Consequences of suppressing natural vegetation in drainage areas for freshwater ecosystem conservation: considerations on the new "Brazilian forest code"

Abstract

The input of particulate and dissolved organic matter (POM and DOM, respectively) from terrestrial ecosystem drainage basins is an important energy and nutrient source in limnic food chains. Studies indicated that semi-deciduous seasonal forests located in drainage areas in Brazil have the potential to produce 7.5 - 10.3 Mg ha⁻¹/year of POM. The global increase in vegetation destruction, such as forests, threatens this allochthonous resource and can have significant impacts on river and lake communities and food chains. Therefore, it is critical that exploitation and occupation protocols are updated to protect the transition areas between terrestrial and limnic ecosystems. This review highlights the existing knowledge of these ecosystem interactions and proposes responsible sustainable methods for converting the vegetation in drainage basins. This was based on Brazilian ecosystem data and the new "Brazilian Forest Code." This study also considers the importance of including flood tracks in permanently protected areas to improve Brazilian legislation and protect hydric resources.

freshwater biodiversity; freshwater food chains; freshwater resources; riparian forests; watershed

Introduction

According to the United Nations GEO-5 report (United Nations Environment Programme 2012), the global loss in forest cover is occurring at an alarming rate. Although the deforestation rate decreased by approximately 3 million ha/year from 1990 (losses of 16 million ha/year) to 2000 (losses of 13 million ha/year), this is still an insufficient reduction. The destruction of forested areas, stimulated by economic exploitation and demographic expansion (Angelsen & Kaimowitz 1999), should be closely observed. In the past 50 years, a considerable loss of biodiversity and ecosystem impairment has been observed primarily because of non-sustainable agricultural practices (Tilman et al. 2002). Watershed vegetation provides an important energy and nutrient input in limnic ecosystems (Lampert & Sommer 2007) and will ultimately lead to its suppression when exploited (Naiman & Decamps 1997; Naiman et al. 2000; Aitkenhead-Peterson et al. 2003; Bertilsson & Jones 2003; Davies et al. 2008). This loss of vegetation threatens food chains through on-going eutrophication, chemical contamination, and sedimentation (Moss 2010).

In 2009, 3.3 and 1.5 billion hectares of land were occupied worldwide by pastures and fields, respectively, of which Latin America and the Caribbean accounted for 27% and 8.4%, respectively (United Nations Environment Programme 2012). Because of the suppression process in natural landscapes for the deployment of agroecosystems, Latin America and Africa were responsible for the highest rates of global deforestation. Brazil comes under increasing pressure from consumers for their commodities, and non-governmental organizations, with their policy for environmental protection, could contribute significantly to the reduction of illegal logging (United Nations Environment Programme 2012).

In this context, discussions prior to the approval of Law 12.651/12, which established the so-called new "Brazilian Forest Code," were marked by concerns from conservationists. They warned both civil and political societies about the likely threats to terrestrial and limnic ecosystems if developmental bias takes precedence over sustainability and the preservation of natural resources. These warnings, which were issued to legislators by researchers and specialists in the conservation of Brazilian natural resources, were motivated by the risks arising from a law that proposed to assure "the continuity of national agricultural development." This new legislation would regulate the exploitation of the forest ecosystem, define the extension of riparian and gallery forest cover, and influence the function of limnic ecosystems (Ramírez et al. 2008). According to Ab'Saber (2010), the new law may increase the human interference of natural ecosystems and biodiversity by permitting, for example, a reduction in riparian forest cover. The expansion of economic activities such as agriculture, livestock production, and logging that would be sanctioned by the new legislation could lead to considerable environmental impacts on limnic ecosystems and the species that are dependent upon them (Casatti 2010; Tundisi & Tundisi 2010; Magalhães et al. 2011; Ferreira et al. 2014).

The concerns of researchers and conservationists are clearly recognized when the losses of the original Brazilian vegetation cover that occurred prior to 2004 is examined. The Cerrado (Brazilian savanna), a highly threatened Brazilian biome and unique ecoregion, had lost 55% of its original area by 2004, and the Pantanal, a tropical wetland area, saw a 17% suppression of its vegetation (Machado et al. 2004; Harris et al. 2005; Carranza et al. 2014). The area occupied by savannah formations, primary and secondary forests, mangroves, and sandbank vegetation was reduced by 3.8 million hectares (SMA 2005) between 1962 and 2001 in the state of São Paulo alone. Some regions of Brazil have suffered large losses in vegetation cover because of the biofuel agribusiness, which flourishes to the detriment of natural ecosystems (Lewinsohn 2011). All of these recent losses in natural vegetation corroborate the concerns raised about environmental degradation by researchers and activists.

Importance of drainage basins

The vegetation of drainage basins and riparian forests is known for its role in maintaining local biodiversity (Turner et al. 2001) and acting as corridors for animal migration (Metzger 2010). Their influence on limnic bodies is also important through the deposition of particulate and dissolved organic matter (POM and DOM, respectively) and nutrients via mineralized accumulated litterfall (Naiman & Decamps 1997; Allan 2004; Moss 2010). POM and nutrients can be transported to these limnic bodies from distant areas by floods as well as by wind (Chapin et al. 2002; Baldock 2007; McNeill & Unkovich 2007). Watershed deforestation may lower the DOM and nutrient inflow into rivers, streams, and lakes (Lawton et al. 2001). This decrease in nutrients such as nitrogen (N), phosphorus (P), silicon, and organic carbon modifies the chemical composition of the water, thereby influencing food chains and leading to a decrease in primary limnic productivity (Neill et al. 2001; Aitkenhead-Peterson et al. 2003; Lampert & Sommer 2007).

