Structure and composition of altered riparian forests in an agricultural Amazonian landscape
Nagy, R. Chelsea
Quintino, Raimundo Mota
do Nascimento, Sebastiao Aviz
MetadataShow full item record
KeywordAgriculture; Amazon; Brazil; Composition; Diversity; Forest structure; Fragmentation; Riparian ecosystems
Deforestation and fragmentation influence the microclimate, vegetation structure, and composition of remaining patches of tropical forest. In the southern Amazon, at the frontier of cropland expansion, forests are converted and fragmented in a pattern that leaves standing riparian forests whose dimensions are mandated by the Brazilian National Forest Code. These altered riparian forests share many characteristics of well-studied upland forest fragments, but differ because they remain connected to larger areas of forest downstream, and because they may experience wetter soil conditions because reduction of forest cover in the surrounding watershed raises groundwater levels and increases stream runoff. We compared forest regeneration, structure, composition, and diversity in four areas of intact riparian forest and four areas each of narrow, medium, and wide altered riparian forests that have been surrounded by agriculture since the early 1980s. We found that seedling abundance was reduced by as much as 64% and sapling abundance was reduced by as much as 67% in altered compared to intact riparian forests. The most pronounced differences between altered and intact forest occurred near forest edges and within the narrowest sections of altered riparian forests. Woody plant species composition differed and diversity was reduced in altered forests compared to intact riparian forests. However, despite being fragmented for several decades, large woody plant biomass and carbon storage, the number of live or dead large woody plants, mortality rates, and the size distribution of woody plants did not differ significantly between altered and intact riparian forests. Thus, even in these relatively narrow forests with high edge : area ratios, we saw no evidence of the increases in mortality and declines in biomass that have been found in other tropical forest fragment studies. However, because of the changes in both species community and reduced regeneration, it is unclear how long this relative lack of change will be sustained. Additionally, Brazil recently passed a law in their National Forest Code allowing narrower riparian buffers than those studied here in restored areas, which could affect their long-term sustainability.
Author Posting. © Ecological Society of America, 2015. This article is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Ecological Applications 25 (2015): 1725-1838, doi:10.1890/14-1740.1.
Suggested CitationEcological Applications 25 (2015): 1725-1838
Showing items related by title, author, creator and subject.
Composition and carbon dynamics of forests in northeastern North America in a future, warmer world Mohan, Jacqueline E.; Cox, Roger M.; Iverson, Louis R. (NRC Research Press, 2009-02-13)Increasing temperatures, precipitation extremes, and other anthropogenic influences (pollutant deposition, increasing carbon dioxide) will influence future forest composition and productivity in the northeastern United ...
Variability in the carbon isotopic composition of foliage carbon pools (soluble carbohydrates, waxes) and respiration fluxes in southeastern U.S. pine forests Mortazavi, Behzad; Conte, Maureen H.; Chanton, Jeffrey P.; Weber, John C.; Martin, Timothy A.; Cropper, Wendell P. (American Geophysical Union, 2012-04-19)We measured the δ13C of assimilated carbon (foliage organic matter (δCOM), soluble carbohydrates (δCSC), and waxes (δCW)) and respiratory carbon (foliage (δCFR), soil (δCSR) and ecosystem 13CO2 (δCER)) for two years at ...
Soil warming alters nitrogen cycling in a New England forest : implications for ecosystem function and structure Butler, Sarah M.; Melillo, Jerry M.; Johnson, J. E.; Mohan, Jacqueline E.; Steudler, Paul A.; Lux, H.; Burrows, E.; Smith, R. M.; Vario, C. L.; Scott, Lindsay; Hill, T. D.; Aponte, N.; Bowl, F. (Springer, 2011-10-05)Global climate change is expected to affect terrestrial ecosystems in a variety of ways. Some of the more well-studied effects include the biogeochemical feedbacks to the climate system that can either increase or decrease ...