Tree Saplings Research Articles

Damage and management of cyclone Sidr-affected homestead tree plantations: a case study from Patuakhali, Bangladesh

Geographically, Bangladesh is considered to be one of the most cyclone-prone areas in the world. The super cyclone Sidr in 2007 was one of the most devastating disasters to have ever occurred in Bangladesh, having wind speeds of 223 km/h with a tidal surge of 6.1–7.6 m high. In order to draw a pre- and post-Sidr damage and management scenario, a survey was conducted at Dumki upazila, Patuakhali district in Bangladesh with a pretested questionnaire. Primary data were collected through a questionnaire, while secondary data were collected from pertinent offices as well as academic journals. The major focus of this study was to assess the state of pre-Sidr tree plantations (woody and fruit trees), the devastation caused by Sidr on these tree plantations, and post-Sidr recovery and further sustainable management initiatives to counteract a possible future neo-Sidr. The post-Sidr study showed that about 16.84 million woody and fruit trees were uprooted by Sidr. A total of 3,120 rain tree (Samanea saman L.), 7,548 mahogany (Swietenia mahagoni L.), 1,444 royal siris (Albizzia richardiana L.), 702 white siris (Albizzia procera L.), 1,214 mango (Mangifera indica L.), 1,092 coconut (Cocos nucifera L.), 1,380 jackfruit (Artocarpus heterophyllus L.), and 7,640 betel nut (Areca catechu L.) trees were sampled among which 922, 1,662, 382, 210, 106, 38, 362, and 1,652 trees, respectively, were markedly damaged by Sidr. Sexually propagated woody trees with a damaged taproot were vulnerable to heavy wind during the cyclone. Fruit trees were more resistant to the cyclone than other types of trees, and the lack of proper tree training and pruning was one of the principal causes of the severe damage to woody trees. Hence, plantations of woody tree saplings with damaged taproots are strongly discouraged. However, proper training and pruning of homestead trees together with plantation of fruit trees rather than woody trees is suggested as a possible effective management strategy to protect the homestead ecosystem from devastation by future cyclones in Bangladesh.

Effects of grasses on sapling establishment and the role of transplanted saplings on the light environment of pastures: implications for tropical forest restoration

AbstractQuestionDoes the presence of grasses affect the establishment (survival and growth) of tree saplings in an abandoned tropical pasture, and what is the potential of established saplings to modify pasture microenvironmental conditions, particularly light incidence?LocationAbandoned cattle pasture, in the humid tropics of SE Mexico (18°25′–18°45′ N, 95°00′–95°18′ W).MethodsThe establishment of four native fast‐growing tree species in a tropical abandoned pasture was evaluated. Saplings of Cecropia obtusifolia, Hampea nutricia, Omphalea oleifera and Erythrina folkersii were transplanted using a split‐plot design. Plant survival and growth were evaluated over 12 mo under two experimental treatments: presence and absence of grasses. Light incidence at ground level was used to evaluate microclimate conditions under the grass matrix, compared to light incidence under saplings established in the pasture.ResultsSaplings had high survival (49–88%) regardless of the presence of grasses. In the presence of grasses, growth of surviving saplings either increased or was not impacted, and in only one out of eight comparisons did grasses negatively affect growth. The impact of saplings on light incidence in abandoned pastures depended on sapling species architecture: species with large total leaf area and canopy area ( H. nutricia and E. folkersii) significantly reduced light incidence (12–29% of total incidence), while narrow‐canopy species ( C. obtusifolia and O. oleifera) generated less intense shade (37–89% of total incidence).ConclusionsGrasses did not seem to represent a crucial limiting factor in sapling establishment of fast‐growing native species in the short term. In addition, shading by recruited saplings of some native species could be important to out‐compete grasses in the future, as well as for ‘facilitating’ regeneration of more shade‐tolerant species. Transplantation of fast‐growing native saplings into abandoned pastures, even without manipulation of the grasses, could be a useful practice for landscape‐scale restoration programmes in tropical areas. Evaluation of the longer‐term consequences (beyond the 1‐yr span of this study) warrants further research.

