LeafQualityDatabase.xlsx

This data set comes from the research carried out by Sena et al. <em>Study sites</em> We studied riparian forests of low-order streams located inside preserved areas (1st-3rd order reaches; hereafter sites) in three South American biomes: (i) Amazon (2 sites), (ii) Cerrado (3 sites), and (iii) Atlantic Forest (6 sites). Sites in the Amazon were located in nonflooded forests in the central and northern Amazon with equatorial climate, tall trees, and evergreen canopy. Cerrado sites were located in the Brazilian Central Plateau with a tropical wet‒dry climate, where streams drain through dense corridors of evergreen forests known as gallery forests. Atlantic Forest sites were located in inland and coastal areas of Brazil, spanning a large latitudinal gradient in climate (~ 30 degrees of latitude), from subtropical to equatorial, comprising tropical and subtropical rainforests, Araucaria forests and seasonal tropical forests. The dataset analyzed comprises information from litter for 68 plant species collected across 11 riparian forests within preserved areas (reference conditions) of three neotropical biomes within the tropics: the Amazon (Cantá and Manaus), the Cerrado (Patrocínio, Brasília and Palmas) and the Atlantic Forest (Erechim, Florianópolis, Varzedo, Parnamirim, Palotina and Santa Leopoldina). We analyzed seven chemical traits (%C, %N, %P, %Phenols, C:N, C:P, and N:P ratios) and two physical traits of the litter (toughness and specific leaf area). <em>Field sampling protocol</em> The sampling sites consisted of a 100 m stretch of each forest stream with the most extensive vegetation cover and without apparent anthropogenic impact. Litterfall was sampled using suspended litter traps (1 m2, 10 mm mesh) fixed 1.5 m high on both streambanks to optimize the sampling effort. Fallen leaves were collected every 15 days to avoid leaching or decomposition. Recently fallen leaves were sampled during the period of maximum litterfall in the year, which was defined according to recent literature (Tonin et al., 2017) and/or the expertise of local researchers. Litter was transported to the laboratory and oven-dried (60 °C, 72 h) for chemical analyses; litter used to determine specific leaf area (SLA) and toughness was air-dried only. All litter samples from the same site were pooled and homogenized. Then, the litter for the 5-10 most representative tree species in terms of dry mass were separated and identified to the lowest possible taxonomic level. <em>Physical and chemical characterization of litter traits</em> Twenty grams of litter from each was ground in a vibratory ball mill (Fritsch Pulverisette, Model 0, Idar-Oberstein, Germany) for the chemical analyses. The C and N concentrations (% of dry mass) were analyzed by total combustion (950 °C) in an elemental analyzer (Leco Instruments Ltda, Model Truspec CHN628, San José, Michigan, USA). The P concentration was quantified spectrophotometrically (measuring absorbance at 882 nm) using the ascorbic acid method after combustion (550°C for 4 h) and digestion (with hydrochloric acid) of litter samples (Flindt et al., 2020). Total phenols were determined using the Folin-Ciocalteau method (Bärlocher &amp; Graça, 2020). All chemical analyses were run using triplicates of 100-mg portions of litter powder from each species. Entire leaves were used for the determination of SLA and toughness. SLA, a proxy for litter toughness (that is, higher SLA values are usually found for softer litter; Boyero et al., 2017), was estimated using 10-20 leaf discs (12 mm diameter) from different parts of the leaves and from different leaves of the same species. Each leaf disc was then weighed (0.01 mg) to determine its mass. SLA was obtained through the quotient of leaf disc area to leaf dry mass (in grams). Litter toughness was estimated with a penetrometer, which measures the pressure (in kgF cm-1) necessary to pierce the tissue of a leaf with a steel rod (1.55-mm diameter) (Boyero et al. 2011). The litter toughness of a species was the average of 10-20 measurements made on different leaves. <br> <br>