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Sincronia e Índice de Divergência de Diversidade de Espécies
UNIVERSIDADE FEDERAL DE SÃO CARLOS
CENTRO DE CIÊNCIAS BIOLÓGICAS E DA SAÚDE
Programa de Pós-Graduação em Ecologia e Recursos Naturais
Sincronia e Índice de Divergência de Diversidade de
Espécies Anemocóricas.
KLÉCIA GILI MASSI
São Carlos – SP
2006
UNIVERSIDADE FEDERAL DE SÃO CARLOS
CENTRO DE CIÊNCIAS BIOLÓGICAS E DA SAÚDE
Programa de Pós-Graduação em Ecologia e Recursos Naturais
Sincronia e Índice de Divergência de Diversidade de
Espécies Anemocóricas.
KLÉCIA GILI MASSI
Orientador: Dr. Marco Antônio Batalha
Dissertação apresentada ao Programa de Pós
Graduação em Ecologia e Recursos Naturais
da Universidade Federal de São Carlos, como
parte dos requisitos para a obtenção do titulo
de Mestre em Ecologia.
São Carlos – SP
2006
Ficha catalográfica elaborada pelo DePT da
Biblioteca Comunitária da UFSCar
M417fd
Massi, Klécia Gili.
Sincronia e índice de divergência de diversidade de
espécies anemocóricas / Klécia Gili Massi. -- São Carlos :
UFSCar, 2006.
74 p.
Dissertação (Mestrado) -- Universidade Federal de São
Carlos, 2006.
1. Cerrados. 2. Cerrados - fisionomia. 3. Dispersão. 4.
Fenologia. 5. Anemocoria. I. Título.
CDD: 581.5264 (20a)
Aos meus pais, dedico.
Agradecimentos
•
Aos meus pais pelo apoio;
•
À Fê, Lú, Maria Helena e Rafa por todas as vezes que me acolheram e tão bem;
•
À Jane M. Polo pelo empréstimo de suas parcelas e por sua amizade;
•
À Vó Marta, por sua deliciosa companhia em Rio Claro;
•
Ao Prof. Waldir Mantovani, pela amizade e ajuda;
•
Ao Prof. Marco Antônio Batalha, pela orientação;
•
Aos companheiros de coleta: André, Gustavo e Thaísa;
•
Àqueles que nos ajudaram: Marcus, Igor, Fernanda, Sylene, Maira, Paola, Tadeu;
•
Ao Conselho Técnico do Instituto Florestal, pela autorização para a realização do projeto
(processo SMA 41.594/05);
•
Aos funcionários da Estação Ecológica e Experimental de Itirapina, em especial, à Dona
Isabel;
•
À todos os amigos e colegas do IB e da UFSCar;
•
Ao Programa de Pós Graduação em Ecologia e Recursos Naturais da Universidade
Federal de São Carlos.
Sumário
I.
Introdução geral ................................................................................................................... 9
Referências Bibliográficas .................................................................................................... 14
II. Capítulo 1........................................................................................................................... 16
ABSTRACT .......................................................................................................................... 19
RESUMO .............................................................................................................................. 19
Introduction ........................................................................................................................... 21
Material and Methods ........................................................................................................... 22
Results ................................................................................................................................... 24
Discussion ............................................................................................................................. 25
Acknowledgments................................................................................................................. 28
References ............................................................................................................................. 28
III. Capítulo 2 ....................................................................................................................... 42
ABSTRACT. ......................................................................................................................... 45
RESUMO. ............................................................................................................................. 46
METHODS ........................................................................................................................... 49
RESULTS ............................................................................................................................. 52
DISCUSSION ....................................................................................................................... 53
ACKNOWLEDGEMENTS .................................................................................................. 58
LITERATURE CITED ......................................................................................................... 58
IV. Conclusão Geral ............................................................................................................. 72
Resumo
O Domínio do Cerrado é a segunda maior região fitogeográfica brasileira, originalmente
cobrindo 23% do território brasileiro, sob influência de clima estacional. O cerrado apresenta
variação florística e fisionômica, indo desde uma fisionomia campestre até uma florestal.
Espécies anemocóricas são proporcionalmente mais importantes no cerrado do que em
florestas tropicais, especialmente em fisionomias mais abertas. As características
morfológicas dos diásporos anemocóricos parecem diminuir suas razões de descida,
aumentando a chance de exposição aos ventos e de encontrar locais seguros para germinar.
Espécies anemocóricas tendem a frutificar na melhor época para dispersar suas sementes.
Também a altura de liberação e a vegetação circundante são fundamentais para a dispersão à
longas distâncias. Selecionamos as espécies anemocóricas de três levantamentos
fitossociológicos, um realizado em área nuclear, dois em área disjunta, e as classificamos em
autogiro, autogiro-rotativas, flutuantes e planadoras, de acordo com a morfologia e
comportamento do diásporo no ar parado. Tínhamos o período de frutificação para cada
espécie anemocórica de uma área disjunta e tentamos observar a existência de estacionalidade
na frutificação e a relação desta com algumas variáveis climáticas. O número de espécies
frutificando foi maior na estação seca, coincidindo com o período de menores pluviosidade e
umidade relativa do ar. Depois, estudamos os espectros de diásporos anemocóricos e os
índices de divergência de diversidade (IDD) de espécies a tipos de diásporo anemocórico de
três fisionomias do cerrado (campo cerrado, cerrado sensu stricto e cerradão) em uma área
disjunta; e de três fisionomia de cerrado (cerrado sensu stricto) em províncias florísticas
diferentes. Além de haver uma unidade florística na área disjunta, com a fisionomia ecotonal
contendo elementos campestres e florestais, as áreas nuclear e disjuntas foram ecologicamente
semelhantes quanto à distribuição de espécies anemocóricas. No entanto, o tamanho das
populações diferiu entre as três fisionomias e entre as três áreas, e levou a diferenças
significativas quando as abundâncias das espécies foram consideradas. Em locais mais
densos, a vegetação reduz a velocidade do vento no estrato inferior, restringindo a dispersão
das espécies herbáceas, enquanto espécies anemocóricas de sementes mais pesadas, requerem
o lançamento a partir de árvores ou lianas.
Palavras-chave: anemocoria, cerrado, dispersão pelo vento, divergência de diversidade
intrínseca, fenologia, fisionomias, savana.
Abstract
The Cerrado Domain is the second largest Brazilian phytogeographic province, occupying
originally 23% of Brazil’s land surface, under seasonal climate. The cerrado presents a
floristic and physiognomic variation, ranging from grassland to tall woodland. Anemochorous
species are proportionally more important in the cerrado than in Brazilian rain forests,
especially in open physiognomies. Morphological designs of wind-dispersed diaspores appear
to slow their rates of descent, increasing their chances of exposure to winds and of reaching
safe sites to germinate. Wind-dispersed species are constrained to fruit during the best time
for seed dispersal. Also, the height of seed release and surrounding vegetation are
fundamental to long-distance dispersal. We selected the wind-dispersed species from three
phytosociological surveys (disjoint and core sites) and classified them into autogyro, rollingautogyro, floater, or undulator, according to the diaspore morphology and aerodynamic
behavior in still air. For each species, we had data on its fruiting period. We tried to assess
whether there was a seasonality and, if there was, whether it was synchronized with some
climatic conditions. The number of fruiting anemochorous cerrado species was highest at the
dry season, coinciding with reduced precipitation. Next, we studied the anemochorous
diaspore spectra and index of divergence from species to anemochorous diaspore diversity
(IDD) in three cerrado physiognomies (campo cerrado, cerrado sensu stricto, and cerradão)
in a disjoint site and three cerrado physiognomies (cerrado sensu stricto) in different floristic
pronvinces. There was a floristic unit among the cerrado physiognomies, with the ecotonal
ones containing both grassland and woodland elements. Both nuclear and disjoint sites were
ecologically similar regarding the species distribution. However, there were differences when
species abundances were considered. In denser sites, vegetation reduces wind velocity in
lower strata, constraining dispersal of herbaceous species and heavy-seeded, wind-dispersed
species require launching from a tree or high climber.
Key-words: anemochory, cerrado, intrinsic diversity divergence, phenology, physiognomies,
savanna, wind dispersal.
I. Introdução geral
10
Introdução Geral
A dispersão de sementes geralmente está relacionada a melhores condições para sua
liberação e para o estabelecimento das plântulas e talvez por isso a maioria das espécies
anemo ou autocóricas, com frutos secos e deiscentes, frutifique durante a estação seca
(Morellato & Leitao-Filho 1996). A dispersão é um processo ecológico multifásico (Fuentes
2000) que não só determina a área potencial do recrutamento das novas gerações de plantas
como também exerce influência em processos subseqüentes, tais como predação, competição
e reprodução (Nathan & Muller-Landau 2000).
A dispersão é considerada como a partida de um diásporo (fruto ou semente) da planta
matriz (Howe & Smallwood 1982), variando espácio-temporalmente (Solbrig 1980). No
espaço, envolve o transporte dos diásporos por agentes físicos, como o vento ou a água, ou
por agentes biológicos, os animais; no tempo, refere-se ao fato de que a semente pode assumir
uma condição de dormência ou germinar, assim que for enterrada (Solbrig 1980). As
características dos propágulos constituem síndromes de dispersão (Pijl 1969), que podem ser
classificadas de acordo com o agente dispersor: saurocoria (dispersão por répteis), ornitocoria
(aves), mamalocoria (mamíferos), mirmecocoria (formigas), anemocoria (vento), hidrocoria
(água) e autocoria (mecanismos explosivos ou gravidade). A anemocoria conta com estruturas
plumadas, aladas e pulverulentas (Harper 1977).