Ecological thresholds at the savanna‐forest boundary: how plant traits, resources and fire govern the distribution of tropical biomes

Fire shapes the distribution of savanna and forest through complex interactions involving climate, resources and species traits. Based on data from central Brazil, we propose that these interactions are governed by two critical thresholds. The fire-resistance threshold is reached when individual trees have accumulated sufficient bark to avoid stem death, whereas the fire-suppression threshold is reached when an ecosystem has sufficient canopy cover to suppress fire by excluding grasses. Surpassing either threshold is dependent upon long fire-free intervals, which are rare in mesic savanna. On high-resource sites, the thresholds are reached quickly, increasing the probability that savanna switches to forest, whereas low-resource sites are likely to remain as savanna even if fire is infrequent. Species traits influence both thresholds; saplings of savanna trees accumulate bark thickness more quickly than forest trees, and are more likely to become fire resistant during fire-free intervals. Forest trees accumulate leaf area more rapidly than savanna trees, thereby accelerating the transition to forest. Thus, multiple factors interact with fire to determine the distribution of savanna and forest by influencing the time needed to reach these thresholds. Future work should decipher multiple environmental controls over the rates of tree growth and canopy closure in savanna.

Plant traits affecting herbivory on tree recruits in highly diverse subtropical forests

Differences in herbivory among woody species can greatly affect the functioning of forest ecosystems, particularly in species-rich (sub)tropical regions. However, the relative importance of the different plant traits which determine herbivore damage remains unclear. Defence traits can have strong effects on herbivory, but rarely studied geographical range characteristics could complement these effects through evolutionary associations with herbivores. Herein, we use a large number of morphological, chemical, phylogenetic and biogeographical characteristics to analyse interspecific differences in herbivory on tree saplings in subtropical China. Unexpectedly, we found no significant effects of chemical defence traits. Rather, herbivory was related to the plants' leaf morphology, local abundance and climatic niche characteristics, which together explained 70% of the interspecific variation in herbivory in phylogenetic regression. Our study indicates that besides defence traits and apparency to herbivores, previously neglected measures of large-scale geographical host distribution are important factors influencing local herbivory patterns among plant species.

Drought‐induced mortality affects understory vegetation: release after death

AbstractIn recent decades, severe droughts have become an important cause of canopy disturbance in forests, and have shown potential to cause rapid and pronounced vegetation shifts. Under dead canopy, undamaged understory could influence the nature of resource limitation for seedling growth and survival, limiting forest regeneration. We assessed the release response of understory vegetation after a severe drought event in temperate forests of northern Patagonia. Growth trends of dominant tree saplings, and changes in vegetation biodiversity and cover were compared between drought‐dead and unaffected canopy. Nothofagus dombeyi undergo growth release after the climatic event in affected forests, and the response was evidenced immediately after the disturbance. For Austrocedrus chilensis, the growth release response was less evident, due mainly to a difference in age structure. In the understory the release response was barely discernable for some components. There was a tendency towards higher cover of the shrub layer in the understory of drought‐affected forests, and an important presence of the exotic shrub Rosa rubiginosa. However, the clearest biotic response following drought mortality was the release in growth of understory dominant tree component. Those results strongly suggest that the environment under drought‐dead canopy, and the die‐off in woody sapling cohorts in a self‐thinning process, could favor crown expansion and growth release of understory species that could help predict future forest trajectories in the context of the influence of climatic extreme events.

