**Genetic Structure and Diversity of Brazilian Tree Species from Forest Fragments and Riparian Woods**

Danielle Cristina Gregorio da Silva et al.\* *Universidade Estadual do Norte do Paraná Brazil* 

### **1. Introduction**

390 Genetic Diversity in Plants

Chakraborty, R. (1993). A class of population genetic questions formulated as the generalized occupancy problem. *Genetics*, Vol. 134, No. 3, (July 1993), 953-958,1061- 4036 Diskin, M., Steiner, C., & Hebard, F. (2006). Recovery of American chestnut characteristics

Elliot, K., & Swank, T. (2008). Long-term changes in forest composition and diversity following

Huang, H., Dane, F., & Kubisiak, T. (1998). Allozyme and RAPD analysis of the genetic

Jacobs, D. (2007). Towards development of silvical strategies for forest restoration of

Jansen, P., Bongers, F., & Van der Meer, P. (2008). Is farther seed dispersal better? Spatial

Nathan, R., Schurr, F., Spiegel, O., Steinitz, O., Trakhtenbort, A., & Tsoar, A. (2008).

Paillet, F. (2002). Chestnut: history and ecology of a transformed species. *Journal of* 

Pierson, S., Keiffer, C., McCarthy, B., & Rogstad, S. (2007). Limited reintroduction does not

Primack, R. (May 1, 2010). *Essentials of Conservation Biology* (5th edition), Sinauer Associates,

Primack, R., & Miao, S. (1992). Dispersal can limit local plant distribution.*Conservation* 

Rogstad, S., & Pelikan, S., (September 2, 2011). *Genetic Diversity in Establishing Plant* 

Russel, E. (1987). Pre-blight distribution of *Castanea dentata* (Marsh.) Borkh. Bulletin *of the Torrey Botanical Club,* Vol. 114, No. 2, (April 1987), 183-190, 0040-9618 Stilwell, K., Wilbur, H., Werth, C., & Taylor, D. (2003). Heterozygote advantage in the

*Plant Ecology,* Vol. 197, No. 2, (September 2007), 155-172, 1573-5052

*Conservation,* Vol. 137, No. 4, (July 2007), 497-506, 0006-3207

No. 6028, (April 2011), 424-425, 1095-9203

2007), 420-429, 1526-100X

978-0-87893-640-3, Sunderland MA

157808721X, New Hampshire.

No. 2, (February 2003), 207-213, 1537-2197

23, No. 11, (November 2008), 638-647, 0169 -5347.

*Biogeography,* Vol. 29, No. 10-11, (2002), 1517-1530, 1365-2699

*Biology,* Vol. 6, No. 4. (December 1992), 513–519, 0888-8892

1471-2229

1127

(*Castanea dentata)* and Chinese chestnut (*Castanea mollisima)* in response to the chestnut blight infection. *BMC Plant Biology,* Vol. 2009, No. 9, (May 2009), 513-958,

following hybridization and backcross breeding to restore blight-ravaged *Castanea dentata. Forest Ecology and Management,* Vol. 223, No. 1-3, (March 2006), 439-447, 0378-

early logging (1919-1923) and the decline of the American chestnut (*Castanea dentata).* 

diversity and geographic variation in wild populations of the American chestnut (Fagaceae). *American Journal of Botany*, Vol. 85, No. 7, (July 1998), 1013-1021, 1537-2197

American chestnut (*Castanea dentata)* using blight resistant hybrids. *Biological* 

patterns of offspring mortality in three rainforest tree species with different dispersal abilities. *Ecography*, Vol. 31, No. 1, (February 2008), 43-52, 09067590 Lawrence, M., Marshall, D., Davies, P. (1995). Genetics of genetic conservation. I. Sample size when collecting germplasm. *Euphytica*, Vol. 84, No. 2, (June 1995), 89-99, 00142336 Merritt, D., & Dixon, K. (2011). Restoration Seed Banks – A Matter of scale. *Science*, Vol. 332,

Mechanisms of long-distance seed dispersal. *Trends in Ecology and Evolution,* Vol.

always lead to rapid loss of genetic diversity: An example from the American chestnut (*Castanea dentata:* Fagaceae). *Restoration Ecology,* Vol. 15, No. 3, (September

*Populations: Founder Number and Geometry* (1st edition), Science Publishers,

American Chestnut, *Castanea dentata* (Fagaceae). *American Journal of Botany*, Vol. 90,

Historical patterns of human occupation in Brazilian Neotropical Region, featured by deforestation for urbanization, economic exploitation and agriculture, have changed the Atlantic Forest landscape to a collection of fragments. Nowadays this biome is characterized for being highly fragmented but still possessing one of the highest rates of species diversity in the world.

Understanding the genetic structure of populations that occur in forest remnants is fundamentally necessary to establish efficient strategies for the re-composition, management, and conservation programs. For such, it is necessary not only to understand the genetic diversity of a species, but also, how this diversity is distributed within and between forest populations. Notably, a considerable part, if not the majority, of Brazilian Atlantic Forest fragments are linked to rivers or streams, once the policy applied in Brazil regarding conservation in agricultural areas favours the maintenance of legal reserves in proximity of water sources. The vegetation of river margins are subjected to flooding, a strong limiting factor which can lead to local adaptation. These ecological and landscape characteristics may have important outcomes to the genetic diversity of tree populations.

In this chapter, we assembled information from review and research papers of impact in this study area intending to raise knowledge to assist conservation initiatives of Brazilian Atlantic Forest fragments and riparian woods. We plan to broach fundamental concepts regarding the historical fragmentation process in Brazilian Neotropical Region, the effects of fragmentation upon the genetic diversity of forest remnants, and the local adaptation to seasonally variable river levels. This discussion is not intended to be a summary of the existing literature in the theme, but to address important information concerning genetic diversity of neotropical tree species, focusing in the results of eleven years of research on species frequently used in reforestation of legal reserves in Southern Brazil.

<sup>\*</sup> Mayra Costa da Cruz Gallo de Carvalho1, Cristiano Medri2, Moacyr Eurípedes Medri3, Claudete de Fátima Ruas3, Eduardo Augusto Ruas3, Paulo Maurício Ruas3

*<sup>1</sup>Empresa Brasileira de Pesquisa Agropecuária, Brazil* 

*<sup>2</sup>Universidade Estadual do Norte do Paraná, Brazil* 

*<sup>3</sup>Universidade Estadual de Londrina, Brazil*
