Biodiversity Data Journal :
Data Paper (Biosciences)
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Corresponding author: Víctor N. Velazco (velazcon951@gmail.com)
Academic editor: Arturo H. Ariño
Received: 21 Sep 2023 | Accepted: 04 Dec 2023 | Published: 18 Dec 2023
© 2023 Víctor Velazco, Rosana Sandler, Maria Cynthia Valeria Sanabria, Liliana Falco, Carlos Coviella, Leonardo Saravia
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Velazco VN, Sandler RV, Sanabria MCV, Falco LB, Coviella CE, Saravia LA (2023) Size spectra of the edaphic fauna of typical Argiudol soils of the Rolling Pampa Region, Argentina. Biodiversity Data Journal 11: e113074. https://doi.org/10.3897/BDJ.11.e113074
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Soil-dwelling organisms populate the spaces—referred to as interstices—between the litter on the soil surface and the pores in the soil's organo-mineral matrix. These organisms have pivotal roles in soil ecosystem functions, such as the breakdown and decomposition of organic matter, the dispersal of bacterial and fungal spores and biological habitat transformation. These functions, in turn, contribute to broader ecosystem services like carbon and nutrient cycling, soil organic matter regulation and both chemical and physical soil fertility.
This study provides morphological data pertaining to a range of soil organism sizes, specifically in Argiudol soils subjected to varying levels of agricultural activity in the Rolling Pampas Region, one of the world's most extensive and fertile plains.
The primary focus is on soil microarthropods—namely, Acari (mites) and Collembola (springtails)—with a body width of less than 2 mm. These organisms constitute the majority of life in the intricate soil pore network. Additionally, the study documents species of earthworms (Oligochaeta, Crassiclitelata), recognised as ecosystem engineers for their ability to create physical channels in the soil matrix and to distribute organic matter. Moreover, the study includes measurements of morphological traits of soil-dwelling "macrofauna" (organisms with a body width greater than 2 mm), which are also implicated in various soil ecosystem functions. These include population regulation by apex predators, organic matter decomposition, biogenic structure formation, nutrient mobilisation and herbivory.
In this paper, we report both the geographical locations and individual measurements of key morphological traits for over 7,000 specimens, covering a range of soil-dwelling organisms. These include springtails (Entognatha, Collembola), mites (Arachnida, Acari), earthworms (Oligochaeta, Crassiclitellata) and additional soil macrofauna. All specimens were collected from typical Argiudol soils located in three distinct agricultural systems characterised by varying levels of land-use intensity. To our knowledge, no other dataset exists providing this information for the Argentinian Pampas.
Soil fauna, soil invertebrates, Acari, Collembola, earthworms, body mass, body length, body width, Rolling Pampas, morphological traits, intensities of land use, occurrence, specimen
Soil-dwelling organisms are commonly classified by body size, using body width as the distinguishing morphological trait (
Within the mesofauna, mites (Arachnida, Acari) and springtails (Entognatha, Collembola) are the most abundant and diverse edaphic microarthropods, although, due to their body weights, they do not represent an important component of total edaphic metabolism (
Earthworms (Oligochaeta, Crassiclitellata) stand out within the macrofauna, since their presence contributes to the formation and maintenance of the physical structure of the soil, promoting aeration and permeability, which in turn provides optimal conditions for plant growth and the circulation of air, water and nutrients in the soil. In addition, due to their feeding mechanism, earthworms take the organic matter that accumulates in the soil, engulf it and deposit it as faecal pellets that are colonised by microorganisms, thus contributing to the humification processes and the release of nutrients (
The macrofauna does not present a high taxa diversity, but it does encompass a wide range of taxonomic ranks, differing at the level of orders and it plays a large number of functions in the edaphic ecosystem, such as herbivory, litter fractionation, control of populations by predators, transport of phoretic organisms and propagules of microorganisms and the formation of pores and habitats in the soil (
The taxonomic identification of the species that make up the community that inhabits the intricate network of pores and interstices of the soil is complex and, due to the great taxonomic diversity, its taxonomy is in constant revision and, furthermore, this identification becomes more difficult as the body size of the organisms decrease (
All organisms respond to environmental pressures with individual changes in morphological, physiological, phenological or behavioural traits. The pressures that modify the characteristics of the environment are also reflected as changes in the population structure of the taxa under study (
Considering the above, the understanding of cryptic soil communities at the local level becomes necessary and it can be addressed through the use of individual traits without considering their identification to the species level. This would make it possible to understand the processes that occur in ecological communities and improve the analysis capacity of cryptic communities (
The edaphic fauna is sensitive to the disturbances that occur to the soil, because human activities alter the habitat and the source of the resources that these organisms use (
Variations in body size in ecological communities due to changes in the environment are analysed using the size spectrum (
As described above, the changes in the size spectrum and in the biomass are linked to the response of the community to environmental pressures (
In this work, we present the dataset from GBIF data of
Soil Biodiversity 2023: Size Spectra of the edaphic fauna of Argiudol soils typical of the Rolling Pampa Region, Argentina.
