The flora of south-eastern Mato Grosso State (Brazil): a review of herbarium collections

Abstract The diversity and richness of the Brazilian flora are documented in herbarium collections. When areas are deforested, but not documented, we lose both flora and the opportunity to know which species occupied those areas. The south-eastern mesoregion of Mato Grosso State, comprising 22 municipalities, has undergone the loss of native vegetation cover, accelerated by the substantial expansion of agribusiness. For an in-depth look at the consequences and the current state of the flora in that mesoregion, we consulted both speciesLink and JABOT databases. More specifically, we carried out a comprehensive study of herbarium collections by municipality and compiled data including scientific name, collection date, collection locality, collector name and observations made during collection. We obtained 5,861 records of angiosperms, ferns and lycophytes of 160 families, 770 genera and 1,792 species. The specimens are deposited in 80 herbaria of which the Herbarium of Universidade Federal de Mato Grosso (UFMT) hosts the largest collection. Rondonópolis was the most sampled municipality, whereas 50% of the municipalities were poorly sampled and one showed no collection records at all. Amongst the species occurring only in Mato Grosso, eleven were collected only in that mesoregion and twenty species were under some degree of threat. Our study recommends increasing collection and identification efforts to enable effective conservation actions and improve richness estimates for the State of Mato Grosso and the Cerrado, in general, before more of the flora is lost to deforestation.


Introduction
Brazil is recognised as one of the richest countries in plant diversity. The Brazilian Flora has recorded the occurrence of approximately 38,676 species of vascular plants and bryophytes of which Angiosperms correspond to over 90% of the total (Flora do Brasil 2020). Available data also show that approximately 57.4% of Angiosperm species are endemic to the country (BGF -The Brazil Flora Group 2015).
Specimens records are documents that certify flora diversity and richness of a given region or country and are deposited in botanical collections. These collections exist of living or herbarium material and their associated data (Peixoto and Morim 2003).
According to Willis et al. (2003), botanical collection data are often the only available data for a given species and qualify as a fundamental tool for assessing the conservation status of a species. The analysis of the information contained in the exsiccatae labels, encompassing geographical and ecological aspects, can support several studies. Any biodiversity or systematic study largely depends on the quality and representation of herbarium collections (Shepherd 2003). One of the main purposes of herbarium collections is to serve as taxonomic repositories: storing specimens allows users to return to them over decades and centuries to check the identification of plants and study the characteristics of the given species, reference collections used to identify species and describe new species (Greve et al. 2016).
Besides documenting the country's biological diversity, the specimens deposited in herbaria keep part of the history of regions previously covered by natural vegetation, which are now occupied by cities, various enterprises or which are now deforested (Peixoto et al. 2009).
Without the existence of voucher materials in herbaria, it is impossible to verify whether observations are correctly identified, to assess the geographic distribution, carry out species distribution modelling analysis, study the phylogeny or even define the conservation status of a species (Windisch and Peralta 2010) and priority areas for conservation using floristic criteria. Furthermore, botanical knowledge is essential for vegetation, ecology and conservation studies (Pott and Pott 1999).
According to MacDougall et al. (1998), herbaria data provide two types of information especially relevant to conservation planning: location of species occurrence, which indicates where they were found and may persist and habitat descriptions for each species. To preserve such information, the herbarium is a valuable resource, capable of storing comprehensive data of individual plants and representatives of species, as well as natural or cultivated populations. Thus, at its foundation, the most obvious function performed by herbaria is that of documenting botanical studies, especially taxonomic and floristic ones (Monteiro and Siani 2009 The south-eastern mesoregion of Mato Grosso is composed of 22 municipalities (Miranda and Bastos 2016). It is an area with a strong presence of farming and cattle breeding (Borges et al. 2014). Areas with remnant natural vegetation are fragmented, generally located in difficult to access sites and rugged relief that are hard to transform into pastures or crops.
Owing to the rapid loss of native vegetation cover and the scarcity of studies (SEMA -Secretaria de Estado de Meio Ambiente 2021), it is essential to assess the current state of knowledge of the region's vegetation to support and guide actions for the recovery and conservation of the local flora.
Thus, the following questions guided our study: 1.
How are family, genus and species diversity represented in the south-eastern mesoregion of the State of Mato Grosso? 2.
What is the frequency of occurrence records? 3.
Where are the collections spatially concentrated? 4.
Does the data collection of specimens sampled in south-eastern Mato Grosso enable defining the poorly-sampled areas that still hinder the study of local flora? 5.
Are any endangered or extinct species found in the region?
The soils of the south-eastern mesoregion vary between Dark-Red and Red-Yellow Latosols, Red-Yellow Podzolic, Cambisols and Quartz Sands (SEPLAN -Secretaria de Estado e Planejamento e Gestão 2019).

