Translator Disclaimer
1 June 2013 The Effect of Introduced Species on Raptors
Karina L. Speziale, Sergio A. Lambertucci
Author Affiliations +
Abstract

Biological invasions are considered one of the major threats to the Earth's 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, articles indicating negative effects outnumbered articles showing positive ones. Negative effects identified included decrease in native prey and direct or indirect poisoning via poisons aiming to protect productive introduced species from predators or to control introduced pests. Positive effects identified included extension of distributional range facilitated by introduced species or nonnative species as a food source. Very importantly, native raptors can become dependent on introduced species, and any proposed control of the nonnative/introduced species merits careful evaluation. In conclusion, the effects of nonnative species on this key group of top predators and scavengers have been poorly considered, but merit special attention and specific design in future studies.

Las invasiones biológicas son una de las peores amenazas para la biodiversidad, y el control y la prevención de nuevas introducciones son ampliamente recomendados. Un paso fundamental en este proceso es la generación de conocimiento acerca del efecto de las especies introducidas sobre las especies nativas. En tal análisis, es importante considerar tanto los efectos negativos como el hecho de que algunas especies no nativas han llegado a convertirse en componentes clave de ecosistemas actuales. El efecto de las especies introducidas es especialmente preocupante para las rapaces debido a que, por su posición trófica y su rol ecológico, estas últimas pueden estructurar las comunidades nativas. Analizamos los impactos producidos por las especies introducidas sobre las rapaces y el interés en estudiarlos, mediante la revisión de la bibliografía publicada sobre el tema. Los estudios sobre rapaces y sobre especies introducidas como temas separados están aumentando rápidamente, pero a pesar de esto encontramos pocos artículos relacionando ambos temas y menos aún con un objetivo claro de estudiar dicha relación. Aunque el número de artículos encontrados fue bajo, los artículos que mostraban un efecto negativo han sido más numerosos que aquellos que indicaban un efecto positivo. Los efectos negativos identificados incluyeron la disminución de las presas nativas y el envenenamiento directo o indirecto producido por el veneno utilizado para la protección de especies introducidas económicamente productivas o para controlar especies introducidas consideradas pestes. Los impactos positivos identificados incluyeron la extensión del área de distribución facilitada por especies introducidas o las especies introducidas como fuente de alimento. Es importante notar que incluso las especies nativas pueden llegar a depender de las especies introducidas, y por lo tanto cualquier medida de control merece una cuidadosa evaluación. Concluyendo, las implicancias de las especies introducidas sobre este grupo clave de depredadores y carroñeros han sido poco consideradas pero merecen una atención especial y un diseño adecuado en estudios futuros.

The introduction of nonnative species can have severe consequences for native species and ecosystems (Carlsson et al. 2009, Vilà et al. 2011). As a result, the Convention on Biodiversity exhorted the contracting parties “to prevent the introduction, control or eradicate those alien species which threaten ecosystems, habitat or species.” Managers of eradication programs must consider, however, that invasive species have far-reaching effects throughout the entire ecosystem, which may cause a control program to result in unintended negative outcomes for native species (Tablado et al. 2010). To address the Convention's aims appropriately and effectively, knowledge of the full effects of introduced species over a wide range of ecosystems and species is required.

The study of biological invasions is rather a new discipline and is growing rapidly on some continents (Pyšek et al. 2008, Speziale et al. 2012). Studies show that nonnative species introductions may produce varying effects on native biotas (Gurevitch and Padilla 2004, Rodriguez 2006, Vilà et al. 2011). However, the analysis of the relationships between introduced species and certain taxa, including raptors, are poorly studied. A review of existing literature to find knowledge gaps may be helpful in guiding future research of the effects of this threat to biodiversity, particularly for raptors.