The project focuses on the characterisation of edaphic fauna on Argiudol soils of the Rolling Pampas, one of the most fertile and extensive agricultural plains in the world, under three intensities of human impact. By measuring the individuals found over a two year sampling period and calculating their biomass, we strive to estimate energy flux through different parts of the edaphic fauna and to estimate community stability. In this work, we present the complete dataset collected for the project. To the best of our knowledge, there is no other dataset for the Rolling Pampas that shows the spectrum of sizes and biomass of edaphic fauna for the different taxa found.
In this document, we present the list of taxa of springtails (Entognatha, Colembolla), mites (Aracnida, Acari), earthworms (Oligochaeta, Crassiclitellata) and other macrofauna that occur in typical Argiudol soils under three systems with different anthropogenic impact, located in the Argentinian Rolling Pampas Region. This list has individual measurements of the main morphological traits of each of the mentioned taxa, such as measurements of body length, body width and estimated body weight for each organism.
Victor Nicolás Velazco, Rosana V Sandler, Cynthia Sanabria, Carlos E Coviella, Lilliana B Falco, Leonardo A Saravia, Gabriel Tolosa, Anabela Plos
Samples were collected from fields located in the districts of Chivilcoy and Navarro in the Province of Buenos Aires, Argentina. The sampling sites were fields with three different intensities of land use: 1) Naturalised grasslands (N): abandoned grasslands without significant direct anthropogenic influence for at least 50 years, whose predominant vegetation is Festuca pratensis, Stipa sp., Cirsium vulgare and Solanum laucophylumm; 2) Mixed livestock system (G): fields under continuous grazing with high animal load for 25 years, with a change towards forage production (bales of oats, corn and sorghum) for fattening two years prior to starting the study and 3) Agricultural system (A): fields under continuous intensive agriculture for 50 years and under no-tillage for the 18 years prior to the start of samplings.
For each land use system, three different sites in separate fields were selected as replicates. In each replica, three sampling points were randomly located and then georeferenced to return to the same site on each sampling date.
This project has been partially funded by a Doctoral Scholarship to Víctor Nicolás Velazco from the Concejo Nacional de Investigaciones Científicas (CONICET-Argentina), by the research programme in Terrestrial Ecology of the Universidad Nacional de Luján, with the support of the Instituto de Ecología y Desarrollo Sustentable (INEDES-UNLu-CONICET) and by Universidad Nacional de Lujan. There is also logistical support from the GBIF Argentina node, which is in charge of standards control, review and hosting of data and metadata.
The samples were taken from fields located in the districts of Chivilcoy and Navarro in Buenos Aires Province, Argentina.
The sampling sites were fields with three different intensities of land use: 1) Naturalised grasslands (N): abandoned grasslands without significant direct anthropic influence for at least 50 years, whose predominant vegetation is Festuca pratensis, Stipa sp., Cirsium vulgare and Solanum laucophylumm; 2) Mixed livestock system (G): fields under continuous grazing with high animal load for 25 years, with a change towards forage production (bales of oats, corn and sorghum) two years prior to starting the study and 3) Agricultural system (A): fields under continuous intensive agriculture for 50 years and under no-tillage for the 18 years prior to the start of the samplings.