Age and distribution of an evergreen clonal shrub in the Coweeta Basin: Rhododendron maximum L.1

Rhododendron maximum L. is an evergreen, clonal shrub that forms a dominant sub-canopy layer and is a key species in southern Appalachian forests. We investigated the age and distribution of R. maximum across the Coweeta Basin, a 1626 ha watershed in western North Carolina. We selected 16 perennial, second-order streams and used a Global Positioning System to establish site boundaries and map the coverage of R. maximum across the hillslopes from stream to ridge. In each site, three transects from stream edge to the ridge were used to measure diameters of overstory trees (≥ 2.5 cm dbh), tree saplings (< 2.5 cm dbh) and shrubs including R. maximum stems. Along each transect, we cut cross-sections of R. maximum ramets and extracted increment cores from nearest neighbor trees to determine ages. The 16 sites ranged in size from 0.3 to 1.9 ha depending on the distance from stream to ridge. Rhododendron maximum cover ranged from 25 to 100% and ages ranged from 6 to 120 years. Rhododendron maximum establishment year showed a skewed unimodal distribution with the peak establishment occurring between 1928 and 1940. Although the R. maximum age and distance-from-stream relationship was statistically significant, the relationship was not meaningful as distance-from-stream only explained 2.6% of the variation in R. maximum age (r2 = 0.026, P = 0.0003, n = 487). Distance from stream only explained 4.2% of the variation in overstory tree age (r2 = 0.042, P = 0.0015, n = 237). It appears that R. maximum has not expanded upslope over the last 100 years; rather the ranges in sizes and ages suggest that ramets are recruiting under established R. maximum canopies particularly in the wetter, near stream locations.

Mechanisms promoting tree species co‐existence: Experimental evidence with saplings of subtropical forest ecosystems of China

AbstractQuestionsThe maintenance of a diverse sapling pool is of particular importance for the regeneration and persistance of species‐rich forest ecosystems. However, the mechanisms of co‐existence of saplings have rarely been studied experimentally. Do species richness, species composition, species identity and stand density affect the co‐existence, growth patterns and crown architecture of tree saplings?LocationJiangxi Province, southeast China.MethodsIn a field experiment, we manipulated the local neighbourhood of saplings of four early‐successional subtropical species (Schima superba,Elaeocarpus decipiens,Quercus serrataandCastanea henryi) with regard to species richness (one, two and four species), species composition (monocultures, six‐two‐species combinations and one‐four‐species combination) and stand density (low, intermediate and high). We tested for treatment effects and impact of species identity on growth variables, biomass allocation, crown architectural traits and branch demography.ResultsSpecies richness was a poor predictor of all response variables, but enhanced pruning and branch turnover. In contrast, species composition proved to be of great importance for growth, biomass allocation, crown architecture and branch demography. Local neighbourhood interactions of saplings were characterized by complementary or facilitative, as well as by competitive mechanisms. Intra‐specific competition was higher than inter‐specific competition for two species (C. henryi,Q. serrata) depending on the respective species combination. To a high degree, the competitive ability of species can be explained by species identity. Competition for light likely played a major role in our experiment, as evidenced by the strong response of crown architecture and branch demography to the manipulated predictor variables.ConclusionsEffects of species composition and species identity on growth rates and crown architecture variables of tree saplings point to niche separation as a mechanism of species co‐existence, while effects of species richness were not yet prominent at the sapling life stage.

Regeneração de espécies arbóreas sob a influência de Merostachys multiramea Hack. (Poaceae) em uma floresta subtropical

