One recent example is the decline of ash trees (Fraxinus spp.), both in North America due to the introduction of Emerald Ash Borer and in Europe due to the emerging disease caused by the ascomycete Hymenoscyphus pseudoalbidus. Mortality levels are high in both cases and the spread has been rapid. You can find maps of the extent of the problem in the two following papers

Geoffrey H. Donovan, PhD, David T. Butry, Yvonne L. Michael, Jeffrey P. Prestemon, Andrew M. Liebhold, Demetrios Gatziolis & Megan Y. Mao (2013) The relationship between trees and human health. Evidence from the spread of the Emerald Ash Borer. American Journal of Preventive Medicine 44, 2: 139-145

http://dx.doi.org/10.1016/j.amepre.2012.09.066

Marco Pautasso, Gregor Aas, Valentin Queloz & Ottmar Holdenrieder (2013)

European ash (Fraxinus excelsior) dieback – a conservation biology challenge.

Biological Conservation 158: 37–49

http://dx.doi.org/10.1016/j.biocon.2012.08.026

Which of the widely distributed frog species are threatened by extinction?

The Rusty Blackbird (Euphagus carolinus) was a very common species that has rapidly declined in the past 40 years to the level of vulnerable species according to the IUCN. Unfortunately, we are still not able to determine the cause of this decline although habitat loss is likely.

When was the American crocodile "very common species"?

Gyps bengalensis, Gyps indicus and Gyps tenuirostris in South Asia due to secondary poisoning with diclofenac. Gyps bengalensis, considered the most abundant large bird of prey in the mid-1980s, declines by >90% over a 10 year period. All three species are now considered Critically Endangered and functionally extinct.

The European rabbit or common rabbit (Oryctolagus cuniculus) is a species of rabbit native to southwestern Europe (Spain and Portugal) and northwest Africa (Morocco and Algeria). It has been widely introduced elsewhere, often with devastating effects on local biodiversity.

However, its decline in its native range (caused by the diseases myxomatosis and rabbit calicivirus, as well as overhunting and habitat loss), has caused the decline of its highly dependent predators, the Iberian lynx and the Spanish Imperial eagle.

Yep - the vulture declines Andrew notes are probably the most striking recent examples of catastrophic population collapse in birds

I wonder what the definition is of 'rapid', but it seems to me that the decline of the passenger pigeon and American bison were steep and relatively quick (i.e., within the lifetime of a person). Within the span of a few decades, passenger pigeons went from one of the most abundant birds on the planet (if not THE most abundant) to extinct. Bison followed a similar course, for similar reasons, but thankfully stopped short of extinction.

In Spain, Kulh's pipistrelle (Pipistrellus kuhlii) was a common bat species in the southern of Spain. However, the population has declined in last years.

Although, not as 'rapid' as the decline of vultures in S Asia, House sparrow (Passer domesticus) is probably going the same way. Once widespread and very common, it is rapidly disappearing from many areas.

American eel, http://www.mnr.gov.on.ca/stdprodconsume/groups/lr/@mnr/@species/documents/document/stdprod_075572.pdf

Ligumia nasuta (freshwater mussel) "The Eastern Pondmussel was one of the

most common species of freshwater mussel in the lower Great Lakes, numbering in the billions, prior to the invasion of the zebra mussel (Dreissena polymorpha ) in the late 1980s. It has likely been extirpated from nearly all previously inhabited areas in Canada due to the impacts of zebra mussels." http://publications.gc.ca/collections/collection_2007/ec/CW69-14-528-2007E.pdf

Leatherback sea turtles, especially in the Pacific, (actually, pretty much any sea turtle), Atlantic Cod, most Asian river turtles, Several whale species, Steller's Sea Cows, Northern Elephant Seals, Sea Otters, Sea Mink, Tigers, many other examples due to hunting pressure.

http://news.sciencemag.org/sciencenow/2011/11/ladybugs-changed-color-in-respon.html Refers to a Dutch long-term evolution study that ended because of the disappearance of the study species (two-spotted ladybug) due to invasive competitor.