The samplings were carried out once a season for 2 years. Soil subsamples with cores of 5 cm in diameter and 10 cm deep were taken at each sampling point. In order to obtain only the organisms living within the soil, the surface layer was gently brushed away before the soil samples were taken. Subsequently, the sample was homogenised and taken to the laboratory for the extraction of edaphic microarthropods using the flotation technique. In addition, at each sampling point, a 25 x 25 x 25 cm monolith was taken for the manual extraction of earthworms and other macrofauna organisms. The collected organisms were stored in 70% alcohol until their identification under a binocular microscope (
The edaphic microarthropods were extracted using the flotation technique, for which the homogenised sample was disaggregated and placed under water flow so that they pass through sieves with a 4 mm and 2 mm mesh opening, the soil that passed through the meshes was mixed in 2:1 ratio with a 1.2% magnesium sulphate solution.
The solution is allowed to settle for a few minutes until the mineral fraction of the soil settles and the supernatant in which the arthropods float is collected with a 98 um diameter sieve and stored in 70% alcohol until observation.
The collected supernatant was observed using a Leica S8P0 binocular microscope and, with the help of fine brushes and thin needles, the microarthropods were extracted and stored in 70% alcohol until their identification.
The identification of mites, springtails and worms and other fauna was carried out using taxonomic keys. After the identification, the body weights of the edaphic organisms were estimated, all of them expressed in micrograms of dry weight. The earthworms, after their identification, were weighed to determine the fresh weight, then they were dried under vacuum at 60 ºC and the dry weight factor of 0.15 on average was obtained (
The other organisms were measured one by one through photographs taken with a Leica S8P0 microscope with a built-in digital camera and whose rasters include a measurement scale depending on the configuration of the optical system at the time of capture.
Once the images were obtained, the ImageJ tool was used and the measurements of the body length and width of each of the individuals in micrometres were obtained.
Following this, several published linear equations relating body length and width were used to estimate the body weight of the organisms.
The length-width equations are general, but vary by taxonomic (
The Argentine pampa is a wide plain with more than 54 million hectares. Phytogeographically, it is located in the Neotropical Region, Chaqueño domain, Eastern district of the Pampean province and, therefore, the dominant vegetation is the steppe or pseudo-steppe of grasses (
The fields (Table
Geographical location of the fields in which the samples were taken. Coordinates are in WGS84 sexagesimal degree systems.
System Use | Site field | Latitude / Longitude |
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Agricultural System | Casuarina |
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Molino |
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Manga |
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Livestock System | L24 |
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L25 |
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L27 |
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Grassland | Romina |
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Festuca |
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Triángulo |
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-35.14 and -34.82 Latitude; -60.22 and -59.17 Longitude.
The edaphic fauna organisms were classified into different taxonomic categories (Table
Phylum | Class | Order | Family | Scientific Name | Taxon Rank |
Mollusca | Gastropoda | Gastropoda | Gastropoda (Cuvier, 1795) | Order | |
Arthropoda | Symphyla | Symphyla (Ryder, 1880) | Class | ||
Pauropoda | Parasitoidea (Oudemans, 1901) | Class | |||
Malacostraca | Isopoda | Oniscidea (Latreille, 1802) | Suborder | ||
Insecta | Psocoptera | Psocoptera (Shipley, 1904) | Order | ||