A ocorrência de bambúseas é comum em muitas fisionomias florestais, sendo que a elevada abundância destas espécies pode interagir com a regeneração de espécies arbóreas. Foi avaliada a regeneração de espécies arbóreas e de Merostachys multiramea Hack. em uma área de transição entre Floresta Ombrófila Mista e Floresta Estacional no Sul do Brasil e comparada a estrutura de regeneração da área entre dois e quatro anos após floração, frutificação e morte de M. multiramea. Foram alocadas 25 unidades amostrais de 100 m² dispostas de forma aleatória, onde foram amostrados todos os colmos vivos de M. multiramea e indivíduos regenerantes de espécies arbóreas &gt; 30 cm de altura e com perímetro à altura do peito &lt; 15 cm. Foram amostrados 4.372 indivíduos vivos de bambu e 2.918 indivíduos regenerantes, pertencentes a 32 famílias e 75 espécies. A maioria das espécies é zoocórica, dependentes de luz para germinação e formadoras de dossel, porém, a abundância de indivíduos revelou maior contribuição de indivíduos autocóricos, tolerantes à sombra e de sub-bosque. A densidade de M. multiramea elevou-se ao longo dos quatro anos após período reprodutivo (p&lt; 0,05), com aumento da altura média dos colmos (p&lt;0,01), mas sem alteração no número médio de colmos (p=0,46). Uma NPMANOVA revelou diferenças significativas entre composição e respectivas abundâncias entre os levantamentos, com maior similaridade entre as amostras de dois anos após o período reprodutivo de M. multiramea. Houve aumento da riqueza específica ao longo do tempo, estando diretamente associada à abundância de M. multiramea (p=0,002), porém, com diminuição da uniformidade de abundâncias entre espécies em regeneração.

Bird and Plant Diversity in Tropical Landscape Mosaics in East Usambaras, Tanzania

The role of land uses outside protected areas in conserving tropical biodiversity remains poorly understood and contested. This paper summarizes the results of plant and bird surveys conducted in three rural landscapes in the East Usambara Mountains of Tanzania, covering a gradient from Village forest reserves to tree-based and other agricultural land uses. The species richness and occurrence of conservationally important species across the land uses were analyzed. Twelve plots of 0.2 ha, stratified among land use types, were established to survey the large trees, with sub-plots of 1 × 40 m for tree saplings, shrubs and non-woody plants, and 5 × 40 m plots for small trees. Avian richness was measured in the same sites as the plants through mist netting and timed species counts. The village forests had higher plant species richness and more conservationally important plant species compared to other land uses. Agroforest and fallows supported a relatively high number of plant species, but the species composition was largely different to the adjacent village forests. Bird species of conservation importance were recorded across all land uses. Village forest reserves and some of the tree-based agricultural land uses were found to contribute to biodiversity conservation goals in tropical landscape mosaics. There is a need to better integrate them, and address their multiple functions, in village land-use planning and conservation efforts at the landscape level.

Effects of Land-Use Change on Under Storey Species Composition and Distribution in a Tropical Rainforest

The forest land’s conversion into tree crops plantations plays a major role in the loss of biodiversity. Therefore, understanding the impacts of land-use change on species diversity is very critical for ecosystem functioning and stability. This study was carried out to evaluate the effect of land-use changes on under storey species diversity in the Theobroma cacao and Citrus sinensis plantations. Two, 25 m × 25 m plots were sampled in each plantation and a nearby undisturbed secondary rainforest for comparison. The diameters (dbh-1.3 m) of all trees at breast height >10 cm were measured in each plot. Five line transect were systematically laid and a quadrat of 50 cm × 50 cm placed at every 1 m point to identify the under storey species (herbaceous, shrubs, tree saplings and climbers) present in each plot. Percentage canopy, species diversity using Shannon-Wiener, Simpson’s index and Evenness were determined, while species similarity was determined using the Jaccard’s similarity index. Results indicate that woody basal area and stem density in Theobroma cacao were significantly (P<0.05) higher than the Citrus sinensis plantation. A total number of 25, 27, and 14 under storey species distributed in 16, 19 and 11 families were found in Theobroma cacao , Citrus sinensis plantations and secondary forest respectively. Panicum maximum and Axonopus compressus were the dominant grasses in the Theobroma cacao and Citrus sinensis plantations respectively. The percentage canopy cover was significantly (P<0.05) higher in the secondary forest than the plantations. The land use modification has significantly increased the under storey species composition.