Raptors can directly promote high biodiversity through resource facilitation (i.e., food resources that are made available by raptors) and through trophic cascades by exerting top-down forces (Estes et al. 2001, Soulé et al. 2005, Sergio et al. 2007, 2008). They may also act as biodiversity indicators by being spatiotemporally associated with biodiversity (Sergio et al. 2008). As top predators and rare species, raptors can be threatened by species population changes at lower trophic levels (Begon et al. 2006, Wilson and Wolkovich 2011). Thus, it is important to monitor the effects of alien species on these top predators. The net effect of introduced species will depend on their capacity to modify the ecosystems and produce cascading effects (Crooks 2002). The goals of our study were (a) to analyze whether the volume of research on the relationship between raptors and exotic species follows the trend of the study of introduced species in general, and (b) to evaluate the effects of nonnative species on raptors by reviewing existing published studies.

Materials and Methods

We used the ISI Web of Knowledge engine to search for articles on biological invasions as related to raptor species. We first performed two separate searches to compare the trend of biological invasions science and raptor science over time. For that we searched title, abstract, and key words for the terms (inva* OR introduced OR alien OR exotic OR nonnative OR nonindigenous) in one search and for (condor OR raptor OR vulture) separately. Then we searched for published articles relating raptors and introduced species by using the following criteria: “(raptor OR vulture OR condor) AND (inva* OR introduced OR alien OR exotic OR nonnative OR nonindigenous).” We refined each search to identify only articles published in journals related to biological or environmental sciences. We performed the search in May 2012 and included articles published up to and including December 2011. We calculated the rate of publication of articles relating raptors and introduced species in respect to total publications in raptor science as a measure of the interest in the effect of nonnative species (hereafter the “exotics in raptor science index”). We conducted an analysis of covariance (ANCOVA) to compare the former rate of publication to the general interest in introduced species over the last 20 yr with the year as a covariate. For that we also calculated the ratio between publications in nonnative species (see criteria above) and the total publication in biological or environmental sciences as a measure of the interest in the study of introduced species in general (by searching the ISI Web of Science the word “species” and refining the search to identify only articles published in journals related to biological or environmental sciences (hereafter the “exotics in general science index”).

We then analyzed each article looking for information on the effects of the introduced species on raptor species to disentangle whether the overall described impact was positive, negative, or neutral. We defined a positive impact when the introduced species possibly favors raptors based on the information provided by the study (e.g., expanded distribution, increased nesting locations, increased food supply, or greater reproductive success). We considered an effect as negative when an introduced species directly or indirectly damages raptors in any way (e.g., via reduced prey availability, direct or indirect poisoning, etc.). We classified effects of introduced species as neutral when we could not classify them as either positive or negative for raptor species, according to the data provided by the study or if this information was ambiguous. We also analyzed trophic relationships affecting raptors, distinguishing between introduced primary producers (as habitat-modifiers), consumers (as prey for raptors and scavengers), top predators, and pathogens.

Results

The volume of both biological invasion research (Fig. 1A) and raptor research has increased greatly in the last 20 yr (Fig. 1B). However, although research analyzing the relationship between introduced species and raptors has increased, this increase was more moderate (Fig. 1C). Part of this trend may be related to the growth of raptor science per se, but it apparently does not reflect the great interest in biological invasions. We found that the interest in studying the effect of introduced species is much higher in general sciences than in raptor science: ANCOVA comparing publications on the effects of introduced species in raptor science (studies on introduced species and raptors over studies on only raptors) with that of general sciences (studies on introduced species within biological or environmental sciences over biological or environmental sciences studies in general) between 1991 and 2011 with the year as a covariate (F1,39  =  1468.4; P < 0.001; Fig. 2).

Figure 1

Trends of papers yielded by ISI Web of Science searches (see Methods for details) published on: (A) introduced species studies; (B) raptors studies; and (C) raptors in relation to introduced species. Notice the differences in y-axis scale among graphs.

i0892-1016-47-2-133-f01.tif

Figure 2

Differences in the interest in publishing the effects of introduced species in raptors science (Exotics in raptors science index) with that of general sciences (Exotics in general science index). Vertical bars denote standard errors. See Methods for more details.