Na vegetação tropical, a anemocoria é, de forma geral, menos freqüente que os vetores
bióticos (Pijl 1969). Nesta região, a dispersão pelo vento está associada aos ambientes mais
secos (Frankie et al. 1974) e às áreas mais abertas (Howe & Smallwood 1982). Em florestas
tropicais, no mínimo 50% e freqüentemente 75% ou mais das espécies arbóreas possuem
frutos carnosos adaptados ao consumo e à dispersão por aves e por mamíferos, enquanto que,
11
nas savanas, essa proporção diminui, aumentando a anemocoria conseqüentemente (Howe &
Smallwood 1982). Assim, em florestas tropicais, os principais vetores de sementes são os
vertebrados frugívoros (Janzen 1967), sendo as espécies anemocóricas proporcionalmente
mais importantes em hábitats mais secos, como o cerrado (Oliveira & Moreira 1992) e as
matas secas (McKey 1975).
O cerrado apresenta grande variação fisionômica, indo de uma fisionomia campestre
(campo limpo) a uma florestal (cerradão), passando por fisionomias savânicas (campo sujo,
campo cerrado e cerrado sensu stricto) (Coutinho 1978). No cerrado, há dois componentes, o
arbustivo-arbóreo e o herbáceo-subarbustivo (Rizzini 1979), cujas importâncias variam de
modo inverso. Enquanto que a importância do componente arbustivo-arbóreo aumenta do
campo limpo ao cerradão, a do componente herbáceo-subarbustivo diminui (Coutinho 1978).
A maioria dos estudos realizados em comunidades de cerrado não subdividiram a síndrome
anemocórica (Mantovani & Martins 1988, Miranda 1995, Batalha et al. 1997, Batalha &
Mantovani 2000, Bulhão & Figueiredo 2002, Vieira et al. 2002, Batalha & Martins 2004). O
entendimento das relações específicas planta-agente dispersor (o vento na anemocoria) são
fundamentais para se manter a dinâmica, a estrutura e a diversidade das comunidades
tropicais (Figliolia & Kageyama, 1995).
Apresentamos a dissertação em capítulos, formatando-os de acordo com as normas das
revistas científicas a que foram submetidos. O capítulo 1 foi formatado segundo as normas da
revista ‘Revista Brasileira de Botânica’. O capítulo 2 foi formatado segundo as normas da
revista ‘Biotropica’. Os capítulos foram redigidos na língua inglesa. O primeiro artigo já foi
submetido à revista e estamos aguardando o parecer dos assessores. Como os capítulos são
independentes, repetições tornaram-se inevitáveis.
No primeiro capítulo, procuramos observar a existência de estacionalidade na frutificação
das espécies anemocóricas de uma área de cerrado localizada na Reserva Pé-de-Gigante
12
(Figura 1), Santa Rita do Passa Quatro, SP. Já no segundo capítulo procuramos comparar, a
partir de um índice de divergência diferentes fisionomias de cerrado (campo cerrado, cerrado
sensu stricto e cerradão) dentro da Reserva Pé-de-Gigante, e três áreas de cerrado sensu
stricto situadas em províncias fitogeográficas distintas (Ratter et al. 2003), uma na região
central (Figura 2) e duas na região sudeste do Brasil: Santa Rita do Passa Quatro, SP e
Itirapina, SP (Figura 3).
Figura 1. Foto aérea da Gleba Cerrado Pé-de-Gigante, Santa Rita do Passa Quatro, SP (21º36-44’S, 47º3441’W).
13
Figura 2. Localização das áreas amostradas, abrangendo os estados de GO, MT e MS.
Figura 3. Imagem de satélite da Estação Ecológica e Experimental de Itirapina (22°13´S e 47°51´W), São Paulo
(Fonte: Embrapa).
14
Referências Bibliográficas
BATALHA, M. A; ARAGAKI, S. & MANTOVANI, W. 1997. Variações fenológicas das espécies
do cerrado em Emas (Pirassununga, SP). Acta Botanica Brasílica 11: 61-78.
BATALHA, M. A. & MANTOVANI, W. 2000. Reproductive phenological patterns of cerrado
plant species at the Pé-de-Gigante Reserve (Santa Rita do Passa Quatro, SP, Brazil): a
comparison between the herbaceous and woody floras. Revista Brasileira de Biologia 60:
129-145.
BATALHA, M. A. & MARTINS, F. R. 2004. Floristic, frequency, and vegetation life-form
spectra of a cerrado site. Revista Brasileira de Biologia 64(2): 203-209.
BULHÃO, C. F. & FIGUEIREDO, P. S. 2002. Fenologia de leguminosas arbóreas em uma área de
cerrado marginal no nordeste do Maranhão. Revista Brasileira de Botânica 25(3): 361-369.
COUTINHO, L. 1978. O conceito do cerrado. Revista Brasileira de Botânica 1: 17-23.
FIGLIOLA, M. B. & KAGEYAMA, P. Y. 1995. Dispersão de sementes de Inga uruguensis Hook.
et Arn. em floresta ripária do Rio Moji Guaçu, município de Moji Guaçu, SP. Revista do
Instituto Florestal 7: 65-80.
FRANKIE, G. W.; BAKER, H. G. & OPLER, P. A. 1974. Comparative phonological studies of
trees in tropical wet and dry forest in the lowlands Costa Rica. Journal of Ecology 62: 881919.
FUENTES, M. 2000. Frugivory, seed dispersal and plant community ecology. Trends in
Ecology and Evolution 15: 487-488.
HARPER, J. L. 1977. The Population Biology of Plants. Academic, New York.
HOWE, H. F. & SMALLWOOD, J. 1982. Ecology of seed dispersal. Annual Review of Ecology
and Systematics 13: 201-228.
JANZEN, D. H. 1967. Sinchronization of sexual reproduction of trees within the dry season in
15
Central America. Evolution 21: 620-627.
MANTOVANI, W. & MARTINS, F. R. 1988. Variações fenológicas das espécies do cerrado da
Reserva Biológica de Moji Guagu, Estado de São Paulo. Revista Brasileira de Botânica 11:
101-112.
MCKEY, D. 1975. The ecology of coevolved seed dispersal systems. In: GILBERT, L. E. &
RAVEN, P. H. (eds). Coevolution in animals and plants, pp159-191. University of Texas
Press, Austin.
MIRANDA, I. S. 1995. Fenologia do estrato arbóreo de uma comunidade de cerrado em Alterdo-Chão, PA. Revista Brasileira de Botânica 18: 235-240.
MORELLATO, L. P. C. & LEITÃO-FILHO, H. DE F. 1996. Reproductive phenology of climbers in
a southeastern brazilian Forest. Biotropica 28: 180-191.
NATHAN, R. & MULLER-LANDAU, H. C. 2000. Spatial patterns of seed dispersal, their
determinants and consequences for recruitment. Trends in Ecology and Evolution 15: 278285.
OLIVEIRA, P. E. & MOREIRA, A. G. 1992. Anemocoria em espécies de cerrado e mata de
galeria de Brasília, DF. Revista Brasileira de Botânica 15: 163-174.
PIJL, L. VAN DER. 1969. Principles of dispersal in higher plants. Springer-Verlarg, Berlin.
RIZZINI, C. T. 1997. Tratado de fitogeografia do Brasil: Aspectos ecológicos, sociológicos e
florísticos. Âmbito Cultural, Rio de Janeiro.
SOLBRIG, O. T. 1980. Demography and evolution in plant population. Blackwell Scientific,
Oxford.
VIEIRA, D. L. M.; AQUINO, F. G.; BRETO, M. A.; BULHÃO, C. F. & HENRIQUES, R. P. B. 2002.
Síndromes de dispersão de espécies arbustivo-arbóreas em cerrado sensu stricto do Brasil
Central e savanas mazônicas. Revista Brasileira de Botânica 25(2): 215-220.
16
II. Capítulo 1
17
Sincronia na frutificação de espécies anemocóricas em
uma área de cerrado (Santa Rita do Passa Quatro, São
Paulo)1
1
Trabalho submetido ao periódico Revista Brasileira de Botânica com o título “Fruiting
Synchrony of Anemochorous Species in a Disjoint Cerrado Site (Santa Rita do Passa Quatro,
Southeastern Brazil)”.
18
Fruiting Synchrony of Anemochorous Species in a Disjoint Cerrado Site (Santa Rita do
Passa Quatro, Southeastern Brazil)
KLÉCIA GILI MASSI1,2, MARCO ANTÔNIO BATALHA2 AND WALDIR MANTOVANI3
Running title: Fruiting synchrony of anemochorous species
1
Corresponding author: [email protected]
Universidade Federal de São Carlos. Departamento de Botânica, Caixa Postal 676, 13.565-905, São Carlos, SP,
Brasil.
3
Universidade de São Paulo. Departamento de Ecologia, Caixa Postal 11461, 05422-970, São Paulo, SP, Brasil.
2
19
ABSTRACT – (Fruiting synchrony of anemochorous species in a disjoint cerrado site (Santa
Rita do Passa Quatro, southeastern Brazil)). Plant species share reproductive characteristics
that facilitate the process of dispersal by some vectors, which may be called ‘syndromes’,
including dispersal by wind, or anemochory. In anemochory, there are dust, plumed, and
winged dispersal units. From data collected in a disjoint cerrado reserve, we selected
anemochorous species and classified them as autogyro, rolling-autogyro, floater or undulator
species. For each species, we had data on its fruiting period. We tried to assess whether there
was a fruiting peak and, if there was, whether it was synchronized with some climatic
conditions. The number of fruiting anemochorous species was not uniformly distributed
throughout the year and peaked in dry season, negatively related with air relative humidity
and rainfall. The number of fruiting anemochorous cerrado species was highest at the dry
season, coinciding with deciduousness of trees and shrubs, diminished air humidity during the
day, reduced precipitation, and a higher permanent wind intensity. At the dry season, winddispersed fruits dehydrate and many species shed leaves, favoring diaspores dispersal. Floater
and autogyro species were more frequent in the herbaceous component; and undulator species
were more frequent in the woody component. Plumed and winged diaspores should prevail in
open and closed physiognomies, respectively.