Lianas have a greater competitive effect than trees of similar biomass on tropical canopy trees

Lianas (woody vines) reduce growth and survival of host trees in both temperate and tropical forests; however, the relative strength of liana‐tree competition in comparison to tree‐tree competition remains unexplored. When controlling for biomass, lianas may have greater competitive effects than trees because the unique morphology of lianas allows them to reach the forest canopy at relatively small stem diameters and deploy a substantial crown above their host. We tested the hypothesis that lianas have a greater negative effect on canopy trees than do trees of similar biomass with a liana‐ and tree sapling‐cutting experiment in a seasonal tropical moist forest in Panama. The response of canopy trees to the cutting treatments was characterized as the change in their daily water use by measuring their sap velocity before and after cutting. We compared the responses of canopy trees around which a similar biomass of either lianas or tree saplings had been cut to control trees with no cutting. Liana cutting increased canopy‐tree sap velocity by ∼8% from before to after cutting relative to control trees during the dry season. In contrast, canopy‐tree sap velocity did not respond to tree cutting, probably because trees with biomass similar to lianas were confined to the forest understory. We observed a similar pattern of sap velocity changes during the wet season, but treatment differences were not significant. Our results demonstrate that release from liana competition, but not tree competition, resulted in increased water transport in canopy trees, and suggests that relative to their biomass, lianas have greater competitive effects on canopy tree performance than do competing trees.

Impact of tree saplings on the kinetic energy of rainfall—The importance of stand density, species identity and tree architecture in subtropical forests in China

In order to estimate the influence of plant architectural traits on the erosivity of throughfall we studied throughfall kinetic energy (KE) under tree saplings in a plantation-like experiment in the humid subtropics. Our analyses of rainfall and throughfall KE are based on measurements using calibrated splash cups. Two experiments were carried out, one focusing on density effects and the other testing for species-specific effects and effects of species mixtures. The major architectural traits were measured to characterize sapling morphology. Mixed effects models were used for statistical analysis. In both models, rainfall KE was identified as the most important effect on throughfall KE. Overall, rainfall KE per area was reduced by 59% below the canopy of the studied saplings. We found a significant effect of sapling density on throughfall KE. This is primarily due to the relation between free throughfall and released throughfall. As free throughfall possesses a far higher KE than released throughfall originating from saplings, lower sapling density results in higher total throughfall KE. We also showed that the influence of density on throughfall KE decreases with increasing sapling height due to lateral canopy growth of the saplings.Throughfall KE was significantly different among species. We attribute this to species-specific differences in crown architectural traits. These traits have opposite influence on throughfall KE and interact with each other. Depending on its magnitude, one crown trait can possibly superimpose contrary effects of others.

Effects of tree sapling diversity and nutrient addition on herb-layer invasibility in communities of subtropical species

Exotic species are assumed to alter ecosystem functioning. However, little is known of the relationships within vertically structured plant communities such as forests, where tree saplings interact with herbaceous species, especially in the early phases of succession. This relationship was tested in a common garden experiment which assessed the impacts on tree saplings and herbaceous species following nutrient addition and the introduction of exotic herb species. The experiment was established in South- East China using four broad-leaved tree species (Elaeocarpus decipiens, Schima superba, Castanea henryi and Quercus serrata) to study the relationships between tree sapling diversity, herb-layer productivity and invasibility. Tree saplings were planted in monoculture and in mixtures of two and four species. A full factorial design was applied, within which species composition was crossed with nutrient and exotic seed-addition treatments. The seed-addition treatment included mixtures of seeds from eight exotic herb species, and herb community attributes were assessed after a four month growing season. Results indicate that certain tree species negatively affect native as well as exotic herbs; however, the high productivity of native herbs had a stronger negative impact on exotic species than tree saplings. Nutrient addition increased the productivity of exotic herbs but had no effect on native herbs. Remarkably, exotic species introduction had a negative feedback effect on the growth of tree saplings, which highlights the potential of exotic herbs to diminish tree recruitment. Although tree saplings reduced invasive effects on the herb-layer during the earliest phase of forest succession, nutrient addition had a more profound and opposite effect on these invaders.

