Floristic composition of an urban coastal forest fragment

The urban areas have suffered with the loss in their biodiversity along the years due to the decrease of green areas by civil construction or by the urban population growth. Therefore, this work aimed at registering the angiosperms diversity in an urban forest fragment at the Itaperi Campus of the State University of Ceará, Fortaleza, Brazil. The sampling was carried out from May/2018 to April /2019 through walks during the rainy and dry seasons. 160 species distributed in 128 genera and 49 families were registered. Fabaceae (27 spp.), Asteraceae (13 spp.), Convolvulaceae and Malvaceae (11 spp. each), Rubiaceae e Poaceae (9 spp. each), and Euphorbiaceae (8 spp.) were the richest families, accounting for 55% of the sampled flora. The herbaceous plants (36.65%) were the most represented habit after which the sub-shrubs and shrubs (17,50% each), arboreal (16,25%) and climbing plants (13.12%) were classified. Among the total species 94.37% are natives, 15,62% are endemic to Brazil and 5,62% are exotic. Of the identified species, 10 spp. are in the Red List of the Flora Conservation National Center and 30 spp. are in the Red List of the International Union for the Conservation of Nature. It can be concluded that the studied fragment has an important richness of plant species in an urban area, therefore it is necessary to create a Conservation Unity and a management plan in order to guarantee the conservation of the area.


Introduction
Great areas of the Earth surface are being altered by human activities (Pardini et al. 2017).The lost and fragmentation of the habitats are the main causes of species extinction besides increasing the fragment vulnerability to the invasion of exotic and native ruderal species (Primack & Rodrigues 2001;Mullu 2016).
Currently, all the vegetal formations are altered by anthropic actions in a bigger or smaller degree especially due to agricultural and cattle raising activities and the industrialization and urbanization impacts, leaving only a few patches where the original vegetation is present (Silva 2019).The urban areas, especially in big metropolises, have suffered along the years with their biodiversity loss due to the decrease in the green areas by civil construction or by the urban population growth (Alencar et al. 2017).
Big Brazilian metropolises as the city of Fortaleza, capital of Ceará state, Brazilian Northeast, the 5 th biggest metropolis in the country, has 312,353 km² of urbanized area and an estimated population of 2,669,342 inhabitants (IBGE 2019).Located in the Atlantic coast, Fortaleza has its native forest vegetation reduced and considerably degraded due to urban expansion causing an irrecoverable damage to the fauna and flora biodiversity of the region.Likewise, the hydric resources suffer with the deforestation of the riparian vegetation which has a crucial role in feeding and sheltering the local fauna (Fortaleza 2003).
In extremely altered and degraded landscapes, the remaining vegetational becomes even more important.The coastal vegetation in Ceará presents a richness of species and aspects considered a diversified vegetational collection subjected to very differentiated ecological conditions, from dunes vegetation, semideciduous forest, through coastal cerrados to mangroves (Moro et al. 2015).
The coastal ecosystems suffer a strong anthropic pressure in Fortaleza, for example, more than 90% of the original vegetation has already been lost (Fortaleza 2003;Moro 2020).There are only few patches of native vegetation left and they are in urgent need of public politics to establish the areas protected by Conservation Units (Moro et al. 2011).
Allied to the vegetal biodiversity conservation, the floristic surveys are fundamental and provide subsidies to the conservation of the remaining ones that host a high richness of native and endemic species, mainly for the Caatinga phytogeographical domain that has less than 2% of its territory protected by conservation units (Fernandes et al. 2020).Thus, the knowledge about the biodiversity present in the remaining vegetation of the region is increasingly necessary besides the importance of the beneficial effects that the contact with nature generates to human health, especially in the big metropolises where the vegetation alleviates the impacts caused by the anthropic action (Melo et al. 2011;Amato-Lourenço et al. 2016;Pereira et al. 2018).
Therefore, the present work aimed at registering the angiosperms diversity in an urban forest fragment at the Itaperi Campus of the State University of Ceará (UECE), in Fortaleza, Ceará, as well as verifying which taxon are native to Brazil and which are exotics, with habit information, endemism, new registers and conservation status information in order to broaden the knowledge about the local flora and evaluate its potential for the conservation of the local biodiversity.