Key words – anemochory, cerrado, phenology, savanna, synchronization.
RESUMO – (Sincronia de frutificação de espécies anemocóricas em uma área disjunta de
cerrado (Santa Rita do Passa Quatro, SP)). Espécies vegetais compartilham características
reprodutivas que facilitam o processo de dispersão por alguns vetores, que podem ser
chamadas de síndromes, incluindo a dispersão pelo vento, ou anemocoria. Na anemocoria, há
unidades de dispersão aladas, plumadas e pulverulentas. A partir de dados coletados em uma
20
área disjunta de cerrado, selecionamos as espécies anemocóricas e as classificamos em
autogiro, autogiro-rotativas, flutuantes e planadoras. Para cada espécie, tínhamos dados sobre
seu período de frutificação. Procuramos testar se havia um pico na frutificação e, se houvesse,
se ele era sincrônico com algumas condições climáticas. A frutificação das espécies
anemocóricas não foi distribuída uniformemente ao longo do ano, tendo seu pico durante a
estação seca e relacionando-se negativamente com a umidade relativa do ar e precipitação. O
número de espécies anemocóricas com frutos foi maior na estação seca, coincidindo com a
deciduidade de árvores e arbustos, menor umidade relativa do ar durante o dia, precipitação
reduzida e ventos mais intensos. Na estação seca, frutos dispersos pelo vento desidratam e
muitas espécies trocam suas folhas, favorecendo a dispersão dos diásporos. Espécies de
diásporos autogiro e flutuantes foram mais freqüentes no componente herbáceo-subarbustivo.
Espécies de diásporos planadores foram mais freqüentes no componente arbustivo-arbóreo.
Diásporos plumados e alados devem prevalecer em fisionomias abertas e fechadas,
respectivamente.
Palavras-chave: anemocoria, cerrado, fenologia, savana, sincronia.
21
Introduction
Plant species share reproductive characteristics that facilitate the process of dispersal by
some vectors, which may be called ‘syndromes’ (Dalling 2002), including dispersal by wind,
or anemochory (Pijl 1969). Morphological designs of wind-dispersed diaspores appear to
slow their rates of descent, increasing their chances of exposure to winds and of reaching safe
sites (Ausgpurger 1986). In anemochory, there are dust, plumed, and winged dispersal units
(Harper 1977). Dust seeds, usually so small that movement in air is dominated by viscous
forces, and plumed diaspores, which depend on strucuture such as the plumes on the seed or
fruit coat, float downward in a vertical line (Harper 1977). Winged diaspores may have the
seed mass concentrated in a central area (Pijl 1969) and glide and undulate (Augspurger
1986). When the seed mass is not concentrated in a central area, the seed may rotate around
its end (autogyro), rotate on two axes simultaneously (rolling-autogyro), or spin tightly
around a vertical line (helicopter) (Augspurger 1986).
The Cerrado Domain is the second largest Brazilian phytogeographic province, occupying
originally 23% of Brazil’s land surface, especially in the Central Plateau, under seasonal
climate, with wet summer and dry winter (Ratter et al. 1997). The cerrado flora has two
components, a woody one and an herbaceous one, which are distinct and antagonistic
(Coutinho 1990). The cerrado species present periodic variations in flower and fruit
production that may represent adaptations to biotic and abiotic factors, like those of other
savannas (Schaik et al. 1993). Anemochorous species are proportionally more important in
the cerrado than in Brazilian rain forests, especially in open physiognomies (Oliveira &
Moreira 1992).
Climatic conditions determine the time of fruit ripening, and wind-dispersed species are
constrained to fruit during the best time for seed dispersal (Morellato & Leitão-Filho 1996;
22
Marques et al. 2004). This synchronization is a very effective means of increasing wind
dispersal potential (Tackenberg et al. 2003). If the climate of the cerrado is seasonal and
anemochorous cerrado species fruit mainly in the dry season (Mantovani & Martins 1988,
Oliveira & Moreira 1992, Miranda 1995, Batalha et al. 1997, Batalha & Mantovani 2000,
Batalha & Martins 2004), then they would have the whole rainy season to develop their roots
before the next dry season (Morellato et al. 1989).
Regarding anemochorous species, even if, by definition, all diaspores are dispersed by
wind, fruiting peak and synchronization with climatic variables of each subtype may be
different. For instance, in a core cerrado area, on the one hand, different species with floater
and helicopter diaspores presented similar patterns, with short fruiting periods at the dry
season; on the other hand, species with undulator seeds presented longer fruiting periods, and
the autogyro and rolling-autogyro species presented distinct fruiting periods for each species
(Oliveira & Moreira 1992).
Batalha & Mantovani (2000) analyzed the fruiting patterns of anemochorous species in a
disjoint cerrado site, in southeastern Brazil, but did not tested for differences among the types.
So, given the existence of different types of wind-dispersed diaspores (autogyro, rollingautogyro, floater, helicopter, and undulator) and the possibility of different fruiting patterns
among them, we aimed to answer the following questions: when is the fruiting peak of
anemochorous species in a disjoint cerrado site? Is this peaking period synchronized with
some climatic conditions? Do the different types of wind-dispersed diaspores present similar
fruiting patterns?
Material and Methods
This study was carried out in the Pé-de-Gigante (Giant’s foot) Reserve, Santa Rita do
23
Passa Quatro, São Paulo State, southeastern Brazil, 21°36-39’S and 47°36-38’W, under
Köppen’s Cwag’ climate, at 660 to 730 m high a.s.l., on Red-Yellow Latosol, with 1,269 ha,
covered mainly by cerrado (Pivello et al. 1998, in which a more detailed characterization of
the study area can be found). The climatic diagram (Fig. 1) shows that the dry period of the
year lies from June to August, and the wet one from September to May (Batalha & Mantovani
2000). Mean annual rainfall and mean monthly temperature are, respectively, 1499 mm and
21.5oC.
Batalha & Mantovani (2000) collected the vegetation data used here, from September 1995
to February 1997, when they observed, among other things, whether each species was fruiting
in a given month. We filtered their matrix and selected cerrado anemochorous species,
classifying each one of them according to aerodynamic group into autogyro, rolling-autogyro,
floater, helicopter, or undulator (Augspurger 1986). We consulted taxonomic descriptions of
the species and observed the fruits in lodged vouchers at the University of São Paulo
herbarium. We classified the species as belonging to either the woody component
(phanerophytes, sensu Raunkiaer 1934) and or the herbaceous component (nonphanerophytes, sensu Raunkiaer 1934).
We applied circular statistics to our data and used Rayleigh test (Zar 1999) to check
whether the anemochorous species fruited uniformly throughout the year. January
corresponded to 0°; February, to 30°; March, to 60°; and so on. First, we applied Rayleigh test
to all anemochorous species together and, then, to each aerodynamic group separately. To
check whether the numbers of autogyro, rolling-autogyro, floater, helicopter, and undulator
species were significantly different to an even distribution in each component, we applied the
chi-square test (Zar 1999). To test the relationships of fruiting and climatic variables (mean
air temperature, air relative humidity, and rainfall), we used simple linear regresions (Zar
1999).
24
Results
Of the 123 anemochorous species, we considered 36 as belonging to the woody component
and 87 as belonging to the herbaceous component (Table 1). We did not find 37 out of the 123
species (30%) producing fruits. The number of fruiting anemochorous species was not
uniformly distributed throughout the year (z = 5.54, 0.005 > P > 0.002, Fig. 2). The mean
angle for the fruiting anemochorous species was 230°, which corresponded to the end to
August. The number of fruiting anemochorous species was negatively related with air relative
humidity (R² = 0.67, F = 19.96, P = 0.002, Table 2) and with rainfall (R² = 0.58, F = 13.75, P
= 0.004, Table 2), but not with temperature (R² = 0.32, F = 4.79, P = 0.052, Table 2).
Regarding the aerodynamic groups, 60 species were floater ones (48.8%); 26, rollingautogyro (21.1%); 26, autogyro (21.1%); and 11, undulator (9.0%). None of them was
helicopter-diaspore species. Considering the four aerodynamic groups found, these
proportions were significantly different to an even distribution (χ² = 41.98, P < 0.001). The
distribution of aerodynamical groups was significantly different to an even distribution in the
herbaceous component (χ² = 67.34, P < 0.001), but not in the woody one (χ² = 3.33, P = 0.34).
On the one hand, the proportion of rolling-autogyro species was similar in both components;
on the other hand, the proportions of autogyro and floater-diaspore species were higher in the
herbaceous component and of undulator-diaspore species was higher in the woody component
(Table 3).
The numbers of fruiting species with autogyro, rolling-autogyro, and undulator diaspores
were uniformly distributed throughout the year (Fig. 3a, b and d, respectively). The only
group with seasonal fruiting was those of the floater-diaspore species (z = 6.13, 0.005 > P >
0.002, Fig. 3c), with mean angle at 258°, which corresponded to the end to September. The
25
number of fruiting floater-diaspore species was negatively related with temperature (R² =
0.55, F = 12.04, P = 0.006, Table 2), with rainfall (R² = 0.80, F = 39.69, P < 0.001, Table 2)
and with air relative humidity (R² = 0.53, F = 11.07, P = 0.008, Table 2).