Impacts of rattan cane harvesting on vegetation structure and tree diversity of Conservation Forest in Buton, Indonesia

Lambusango Forest, Buton, Indonesia, is an example of the potential for conflict between forest conservation and long standing local extraction of Non-timber Forest Products (NTFPs), in this case rattan cane harvesting. This paper investigates the impacts of rattan harvesting on tree and understorey vegetation structure, species richness and diversity. Tree and understorey vegetation characteristics and soil and topographic variables were recorded in forest plots. Interviews with rattan harvesters recorded information on harvesting techniques and locations. The relationships between tree and understorey vegetation characteristics and soils, topography and rattan harvesting techniques were assessed with the multivariate ordination technique of Redundancy Analysis (RDA). Analysis of the relationships with rattan harvesting proximity and forest designation zone used Multivariate Analyses of Covariance (MANCOVA). Tree species richness and diversity are primarily affected by slope gradient and altitude, while tree size is affected mainly by soil chemical factors. Only a small part of the variation in tree structure measures can be attributed to the impacts of rattan cane harvesting. Stronger adverse effects on understorey vegetation density, including tree saplings and seedlings, were found. This is thought to be a case of rattan harvesting exacerbating the effects of competition between rattan plants and other understorey vegetation. Longer term monitoring of forest characteristics could provide stronger understanding of the impacts. However, rattan harvesting appears to have little effect on forest structure and diversity in Lambusango Forest, suggesting that relatively small scale NTFP extraction does not necessarily conflict with forest conservation.

Structure and Regeneration Patterns of Pinus nigra subsp. salzmannii Natural Forests: A Basic Knowledge for Adaptive Management in a Changing Climate

Since climate change projections contain many uncertainties and are normally unable to predict the direction and magnitude of change at the small scale needed by forest managers, some understanding about the functioning of the target forest should be obtained before a robust management strategy can be applied. Structure and regeneration patterns are related to key ecosystem processes which, on the other hand, can be modified by silvicultural treatments. In this research, the structure and recruitment dynamics of two stands with different histories of management were investigated in the southern limit of the range of Pinus nigra subsp. salzmannii (Southeast Spain). We described forest structure and facilitation effects by forest canopies and nurse shrubs, and quantified the processes affecting each stage of regeneration (dispersed seed, first year seedling and second year seedling) in different microhabitats. Forest structure was more complex in the stand scarcely influenced by human activities. Juniperus communis shrubs seemed to facilitate the establishment of tree saplings. Most seedlings died of desiccation during their first summer. At best, 190 out of 10,000 emerged seedlings survived the first summer. In light of these results, the possibilities of applying close-to-nature forestry in the study forests and other aspects of silviculture under a frame of adaptive forest management are discussed.

Landscape-scale relationships between the exotic invasive shrub Lantana camara and native plants in a tropical deciduous forest in southern India

Abstract:Understanding exotic–native plant relationships within the context of landscape-scale environmental factors such as rainfall, topography, disturbance and forest structure, is important for distinguishing the role of invasions in native plant community change. In this study, the relationship between Lantana camara invasion and native forest understorey vegetation was described after accounting for environmental influences. Rainfall, terrain slope, altitude and fire frequency were measured from GIS layers, and tree density, dry above-ground L. camara biomass, and native plant abundance and species richness were measured in nested plots (four 1 × 1-m plots for grass, tree seedlings and L. camara within one 5-m-radius plot for tree saplings and herbs and shrubs within one 10-m-radius plot for trees) at 80 locations distributed across Bandipur Tiger Reserve, a tropical deciduous forest in southern India. Relationships between environmental factors and L. camara abundance were described using a multiple regression. Further, the role of L. camara abundance in explaining residual variation in native vegetation, after accounting for environmental influences, was described using linear models. Lantana camara abundance decreased with increasing tree density, supporting the notion that it thrives in disturbed forest with fewer trees. Whereas native tree seedling and herb and shrub density showed no relationship to L. camara abundance, both tree sapling density and grass volume decreased under L. camara biomass exceeding 2 kg m−2. These data suggest that, by association with grass decline and decreased recruitment of tree saplings, L. camara may be linked to the gradual transition of these tropical deciduous forests into exotic-dominated shrubland, and overall native biodiversity loss.

