Karina L. Speziale

Dealing with non-native species: what makes the difference in South America?

Non-native species have reached South American ecosystems and may be threatening the exceptional biodiversity of this region. However, people often value and exploit introduced species not knowing that they are non-natives, nor understanding their impacts. In this paper we analyze the trend of scientific research on introduced species in South America and whether a socio-cultural explanation could underlie the results by comparing them with European, North American and Australasian countries. We also controlled for research effort, which could reflect economic inequalities, by analyzing the articles published on introduced species in relation to the total number of articles published on related disciplines. Research trends suggest that non-native species are not of major concern for South American countries, there being less research on this topic in countries with higher biodiversity. Compared to other colonized countries such as the USA, New Zealand and Australia, research on non-native species was lagging and less abundant in South America, even when controlling for research effort. Historical and recent socio-cultural particularities may explain the similar attitudes and research input seen in South American countries and their Spanish and Portuguese colonizers. A generational amnesia, where younger generations descendent from European colonizers are not aware of past biological conditions, could be exacerbating this lack of concern. South American policies seem to reflect the low level of interest in non-native species shown by their citizens. National policies are poorly developed and mainly deal with alien species threatening productive systems. Given the strong cultural component of this dilemma, integrated ways to reverse this situation are needed, including education, international research collaboration, and a common South American policy.

Protecting Invaders for Profit

Humans have spread species to nonnative environments for generations. In turn, these species can become invasive, threatening native species. There has been much discussion about the best way to control invasive species and protect native species ([ 1 ][1]). However, one point has been overlooked:

Comment on "Worldwide evidence of a unimodal relationship between productivity and plant species richness"

Fraser et al. (Reports, 17 July 2015, p. 302) report a unimodal relationship between productivity and species richness at regional and global scales, which they contrast with the results of Adler et al. (Reports, 23 September 2011, p. 1750). However, both data sets, when analyzed correctly, show clearly and consistently that productivity is a poor predictor of local species richness.

Population Sex Ratios: Another Consideration in the Reintroduction - Reinforcement Debate?

Reintroduction or reinforcement (RorR) of wild populations is a common conservation strategy. Many conservation projects involve the release of individuals of poorly studied species. This may lead to inefficient results or negative impacts on the conservation efforts. Here, we provide new insights into the conservation implications and potential consequences of a skew in the sex ratio of released birds and of the number of birds supplemented for the demography of a long-lived dimorphic bird species, the Andean condor ( Vultur gryphus ). We demonstrate that a RorR conservation program may be less effective in conserving a species if the sex ratios of the releases and the recipient populations are not considered. We also show that releases can reduce population declines but only if carried out over long periods (i.e., several decades). This can mean high costs for release programs and the added challenge of maintaining programs over time. If RorR programs are to be implemented, bearing in mind the importance of properly assessing their effectiveness, we urge conservation researchers and managers to consider the implications of sex ratio biases for wild populations, and particularly for dimorphic species with sexually despotic behaviour.

The Effect of Introduced Species on Raptors

Abstract Biological invasions are considered one of the major threats to the Earths biota, and their prevention and control are widely recommended. A critical step is to gather information on the effects of introduced species on native species. In such analysis, it is important to consider both the negative effects and the fact that many nonnatives have become key components of existing ecosystems. The effects of nonnatives are particularly worrisome for raptors because raptors have high trophic positions and their ecological role can structure native communities. We here examine the effects of introduced species on raptors, as well as the interest in studying these effects, through a review of the published literature. The numbers of studies on raptors and introduced species as individual topics are rapidly increasing, but despite this we found few articles relating the two topics and fewer still with a clear aim of studying this relationship. Although the number of published reports we found was low, a...

Some Possible Anthropogenic Threats to Breeding Andean Condors (Vultur gryphus)

It is important to understand possible threats species might suffer, especially for those species that are difficult to study and often endangered, such as large, long-lived raptors. Particularly for these species, it may be difficult to reverse or remove the effects of anthropogenic threats to populations. One very costly time during a raptor’s lifetime is the breeding season (Alcock 1998, Hanssen et al. 2005). For large, long-lived raptors, the loss of a year’s reproductive investment and the loss of breeding areas can be detrimental for the population (Newton 1979). The Andean Condor (Vultur gryphus) is classified as ‘‘near threatened’’ globally and is included in CITES I, with some populations extirpated in part of its range in South America (BirdLife International 2004). Among the primary threat to condors is human-induced mortality, a result of the mistaken belief that condors will harm livestock. Farmers also poison and trap condors unintentionally when they try to kill pumas and foxes (see review in Lambertucci 2007). Andean Condors avoid feeding on roadkills (Speziale et al. 2008, Lambertucci et al. 2009a) and currently depend almost exclusively on exotic wild and domestic species managed by humans (Lambertucci et al. 2009b). However, human threats during the breeding season have not been studied. There are few data available on Andean Condor reproduction and nesting characteristics (del Hoyo et al. 1994, Lambertucci 2007), and only one published record of Andean Condors breeding in Argentina (Lambertucci and Mastrantuoni 2008). However, it is known that younger individuals have higher mortality rates than older individuals of this species (Temple and Wallace 1989). The few Andean Condor nests that have been described are generally situated on cliffs inaccessible to predators, with good winds in the immediate area (del Hoyo et al. 1994, Ferguson-Lees and Christie 2001). We here describe some characteristics of Andean Condor nest sites that might make this species vulnerable to human disturbance, particularly in areas of increasing human population.