i0892-1016-47-2-133-f02.tif

Our systematic search yielded a total of 97 articles that include in the same article one or more raptor species and one or more introduced species. After reviewing each one, we found that only 32% (31 articles) actually analyzed the relationship between raptors and nonnative species. We did not include those articles analyzing the effects of native species extending their distributions and thus considered newly arrived in a raptor ecosystem (e.g., Gutiérrez et al. 2006, Carrete et al. 2010), because in many cases it is not clear if it is a natural or human-mediated expansion. We included a total of 31 articles in our analyses. Of these 31 articles, only about 32% (10) had a clear a priori aim of studying nonnative species. We found studies of raptors and nonnative species on every continent (except for Antarctica; Fig. 3). Although the number of articles found for each continent was low, the effect of the introduced species on raptors appears to be widely distributed (Fig. 3). The analysis of the 31 articles showed that the outcome of nonnative species introductions could either be positive, negative, or neutral. In total, articles on the negative effects outnumbered articles on positive ones (16 to 11, respectively). Considering trophic relationships, based on the articles analyzed, producers modified raptors' habitats, generating indirect effects (Fig. 4). Introduced consumers (prey for raptors) and pathogens directly affect raptors, whereas introduced predators do so indirectly by competing for the same prey (Fig. 4). We found predators and pathogens only exerted negative effects (or neutral in one case), whereas the effect of producers and prey were both negative and positive (Fig. 4; Table 1).

Figure 3

Geographical distribution of the number of papers relating raptors with introduced species in each continent based on a search of articles in the ISI Web of Science (see Methods for details).

i0892-1016-47-2-133-f03.tif

Figure 4

Different positive (+) and negative (−) biotic interactions among introduced species and raptors found in a bibliographic search. See Table 1 for further details.

i0892-1016-47-2-133-f04.tif

Table 1

Results of the search of peer-reviewed studies in the ISI Web of Knowledge summarizing the aims of the study and effects of introduced species on raptors. The sign or letter within brackets indicates whether the effect is considered as positive (+), negative (−) or neutral (N) (see Methods for definitions).

i0892-1016-47-2-133-t01.tif

Table 1

Continued.

i0892-1016-47-2-133-t02.tif

Table 1

Continued.

i0892-1016-47-2-133-t03.tif

Table 1

Continued.

i0892-1016-47-2-133-t04.tif

Introduced primary producers causing habitat-modification effects on raptors were the focus of 39% (12/31) of the selected 31 articles, either by providing nest sites or by allowing the species to extend their distributions. Of these articles, 33% (4 of 12) indicated that raptors species were able to extend their distributions due to the new habitat conditions (e.g., finding new places to nest or perch, to rest or hunt; Table 1). Half of the studies (6 of 12) showed negative impacts of plantations or even-aged monotypic stands of introduced species (Table 1). These studies showed increased nest failures, reduced productivity, or even nest abandonment, arguing that it could be due to reduced prey availability in the new habitats. Two of these articles also reported a neutral impact. We also found two studies showing both positive (expanded distribution and use of human-modified land) and negative (changed roosting behavior and exotic plantations devoid of birds) effects at the same time (Table 1).

Introduced prey as part of raptors' diet was studied in 48% out of the 31 articles analyzed. Articles showing that raptor species feed on nonnative species, which may be considered as a positive outcome for raptors, made up almost half of diet studies (7 of 15; Table 1). The same proportion of studies (7 of 15) showed negative effects. Several of these latter ones (4 of 7) analyzed the effects of poison used to control introduced species, indirectly affecting raptors that fed on this prey. Another two studies evaluated lead poisoning in raptors caused by the consumption of introduced species contaminated or hunted with lead ammunition. Another article indicated the mortal effect of an antiinflammatory drug (diclofenac) used for cattle treatment (Table 1). Neutral effects were considered by three studies (two of which also showed a positive and a negative impact each and were considered above), indicating either that introduced species were minor parts of the raptors' diet or that a change in migration patterns was produced (Table 1).

The remaining articles (13% or 4 articles) of the 31 studies dealt with topics unrelated to introduced prey or to habitat modification. All but one showed negative effects on raptors (Table 1). These included competition with nonnative species (mammalian), and susceptibility to exotic pathogens. Only one of these articles reported a neutral effect.

