Inferred causes of tree mortality in fragmented and intact Amazonian forests

D’Angelo, Sammya; Andrade, Ana; Laurance, Susan G.; Laurance, William F.; Mesquita, Rita

doi:10.1017/s0266467403001032

Cited by 93 publications

(49 citation statements)

References 32 publications

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“…O primeiro e o segundo eixo da PCA acumularam 55,4% e 32,1% da variância total, respectivamente. (Camargo & Kapos 1995) como resultado das altas taxas de mortalidade e danos às árvores (Ferreira & Laurance 1997;Laurance et al 1998a;D'Angelo et al 2004), favorece o estabelecimento e crescimento de espécies pioneiras e secundárias adaptadas às condições de alta luminosidade . Benitez-Malvido (1998) também demonstrou que a densidade de plântulas de espécies tardias declinou em locais próximos às bordas, indicando que o estabelecimento destas espécies vem diminuindo devido às condições diferenciadas relacionadas às áreas de borda.…”

Section: Discussionunclassified

Efeitos de borda sobre a vegetação e estruturação populacional em fragmentos de Cerradão no Sudoeste Goiano, Brasil

Lima‐Ribeiro

2008

Acta Bot. Bras.

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RESUMO -(Efeitos de borda sobre a vegetação e estruturação populacional em fragmentos de Cerradão no Sudoeste Goiano, Brasil). Efeitos de borda são modificações nos parâmetros físicos, químicos e biológicos observadas na área de contato do fragmento de vegetação com a matriz circundante. O objetivo desse estudo foi testar a hipótese de que os efeitos de borda afetam alguns parâmetros vegetacionais e populacional em fragmentos de Cerradão no município de Caiapônia, Goiás. Para isso, estudou-se a estrutura da vegetação, o padrão de distribuição espacial de Vernonia aurea Mart. ex DC. (Asteraceae) e as condições microclimáticas (temperatura do ar e do solo e umidade relativa do ar) em dois ambientes, borda e interior, de três fragmentos de Cerradão com diferentes tamanhos (1,5 ha; 9 ha e 35 ha). Os resultados mostraram uma nítida influência dos efeitos de borda em todos os parâmetros analisados, uma vez que a estrutura da vegetação, o nível de agregação dos indivíduos de V. aurea e os parâmetros microclimáticos foram diferentes entre o interior e a borda dos fragmentos analisados. Esses dados corroboram com outros estudos realizados em diferentes ecossistemas, indicando que a fragmentação dos habitats modifica a composição e estrutura da vegetação, a estrutura espacial e a dinâmica das populações vegetais e, conseqüentemente, animais, podendo levar à extinção de populações locais e redução da diversidade biológica.Palavras-chave: cerrado, fragmentação de habitat, efeitos de borda, estrutura vegetacional, distribuição espacial ABSTRACT -(Edge effects on vegetation and population structure in Cerradão fragments of Southwest Goiás, Brazil). Edge effects are modifications in the physical, chemical and biological parameters observed in areas of contact of forest fragment with the surrounding environment. This paper aimed to test the hypothesis that the edge effects influence some vegetation and population parameters in Cerradão fragments in Caiapônia County, Goiás. To this effect, vegetation structure, Vernonia aurea Mart. ex DC. (Asteraceae) spatial distribution and microclimate conditions (air and soil temperature and air humidity) were analyzed in two habitats, edge and interior, of three Cerradão fragments with different areas (1.5 ha, 9 ha, and 35 ha). The results showed a strong influence of edge effects on all parameters analyzed, that is, vegetation structure, V. aurea aggregation index and microclimate parameters were all different between interior and edge habitats. These results corroborate other studies conducted in different ecosystems, indicating that habitat fragmentation modifies vegetation structure and composition, plant population dynamics and spatial structure, and as a result, local biological diversity is reduced.

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Section: Discussionunclassified

Efeitos de borda sobre a vegetação e estruturação populacional em fragmentos de Cerradão no Sudoeste Goiano, Brasil

Lima‐Ribeiro

2008

Acta Bot. Bras.

