7 research outputs found
The Effects of Larval Nutrition on Reproductive Performance in a Food-Limited Adult Environment
It is often assumed that larval food stress reduces lifetime fitness regardless
of the conditions subsequently faced by adults. However, according to the
environment-matching hypothesis, a plastic developmental response to poor
nutrition results in an adult phenotype that is better adapted to restricted
food conditions than one having developed in high food conditions. Such a
strategy might evolve when current conditions are a reliable predictor of future
conditions. To test this hypothesis, we assessed the effects of larval food
conditions (low, improving and high food) on reproductive fitness in both low
and high food adults environments. Contrary to this hypothesis, we found no
evidence that food restriction in larval ladybird beetles produced adults that
were better suited to continuing food stress. In fact, reproductive rate was
invariably lower in females that were reared at low food, regardless of whether
adults were well fed or food stressed. Juveniles that encountered improving
conditions during the larval stage compensated for delayed growth by
accelerating subsequent growth, and thus showed no evidence of a reduced
reproductive rate. However, these same individuals lost more mass during the
period of starvation in adults, which indicates that accelerated growth results
in an increased risk of starvation during subsequent periods of food stress
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Genomic analysis reveals genetic distinctiveness of the Paiute Cutthroat Trout oncorhynchus clarkii seleniris
The Paiute Cutthroat Trout (PCT) Oncorhynchus clarkii seleniris is classified as a subspecies within the greater Cutthroat Trout O. clarkii ssp. complex and is federally listed as threatened under the Endangered Species Act. However, genetic studies to date have revealed very little genetic differentiation between the PCT and its closest relative, the Lahontan Cutthroat Trout (LCT) O. clarkii henshawi. These results casted doubt on whether the PCT is a genetically distinct subspecies or merely a phenotypic variant of the LCT. Here, we present a genomic analysis of Cutthroat Trout subspecies and populations to resolve the genetic and phylogenetic relationship between PCT and LCT. Our results demonstrate substantial genetic structure and differentiation between PCT and LCT populations. In contrast to current thinking, our phylogenetic reconstructions show the PCT to be a distinct evolutionary lineage that diverged from LCT before the LCT differentiated into its current populations (i.e., rather than PCT divergence due to geographic isolation from an LCT population in the Carson River). We conclude that the PCT is genetically distinct from the LCT
Turkey's globally important biodiversity in crisis
Turkey (Turkiye) lies at the nexus of Europe, the Middle East, Central Asia and Africa. Turkey's location, mountains, and its encirclement by three seas have resulted in high terrestrial, fresh water, and marine biodiversity. Most of Turkey's land area is covered by one of three biodiversity hotspots (Caucasus, Irano-Anatolian, and Mediterranean). Of over 9000 known native vascular plant species, one third are endemic. Turkey faces a significant challenge with regard to biodiversity and associated conservation challenges due to limited research and lack of translation into other languages of existing material. Addressing this gap is increasingly relevant as Turkey's biodiversity faces severe and growing threats, especially from government and business interests. Turkey ranks 140th out of 163 countries in biodiversity and habitat conservation. Millennia of human activities have dramatically changed the original land and sea ecosystems of Anatolia, one of the earliest loci of human civilization. Nevertheless, the greatest threats to biodiversity have occurred since 1950, particularly in the past decade. Although Turkey's total forest area increased by 5.9% since 1973, endemic-rich Mediterranean maquis, grasslands, coastal areas, wetlands, and rivers are disappearing, while overgrazing and rampant erosion degrade steppes and rangelands. The current "developmentalist obsession", particularly regarding water use, threatens to eliminate much of what remains, while forcing large-scale migration from rural areas to the cities. According to current plans, Turkey's rivers and streams will be dammed with almost 4000 dams, diversions, and hydroelectric power plants for power, irrigation, and drinking water by 2023. Unchecked urbanization, dam construction, draining of wetlands, poaching, and excessive irrigation are the most widespread threats to biodiversity. This paper aims to survey what is known about Turkey's biodiversity, to identify the areas where research is needed, and to identify and address the conservation challenges that Turkey faces today. Preserving Turkey's remaining biodiversity will necessitate immediate action, international attention, greater support for Turkey's developing conservation capacity, and the expansion of a nascent Turkish conservation ethic. (C) 2011 Published by Elsevier Ltd