**4. Discussion**

The BNP was established in an area of the Cerrado biome, with native ecosystems of grasslands, savannas, and forests. However, this area was previously occupied by farms, dwellings; exotic species were cultivated in it. In addition, its proximity to (Novacap's nursery, created in 1971 to produce seedlings of native and exotic species) aided, and continues to aid, colonization of the park by propagules of exotic species used mostly for urban landscaping. This is the case of the eucalyptus planted to form the windbreak located on the boundary between the park and the nursery [27].

Data generated by this research showed that eucalyptus populations in the BNP grew and dispersed since 1970s and, therefore, behaved as invasive. The lack of control and management reinforced this process. Most of the identified individuals are reproductively active and population density is high.

Regarding management options employed by the BNP staff to reduce or neutralize the risk and the influence of exotic species (the groups of eucalyptus within the park and in the windbreak), the most suitable one is eradication, because of the size of the groups [25]. According to observations of other groups of eucalyptus located inside the park, we found that the cutting method used to control the species does not result in eradication. The girdling method, observed in some individuals located elsewhere in the park, did manage to kill them. Therefore, we assume that girdling may work for the individuals studied.

On the other hand, the BNF displays a dominant anthropic landscape composed of stands of planted eucalyptus and pine trees – two exotic species with strong invasive potential. Although the BNF is managed under the same general regulations as national parks (Law 9,985, of July 18, 2000, and Decree 4,340, of August 22, 2002), its conservation goals differ from those of the BNP. While national parks, as "fully protected" areas, seek the preservation of nature, biodiversity, and ecosystems, national forests, as "sustainable use" areas, seek to combine conservation with the use of natural resources. To do so, national forests can plant and harvest commercially valuable exotic species, to the detriment of native species. In the case of the BNF, the area formerly occupied by Cerrado (open, savanna-like vegetation) was occupied by dense lines of tall pine and eucalyptus forests. This happened in the 1980s. Native flora was removed, and fauna was dispersed from the BNF area. Losses of biodiversity and native landscapes are obvious consequences. There are no gains in terms of environmental conservation.

Areas I and II of the BNF may be vectors of contamination of native vegetation inside the BNP, given their mutual proximity (**Figure 3**). According to the BNF's management plan, its dominant vegetation consists of pines and eucalyptus trees that lack proper cultivation practices is, a fact that increases the risk of invasion of these species into the BNP area [21]. Most of the BNF's Area I, which is closest to the park, is covered by eucalyptus plantations.

Although the park has followed its objectives consistently, the neighbouring BNF is a potential threat to its biodiversity by acting as a vector of contamination by exotic species. From the viewpoint of regional conservation, the BNF is a potential agent of environmental degradation than a protected area. The proximity of the BNF to the BNP generates no synergy or gains in terms of biodiversity protection. Brazilian PA law does allow the formation of "mosaics". Mosaics are management models, predicted by Law 9,985 of July 18, 2000, and Decree 4,340 of August 22, 2002, which seek to integrate the management of different types of neighbouring protected areas. However, we consider them to be unfeasible in the cases of national forests covered by plantations of exotic species which are located next to fully protected PAs. Environmental planning should always consider species with strong dispersion potentials as a risk and, therefore, should define containment measures in the same way as it does in the case of private commercial plantations located in the buffer zones of PAs, as predicted by law.

#### **5. Conclusion**

Field surveys conducted in the BNP led to the conclusion that the studied groups of eucalyptus have invasive characteristics. The BNP area adjacent to Novacap's nursery hosts a well-established and dispersing group of eucalyptus. If not controlled, it may become a very serious problem for the park. The populations of eucalyptus originated from windbreak propagules, located near the nursery, should

#### *Undesirable Neighbours: Eucalyptus and Protected Areas DOI: http://dx.doi.org/10.5772/intechopen.99831*

be eliminated. Eradication is feasible due to the size of the groups and to their initial stage of dispersion. Managing these populations is essential for the BNP to fulfil its objectives, among which the preservation of biodiversity is paramount.

Area I of the BNF, close to BNP, with its plantations of eucalyptus and pines, is an obvious contamination risk, even though the risk so far has not been strong. This may be due to the combination of wind velocity and wind direction with the timing of seed release. This combination does not favour dispersion from Area I of the BNF to the BNP. However, this section of the BNP, on account of its proximity to the BNF, should become a prime target for the monitoring and control of exotic species in the park. On the other hand, eucalyptus propagules from the nursery windbreak, as well as remaining populations of Area II of BNF, have their dispersion towards the BNP favoured by wind speed and direction in the month of January, coinciding with peak seed release. This mode of dispersion is corroborated by the data obtained in this study.

In terms of control and management of eucalyptus in the BNP, this work points to the necessity of strengthening (i) measures of species eradication inside the unit and (ii) the management and planning of the landscape surrounding the park. Concerning the BNF, its proximity to the park jeopardizes the park's preservation goals, even though the BNF is an officially created and managed PA. Therefore, regardless of the formal categories of land use and occupation, vectors of contamination by exotic species can come from the most varied and even unexpected sources, such as a neighbouring PA.