Discussion
Fruiting of anemochorous species in the community we studied was not uniformly
distributed throughout the year, reflecting the seasonality of the cerrado climate (Monasterio
& Sarmiento 1976). In cerrado sites, wind-dispersed species tend to fruit mainly in the dry
season, when the dispersal of their diaspores is more efficient (Mantovani & Martins 1988,
Miranda 1995, Batalha et al. 1997, Batalha & Martins 2004). In other tropical vegetation
types, such as Brazilian dry forest (Griz & Machado 2001) and central American rain forest
(Smythe 1970), wind-dispersed seeds fall chiefly throughout the dry season and the time of
highest winds.
Despite this seasonality in fruiting of anemochorous species, a high proportion of them did
not fruit in the sampling period. Individuals of many tropical trees may skip fruiting in some
years, what may be compensated by efficient vegetative propagation (Gottsberger &
Silberbauer-Gottsberger 1983). On the contrary, some species fruited for long periods, more
than six months, as for example, Banisteriopsis campestris, Machaerium acutifolium, and
Qualea parviflora. Ripening time for some of these species may be extended, reflecting the
seasonal unpredictability or scarcity of resources needed for fruit development (Rathcke &
Lacey 1985). The time of fruit ripening should reflect timing of conditions that influence
dispersal success (Gottsberger &Silberbauer-Gottsberger 1983). Due to the exposure of
diaspore to different conditions, dry fruits remaining on the trees could be beneficial for seed
dispersal (Devineau 1999). For instance, longer release period for Pinus diaspores exposes
26
them to much greater variation in horizontal and vertical wind speeds (Greene & Johnson
1989).
The higher proportion of floater-diaspore species we found was different to other studies:
in central Brazilian riparian forests, most species were autogyro (Pinheiro & Ribeiro 2001)
and, in a core cerrado site, most species were autogyro and rolling-autogyro (Oliveira &
Moreira 1992). In a more closed cerrado physiognomy, anemochorous species presented a
higher proportion of winged (18%) than plumed (7%) dispersal units (Gottsberger &
Silberbauer-Gottsberger 1983), whereas the opposite was found for us. We found a higher
proportion of undulator dispersal units among woody species and of floater and autogyro
dispersal units among herbaceous species, suggesting different ecological strategies between
the two cerrado components. Indeed, woodiness is positively correlated with winged dispersal
units, whereas, among herbs, plumed dispersal units are more commom (Gottsberger &
Silberbauer-Gottsberger 1983). We may, then, postulate that plumed and winged diaspores
should prevail in open and closed physiognomies, respectively.
A seed is released at a height where there is sufficient wind speed to transport (Soons et al.
2004). Autogyro and rolling-autogyro species have structures that do not allow long-distance
flights and, even if wind is strong, height of release is more important; floater diaspores, on
the contrary, have high capacity of being transported, even in still air (Hensen & Muller
1997). Most helicopter-diaspore species are not tall, and the wind that blows in lower strata is
weaker (Soons et al. 2004). Seeds that are released from lower heights are generally dispersed
over shorter distances: first, they experience lower wind velocities; second, they fall over a
shorter distance and hence have a shorter flight time; and third, they experience less organized
wind turbulence and hence the probability of uplifting is lower (Soons et al. 2004). In short
cerrado species, dispersal by wind may be dependent on casual events, such as occasional
whirlwinds or burnings that clear the vegetation and allow dispersal over longer distances
27
(Coutinho 1978).
The only aerodyamic group with seasonal fruiting was the floater-diaspore species, maybe
due to phylogenetic constraints. The other groups presented longer fruting periods, well
distributed throughout the year. Floater and undulator species should concentrate their fruiting
periods at the dry season due to the hydrophobic bevahior of hyaline wings and plumes
(Hensen & Muller 1997).
There is a negative influence of humidity in anemochory, which requires auxiliary
mechanisms to expose seeds at the right time (Pijl 1969) and find the most favorable period to
ripening (Bawa & Hadley 1990). We found significant relationships between fruiting
anemochorous species and air relative humidity and rainfall. Anemochory seems to be
favoured by specific environmental conditions, such as greater wind circulation and less
rainfall (Griz & Machado 2001). The number of fruiting anemochorous cerrado species is
highest at early dry season, coinciding with deciduousness of trees and shrubs, diminished air
humidity during the day, reduced precipitation, and a higher permanent wind intensity
(Gottsberger & Silberbauer-Gottsberger 1983). At the dry season, wind-dispersed fruits
dehydrate and many species shed leaves, favoring diaspores dispersal (Mantovani & Martins
1988). Additional studies on wind dispersal among cerrado species may include source
density (Mc Euen & Curran 2004), height of seed release, terminal velocity, turbulence, wind
speed (Harper 1977), convective updrafts, surrounding vegetation, uplifting of seeds (Soons et
al. 2004), and the diaspore morphological structure (Hensen & Muller 1997).
28
Acknowledgments – We are grateful to the São Paulo State Forestry Institute, for granting the
research permit; to T.B. Almeida, S. del Carlo, G. Carvalho, M.V. Cianciaruso, A.V. FleuriJardim, P. Maia, M. Nunes, and I.A. Silva, for help in the field; and to J. M. Polo, for logistic
assistance.
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32
Table 1. Anemochorous species in the Pé-de-Gigante Reserve, Santa Rita do Passa Quatro, SP
(21º 36-39`S, 47º 36-38`W). H = herbaceous, W = woody; A = autogyro, RA = rolling
autogyro, F = floater, U = undulator.
Family/ species
Apocynaceae
Aspidosperma tomentosum Mart.
Forsteronia glabrescens M. Arg.
Himatanthus obovatus (M. Arg.) Woods.
Mandevilla vellutina (Mart.) Woods.
Odontadenia lutea (Vell.) Markgr.
Rhodocalyx rotundifolius M. Arg.
Temnadenia violacea (Vell.) Miers
Aristolochiaceae
Aristolochia gilberti Hook.
Asclepidaceae
Astephanus carassensis Malme
Blepharodon nitidum (Vell.) J. Macbr.
Ditassa acerosa Mart.
D. nitida E. Fourn
Oxypetalum appendiculatum Mart. & Zucc.
Asteraceae
Baccharis dracunculifolia A. DC.
B. humilis Sch. Bip.
B. rufescens Spreng.
Chaptalia integerrima (Vell.) Burk
Conyza canadensis (Less.) Cronquist
Dasyphyllum sprengelianum (Gardner) Cabrera
Elephantopus biflora Less.
E. mollis Less.
Emilia coccinea (Simns) Sw.
Eremanthus sphaerocephalus Baker
Eupatorium chlorolepsis Baker
E. maximiliani Sch.
E. squalidum A. DC.
Gochnatia barrosii Cabrera
G. pulchra Cabrera
Kanimia oblongifolia Baker
Mikania cordifolia (Less.) Willd.
Orthopappus angustifolius (Sw.) Gleason
Piptocarpha rotundifolia (Less.) Baker
Porophyllum angustissimum Gardner
P. ruderale (Jacq.) Cass.
Pterocaulon rugosum (Vahl) Malme
Trichogonia salviifolia Gardner
Vanillosmopsis erythropappa (A. DC.) Sch. Bip.
Vernonia apiculata Mart.
component
aerodynamic group
W
H
W
H
H
H
H
U
F
U
U
F
U
F
H
RA
H
H
H
H
H
F
F
U
U
F
H
H
H
H
H
H
H
H
H
W
H
H
H
H
H
H
H
H
W
H
H
H
H
W
H
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
33
(cont.)
V. bardanoides Less.
V. cephalotes A. DC.
V. ferruginea Less.
V. herbacea (Vell.) Rusby
V. holosericea Mart.
V. lappoides Baker
V. obtusata Less.
V. onopordioides Baker
V. polyanthes (Spr.) Less.
V. rubriramea Mart.
V. scabra Pers.
Bignoniaceae
Anemopaegma arvense (Vell.) Stellfeld
A. chamberlaynii (Simns) Bur. & K. Schum.
Arrabidaea brachypoda (A. DC.) Bur.
A. craterophora (A. DC.) Bur.
A. florida A. DC.
Cremastus pulcher (Cham.) Bur.
Cybistax antisyphillitica (Mart.) Mart.
Distictella mansoana (A. DC.) Urban
Jacaranda caroba (Vell.) A. DC.
J. decurrens Cham.
J. rufa Silva Manso
Memora peregrine (Miers.) Sandwith.
Pyrostegia venusta (Ker) Bur.
Tabebuia aurea (Silva Manso) S. Moore
T. ochracea (Cham.) Standl.
Zeyhera montana Mart.
Celastraceae
Austroplenckia populnea Reissek
Clusiaceae
Kielmeyera coriacea Mart.
K. rubriflora Cambess.
K. variabilis Mart.
Cochlospermaceae
Cochlospermum regium (Mart.) Pilg.
Fabaceae
Acosmium dasycarpum (Vog.) Yakovlev
A. subelegans (Mohl) Yakovlev
Bowdichia virgilioides H. B. K
Dyptichandra aurantiaca (Mart.) Tul.
Machaerium acutifolium Vogel
Mimosa gracilis Benth.
M. xanthocentra Mart.
Plathymenia reticulata Benth.
Platypodium elegans Vogel
Pterodon pubescens Benth.