An equally important function performed by riparian forests is the sequestration of stress agents such as pesticides and fertilizers that come from adjacent agricultural areas (Vaithiyanathan & Correll 1992; Schönborn 2003; Sweeney et al. 2004; Wantzen et al. 2008; Gücker et al. 2009). The riparian forests reduce the harmful disturbance of those stressors on biotic components, maintains limnic body function (Allan 2004; Ramírez et al. 2008; Winemiller et al. 2008), and maintains the edaphic water percolation that occurs at the margins of rivers and streams (Sternberg 1987). Despite their importance, riparian forests and vegetation in drainage basins are still suffering from deforestation, particularly in tropical regions (Pinay et al.1990; Barrela et al. 2000).

Natural vegetation suppression in drainage basins can change the chemical characteristics of rivers and streams (Fig. 1; Ramírez et al. 2008). Phytoplankton productivity is also affected (Phlips et al. 2000) because a lack of tree cover increases solar radiation and water temperatures (Allan 2004). Waterways in deforested areas have significantly decreased levels of nutrients and organic matter (França et al. 2009), which influences the structure of limnic habitats and food chains (Araújo-Lima et al. 1986; Junk et al. 1989; Loverde-Oliveira & Huszar 2007). This interferes with the physiology of invertebrates (Bilby & Likens 1980) and fish (Maia & Chalco 2002; Gomiero et al. 2007), particularly in smaller rivers (Vannote et al. 1980). In addition, large-scale removal of natural vegetation in flood areas could represent a considerable impact not only on the biota of these plant formations but also on the communities found within limnic bodies. The black water rivers of the Amazon basin, for example, are darkened by the presence of humic compounds (Leenheer 1980; Moreira-Turcq et al. 2003). However, the marked deforestation of local drainage areas interfere directly with DOM input (Sombroek 2000; Moss 2010), thereby reducing the dark color of the water. The dependency of aquatic communities on allochthonous nutrients and energy (Henderson & Walker 1986) makes them vulnerable to deforestation.

Figure 1.
View of the Tijuco River (18°56'34"S 49°26'54"W), Ituiutaba municipality, Minas Gerais state, Brazil. Note the accumulation of sediments in the river as a result of deforestation of riparian forest and slope vegetation.

The society must consider the disturbance that vegetation suppression will have on endemic species such as the cichlid Apistogramma pertensis (Haseman, 1911). This fish is found in Amazon rivers such as the Negro and Tefé that have a high concentration of DOM (humic acids) (Kullander & Ferreira 2005). Increased deforestation will alter the characteristics of these trophic niches in dark water Amazon rivers (Henderson & Walker 1986) and will have a significant impact on the numerous specialized biota associated with these habitats (Wantzen et al. 2008). In regions where clear water rivers are typical, such as the Atlantic forest, many endemic fish species such as Deuterodon iguape (Eigenmann 1907), Imparfinis piperatus (Eigenmann & Norris 1900), and Hollandichthys multifasciatus (Eigenmann & Norris 1900) are sensitive to human intrusion (Esteves & Lobón-Cerviá 2001) and may suffer if vegetation loss results in a decrease in allochthonous food resources.

The scarcity of information of the interactions between tropical terrestrial and limnic ecosystems (Wantzen et al. 2008), as observed in the Atlantic and Amazon forests and other Brazilian biomes (Ab'Saber 2010), coupled with the rapid expansion of global exploitation of natural resources and the consequential suppression of plants (United Nations Environment Programme 2012) prompted this review. In the following sections, we discuss the potential consequences to riverine environments associated with reduced vegetation cover in drainage basins, thus highlighting the problems related to limnic biota preservation (Ramírez et al. 2008). Moreover, we propose criteria for valley occupation protocols by focusing on vegetated areas that are subject to flooding, thus emphasizing a Brazilian case study.

Our review was based on the practical experience and knowledge of the authors as well as published scientific data available from various databases. The objective was to address the theme of ecological changes to limnic environments and the consequences caused by a reduction of vegetation cover in drainage basins. In addition, we used this information as a basis for discussing the importance of floodplain protection as a fundamental practice during the occupation of drainage areas for agricultural and livestock activities.

Drainage basins and nutrient input

The flood pulse concept (Junk et al. 1989) predicted the transport of POM, DOM, and nutrients from inundated areas into limnic compartments, which were influenced by a number of factors, including soil and vegetation characteristics, rainfall variation, and relief (Tockner et al. 2000). The methods and protocols by which valley bottoms are occupied with agricultural and silvicultural activities should prioritize sustainability when their management protocols are designed. For example, in areas occupied by plains (regions with a low slope), plant formations located beyond the riparian forest but within the river floodplain may be potential sources of energy and nutrients for a limnic system, i.e. they contribute to system function and maintenance of its food chains. To fully understand these functions, differences in litter production and decomposition rates between forest and savannah formations must be understood. Tropical forests often accumulate greater annual quantities of litterfall than savannahs (Tab. 1). This greater litter volume decomposes over relatively short periods, and the high decomposition rate (k) (Olson 1963; Morellato 1992; Cunha et al. 1993; Backes et al. 2005) corresponds to infra-annual periods. One may conclude that high decomposition rates in tropical forests define these litterfalls as important sources of DOM and nutrients. Conversely, the litter produced in savannahs often remains on the soil without decomposing for years at a time (Cianciaruso et al. 2006; Valenti et al. 2008). Thus, savannah formations adjacent to riparian forests and within inundated areas may supply limnic bodies with large quantities of POM, which is composed mainly of leaves with a large quantity of recalcitrant material such as lignin and cellulose (Bourlière & Hadley 1970; Coutinho 1990).

