Miguel A. Rendón

Global economy interacts with climate change to jeopardize species conservation: The case of the greater flamingo in the Mediterranean and West Africa

The conservation of many species depends on sustainable economic activities that shape their habitats. The economic use of these anthropogenic habitats may change quickly owing to world trade globalization, market reorientations, price volatility or shifts in subsidy policies. The recent financial crisis has produced a global impact on the world economy. How this may have affected the use of habitats beneficial to biodiversity has not yet been documented. However, consequences could be particularly acute for species sensitive to climate change, jeopardizing long-term conservation efforts.

Estimating partial observability and nonlinear climate effects on stochastic community dynamics of migratory waterfowl

1. Understanding the impact of environmental variability on migrating species requires the estimation of sequential abiotic effects in different geographic areas across the life cycle. For instance, waterfowl (ducks, geese and swans) usually breed widely dispersed throughout their breeding range and gather in large numbers in their wintering headquarters, but there is a lack of knowledge on the effects of the sequential environmental conditions experienced by migrating birds on the long-term community dynamics at their wintering sites. 2. Here, we analyse multidecadal time-series data of 10 waterfowl species wintering in the Guadalquivir Marshes (SW Spain), the single most important wintering site for waterfowl breeding in Europe. We use a multivariate state-space approach to estimate the effects of biotic interactions, local environmental forcing during winter and large-scale climate during breeding and migration on wintering multispecies abundance fluctuations, while accounting for partial observability (observation error and missing data) in both population and environmental data. 3. The joint effect of local weather and large-scale climate explained 31·6% of variance at the community level, while the variability explained by interspecific interactions was negligible (<5%). In general, abiotic conditions during winter prevailed over conditions experienced during breeding and migration. Across species, a pervasive and coherent nonlinear signal of environmental variability on population dynamics suggests weaker forcing at extreme values of abiotic variables. 4. Modelling missing observations through data augmentation increased the estimated magnitude of environmental forcing by an average 30·1% and reduced the impact of stochasticity by 39·3% when accounting for observation error. Interestingly however, the impact of environmental forcing on community dynamics was underestimated by an average 15·3% and environmental stochasticity overestimated by 14·1% when ignoring both observation error and data augmentation. 5. These results provide a salient example of sequential multiscale environmental forcing in a major migratory bird community, which suggests a demographic link between the breeding and wintering grounds operating through nonlinear environmental effects. Remarkably, this study highlights that modelling observation error in the environmental covariates of an ecological model can be proportionally more important than modelling this source of variance in the population data.

Incubating terns modify risk-taking according to diurnal variations in egg camouflage and ambient temperature

Studies of risk-taking by breeding birds have frequently addressed the effect of brood value on the decisions taken by incubating birds when predators approach their nests. However, leaving eggs unattended during predator disturbance may expose embryos to other potentially harmful factors, to which parent birds should respond when making decisions about when to leave or return to their nest. In this study, we show that diurnal changes in flushing behaviour of incubating terns from nests during predator approach were affected by egg camouflage, the terns allowing a closer approach to individual nests when the eggs appeared better camouflaged. Return times to the nests were affected by ambient temperature, with the terns shortening such times at high ambient temperatures, thus diminishing the risk of egg overheating. As a whole, our results show that the decisions of the birds on when to leave or return to their nests depended on shifting payoffs, as a consequence of diurnal variations in both the thermal risks incurred by embryos and egg crypsis. Environmental costs of risk-taking, such as those considered here, should be addressed in studies of risk-taking by breeding birds. This type of study may have implications for our knowledge of cognitive processes that affect risk-taking.Significance statementWhen a predator approaches a nest, the incubating bird has to decide at which moment to leave the nest, which may be affected by environmental factors that may hamper embryo viability. We studied flushing/returning behaviour of incubating little terns Sternula albifrons in response to disturbance and show that risk-taking was affected by the occurrence of simultaneous environmental threats according to shifting fitness payoffs. When the eggs appeared better camouflaged, which usually occurred around midday, the terns allowed closer approach to individual nests. The terns shortened the return to their nests with increasing ambient temperature, which took place at midday. Thus, our results show that, by adjusting their responses to shifting payoffs, the terns modulated the risks incurred by their offspring, as eggs were less time exposed to direct solar radiation in midday, when the risk of overheating was higher.