Orthoptera | Gryllotalpidae | Gryllotalpidae (Leach, 1815) | Family | ||
Gryllidae | Gryllidae (Laicharting, 1781) | Family | |||
Hymenoptera | Formicidae | Formicidae (Latreille, 1809) | Family | ||
Diptera | Sciaridae | Sciaridae (Billberg, 1820) | Family | ||
Cecidomyiidae | Cecidomyiidae (Newman, 1835) | Family | |||
Coleoptera | Scarabaeidae | Scarabaeidae (Latreille, 1802) | Family | ||
Ptiliidae | Ptiliidae (Erichson, 1845) | Family | |||
Carabidae | Carabidae (Latreille 1802) | Family | |||
Staphylinidae (Latreille, 1802) | Superfamily | ||||
Blattodea | Isoptera (Brullé, 1832) | Infraorder | |||
Entognatha | Symphypleona | Symphypleona (Börner, 1901) | Order | ||
Poduromorpha | Onychiuridae | Onychiuridae (Lubbock, 1867) | Family | ||
Hypogastruroidea (Börner, 1906) | Superfamily | ||||
Entomobryomorpha | Isotomidae | Isotomidae (Schäffer, 1896) | Family | ||
Entomobryoidea (Schäffer, 1896) | Superfamily | ||||
Chilopoda | Chilopoda (Latreille, 1817) | Class | |||
Arachnida | Trombidiformes | Tydeoidea (Kramer, 1877) | Superfamily | ||
Trombidioidea (Leach, 1815) | Superfamily | ||||
Eupodoidea (Koch, 1842) | Superfamily | ||||
Bdelloidea (Hudson, 1884) | Superfamily | ||||
Oribatida | Oripodoidea (Jacot, 1925) | Superfamily | |||
Oribatida (van der Hammen, 1968) | Subclase | ||||
Oppioidea (Grandjean, 1951) | Superfamily | ||||
Galumnoidea (Jacot, 1925) | Superfamily | ||||
Euphthiracaroidea (Jacot, 1930) | Superfamily | ||||
Epilohmannioidea (Oudemans, 1923) | Superfamily | ||||
Crotonioidea (Thorell, 1876) | Superfamily | ||||
Ceratozetoidea (Jacot, 1925) | Superfamily | ||||
Brachychthonioidea (Thor, 1934) | Superfamily | ||||
Mesostigmata | Veigaioidea (Oudemans, 1939) | Superfamily | |||
Uropodoidea (Kramer, 1881) | Superfamily | ||||
Rhodacaroidea (Oudemans, 1902) | Superfamily | ||||
Parasitoidea (Oudemans, 1901) | Superfamily | ||||
Mesostigmata (G. Canestrini, 1891) | Order | ||||
Dermanyssoidea (Kolenati, 1859) | Superfamily | ||||
Astigmata | Acaroidea (Latreille, 1802) | Superfamily | |||
Araneae | Linyphiidae | Linyphiidae (Blackwall, 1859) | Family | ||
Annelida | Clitellata | Crassiclitellata | Lumbricidae | Octolasion lacteum (Örley, 1881) | Species |
Octalacyum cyaneum (Savigny, 1826) | Species | ||||
Acanthodrilidae | Microscolex phosphoreus (Duges, 1837) | Species | |||
Microscolex dubius (Fletcher, 1887) | Species | ||||
Ocnerodrilidae | Eukerria stagnalis (Kinberg, 1867) | Species | |||
Lumbricidae | Apodorrectodea trapezoides (Duges, 1828) | Species | |||
Apodorrectodea rosea (Savigny, 1826) | Species | ||||
Apodorrectodea caliginosa (Savigny, 1826) | Species | ||||
Crassiclitellata (Jamieson, 1988) | Order |
The mites were identified up to superfamilies (
All the organisms of the edaphic fauna extracted by the sifting and flotation technique (
The organisms were taxonomically identified and then these organisms were characterised by their morphometric features. The morphometric traits measured were body length and body width, which allow the estimation of the body weight of each organism through the use of previously documented linear regression equations (
Photographs of each member of the edaphic biota (see Fig.
Graphic summary of the steps followed to obtain the measurements of the morphological traits, that is, the length and width of the body. Step one: upload the images to ImageJ. Step two: Configure the measurement tool through the relationship of the measurement scale and the length of pixels that it represents. Step three: take measurements of the lengths of interest.
To obtain the length measurements of the body length and width, each image was processed using the ImageJ software (
Body weight estimates were made by using morphometric linear equations (Table
Regression length-mass relationships with reference to the authors who estimated the regression equations and the body shape to which the different taxa fit. L = length of the body; l = width of the body; W = body weight; Log = base ten logarithm; ln = natural logarithm. The dry weight factor is inidicated only when neccesary for estimating dry weight.
