Prioritizing Conservation of Coastal Ponds for Wintering Redheads

The Laguna Madres of Texas, USA, and Tamaulipas, Mexico, are the most important wintering areas for redheads (Aythya americana) as most of the continental population winters in these lagoons. Redheads forage in the saline waters of the Laguna Madre and make daily flights to coastal freshwater ponds on the adjacent mainland to drink. The abundance and spatial distribution of coastal ponds varies depending on precipitation and can influence the foraging pressure on adjacent seagrass meadows. We conducted weekly aerial surveys to monitor coastal pond use by wintering redheads from mid-October through mid-March along the entire length of the Laguna Madre of Texas, during 2000–2003 and in 2012–2014. We developed 3 parameters to provide a measure of biological value of each coastal pond to redheads: amount of foraging habitat within 10 km of each pond, water permanence of the pond, and the potential to distribute redheads if inundated. During 101 aerial surveys across 5 years of study, we identified 140 coastal ponds that were used by redheads. We developed a prioritization scheme to identify wetlands that remain inundated in all years and targeted them for conservation protection. We identified those coastal ponds that, if enhanced through increasing their water permanence, would provide additional drinking sites during dry years and help distribute redheads on more foraging habitat, thereby reducing potential overgrazing on seagrass meadows. We identified 3,624 ha of foraging habitat (21.5% of all foraging habitat) in the lower Laguna Madre that had no coastal ponds within a 10-km radius and, thus, was proximal to potential areas for coastal pond creation. Our results provide guidance for resource managers to protect, enhance, or create coastal ponds to reduce foraging pressure on seagrass meadows in the Laguna Madre and help sustain future populations of wintering redheads. © 2021 The Wildlife Society.     

Viola lilliputana sp. nov. (Viola sect. Andinium, Violaceae), one of the world's smallest violets, from the Andes of Peru

A new violet species of Viola Sect. Andinium, Viola lilliputana, is described from a single dry puna locality on an extensive intermontane plateau southeast of Cerro Palla Palla in the high Andes of Ayacucho Department in southern Peru. This diminutive rosulate violet is evidently among the smallest in the world and probably one of the smallest terrestrial dicots. It belongs to a distinctive species group with pinnatifid leaves that is endemic to central and southern Peru, including V. hillii, V. membranacea and V. weibelii. The new species is similar to V. weibelii in its large, strongly adnate stipules, elongate leaf lobes and dilated unappendaged style with ventral stigmatic orifice. It differs conspicuously from all other members of the pinnatifid-leaved group in its conduplicate leaf blades, straight, mostly nonoverlapping, oblong-lanceolate to broadly elliptical lobes with obtuse to rounded apices, and large basally fused pedicel bractlets. Despite many new collections of vascular plants from the high Andes of Peru and northern Bolivia in recent decades, this distinctive new species is still known only from its type locality, collected on the Iltis-Ugent expedition from November 1962 to January 1963.     

NATURALLY OCCURRING MITOCHONDRIAL DNA HAPLOTYPES EXHIBIT METABOLIC DIFFERENCES: INSIGHT INTO FUNCTIONAL PROPERTIES OF MITOCHONDRIA

Linking the mitochondrial genotype and the organismal phenotype is of paramount importance in evolution of mitochondria. In this study, we determined the differences in catalytic properties of mitochondria dictated by divergences in the siII and siIII haplogroups of Drosophila simulans using introgressions of siII mtDNA type into the siIII nuclear background. We used a novel in situ method (permeabilized fibers) that allowed us to accurately measure the consumption of oxygen by mitochondria in constructed siII‐introgressed flies and in siIII‐control flies. Our results showed that the catalytic capacity of the electron transport system is not impaired by introgressions, suggesting that the functional properties of mitochondria are tightly related to the mtDNA haplogroup and not to the nuclear DNA or to the mito‐nuclear interactions. This is the first study, to our knowledge, that demonstrates a naturally occurring haplogroup can confer specific functional differences in aspects of mitochondrial metabolism. This study illustrates the importance of mtDNA changes on organelle evolution and highlights the potential bioenergetic and metabolic impacts that divergent mitochondrial haplogroups may have upon a wide variety of species including humans.     

Hop functions downstream of Nkx2.1 and GATA6 to mediate HDAC-dependent negative regulation of pulmonary gene expression

Hop is an unusual homeodomain protein that was first identified in the developing heart where it functions downstream of Nkx2.5 to modulate cardiac gene expression. Hop functions through interactions with histone deacetylase (HDAC) 2 to mediate repression of cardiac-specific genes, and recent studies show that HDAC activity and HDAC2 expression are decreased in people with chronic obstructive pulmonary disease. Here, we show that Hop is expressed in airway epithelium coincident with HDAC2, and expression is induced by the combination of dexamethasone and cAMP in parallel with induction of surfactant protein gene expression. Hop functions in the developing pulmonary airway, acting downstream of Nkx2.1 and GATA6, to negatively regulate surfactant protein expression. Loss of Hop expression in vivo results in defective type 2 pneumocyte development with increased surfactant production and disrupted alveolar formation. Thus Hop represents a novel regulator of pulmonary maturation that is induced by glucocorticoids to mediate functionally important HDAC-dependent negative feedback regulation.