Discussion

The study of nonnative species has become increasingly popular in recent years (Pyšek et al. 2008, Speziale et al. 2012). Similarly, there has been increased interest in the study of raptors. However, such an increase has not been seen in the study of raptors relative to introduced species and their effects. Any literature search can suffer from biases related to the databases or keywords used. It is likely, however, that any source of bias would only minimally affect the general patterns in publication efforts, and thus our general conclusions on the effects of nonnative species on raptors. Our results suggest that ecologists studying this group of species may not yet be highly concerned with the effect of one of the most important threats to wildlife: the introduction of nonnative species (Sala et al. 2000, Pereira et al. 2010). One fact that may be influencing this result is that raptors themselves do not commonly become invasive species.

We found that raptors are affected by nonnative species within their natural distribution areas, both negatively and positively, and that articles showing negative effects outnumbered articles showing positive ones. Regarding the latter, studies show that raptors can strongly rely on introduced species as a food source or for providing nesting habitat (Sarasola and Negro 2006, Gangoso et al. 2006, Lambertucci et al. 2009, Tablado et al. 2010). As introduced prey become abundant, the probability of a native predator using that prey also increases (Rodriguez 2006). Many native predators adapt to feeding on introduced prey, which can become an important part of their diet and some species can obtain a fitness advantage over species that do not adapt to utilizing the prey (Carlsson et al. 2009). This can lead to a high dependence on introduced species and therefore any change in their availability may have direct or indirect impacts on raptors. This can be a particularly critical factor when native resources decrease due to human intervention (Pavez et al. 2010, Akatani et al. 2011, Lambertucci and Speziale 2011). Some threatened raptor populations are in fact maintained by feeding on exotic resources (Chamberlain et al. 2005, Gangoso et al. 2006, Lambertucci et al. 2009).

Introduced primary producers also exert positive effects. Raptors take advantage of the availability of certain introduced trees, particularly when native vegetation is cut down or new plantations modify the habitat (Sarasola and Negro 2006, Akatani et al. 2011). Most studies that report species using novel habitats created by primary producers (sensu Hobbs et al. 2006; e.g., introduced species plantations) are not exhaustive and have not studied other fitness indicators such as breeding success or nestling survival, as the effects of introduced species were non-expected results (Wilson et al. 2009). Thus, the question remains as to whether the identified positive outcomes were truly positive.

Negative effects exerted by nonnative species ranged from poisoning and pathogen susceptibility to habitat loss and diminished native prey. Particularly important are the consequences of habitat modification by introduced primary producers, which structure the ecosystems in such a way to directly or indirectly provoke an array of negative effects. For example, the new habitat could be considered a sink for the newly arrived raptor species if the shift toward introduced species is detrimental for certain age classes (Cattau et al. 2010). Nonnative species plantations also provoke other negative effects such as nest failure or territory abandonment, and some may not be used by birds at all (Petit et al. 1999, Whitfield et al. 2007, Seaton et al. 2009).

Similarly, introduced prey species can have positive or negative effects on native raptors. Despite the fact that introduced prey increases the available food source for raptors, they can also provoke important negative effects. Fitness indicators for raptors feeding on the introduced apple snail (Pomacea insularum) in the U.S.A. showed that when raptors fed on this introduced prey, juveniles obtained a lower energetic reward than when feeding on native species, thus depressing juvenile survival (Cattau et al. 2010). Other studies have reported that raptors and scavengers can be indirectly affected when feeding in productive systems and that they can be negatively affected by drugs such as diclofenac, used to treat cattle (Naidoo et al. 2009). They can also die through poisoning by feeding on introduced prey, which has either been poisoned to reduce their threat to productive ecosystems, or poisons the raptor through ingestion of lead ammunition used during hunting of the introduced prey species (Eason et al. 2002, Church et al. 2006, Elliott et al. 2008, Lambertucci et al. 2011).

