Here is a term paper on the ‘Impacts of Climate Change on Birds’ for class 9, 10, 11 and 12. Find paragraphs, long and short term papers on the ‘Impacts of Climate Change on Birds’ especially written for school and college students.
Climate Change and Birds
Term Paper Contents:
- Term Paper on the Introduction to Climate Change
- Term Paper on the Altitudinal Shift and Distribution Pattern of Birds
- Term Paper on the Alteration and Loss of Bird Habitat
- Term Paper on the Increase in Disease Prevalence in Avian Communities
- Term Paper on the Change in Migration Phenology of Birds
- Term Paper on the Impact of Climate Change on Breeding Phenology
- Term Paper on the Impact of Climate Change Leading to Population Change
- Term Paper on the Remarks on Impacts of Climate Change on Birds
Term Paper # 1. Introduction to Climate Change:
The impact of climate change on the avifaunal community throughout the globe has been best studied. Birds are considered as good indicators of environmental change, as they are easy to identify, placed high in the food chain, thus they often reflect the events and processes further down the chain, relatively well-studied and are often with pre-existing baseline data. Therefore, changes in bird populations have been proposed to be considered as an indicator to study the impact of climate change.
Evidences indicate that the climate change influences the distribution, phenologic patterns as well as breeding success of many bird species. Many bird species are extending their geographical ranges northwards, while some migratory birds arrive earlier on their breeding grounds, start breeding earlier or even migrate to their wintering grounds later.
Term Paper # 2. Altitudinal Shift and Distribution Pattern of Birds:
Several studies indicate that birds, as well as other flora and fauna, are shifting their ranges towards the pole or to higher altitudes in tropical mountains in response to climate change. Root and Schneider (1993; 2003) found strong statistical correlations between six large scale environmental factors, mainly climatic variables and the distribution and abundance of a majority of 148 wintering land birds of North America. Generally, range shifts are likely to have the greatest impacts on the species occupying tundra, arctic and montane habitats.
The extents of these habitats are likely to be seriously reduced under warmer conditions (IPCC, 2001), with a consequent effect on the population of birds (and other wildlife) inhabiting those habitats. European birds are expected to undergo range shifts causing a net decrease in neo-tropical migrant bird species in every region of USA, including boundary shifts of more than 1,000 km.
It is important to note that range contractions are expected to be more frequent than range expansions. Studies indicate that future range shifts due to global warming are expected to 29 to 30 per cent net decline in the number of bird species in the eastern Midwest and Great Lakes regions respectively. Besides, their new climatically suitable ranges may also be unsuitable for their survival due to fragmented landscapes caused by unscientific human land use.
Moreover, presently most of the areas with rich avifaunal diversity have been notified as protected areas. Shift in distribution range, as a consequence of global warming, may force these birds to live into some unprotected areas leading to an even greater challenge for conservation. In Europe, the endangered Spanish imperial eagle, currently found mainly in natural reserves and parks, is expected to lose its entire current range.
Island and mountain birds may perish with the alteration of climate pattern and rise in temperature, as they are confined to increasingly smaller patches of habitat. With high global warming scenario, it has been projected that there will be 99 per cent shrink in the Scottish highland habitat of the Capercaillie (Tetrao urogallus), the world’s largest grouse, by 2050 virtually eliminating UK habitat for this bird.
Range shifts and changes in distribution pattern will finally lead to a change in the species composition of the natural communities as because the response of each constituent species to climate change will be unique. Hence, birds living in such altered natural communities may often come into contact with different prey species, competitors, parasites and predators.
Study of an entire ecological community in Mexico including 1,179 bird species, predicted greater than 40 per cent turnover in some local ecological communities by 2055 suggesting severe ‘ecological perturbations’, as many species are supposed to disappear or displaced by invader species.
Term Paper # 3. Alteration and Loss of Bird Habitat:
Global warming and climate change will lead to a change in the vegetation pattern and cause subsequent alteration of habitat. Changes in vegetation pattern will be most extreme for the Tundra areas. An overall 40-57 per cent loss of current tundra habitat has been estimated which, in turn, will have adverse impacts on the population of arctic birds. Shrink of tundra habitat will particularly affect birds like geese and sandpipers as they breed exclusively in these regions.