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“…The second aspect is based on habitat heterogeneity, i.e., the heterogeneity within and among stands caused by disturbance and topography. Although this second aspect is considered a relevant surrogate of biodiversity [31], habitat fragmentation substantially reduces forest biomass [64], possibly due to enhanced tree mortality and the proliferation of disturbance-adapted species, such as lianas [65]. Moreover, basal area and tree height differ between hills and flat areas [27].…”

Section: Factors Related To Species Richness and Biomass Estimationsmentioning

confidence: 99%

Improving Species Diversity and Biomass Estimates of Tropical Dry Forests Using Airborne LiDAR

et al. 2014

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The spatial distribution of plant diversity and biomass informs management decisions to maintain biodiversity and carbon stocks in tropical forests. Optical remotely sensed data is often used for supporting such activities; however, it is difficult to estimate these variables in areas of high biomass. New technologies, such as airborne LiDAR, have been used to overcome such limitations. LiDAR has been increasingly used to map carbon stocks in tropical forests, but has rarely been used to estimate plant species diversity. In this study, we first evaluated the effect of using different plot sizes and plot designs on improving the prediction accuracy of species richness and biomass from LiDAR metrics using multiple linear regression. Second, we developed a general model to predict species richness and biomass from LiDAR metrics for two different types of tropical dry forest using regression analysis. Third, we evaluated the relative roles of vegetation structure and habitat heterogeneity in explaining the observed patterns of biodiversity and biomass, using variation partition analysis and LiDAR metrics. The results showed that with increasing plot size, there is an increase of the accuracy of biomass estimations. In contrast, for species richness, the inclusion of different habitat conditions (cluster of four plots over an area of 1.0 ha) provides better estimations. We also show that models of plant diversity and biomass can be derived from small footprint LiDAR at both local and regional scales. Finally, we found that a large portion of the variation in species richness can be exclusively attributed to habitat heterogeneity, while biomass was mainly explained by vegetation structure.

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“…In concert with increased desiccation and other microclimatic stresses near edges (Kapos 1989;Turton & Freiberger 1997), wind disturbance has been shown in some cases to cause sharply elevated tree mortality inside forests within approximately 100-500 m of forest edges (Fig. 2;Laurance 1991;Laurance et al 1998a;D'Angelo et al 2004; but see Pohlman et al 2008). Large (>60 cm diameter) trees in fragments appear especially vulnerable (Laurance et al 2000).…”

Section: Wind and Fragmented Forestsmentioning

confidence: 99%

Impacts of wind disturbance on fragmented tropical forests: A review and synthesis

2008

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Wind disturbance is an important ecological force in the tropics, especially in the cyclonic and hurricane zones from about 7-20°latitude. Damage from intense winds may be especially severe in fragmented forests because of their abrupt artificial margins and denuded surrounding landscapes. We review available information on the effects of windstorms on fragmented forests, synthesizing studies from Australasia, Amazonia and elsewhere in the tropics. Wind damage in fragmented landscapes can be influenced by a range of factors, such as forest-edge orientation, edge structure, the size of nearby clearings and local topography. We argue that wind disturbances are likely to interact with, and exacerbate, a range of deleterious environmental changes in fragmented forests. Among the most important of these are altered forest structure, shifts in plant species composition, exotic-plant invasions, reduced carbon storage and elevated vulnerability to fire.The damaging impacts of winds on fragmented forests could potentially increase in the future, particularly if global warming leads to increasingly severe or frequent windstorms.

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Inferred causes of tree mortality in fragmented and intact Amazonian forests

Cited by 93 publications

References 32 publications

Efeitos de borda sobre a vegetação e estruturação populacional em fragmentos de Cerradão no Sudoeste Goiano, Brasil

Efeitos de borda sobre a vegetação e estruturação populacional em fragmentos de Cerradão no Sudoeste Goiano, Brasil

Improving Species Diversity and Biomass Estimates of Tropical Dry Forests Using Airborne LiDAR

Impacts of wind disturbance on fragmented tropical forests: A review and synthesis

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