Latitudinal variation in biophysical characteristics of avian eggshells to cope with differential effects of solar radiation

Abstract Solar radiation is an important driver of animal coloration, not only because of the effects of coloration on body temperature but also because coloration may protect from the deleterious effects of UV radiation. Indeed, dark coloration may protect from UV, but may increase the risk of overheating. In addition, the effect of coloration on thermoregulation should change with egg size, as smaller eggs have higher surface‐volume ratios and greater convective coefficients than larger eggs, so that small eggs can dissipate heat quickly. We tested whether the reflectance of eggshells, egg spottiness, and egg size of the ground‐nesting Kentish plover Charadrius alexandrinus is affected by maximum ambient temperature and solar radiation at breeding sites. We measured reflectance, both in the UV and human visible spectrum, spottiness, and egg size in photographs from a museum collection of plover eggshells. Eggshells of lower reflectance (darker) were found at higher latitudes. However, in southern localities where solar radiation is very high, eggshells are also of dark coloration. Eggshell coloration had no significant relationship with ambient temperature. Spotiness was site‐specific. Small eggs tended to be light‐colored. Thermal constraints may drive the observed spatial variation in eggshell coloration, which may be lighter in lower latitudes to diminish the risk of overheating as a result of higher levels of solar radiation. However, in southern localities with very high levels of UV radiation, eggshells are of dark coloration likely to protect embryos from more intense UV radiation. Egg size exhibited variation in relation to coloration, likely through the effect of surface area‐to‐volume ratios on overheating and cooling rates of eggs. Therefore, differential effects of solar radiation on functions of coloration and size of eggshells may shape latitudinal variations in egg appearance in the Kentish plover.

Dynamic signalling using cosmetics may explain the reversed sexual dichromatism in the monogamous greater flamingo

Colourful plumage is typical of males in species with conventional sex roles, in which females care for offspring and males compete for females, as well as in many monogamous species in which both sexes care for offspring. Reversed sexual dichromatism—more colourful females than males—is predominant in species with sex role reversal. In the latter species, males care for offspring and females compete for mates, the mating system is mainly polyandrous and there is reversed size dimorphism—females are larger than males. Here, we document a case of reversed dichromatism, in the greater flamingo Phoenicopterus roseus, in which there is no sex role reversal and no reversed size dimorphism. Although theoretical models postulate that cases of reversed dichromatism should be rare among monogamous ornamented birds, our findings show that the use of cosmetics might be a mechanism for the occurrence of more ornamented females than males. Indeed, the concentrations of carotenoids in the uropygial secretions used as make-up were higher in females than in males. Apparently, there was a trade-off between coloration and antioxidant defence, as the concentrations of carotenoids in the uropygial secretions were lower during chick provisioning than in other periods, contrary to those in plasma. In this system, the application of make-up would act as a dynamic signal, which would allow a rapid reallocation of resources used for signalling among functions depending on needs. Cases like this may have evolved to signal the ability to provide parental care when females are more physiologically stressed than males.Significance statementFor species in which there is no sex role reversal, but females are ornamented and the resources allocated to ornaments are important for offspring viability, it has even been suggested that females should be less ornamented than males. This may be because for females, it would be better to invest directly in fecundity rather than in costly ornaments. We show a case of reversed sexual dichromatism in a monogamous bird with no sex role reversal, the greater flamingo, where females apply make-up over feathers. In the case of this species, there could be directional male mate preferences for female plumage coloration because the costs of signalling would not affect breeding investment in females, since cosmetic coloration is not used after it is no longer required, thus allowing the resources used in make-up (carotenoids) to be used in other functions.

Variaciones entre especies de anfibios en sus respuestas morfológicas a la presencia de depredadores nativos e introducidos

Fallas Henriquez, A., Molina-Murillo, S. 2017. Methodological proposal to quantify and to compensate the agroecosystem services generated by the good agricultural practices of small-farmers. Ecosistemas 26(3): 89-102. Doi.: 10.7818/ECOS.2017.26-3.11 A diversified and less intensive management of agricultural systems produces agroecosystem services that are often not estimated nor compensated in developing countries. The main objective of this study was to create a tool that allows quantification of agroecosystemic services (SAgro) generated in agroforestry peasant farms, and additionally estimate compensation values. Following an initial test in 2013 on 10 farms, an important bibliographical review was carried out, the consultation of experts, and the evaluation in 2015 of 50 farms at the national level, most of them members of the National Agroforestry Union (UNAFOR) of Costa Rica. As a result, a tool was developed to measure in an agile, flexible and economical way the ecosystem services generated by good agricultural practices produced by small producers (peasants) both for their agricultural system as well as the forest system. We also found that the size of farms is not necessarily the determining factor for the production of agroecosystem services, but rather the type of management practices and investments made. In this process, it was estimated that with an average compensation of US

Status, distribution and long term changes in the waterbird community wintering in Doñana, south-west Spain

271.6 per agricultural hectare per year, the production or maintenance of agroecosystem services could be encouraged through good agricultural practices.