Sclerolobium paniculatum Vogel
H
H
H
H
H
H
H
H
H
H
H
F
F
F
F
F
F
F
F
F
F
F
H
H
H
H
H
H
W
H
W
H
H
H
H
W
W
W
U
U
RA
RA
RA
RA
U
RA
RA
RA
RA
RA
RA
RA
RA
U
W
RA
W
W
W
RA
RA
RA
H
F
W
W
W
W
W
H
H
W
W
W
W
RA
RA
RA
U
A
RA
RA
U
A
RA
RA
34
(cont.)
Vatairea macrocarpa (Benth.)Ducke
Malpighiaceae
Banisteriopsis argyrophylla (A. Juss.) B. Gates
B. campestris (A. Juss.) Little
B. laevifolia (A. Juss.) B. Gates
B. pubipetala (A. Juss.) Cuatrec
B. stellaris (Griseb) B. Gates
B. variabilis B. Gates
Heteropteris byrsonimifolia A. Juss.
H. umbellata A. Juss.
Mascagnia cordifolia (A. Juss.) Griseb
Peixotoa tomentosa A. Juss.
Malvaceae
Eriotheca gracilipes (K.Schum.) A. Robyns
Pseudobombax longiflorum (Mart. & Zucc.)
Melastomataceae
Leandra lacunosa Cogn.
Tibouchina stenocarpa (A. DC.) Cogn
Orchidadeae
Galeandra montana Barb. Rodr.
Ionopsis paniculata Lindl.
Poaceae
Aristida jubata (Arechav.) Herter
Digitaria insularis (L.) Fedde
Gymnopogon foliosus (Willd.) Nees
Melinis minutiflora P. Beauv.
Rhynchelitrum repens (Nees) C. E. Hubb.
Schyzachirium condensatum (Kunth.) Nees
Polygalaceae
Securidaca tomentosa A. St-Hil.
Polypodiaceae
Adiantum fructuosum Spreng.
Polypodium latipes Langsd. & Fisch.
Proteaceae
Roupala montana Aubl.
Rhamnaceae
Crumenaria polygaloides Reissek
Sapindaceae
Magonia pubescens St.-Hil.
Paullinia elegans Cambess.
Serjania erecta Radlk.
S. lethalis A. St-Hil
S. reticulata Cambess.
Toulicia tomentosa Radlk.
Schizaeaceae
Anemia ferruginea Kunth
Scrophulariaceae
Buchnera lavandulacea Cham. & Schltdl.
Vochysiaceae
W
A
H
H
H
H
H
H
W
H
H
H
A
A
A
A
A
A
A
A
A
A
W
W
F
F
W
W
F
F
H
H
F
F
H
H
H
H
H
H
F
F
F
F
F
F
H
A
H
H
F
F
W
U
H
A
W
H
H
H
H
H
RA
RA
A
A
A
A
H
F
H
F
35
Qualea dichotoma Warm.
Q. grandiflora Mart.
Q. multiflora Mart.
Q. parviflora Mart.
Vochysia cinamommea Pohl
V. tucanorum Mart.
W
W
W
W
W
W
A
A
A
A
A
A
36
Table 2. Number of fruiting cerrado species and climatic factors in the Pé-de-Gigante
Reserve, Santa Rita do Passa Quatro, São Paulo State, southeastern Brazil (21º36-39’S,
47º36-38’W). ns P > 0.05, ** P < 0.01.
syndrome
Anemochorous species
Floater diaspore species
climatic factor
temperature
air relative humidity
rainfall
temperature
air relative humidity
rainfall
b
-2.17
-0.98
-0.06
-2.14
-0.67
-0.05
R2
0.32 ns
0.67 **
0.58 **
0.55 **
0.53 **
0.80 **
37
Table 3. Number of anemochorous species in the herbaceous and woody components of the
cerrado in the Pé-de-Gigante Reserve, Santa Rita do Passa Quatro, São Paulo State,
Southeastern Brazil (21º36-39’S, 47º36-38’W). (A = autogyro-diaspore species, RA =
rolling-autogyro-diaspore species, F = floater-diaspore species and U = undulator-diaspore
species).
component
herbaceous
woody
A
16
10
RA
13
13
F
54
6
U
4
7
38
Figure 1. Climatic diagram following Walter (1986), constructed from data obtained at DAEE
C4-107 meteorological station, located at Santa Rita do Passa Quatro (21º43’09”S,
47º28’38”W).
Figure 2. Percentage of anemochorous fruiting species throughout the year at the Pé-deGigante Reserve, Santa Rita do Passa Quatro, São Paulo State, southeastern Brazil (21º3639’S, 47º36-38’W).
Figure 3. Percentage of autogyro (a), rolling-autogyro (b), floater (c), and undulator (d)
diaspore species fruiting throughout the year in the Pé-de-Gigante Reserve, Santa Rita do
Passa Quatro, São Paulo State, Southeastern Brazil (21º36-39’S, 47º36-38’W).
39
Figure 1.
40
J
100
D
N
Anemochorous species
F
M
50
0
O
A
S
M
A
J
J
Figure 2.
41
J
a)
J
b)
100
D
100
D
F
N
0
O
N
M
50
0
M
A
J
J
J
J
J
c)
D
D
N
M
0
A
S
M
A
J
J
Figure 3.
50
F
50
O
J
d)
100
N
A
S
M
A
M
50
O
A
S
F
F
M
25
0
O
A
S
M
A
J
J
42
III. Capítulo 2
43
Divergência de diversidade de espécies a diásporos
anemocóricos em áreas de cerrado.1
1
Trabalho a ser submetido ao periódico Biotropica com o título “Divergence from Species to
Anemochorous Diaspore Diversity in Cerrado Sites”.
44
1
2
3
LRH: Massi and Batalha
4
RRH: Divergence from Species to Diaspore Diversity
5
6
Divergence from Species to Anemochorous Diaspore Diversity in Cerrado Sites.1
7
8
Klécia Gili Massi2 and Marco Antônio Batalha
9
10
Department of Botany, Federal University of São Carlos, PO Box 676, 13565-905, São
11
Carlos, SP, Brazil
1
2
Received_______; revision accepted__________.
Corresponding author: [email protected]
45
1
ABSTRACT – The cerrado presents a floristic and physiognomic variation, ranging from
2
grassland to tall woodland. Since the changes in the distribution of dispersal modes are
3
directly correlated with changes in vegetation structure, the index of divergence from species
4
to anemochorous diaspore diversity (IDD) is useful to compute the ecological similarity of
5
different communities. Our aim was to study the anemochorous diaspore spectra and IDDs in
6
cerrado physiognomies (campo cerrado, cerrado sensu stricto, and cerradão) in two Brazil
7
southern, disjoint sites and one cerrado physiognomy (cerrado sensu stricto) in a Brazil
8
central-western, core site. We conducted two anemochorous species surveys in a cerrado
9
sensu stricto physiognomy and compared with a phytosociological survey. The wind-
10
dispersed species were classified into autogyro, rolling-autogyro, floater, or undulator,
11
according to the diaspore morphology and aerodynamic behavior. We constructed the
12
anemochorous diaspore-types spectra and computed the IDDs of all physiognomies. We
13
applied a randomization test to test for differences among the IDDs, wich we find in one
14
disjoint site. The high and equal divergence of the cerrado physiognomies indicated that they
15
are ecologically similar and structurally homogeneous, at least when concerning wind-
16
dispersed species. When individuals were considered, the proportions of winged-dispersed
17
diaspores were different. Both physical and biotic factors influence the success or failure of
18
seed dispersal. In denser sites, vegetation reduces wind velocity in lower strata, constraining
19
dispersal of herbaceous species and heavy-seeded, wind-dispersed species require launching
20
from a tree or high climber.
21
22
Key words: anemochory, cerrado, dispersal, intrinsic diversity divergence, savanna, wind
23
dispersal.
24
46
1
RESUMO – O cerrado apresenta variação florística e fisionômica, indo desde uma fisionomia
2
campestre até uma florestal. Uma vez que as mudanças na distribuição de modos de dispersão
3
estão diretamente relacionadas a mudanças na estrutura da vegetação, o índice de divergência
4
de diversidade (IDD) de espécies a diásporos anemocóricos é útil para calcular a similaridade
5
ecológica de diferentes comunidades. Nosso objetivo foi estudar os espectros de diásporos
6
anemocóricos e os IDDs de fisionomias de cerrado (campo cerrado, cerrado sensu stricto e
7
cerradão) em duas áreas disjuntas ao sul do Brasil, e de uma fisionomia de cerrado (cerrado
8
sensu stricto) em uma área nuclear no centro-oeste do Brasil. Conduzimos dois levantamentos
9
de espécies anemocóricas e o comparamos com um levantamento fitossociológico. As
10
espécies anemocóricas foram classificadas em autogiro, autogiro-rotativas, flutuantes e
11
planadoras, de acordo com a morfologia e comportamento do diásporo no ar parado.
12
Construímos os espectros de tipos de diásporos anemocóricos e calculamos os IDDs de todas
13
as fisionomias. Aplicamos um teste de randomização para testar as diferenças entre os IDDs,
14
que encontramos em uma área disjunta. As divergências altas e iguais das fisionomias de
15
cerrado indicaram que elas são ecologicamente similares e estruturalmente homogêneas, ao
16
menos em relação às espécies dispersas pelo vento. Quando indivíduos foram considerados,
17
as proporções de diásporos dispersos pelo vento foram diferentes. Fatores físicos e bióticos
18
influenciam o sucesso ou o fracasso da dispersão. Em locais mais densos, a vegetação reduz a
19
velocidade do vento no estrato inferior, restringindo a dispersão das espécies herbáceas,
20
enquanto espécies anemocóricas de sementes mais pesadas, requerem o lançamento a partir de
21
árvores ou lianas.