The Cerrado (Brazilian savannah) comprises tropical vegetation composed of different vegetation types that are frequently found on dystrophic soils (Oliveira-Filho & Ratter 2002). One edaphic feature of the Cerradois the low availability of soil nutrients. According to the hypothesis of "oligotrophic scleromorphism" (Arens 1958; Coutinho 1990), this could produce plant structures with recalcitrant characteristics, such as leaves and twigs that are more rigid from lignin and cellulose accumulation. The slow litter decomposition in Cerrado limnic bodies (Gonçalves et al. 2007) favors leaf accumulation on the bottom of lotic and lentic systems (Tockner et al. 2000) because POM is being continuously deposited (Moretti et al. 2009). This environment benefits detritivores (Wantzen & Wagner 2006), and limnic disturbance may interfere with the biota diversity (Lampert & Sommer 2007; Jacobsen et al. 2008). Aquatic organisms show a variety of feeding preferences, and they have adapted to the low nutritional value of this accumulated litterfall (Graça & Canhoto 2006). For example, insect and crustacean larvae are stimulated by nutritional quality, abundance, and chemical characteristics of POM when searching for food (Rincón & Martínez 2006; Janke & Trivinho-Strixino 2007; Moretti et al. 2009; Wood et al. 2012). Therefore, the chemical composition of the litterfall influences aquatic food chains because nitrogen concentration varies and there are limited nutrients for phytoplankton productivity (Hecky & Kilham 1988; Vitousek & Howarth 199l; Garnier 2004).

Influence of different vegetation types

The N:P ratio of the various vegetation types (Tab. 1) differs under the influence of both biotic and abiotic factors, such as the nutrient use strategies of different plant species (McGroddy et al. 2004) and soil features such as texture (Vasconcelos & Luizão 2004). Thus, it may be presumed that these formations will interfere with the evolutionary processes of limnic communities. In general, terrestrial systems provide a limited source of nutrients for limnic bodies (Moss 2010), supplying just enough nutrients to maintain limnic food chains.

Table 1.
Production of particulate organic matter (POM) or total litterfall, nitrogen (N) and phosphorus (P) levels, and respective N:P ratios in several regions of Brazil. Values are in mg ha-1/year. Vegetation formation (VF) is as follows: semi-deciduous seasonal forest (sf), dense ombrophilous forest (of), gallery forest (gf), and cerrado (cd).

POM	N	P	N:P	VF	Sites	References
10.3	0.21	0.01	21	sf	Pantanal, MT	(Haase 1999)*
9.40	0.18	0.01	18	sf	São Paulo, SP	(Meguro et al. 1979)
9.28	0.12	0.07	2	of	Maracá, AM	(Scott et al. 1992)
8.76	0.13	0.01	13	gf	Pantanal, MT	(Haase 1999)#
8.64	0.19	0.007	27	sf	Rio Claro, SP	(Pagano 1989a; Pagano 1989b)
8.30	0.15	0.003	50	of	Manaus, AM	(Luizão 1989)
8.04	0.11	0.003	37	of	Capitão Poço, PA	(Dantas & Phillipson 1989)
7.47	0.14	0.01	14	sf	Pantanal, MT	(Haase 1999)
7.01	0.16	0.01	16	of	Santo André, SP	(Domingos et al. 1997)
6.31	0.1	0.004	25	of	Ilha do Cardoso, SP	(Moraes et al. 1999)
5.04	0.07	0.004	17	of	Capitão Poço, PA	(Dantas & Phillipson 1989)
4.86	0.06	0.005	12	cd	Pantanal, MT	(Haase 1999)

• Plots 3FE*; 1FE#; 7NS‡; 5ND ; primary forest ; secondary forest

Evolutionary responses to various food sources define feeding niches (Pianka 2000). Therefore, changes in the quality of available food may considerably affect limnic food chains and communities. A number of factors, including temperature and variation in rainfall, influence the production and decomposition of plant matter. The example below demonstrates the significant environmental impact that vegetation suppression in river basins can have on limnic food chains. The clearing of a 100 ha of semi-deciduous seasonal forest led to an annual decrease of 1030 mg of POM, 210 mg of N, and 1 mg of P from the soil compartment [Tab. 1; Haase 1999]. When this forest patch flooded, the loss of these nutrients and POM greatly affected the associated limnic system and interfered with the dynamics of the aquatic trophic chain.

The reforestation of natural vegetation in floodplains beyond the riparian vegetation with species used in agricultural or forestry activities can also significantly impact aquatic biota not only through the reduction of accumulated litterfall but also by changing the chemical quality of the litterfall produced by the anthropogenic ecosystems. Many agricultural and forestry ecosystems produce smaller amounts of litter than natural ecosystems. Moreover, the plant biomass deposited on the agroforestry ecosystems soil is lower in nitrogen and phosphorus concentrations. This is an ecological disturbance to freshwater food chains because of the lower nutrient input that is necessary to sustain biota longevity. An exception was the cultivation of pearl millet Pennisetum glaucum (L.) (Boer et al. 2007) that showed the amount of POM produced in 100 hectares equaled 1080 mg, and 12 mg to N and 2 mg to P (Tab. 2). These values were similar to those observed in some natural ecosystems (Tab. 1). Nevertheless, values for gum Eucalyptus dunnii (Maiden) (Corrêa et al. 2013) and loblolly pine Pinus taeda (L.) reforestations (Schumacher et al. 2008) indicated that these values were still below those observed in natural ecosystems, particularly N (0.03 mg.ha⁻¹⁾ for both tree species.

