Bryophyte collection of Porto Herbarium (PO)

Study Extent

The dataset includes Portuguese mainland species collected by hand. Sampling extending from 1873 to 1987 was done mainly by António Luís Machado Guimarães on northwest mainland Portugal. The two other collections were done in specific habitats (watercourses and exposed rock outcrops) during ecological surveys between 2002 and 2007 and the contributors are Cristiana Vieira and Helena Hespanhol, covering north and central Portugal.

Sampling

The historical bryophyte collection of António Machado was done by António Luís Machado Guimarães and other contemporary collectors. The sampling was done from 1873 to 1987, on occasional basis and next to collector’s areas of residence and sporadic visits during vacations as was typical of those times. Most of the material corresponded to the first specimens of many bryophytes collected for the northern Portuguese territories, but as far as is known, no particular sampling design was established for the collection of specimens in the several habitats. The watercourses collection was compiled under PhD work sampling design and in total, 178 river segments (defined as 100 m length of the riverbed and its margins) of 11 river basins, were studied from June 2002 to August 2005. These basins were chosen in order to survey mountain territories with different geomorphologic and climatic contexts, and subjected to different levels of human pressure. This survey was performed during the lowest water discharge levels (late Spring and Summer), to access the minimum water levels. The water depth in which populations were found corresponds, therefore, to the lowest level of submersion. Bryophytes were surveyed in all immerged or semi-immerged microhabitats found within the 100m of riverbed and margins. This study focused mostly in the rocky substrates, although we sporadically included micro-habitats that showed some deposition of silt or sand within the bryophyte patches. Bryophyte species abundance was registered as percentage cover using 0.25 m2 (0.5 m × 0.5 m) sample plots placed in all recognizable hydrologic zones: microhabitats constantly or easily immerged seasonally or several times a month with discharges related to precipitation or dam releases, and micro-habitats immerged only in extended periods of rain that might show some evidences of fine substrate. The exposed rock outcrops datasets was compiled under PhD work sampling design and in several mainland mountains. Fieldwork was carried out in 100 localities, distributed over 11 mountain areas from March 2005 and April 2007. Sample sites were selected according to the extent and altitudinal variation of the mountain. At each sampling site three types of microhabitats were explored (1) fissures, extending out horizontally or vertically, with a maximum width of 15 cm, with soil accumulation; (2) cavities, defined as a narrow horizontal opening with a roof and a floor, with a maximum height of 50 cm; and (3) rock surfaces, defined as continuous rocks without cracks, ranging from horizontal to almost vertical. Ten sample plots were recorded in the different microhabitat types identified at each sample site, within a maximum area of 100m2 in order to represent as well as possible the whole ecological and floristic variation within each sample site. The plots had an area of 625 cm2 and their shape was adapted for each microhabitat (25 cm × 25 cm for rock surfaces and 50 cm × 12.5 cm for fissures and cavities). In total, 201 sample plots were surveyed within cavities (granite: 180; schist: 21), 238 within fissures (granite: 165; schist: 73) and 455 on rock surfaces (granite: 360; schist: 95), at different exposures and slopes. Percentage cover was used to obtain an estimate of bryophyte species abundance on rock surfaces. Presence/absence of bryophyte taxa was registered on sample plots performed on fissures, cavities and rock pools.

Quality Control

Data cataloguing was originaly done using MS Access database. The insertion of most fields was done using controled vocabularies whenever possible. Taxa nomenclature follows Ros et al.(2013) for mosses and Ros et al.(2007) for liverworts. The historical bryophyte collection of António Machado was georreferenced using SCRIF (http://scrif.igeo.pt/)and google maps. Latitude and longitude of the other two collections (watercourses and exposed rock outcrops) were estimated using GPS.

Method steps

1. NA

All bryophytes were identified to the species, subspecies, variety or genus.

1. Plantae
   rank: kingdom
2. Anthocerotophyta
   rank: phylum
3. Marchantiophyta
   rank: phylum
4. Bryophyta
   rank: phylum

This dataset covers the whole country of Portugal (mainland), with 99.25% of the records georeferenced.