Conclusions

Several studies report some positive effects of nonnative species on raptors, particularly by providing bottom-up benefits (e.g., food). However, introduced species may also exert negative bottom-up effects (e.g., reduced juvenile survival or nesting failure) and we found that it is the negative effects that are more common and varied throughout the analyzed literature. These two contrasting results merit special attention. Control of or eradication actions for introduced species are often advised, particularly when negative effects of their presence have been recorded. However, the role that nonnative species play in the new ecosystem should be identified before programs are outlined. If raptors (or other native species) depend heavily on the introduced species, then target actions should focus first on how to overcome the problem of eradicating the nonnative species without affecting the species that depend on them (Lambertucci et al. 2009, Akatani et al. 2011). For introduced prey species, alternative native prey must be favored before the introduced one is eradiated. Similarly, considering raptors that rely on primary producers mostly for nesting, it is advisable to provide nesting structures or to recover native vegetation when eradicating introduced trees.

Raptors and scavengers perform a variety of keystone ecological services, such as disposing of carcasses, control of rodent populations and other top-down regulations (Sekercioglu et al. 2004, Sekercioglu 2006, Markandya et al. 2008, Newton 2010, Wilson and Wolkovich 2011), which can be affected by introduced species. Primarily it is important to design specific studies to analyze how nonnative species affect the roles raptors perform on ecosystems. It might be valuable to analyze the fitness and the viability of populations that have taken advantage of this novel (introduced) resource to test whether it really favors raptors. It is also important to analyze the role of introduced species in disturbing the native habitat, prey availability or the interactions within ecosystems. Study of the implications of nonnative species for this key group of top predators and scavengers is currently poorly considered and merits special attention and specific design in future studies.

Acknowledgments

We especially thank V. Penteriani for the initiative and his effort to produce this special issue of The Journal of Raptor Research in memory of Gary Bortolotti. We thank CONICET- PIP 0095 and ANPCyT –PICT 1156 (2010) for financial support. We also thank two anonymous reviewers and C. Wells for their comments on a previous version of this manuscript.

Literature Cited

1.

K Akatani T Matsuo and M Takagi 2011. Breeding ecology and habitat use of the Daito Scops Owl (Otus elegans interpositus) on an oceanic island. Journal of Raptor Research 45:315–323. Google Scholar

2.

C Beckmann and R Shine 2011. Toad's tongue for breakfast: exploitation of a novel prey type, the invasive cane toad, by scavenging raptors in tropical Australia. Biological Invasions 13:1447–1455. Google Scholar

3.

M Begon C.R Townsend and J.L Harper 2006. Ecology: from individuals to ecosystems. Wiley-Blackwell, Oxford, U.K. Google Scholar

4.

M.D Burgess R.A Black M.A.C Nicoll C.G Jones and K Norris 2009. The use of agricultural, open and forest habitats by juvenile Mauritius Kestrels Falco punctatus.. Ibis 151:63–76. Google Scholar

5.

N.O Carlsson O Sarnelle and D.L Strayer 2009. Native predators and exotic prey—an acquired taste? Frontiers in Ecology and the Environment 7:525–532. Google Scholar

6.

M Carrete S.A Lambertucci K Speziale O Ceballos A Travaini M Delibes F Hiraldo and J.A Donázar 2010. Winners and losers in human-made habitats: interspecific competition outcomes in two Neotropical vultures. Animal Conservation 13:390–398. Google Scholar

7.

C.E Cattau J Martin and W.M Kitchens 2010. Effects of an exotic prey species on a native specialist: example of the Snail Kite. Biological Conservation 143:513–520. Google Scholar

8.

C.P Chamberlain J.R Waldbauer K Fox-Dobbs S.D Newsome P.L Koch D.R Smith M.E Church S.D Chamberlain K.J Sorenson and R Risebrough 2005. Pleistocene to recent dietary shifts in California Condors. Proceedings of the National Academy of Sciences of the United States of America 102:16707. Google Scholar

9.

R.B Chandler A.M Strong and C.C Kaufman 2004. Elevated lead levels in urban House Sparrows: a threat to Sharp-shinned Hawks and Merlins? Journal of Raptor Research 38:62–68. Google Scholar

10.

M.E Church R Gwiazda R.W Risebrough K Sorenson C.P Chamberlain S Farry W Heinrich B.A Rideout and D.R Smith 2006. Ammunition is the principal source of lead accumulated by California Condors re-introduced to the wild. Environmental Science and Technology 40:6143–6150. Google Scholar

11.