Table 2.
Production of particulate organic matter (POM) or total litter and nutrient (N, P) soil input by litterfall deposition in agroforestry ecosystems in different regions of Brazil. Notations: nitrogen (N), phosphorus (P) levels, and respective N:P ratios in several agroforestry ecosystems (AF) of different regions of Brazil. Values are in Mg ha-1/year. Abbreviated genera: Eucalyptus, Pinus.

POM	N	P	N:P	AF	Sites	References
7.8	0.16	0.01	16	Sabia	Itambé, PE	(Ferreira et al. 2007)
5.8	0.1	0.003	33	Black-wattle	Butiá, RS	(Schumacher et al. 2003)
10.2	0.07	0.003	23	E. grandis	Bofete, SP	(Kolm & Poggiani 2003)
4.1	0.03	0.001	30	E. dunnii	Alegrete, RS	(Corrêa et al. 2013)
-	0.02	0.001	20	E. saligna	Itatinga, SP	(Câmara et al. 2000)
-	0.01	0.001	10	P. taeda	Cambará do Sul, RS	(Viera & Schumacher 2010)
4.5	0.03	0.002	15	P. taeda	Cambará do Sul, RS	(Schumacher et al. 2008)
5.9	0.1	0.007	14	Cocoa	Itajuípe, BA	(Fontes et al. 2014)1
4.6	0.08	0.006	13	Cocoa	Itajuípe, BA	(Fontes et al. 2014)2
10.8	0.12	0.02	6	Pearl millet	Rio Verde, GO	(Boer et al. 2007)
8.7	0.13	0,02	6	Finger millet	Rio Verde, GO	(Boer et al. 2007)
2.9	0.05	0.007	7	Amaranthus	Rio Verde, GO	(Boer et al. 2007)

• ¹
  Cocoa under natural vegetation (cabruca);
• ²
  Cocoa under Erythrina glauca as vegetation cover.

The chemical characteristics of litterfall produced by pine species Pinus (L.) reflects high levels of organic compounds that result in decomposition difficulty (Barnes et al. 1997) and very low decomposition rates (Olson 1963). Therefore, the time required for complete needleleaf decomposition would be considerably higher than the decomposition rates of litter accumulated in tropical forests. This information suggests that the replacement of natural vegetation formations, present in rivers and streams subject to flooding, with species used in agricultural or forestry activities over the years, interferes considerably with biota longevity and limnic food chains.

Protocol improvement: the Brazilian case

The so-called permanent protection areas of Brazil (Áreas de Proteção Permanente [APP]) were first created in the Forest Code of 1965 (Law 4.771/65) and included vegetation areas on the margins of Brazilian lakes and rivers. The size of these protected areas was based on the size of the limnic bodies themselves. A recent paper by Metzger (2010) corroborated the criteria and parameters used by this law; however, an increase in the size of some protected areas is required.

Neither the old nor the new law considered important characteristics such as the slope of the river body margins. However, the flood pulse concept (Junk et al. 1989) showed that the relief of water margins was one of the most important factors in determining the flooding extent (Tockner et al. 2000). Therefore, the slope of areas close to limnic bodies and the extent of the inundations are important factors that determine erosion and sedimentation risks. The slope profile also influences the amount of POM, DOM, and nutrients that make their way into limnic bodies.

Vegetation located beyond the riverine forests may strongly contribute to the transport of organic material into limnic bodies (Richey et al. 1990). The legislation that regulates the size and exploitation of riparian forests must not only consider the extent of the marginal areas but also the factors that influence the flood pulse (relief of the terrain), extent of the river basins, and soil characteristics. The protocols adopted by the new "Brazilian Forest Code" should be modified based on these considerations to guarantee an unaffected interaction between terrestrial and limnic ecosystems and facilitate the survival of plant and animal species therein.

Ensuring input continuity

Because of the highly complex nature of ecosystem interactions considered in this study (Junk et al. 2014), the above proposition may sound overly simplistic (Palmer & Febria 2012; Woodward et al. 2012). However, including the described topographic approach would increase the number of parameters currently considered by the Brazilian law. Moreover, other factors that also influence POM and DOM inputs into limnic bodies, such as soil and chemical characteristics, ground slope, and inundation level, would be used to decide the occupation of valley bottoms. In order for the proposed changes to be effective (Woodward et al. 2012), their application in different Brazilian rural communities must be feasible.

A continuous supply of POM, DOM, and nutrients from the vegetation of drainage basins must be protected for Brazilian waterways. Thus, the current "Brazilian Forest Code" should adopt an additional extension method that considers flood pulses. The protection of additional vegetation strips is essential to guarantee the on-going transport of energy and nutrients into limnic ecosystems because inundations can extend beyond the limits established by the present law. Variations in production periods and flood strength occur, thereby making it difficult to quantify these inputs (Wantzen et al. 2008). However, an understanding of their transport patterns into limnic bodies will provide indispensable information on the influence that vegetation in drainage areas has on the functioning of limnic ecosystems.

