Drought-induced Suppression of Female Fecundity in a Capital Breeder

Coping with drought? Effects of extended drought conditions on soil invertebrate prey and diet selection by a fossorial amphisbaenian reptile

Arid climates are characterized by a summer drought period to which animals seem adapted. However, in some years, the drought can extend for unusually longer periods. Examining the effects of these current extreme weather events on biodiversity can help to understand the effects of climate change, as models predict an increase in drought severity. Here, we examined the effects of "unusual" extended drought on soil invertebrate prey availability and on diet composition (based on fecal contents) and diet selection of a fossorial amphisbaenian, the checkerboard worm lizard Trogonophis wiegmanni. Weather data show interannual variations in summer drought duration. The abundance and diversity of soil invertebrates in spring were high, and similar to those found in a "normal" early autumn, after some rain had ended with the summer drought. In contrast, in years with "unusual" extended drought, abundance, and diversity of soil invertebrates in early autumn were very low. Also, there were seasonal changes in amphisbaenians' diet; in autumn with drought, prey diversity, and niche breadth decreased with respect to spring and autumns after some rain had fallen. Amphisbaenians did not eat prey at random in any season, but made some changes in prey selection that may result from drought-related restrictions in prey availability. Finally, in spite that amphisbaenians showed some feeding flexibility, their body condition was lower in autumn than in spring, and much lower in autumn with drought. If extended drought became the norm in the future, amphisbaenians might suffer important negative effects for their health state.

Small Hydropower Plants' Proliferation Would Negatively Affect Local Herpetofauna

Hydropower plants (HPPs) have a strong environmental impact on freshwater wetlands. Small diversion HPPs (SDHPPs) with 0.1–10 MW of installed power, redirect water from small mountainous rivers into several-kilometer-long tubes, disrupting complex dynamics of local aquatic food webs and their interactions with neighbor terrestrial food webs. It certainly affects local aquatic communities, but it is often neglected that two highly threatened vertebrate groups—amphibians and reptiles—which live in and around these wetlands, could be affected as well. In the Balkan peninsula, a part of Southeastern Europe, SDHPPs recently became very attractive and profitable for potential investors after they were proclaimed as eligible for subsidies from the national budget. As a result, in year 2020, the maximal projected number of SHPPs in the Balkans increased to 4,556. According to the literature data, ~28% of amphibian species in the Balkan Peninsula use small rivers and streams in the upper parts of watersheds as feeding, breeding and/or nursery habitats. Additionally, 38% of the total number of reptile species in Europe are registered in the hilly/mountainous areas of the peninsula, and 33% of these species strictly need humid habitats. The attempt of this mini-review is to present the facts which show that SHPPs and DSHPPs, in the way they are currently being installed, present harmful energy solution for the biodiversity of the mountain parts of Balkan peninsula, particularly for local amphibian and reptile populations which rely on lotic aquatic ecosystems and/or humid terrestrial habitats.

Water deprivation compromises maternal physiology and reproductive success in a cold and wet adapted snake Vipera berus

Droughts are becoming more intense and frequent with climate change. These extreme weather events can lead to mass mortality and reproduction failure, and therefore cause population declines. Understanding how the reproductive physiology of organisms is affected by water shortages will help clarify whether females can adjust their reproductive strategy to dry conditions or may fail to reproduce and survive. In this study, we investigated the consequences of a short period of water deprivation (2 weeks) during early pregnancy on the physiology and behaviour of a cold- and wet-adapted ectotherm (Vipera berus). We also examined water allocation to developing embryos and embryonic survival. Water-deprived females exhibited significant dehydration, physiological stress and loss of muscle mass. These effects of water deprivation on water balance and muscle loss were correlated with the number of developing embryos. While water-deprived females maintained water transfer to embryos at the expense of their own maintenance, water deprivation also led to embryonic mortality. Overall, water deprivation amplifies the reproductive costs of water allocation to support embryonic development. The deleterious impacts of water deprivation on female current reproductive performance and on potential survival and future reproduction could lead to severe population declines in this species.

Additive effects of temperature and water availability on pregnancy in a viviparous lizard

One of the greatest current threats to biodiversity is climate change. However, understanding of organismal responses to fluctuations in temperature and water availability is currently lacking, especially during fundamental life-history stages such as reproduction. To further explore how temperature and water availability impact maternal physiology and reproductive output, we used the viviparous form of the European common lizard (Zootoca vivipara) in a two-by-two factorial design manipulating both hydric and thermal conditions, for the first time. We collected blood samples and morphological measurements during early pregnancy and post-parturition to investigate how water availability, temperature and a combination of the two influence maternal phenology, morphology, physiology and reproductive output. We observed that dehydration during gestation negatively affects maternal physiological condition (lower mass gain, higher tail reserve mobilization) but has little effect on reproductive output. These effects are mainly additive to temperature regimes, with a proportional increase in maternal costs in warmer environments. Our study demonstrates the importance of considering combined effects of water and temperature when investigating organismal responses to climate changes, especially during periods crucial for species survival such as reproduction.