Trees, shrubs and herbs of the coastal Myrtaceae swamp forest (Región de La Araucanía, Chile): a dataset

Species lists are fundamental for knowledge of species diversity in regions subject to intense anthropogenic pressure, especially in poorly-studied ecosystems. The dataset comes from an inventory conducted in 30 fragments of Myrtaceae swamp forest, located in an agroforestry matrix landscape of the coastal La Araucanía Region in Chile. The data collection was carried out using line transect sampling, which was traced through the core of each fragment orientated towards its longest axis. The dataset provides a record of 55 species (24 trees, 1 vine [as a host], 16 herbs and 15 shrubs) including accidental epiphytes (n = 7), hemiparasites (n = 4), host (n = 10) and additionally woody debris (n = 36). The most frequent trees in the landscape were Myrceugenia exsucca (n = 36 records) and Blepharocalyx cruckshanksii (n = 33 records), species that were also the most common hosts. Drimys winteri was a companion species, other trees and shrubs generally being rarely observed, as was the case of the introduced species (Prunus avium, Rubus constrictus and Ulex europaeus). Branches were the most common microhabitat for hemiparasites. Within this group, Lepidoceras chilense was the most frequent species. For accidental epiphytes, Drimys winteri, which commonly grows on the ground (soil), were the most common species found in the main trunk crotch. Some unusual observations were the climber Cissus striata as host of Tristerix corymbosus (hemiparasite) and Tristerix corymbosus as host of Lepidoceras chilense (hemiparasite). This study represents a landscape-scale sample of the swamp forest, which is distributed in a dispersed pattern over a large stretch of Chile. The data were collected from 30 forest patches (from 0.05 to 936 ha), located on the coast of the Araucanía. The database includes the presence of 55 species of vascular plants in 356 records. The main novelty of this contribution is the systematic classification of species under six traits, never before reported in the same database: (i) condition (coarse woody debris, fallen log, live, snag), (ii) habit (herb, shrub, tree), (iii) growth microhabitat (e.g. tree trunk, branch, main trunk crotch), (iv) growth form (accidental epiphyte, hemiparasite, terricolous, vegetative), (v) host species (as appropriate) and (vi) relative location of the species in the sampled patch and surrounding areas (core, border, matrix). Species not previously observed in these forests were: Gavilea spp., Hieracium spp., Lophosoria quadripinnata, Berberis actinacantha, Gaultheria phillyreifolia, Ovidia pillo-pillo, Amomyrtus meli and Caldcluvia paniculata. In addition, two introduced species are novelties for the catalogue of vascular plants of Chile (Cupressus macrocarpa and Prunus avium). Several of these ecosystem traits are indeed new reports for these types of forests (e.g. accidental epiphytes, fallen logs, species-host relationship); at the same time, more frequent data (i.e. species composition, habit) are found in different contributions, making the comprehensive process of analysis difficult. Accordingly, the database is made available in this manuscript.

Breeding system of Tristerix corymbosus (Loranthaceae), a winter-flowering mistletoe from the southern Andes

Harsh climates should select for breeding systems that uncouple reproductive success from unpredictable pollinator service, such as autonomous, within-flower pollination and autogamous seed set. I assessed the breeding system and overall pollinator dependence of Tristerix corymbosus (L.) Kuijt, a mistletoe that blooms during the snowy winters of the southern Andes and whose flowers are visited by the hummingbird Sephanoides sephaniodes. The nectar produced by T. corymbosus represents the main food for overwintering populations of S. sephanioides, one of the principal pollinators in the temperate forest of southern South America. Hand-pollination experiments showed that this plant is fully self-compatible, with only a slight advantage of cross- over self-pollen during either germination or early tube growth. Despite self-compatibility, T. corymbosus exhibited a limited capacity for autonomous, within-flower pollination and high dependence on its hummingbird pollinator for full seed set. Thus, dwindling hummingbird populations should compromise reproductive success in this potential keystone plant species.