Final considerations

The influx of POM, DOM, and nutrients into limnic systems from the accumulated litterfall and decomposition in drainage areas varies in intensity and duration. These characteristics should be considered in proposals for the management of valley bottoms. If the law adopted an addition to the riparian strips to include those areas affected by annual floods as defined by slope relief, this single measure would significantly promote aquatic food chain permanence and biodiversity. In addition, there would be benefits to terrestrial ecosystems through the protection of unique forest formations. Furthermore, ecological corridors could be more easily implemented in regions heavily deforested by the expansion of agribusiness activities.

Reforestation costs by implementing the principles that we stand for could be circumvented in two ways: (1) allowing natural re-vegetation, thus ensuring that the seed bank or allochthonous propagules can help in the recovery of suppressed vegetation; and (2) simple land protection by adding them to the APP strips and renouncing some of the taxes paid by landowners. There are possibilities where new areas to be added to the respective APP's would cover many hectares. This strategy could bring a considerably reduced economic gain to the owners through the decrease of arable land or pastures. In these cases, we suggest that the services provided by the interaction between terrestrial and limnic ecosystems are calculated and reverted to the owners who had already planted the areas and reduced grazing.

Acknowledgements

The authors would like to thank the Federal University of Uberlândia and the Federal University of Mato Grosso for their logistic and financial support. Thanks are equally due to the National Council for Scientific and Technological Development (CNPq), the Minas Gerais State Research Foundation (FAPEMIG), and the Laboratory of Ecosystem Studies of the Cerrado Domain (LEDC).

