FRUTING PHENOLOGY OF EIGHT Shorea SPECIES IN SINHARAJA MAN AND BIOSPHERE RESERVE

The canopy of Sinharaja rain forest is dominated by Mesua and Shorea spp., which areendemic to Sri Lanka. Information on the fruiting phenology of Shorea is vital, in termsof identifying trees as mother trees and collecting seeds for restoration and reforestationof degraded forest areas in the south-western part of Sri LankaThe phenology of eight Shorea species, [SO affinis, S. congestiflora, S. trapezifolia and S.zeyJanica belonging to the Thiniya group and S. cordifolia, S. megistophyJ/a, S.worthingtonii and S. disticha belonging to the Beraliya group] were examined foreighteen years. Fruiting of selected individuals was recorded fort-nightly as a percentageof the observable part of the crown in flower. The effect of environmental parameters onfruiting was assessed using Spearman rank correlation coefficient.In all species, the number of trees participating in a given fruiting event differed greatlybetween years. Individuals of S. trapezifolia and S. zeyJanica had more intense fruitingactivity (>50%) in most years while, it was only 1-50% in S. congestiflora. Fruitingintensities of individuals of the Beraliya group varied relatively little among differentfruiting episodes. An annual fruiting pattern among the Thiniyas and a supra-annualpattern in the Beraliyas were observed. The number of flowering episodes per tree washigh in members of the Thiniya group. Fruit fall was tightly synchronized among theBeraliyas, but sequential among the Thiniyas.The monthly rainfall and the fruiting intensities of all Shorea species, except in S.cordifolia and S. zeyJanica, were significant. The seasonal rainfall and fruitingintensities of four Shorea species were significantly correlated. The timing and intensityof fruitingwas observed to coincide with favorable environmental conditions.This project was funded by grants from by the USAID (Grant No: DPE-5542-G-55-4073-00) through Harvard University, U. S. A. and the John D. and Catherine T.MacArthur Foundation and the Britin Scholarship Fund

COMPARISON OF FLORISTIC DIVERSITY OF FOUR WOODLAND TYPES IN THE UPPER HANTANA CAMPUS LAND

In the Upper Hantana campus land, three broad-leaf woodlands Peresereanthes fa/cataria.A /stonia macrophylla, or mixed species woodland and Pinus caribaea woodland grow inproximity to one another. The wide range of floristic diversity exhibited by these differentwoodlands was compared using plot sampling.The overstorey vegetation of the Alstonia woodland showed the highest, i) density, ii)floristic richness, iii) proportion of endemics and iv) plant diversity, foIlowed in decreasingorder by that in the Peresereanthes-, mixed-, and Pinus woodland. In the understoreyvegetation, floristic diversity «10 ern) was highest in Peresereanthes woodland, foIlowedin decreasing order by that in Alstonia-, mixed species-, and Pinus woodlands. Speciesrank abundance plots of overstorey and understorey species show that over storeyvegetation in Pinus woodland, fits the geometric series, whereas the others fit the logseries or log normal model.The broad-leaf species woodlands in Upper Hantana also showed better naturalregeneration of an array of species. AIl woodlands showed differences in micro-siteconditions. Levels of human disturbance and burning may contribute to differencesamongst them. These results provide baseline ecological information on naturalregeneration in different woodland types and indicate their relative potential forconservation of biodiversity and water resources.

Kandyan home gardens: Faunal repositories in Sri Lanka.

Kandyan home gardens are one of the major designs of sustainable land use systems that have evolved over hundreds of years incorporating high biodiversity and providing a diverse and stable supply of socio-economic products and service benefits to householders in Sri Lanka. A study was carried out in three home gardens in the Kandy district from May to December 2009 with the objectives of (a) identifying spatial distribution of terrestrial vertebrates in different vegetation strata, (b) their diurnal and seasonal variations, (c) plant-animal interactions, (d) nesting habits and (e) diet composition. A total of 93 terrestrial vertebrate species including seven amphibians, 23 mammals, 43 birds, and 20 reptiles were recorded. These comprised 14 endemic species, 71 native, four introduced mammals and two migrant birds. Terrestrial vertebrate assemblages were similar in Home garden 1 and 3. According to the fully-nested ANOVA, statistically significant differences were found in the composition of terrestrial vertebrates and the home gardens (P=0.005<0.05), and their vegetation strata (P=0.005<0.05). However, no statistically significant differences were observed between richness of terrestrial vertebrates and the monsoonal periods (P=0.966>0.05), as well as the time of the day (P=0.775>0.05). A positive relationship was obtained between canopy cover and number of bird nests in all home gardens (rs = +1, α = 0.05).Commensalism was the most frequently recorded relationship in all three home gardens. Overall, the diversity of animals and their interactions were different in the three Kandyan Home Gardens studied. Preventing the degradation of home gardens can be considered as a means of conserving biodiversity. There is scope to develop the Kandyan Home Garden system as an important strategy to conserve biodiversity outside the natural and protected area systems