Rock outcrops as potential biodiversity refugia under climate change in North Patagonia

Background: Under climate-change scenarios, rock outcrops, by providing microclimatically diverse habitats, different from those of surrounding zonal vegetation matrix, may serve as climatic refugia and thereby facilitate the persistence of specialist species. Aim: We tested whether rock outcrops of southern temperate latitudes could act as local refugia for a cold-adapted flora in the face of global warming. Methods: We related species composition of 50 outcrops and that of their surrounding vegetation to climatic data at local and regional scales to establish whether species distributions reflected differences that could indicate the existence of climatic refugia. Results: While at a regional scale, species composition of the outcrops across the study area was related to mean annual precipitation and mean annual maximum temperature, locally, southern faces of outcrops had different species and lower maximum temperatures than insolated north faces and surrounding vegetation plots. Conclusions: South faces of outcrops by providing cool microhabitats, and currently harbouring species not found in the surrounding zonal vegetation matrix, could serve as local refugia for heat-intolerant plants and other microthermic organism. The degree of ‘stability’ of these refugia will depend on the degree of future change in climate. Therefore, it is important to plan protected area networks that maximise local environmental heterogeneity, including the protection of rock outcrops both as refugia for cold-adapted species and as potential stepping stones that would allow dispersal of these species between supportive environments through unfavourable ones.

A call for action to curb invasive species in South America

Your call for more investigation into the ecology of urban habitats (see Nature doi:10.1038/ news.2010.359; 2010) is already being answered. In 1997, the US National Science Foundation’s Long-Term Ecological Research programme created urban research sites in Baltimore, Maryland, and in Phoenix, Arizona. And last year the foundation funded the Urban Long-Term Research Area Exploratory Awards with the US Forest Service to expand knowledge of urban natural resources and human interactions. These programmes attest to a coordinated and productive effort to incorporate urban research into mainstream ecology. Publications on this topic have mushroomed over the past two years: they include specialist journals (Urban Ecology, Urban Ecosystems); a ‘Cities’ special in Science (319, 739–775; 2008) and books such as Urban Herpetology, Urban Carnivores and Advances in Urban Ecology. Membership of the Urban Ecosystem Ecology section of the Ecological Society of America is growing fast — it is now the twelfth largest of 19 sections. There were 202 urban-related items presented at the society’s annual meeting last month, compared with just one in 1991. Although the number of published urban studies is still small, it is rapidly increasing. Only 0.4% of papers in nine leading ecology journals in 1993–98 dealt with cities or urban species (J. Collins et al. Am. Sci. 88, 416–425; 2000), compared with 2.5% of papers in 10 top ecology journals over the past 5 years (see go.nature.com/Lj7YAa). Urban environments were not Chinese journal finds 31% of submissions plagiarized

The southernmost parakeet might be enhancing pollination of a dioecious conifer

Fieldwork was funded by PIP 0758 (to K. L. Speziale) and by Fundacion Repsol (to J. L. Tella and F. Hiraldo).

An overlooked plant–parakeet mutualism counteracts human overharvesting on an endangered tree

The exponential growth of the human population often causes the overexploitation of resources and disruption of ecological interactions. Here, we propose that the antagonist effect of humans on exploited species might be alleviated with the advent of a second predator species. We focused on the complex interactions between an endangered conifer (Araucaria araucana) and two seed exploiters: the Austral parakeet (Enicognathus ferrugineus) and human seed collectors. We tested the importance of partial seed consumption by parakeets as an escape from human seed harvesting. Although parakeets frequently ate whole seeds, a substantial proportion of the seeds found under trees were only partially eaten and avoided by human seed collectors. These seeds germinated at a similar proportion but faster than intact seeds under laboratory conditions. Our results revealed an overlooked mutualism between parakeets and an endangered tree. Incomplete seed eating by parakeets, plus selection against these eaten seeds by humans, may enhance regeneration possibilities for this conifer species subject to human seed collection, turning the scale of the antagonism–mutualism continuum to the mutualistic side. In this context, parakeets might be providing an important service in those forests subject to human harvesting by allowing a fraction of seeds to escape human predation.