References

• Ab'Saber AN. 2010. Do código florestal para o código da biodiversidade. Biota Neotropica 10: 331-335.
• Aitkenhead-Peterson JA, McDowell WH, Neff JC. 2003. Sources, production, and regulation of allochthonous dissolved organic matter inputs to surface waters. In: Findlay SEG, Sinsabaugh RL. (eds.) Aquatic ecosystems: interactivity of dissolved organic matter. San Diego, Academic Press. p. 25-70.
• Allan JD. 2004. Landscapes and riverscapes: the influence of land use on stream ecosystems. Annual Review of Ecology, Evolution, and Systematics 35: 257-284.
• Angelsen A, Kaimowitz D. 1999. Rethinking the causes of deforestation: lessons from economic models. The World Bank Research Observer 14: 73-8.
• Araújo-Lima CARM, Forsberg BR, Victoria R, Martinelli L. 1986. Energy sources for detritivorous fishes in the Amazon. Science 234: 1256-1258.
• Arens, K. 1958. O cerrado como vegetação oligotrófica. Boletim da Faculdade de Filosofia, Ciências e Letras da Universidade de São Paulo 224 Botânica 15: 59-77.
• Backes A, Prates FL, Viola MG. 2005. Produção de serapilheira em floresta ombrófila mista, em São Francisco de Paula, Rio Grande do Sul, Brasil. Acta Botanica Brasilica 19: 155-160.
• Baldock JA. 2007. Composition and cycling of organic carbon in soil. In: Marschner P, Rengel Z. (eds.) Nutrient cycling in terrestrial ecosystems. Soil biology. Heidelberg, Springer-Verlag Berlin. p. 1-35.
• Barnes BV, Zak DR, Denton SR, Spurr SH. 1997. Forest ecology. New York, John Willey & Sons Inc.
• Barrela W, Petrele Jr M, Smith WS, Montag FA. 2000. As relações entre as matas ciliares, os rios e os peixes. In: Rodrigues RR, Leitão Filho HF. (eds.) Matas ciliares: conservação e recuperação. São Paulo, Editora da Universidade de São Paulo, FAPESP. p. 187-207.
• Bertilsson S, Jones JB. 2003. Supply of dissolved organic matter to aquatic ecosystems: Autochthonous sources. In: Findlay SEG, Sinsabaugh RL. (eds.) Aquatic ecosystems: interactivity of dissolved organic matter. San Diego, Academic Press. p. 3-24.
• Bilby RE, Likens GE. 1980. Importance of organic debris dams in the structure and function of stream ecosystems. Ecology 61: 1107-1113.
• Boer CA, Assis RL, Silva GP, et al. 2007. Ciclagem de nutrientes por plantas de cobertura na entressafra em um solo de cerrado. Pesquisa Agropecuária Brasileira 42: 1269-1276.
• Bourlière F, Hadley M. 1970. The ecology of tropical savannas. Annual Review of Ecology and Systematics 1: 125-152.
• Câmara CD, Lima WP, Vieira SA. 2000. Corte raso de uma plantação de Eucalyptus saligna de 50 anos: impactos sobre a ciclagem de nutrientes em uma microbacia experimental. Scientia Forestalis 57: 99-109.
• Carranza T, Balmford A, Kapos V, Manica A. 2014. Protected Area Effectiveness in Reducing Conversion in a Rapidly Vanishing Ecosystem: The Brazilian Cerrado. Conservation Letters 7: 216-223.
• Casatti L. 2010. Alterações no código florestal brasileiro: impactos potenciais sobre a ictiofauna. Biota Neotropica 10: 31-34.
• Chapin FS III, Matson PA, Mooney HA. 2002. Principles of terrestrial ecosystem ecology. New York, Springer.
• Cianciaruso MV, Pires JSR, Delitti WBC, Silva EFLP. 2006. Produção de serapilheira e decomposição do material foliar em um cerradão na Estação Ecológica de Jataí, município de Luiz Antônio, SP, Brasil. Acta Botanica Brasilica 20: 49-59.
• Corrêa RS, Schumacher MV, Momolli DR. 2013. Deposição de serapilheira e macronutrientes em povoamento de Eucalyptus dunnii Maiden sobre pastagem natural degradada no Bioma Pampa. Scientia Florestalis 41: 65-74.
• Coutinho LM. 1990. Fire in the ecology of the Brazilian cerrado. In: Goldammer JG. (ed.) Fire in the tropical biota. Berlin, Springer-Verlag. p. 81-105.
• Cunha GC, Grendene LA, Durlo MA, Bressan DA. 1993. Dinâmica nutricional em floresta estacional decidual com ênfase aos minerais provenientes da deposição da serapilheira. Ciência Florestal 3: 35-64.
• Dantas M, Phillipson J. 1989. Litterfall and litter nutrient content in primary and secondary Amazonian 'terra firme' rain forest. Journal of Tropical Ecology 5: 27-36.
• Davies PM, Bunn SE, Hamilton SK. 2008. Primary production in tropical streams and rivers. In: Dudgeon D. (ed.) Tropical stream ecology. London, Academic Press. p. 23-42.
• Domingos M, Moraes RM, Vuono YS, Anselmo CE. 1997. Produção de serapilheira e retorno de nutrientes em um trecho de Mata Atlântica secundária, na Reserva Biológica de Paranapiacaba, SP. Revista Brasileira de Botânica 20: 91-96.
• Esteves KE, Lobón-Cerviá J. 2001. Composition and trophic structure of a fish community of a clear water Atlantic rainforest stream in southeastern Brazil. Environmental Biology of Fishes 62: 429-440.
• Ferreira J, Aragão LEOC, Barlow J, et al. 2014. Brazil's environmental leadership at risk. Science 346: 706-707.
• Ferreira RLC, Lira Junior MA, Rocha MS, Santos MVF, Lira MA, Barreto LP. 2007. Deposição e acúmulo de matéria seca e nutrientes em serapilheira em um bosque de sabiá (Mimosa caesalpiniifolia Benth.). Revista Árvore 31: 7-12.
• Fontes AG, Gama-Rodrigues AC, Gama-Rodrigues EF, Sales MVS, Costa MG, Machado RCR. 2014. Nutrient stocks in litterfall and litter in cocoa agroforests in Brazil. Plant and Soil 383: 313-335.
• França JS, Gregório RS, Paula JD, Gonçalves Jr JF, Ferreira FA, Callisto M. 2009. Composition and dynamics of allochthonous organic matter inputs and benthic stock in a Brazilian stream. Marine and Freshwater Research 60: 990-998.
• Garnier J. 2004. Drainage basin use and nutrient supply by rivers to the coastal zone. A modelling approach to the Seine river. In: Wassmann P, Olli K. (eds.) Drainage basin nutrient inputs and eutrophication: an integrated approach. Tromsø, University of Tromsø. p. 60-87.
