Geographic review on the specimens of the Caatinga Biome in the Jardim Botânico do Rio de Janeiro (RB) herbarium

Abstract

Introduction

The Caatinga phytogeographic domain is South America’s largest and most biodiverse tropical semi-arid ecoregion (Moro et al. 2016). It occupies interplanaltic depression areas northeast and northwards of Minas Gerais state in Brazil (Ab’Saber 2007) and is distributed along an estimated area of 844,000 km². Originally, the biome represented 11% of the Brazilian territory (Ministério do Meio Ambiente 2018). Although the diversity of plants and animals may be considered low when compared with other regions (e.g. tropical forests), the biological patrimony in this region is adapted to the local extreme conditions, resulting in high endemism rates (Queiroz et al. 2017).

Caatinga encompasses woody vegetation that is thorny and deciduous (Ab’Saber 1974) and can be divided into 12 types according to abiotic variations of altitude, continentality and soil features (Alves et al. 2008, Araújo et al. 2005). This biome is facing continuous deforestation processes related to wood extraction, farming and agriculture (Ribeiro et al. 2015, Marinho et al. 2016), which generates negative effects on biodiversity, such as habitat loss and fragmentation (Antongiovanni et al. 2018) and desertification (Hauff 2010).

Conservation Units are defined as territorial spaces protected by public or private initiatives in order to promote biodiversity conservation, restoration and management, as well as to protect natural resources while encompassing extractivism and sustainable uses. In Brazil, the National System of Conservation Units (Brasil 2011) separates Conservation Units into two conservation groups and some categories of preservation. The Full Protection Units group targets nature preservation in a restrictive way, accepting only indirect use of its natural resources. On the other hand, the Sustainable Use Units aim to reconcile nature conservation and sustainable uses.

Less than 5% of Caatinga’s territory is currently covered by Conservation Units (CU) (Oliveira et al. 2013), whereas 30% of its typical biodiversity occurs entirely outside of protected areas, which promotes gaps in the protection, research and management of flora species (Fonseca and Venticinque 2018). It is estimated that at least 4,843 species of plants have been registered for this region (BFG 2018), with 1,523 cases of endemism (Flora do Brasil 2020 2019)

Although the importance and conservation of Caatinga’s biodiversity is well recognised, new gatherings of flora specimens are scarce (Correia et al. 2019, Moro et al. 2016). In this regard, for collected samples, a specimens’ inventory is essential for subsidising systematic analyses that are capable of promoting scientific research projects, public policies and guiding authorities’ decisions about its management and restoration (Silva et al. 2017).

The RB Herbarium of Jardim Botânico of Rio de Janeiro (JBRJ), created in 1890, is composed of seven botanical collections: mounted specimens (RB – 750,000, with 7,500 nomenclatural types and ~3,000 paratypes), wood (RBw - ca. 10,300 specimens), fruits (RBcarpo - ca. 8,000 specimens), DNA bank (RBdna - ca. 5,700 specimens), spirit (RBspirit - ca. 2,500 specimens), seedbank (RBsem - ca. 2,700 specimens) and ethnobotany (RBetno – ca. 200 specimens) (Forzza et al. 2016, Lanna et al. 2018). Data used in the present work were acquired in the RB Herbarium collections and exhibit a historical series encompassing approximately 130 years (Fig. ​(Fig.1A),1A), distributed throughout eight states (Fig. ​(Fig.11B).

Open in a separate window

https://binary.pensoft.net/fig/295449

Figure 1.

Number of Caatinga’s species deposited in the RB Herbarium. A. Number of species deposited per year; B. Number of species deposited per State.

Our goal is to gauge the amount of collections performed in Federal Conservation Units that belong to the Caatinga domain through the correction and recovery of geographic coordinates of flora samples present in the RB Herbarium. The objective is to make the material available in the Jardim Botânico Botanical Collections Management System (Jabot) (Silva et al. 2017) to assist historical series research development (Kamino et al. 2011), predictive modelling for species distributions and to support conservation status assessments.

Sampling methods

Study extent

The Caatinga biome has 25 Federal Conservation Units that total 31,952 km², which represents 5% of its territory and encompasses the states of Alagoas, Bahia, Ceará, Maranhão, Pernambuco, Paraíba, Rio Grande do Norte, Piauí, Sergipe and the north of Minas Gerais (Brasil 2018). Despite the long collection of historical data (Fig. ​(Fig.1),1), scarce samples are still in the states of Maranhão and north of Minas Gerais (Fig. ​(Fig.2).2). One of the main reasons for such scarcity is that these states are territories of transition between the Cerrado and the Caatinga biomes, in which Conservation Units are commonly categorised as belonging to the Cerrado biome. The study area, the Conservation Units spatial distribution and samples of pre- and post-geographic coordinates correction are presented in Fig. ​Fig.22.

Open in a separate window

https://binary.pensoft.net/fig/339045

Figure 2.

A. Study area; B. Spatial distribution of Brazilian Conservation Units according to the Brazilian Ministry of the Environment; C. Samples’ distribution before geographic coordinates correction; D. Samples’ distribution after geographic correction. Maps were prepared using ArcGIS.

Geographic coverage

Collection data

Usage rights

Data resources

Acknowledgements

References