Spatial complexity in fragmenting Amazonian rainforests: Do feedbacks from edge effects push forests towards an ecological threshold?

Cumming, Graeme S.; Southworth, Jane; Rondon, Xanic J.; Marsik, Matthew

doi:10.1016/j.ecocom.2012.03.002

Cited by 29 publications

(29 citation statements)

References 65 publications

(73 reference statements)

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“…Significant attention has been drawn to areas of tropical forest cover, and specifically the Amazon region across the past few decades due to the alarming rates of clearing which have been occurring in the Amazon region [3][4][5][6][7][8][9][10][11][12][13]. Such losses have profound impacts on biodiversity, global carbon storage, potential future and current climate changes, all of which have significant impacts on the resilience of social-ecological systems [14]. As such, understanding the process of deforestation and the pattern of development is key in this critical ecosystem.…”

Section: Introductionmentioning

confidence: 99%

Remote Sensing-Based Fractal Analysis and Scale Dependence Associated with Forest Fragmentation in an Amazon Tri‑National Frontier

Sun

Southworth

2013

Remote Sensing

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Abstract:In the Amazon, the development and paving of roads connects regions and peoples, and over time can form dense and recursive networks, which often serve as nodes for continued development. These developed areas exhibit robust fractal structures that could potentially link their spatial patterns with deforestation processes. Fractal dimension is commonly used to describe the growth trajectory of such fractal structures and their spatial-filling capacities. Focusing on a tri-national frontier region, we applied a box-counting method to calculate the fractal dimension of the developed areas in the Peruvian state of Madre de Dios, Acre in Brazil, and the department of Pando in Bolivia, from 1986 through 2010. The results indicate that development has expanded in all three regions with declining forest cover over time, but with different patterns and rates in each country. Such differences were summarized within a proposed framework to indicate deforestation progress/level, which can be used to understand and regulate deforestation and its evolution in time. In addition, the role and influence of scale was also assessed, and we found local fractal dimensions are not invariant at different spatial scales and thus concluded such scale-dependent features of fragmentation patterns are here mainly shaped by the road paving.

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Section: Introductionmentioning

confidence: 99%

Remote Sensing-Based Fractal Analysis and Scale Dependence Associated with Forest Fragmentation in an Amazon Tri‑National Frontier

Sun

Southworth

2013

Remote Sensing

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“…From 1999 to 2010, the amount of understory area that burned within 500 m of a deforestation event ranged from 25 to 46 % during years with high deforestation rates (Morton et al 2013). Models suggest that fire amplifies edge effects in fragmented forest, accelerating degradation more rapidly than expected from fragmentation alone (Cumming et al 2012). The Xingu River headwaters region of Brazil that surrounds the present study site encompasses many of these factors.…”

Section: Introductionmentioning

confidence: 98%

Early recruitment responses to interactions between frequent fires, nutrients, and herbivory in the southern Amazon

et al. 2015

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Understanding tropical forest diversity is a long-standing challenge in ecology. With global change, it has become increasingly important to understand how anthropogenic and natural factors interact to determine diversity. Anthropogenic increases in fire frequency are among the global change variables affecting forest diversity and functioning, and seasonally dry forest of the southern Amazon is among the ecosystems most affected by such pressures. Studying how fire will impact forests in this region is therefore important for understanding ecosystem functioning and for designing effective conservation action. We report the results of an experiment in which we manipulated fire, nutrient availability, and herbivory. We measured the effects of these interacting factors on the regenerative capacity of the ecotone between humid Amazon forest and Brazilian savanna. Regeneration density, diversity, and community composition were severely altered by fire. Additions of P and N + P reduced losses of density and richness in the first year post-fire. Herbivory was most important just after germination. Diversity was positively correlated with herbivory in unburned forest, likely because fire reduced the number of reproductive individuals. This contrasts with earlier results from the same study system in which herbivory was related to increased diversity after fire. We documented a significant effect of fire frequency; diversity in triennially burned forest was more similar to that in unburned than in annually burned forest, and the community composition of triennially burned forest was intermediate between unburned and annually burned areas. Preventing frequent fires will therefore help reduce losses in diversity in the southern Amazon’s matrix of humanaltered landscapes