47
1
One of the most enlightening approaches to the study of the adaptations of plants to certain
2
ecological conditions is that focused on the careful consideration of the morphological
3
features (Sarmiento & Monasterio 1983). In the case of dispersal of plants, morphological
4
traits of diaspores may affect mean potential dispersal distance (Augspurger 1986). Wind
5
plays one of the most important role in seed dispersal, not only in scattering seeds far from the
6
parent plant (Greene & Johnson 1989), but by reducing intraespecific competition and to
7
reach new habitats (Howe & Smallwood 1982).
8
9
As long as seed dispersal lays the template from which communities develop, its pattern is
commonly believed to influence community structure (Levine & Murrel 2003). Seed dispersal
10
may contribute to species coexistence through tradeoffs between colonization ability and
11
other characters across species, as well as through the slowing of competitive exclusion when
12
seeds fail to arrive (Nathan & Muller-Landau 2000). The potential to influence above-ground
13
vegetation is one of the most relevant functions of soil seed banks (Fenner 1985). Above- and
14
below-ground community compartments are strongly related in terms of abundance and
15
species composition, at least in a semi-arid system (Olano et al. 2005).
16
There is a considerable variation in the ways by which wind acts as a disperser of seed
17
(Ridley 1930). An aerodynamic classification of seed and fruit groups is a logical
18
consequence of describing general motion to the distinct subsets and it may be based almost
19
entirely on a division of species only according to the similarity of equivalent distributions of
20
mass and geometry (Burrows 1975, Harper 1977). Based upon observations of diaspores
21
aerodynamic behavior in still air and their morphology, Augspurger (1986) placed each of the
22
34 species observed into one of six classes: autogiro (A), rolling-autogyro (RA), floater (F),
23
undulator (U), helicopter (H) or tumbler (T).
24
A seed is released at a height where there is sufficient wind speed to transport (Soons et al.
25
2004a). Autogyro and rolling-autogyro species have structures that do not allow long-distance
48
1
flights and, even if wind is strong, height of release is more important in these cases; floater
2
diaspores, on the contrary, have high capacity of being transported, even in still air (Hensen &
3
Muller 1997) and may be sufficient for explaining long-distance dispersal events and
4
relatively rapid migration through open, suitable landscapes (Soons et al. 2004b). So, winged-
5
diaspores species (A, RA, H, T and U) tends to present a seed rain pattern more clumped than
6
plumed-diaspore species (F).
7
The index of intrinsic diversity divergence (IDD), which ranges from zero to one,
8
quantifies the species convergence of a given community into ecologically relevant groups
9
irrespective of their systematic (Ricotta et al. 2002). Ricotta et al. (2002) used Raunkiaer’s
10
(1934) life-forms to group the species, and the IDD was obtained by comparing the area under
11
the species diversity profile with the area under the corresponding life-form diversity profile.
12
When the IDD is applied, any classification of species into ecologically relevant groups may
13
be used (Ricotta et al. 2002). Since wind-dispersal is important to community dynamics
14
(Tackenberg et al. 2003, Soons et al. 2004a) and there are differences among wind-dispersed
15
diaspores (Augspurger 1986), we applied the IDD on the different wind-dispersed diaspores,
16
following Augspurger’s (1986) classification, in some cerrado communities.
17
The cerrado vegetation occupied originally ca. 23 percent of Brazil’s land surface, with a
18
core area in the Central Plateau and disjoint areas, such as those in the southeastern portion of
19
the country (Ratter et al. 1997). No species occurs at all cerrado sites, and the cerrado woody
20
flora includes many rare, characteristic species, together with accessory and ecotonal elements
21
(Ratter et al. 2003). These researchers proposed six cerrado floristic provinces, with distinct
22
floristic compositions: i) southern, ii) central, iii) central-western, iv) far-western, v) north-
23
eastern, and vi) Amazonian. The geographic distribution of cerrado species is limited (Gomes
24
et al. 2004) and there may be substitution of species belonging to the same genus or the same
25
family among the different cerrado floristic provinces (Bridgewater et al. 2004).
49
1
Besides the floristic variation, the cerrado presents a wide physiognomic variation, ranging
2
from grassland (campo limpo), through savannas (campo sujo, campo cerrado, and cerrado
3
sensu stricto), to tall woodland (cerradão). The cerrado flora has two components, a woody
4
one and an herbaceous one, which are distinct and antagonistic (Coutinho 1990). Winged
5
dispersal units prevail in the woody component, whereas plumed dispersal units are more
6
common in the herbaceous component (Gottsberger & Silberbauer-Gottsberger 1983). From
7
open to closed cerrado physiognomies, thus, the importance of winged diaspores (A, RA, and
8
U) should increase, whereas the importance of plumed diaspores (F) should decrease.
9
As long as there may be substitution of species belonging to the same genus or family
10
among different cerrado floristic provinces, we may expect that, for the same physiognomy,
11
even in different provinces, the proportions of winged-dispersed woody species and
12
individuals, and the IDDs are equal. Hence, we tried to anser the following question: are the
13
proportions of winged-dispersed diaspores and IDDs equal between cerrado sites? Moreover,
14
since changes in the distribution of dispersal modes are directly correlated with changes in
15
vegetation structure (Gottsberger & Silberbauer-Gottsberger 1983), we may expect, for a
16
given site, different proportions of winged-dispersed diaspores and different IDDs from open
17
to closed cerrado physiognomies. Hence, we also tried to answer the following questions:
18
does the proportion of winged dispersal units increase towards closed cerrado physiognomy?;
19
does the proportion of plumed dispersal units decrease towards closed cerrado physiognomy?;
20
and are the IDDs different among cerrado physiognomies?
21
22
METHODS
23
24
COMPARISON AMONG PHYSIOGNOMIES –We used data collected by Batalha & Mantovani
25
(2000). The site is the Pé-de-Gigante (Giant’s foot) Reserve, Santa Rita do Passa Quatro, São
50
1
Paulo State, southeastern Brazil, 21°36-39’S and 47°36-38’W, under Köppen’s Cwag’
2
climate, at 660 to 730 m high a.s.l., on Oxisol, with 1,269 ha, covered mainly by cerrado
3
(Pivello et al. 1998). From September 1995 to February 1997, they carried out a
4
phytosociological survey and sampled both the herbaceous and the woody components of
5
three cerrado physiognomies, campo cerrado, cerrado sensu stricto, and cerradão. In each
6
physiognomy, they placed ten quadrats, in which they sampled both the woody and the
7
herbaceous individuals, sampling 1,335 individuals in the campo cerrado, 1,086 individuals
8
in the cerrado sensu stricto, and 1,072 individuals in the cerradão.
9
We filtered the matrices, excluding all non-anemochorous species. Then, we classified
10
each anemochorous species, according to the movement of its diaspore while being dispersed,
11
into autogyro, rolling-autogyro, floater, or undulator (Augspurger 1986). To assess this, we
12
consulted taxonomic descriptions of the species and observed the fruits in lodged vouchers at
13
the University of São Paulo herbarium (SPF). We had, thus, data on abundance and type of
14
wind dispersal for all anemochorous species in three physiognomies. We tested for
15
differences in the proportions of wind-dispersal types by applying pair-wise comparisons with
16
the chi-square test (Zar 1999), considering either the number of species or the number of
17
individuals.
18
To determine the IDD of each physiognomy, first we computed the intrinsic diversity
19
profiles for species (αSP) and the intrinsic diversity profiles for anemochorous diaspore-types
20
(αDT), which are related, respectively, to the area under the species diversity profile and the
21
area under wind-dispersal type diversity profile. We constructed the diversity profiles
22
following the procedures of Patil & Tailie (1982) and determined the area under a given
23
profile as:
24
25
α = I × (N/2), in which
51
and i (1≤ i ≤ N) was the rank of the relative abundances pi arranged in descending order
1
2
(Ricotta et al. 2002). We calculated the index of intrinsic divergence (IDD) of each cerrado
3
as:
4
IDD = 1 – [(αDT - 0.5 )/(αSP - 0.5)]
5
We applied a randomization test (Manly 1997), with 5,000 permutations, to test whether
6
the IDDs of the campo cerrado, cerrado sensu stricto, and cerradão were significantly
7
different (α = 0.05).
8
9
COMPARISON AMONG SITES –We used data from three sites, a core cerrado site in the central-
10
western province and two disjoint cerrado sites in the southern province. The core site is
11
located in Alcinópolis (Mato Grosso do Sul State), Alto Araguaia and Alto Taquari (Mato
12
Grosso State), and Mineiros and Santa Rita do Araguaia (Goiás State), central-western Brazil,
13
in the southwestern extremity of the Brazilian Central Plateau. Regional climate is Aw
14
(Köppen 1948), humid tropical with wet summer and dry winter. This region was originally
15
covered mainly by cerrado vegetation, from open (campo limpo, a grassland savanna) to
16
closed (cerradão, a tall woodland) physiognomies, following Coutinho’s (1990)
17
classification. The first disjoint site is located in Itirapina Municipality, São Paulo State,
18
southeastern Brazil, approximately at 22°13’S and 47°51’W, 760m high above sea level. The
19
site is classified as cerrado sensu stricto following Coutinho’s (1990) classification. The
20
climate is Köppen’s Cwa, that is, macrothermic temperate with rainy summer and not
21
severely dry winter. The second disjoint site is located in the Pé-de-Gigante Reserve (see
22
description above).
23
In the core site, we randomly placed 32 lines, keeping at least 100 m between two of them.