• Gomiero LM, Carmassi AL, Braga FMS. 2007. Crescimento e mortalidade de Brycon opalinus (Characiformes, Characidae) no Parque Estadual da Serra do Mar, Mata Atlântica, estado de São Paulo. Biota Neotropica 7: 21-26.
• Gonçalves JF, Graça MAS, Callisto M. 2007. Litter decomposition in a cerrado savannah stream is retarded by leaf toughness, low dissolved nutrients and a low density of shredders. Freshwater Biology 52: 1440-1451.
• Graça MAS, Canhoto C. 2006. Leaf litter processing in low order streams. Limnetica 25:1-10.
• Gücker B, Boëchat IG, Giani A. 2009. Impacts of agricultural land use on ecosystem structure and whole-stream metabolism of tropical cerrado streams. Freshwater Biology 54: 2069-2085.
• Haase R. 1999. Litterfall and nutrient return in seasonally flooded and non-flooded forest of the Pantanal, Mato Grosso, Brazil. Forest Ecology and Management 117: 129-147.
• Harris MB, Arcangelo C, Pinto ECT, Camargo G, Ramos Neto MB, Silva SM. 2005. Estimativa de perda da área natural da Bacia do Alto Paraguai e pantanal brasileiro. Brasília, Conservação Internacional.
• Hecky RE, Kilham P. 1988. Nutrient limitation of phytoplankton in freshwater and marine environments: A review of recent evidence on the effects of enrichment. Limnology and Oceanography 33: 196-822.
• Henderson PA, Walker I. 1986. On the leaf litter community of the Amazonian blackwater stream Tarumazinho. Journal of Tropical Ecology 2: 1-16.
• Jacobsen D, Cressa C, Mathooko JM, Dudgeon D. 2008. Macroinvertebrates: composition, life histories and production. In: Dudgeon D. (ed.) Tropical stream ecology. London, Academic Press. p. 65-105.
• Janke H, Trivinho-Strixino S. 2007. Colonization of leaf litter by aquatic macroinvertebrates: a study in a low order tropical stream. Acta Limnologica Brasiliensia 19: 109-115.
• Junk WJ, Bayley PB, Sparks RE. 1989. The flood pulse concept in river-floodplain systems. Canadian Special Publication of Fisheries and Aquatic Sciences 106: 110-127.
• Junk WJ, Piedade MTF, Lourival R, et al. 2014. Brazilian wetlands: their definition, delineation, and classification for research, sustainable management, and protection. Aquatic Conservation: Marine and Freshwater Ecosystems 24: 5-22.
• Kolm L, Poggiani F. 2003. Ciclagem de nutrientes em povoamentos de Eucalyptus grandis submetidos à prática de desbastes progressivos. Scientia Forestalis 63: 79-93.
• Kullander SO, Ferreira EJG. 2005. Two new species of Apistogramma Regan (Teleostei: Cichlidae) from the rio Trombetas, Pará State, Brazil. Neotropical Ichthyology 3: 361-371.
• Lampert W, Sommer U. 2007. Limnoecology. New York, Oxford University Press.
• Lawton RO, Nair US, Pielke Sr RA, Welch RM. 2001. Climatic impact of tropical lowland deforestation on nearby Montane cloud forests. Science 294: 584-587.
• Leenheer JA. 1980. Origin and nature of humic substances in the Waters of the Amazon river basin. Acta Amazonica 10: 513-526.
• Lewinsohn TM. 2011. Forest loss began before bioethanol. Nature 469: 299.
• Loverde-Oliveira SM, Huszar VLM. 2007. Phytoplankton ecological responses to the flood pulse in a Pantanal lake, Central Brazil. Acta Limnologica Brasiliensia 19: 117-130.
• Luizão FJ. 1989. Litter production and mineral element input to the forest floor in central Amazonian forest. GeoJournal 19: 407-417.
• Machado RB, Ramos Neto MB, Pereira PGP, et al. 2004. Estimativas de perda da área do cerrado brasileiro. Brasília, Conservação Internacional.
• Magalhães ALB, Casatti L, Vitule JRS. 2011. Alterações no Código Florestal Brasileiro Favorecerão Espécies Não-nativas de Peixes de Água Doce. Natureza & Conservação 9:121-124.
• Maia LA, Chalco FP. 2002. Produção de frutos de espécies da floresta de várzea da Amazônia Central importantes na alimentação de peixes. Acta Amazonica 32: 45-54.
• McGroddy ME, Daufresne T, Hedin LO. 2004. Scaling of c:n:p stoichiometry in forests worldwide: implications of terrestrial redfield-type ratios. Ecology 85: 2390-2401.
• McNeill A, Unkovich M. 2007. The nitrogen cycle in terrestrial ecosystems. In: Marschner P, Rengel Z. (eds.) Nutrient cycling in terrestrial ecosystems. Soil biology. Berlin, Heidelberg, Springer-Verlag. p. 37-64.
• Meguro M, Vinueza GN, Delitti WBC. 1979. Ciclagem de nutrientes minerais na mata mesófila secundária - São Paulo. I. Produção e conteúdo de nutrientes minerais no folhedo. Boletim de Botânica da Universidade de São Paulo 7: 11-31.
• Metzger JP. 2010. O código florestal tem base científica? Natureza & Conservação 8: 92-99.
• Moraes RM, Delitti WBC, Struffaldi-de-Vuono Y. 1999. Litterfall and litter nutrient content in two Brazilian tropical forests. Revista Brasileira de Botânica 22: 9-16.
• Moreira-Turcq P, Seyler P, Guyot JL, Etcheber H. 2003. Exportation of organic carbon from the Amazon River and its main tributaries. Hydrological Processes 17: 1329-1344.
• Morellato LPC. 1992. Nutrient cycling in two south-east Brazilian forest. I Litterfall and litter standing crop. Journal of Tropical Ecology 8: 205-215.
• Moretti MS, Loyola RD, Becker B, Callisto M. 2009. Leaf abundance and phenolic concentrations codetermine the selection of case-building materials by Phylloicus sp. (Trichoptera, Calamoceratidae) . Hydrobiologia 630: 199-206.
• Moss B. 2010. Ecology of freshwaters: a view for the twenty-first century. Chichester, John Wiley and Sons.
• Naiman RJ, Decamps H. 1997. The ecology of interfaces: Riparian zones. Annual Review of Ecology and Systematics 28: 621-658.
• Naiman RJ, Elliot SR, Helfield JM, O'Keefe TC. 2000. Biophysical interactions and the structure and dynamics of riverine ecosystems: the importance of biotic feedbacks. Hydrobiologia 410: 79-86.
• Neill C, Deegan LA, Thomas SM, Cerri CC. 2001. Deforestation for pasture alters nitrogen and phosphorus in small Amazonian streams. Ecological Applications 11: 1817-1828.