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“…Hentz, A. M. K. et al ISSN eletrônico 1982 10.5380/rf.v47i4.53551 luminosity and wind, increase of evapotranspiration which decreases the flux of water in the soil, changes in biomass decomposition and carbon liberation to the atmosphere (MURCIA, 1995;VASCONCELOS, 2009). Other than that, it is observed a higher intensity and occurrence of forest fires due to the proximity with non-forest areas, which were favored because of the presence of conditions as less moisture in the soil, as well the high intensity of sun light and winds that can spread the flames (CUMMING et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Edge Effect on a Tree Community in an Araucaria Forest Fragment in Brazil

Hentz

Corte

Sanquetta

et al. 2017

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The forest fragmentation is considered to be one of the main processes causing negative effects on biodiversity. Among its effects, it causes changes in the composition and diversity of forest species through the replacement of original species by other adapted for disturbance areas. Therefore, the objective of this research was to evaluate the impact of the edge effect over richness and abundance of tree species in an Araucaria Forest fragment in southern Brazil. Data from two plots of 1 hectare each submitted to annual inventories (since 1995) were used. Individuals with diameter at breast height (1.30 m) over 10 cm were measured, and their geographical coordinates were recorded. These individuals were plotted over a grid where the plots were divided into subplots of 10x100 m after the edge. In addition, the edge influence over mortality and ingrowth was assessed. The existence of influence over richness and abundance of tree individuals was observed, mainly in the region up to 30 m from the edge. The edge effect influences mainly the ingrowth in comparison to the mortality, and both plots responded differently to edge effects. Keywords: Forest fragmentation; Atlantic forest; floristic composition; ecological group; cluster analysis. Resumo Efeito de borda sobre uma comunidade arbórea em um fragmento de Floresta com Araucária no Brasil.A fragmentação das florestas é considerada um dos principais processos que causam efeitos negativos sobre a biodiversidade. Entre eles estão alterações na composição e diversidade de espécies florestais pela substituição de espécies originais por outras adaptadas a áreas de distúrbios. Dessa forma, o objetivo deste trabalho foi avaliar o impacto do efeito de borda sobre a riqueza e abundância de espécies arbóreas em um fragmento de Floresta com Araucária no sul do Brasil. Foram utilizados dados de duas parcelas de 1 hectare cada, coletados em inventários anuais (desde 1995). Os indivíduos com diâmetro à altura do peito (1,3 m) acima de 10 cm foram medidos, e suas coordenadas espaciais foram coletadas. Os indivíduos foram plotados em um grid de parcelas subdivididas em parcelas de 10x100 m após a borda. Além disso, o efeito de borda sobre o ingresso e mortalidade do indivíduo foi analisado. Também, foi observada a influência da borda sobre a riqueza e abundância de indivíduos, principalmente nos primeiros 30 m após a borda. O efeito de borda influenciou principalmente os ingressos, em comparação com a mortalidade, e as duas parcelas apresentaram diferentes respostas ao efeito de borda. Palavras-chave: Fragmentação florestal; Mata Atlântica; composição florestal; grupos ecológicos; Análise de Cluster.

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Spatial complexity in fragmenting Amazonian rainforests: Do feedbacks from edge effects push forests towards an ecological threshold?

Abstract: openAccessArticle: FalsePage Range: 67-67doi: 10.1016/j.ecocom.2012.03.002Harvest Date: 2016-01-12 15:11:21issueName:cover date: 2012-09-01pubType: Original Research Articl

Cited by 29 publications

References 65 publications

Remote Sensing-Based Fractal Analysis and Scale Dependence Associated with Forest Fragmentation in an Amazon Tri‑National Frontier

Remote Sensing-Based Fractal Analysis and Scale Dependence Associated with Forest Fragmentation in an Amazon Tri‑National Frontier

Early recruitment responses to interactions between frequent fires, nutrients, and herbivory in the southern Amazon

Edge Effect on a Tree Community in an Araucaria Forest Fragment in Brazil

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