24
In each line, we placed 15 points, 10 m apart one from the other, and sampled 60 woody
25
individuals with the point-quarter method (Müller-Dombois & Ellenberg 1974). So, in all
52
1
lines, we sampled 1,920 woody individuals. In the first disjoint site, there is a grid of 100
2
quadrats (each one with 25m2), where we randomly surveyed 50 quadrats at the middle of the
3
rainy season (March 2004), sampling 1595 woody individuals. In the second disjoint site,
4
Batalha & Mantovani (2000) sampled 687 woody individuals in the cerrado sensu stricto. We
5
defined the woody component as composed by the woody individuals with stem diameter at
6
soil level higher than 3 cm (SMA 1997).
7
Again we filtered the matrices, classified each anemochorous species, and tested for
8
differences in the proportions of wind-dispersal types by applying pair-wise comparisons with
9
the chi-square test (Zar 1999), considering either the number of species or the number of
10
individuals. We calculated the index of intrinsic divergence (IDD) of each cerrado site
11
(according to the description) and we applied a randomization test (Manly 1997), with 5,000
12
permutations, to whether the IDDs of the cerrado sensu stricto in the disjoint and core sites
13
were significantly different (α = 0.05).
14
15
RESULTS
16
17
COMPARISON AMONG PHYSIOGNOMIES – We sampled 36 anemochorous species in the campo
18
cerrado; 36, in the cerrado sensu stricto, and 35, in the cerradão (Table 1). Within this site,
19
16 species were common to the three physiognomies. The proportions of wind-dispersal types
20
were not different when we took into account the number of species, but, when considered the
21
number of individuals, they were (Table 2). The IDDs of the campo cerrado, cerrado sensu
22
stricto, and cerradão were, respectively, 0.868 (αSP = 8.072 and αDT = 1.496), 0.883 (αSP =
23
8.918 and αDT = 1.483), and 0.844 (αSP = 7.361 and αDT = 1.569) (Fig. 1). The IDDs were not
24
significantly different (campo cerrado vs. cerrado sensu stricto, p = 0.757; campo cerrado vs.
25
cerradão, p= 0.636; cerrado sensu stricto vs. cerradão, p= 0.443).
53
1
2
COMPARISON AMONG SITES – We sampled 28 anemochorous woody species in the core site;
3
14, in the first disjoint site (Itirapina), and 21, in the second disjoint site (Pé-de-Gigante) ; and
4
7 species were common to the three cerrado sensu stricto sites (Table 3). The proportions of
5
wind-dispersal types were not different when we took into account the number of species, but,
6
when considered the number of individuals, they were (Table 4). The IDDs of the cerrado
7
sensu stricto in the core site, Itirapina disjoint site and Pé-de-Gigante disjoint site were,
8
respectively 0.839 (αSP = 5.151 and αDT = 1.249), 0.589 (αSP = 2.95 and αDT = 1.506), and
9
0.827 (αSP = 5.137 and αDT = 1.301) (Fig. 2). The IDD comparisons with the first disjoint site
10
were significantly different (core vs. first disjoint site, p = 0.0364; core vs. second disjoint
11
site, p = 0.864; first vs. second disjoint site, p= 0.0468).
12
13
DISCUSSION
14
15
COMPARISON AMONG PHYSIOGNOMIES –Since the importance of trees and shrubs increases
16
from open to closed physiognomies (Coutinho 1978), we expected the proportions of
17
autogyro, rolling-autogyro, and undulator species also to increase in this direction and the
18
proportion of floater species to decrease. Nevertheless, the distributions of wind-dispersed
19
diaspore types were the same among the three cerrado physiognomies, at least when just the
20
species were considered. The hypothesis that the woody component increases towards closed
21
physiognomies, while the herbaceous component diversity decreases, was not confirmed by
22
Batalha et al. (2001). Because the difference between the IDDs was not significant, we may
23
postulate that there is a cerrado floristic unit with the ecotonal physiognomy containing
24
grassland and woodland elements.
54
1
Eiten (1977) stated that cerrado floristic composition changes gradually across the
2
physiognomic gradient. Therefore, the canopy cover, type of plant cover, and species
3
composition would to distinguish the diverse structure of the cerrado vegetation (Jepson
4
2005), from small and scattered to large and clumped trees (Goodland & Pollard 1973). On
5
the contrary, Coutinho (1978) considered the savanna formations as wide ecotones between
6
the cerradão and the campo limpo, since a great number of species present are common to
7
both theses extreme formations. Under the prevailing equilibrium viewpoint, communities are
8
assumed to be composed of species that differ in their resource use within that community
9
(Pickett 1980), which make possible their occurrence together (Whittaker 1965).
10
Possession of plumed seeds or fruits is rare in forests and frequent in open vegetations (Pijl
11
1969). Indeed, in a gallery forest within the Cerrado domain (Pinheiro & Ribeiro 2001) and in
12
a semi-deciduous forest in Barro Colorado Island (Augspurger 1986), the most abundant
13
diaspore class was the autogyro one. Tropical species show significant differences in seed
14
weight among trees, shrubs, and herbs (Rockwood 1985). In addition, species with large
15
flowers, fruits, and seeds tend to have large leaves, and one of the reasons could be to support
16
the fruit photosynthetically (Primack 1987). On the contrary, the herbaceous species recycle
17
the mineral elements internally by relocating them to the below-ground organs when the aerial
18
apparatus starts to dry out and before it is burned (Sarmiento 1984). To Ozinga et al. (2004)
19
the constraints of nutrient availability and seed weight may, in herbaceous species, lead to a
20
selection pressure against morphological adaptations, such as wings and plumes.
21
The proportions of winged-dispersed diaspores when individuals were considered were
22
different between the campo cerrado, cerrado sensu stricto, and cerradão. The occurrence of
23
a given physiognomy is maybe not defined by qualitative floristic changes, but by the
24
dominance of certain species that characterize the physiognomy (Oliveira & Moreira 1992).
55
1
The ecological processes and dynamics of the cerrado vegetation are the product of spatial
2
and temporal variability of several resources (Joly et al. 1999). If a location is characterized
3
by conditions within acceptable limits for a given species and contains all necessary
4
resources, the species can occur and persist (Begon et al. 1996).
5
The trees are supposed to be limited in growth by severe shortage of nutrients in the soil of
6
the grasslands (Goodland & Pollard 1973). Nascimento & Saddi (1992) concluded that the
7
high level of aluminum in a soil is a factor that could explain the greater number of Qualea
8
parviflora individuals. Moreover the differences in soil water availability between savannas
9
and dense hill forest were the principal environmental cause of variation in distribution of tree
10
species (Borchert 1994). Although most woody species are strongly fire-adapted, fires at too
11
frequent intervals damage them and favor the ground layer, thus producing more open
12
physiognomies (Gomes et al. 2004).
13
For a species to be dispersed, otimization would occur when dispersal agents presented
14
optimal conditions to act (Mantovani & Martins 1988). In denser sites, vegetation reduces
15
wind velocity in lower strata, constraining dispersal of herbaceous species (Oliveira &
16
Moreira 1992). The wind velocities necessary to transport most seeds away from the crown
17
constrain the number of seed dispersed (Clark et al. 2005). Seeds that are released from a
18
lower height above the vegetation are generally dispersed over shorter distances (Soons et al.
19
2004b). Heavy-seeded, wind-dispersed species require greater source densities to saturate
20
sites with seed (McEuen & Curran 2004), being launched from a tree or high climber (Pijl
21
1969).
22
High density of seeds deposited under the canopy may influence the fate of seeds and
23
subsequent patterns of plant recruitment (Clark et al. 2005). However, ants, rodents birds,
24
dungbeetles, and abiotic factors such as wind and water can move seeds after primary
25
dispersal (Vander Wall et al. 2005). Seeds deposited far from parent plants are likely to have
56
1
different survival and germination rates than those deposited nearby, and might have a
2
disproportionate influence on the resulting vegetation (Wang & Smith 2002). Nevertheless,
3
species without particular adaptations for long-range seed dispersal are regarded as very
4
sensitive to isolation (Hensen & Müller 1997).
5
COMPARISON AMONG SITES – The proportions of winged-dispersed species were equal among
6
a core cerrado site and two disjoint cerrado sites, with the same physiognomy. In the past, the
7
extent of tropical forest increased in warmer, wetter periods and contracted as savanna
8
dominated the vegetation in the cooler and drier periods; today, the present distributions of
9
both plant and animal species provide evidence of the positions once occupied by these
10
11
“tropical islands in a sea of savanna” (Begon et al. 1996).
Due to its extension, environmental heterogeneity, and proximity to other tropical
12
vegetation types, the cerrado has a high diversification at the level of species; and most of
13
these species exhibit morphological and physiological adaptations to the climatic and edaphic
14
conditions that prevail in the region (Joly et al. 1999). Each of these regions has species that
15
are endemic to them, but in many cases these species are part of a closely related species
16
complex (Prado & Gibbs 1993). Also there are too many species having wide distribution,
17
nearly occurring in whole cerrado domain (Leitão-Filho 1992).
18
A high IDD value of a given community indicates that such community is structurally very
19
homogeneous, because most species diversity is distributed in few classes (Ricotta et al.
20
2002). In the case of the core and one disjoint sites (Pé-de-Gigante Reserve), they are
21
structurally homogeneous due to the prevalence of one anemochorous diaspore-type and with
22
the others poorly represented. The Itirapina disjoint site showed its species diversity well
23
distributed in diaspore classes. As long as IDD is a measure to quantify the ecological
24
similarity of different communities (Ricotta et al. 2002), we may conclude that the core and
25
Pé-de-Gigante disjoint sites are ecologically similar, and both are ecologically different from
57
1
Itirapina. The cerrado sensu stricto from Itirapina is opened, with soil exposure and this can
2
be explained by several perturbation factors (Pagano et al. 1989). We postulated that this
3
would favoured any diaspore type.
