Changes in distribution and habitat suitability

The consequences of anthropocentric actions on the planet have been discussed for several decades, and the scenario for 2100 presents a high risk to global biodiversity, requiring changes necessary to reverse the current situation (Sala et al. Reference Sala, Chapin and Armesto2000). The estimate considering the worst-case scenario is the loss of 34% of global species diversity. According to Sala et al. (Reference Sala, Chapin and Armesto2000) there are several actions that harm global biodiversity, such as habitat destruction, mainly caused by the conversion of native vegetation to agriculture and urbanisation. Anthropogenic climate change acts as a pervasive stressor on avian biodiversity, driving significant shifts in community dynamics and population persistence (Brooker et al. Reference Brooker, Young and Watt2007; Sala et al. Reference Sala, Chapin and Armesto2000). It is predicted that by 2100 climate change will lead to a loss of habitat of up to 12% (Sala et al. Reference Sala, Chapin and Armesto2000). According to Dirzo et al. (Reference Dirzo, Young, Galetti, Ceballos and Isaac2014), in addition to habitat loss and climate change, pollution and the introduction of exotic species are reducing fauna in various parts of the planet.

In Brazil, rapid rates of global climate change are coupled with recent increases in deforestation rates. In 2020, deforestation in the Amazon increased by 30% when compared with 2019, a change that has wide-reaching effects on the hydrological cycle. By disturbing the ‘flying rivers’ (the large volume of water vapour that hangs above the Amazonian canopy due to transpiration), which are transported by air currents to other regions, deforestation in the Amazon will affect precipitation rates in the Pantanal wet seasons. Additionally, almost one-third of the Pantanal was destroyed by massive wildfires in 2020, putting all plant and animal species that reside within this biome at risk (Berlink et al. Reference Berlink, Lima, Pereira, Carvalho, Paula and Thomas2022; Fonseca et al. Reference Fonseca, Amorim, Cardoso, Ribeiro, Ferreira and Kirchhoff2021).

Phenological and reproductive alterations

Salimi et al. (Reference Salimi, Almuktar and Scholz2021) studied the impact of climate change on wetlands in various regions of the world. The authors concluded that it causes negative impacts on the structure and function of these ecosystems, as well as the loss of biodiversity due to habitat loss, changes in water availability, and rising temperatures (Salimi et al. Reference Salimi, Almuktar and Scholz2021). In recent years, studies have been carried out on how climate change affects bird populations (Freeman et al. Reference Freeman, Sunnarborg and Peterson2019; Jirinec et al. Reference Jirinec, Burner, Amaral, Bierregard, Fernández-Arellano and Hernandéz-Palma2021 Molloy et al. Reference Molloy, Burbidge, Comer and Davis2020; Porfirio et al. Reference Porfirio, Harris, Stojanovic, Webb and Mackey2016; Saether et al. Reference Saether, Tufto, Engen, Jerstad, Rostad and Skåtan2000).

The effects of climate change on birds have been studied for over 50 years. For many species, both direct and indirect effects are observed, often due to changes in group behaviour (Saether et al. Reference Saether, Tufto, Engen, Jerstad, Rostad and Skåtan2000). Several bird species depend upon stability of specific periods of the year during which environmental conditions are more favourable for reproduction. As reproductive behaviours expend a significant amount of energy, the decision to reproduce is contingent upon the reliability and maintenance of these conditions. Consequently, the environment plays an important role in shaping fitness and survival rates of these species (Domingues Reference Domingues2012; Thomas et al. Reference Thomas, Cameron, Green, Bakkenes, Beaumont and Collingham2004).

In tropical regions, breeding tends to occur during spring and summer: food is abundant, temperatures are higher, and rains are frequent. Extreme climate events could provoke natural disasters that preclude reproduction, such as severe temperatures, changes in flowering and fruiting cycles, and higher rates of disease and parasitism in offspring (Marcelino et al. Reference Marcelino, Silva, Gameiro, Silva, Rego and Moreira2020).