Birds in the antarctic region are affected as well. Population dynamics of several species of penguins inhabiting Antarctic Peninsula are seriously affected with warming and disappearance of the sea ice cover. Several studies indicate that crucial bird habitats, especially for the wetland birds, are reducing with the shrinking and shifting of wetlands as a result of global warming.
Populations of Siberian crane (Grus leucogeranus) consist of 3,000 individuals throughout the globe and have already shown its vulnerabilities to climate change. This bird was once a regular winter visitor in India, but no more visits its wintering grounds in this region.
Sea level rise will also impact a number of coastal ecosystems. Permanent inundation of coastal zones will pose a serious threat to the estuarine mudflats and salt marshes with severe implications for both wintering and breeding waterfowl and wader species. When the sea level rises, the marsh vegetation tends to move upward and inland. However, ridges along the coastline often prevent this movement leading to coastal squeeze and loss of marsh area.
Estuarine mudflats also represent important feeding sites for wintering waders. The shape of these estuaries may also change with the increasing sea-level, which will further influence the nature of the sediment thereby altering the species composition and density of the invertebrate populations on which the waders feed.
With the advancement of sea, the sediment will become sandier leading to the decline in the densities of waders that prefer muddy estuaries, like redshank and dunlin. However, both density and number of the species that prefer sandy estuaries, such as oystercatcher, are predicted to increase.
Mangroves are highly adapted trees that thrive in the intertidal waters of the tropical region and are treasure house of rich avian diversity. Encroaching sea water may also threaten the survival of several mangrove species.
Term Paper # 4. Increase in Disease Prevalence in Avian Communities:
A number of authors have raised the possibility that global warming might have played a crucial role in the recent range expansions and outbreaks of vector-borne diseases. Climate change has the potential to alter the exposure of several bird populations to vector-borne diseases by changing the distribution of geo-climatic conditions that are suitable for the vectors and disease pathogens.
An increase in global temperature will result in an expansion of warm temperature regimes into higher altitudes and latitudes. Any associated changes in rainfall in tropical and subtropical zones will also render habitats more or less suitable for vectors.
These changes would make birds in the temperate environments more receptive to many tropical vector-borne diseases while having less negative effects on tropical environments. Besides, extreme climatic events are also reported to have major effects on the transmission rates of vector-borne diseases and the climate change is expected to increase the frequency of such events.
There are increasing evidences that warmer temperatures are thought to favour the spread of various infectious diseases and parasites and can influence the dynamics of bird populations through increased mortality and thus can limit population growth in some cases. Rate of reproduction of pathogens or the distribution of vectors carrying these pathogens are altered with the change in climate parameters.
Besides, reduced precipitation and greater drought is expected in some regions and this could compel many species of birds to accumulate around limited water resources, increasing the risk of exposure to the potential pathogens and their quick transmission among the closely associated individuals (BTO, 2002). According to Epstein (2001), warm winters and spring droughts led to the spread of West Nile Virus through avian populations in Europe and North America.
Benning et al. (2002) suggested that the increase and invasion of mosquitoes carrying malarial pathogens due to temperature rise might lead to the extinction of several species of Hawaii’s honeycreepers. However, the actual extent of the impact of climate change on bird population could not be forecasted as relatively little is known about epidemiology of many bird-parasites.
Term Paper # 5. Change in Migration Phenology of Birds:
Migratory birds may particularly be vulnerable to the impact of climate change as they use separate habitats, often geographically distant, as their wintering and breeding grounds and changes in any one of the sites during their life cycle may have serious impacts on their survival and population dynamics.
Climate induced changes in habitat are likely to have impacts on staging, stopover ecology and fuelling in migratory birds as well. This is the area of study for which there is the strongest evidence of the impact of climate change on birds.
i. Spring Migration:
The timing of arrival on breeding grounds is very much crucial for the migratory birds, especially as it has to be synchronized with the availability of prey. With the changing climate, time of arrival of migratory avifauna to the breeding site (spring migration) is changing as well. As a consequence of this ‘phenological mismatch’, many migratory species are unable to breed successfully because their arrival time no longer coincides with peak food availability.
In Netherlands, this mismatch has led to the decline of up to 90 per cent in some populations of pied flycatchers over the past two decades. Observations made at several point locations, as well as over broad areas like English counties show general trends towards earlier spring arrivals for many species. One analysis of 64 studies revealed that birds had advanced timing for such spring migration arrival to their respective breeding site at an average rate of 6.6 days per decade.
