Benefits of protected areas for nonbreeding waterbirds adjusting their distributions under climate warming

Climate warming is driving changes in species distributions and community composition. Many species have a so-called climatic debt, that is, shifts in range lag behind shifts in temperature isoclines. Inside protected areas (PAs), community changes in response to climate warming can be facilitated by greater colonization rates by warm-dwelling species, but also mitigated by lowering extirpation rates of cold-dwelling species. An evaluation of the relative importance of colonization-extirpation processes is important to inform conservation strategies that aim for both climate debt reduction and species conservation. We assessed the colonization-extirpation dynamics involved in community changes in response to climate inside and outside PAs. To do so, we used 25 years of occurrence data of nonbreeding waterbirds in the western Palearctic (97 species, 7071 sites, 39 countries, 1993–2017). We used a community temperature index (CTI) framework based on species thermal affinities to investigate species turnover induced by temperature increase. We determined whether thermal community adjustment was associated with colonization by warm-dwelling species or extirpation of cold-dwelling species by modeling change in standard deviation of the CTI (CTI_SD). Using linear mixed-effects models, we investigated whether communities in PAs had lower climatic debt and different patterns of community change than communities outside PAs. For CTI and CTI_SD combined, communities inside PAs had more species, higher colonization, lower extirpation, and lower climatic debt (16%) than communities outside PAs. Thus, our results suggest that PAs facilitate 2 independent processes that shape community dynamics and maintain biodiversity. The community adjustment was, however, not sufficiently fast to keep pace with the large temperature increases in the central and northeastern western Palearctic. Our results underline the potential of combining CTI and CTI_SD metrics to improve understanding of the colonization-extirpation patterns driven by climate warming.     

Vegetation cover and rainfall seasonality impact nutrient loss via runoff and erosion in the Colombian Andes

Regional Environmental Change - Mountain ecosystems provide key services to a large portion of the population in the tropics. However, they are particularly vulnerable to regional environmental...     

Allelochemical effects of ergoline alkaloids fromIpomoea parasitica onHeliothis virescens

Lysergol, elymoclavine and three other van Urk-positive alkaloids were identified by 2D chromatography in the seed extract ofIpomoea parasitica. The presence of the same ergoline alkaloids was also demonstrated in vegetative tissue ofI. parasitica. Heliothis virescens larvae reared on a diet containing an alkaloid extract ofI. parasitica showed an increase in the consumption index and a reduction in the effiency of conversion of food. No difference was observed in the approximated digestibility. The percentages of pupation and emergence were reduced and the malefemale ratio was altered in insects fed on a diet containing the alkaloid extract ofI. parasitica or lysergol. The increases in the concentration of ergoline alkaloids inI. parasitica at the seedling stage and at flowering support the theory that these compounds play a defensive role against herbivory in the plant.     

Effects of prenatal yolk androgens on armaments and ornaments of the ring-necked pheasant

Mothers may profoundly affect offspring phenotype and performance by adjusting egg components, including steroid hormones. We studied the effects of elevated prenatal testosterone (T) exposure in the ring-necked pheasant on the expression of a suite of male and female traits, including perinatal response to stress, immune response, growth, and secondary sexual traits. Prenatal T levels were increased by injecting the yolk of unincubated eggs with physiological doses of the hormone. Yolk T injection resulted in a reduced length of male tarsal spurs, a trait which positively predicts male success in intra- and intersexual selection and viability, whereas no direct effect on male wattle characteristics or plumage traits of either sex was observed. Female spur length was also negatively affected by T, but to a lesser extent than in males. In addition, the covariation between male secondary sexual traits, which are reliable quality indicators, differed between T and control males, suggesting that the manipulation may have altered the assessment of overall male quality by other males and females. In conclusion, the negative effects of elevated yolk T on spur length, a trait which positively predicts male fitness, coupled with the lack of effects on growth or other traits in both sexes, provided limited evidence for mothers being subjected to a trade-off between positive and negative consequences of yolk T deposition on offspring traits and suggest that directional selection for reduced yolk T levels may occur in the ring-necked pheasant.     