The National Audubon Society’s new edition of its Audubon’s Birds and Climate Change Report warns that over two-thirds of North American birds are threatened by extinction due to global warming (NAS 2014). Studies show how climate change is affecting bird behaviour and interfering with reproduction (Bender et al. Reference Bender, Kissling, Böhning-Gaese, Hensen, Kühn and Nowak2019; Crick Reference Crick2004; Horton et al. Reference Horton, La Sorte, Sheldon, Lin, Winner and Bernstein2020; Marcelino et al. Reference Marcelino, Silva, Gameiro, Silva, Rego and Moreira2020; Radchuk et al. Reference Radchuk, Reed, Teplitsky, Van De Pol, Charmantier and Hassall2019; Sanz Reference Sanz, Rodriguez-Ferraro, Albornoz and Bertsch2003; Wegge and Rolstad Reference Wegge and Rolstad2017). It is important to note that most of the existing literature focuses on birds found in temperate habitats, illustrating how contemporary understanding of tropical birds is still poor and mostly based on assumptions taken from studies carried out on temperate birds.

Stephens et al. (Reference Stephens, Mason, Green, Gregory, Sauer and Alison2016) reported that shifts in bird population size due to climate change should be expected, as sensitive species will experience drastic population reductions while more tolerant species will adapt to, and benefit from anthropogenic changes to habitat.

Morphological responses

Jirinec et al. (Reference Jirinec, Burner, Amaral, Bierregard, Fernández-Arellano and Hernandéz-Palma2021) reviewed findings on over 77 species of Amazonian birds and found that climate change is affecting their morphology. Based on data collected since 1980 on over 15,000 non-migratory birds, researchers found that bird body shapes are becoming smaller as wingspan becomes larger (Jirinec et al. Reference Jirinec, Burner, Amaral, Bierregard, Fernández-Arellano and Hernandéz-Palma2021). This type of body shape, with a reduced body weight but larger wingspan, promotes efficiency in energy use, which may have been selected for in response to scarce resources in disturbed habitats (Jirinec et al. Reference Jirinec, Burner, Amaral, Bierregard, Fernández-Arellano and Hernandéz-Palma2021).

Beyond direct morphological changes, climate-driven shifts in avian traits also affect ecosystem functions, such as seed dispersal. For some plant species that depend on birds for seed dispersion, global warming will interfere with reproduction as birds carry seeds to unfavourable locations (Stokstad Reference Stokstad2022). Daru (Reference Daru2021) found that the majority of seeds within their study system were dispersed towards hotter regions in the south of Europe. This means fewer birds are carrying seeds to the north, where temperatures are more moderate, which may impact the plants’ reproductive success in a warming climate.

Among bird species, the Psittacidae family has representatives on almost every continent. However, habitat loss due to wildlife trafficking and hunting has led to the reduction of psittacine populations worldwide (Heinsohn et al. Reference Heinsohn, Buchanan and Joseph2018; Vergara-Tabares et al. Reference Vergara-Tabares, Codier, Landi, Olah and Nori2020). According to Vergara-Tabares et al. (Reference Vergara-Tabares, Codier, Landi, Olah and Nori2020) the global rate of habitat loss for Psittaciformes is 1.5% per year, which has reduced the populations of these animals by 20% in recent decades, becoming the main threat to their species. In Oceania, a significant number of psittacine species are classified as being under some degree of threat (Olah et al. Reference Olah, Theuerkauf, Legault, Gula, Stein and Butchart2018). According to Olah et al. (Reference Olah, Theuerkauf, Legault, Gula, Stein and Butchart2018) habitat loss represents a threat to 80% of the species, hunting and wildlife illegal trade represents a threat to 65% of the species, and predation by invasive species represents a threat to 40% of the species. Other negative impacts have been assessed, such as climate change, which reduces psittacine populations and jeopardises their conservation (Guedes 2009; Guedes et al. Reference Guedes, Fontoura, Tinoco, Mense, Trevisan and Lima2021; Joner et al. Reference Joner2015; Molloy et al. Reference Molloy, Burbidge, Comer and Davis2020; Ryding et al. Reference Ryding, Klaassen, Tattersall, Gardner and Symonds2021). In our research, we identified five main threats to psittacines, one of which is climate change (Table 1).

Table 1.

Main threats to psittacines from climate change

Molloy et al. (Reference Molloy, Burbidge, Comer and Davis2020) used climate change models to assess the impact on the Ground Parrot Pezoporus flaviventris population in Australia. The projections indicated a significant reduction in area of suitable habitat for the species due to rising temperatures and changes in habitat availability. The estimate was for a 70% reduction in the area occupied by Ground Parrot by the end of the century, which will impact the population viability of this species and increase the risk of extinction.