4
On the contrary, when individuals were considered, the proportions of winged-dispersed
5
diaspores were different. Even when there is a large number of common species between
6
sites, the size of the species population is very variable from place to place (Felfili et al.
7
2004). The dominance of species and the number of their individuals varies strongly in
8
different cerrado sites; this is certainly influenced by different altitudes (Gottsberger &
9
Silberbauer-Gottsberger 1983), geomorphology, soil physic and chemical features, fire
10
frequency (Coutinho 1978), climatic factors, herbivory, and human disturbances (Miranda et
11
al. 2002). Both physical and biotic factors influence the success or failure of seed dispersal
12
(Howe & Westley 1986).
13
In an Australian savanna, sexual regeneration of the species is disadvantaged by current
14
burning practices because both seed supply and the number of microsites are reduced
15
(Setterfield 2002). The losses of reproductive structures due to fire must be important, mainly
16
in smaller trees (Garcia-Nuñez et al. 2001). However, dispersal by wind may be dependent on
17
casual events, such as occasional whirlwinds or burnings that clear the vegetation and allow
18
dispersal over longer distances (Coutinho 1978). Hoffmann (1998) concluded that current fire
19
regimes must cause a shift is savanna species composition, favoring species capable of
20
vegetative reproduction.
21
The substrate available for deposition might also affect seed-dispersion patterns – that is,
22
seeds might be preferentially deposited or retained on some microsites. For example, wind-
23
dispersed seeds might be more likely to end up on rough surfaces (Nathan & Muller-Landau
24
2000). Johnson & Fryer (1992) studying the wind dispersal of samaras, concluded that on
58
1
rougher surfaces, seeds remained stationary for a sufficient length of time to imbibe water to
2
start the germination sequence.
3
We think that are important the comparisons between individuals and species. To
4
Whittaker (1965), comparing number of species is the most convenient way to compare
5
diversities in different communities as it seems inappropriate to compare on the same scale
6
individuals as disparate in size as trees and herbs.
7
8
ACKNOWLEDGEMENTS
9
10
We thank Igor Aurélio da Silva for his help in data analyses.
11
12
LITERATURE CITED
13
14
15
16
AUGSPURGER, C. K. 1986. Morphology and dispersal potential of wind-dispersed diaspores of
neotropical trees. American Journal of Botany 73(3): 353-363.
BATALHA, M. A., AND W. MANTOVANI. 2000. Reproductive phenological patterns of cerrado
17
plant species at the Pé-de-Gigante Reserve (Santa Rita do Passa Quatro, SP, Brazil): a
18
comparison between the herbaceous and woody floras. Revista Brasileira de Biologia
19
60: 129-145.
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21
22
23
24
25
___, ___, AND H. N DE MESQUITA JÚNIOR. 2001. Vegetation structure in cerrado
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65
1
TABLE 1. Percentage of autogyro, rolling-autogyro, undulator, and floater diaspore
2
individuals and species in the campo cerrado, cerrado sensu stricto and cerradão of the Pé-de-
3
Gigante Reserve.
physiognomy
campo cerrado
Species
Individuals
cerrado sensu stricto
Species
Individuals
cerradão
Species
Individuals
4
total
autogyro (%) rolling-autogyro (%) undulator (%) floater (%)
36
262
36.1
31.7
22.2
15.6
8.3
12.2
33.4
40.5
36
304
41.7
42.8
27.8
22.7
16.6
25.3
13.9
9.2
35
361
37.2
33.0
31.4
33.0
11.4
28.2
20.0
5.8
66
1
TABLE 2. Comparisons of wind-dispersed diaspore spectra among physiognomies of the Pé-
2
de-Gigante Reserve.
Comparison
campo cerrado vs. cerrado sensu stricto
campo cerrado vs. cerradão
cerrado sensu stricto vs. cerradão
3
NS = P > 0.05; ** P < 0.01; *** P < 0.001
species
χ2 = 4.247 NS
χ2 = 1.919 NS
χ2 = 0.910 NS
Individuals
χ2 = 78.796 ***
χ2 = 125.330 ***
χ2 = 13.489 **
67
1
TABLE 3. Percentage of autogyro, rolling-autogyro, undulator, and floater diaspore
2
individuals and species in the cerrado sensu stricto of the core (central-western Brazil) and
3
disjoint sites (southeastern Brazil.
sites
core site
Species
Individuals
Itirapina disjoint site
Species
Individuals
Pé-de-Gigante disjoint site
Species
Individuals
4
total
autogyro (%) rolling-autogyro (%) undulator (%) floater (%)
28
427
21.4
52.0
42.9
29.0
25
11.0
10.7
8.0
14
329
35.7
36.5
42.9
32.2
14.3
25.5
7.1
5.8
21
171
38.1
39.8
23.8
15.8
23.8
41.5
14.3
2.9
68
1
TABLE 4. Comparisons of wind-dispersed diaspore spectra among sites of cerrado sensu
2
stricto physiognomy.
Comparison
core site vs. Itirapina disjoint site
core site vs. Pé-de-Gigante disjoint site
Itirapina disjoint site vs. Pé-de-Gigante disjoint site
3
NS = P > 0.05; *** P < 0.001
species
χ2 = 1.352 NS
χ2 = 2.553 NS
χ2 = 1.738 NS
Individuals
χ2 = 34.400 ***
χ2 = 74.619 ***
χ2 = 22.926 ***
69
1
FIGURE 2. Intrinsic diversity profile for species and anemochorous diaspore-types relative
2
abundances of the campo cerrado (a), cerrado sensu stricto (b) and cerradão (c) of the Pé-de-
3
Gigante Reserve.
4
5
FIGURE 1. Intrinsic diversity profile for species and anemochorous diaspore-types relative
6
abundances of the cerrado sensu stricto of Itirapina (a) and Pé-de-Gigante (b) disjoint sites
7
(southeastern Brazil) and the core site (c) (central-western Brazil).
70
b)
Cumulative number of species and
anemochorous diaspore-types
a)
Cumulative number of species and
anemochorous diaspore-types
1
Cumulative number of species and
anemochorous diaspore-types
c)
32
24
16
8
0
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
32
24
16
8
0
35
30
25
20
15
10
5
0
Cumulative relative abundance
Species diversity
Diaspore diversity
2
71
b)
Cumulative number of species and
anemochorous diaspore-types
b)
Cumulative number of species and
anemochorous diaspore-types
1
Cumulative number of species and
anemochorous diaspore-types
c)
14
7
0
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
21
14
7
0
28
21
14
7
0
0.8
0.9
Cumulative relative abundance
Species diversity
Diaspore diversity
1
72
IV. Conclusão Geral
73
Conclusão Geral
Com este trabalho chegamos às seguintes conclusões:
•
a frutificação das espécies anemocóricas na Reserva Pé-de-Gigante (SP), foi
estacional; logo a estação seca favorece a dispersão dos diásporos anemocóricos, que
são secos, corroborando Mantovani & Martins (1988), Miranda (1995), Batalha et al.
(1997) e Batalha & Martins (2004);
•
o número de espécies anemocóricas frutificando relacionou-se negativamente com a
precipitação e com a umidade relativa. Na estação seca, frutos dispersos pelo vento
desidratam e muitas espécies trocam suas folhas, favorecendo a dispersão dos
diásporos;
•
os grupos de espécies com diásporos autogiro, autogiro-rotativos e planadores tiveram
períodos de frutificação bem distribuídos ao longo do ano. O grupo de espécies com
unidade de dispersão flutuante frutificou estacionalmente com pico na estação seca,
relacionando-se negativamente à temperatura, umidade relativa do ar e precipitação.
Isso pode ser devido à restrições filogenéticas, porém espécies com sementes
flutuantes devem concentrar seus períodos de frutificação durante a estação seca,
devido ao comportamento hidrofóbico das plumas (Hensen & Muller 1997);
•
os componentes herbáceo-subarbustivo e arbustivo-arbóreo apresentaram maior
proporção de espécies com diásporos flutuantes e planadores, respectivamente.
Portanto, diásporos plumados e alados devem prevalecer em fisionomias abertas e
fechadas, respectivamente;
74
•
as fisionomias de cerrado sensu stricto, nas áreas nuclear e disjuntas, apresentaram a
mesma distribuição de espécies dentro dos grupos de tipos de diásporo anemocórico;
logo a distribuição de espécies entre os diferentes tipos de diásporos anemocóricos
entre as espécies deve se manter independente da província geográfica em que a
comunidade se encontre;
•
o número de indivíduos dentro dos grupos de tipos de diásporo anemocórico variou
de uma área para outra; logo, pode haver restrições à dispersão ou uso diferenciado
dos recursos disponíveis;
•
as fisionomias campo cerrado, cerrado sensu stricto e cerradão de uma área disjunta
apresentaram a mesma distribuição de espécies dentro dos grupos de tipos de diásporo
anemocórico; logo, a distribuição de tipos de diásporos anemocóricos entre as espécies
deve se manter independentemente da fisionomia de cerrado;
•
quando a abundância das espécies foi considerada, as proporções de tipos de diásporos
anemocóricos variaram entre as fisionomias de uma mesma área; logo, processos
ecológicos que atuem em escalas menores e que influenciem o tamanho das
populações afetam a distribuição de tipos de diásporos anemocóricos na comunidade.
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