Using shell middens to assess effects of fishing on queen conch ( Strombus gigas ) populations in Los Roques Archipelago National Park, Venezuela

Queen conch, Strombus gigas, is a commercially important gastropod that has been exploited throughout the Caribbean islands for thousands of years. Shell middens in the region are the physical record of a long-term fishery and their study can provide valuable information on selectivity patterns followed by fishermen and on resulting morphological shifts reflected by shells. In this study, we surveyed 27 middens located at Los Roques, Venezuela, to assess pre-Columbian and modern fisheries and measure their impact on local populations of queen conch. Pre-Columbian middens, covering a period of approximately 350 years of exploitation (1160–1540 A.D.), were mostly composed of adult shells (89%) and mean length of catch was estimated at 22.4 ± 0.2 cm (mean ± SE). A decrease in mean length of catch was observed throughout the modern fishery regime, estimated at 22.2 ± 0.3 cm in 1950–1971 and 20.0 ± 0.3 cm in 1990–1995. Higher proportions of immature individuals ranging from 48 to 67% were found in modern middens. Additionally, a decrease in mean length of mature individuals was detected throughout the modern fishery regime. The appearance of younger and smaller specimens is considered as a sign of heavy exploitation of local populations of queen conch during modern fisheries. Pre-Columbian middens in contrast, permitted to establish a relative baseline from which to compare values registered throughout modern times.     

Environmental externalities and efficiency measurement

Production of desirable outputs often produces by-products that have harmful effects on the environment. This paper investigates technologies where the biggest good output producer is not the greatest polluter, i.e. technologies located on the downward-sloping segment of the frontier depicted in Färe et al. (1989). Directional distance functions and Data Envelopment Analysis techniques are used to define an algorithm that allows them to be identified empirically. Furthermore, we show that in such situations producers can contribute social goods, i.e. reducing polluting wastes, without limiting their capacity to maximise production of marketable output. Finally, we illustrate our methodology with an empirical application to a sample of Spanish ceramic tile producers.     

Estimating the magnitude of morphoscapes: how to measure the morphological component of biodiversity in relation to habitats using geometric morphometrics

Ecological indicators are currently developed to account for the different facets of loss of biological diversity due to direct or indirect effects of human activities. Most ecological indicators include species richness as a metric. Others, such as functional traits and phylogenetic diversity, account for differences in species, even when species richness is the same. Here, we describe and apply a different indicator, called morphoscape dimension, accounting for morphological variability across habitats in a geographical region. We use the case of ground beetles (Coleoptera: Carabidae) in four different habitats in the Po Plain in Northern Italy to exemplify how to quantify the magnitude of the morphological space (i.e. the dimension of the morphoscape) occupied by the species in each habitat using geometric morphometrics. To this aim, we employed a variety of metrics of morphological disparity related to univariate size, and more complex multivariate shape and form. Our ‘proof of concept’ suggests that metrics assessing size and form might largely tend to simply mirror the information provided by species richness, whereas shape morphoscape disparity may be able to account for non-trivial differences in species traits amongst habitats. This is indicated by the woodland morphoscape being on average bigger than that of crops, the most species-rich habitat, despite having almost 20% less species. We conclude suggesting that the analysis of morphoscape dimension has the potential to become a new additional and complimentary tool in the hands of conservation biologists and ecologists to explore and quantify habitat complexity and inform decisions on management and conservation based on a wide set of ecological indicators.     

Rareness and specialization in plant-pollinator networks

Most rare species appear to be specialists in plant-pollinator networks. This observation could result either from real ecological processes or from sampling artifacts. Several methods have been proposed to overcome these artifacts, but they have the limitation of being based on visitation data, causing interactions involving rare visitor species to remain undersampled. We propose the analysis of food composition in bee trap nests to assess the reliability of network specialization estimates. We compared data from a plant-pollinator network in the Monte Desert of Villavicencio Nature Reserve, Argentina, sampled by visit observation, and data from trap nests sampled at the same time and location. Our study shows that trap nest sampling was good for estimating rare species degree. The rare species in the networks appear to be more specialized than they really are, and the bias in the estimation of the species degree increases with the rareness. The low species degree of these rare species in the visitation networks results from insufficient sampling of the rare interactions, which could have important consequences for network structure.