Heinsohn et al. (Reference Heinsohn, Buchanan and Joseph2018) pointed out that Psittaciformes have shown an ability to adapt to climate change, evidenced by changes in geographical distributions, breeding patterns, and feeding behaviours. However, the study highlighted some species that have been affected by climate change such as Imperial Amazon Amazona imperialis, a endemic species to Dominica Island, which is threatened, Yellow-billed Amazon Amazona collaria, endemic to Jamaica, Black-capped Parakeet Pyrrhura rupicola, found in the mountainous regions of South America, such as Colombia, Ecuador, and Peru, Orange-winged Amazon Amazona amazonica, found in the Amazon and parts of the Caribbean, and Red-tailed Amazon Amazona brasiliensis endemic to Brazil (Heinsohn et al. Reference Heinsohn, Buchanan and Joseph2018). All these species are being affected by climate change, which is leading to habitat loss, reducing food and reproductive resources (Heinsohn et al. Reference Heinsohn, Buchanan and Joseph2018).

Although habitat loss remains the dominant threat, morphological and physiological plasticity may modulate species-specific responses to climate-driven and land-use pressures. Joner (Reference Joner2015) evaluated the effects of several climate change scenarios on preserved areas in the Caatinga ecoregion and found that loss of suitable habitat would impact most species. Those that occupy more than one biome might be able to disperse to more favourable areas, so reducing their vulnerability to climate change. However, species that are endemic to the Caatinga ecoregion will not be able to escape habitat changes, rendering their survival a cause for concern.

This is the case for Lear’s Macaw Anodorhynchus leari, a species already suffering from poaching. Ryding et al. (Reference Ryding, Klaassen, Tattersall, Gardner and Symonds2021) reported that some species of Australian parrots have shown a 4–10% increase in mean beak size since 1871, as well as increases in leg and ear size. The morphological shifts in bill size observed in certain Psittacidae species represent adaptive plastic responses to mitigate the physiological impacts of rising global temperatures (Campbell-Tennant et al. Reference Campbell-Tennant, Gardner, Kearney and Symonds2015; Ryding et al. Reference Ryding, Klaassen, Tattersall, Gardner and Symonds2021).

Guedes et al. (Reference Guedes, Fontoura, Tinoco, Mense, Trevisan and Lima2021) reported that changes to the Pantanal ecosystem are jeopardising the reproductive success of the Hyacinth Macaw Anodorhynchus hyacinthinus population, thereby increasing vulnerability to extinction. Though the volume of annual precipitation has remained the same over the past 50 years, rain now arrives in short, intense storms; the amount of rain that would previously fall over 10 days now falls in one (Guedes et al. Reference Guedes, Fontoura, Tinoco, Mense, Trevisan and Lima2021). These deluges prevent water that pools inside nest cavities from draining, damaging eggs and harming offspring (Guedes et al. Reference Guedes, Fontoura, Tinoco, Mense, Trevisan and Lima2021). The same phenomenon was observed for Red-tailed Amazon in the state of Paraná. Papagaios do Brasil (2020) reported that high humidity influences egg-laying and number of offspring, demonstrating that higher temperatures have a relevant impact on species fitness.

Together, these studies indicated that morphological plasticity may function as a short-term buffering mechanism but is unlikely to ensure long-term population persistence under accelerating climate change.

Synergistic impacts with land use and fire

The wildfire regime in the Pantanal in 2020 severely compromised the demographic stability of Hyacinth Macaw, as retreat sites and nests suffered direct and indirect impacts from the fires. The fires decimated stands of the two palm tree species that make up the bulk of their diet, i.e. the acuri palm Scheelea phalerata and the bocaiuva palm Acrocomia aculeata. Subsequent months of high temperatures, low humidity, and scarce water availability followed the conflagrations. However, no burnt or scarred macaws were found at the Caiman Ecological Refuge, located in the Pantanal region of Mato Grosso do Sul and home to one of the largest Hyacinth Macaw breeding sites. The fires occurred during the breeding season, and about 50% of active breeding pairs suffered losses of offspring, eggs or nests (Guedes et al. Reference Guedes, Fontoura, Tinoco, Mense, Trevisan and Lima2021).

