Naturalized Parrots of the World by Pruett-Jones Stephen;

Author:Pruett-Jones, Stephen;
Language: eng
Format: epub
Publisher: Princeton University Press
Published: 2021-05-15T00:00:00+00:00

PART II

CASE STUDIES

10

GLOBAL INVASION

SUCCESS OF THE

ROSE-RINGED PARAKEET

Hazel A. Jackson

INTRODUCTION

Invasive species are among the most significant drivers of biodiversity loss and one of the largest global conservation challenges of today. Humans have been trading species for millennia, and contemporary global patterns of invasive species have been shaped by such human-mediated transport of plant and animal species (Hulme 2009). However, not all species introduced to regions outside their native range are considered invasive. Only species that establish, disperse, and have a detrimental impact upon native biota are considered invasive. Improvements in global transport networks over time have increased connectivity of human populations and led to increasing frequencies of biological invasions (McKinney and Lockwood 1999). Invasive alien species now represent an increasingly urgent economic, societal, and environmental problem. Their rapid spread, competitive nature, and transmission of infectious diseases pose threats to global biodiversity, and invasive species are considered one of the five main causes of global biodiversity loss, alongside climate change, pollution, overexploitation, and habitat loss (Millennium Ecosystem Assessment 2005).

The parrots (Psittaciformes) form one of the most distinctive bird groups. They are also one of the most endangered groups of birds in the world: 95 (26.8%) of the 354 known parrot species are currently threatened with extinction, and a further 36 species are classified as “near threatened” (Jetz et al. 2014). Over the past 500 years, approximately 163 avian extinctions have occurred across the globe, including some 20 parrot species (12%), half of which were island endemics (Collar 2000; Butchart et al. 2006). Major reasons for declining endemic parrot populations include invasive species, poaching, habitat loss, and the pet trade (Cheke and Hume 2009; Perrin 2012).

Interestingly, while removal from their native habitat for the pet trade has caused the decline of many endemic parrots, the popularity of parrots as pets and their global transport have contributed to some 54 species (16% of total living species) currently breeding outside their native range, with the more widely distributed species—Monk Parakeet (Myiopsitta monachus), Orange-winged Amazon (Amazona amazonica), Green Parakeet (Psittacara holochlorus), Rose-ringed Parakeet (Psittacula krameri), and Rosy-faced Lovebird (Agapornis roseicollis)—being the most successful at establishing populations in non-native areas (Menchetti and Mori 2014). Parrot establishment in non-native environments is a result of numerous factors; in addition to the birds’ popularity as pets, and high numbers being traded and bred, they are highly synanthropic, appearing to be adapted to surviving in a wide variety of environmental conditions (Duncan et al. 2003; Cassey et al. 2004).

The world’s most successful and prolific of all non-native parrots is the Rose-ringed Parakeet, a species now established in over 35 countries, across five continents (Fig. 10.1). This medium to large, emerald-green parakeet is native to Asia and sub-Saharan Africa. There are four recognized subspecies (Forshaw 2010): two subspecies are native to Asia (P. k. borealis, found in eastern Pakistan, throughout northern India, Nepal, and Burma; and P. k. manillensis, found in southern India and Sri Lanka), and two native to Africa (P. k. krameri, found from Senegal to western Uganda and southern Sudan; and P.

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