J.A Crooks 2002. Characterizing ecosystem-level consequences of biological invasions: the role of ecosystem engineers. Oikos 97:153–166. Google Scholar

12.

T.A Crowl C.R Townsend and A.R McIntosh 1992. The impact of introduced brown and rainbow trout on native fish: the case of Australasia. Reviews in Fish Biology and Fisheries 2:217–241. Google Scholar

13.

O Curtis G Malan A Jenkins and N Myburgh 2005. Multiple-brooding in birds of prey: South African Black Sparrowhawks Accipiter melanoleucus extend the boundaries. Ibis 147:11–16. Google Scholar

14.

W.R.J Dean M.D Anderson S.J Milton and T.A Anderson 2002. Avian assemblages in native Acacia and alien Prosopis drainage line woodland in the Kalahari, South Africa. Journal of Arid Environments 51:1–19. Google Scholar

15.

C.T Eason E.C Murphy G.R.G Wright and E.B Spurr 2002. Assessment of risks of brodifacoum to non-target birds and mammals in New Zealand. Ecotoxicology 11:35–48. Google Scholar

16.

C.T Eason and E.B Spurr 1995. Review of the toxicity and impacts of brodifacoum on non-target wildlife in New Zealand. New Zealand Journal of Zoology 22:371–379. Google Scholar

17.

J.E Elliott A.L Birmingham L.K Wilson M McAdie S Trudeau and P Mineau 2008. Fonofos poisons raptors and waterfowl several months after granular application. Environmental Toxicology and Chemistry 27:452–460. Google Scholar

18.

J.A Estes K Crooks and R Holt 2001. Predators, ecological role of. Encyclopedia of Biodiversity 4:857–878. Google Scholar

19.

L Gangoso J.A Donázar S Scholz C.J Palacios and F Hiraldo 2006. Contradiction in conservation of island ecosystems: plants, introduced herbivores and avian scavengers in the Canary Islands. Biodiversity and Conservation 15:2231–2248. Google Scholar

20.

L Gangoso J.M Grande J.A Lemus G Blanco J Grande and J.A Donázar 2009. Susceptibility to infection and immune response in insular and continental populations of Egyptian Vulture: implications for conservation. PLoS ONE 4:e6333. Google Scholar

21.

C.R Griffin P.W.C Paton and T.S Baskett 1998. Breeding ecology and behavior of the Hawaiian Hawk. Condor 100:654–662. Google Scholar

22.

J Gurevitch and D.K Padilla 2004. Are invasive species a major cause of extinctions? Trends in Ecology and Evolution 19:470–474. Google Scholar

23.

R.J Gutiérrez M Cody S Courtney and A.B Franklin 2006. The invasion of Barred Owls and its potential effect on the Spotted Owl: a conservation conundrum. Biological Invasions 9:181–196. Google Scholar

24.

J.S Hall H.S Ip J.C Franson C Meteyer S Nashold J.L TeSlaa J French P Redig and C Brand 2009. Experimental infection of a North American raptor, American Kestrel (Falco sparverius), with highly pathogenic avian influenza virus (H5N1). PLoS ONE 4:e7555. Google Scholar

25.

R.J Hobbs S Arico J Aronson J.S Baron P Bridgewater V.A Cramer P.R Epstein J.J Ewel C.A Klink A.E Lugo D Norton D Ojima D.M Richardson E.W Sanderson F Valladares M Vilà R Zamora and M Zobel 2006. Novel ecosystems: theoretical and management aspects of the new ecological world order. Global Ecology and Biogeography 15:1–7. Google Scholar

26.

G Howald C.J Donlan K.R Faulkner S Ortega H Gellerman D.A Croll and B.R Tershy 2009. Eradication of black rats Rattus rattus from Anacapa island. Oryx 44:30–40. Google Scholar

27.

Y Kato and T Suzuki 2005. Introduced animals in the diets of the Ogasawara Buzzard, an endemic insular raptor in the Pacific Ocean. Journal of Raptor Research 39:173–179. Google Scholar

28.