Author | Body plan morphotype | Length-mass relationship equations | dry weight factor |
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Hipogastruridae | log W = 2,55 * log L + 0,99 | |
Isotomidae | log W = 2,78 * log L + 0,71 | ||
Onychiuridae | log W = 2,75 * log L + 0,63 | ||
Entomobriidae | log W = 2,5 * log L + 0,83 | ||
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Symphypleona | log W = log 39,6278 + 0,83 * log L | |
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Trombidiformes | W = (0,00387 * L) 3 | 0.4 |
Mesostigmata | W = 0,85 * (L 2,09 * l 0,84 * 10 -6,44) | 0.4 | |
Symphyla and Pauropoda | W=(1,20 + L) 3 | 0.2 | |
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Achipteriforme oribatid’s | log W = 2,09 log L + 0,93 log l – 6,67 | 0.4 |
Nothriforme oribatid’s | log W = 2,09 log L + 0,84 log l – 6,44 | 0.4 | |
Carabodiforme oribatid’s | log W = 1,62 log L + 1,40 log l – 6,56 | 0.4 | |
Acari | log W = 1,53 log L + 1,53 log l – 6,67 | 0.4 | |
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Gastropoda | W = 0,172 L1,688 | |
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Arannae | In W = - 3.2105 + L * 2.4681 | |
Coleoptera adult | In W = - 3.2689 + L * 2.4625 | ||
Coleoptera larvae | In W = - 7,1392 + L * 0,8095 | ||
Diptera | In W = -3,4294 + L * 2,5943 | ||
Formicidae | In W = - 3,1415 + L * 2,3447 | ||
Insecta | In W = - 3,0710 + L* 2,2968 | ||
Isopoda | W = - 1,1167 + L * 0,4762 | ||
Pauropoda and Collembola | In W = - 1,8749 + L* 2,3002 | ||
Chilopoda | In W = - 6,7041 + L * 2,8420 | ||
Orthoptera | In W = - 3,5338 + L * 2,4619 | ||
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Diplopoda Myriapoda | ln W = 2,38 * ln (L) – 2,77 | 0.45 |
Density distribution of body weight in micrograms of dry weight of the taxa that make up the edaphic fauna community in the different land-use systems. Horizontal axis: body weight in micrograms on a logarithmic scale. Vertical axis: taxa by their scientific name. Legend: the colours refer to the phylum to which the different taxa belong.
The dataset is then left with values of the following morphological traits: the body length and width in micrometres of the edaphic fauna, with the exception of earthworms and the body weight in micrograms of dry weight of each organism of the edaphic fauna found in the different sampling events.
The sampling design covered seasonal variability with bimonthly sampling over two years.
These datasets present the invertebrates of the edaphic fauna whose specimens belong to different taxa of Collembola, Entognatha (springtiails), Acari, Arachnida (mites), Crassiclitellata, Oligochaeta (earthworms) and other invertebrates of the edaphic fauna (Mollusca and Arthropoda) that are part of the macrofauna.
Each row records the presence of soil organisms and these were validated according to the Darwin Core Standard (DWC).
These soils are found in the Rolling Pampas Region, Argentina, one of the most extensive and fertile plains in the world. The data geographically references the sampling sites and also includes the date on which the samplings were taken.