LEAF ADAPTABILITY OF lWO NON·TIMBER FOREST SPECIES Caryota urens L. AND Elettaria carrlamomum VAR. MAJOR PLANTED IN THE Pinus caribaea ENRICHMENT BUFFER ZONE IN SINHARAJA MAB RESERVE, SRI LANKA

Caryota urens L. and Elettaria cardamomum var. major are indigenous non-timberspecies which are used as market or sustainable goods and services for human orindustrial consumption. Both species thrive well in disturbed forest areas in the southwesternpart of Sri Lanka. Being understorey species, the growth of these species areaffected by sun light which is highly variable and often limiting resource in the forest.In a Pinus enrichment study established in 1991, leaf anatomical adaptability of these twospecies after 12 years of initial establishment under the Pinus buffer zone of the SinharajaMAB .reserve was investigated. Different light levels in the study area were created bythinning Pinus trees at different densities.Lower epidermis of C. urens showed highest (7.75 %) and lowest (6.35 %) stomatalindices in 2 pine rows removed treatment (2R) and 5 pine rows removed treatment (5R)respectively. Corresponding values for E. cardamomum were 6.00 % (highest) in theclosed canopy control (CU) and 5.22 % (lowest) in 1 pine row removed treatment (lR).The highest thickness of C. urens leaf cuticle (0.2611 ±0.02), leaf blade (22.2711 ±2.l4),upper epidermis (1.7511 ±0.10), lower epidermis (1.8311 ±0.06), palisade layer (6.2511±0.87) and spongy mesophylliayer (11.7411 ±1.30) were observed in 5R treatment thatreceived relatively high light levels than other treatments.E. cardamomum leaves showed highest thickness of leaf blade (22.4311 ±O.88), lowerepidermal layer (2.1211 ±O.ll), spongy mesophyll layer (10.3211 ±O.57) in 3 pine rowsremoved treatment (3R). The highest cuticle thickness (0.2311 ±O.OI) was recordered in 3pine rows under planting treatment (3U) while lR treatment showed highest upperepidermal layer thickness of 2.2111 ±0.15. Palisade layer was highest (4.74J! ±0.55) inCU.Results revealed that C. urens shows leaf adaptability to grow under relatively high sunlight levels (5R treatment) while E. cardamomum shows most of the leaf adaptabilitycharacters to grow under moderate light levels (3R treatment).The knowledge gained by this study is useful to recommend the optimum lightrequirements in terms of leaf anatomical traits of the study species.

Use of Gliricidia sepium as a Nurse Plant to Reforest Man-made Grasslands in the Knuckles Forest Reserve, Sri Lanka

Biodiversity richness and socially beneficial watershed services are high in the KnucklesForest Reserve. However, the lower montane forest patches on the eastern slopes of the KFRare highly fragmented mainly due to anthropogenic disturbances. If these forest fragments arenot connected in the near future, they will disappear from the landscape due to their lowregeneration rates. Native tree species when used for restoration of these lands faces manydifficulties due to various biotic and abiotic stresses including harsh microclimatic conditionsand infertile soils. Therefore, usage of a nurse plant will facilitate the growth of target speciesdue to creation of favourable microclimatic conditions. Gliricidia sepium has been used as ashade plant in Sri Lanka, since colonial times. More recently it has been used for indigenousfarming practices, soil stabilization, living fences and as fuel wood, animal forage, greenmanure. In our research we investigate the potential of G. sepium as a nurse plant to establishfour native tree species on man-made grasslands in central Sri Lanka. The study wasconducted on four blocks of grasslands. Four replicates of each of the three island sizes(small 4 m2, medium 16 m2, and large 64 m2) were created inside each block. One set ofislands in each block were planted with G. sepium stakes at 2 m intervals in a grid format.The other set of islands in each block was kept as a control without planting G. sepiumstakes. Seedlings of Macaranga indica, Bhesa ceylanica, Symplocos cochinchinensis andEugenia bracteata were planted randomly in islands with and without G. sepium stakes.After three months of establishment, the survival rate of G. sepium in the four blocks wasmore than 80% and the survival rate of the G. sepium was 20% higher in the small andmedium islands than the large islands. The mean number of sprouts per stake was more thaneight in medium and large islands and less than six in small islands. The mean survival ratewas higher (5.8%) and the mean growth rates was lower (0.006%) for all the four nativespecies with G. sepium than without G. sepium after three months of planting. G. sepiumincreased the survival rates of native species after three months of establishment due tofavourable microclimatic conditions created by them. However, growth rate of the nativespecies which were planted with G. sepium was lower probably due to interspecificcompetition. Therefore, G. sepium can be used as an effective nurse plant in initial phases ofreforestation programmes to increase the survival rates of native tree species on degradedsubmontane sites in Sri Lanka.