Similar advances in arrival dates of spring migrants have been seen in Europe and North America. Changes in the timing of arrival seem to be greater among short-distance migrants, than long-distance migrants. In Europe, some birds (which normally used to migrate) have even stopped migrating altogether. Long-distance migratory birds are facing a greater climate change threat than the resident birds, as they are often unable to adjust their migratory journeys with the peak food availability.
The arrival dates of the long-distance migrants are relatively unchanged and the time of peak insect availability has advanced. As a consequence, many long-distance migratory birds are nesting more quickly after their spring arrival in Europe. Many other long-distance migrants are unable to nest and breed sufficiently quickly to match nestling’s food demands with peak insect supplies.
Some species of long-distance migrants in Europe and North America are already showing signs of decline. Of 119 long-distance migrants studied in Europe, 54 per cent have already shown a sustained, often severe, decline from 1970 to 2000, with climate change implicated as a major contributing factor.
ii. Winter Migration:
Studies of migratory birds indicating later departure from their breeding grounds and earlier arrival on the wintering grounds are scanty and more scattered. Sparks and Mason (2001) observed that nine species displayed trends towards progressively later departures for the wintering grounds since the 1950s, whereas only one species was leaving the UK at a significantly earlier date than before.
Studies on the autumn passage of willow warblers (Phylloscopus trochilus) at Dungeness Bird Observatory in Kent revealed that departure dates were on average 5-10 days later over the period 1994-2000 than they had been in between 1962-1968.
There are few evidences suggesting that short-distance winter migrants in UK, such as merlin (Falco columbarius) and hen harrier (Circus cyaneus), are appearing on the wintering grounds earlier. However, this trend is less consistent across species as there are many other short-distance migrants displaying no advancement at all.
iii. Effect on Migratory Routes and Stopover Sites:
Climate induced changes in habitat are likely to have impacts on staging, stopover ecology and fuelling in migratory birds. Migratory fuelling generally occurs before crossing a large ecological barrier, such as a large expanse of desert, water and High Mountains.
For example, the garden warbler (Sylvia borin) weighs 16-18g in the breeding and wintering seasons and increases its body mass to 37g before crossing the Sahara desert by depositing large amount of fat within the body tissues. Appropriate time and amount of deposition of fat is crucial for successful completion of their migratory journeys. Therefore, any mismatch in this timing may even threaten their survival.
Stopover sites are of special significance for successful migration of birds as they use them to rest and feed during their migratory journeys. Besides, weather conditions en route are also known to affect an individual’s ability to migrate.
Changes in wind direction and velocity could also have a major impact on the physical condition of the migrants. Therefore, loss or destruction of stopover sites and changes in several other climatic parameters both in the stopover sites as well as in the migratory pathway may compromise the ability of the migrants to complete their migratory journeys.
Term Paper # 6. Impact of Climate Change on Breeding Phenology:
Except a few opportunistic breeders, many bird species use temperature as direct cue to time their breeding. The changing climatic conditions may also lead to the alteration in the availability of food resources, which, in turn, affects the breeding success of both migratory and resident species of avifauna. Studies on the El Nino reveal that periodic warming alters oceanic currents along the west coast of the America, leading to a crash in fish abundance and catastrophic breeding failure or even adult mortality among seabirds in the Pacific.
A similar study between 1950 and 2000 on fulmars (Fulmarus glacialis) in Orkney, located off the north coast in Scotland, revealed that hatching and fledging success were related to the North Atlantic Oscillations (NAO), which potentially influence the abundance of their crustacean and fish food supplies.
In north Scotland, internationally important populations of sea birds have suffered massive breeding failures, which appear to be due to the unavailability of food as a result of the collapse of an entire food web. The warmer seawaters caused a serious decline in the number of plankton subsequently leading to a crash in the fish population, which in turn affected the sea birds.
Analyzing the breeding data from the British Trust for Ornithology’s Nest Record Scheme (NRS) it has been found that 51 species show a trend towards laying earlier. Dunn and Winkler (1999) analysed 3450 nest records from the North American nest record schemes between 1959 and 1991 and found that the mean lay date of tree swallow (Tachycineta bicolor) had shifted an average of 9 days earlier which is mainly attributed to the change in air temperature.