Data collection
The databases from speciesLink (http://inct.splink.org.br) and JABOT (Botanical collections management system of the Rio de Janeiro Botanical Garden -JBRJ) (http://jabot.jbrj. gov.br) networks, with records up to December 2019, were consulted. Data from the Global Biodiversity Information Facility (GBIF) (GBIF Secretariat 2019) network for herbaria abroad that were integrated into the speciesLink network were also used.
For each of the 22 municipalities studied, we surveyed the herbaria containing records and compiled information from these records, including family, scientific name, collection date, collection locality, collector name, geographic coordinates and observations made during collection. Indigenous lands located within these municipalities were also assessed. We created a spreadheet in EXCEL (version 2016) to facilitate information organisation, checking and editing duplicate records; 186 records were discarded, which included only the name of the state, but no information about the municipality or location that could support the inclusion of the sample in one of the municipalities in the south-eastern mesoregion of Mato Grosso. We also excluded 269 records containing no date and followed the same procedure for samples without specific determination. We used ESRI ARCGIS, v.10.5 and ARCVIEW GIS 3.2 software to prepare maps.
Herbaria with fifty or more records of the studied area were considered significant (Table 1). We considered 200 collections or more as significant for the municipality. Families were listed following APG IV (APG 2016). Scientific names were checked and updated following the Flora do Brasil 2020 (http://floradobrasil.jbrj.gov.br) and, whenever necessary, specialists for the specific group were consulted, as in the case of Chaetothylax

Taxonomic diversity
The inventory showed a total of 5,861 records of angiosperms, ferns and lycophytes distributed amongst 160 families, 770 genera and 1,792 species and infraspecific categories (Suppl. material 1). Of the total number of records, 5.59% were identified up to the family and 17.64% up to the genus, the remaining specimens being identified up to species level.
The ten families with the highest number of occurrence records and the highest richness were those already recorded in other studies in Cerrado areas (Ratter 1997, Mendonça et al. 2008,Campos et al. 2018. Fabaceae remained the most collected family and showed the highest species richness. Euphorbiaceae was the second most recorded family and the fourth in number of species, while Poaceae was the second in richness, despite being the third most collected family (Fig. 2). The percentage of families represented by a single species was 26.9% or 43 families.  (17). Our data also showed that 57.8% of species were collected only a single time, revealing the need for a significant increase in fieldwork to collect and identify the material deposited in collections.
It is worth highlighting that the species with the highest number of collections, H. brasiliensis (rubber tree), is mainly native to the states of northern Brazil with no natural occurrence in Mato Grosso (Flora do Brasil 2020). It is considered a cultivated species in the region and, in the present study, all specimens came from a rubber tree plantation in the District of Ouro Branco, Municipality of Itiquira. The other species mentioned are widely distributed in the Cerrado in several states, except for Rauvolfia weddeliana (Apocynaceae), the occurrence of which is confirmed only in the States of Mato Grosso and Mato Grosso do Sul (Flora do Brasil 2020).

Herbarium collections
The records of flora species from the south-eastern mesoregion of Mato Grosso are deposited in eighty herbaria in Brazil and abroad. The Herbarium of the Federal University of Mato Grosso (UFMT) contains the largest collection (744 records), both in number of records and species diversity of the studied area. The second-largest collection is housed in the Municipal Botanical Museum of Curitiba (MBM) (495 records) and the third is in the Herbarium of the University of Brasília (UB) (395 records) (Fig. 3).
The botanist Gerdt G. Hatschbach, founder of the MBM, was the primary collector in Brazil, as well as amongst the most prominent in the number of collections. His records in the region cover the period between 1966 and 1998.

Collection periodicity
The oldest collection record in the region is a fern species with wide distribution in the country, Didymoglossum punctatum (Poir.) Desv.  between 1908between and 1915between (Sá et al. 2008. The aforementioned botanical collections made by Marshal Rondon seem to evidence his proximity to natural history. The Rondon Commission played an important role in the natural history of the State of Mato Grosso, which, at the time, occupied much more territory. According to Sá et al. (2008), the study of the botanical material collected during the project included the participation of several foreign specialists. At the time, were no specialists for most Herbaria with fifty or more records of specimens from the south-eastern mesoregion of Mato Grosso.
taxonomic groups collected in Brazil. Moreover, specialised literature and type material for comparison in Brazilian herbaria were largely absent. Hoehne, who was responsible for organizing the botanical specimens, was concerned about disseminating the results of such an important project and decided to send part of the material abroad to be studied by specialists (Sá et al. 2008). Unfortunately, the route of the Rondon Commission did not include the south-eastern region of the State of Mato Grosso which could explain the small number of records between 1900-1930.
The following decades saw a significant recovery in collections, which started in the 1960s, but peaked between 1990 and 1999. With the consolidation of undergraduate and graduate courses in several institutions, it is likely that academics from UFMT and researchers from Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA-Pantanal) went into the field to carry out their studies, resulting in an increase in records deposited in herbarium collections (Fig. 4).