Study area
The floristic survey was made in an urban fragment of coastal forest located inside the Itaperi Campus of the State University of Ceará (UECE).The fragment is located in the municipality of Fortaleza, state of Ceará, Northeastern Brazil.The study area extends across 25.83 ha, a varying altitude from 15 to 31 m, located between the geographic coordinates 03°47'49"S, 38°33'21"W and 03°48'10"S, 38°33'35"W (Fig. 1).
The climate in the region is characterized as Tropical Warm and Sub-humid presenting an average rainfall of 1.338 mm with an average annual temperature from 26 to 28 o C, with rainy season from January to May.Its relief is classified as Coastal Plain and Pre-coastal Semideciduos Forest, with the presence of Marine Quartzite Sands, Solodic Planosoil, Red-Yellow Podzolic and Solonchak soils types (IPECE 2018).According to Moro et al. (2015), the coastal region of Ceará has a recent geological origin (Tertiary-Quaternary), with a diversity of vegetation types, such as Semifixed and Mobile Dunes Vegetation, Fixed Dunes Vegetation, Coastal Semideciduos Forest (Mata de Tabuleiro), Cerrado and Coastal Forested Savanna, Cerradão.
The typical vegetation of the study area is Coastal Semideciduos Forest, under the influence of Barrier Formations which comprises a Seasonal Rodriguésia 72: e00582020.2021 Semi-deciduos Forest of medium size that gathers species from the Caatinga and Cerrado phytogeographical domains, although they are very anthropized (Castro et al. 2012;Moro et al. 2015).
In order to elaborate a map of the study area a QGIS version 3.4.8software was used and the vegetation classification followed the phytoecological units available at the IPECE website (<http://www.ipece.ce.gov.br/>) and described by Figueiredo (1997).

Floristic survey
The floristic samplings were carried out from May/2018 to April/2019 during the dry and rainy seasons.The walking method was the one used (Filgueiras et al. 1994) in all the study area (Fig. 2).All the fertile plant species (i.e.: those with flowers and/or fruit) were photographed in the field and collected for taxonomic identification.The samples were herborized according to the usual botanic techniques (Mori et al. 1985) and deposited in the Prisco Bezerra Herbarium (EAC) of the Federal University of Ceará (UFC).
The identifications were carried out from specialized bibliography (Barroso et al. 2004;Souza & Lorenzi 2019), key identifications, experts' consultation, comparison with exsiccates of the specimens deposited in the EAC herbarium and BFG (2018) and SpeciesLink (CRIA 2020) websites.The origin, endemism and new registers information are in agreement with the data from the BFG website (2018).The registered species were classified in families according to APG IV (Angiosperm Phylogeny Group 2016), except for the Turneraceae family, which was considered a separate family of Passifloraceae, according to Souza & Lorenzi (2019).To determine the Fabaceae subfamily the Leguminosae Phylogeny Working Group (LPWG 2017) identification key was used.The taxon names and authors are in agreement with The International Plant Names Index (IPNI 2020).