Column label | Column description |
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occurrenceID | An unique identifier for the occurrence event. |
institutionCode | The name in use by the institution. |
collectionCode | The code identifying the collection. |
catalogNumber | A unique identifier for the record within the dataset. |
basisOfRecord | The specific nature of the data record: "Occurrence". |
type | The nature or genre of the resource: "PhysicalObject". |
datasetName | The name identifying the dataset. |
habitat | A category for the habitat. |
day | The integer day of the month on which the event occurred. |
eventTime | The interval during which an event occurred. |
otherCatalogNumbers | A list (concatenated and separated) of previous catalogue numbers. |
higherGeography | A list (concatenated and separated) of geographic names less specific than the information captured in the country term. |
continent | The name of the continent in which the event occurs. |
country | The name of the country. |
countryCode | The standard code for the country. |
stateProvince | The name of the next smaller administrative region than country (province) in which the registry occurs. |
county | The name of the smaller administrative region. |
month | The integer month in which the event occurred. |
year | The four-digit year in which the event occurred. |
kingdom | The full scientific name of the kingdom in which the taxon is classified. |
phylum | The full scientific name of the phylum in which the taxon is classified. |
class | The full scientific name of the class in which the taxon is classified. |
order | The full scientific name of the order in which the taxon is classified. |
family | The scientific name of the family in which the taxon is classified. |
genus | The genus part of the scientific name without authorship. |
specificEpithet | The name of species epithet of the scientific name. |
higherClassification | A list (concatenated and separated) of taxon names terminating at the rank immediately superior to the referenced taxon. |
scientificName | The full scientific name or lowest level taxonomic rank that can be determined, with authorship and date information. |
taxonRank | The taxonomic rank of the most specific name in the scientificName. |
verbatimLatitude | The verbatim original latitude of the occurrence Location. |
verbatimLongitude | The verbatim original longitude of the occurrence Location. |
decimalLatitude | The geographic latitude, in decimal degrees. |
decimalLongitude | The geographic longitude, in decimal degrees. |
verbatimSRS | The ellipsoid, geodetic datum or spatial reference system (SRS), upon which coordinates given in verbatimLatitude and verbatimLongitude are based. |
georeferencedBy | Names of people, who determined the georeference for the location occurrence. |
recordedBy | Reference to the method used to determine the spatial coordinate names of people responsible for recording the original occurrence. |
recordedByID | Globally unique identifier for the person responsible for recording the original occurrence. |
samplingProtocol | Descriptions of the methods used during the event sampling. |
sampleSizeValue | A numeric value for the size of a sample in a sampling event. |
samplingEffort | The unit of measurement of the size of a sample in a sampling event. The amount of effort when sampling a event. |
verbatimCoordinateSystem | The coordinate format for the verbatimLatitude and verbatimLongitude. |
occurrenceRemarks | Notes about the occurrence. |
eventDate | The date-time during which an event occurred. |
sampleSizeUnit | The unit of measurement of the sample size of the sampling event. |
georeferenceProtocol | A link to the reference on the methods used to determine the coordinates. |
These datasets present the invertebrates of the edaphic fauna whose specimens belong to different taxa of Collembola, Entognatha (springtiails), Acari, Arachnida (mites), Crassiclitellata, Oligochaeta (earthworms) and other invertebrates of the edaphic fauna (Mollusca and Arthropoda) that are part of the macrofauna.
Each row records individual measurements of morphological traits of soil organisms that are extensions of the occurrence dataset described above and validated according to the Darwin Core Standard (DWC).
Column label | Column description |
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occurrenceID | A unique identifier taken from the occurrence dataset and linking it to the measurements of each occurrence. |
measurementValue | The value of the measurement. |
measurementUnit | The units associated with the measurementValue. |
measurementType | The nature of the measurement. |
measurementMethod | A description of the method used to determine the measurement. |
measurementDeterminedBy | Names of people who determined the value of the measurement. |
measurementDeterminedDate | Date range on which the measurement was taken. |
measurementAccuracy | The description of the estimated error associated with the measurementValue. |
The authors acknowledge the valuable help of Dr. Anabela Plos (GBIF node Argentina, Ministerio de Ciencia y Tecnica, Argentina) with the structure of the database and metadata revision, to upload the work to the IPT server and GBIF registration. This project was partially funded by a PhD student fellowship to Velazco by CONICET (Argentina), by INEDES (UNLu-CONICET) and by Universidad Nacional de Lujan.
The authors also wish to thank Dr. Ann Marie Soderini, University of Minnesota for her help in the revision of the English language of this manuscript.
Nicolas Velazco: updated the ID of the specimens, photographed and measured all the 8662 individuals collected, built the database and collaborated with the writing of the manuscript. Rosana Sandler: Did all the fieldwork, collected and separated the specimens and did the first ID of the specimens. Cynthia Sanabria: database construction, and collaborated with the writing the manuscript. Carlos Coviella: project design, project development, and collaborated with the writing and revising of the manuscript. Liliana Falco: project design, project development, statistical analyses and collaborated with the writing of the manuscript. Leonardo Saravia: Project leader, project design, statistical analyses, collaborated with the writing of the manuscript.