S.A Lambertucci J.A Donázar A.D Huertas B Jiménez M Sáez J.A Sanchez-Zapata and F Hiraldo 2011. Widening the problem of lead poisoning to a South-American top scavenger: Lead concentrations in feathers of wild Andean Condors. Biological Conservation 144:1464–1471. Google Scholar

29.

S.A Lambertucci and K.L Speziale 2011. Protecting invaders for profit. Science 332:35. Google Scholar

30.

S.A Lambertucci A Trejo S Di Martino J.A Sánchez-Zapata J.A Donázar and F Hiraldo 2009. Spatial and temporal patterns in the diet of the Andean Condor: ecological replacement of native fauna by exotic species. Animal Conservation 12:338–345. Google Scholar

31.

G Malan and E.R Robinson 2001. Nest-site selection by Black Sparrowhawks Accipiter melanoleucus: implications for managing exotic pulpwood and sawlog forests in South Africa. Environmental Management 28:195–205. Google Scholar

32.

A Markandya T Taylor A Longo M.N Murty S Murty and K Dhavala 2008. Counting the cost of vulture decline—an appraisal of the human health and other benefits of vultures in India. Ecological Economics 67:194–204. Google Scholar

33.

A.L Monserrat M.C Funes and A.J Novaro 2005. Dietary response of three raptor species to an introduced prey in Patagonia. Revista Chilena de Historia Natural 78:425–439. Google Scholar

34.

J.L Morrison and L.M Phillips 2000. Nesting habitat and success of the Chimango Caracara in southern Chile. Wilson Bulletin 112:225–232. Google Scholar

35.

V Naidoo K Wolter R Cuthbert and N Duncan 2009. Veterinary diclofenac threatens Africa's endangered vulture species. Regulatory Toxicology and Pharmacology 53:205–208. Google Scholar

36.

I Newton 2010. Population ecology of raptors. T. and A.D. Poyser, Ltd., London, U.K. Google Scholar

37.

P Olsen P Fuller and T Marples 1993. Pesticide-related eggshell thinning in Australian raptors. Emu 93:1–11. Google Scholar

38.

J.H Pascoe R.C Mulley R Spencer and R Chapple 2011. Diet analysis of mammals, raptors and reptiles in a complex predator assemblage in the Blue Mountains, eastern Australia. Australian Journal of Zoology 59:295–301. Google Scholar

39.

E.F Pavez G.A Lobos and F.M Jaksic 2010. Long-term changes in landscape and in small mammal and raptor assemblages in central Chile. Revista Chilena de Historia Natural 83:99–111. Google Scholar

40.

H.M Pereira P.W Leadley V ProenÇa R Alkemade J.P.W Scharlemann J.F Fernandez-Manjarrés M.B Araújo P Balvanera R Biggs W.W.L Cheung L Chini H.D Cooper E.L Gilman S Guénette G.C Hurtt H.P Huntington G.M Mace T Oberdorff C Revenga P Rodrigues R.J Scholes U.R Sumaila and M Walpole 2010. Scenarios for global biodiversity in the 21st century. Science 330:1496–1501. Google Scholar

41.

L.J Petit D.R Petit D.G Christian and H.D.W Powell 1999. Bird communities of natural and modified habitats in Panama. Ecography 22:292–304. Google Scholar

42.

P Pyšek D.M Richardson J Pergl V JarošÍk Z Sixtová and E Weber 2008. Geographical and taxonomic biases in invasion ecology. Trends in Ecology and Evolution 23:237–244. Google Scholar

43.

A.C Robinson R.T Larsen J.T Flinders and D.L Mitchell 2010. Chukar seasonal survival and probable causes of mortality. Journal of Wildlife Management 73:89–97. Google Scholar

44.

L.F Rodriguez 2006. Can invasive species facilitate native species? Evidence of how, when, and why these impacts occur. Biological Invasions 8:927–939. Google Scholar

45.

O.E Sala F.S Chapin III J.J Armesto E Berlow J Bloomfield R Dirzo E Huber-Sanwald L.F Huenneke R.B Jackson A Kinzig R Leemans D.M Lodge H.A Mooney M Oesterheld N.L Poff M.T Sykes B.H Walker M Walker and D.H Wall 2000. Global biodiversity scenarios for the year 2100. Science 287:1770–1774. Google Scholar

46.