The 2011 Swedish Supreme Court Ruling: A Turning Point for Saami Rights

In 1998 a lawsuit was filed at the Umea District Court, Sweden, by 120 landowners in Nordmaling against the three Saami villages of Ran, Vapsten and Umbyn. The complaint concerned the entitlements to lands in the territory of Nordmaling, owned by the plaintiffs but habitually accessed by the Saami as winter pasture for their reindeer. The question was whether the Saami villages fulfilled the legal requirements of use over rime and had the right to herd according to customary right. In 2006 the landowners lost their claims in the District Court, which ruled in favour of the Saami, establishing the Saami villages' customary fight in the disputed territories. The landowners appealed to the Court of Appeals in Ovre Norrland, but lost again in 2007. The case was then appealed to the third and highest legal instance, the Swedish Supreme Court, which reached its verdict on 27 April 2011, ending the 14-year-long legal process. The Supreme Court upheld the previous verdicts, ruling that the Saami reindeer herders are entitled to graze their animals in the territory of Nordmaling according to the principle of customary rights. This is the first major legal victory for the Saami after decades of defending their right to herd reindeer on privately owned lands. Had the three Saami villages lost access to these winter pastures, the herders would have had to choose either to stop their herding practices overall, or to reduce significantly the number of animals, putting at risk the survival of their livelihood and culture as pastoralists over the long term. Besides granting herding rights in Nordmaling to the herders of Ran, Vapsten and Umbyn, this final ruling provides important guidelines about Saami land rights more broadly. The court confirmed that customary fights form the strongest legal principle for herding rights on winter pastures, and defined herding rights as collective rights that apply to the whole Saami reindeer herding population, and cannot expire. These new legal guidelines represent a call for a redefinition of state responsibilities in these matters, as well as stronger political measures to understand and solve the periodical local conflicts between Saami herders and landowners. Legal Precedents to the Nordmaling Case The Saami victory in the Nordmaling case needs to be understood against the long list of similar cases that preceded it. The first major legal process where Saami villages claimed stronger rights to land and water was the Altevatn case, tried in the Norwegian Supreme Court and closed in 1968. In that instance, Swedish Saami herders obtained confirmation of their 'immemorial' land rights (sw. Urminnes havd) to summer grazing in parts of Norway. The Altevatn victory sparked a similar legal contest for land rights in Sweden, known as the Taxed Mountain case (sw. Skattefjallsmalet) which closed in 1981. The Saami asked for confirmation of their user rights and possibly even ownership rights Coased on 'immemorial right'), over specific contested northern territories that are used year-round for herding purposes. The Supreme Court ruled against the Saami claims, but confirmed that a nomadic population could acquire ownership rights to land and water through 'immemorial use', defined as occupation and use gained so far back in time that no one knows or can remember when their ancestors first came to be there. The ruling for the Taxed Mountain case also established that the burden of proof for immemorial right rests with the Saami and must be secured in court for each contested land area. The Saami have since been fighting for their rights to use lands for grazing through drawn-out and costly legal processes, which they have most often lost. In the 1990s a number of forest companies joined seven hundred landowners in a lawsuit against Saami herders in what came to be known as the Harjedalen case. The land owners claimed that the Saami lacked customary rights to herd their reindeer 'below' the border of the defined year-round grazing areas2 in the territory of Harjedalen, and accused the reindeer herds of damaging newly planted tree saplings. …

Lantana camara invasion in a heterogeneous landscape: patterns of spread and correlation with changes in native vegetation

