Amphibian responses to livestock use of wetlands: new empirical data and a global review

Abstract

Pastureland currently occupies 26% of Earth's ice-free land surface. As the global human population continues to increase and developing countries consume more proteinrich diets, the amount of land devoted to livestock grazing will only continue to rise. To mitigate the loss of global biodiversity as a consequence of the ever-expanding amount of land converted from native habitat into pastureland for livestock grazing, an understanding of how livestock impact wildlife is critical. While previous reviews have examined the impact of livestock on a wide variety of taxa, there have been no reviews examining how global livestock grazing affects amphibians. We conducted both an empirical study in south-central Florida examining the impact of cattle on amphibian communities and a quantitative literature review of similar studies on five continents. Our empirical study analyzed amphibian community responses to cattle as both a binary (presence/absence) variable, and as a continuous variable based on cow pie density. Across all analyses, we were unable to find any evidence that cattle affected the amphibian community at our study site. The literature review returned 46 papers that met our criteria for inclusion. Of these studies, 15 found positive effects of livestock on amphibians, 21 found neutral/mixed effects, and 10 found negative effects. Our quantitative analysis of these data indicates that amphibian species that historically occurred in closedcanopy habitats are generally negatively affected by livestock presence. In contrast, opencanopy amphibians are likely to experience positive effects from the presence of livestock, and these positive effects are most likely to occur in locations with cooler climates and/or greater precipitation seasonality. Collectively, our empirical work and literature review demonstrate that under the correct conditions well-managed rangelands are able to support diverse assemblages of amphibians. These rangeland ecosystems may play a critical role in protecting future amphibian biodiversity by serving as an "off-reserve" system to supplement the biodiversity conserved within traditional protected areas.

Preliminary Analysis of the Diet of Triturus carnifex and Pollution in Mountain Karst Ponds in Central Apennines

“…The differences in the chemical and physical conditions observed in the sampled sites may be the direct consequence of such kind of pasture management: in fact, while sheep do not usually wade the ponds, cows and horses are frequently observed in them. Thus, ponds are subject to livestock wading and defecation, determining an alteration of water quality, while drinking troughs or tanks does not usually undergo these pressures [29,59]. This could explain the notable differences between the natural sampled sites and the artificial ones, in terms of abiotic conditions.…”

“…Such physical and chemical modification affects both the macroinvertebrates and the vertebrates in ponds. In particular, the macroinvertebrate community structure changes and negatively influences the amphibians' community; this cascade effect depends on the environmental conditions of the ponds, because of a complex interaction between abiotic and biotic components [22,28,29]. Further, amphibians themselves show high sensitivity to climate [30,31], contaminants [32][33][34] and habitat changes [35,36].Despite their highly threatened status [37,38] and their importance in food webs [39,40], amphibians' dietary ecology in high altitude lakes or ponds has been poorly investigated so far [41,42].In this paper, we analyze how the ponds' alteration due to dense livestock presence could affect amphibians' diet, through the diet analysis of the Italian crested newt, Triturus carnifex, at mountain sampling sites.…”

“…Such physical and chemical modification affects both the macroinvertebrates and the vertebrates in ponds. In particular, the macroinvertebrate community structure changes and negatively influences the amphibians' community; this cascade effect depends on the environmental conditions of the ponds, because of a complex interaction between abiotic and biotic components [22,28,29]. Further, amphibians themselves show high sensitivity to climate [30,31], contaminants [32][33][34] and habitat changes [35,36].…”

Temporary pond loss as a result of pasture abandonment: exploring the social-ecological drivers and consequences on amphibians

“…Livestock (especially cattle and buffalo) grazing and trampling can prohibit the establishment of pond vegetation which otherwise would fill the ponds and/or increase their evapotranspiration (Boyce, Durtsche & Fugal, 2011; Pyke & Marty, 2005; Warren et al, 2007; Warren & Collins, 1994). Extensive grazing with livestock (cattle, buffalo) was related to the persistence of amphibian ponds in Europe and other continents (reviewed by Howell et al, 2019). The increase in scrub cover on pastures as a result of farming abandonment can result in loss of temporary ponds through the acceleration of desiccation (Boyce, Durtsche & Fugal, 2011; Ruiz, 2008).…”

“…Farming landscapes can be rich in temporary ponds (Hartel & von Wehrden, 2013) because human activities can result in temporary pond formation. Especially the traditional grazing with cattle can maintain optimal amphibian habitats, especially in Europe (Howell et al, 2019). Cattle grazing may contribute to the maintenance of temporary ponds due to trampling and removal of vegetation which would fill these ponds and/or accelerate their drying (Pyke & Marty, 2005; Winter, 2000).…”