A New Remarkable Dwarf Sedge (Carex phylloscirpoides, Cyperaceae) from Northern Chile, with Insights on the Evolution of AustralCarexsectionRacemosae

Abstract—We describe a new remarkable dwarf and apparently acaulescent species ofCarex(Cyperaceae) from the Andes of northern Chile:Carex phylloscirpoides. Morphological and molecular data (two nuclear and three plastid DNA regions) were used to study the phylogenetic placement and systematic relationships of this species, which resulted in its assignment toCarexsectionRacemosae. However, despite being related to the other three species of the section present in the Southern Cone based on phylogenetic evidence, it displays a number of unusual morphological features. In addition, it is geographically disjunct and genetically differentiated from them. A preliminary conservation assessment was performed which resulted in the proposal of the Critically Endangered category at the global level under IUCN guidelines. We discuss the biogeographic and ecological peculiarities of the new species and its allies, with emphasis in the high number of acaulescent sedges present in South America. The features ofC. phylloscirpoidesemphasize its unique evolutionary position and its rarity highlights its conservation importance, especially in the context of the South American Andean flora.

Andean Flora as a Source of New Repellents against Insect Pests: Behavioral, Morphological and Electrophysiological Studies on Sitophilus zeamais (Coleoptera: Curculionidae)

Sitophilus zeamais (Motschulsky) is considered as one of the most destructive foodstuff pests. Due to their efficiency, low toxicity for mammalians and low environmental impact, plant-derived essential oils (EOs) are promising tools for pest control. In particular, the OEs extracted from Lamiaceae are considered among the most bioactive in terms of repellent and/or insecticidal effect. Here, we investigated the repellence of the EOs extracted from two aromatic plant species typical of the flora of the Ecuadorian Andes, Clinopodium tomentosum and C. nubigeum, against adults of S. zeamais. The behavioral assays carried out at concentrations ranging from 0.7 to 23.9 μL L−1 air in a two-way static olfactometer showed a significant repellent effect starting from the concentration of 8.4 mL L−1 air both for the EO of C. nubigenum and C. tomentosum. We also carried out a complete structural analysis of the antenna of S. zeamais using scanning (SEM) and transmission electron microscopy (TEM), in order to characterize the olfactory sensilla equipment. In this species, there is no sexual dimorphism also as regards to the antennal morphology and the sensilla type and distribution. We identified six type of sensilla, among which at least three types (Sensillum Trichoideum 1, Sensillum Trichoideum 2 and Grooved Peg Sensillum) can be considered as olfactory. Electroantennography (EAG) recordings carried out on S. zeamais revealed a positive dose-response to both EOs, without differences between the two sexes.

Paleoclimatic and archaeological evidence from Lake Suches for highland Andean refugia during the arid middle-Holocene

Severe aridity during the mid-Holocene, ca. 8.0–4.0 kyr BP, led to extreme ecological stress in the tropical Andes. Here, we report paleolimnological and archeological data from Lake Suches in southern Peru (70° 24’ 12” W, 16° 55’ 35” S) spanning 13.6–4.4 kyr BP. Integrated paleoclimate and archeological data reveal that moisture was locally available and the basin served as an ecological refugium throughout the mid-Holocene. Mid-Holocene aridity was established no later than 7.2 kyr BP, with maximum aridity ca. 5.5–4.8 kyr BP. However, water levels in Lake Suches were sustained throughout peak middle-Holocene aridity, even as other systems desiccated. Isotopic enrichment of water in Lake Suches (δ18Olake) and extensive wetlands (δ18Obofedal) surrounding the lake indicate prolonged residence time. These reservoirs, combined with elevation-linked hydrographic factors, mitigated mid-Holocene net decreases in atmospheric moisture. Archeological data from Suches indicate successive population increases beginning ca. 11.0–9.8 kyr BP as drier but more stable early Holocene conditions were established regionally. Population maxima in Suches during the mid-Holocene/mid-Archaic period ca. 9.0–7.0 kyr BP coincide with peak aridity in the Titicaca and Atacama systems, as well as documented archeological hiatuses in these regions. Population decreases coincide with peak aridity recorded in Lake Suches ca. 6.0–5.0 kyr BP, but the basin was never fully abandoned. Evidence for refugial microenvironments is key to understanding the persistence of human populations and other endemic Andean flora and fauna during the highly adverse climates of the middle-Holocene. We outline several mechanisms which likely explain the formation of refugia linked to bofedales and hydrographic characteristics of Suches. Understanding refugial dynamics will be key to understanding the effects of past climatic change, as well as addressing current warming and decreased precipitation trends in the tropical Andes.

An unusual new record of Baccharis (Asteraceae) from the Peruvian Andes and its relation with the northern limit of the dry puna

Background and Aims: The knowledge of the richness and distribution of the flora in the Peruvian Andes is scarce; about 70 taxonomic novelties have been reported for this area in the last decade, a large part belonging to the Asteraceae. The objective of this paper is to contribute to the knowledge of this flora through a new record of Baccharis acaulis. In addition, the distribution pattern of this species is examined.Methods: As part of floristic inventories in the high Andes of Peru, various field trips were carried out, several plant specimens were collected, among them a previously unreported species, which was identified by consulting some specialists and confirmed using taxonomic keys. Furthermore, predicting species distribution based on ecological niche modeling was made use the machine learning algorithm Maxent with the bioclimatic variables of the WorldClim database.Key results: A species of the genus Baccharis was registered for the first time for the flora of Peru. This species is recognized for its unique habit; it is a rhizomatous herb in which the aboveground part consists of small leaf rosettes surrounding a solitary capitulum. The species was collected in the south of the Peruvian Andes. This record extends the known distribution of the species considerably to the north.Conclusions: This record suggests the need to continue studying the Andean flora, as well as the links of their distribution patterns with the phytogeographical regions.

Recent origin of Neotropical orchids in the world’s richest plant biodiversity hotspot

Abstract• The Andean mountains of South America are the most species-rich biodiversity hotspot worldwide with about 15% of the world’s plant species, in only 1% of the world’s land surface. Orchids are a key element of the Andean flora, and one of the most prominent components of the Neotropical epiphyte diversity, yet very little is known about their origin and diversification.• We address this knowledge gap by inferring the biogeographical history and evolutionary dynamics of the two largest Neotropical orchid groups (Cymbidieae and Pleurothallidinae), using two unparalleled, densely-sampled orchid phylogenies (including 400+ newly generated DNA sequences), comparative phylogenetic methods, geological and biological datasets.• We find that the majority of Andean orchid lineages only originated in the last 15 million years. Most Andean lineages are derived from lowland Amazonian ancestors, with additional contributions from Central America and the Antilles. Species diversification is correlated with Andean orogeny, and multiple migrations and re-colonizations across the Andes indicate that mountains do not constrain orchid dispersal over long timescales.• Our study sheds new light on the timing and geography of a major Neotropical radiation, and suggests that mountain uplift promotes species diversification across all elevational zones.