Results and Discussion
A total of 160 angiosperms species were registered distributed in 128 genera and 49 families  ).The floristic list produced in this study had, practically, all species identified up to a specific level, with the exception of two species that were identified up to their generic name.The richness of species found in this study is bigger than the one surveyed in the UECE urbanized area by Oliveira et al. (2020)  It was verified that 39 species are classified by their conservation status as LC (Least Concern) but the Campomanesia aromatica (Aubl.)Griseb.specie is considered vulnerable (VU) (CNCflora 2016; IUCN 2020).
Among the sampled species, the presence of 37 spp. in the Red Lists (CNCFlora 2016; IUCN 2020) were verified, classified regarding their conservation status as Least concern (LC) and the Campomanesia aromatica (Aubl.)Griseb.(Myrtaceae) specie was classified as vulnerable (VU) (IUCN 2020), probably due to its use as wood for fence building as cited by Chaves et al. (2014).
The coastal urban fragment of UECE, despite the presence of exotic species, is predominantly composed by a native vegetation besides presenting species endemic to Brazil and the Caatinga and Cerrado phytogeographical domains.It was also considered as a very anthropized area for its location being inside the UECE campus and by various anthropic activities carried out in the fragment surroundings.However, the area has an elevated ecologic and self-sustainability potential of the local species which is important for the vegetal biodiversity conservation in Fortaleza municipality.In addition to sheltering many vegetal species it also presents many animal species, and according to Carmo et al. (2018), the Itaperi campus presents itself as a haven for the wild fauna, as shelter, food resource and a favorable environment for reproduction, for example, the Boa constrictor (Linnaeus, 1758) snake, popularly known as jiboia.The creation of a Conservation Unit (CU) in the area will be of extreme importance to keep the native species and the ecological processes which are still present.Furthermore, this area is a source for academic researches, such as scientific initiation, masters degree studies and projects towards the environmental education.Menezes et al. (2010) states that Ceará state has 81 protected areas with the potential to maintain the fauna and flora species, however, these areas comprise only 7,7% of the state territory.Twenty-two of these are managed by the State Environmental Superintendency (SEMACE), where there are twelve Environmental Protection Areas, three State parks, two Natural Monuments and one Area of Relevant Ecological Interest (SEMACE 2010).
Thus, it is recommended that the study area be protected and the creation of a municipal Area of Relevant Ecological Interest (ARIE), a Sustainable Use Conservation Unit, seems to be the more indicated for areas with little extension or no human occupation according to the Article 16 Law 9.985/2000.Therefore, considering that the urban coastal forest fragment studied has a small extension of vegetation with the presence of diverse fauna and flora species, the ARIE creation is justified.
So, it can be concluded that the studied fragment has an important richness of native plants species being of extreme importance to be conserved in the Fortaleza municipality urban area.Its flora is composed by various native species common to the Ceará coast besides presenting many species of different vegetation types, showing the local heterogeneity and ecological potentiality.Regarding the exotic species, there is a need to control and manage the non-native species in the area.Despite being very anthropized and the target of many human activities, the study area is feasible for the creation of a Conservation Unit and a management plan to guarantee the area conservation.Therefore, this study can contribute with the future decisions related to its management, besides presenting the floristic diversity of the studied area.

Figure 1 -
Figure 1 -Location of the urban coastal forest fragment at the Itaperi Campus of the State University of Ceará, Fortaleza-CE.

Figure 2
Figure 2 -a-f.Physiognomies of the urban coastal forest fragment at the Itaperi Campus of the State University of Ceará, Fortaleza-CE -a.aquatic vegetation of the ponds and swamps; b-c.vegetation of Coastal Semideciduos Forest; d-f.Vegetation of Coastal Cerrado.

Table 1 -
Castro et al. (2011) species;Diogo et al. (2014), in turn, registered 116 species registered in the Semideciduos Forest in the Pici Campus of the Federal Universtiy of Ceará (UFC);Castro et al. (2011)registered 93 species present on the free areas of the rectory of the Fortaleza University (Unifor); andMoro et  al. (2011)registered 151 species in the savanna vegetation fragment belonging to the Brazilian Telegraph Post Company and the Brazilian Army; all in Fortaleza urban zone.List of angiosperm species registered of the urban coastal forest fragment at the Itaperi Campus of the State University of Ceará, Fortaleza-CE, including family/species, habit (H = herbaceous; SU = sub-shrub; S = shrub; T = tree; C = climber), species endemic to Brazil (END), Prisco Bezerra Herbarium voucher number (EAC), collector and collector number (COLLECTOR, CN).* = exotic species; ¹ = species of the Red List of the National Center for Flora Conservation (CNCFLORA 2016) classified as Least Concern; 2 = species of the International Union for Conservation of Nature Red List (IUCN 2020) classified as Least Concern; 3 = species of the International Union for Conservation of Nature Red List (IUCN 2020) classified as vulnerable.