Fires also affected the population of Hyacinth Macaws in the northern Pantanal, Mato Grosso. According to Scherer-Neto et al. (Reference Scherer-Neto, Guedes and Toledo2019), for decades, the study site has been prone to fires and to the removal of trees used by these macaws as natural nesting sites, thereby negatively impacting the species’ reproductive success. Psittaciformes provide important ecosystem services for the maintenance of forests and ecological balance, mainly because they are seed dispersers (Blaco et al. Reference Blaco, Bravo, Pacífico, Chamorro, Speziale and Lambertucci2016; Heinsohn et al. Reference Heinsohn, Buchanan and Joseph2018; Tella et al. Reference Tella, Baños-Villalba, Hernández-Brito, Rojas, Pacífico and Díaz-Luque2015, Reference Tella, Blanco, Dénes and Hiraldo2019). With a generalist diet, Psittaciformes disperse seeds from countless plant species, contributing to plant diversity and structure, the maintenance and regeneration of forested areas, and biodiversity conservation (Blaco et al. Reference Blaco, Bravo, Pacífico, Chamorro, Speziale and Lambertucci2016; Tella et al. Reference Tella, Baños-Villalba, Hernández-Brito, Rojas, Pacífico and Díaz-Luque2015). According to Tella et al. (Reference Tella, Baños-Villalba, Hernández-Brito, Rojas, Pacífico and Díaz-Luque2015) there are Psittaciformes that disperse the seeds of up to 70 plant species and can defecate up to 8,000 seeds a day. They are also considered to be long-distance dispersers, with studies reporting seed dispersal up to 20 km from the mother plant (Tella et al. Reference Tella, Baños-Villalba, Hernández-Brito, Rojas, Pacífico and Díaz-Luque2015, Reference Tella, Blanco, Dénes and Hiraldo2019).

Implications for conservation policies

Martin et al. (Reference Martin, Perrin, Boyes, Abebe, Annorbah and Asamoah2014) studied large Psittaciformes from Africa and Madagascar and discussed the importance of basic research into patterns of feeding behaviour, reproduction, migrations, and ecological interactions for creating conservation measures for Psittaciformes species. According to Martin et al. (Reference Martin, Perrin, Boyes, Abebe, Annorbah and Asamoah2014) and Vergara-Tabares et al. (Reference Vergara-Tabares, Codier, Landi, Olah and Nori2020), effective conservation of this family requires mitigation actions not only to reduce habitat loss, but also other threats such as animal trafficking and hunting. To minimise the impact of climate change on the planet’s biodiversity and ecosystems, including the conservation of Psittaciformes, the following actions should be taken: the implementation of ecological corridors, the creation of protected areas, the restoration of degraded habitats, the implementation of sustainable agricultural practices, the reduction of greenhouse gases, and involvement of the community (Dirzo et al. Reference Dirzo, Young, Galetti, Ceballos and Isaac2014; Martin et al. Reference Martin, Perrin, Boyes, Abebe, Annorbah and Asamoah2014; Sala et al. Reference Sala, Chapin and Armesto2000; Salimi et al. Reference Salimi, Almuktar and Scholz2021; Vergara-Tabares et al. Reference Vergara-Tabares, Codier, Landi, Olah and Nori2020). According to Brooker et al. (Reference Brooker, Young and Watt2007), Molloy et al. (Reference Molloy, Burbidge, Comer and Davis2020), and Vergara-Tabares et al. (Reference Vergara-Tabares, Codier, Landi, Olah and Nori2020), the involvement of civil society, including local communities, non-governmental organisations (NGOs), and the private sector, is essential for the success of biodiversity conservation and climate change mitigation policies.

As global climate change continues, conservation and population management strategies are becoming increasingly necessary to conserve the planet’s biodiversity, while creating mitigation measures to halt these changes. To this end, detailed studies on the impacts of climate change on the populations not only of birds but also other species of animals, as well as plants and their ecosystems, are essential. This includes studies on the range, behaviour, reproduction, and plasticity of these organisms in the face of these changes, as well as priority areas for conservation.

Although research shows an increase in the impacts of climate change on psittacines, there are still gaps in our knowledge about each species’ ability to adapt to these changes. It is important to remember that long-term monitoring is essential to understanding how climate change associated with habitat loss – whether due to deforestation or fires, animal trafficking, and hunting impact the morphology and behaviour of this highly threatened group. It is suggested that new research should be conducted focusing on distribution modelling and evaluating physiological and morphological changes in scenarios of increasing temperature, as well as collaborative monitoring research in underrepresented areas, such as tropical regions. It is essential to strengthen interdisciplinary research networks and integrate local communities in conservation planning and implementation so that the mitigation strategies developed are effective for psittacine species and the ecosystems in which they live.