Further analysis of nesting data for 65 species of birds in the northern latitudes of the United Kingdom over the period 1971-1995, revealed that laying dates were significantly advanced, on average by 8.8 days, in 20 species including waders, resident and migrant insectivores, corvids and seed-eaters. Crick and Sparks (1999) found that laying dates were significantly related to either spring temperatures or to spring rainfall.
They also calculated that by the year 1995, 53 per cent of species in their study showed a significant advancement in their laying date and they predicted that the average laying dates will be earlier for 75 per cent of species in UK by the year 2080. Hence, there are good evidences to indicate that change in egg-laying date are driven by changes in the climate. Although earlier laying appears to be advantageous as it permits a longer breeding season, but climate change actually lead to a lack of synchrony between the peak nestling food requirements and peak prey availability.
This phenological dysfunction could potentially result in reduced breeding success as many new-born offspring might be deprived of sufficient nourishment due to poor prey availability, which in turn might give rise to weaker individuals and, in worse cases, might even lead to a population crash.
However, it is interesting to note that ambient temperatures during the laying period have been found to positively influence the clutch size of a number of passerine species, including the migratory pied flycatcher (Ficedula hypoleuca) and common redstart (Phoenicurus phoenicurus) and increased clutch sizes have also been reported to be positively correlated to the warmer temperatures and earlier laying dates.
Few studies suggested that adverse climatic conditions, especially during the onset of the breeding season, might also influence adult birds. Wet summers are associated with poor breeding success for migratory raptors. It has been documented that breeding performance of peregrine falcon (Falco peregrinus) and merlin (Falco columbarius), that hunt other bird species on the wing, are adversely affected as heavy rain reduces their visibility, as well as, minimize the activity levels of their avian prey species.
Term Paper # 7. Impact of Climate Change Leading to Population Change:
The size of all populations is essentially controlled, at a fundamental level, through the balance of several demographic rates, i.e. natality, mortality and migration. Significant impact of climate change on both productivity and survival of many bird species have been well documented and the relative magnitudes of these impacts determine the overall change in population size.
Number of studies indicate that the impact of local weather, mostly temperature and precipitation variables, largely influence the population size of many species of avifauna. Extreme weather events can have catastrophic effects on bird populations. Increased storm frequencies, as a consequence of climate change, affect the productivity of species that nest in low-lying coastal areas, particularly on tropical islands.
It may also affect the ability of birds to complete their migratory journeys. Severe storms can also have a direct impact on an individual’s survival. Lens and Dhondt (1992) reported the death of 62 per cent of their study population of crested tit (Parus cristatus) after a severe storm in Belgium. The effect of tornadoes and hurricanes may be similarly devastating and the seabirds are particularly vulnerable to those severe adverse conditions, which may result in the mortality of large number of individuals.
Migratory species passing through hurricane belts, in areas such as the Caribbean, often face serious threat due to adverse climatic conditions during their migratory journeys. With the changing climatic conditions, the intensity and frequencies of these storms are supposed to increase making the scenario even worse for those seabirds and migratory species. Extreme climates not only lead to the increased mortality of individuals, but they also influence the abundance and availability of the food supply.
For example, extended periods of frost or snow cover may prevent ground-feeding birds from foraging, leading to increased rates of mortality and hence a reduction in population size. Survival rates of many passerines that spend the winter in Britain are known to be related to winter weather conditions. About 65 days gap between the date of the first robin sighting and the first date of bare ground at the snow measuring station has been reported, which is 18 days longer than in 1981.
As a result, the birds are forced to wait longer for the snow to melt before they can feed facing a greater risk of starvation. In UK, annual census datasets of grey heron (Ardea cinerea) since 1928 show significant weather driven population crashes due to poor survival in severe winters. Climate induced shift in their distribution is leading to a decline in the numbers of many species of Britain’s wader populations.
Similarly, climatic conditions may also influence prey availability for seabirds, which not only affects their productivity, but may also impact on their survival. Population of emperor penguins (Aptenodytes forsteri) in Terre Adelie, Antarctica decreased during a relatively warm period as the increased sea surface temperatures led to poor krill (Euphausia superba) production, resulting in reduced populations of fish and squid (which prey on the krill) and hence poorer foraging success for the penguins.