J.H Sarasola and J.J Negro 2006. Role of exotic tree stands on the current distribution and social behaviour of Swainson's Hawk, Buteo swainsoni in the Argentine Pampas. Journal of Biogeography 33:1096–1101. Google Scholar

47.

R Seaton J.D Holland E.O Minot and B.P Springett 2009. Breeding success of New Zealand Falcons (Falco novaeseelandiae) in a pine plantation. New Zealand Journal of Ecology 33:32–39. Google Scholar

48.

C.H Sekercioglu 2006. Increasing awareness of avian ecological function. Trends in Ecology & Evolution 21:464–471. Google Scholar

49.

C.H Sekercioglu G.C Daily and P.R Ehrlich 2004. Ecosystem consequences of bird declines. Proceedings of the National Academy of Sciences 101:18042–18047. Google Scholar

50.

F Sergio T Caro D Brown B Clucas J Hunter J Ketchum K McHugh and F Hiraldo 2008. Top predators as conservation tools: ecological rationale, assumptions, and efficacy. Annual Review of Ecology, Evolution, and Systematics 39:1–19. Google Scholar

51.

F Sergio L Marchesi P Pedrini and V Penteriani 2007. Coexistence of a generalist owl with its intraguild predator: distance-sensitive or habitat-mediated avoidance? Animal Behaviour 74:1607–1616. Google Scholar

52.

M.E Soulé J.A Estes B Miller and D.L Honnold 2005. Strongly interacting species: conservation policy, management, and ethics. BioScience 55:168–176. Google Scholar

53.

K.L Speziale S.A Lambertucci M Carrete and J.L Tella 2012. Dealing with non-native species: what makes the difference in South America? Biological Invasions 14:1609–1621. Google Scholar

54.

W.E Stout A.G Cassini J.K Meece J.M Papp R.N Rosenfield and K.D Reed 2005. Serologic evidence of West Nile virus infection in three wild raptor populations. Avian Diseases 49:371–375. Google Scholar

55.

Z Tablado J.L Tella J.A Sánchez-Zapata and F Hiraldo 2010. La paradoja de los efectos positivos a largo plazo de un langostino norteamericano sobre una comunidad de depredadores europeos. Conservation Biology 24:1230–1238. Google Scholar

56.

M Vilà J.L Espinar M Hejda P.E Hulme V Jarošík J.L Maron J Pergl U Schaffner Y Sun and P Pyšek 2011. Ecological impacts of invasive alien plants: a meta-analysis of their effects on species, communities and ecosystems. Ecology Letters 14:702–708. Google Scholar

57.

D.P Whitfield A.H Fielding M.J.P Gregory A.G Gordon D.R.A McLeod and P.F Haworth 2007. Complex effects of habitat loss on Golden Eagles Aquila chrysaetos. Ibis 149:26–36. Google Scholar

58.

E.E Wilson and E.M Wolkovich 2011. Scavenging: how carnivores and carrion structure communities. Trends in Ecology and Evolution 26:129–135. Google Scholar

59.

M.W Wilson S Irwin D.W Norriss S.F Newton K Collins T.C Kelly and J O'Halloran 2009. The importance of pre-thicket conifer plantations for nesting Hen Harriers Circus cyaneus in Ireland. Ibis 151:332–343. Google Scholar

60.

E Yensen D Quinney K Johnson K Timmerman and K Steenhof 1992. Fire, vegetation changes, and population fluctuations of Townsend ground-squirrels. American Midland Naturalist 128:299–312. Google Scholar
The Raptor Research Foundation, Inc.
Karina L. Speziale and Sergio A. Lambertucci "The Effect of Introduced Species on Raptors," Journal of Raptor Research 47(2), 133-144, (1 June 2013). https://doi.org/10.3356/JRR-12-00003.1
Received: 27 June 2012; Accepted: 1 October 2012; Published: 1 June 2013
JOURNAL ARTICLE
12 PAGES


SHARE
ARTICLE IMPACT
Back to Top