• Oliveira-Filho AT, Ratter JA. 2002. Vegetation Physiognomies and Woody Flora of the Cerrado Biome. In: Oliveira PS, Marquis RJ. (Eds.). The Cerrados of Brazil: Ecology and Natural History of a Neotropical Savanna. New York. Columbia University Press. p. 91-201.
• Olson JS. 1963. Energy storage and the balance of producers and decomposers in ecological systems. Ecology 44: 322-331.
• Pagano SN. 1989a. Nutrientes minerais da serapilheira produzida em mata mesófila semidecídua no município de Rio Claro, SP. Revista Brasileira de Biologia 49: 641-647.
• Pagano SN. 1989b. Produção de serapilheira em mata mesófila semidecídua no município de Rio Claro, SP. Revista Brasileira de Biologia 49: 633-639.
• Palmer MA, Febria CM. 2012. The heartbeat of ecosystems. Science 336: 1393-1394.
• Phlips EJ, Cichra M, Aldridge FJ, Jembeck J, Hendrickson J, Brody R. 2000. Light availability and variations in phytoplankton standing crops in a nutrient-rich blackwater river. Limnology and Oceanography 45: 916-929.
• Pianka ER. 2000. Evolutionary ecology. San Francisco, Addison-Wesley Longman.
• Pinay G, Décamps H, Chauvet E, Fustec E. 1990. Functions of ecotones in fluvial systems. In: Naiman R, Décamps H. (eds.) Ecology and management of aquatic terrestrial ecotones. Paris, Unesco. p. 141-168.
• Ramírez A, Pringle CM, Wantzen KM. 2008. Tropical stream conservation. In: Dudgeon D. (ed.) Tropical stream ecology. London, Academic Press. p. 107-146.
• Richey JE, Hedges JI, Devol AH, et al. 1990. Biogeochemistry of carbon in the Amazon river. Limnology and Oceanography 359: 352-371.
• Rincón J, Martínez I. 2006. Food quality and feeding preferences of Phylloicus sp. (Trichoptera: Calamoceratidae) . Journal of the North American Benthological Society 25: 209-215.
• Schönborn W. 2003. Defensive reactions of freshwater ecosystems against external influence. Limnologica 33: 163-189.
• Schumacher MV, Brun EJ, Rodrigues LM, Santos EM. 2003. Retorno de nutrientes via deposição de serapilheira em um povoamento de acácia-negra (Acacia mearnsii De Wild.) no estado do Rio Grande do Sul. Revista Árvore 27: 791-798.
• Schumacher MV, Viera M, Witschoreck R. 2008. Produção de serapilheira e transferência de nutrientes em área de segunda rotação com floresta de Pinus taeda L. no município de Cambará do Sul, RS. Ciência Florestal 18: 471-480.
• Scott DA, Proctor J, Thompson J. 1992. Ecological studies on a lowland evergreen rain forest on Maraca Island, Roraima, Brazil. II. Litter and nutrient cycling. Journal of Ecology 80: 705-717.
• SMA - Secretaria do Meio Ambiente. 2005. Inventário florestal da vegetação natural do estado de São Paulo. São Paulo, Secretaria do Meio Ambiente, Instituto Florestal.
• Sombroek W. 2000. Amazon landforms and soils in relation to biological diversity. Acta Amazonica 30: 81-100.
• Sternberg HO. 1987. Aggravation of floods in the Amazon river as a consequence of deforestation? Geografiska Annaler Series A, Physical Geography 69: 201-219.
• Sweeney BW, Bott TL, Jackson JK, et al. 2004. Riparian deforestation, stream narrowing, and loss of stream ecosystem services. Proceedings of the National Academy of Sciences 101: 14132-14137.
• Tilman D, Cassman KG, Matson PA, Naylor R, Polasky S. 2002. Agricultural sustainability and intensive production practices. Nature 418: 671-677.
• Tockner K, Malard F, Ward JV. 2000. An extension of the flood pulse concept. Hydrological Processes 14: 2861-2883.
• Tundisi JG, Tundisi TM. 2010. Impactos potenciais das alterações do código florestal nos recursos hídricos. Biota Neotropica 10: 67-75.
• Turner MG, Gardner RH, O'Neill RV. 2001. Landscape ecology: in theory and practice. New York, Springer.
• United Nations Environment Programme. 2012. Global environment outlook (GEO 5): environment for the future we want. Malta, United Nations Environment Programme.
• Vaithiyanathan P, Correll DL. 1992. The rhodes river watershed: phosphorus distribution and export in forest and agricultural soils. Journal of Environmental Quality 21: 280-288.
• Valenti MW, Cianciaruso MV, Batalha MA. 2008. Seasonality of litterfall and leaf decomposition in a cerrado site. Brazilian Journal of Biology 68: 459-465.
• Vannote RL, Minshall GW, Cummins KW, Sedell JR, Gushing CE. 1980. The river continuum concept. Canadian Journal of Fisheries and Aquatic Sciences 37: 130-137.
• Vasconcelos HL, Luizão FJ. 2004. Litter production and litter nutrient concentrations in a fragmented Amazonian landscape. Ecological Applications 14: 884-892.
• Viera M, Schumacher MV. 2010. Teores e aporte de nutrientes na serapilheira de Pinus taeda L., e sua relação com a temperatura do ar e pluviosidade. Revista Árvore 34: 85-94.
• Vitousek PM, Howarth RW. 199l. Nitrogen limitation on land and in the sea: How can it occur? Biogeochemistry 13: 87-115.
• Wantzen KM, Wagner R. 2006. Detritus processing by invertebrate shredders: a neotropical-temperate comparison. Journal of the North American Benthological Society 25: 216-232.
• Wantzen KM, Yule CM, Tockner K, Junk WJ. 2008. Riparian wetlands of tropical streams. In: Dudgeon D. (ed.) Tropical stream ecology. London, Academic Press. p. 199-217.
• Winemiller KO, Agostinho AA, Caramaschi EP. 2008. Fish ecology in tropical streams. In: Dudgeon D. (ed.) Tropical stream ecology. London, Academic Press. p. 107-146.
• Wood CT, Schlindwein CCD, Soares GLG, Araujo PB. 2012. Feeding rates of Balloniscus sellowii (Crustacea, Isopoda, Oniscidea): the effect of leaf litter decomposition and its relation to the phenolic and flavonoid content. ZooKeys 176: 231-245.
• Woodward G, Gessner MO, Giller PS, et al. 2012. Continental-scale effects of nutrient pollution on stream ecosystem functioning. Science 336: 1438-1440.

Publication Dates

• Publication in this collection
  June 2015

History

• Received
  25 Nov 2014
• Accepted
  05 Mar 2015