Once survival recovered, population of these penguins stabilized at a new lower level. Similar 94 per cent decline in rockhopper penguins (Eudyptes chrysocome) population on Campbell Island since the early 1940s and 90 per cent decline in the numbers of sooty shearwaters (Puffinus griseus) off the west coast of North America in the non-breeding season since 1987 were reported to be associated with rises in sea-surface temperature and subsequent declines in the availability of their prey species.
On the contrary, the low temperatures and high rainfall in winter also adversely affect the foraging success of many migratory shorebirds.
Term Paper # 8. Remarks on the Impacts of Climate Change on Birds:
It is evident that the global warming and climate change is seriously affecting many aspects of avifauna and there are many reasons to be concerned about the plight of several species of birds induced by climate change. Birds play an important role in nature, pollinating plants, dispersing seeds and eating insects.
Several species of warblers are thought to be one of the major bio-control agents in parts of the Great Lakes and Rocky Mountain regions and are responsible for eating up to 84 per cent of spruce budworm larvae, mountain pine beetles, other pests possibly controlling insect outbreaks and play a vital role in the protection of the commercially and ecologically important forests in these regions.
Some birds are critical to the reproduction of plants. The long-distance migrants, for example rufous hummingbird (Selasphorus rufus), is the primary pollinator for the wild blueberry in southeast Alaska and helps benefit the entire ecosystem as many other wildlife species in the region depend on the blueberry for food. Besides playing vital ecological role, they also serve as one of the major indicator of the ecosystem functioning.
Species that are unable to respond to climate change through phenotypic and/or genotypic adaptability maybe most vulnerable to climate change and species with poor dispersal ability may not be able to adapt with the changing climate parameters. Rapid changes in the environment are likely to favour generalist/ adaptable species and be detrimental to highly specialized species adapted to a specific ecological niche.
Survival of birds with small population will be threatened if the climate becomes more variable, as predicted. From the review of several literatures it is evident that several bird populations may be drastically reduced by extreme climatic events and an increase in the frequency of such events may altogether affect their viability.
Climate change may lead to the alteration in the bird habitats by changing the time and abundance of their food supplies and other resources leading to the altitudinal shift in distribution and abundance, as well as, change in the migration and breeding phenology of many species.
Besides, inundation of most of the low-lying and coastal areas due to rise of sea-level will lead to the loss of many natural habitats which in turn will lead to the unavailability of suitable habitat for a good number of coastal species. With the decline and change in the rainfall pattern, the floral composition of several region of the globe will be altered, which subsequently, will alter the faunal community dependent on it.
Rainfall will also influence the crop pattern and agricultural biodiversity. Large-scale changes in agriculture/including crop types and pesticide usage (in response to changing pest populations)/ will also threaten many bird species that live in such agricultural lands. Species range expansion or contraction in response to climate change/may lead to changes in the level of competition and predation. However, information on the impact of climate change on Indian birds is very scanty.
More ornithological researches, involving several aspects of birds found in this Indian subcontinent, are essential to understand the impact of climate change on the population dynamics, distribution and survival of individual avifaunal species in this region.
Long-term monitoring schemes and databases on population and nests of several bird species can help to identify several new and unforeseen impacts of climate change. Another important area that needs to be addressed is the potential detrimental impacts of the invasive and alien species on the survival of the native flora and fauna under changed environmental conditions.
Moreover, the responses of avifaunal species to global warming are early signals of the wider threat not only to the wildlife and ecosystems, but also to the very existence of human civilization. The shift in climate regime has already started to influence the epidemiology of several vector-borne diseases in human beings as well. India is surrounded by oceans on its three sides.
An intensification of tropical and subtropical cyclones, sea level rise and subsequent flooding in coastal regions will not only lead to habitat unavailability and population decline of many coastal birds, but will affect millions of people living in coastal villages as well. In India, it is estimated that about seven million people would be displaced with one-meter sea level rise. More than 1,000 people died and there was huge property loss as severe cyclone hit Andhra Pradesh in 1996.
Therefore, priority need to be given to the researches on climate change, so that proper adaptation strategy for future could be designed well in advance based on a robust scientific database. The impact and consequences of global warming and climate change is alarming and it is time to act both at local to global level to save many species from the imminent extinction in near future.