Spatial characterisation of collections
The Municipality of São Pedro da Cipa was the only one with no collection. Rondonópolis, the largest municipality in the region, was sampled the most (1,116 collection records), followed by Alto Araguaia (956), which borders the state of Goiás and Itiquira (502), which borders the State of Mato Grosso do Sul. The three municipalities have a good highway network, providing easy access.
Considering a minimum number of 200 records per municipality, it was possible to evaluate a rather high percentage of municipalities (50%) having a poorly-collected area, i.e. less than 200 samples deposited in collections (Fig. 5). The Rondonópolis region is strategically located at the junction of highways BR-163 and BR-364, connecting the northern and southern regions of Brazil. Thus, the easy access, good infrastructure and the Biological Sciences course of the Federal University of Rondonópolis may have contributed to the higher number of records (Fig. 6).
Most collections in the south-eastern mesoregion of Mato Grosso occurred along roads, followed by those along watercourses. Protected areas represent 1.47% of the total records with 13 species collected exclusively in these areas ( Table 2). The present study showed poor floristic knowledge, reinforcing the need to intensify floristic sampling in these areas.
According to Barbosa and Vieira (2005), the northern and Midwest regions of Brazil have the lowest number of herbaria and the smallest set of specimens in collections, not reaching one sample/km . Therefore, these regions face major challenges. Although they represent an important part of the Brazilian territory, concentrating different natural ecosystems, they have the lowest collection rates and the lowest number of specialists and herbaria.
Municipalities of the south-eastern mesoregion of Mato Grosso represented in shades of grey according to the number of records. However, the number of records found in the present study (of 0.081 specimens/km ) is lower than those cited by either Barbosa and Vieira (2005) Figure 6.
Number of occurrence records of collections per municipality in the south-eastern mesoregion of Mato Grosso. Table 2.
Collections in protected areas in the south-eastern mesoregion of Mato Grosso.
The flora of south-eastern Mato Grosso State (Brazil): a review of herbarium ...

Endemic and endangered species
Of the 166 species mentioned in Flora do Brasil (2020), with confirmed occurrence only in Mato Grosso, 6.6% (11) were collected in the south-eastern region of the State and of these, three were collected exclusively in this region: Blepharodon hatschbachii Fontella & Marquete (Apocynaceae), Mikania sarcodes Baker (Asteraceae) and Onoseris brasiliensis Cabrera (Asteraceae). These results indicate low effort in collecting and identifying botanical material to check for the presence of other possible endemic species.
In addition, we found twenty species under some degree of threat (

Conclusions
The south-eastern mesoregion of Mato Grosso is composed of 22 municipalities and shows a remarkable species richness and diversity, as documented in herbarium collections. Therefore, we want to stress the importance of inventorying and characterising local flora species and their populations. The consulted herbarium collections contained 1,792 species of this region, with many undetermined collections. Unfortunately in this study, a large number of municipalities showed scarce records and locality information.
Therefore, we want to stress the importance of increasing the efforts to collect and identify species in the region to improve estimates of flora richness for the south-eastern mesoregion, the entire State of Mato Grosso and the phytogeographic domain of the Cerrado. The data we found indicate that poorly-collected municipalities, i.e. those with less than 200 plant samples recorded in herbarium collections, corresponded to 50% of the municipalities in the south-eastern mesoregion of Mato Grosso.
Poor knowledge of the vegetation of protected areas in the region still characterises herbaria collections in the region, making it difficult to assess the conservation status for endangered and endemic species. In fact, this difficulty is emphasised by the elevated proportion of species (~ 58%) with only one record observed for the south-eastern mesoregion of Mato Grosso. Studies with these taxa are needed to develop better conservation strategies.
The increase in floristc projects for this region, associated with the increase in qualified professionals in the area, is fundamental for conservation decision-making. In addition, the low collection rate, together with the high percentage of collections carried out by only a few collectors, demonstrates the urgency for increasing human resources to collect and identify plants.