Geographic space, relief, and soils predict plant community patterns of Asteraceae in rupestrian grasslands, Brazil

Abstract

We investigated the effects of geographic distance and environmental heterogeneity on Asteraceae communities in the rupestrian grasslands of the Espinhaço Range, southeastern Brazil. Asteraceae species composition and relative abundance were sampled in 21–1 ha plots distributed across park conservation units, comprising an environmental gradient in soils and relief (elevation and slope). We found high levels of heterogeneity overall in assemblages of herbaceous and woody Asteraceae species at the intermediate spatial scale of this study (10–100 km). We found that both relief and soil properties (texture and total exchangeable bases) explained significant proportions of variation in community composition, suggesting that definitions or expansions of conservation units should span the highest possible variability in observed relief and soil values. We also found that Asteraceae distribution exhibited strong spatial structure independent of environmental variation, reinforcing the need to consider conservation across larger areas. Considering the dystrophic character of the soils found in the Espinhaço Range and the few differences in the fertility observed between the sampling units, our results also support the hypothesis that plant distributions in the tropics are controlled by a hierarchy of environmental gradients, where variables such as altitude and exchangeable bases and Al texture are important predictors in low‐fertility soils. We suggest that Asteraceae could be a model family for conservation planning in other countries and regions because it is particularly well represented in open and montane areas of the Neotropics in general. Abstract in Portuguese is available with online material.

Diamonds and Daisies: Floristics and Conservation of Asteraceae in One of Brazil’s Major Centers of Endemism

“…Closer investigation of the endangered species that were not collected showed that two of them are common either in the northern "Bahia" CdoE or in the more westerly Serra Geral de Goia´s. For species where wide-scale distributional data could not explain absence, microdistributional differences or microhabitat specialization, as proposed by Chaves et al (2019), stochastic distribution, or a combination of these are the most likely explanations. Percentages of gravel, sand, and silt in the soil explained 67% of the difference between mycorrhizal communities (Carvalho et al, 2012).…”

“…both parks, and in many cases, frequency data have been obtained from RAPELD modules (see Chaves et al, 2019). Five such endangered species have been recorded from protected areas for the first time (species marked with b in Table 2).…”

“…Botanical collections were made (SISBIO Licence 40530-1 issued to the first author on August 6, 2013) using two different methods, the RAPELD protocol (Magnusson et al, 2005), with a reduction to 7 ha per module and some modifications to suit the campo rupestre environment (see Chaves et al, 2019), and traditional floristic collecting, between August 2013 and October 2014. For the RAPELD protocol, three sample modules were established, each of which with 21 sample units.…”

“…Since many species have not yet been sampled phylogenetically in the CdoE, phylogenetic approaches would be very incomplete. Asteraceae, the chosen surrogate taxon, is suitable for the following reasons: (a) it presents a wide variety of growth forms, including some that are specific to campo rupestre (Clarke et al, 2013;Lusa, Appezzato-da-Gl oria, Loeuille, Bartoli, & Ciccarelli, 2014) and (b) it is speciesrich, taxonomically diverse and responsive to environmental drivers (Chaves et al, 2019) making it a good surrogate of functional diversity, a highly informative biodiversity metric (Gallardo, Gasc on, Quintana, & Com ın, 2011). Asteraceae genera have been used to evaluate the efficiency of the conservation unit network in Mexico (Villaseñor, Ibarra, & Ocaña, 1998 Species Link 2017a, 2017b, 2017c, 2017d.…”

“…Within this Plateau, there are two protected areas: Rio Preto State Park (PERP) and Sempre Vivas National Park (PNSV). Chaves et al (2019) have shown that the main environmental predictors of Asteraceae distribution patterns in these two protected areas are either edaphic, that is, sum of bases and levels of aluminum (Al), clay, and sand, or associated with elevation and slope. Combined spatial and environmental components performed better at explaining Asteraceae floristic and relative abundance than either component by itself.…”