Comparing tropical forest tree size distributions with the predictions of metabolic ecology and equilibrium models

Tropical forests vary substantially in the densities of trees of different sizes and thus in above-ground biomass and carbon stores. However, these tree size distributions show fundamental similarities suggestive of underlying general principles. The theory of metabolic ecology predicts that tree abundances will scale as the -2 power of diameter. Demographic equilibrium theory explains tree abundances in terms of the scaling of growth and mortality. We use demographic equilibrium theory to derive analytic predictions for tree size distributions corresponding to different growth and mortality functions. We test both sets of predictions using data from 14 large-scale tropical forest plots encompassing censuses of 473 ha and \u3e 2 million trees. The data are uniformly inconsistent with the predictions of metabolic ecology. In most forests, size distributions are much closer to the predictions of demographic equilibrium, and thus, intersite variation in size distributions is explained partly by intersite variation in growth and mortality. © 2006 Blackwell Publishing Ltd/CNRS

Assessing Evidence for a Pervasive Alteration in Tropical Tree Communities

In Amazonian tropical forests, recent studies have reported increases in aboveground biomass and in primary productivity, as well as shifts in plant species composition favouring fast-growing species over slow-growing ones. This pervasive alteration of mature tropical forests was attributed to global environmental change, such as an increase in atmospheric CO2 concentration, nutrient deposition, temperature, drought frequency, and/or irradiance. We used standardized, repeated measurements of over 2 million trees in ten large (16–52 ha each) forest plots on three continents to evaluate the generality of these findings across tropical forests. Aboveground biomass increased at seven of our ten plots, significantly so at four plots, and showed a large decrease at a single plot. Carbon accumulation pooled across sites was significant (+0.24 MgC ha−1 y−1, 95% confidence intervals [0.07, 0.39] MgC ha−1 y−1), but lower than reported previously for Amazonia. At three sites for which we had data for multiple census intervals, we found no concerted increase in biomass gain, in conflict with the increased productivity hypothesis. Over all ten plots, the fastest-growing quartile of species gained biomass (+0.33 [0.09, 0.55] % y−1) compared with the tree community as a whole (+0.15 % y−1); however, this significant trend was due to a single plot. Biomass of slow-growing species increased significantly when calculated over all plots (+0.21 [0.02, 0.37] % y−1), and in half of our plots when calculated individually. Our results do not support the hypothesis that fast-growing species are consistently increasing in dominance in tropical tree communities. Instead, they suggest that our plots may be simultaneously recovering from past disturbances and affected by changes in resource availability. More long-term studies are necessary to clarify the contribution of global change to the functioning of tropical forests

Testing metabolic ecology theory for allometric scaling of tree size, growth and mortality in tropical forests

The theory of metabolic ecology predicts specific relationships among tree stem diameter, biomass, height, growth and mortality. As demographic rates are important to estimates of carbon fluxes in forests, this theory might offer important insights into the global carbon budget, and deserves careful assessment. We assembled data from 10 old-growth tropical forests encompassing censuses of 367 ha and > 1.7 million trees to test the theory's predictions. We also developed a set of alternative predictions that retained some assumptions of metabolic ecology while also considering how availability of a key limiting resource, light, changes with tree size. Our results show that there are no universal scaling relationships of growth or mortality with size among trees in tropical forests. Observed patterns were consistent with our alternative model in the one site where we had the data necessary to evaluate it, and were inconsistent with the predictions of metabolic ecology in all forests

Response to Comment on “Plant diversity increases with the strength of negative density dependence at the global scale”

Hülsmann and Hartig suggest that ecological mechanisms other than specialized natural enemies or intraspecific competition contribute to our estimates of conspecific negative density dependence (CNDD). To address their concern, we show that our results are not the result of a methodological artifact and present a null-model analysis that demonstrates that our original findings—(i) stronger CNDD at tropical relative to temperate latitudes and (ii) a latitudinal shift in the relationship between CNDD and species abundance—persist even after controlling for other processes that might influence spatial relationships between adults and recruits