Populus tremuloides Michx.), the effects of suppression disappeared over time during release. Failure to account for the effects of past suppression and release leads to significant overestimates of the initial responses of shade-intolerant species to release. Our results suggest that competitive balances between species shift substantially over time as a result of growth history and that these shifts have significant effects on successional patterns.


2020 ◽  
Vol 21 (6) ◽  
Author(s):  
Mustaid Siregar ◽  
DANANG W. PURNOMO ◽  
HARTUTININGSIH M-SIREGAR ◽  
JOKO RIDHO WITONO

Abstract. Siregar M, Purnomo DW, Siregar HM, Witono JR. 2020. Vegetation and ecoregion analysis at Sipirok Botanic Gardens, South Tapanuli, North Sumatra, Indonesia. Biodiversitas 21: 2526-2535. Botanic Gardens is an ex-situ plant conservation area. Enrichment of plant collections of Botanic Gardens in Indonesia is based on ecoregion types. To find out the type of ecoregion, the existing vegetation, main native species should be known. The research aimed to analyze the existing vegetation and ecoregion type at Sipirok Botanic Gardens. Existing vegetation has been carried out using a separate plot method 20x20 m which is placed on purposively in nine locations considered to have different vegetation types, namely remnant forest, young secondary forests and shrubs, rubber plantation, and grasslands. Around 66 species belonged to 45 genera and 27 families were found in vascular plants (dbh ≥ 10 cm). There were 66 species of sapling belonged to 54 genera and 35 families, and 110 seedlings belonged to 87 genera and 50 families. The tree species that have the highest Importance Value Index are Ficus sumatrana (PU-1), Myristica fatua (PU-3), Hevea brasiliensis (PU-4 and PU-7), Artocarpus elasticus (PU-8), and Knema cinerea (PU-9). No trees were found in young secondary forest/shrub plots and grasslands. Unlike the species dominance index, the species diversity index and species equitability index are higher in natural forest plots. Beta diversity based on Jaccard similarity index and Whittaker's index shows a relatively different species composition among plots. Cluster analysis shows the tendency of grouping in 2 types of communities, namely: a) remnant forest communities, and b) secondary communities. The natural forest community is further divided into two communities consisting of remnant forest tree species and industrial/plantation plant species also secondary tree species. Secondary communities are also further divided into secondary forest communities and grasslands. Based on ecoregion analysis using previous publications, altitude, and diversity of plant species in the study site, Sipirok Botanic Gardens is a transitional zone of the Sumatran lowland rainforest and mountain rainforest.


2000 ◽  
Vol 16 (6) ◽  
pp. 865-882 ◽  
Author(s):  
DOUGLAS SHEIL ◽  
STEPHEN JENNINGS ◽  
PETER SAVILL

Species composition and turnover that have occurred in a series of permanent sample plots established during the 1930s and 1940s in Budongo, a semi-deciduous Ugandan forest, are reported. The plots were established as part of a sequence first used to describe forest succession, five of which have been maintained and which were last measured in 1992-1993. One plot (plot 7) provides 53 y of data from old-growth pristine forest. Plot 15 was established in wooded grassland at the forest edge and is now closed high forest. Evaluation of the remaining three plots is complicated by silvicultural interventions carried out in the 1950s. Forty species have been added since the first evaluations and a total of 188 tree species (over 80% of Budongo's forest tree flora, and including two exotics) has now been recorded from within the plots. The pattern of shade-tolerance in the original plot series conforms to patterns expected for succession with an increasing proportion of shade-tolerant species with development, and large stems appearing to ‘lag behind’ smaller stems in this respect. The time series data are less consistent, and while plot 7 increased in the proportion of shade-tolerant stems through time, the proportion of shade-tolerant species actually declines. Stem-turnover (the mean of mortality and recruitment) slowed with implied successional stage. Most species have a higher recruitment than mortality rate and stem numbers have thus increased in all plots. This is most pronounced in the putatively ‘early successional’ plot. Stem size structure has changed within the plots, with an increased proportion of smaller stems. Species show different rates of turnover and these vary from plot to plot and period to period. In plot 7, the overall mortality rate decreased with initial stem size. Estimates imply that some tree species may easily live longer than 500 y after reaching 10 cm DBH, and that 1000 y is possible. The importance of large trees in determining forest dynamics is illustrated by the finding that death of only seven stems in plot 7 contributed over 60% of net basal area losses recorded over the 53-y observation period. Many of the observed patterns were not predicted and could only have been found by long-term studies.


2019 ◽  
Vol 40 (2) ◽  
pp. 183-197 ◽  
Author(s):  
Elisée Bahati Ntawuhiganayo ◽  
Félicien K Uwizeye ◽  
Etienne Zibera ◽  
Mirindi E Dusenge ◽  
Camille Ziegler ◽  
...  

Abstract Tropical canopies are complex, with multiple canopy layers and pronounced gap dynamics contributing to their high species diversity and productivity. An important reason for this complexity is the large variation in shade tolerance among different tree species. At present, we lack a clear understanding of which plant traits control this variation, e.g., regarding the relative contributions of whole-plant versus leaf traits or structural versus physiological traits. We investigated a broad range of traits in six tropical montane rainforest tree species with different degrees of shade tolerance, grown under three different radiation regimes (under the open sky or beneath sparse or dense canopies). The two distinct shade-tolerant species had higher fractional biomass in leaves and branches while shade-intolerant species invested more into stems, and these differences were greater under low radiation. Leaf respiration and photosynthetic light compensation point did not vary with species shade tolerance, regardless of radiation regime. Leaf temperatures in open plots were markedly higher in shade-tolerant species due to their low transpiration rates and large leaf sizes. Our results suggest that interspecific variation in shade tolerance of tropical montane trees is controlled by species differences in whole-plant biomass allocation strategy rather than by difference in physiological leaf traits determining leaf carbon balance at low radiation.


2008 ◽  
Vol 22 (2) ◽  
pp. 589-598 ◽  
Author(s):  
William Goulart da Silva ◽  
Jean Paul Metzger ◽  
Luis Carlos Bernacci ◽  
Eduardo Luís Martins Catharino ◽  
Giselda Durigan ◽  
...  

The aim of this work was to explore the relationship between tree species richness and morphological characteristics of relief at the Ibiúna Plateau (SE Brazil). We sampled 61 plots of 0.30 ha, systematically established in 20 fragments of secondary forest (2-274 ha) and in three areas within a continuous secondary forest site, Morro Grande Reserve (9,400 ha). At each plot, 100 trees with diameter at breast height > 5 cm were sampled by the point centered quarter method, and total richness and richness per dispersal and succession class were obtained. The relief was characterized by the mean and variance of slope, elevation, aspect and slope location. There was no significant relationship between relief heterogeneity and tree species richness. Relief parameters generally did not affect tree richness, but elevation was particularly important especially in the continuous forest. Despite the limited range of altitudinal variation (150 m), species richness increases with elevation. The highest areas were also those with the largest forest cover and the lowest disturbance degree, which should contribute to the greater richness of those sites. Our results suggest an indirect influence of relief, due to the fact that deforestation is less intense in higher regions, rather than a direct influence of abiotic factors related to the altitudinal gradient.


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