The effects of invasive species on community structure remain under-investigated due to the lack of long-term data. Our objectives were to examine the correlation between Lantana camara L. invasion and native species abundance, distribution, diversity, and population structure, across different forest types in a heterogeneous landscape. We examined changes in native vegetation and L. camara between 1997 and 2008. We used existing vegetation data from 134 plots spread across the 540 km2 landscape from 1997 and re-censused these plots in 2008. We then examined the change in species richness, Shannon’s diversity, evenness, and population structure of native species from 1997 to 2008. We also examined the relationship between L. camara density and species richness, diversity, evenness, and population structure. The presence and abundance of L. camara increased dramatically from 1997 to 2008. L. camara occurred in 81% of plots by 2008, compared with only 41% of plots in 1997. Similarly, the mean density of L. camara increased almost fourfold from 1997 to 2008. This was accompanied by a change in native community structure. Species richness, diversity and evenness declined significantly in some forest types, and at the landscape scale. There were also changes in the population structure of native tree species, with reductions in the density of tree saplings, possibly due to competition with L. camara. We demonstrate the pervasive threat posed by L. camara to native vegetation at the scale of individual forest types, and at the larger landscape scale, in our study area. These changes have long-term consequences for forest structure and composition.

Overstory and understory vegetation interact to alter soil community composition and activity

To test if there is an interactive effect between tree and understory species on the soil microbial community (SMC), community level physiological profiles (CLPP) and soil micro-fauna. A replicate pot experiment with five sapling tree species (Betula pendula, Betula pubescens, Sorbus aucuparia, Quercus petraea and Pinus sylvestris) and a no-tree treatment with and without Calluna vulgaris was established. After 21 months samples were taken for phospholipid fatty acid (PLFA) analysis, CLPP and soil microfauna assessment. There was an interactive effect of tree species and Calluna on the SMC, CLPP and nematode densities. Calluna addition changed the SMC composition (increase in fungal PLFAs) and the CLPP (lower utilisation of most carbon sources but greater utilisation of phenolic acids). A multivariate test for homogeneity of dispersion showed that while Calluna addition resulted in the presence of an altered microbial composition, it did not result in there being less variability among the samples with Calluna than among the samples without Calluna. Sapling trees with Calluna present grew less well than trees without Calluna. Structural equation modelling showed that it is possible that Calluna had an indirect effect on the SMC via below-ground tree biomass as well as a direct effect. Interactions between trees and understory vegetation can impact on the composition of soil biota and their activity.

Individual‐based trait analyses reveal assembly patterns in tree sapling communities

AbstractQuestionAre trait‐convergence assembly patterns (TCAP) and/or trait‐divergence assembly patterns (TDAP) of tree sapling communities related to microhabitat gradients in forest patches? If so, which traits are related to such patterns? What are the niche mechanisms potentially responsible for community assembly?LocationGrassland–forest mosaic in Serra do Sudeste region, southern Brazil (ca. 30.8°S, 53.1°W).MethodsWe used individual‐based trait information of 1132 tree saplings in 40 plots along gradients of canopy openness and grazing intensity in forest patches in southern Brazil. We used a trait‐based approach, bypassing taxonomic identification, as a first assessment of sapling community assembly in forest patches.ResultsBoth TCAP and TDAP indicate niche mechanisms underlying assembly of tree sapling communities. Specific leaf area (SLA), mean leaf area (LA) and relative abundance of toothed leaf margin (TLM) maximized TCAP. SLA and TLM tended to increase under more closed canopies, whereas LA had higher values at intermediate canopy openness. SLA and LA maximized TDAP and tended to vary more in more closed canopies, whereas SLA and presence of spines, which also maximized TDAP, showed higher variation under lower grazing intensity.ConclusionThe taxon‐free approach was very useful to infer niche mechanisms of tree sapling assembly in forest patches. By adopting an individual‐based trait approach, we assumed that both intra‐specific and intra‐population trait variability were relevant for revealing assembly patterns. We highlight that the use of individual‐based trait data in a metacommunity framework is an excellent way to evaluate TCAP and TDAP at the metacommunity scale, since it takes into account the entire variation of traits throughout communities.