Saiga tatarica http://en.wikipedia.org/wiki/Saiga_antelope

The intertidal blue mud shrimp, Upogebia pugettensis, native to north east Pacific estuary mudflats has declined precipitously since the 1980s in association with a parasitic isopod, Orthione griffenis that effectively castrates females by blood loss.

https://dl.dropbox.com/u/48637718/Chapman%20et%20al.%202012.pdf

Ursus maritimus (polar bear) and many other polar animals, Callorhinus ursinus (northern fur seal)

atlantic cod, european sparrows (in some regions), turtle doves, certain warbler species that breed in Europe (due to expansion of sahel region affecting migration?), certain species of bumble/solitary bees were common but have all declined significantly in last 50-100 years.

Hi John, I am sending you a website from the London Zoo. The 'Edge of Existence' program will give you good, sound scientific information not only about species in rapid decline but those which are evolutionarily distinct. I assume that when you say 'rapid decline' you are referring to not only populations but to gene pools as well. Do have a look at this. It is a treasure trove of info.

http://www.edgeofexistence.org/

The common reed (Phragmites australis). Do you know the reed die-back syndrome in Europe?

http://www.sciencedirect.com/science/article/pii/S0304377097000600

http://dx.doi.org/10.1016/j.aquabot.2012.07.005

https://www.researchgate.net/publication/227854911_Correlation_Between_Sexual_Reproduction_in_Phragmites_australis_and_Die-back_Syndrome?ev=prf_pub

Article Correlation Between Sexual Reproduction in Phragmites austra...

There are plenty of less recent examples-

Passenger pigeons of course.

Many Australian mammals crashed from being considered agricultural pests in 'plague' proportions to extinction over less than a decade at various times between 1860 and 1910, for example bettongs and small wallabies (Short, J., 1998. The extinction of rat-kangaroos (Marsupialia: Potoroidae) in New South Wales, Australia. Biological Conservation 86, 365-377). The likely cause of most of these is probably the invasion of the red fox. There are also many island species and freshwater lake species that went very rapidly extinct from a starting point of local abundance due to invasive predators. Some birds were extirpated by brown tree snakes on Guam over about five years. The IUCN red list species accounts of extinct species (online) will have lots of these examples.

Many species of cetaceans such as right, blue, humpback, bowhead and gray whales were hunted to the point of being endangered and a few of them (north Pacific right whale and north Atlantic right whale) have never recovered while others such as the eastern north Pacific gray whale populations have recovered to pre-whaling levels

"right, blue, humpback, bowhead and gray whales were hunted"

it was a way for people from USA and Japan to make profit

p.s. if increasing in number of those species would have been profitable, than probably in the present there would have been whale-farms under the tables from the Oval Room of the White House and on the top of Fuji volcano...

in India vulture population decreased of about 90% in just a decade time period from 1990 to 2000. its mainly due to an anti inflammatory drug used to treat cattle. presently there is a bit recovery of the vulture population thanks to extensive conservation projects and very strict prohibition on use and sale of the drug.

another example is the disappearance of indigenous cattle breed varieties in south India specially in Karnataka state where very few high milch breeds of exotic cattle hi-breeds taken over.

eg:- mangalore gidda (local name) a dwarf cattle breed in the western ghats region which was a dual purpose breed.

"disappearance of indigenous cattle breed varieties"

not to mention the fact that one of my dogs died in 1991...

The best known examples have allready been mentioned (passenger pigeon, wales) but there was also the American bison. Recently in Europe one of the mammal species that is declining most rapidly is the Garden dormouse (Eliomys quercinus) with a assumed 50% loss of range during the last three decades.

Johannes Lang: "(Eliomys quercinus) with a assumed 50% loss of range during the last three decades"

50% in Western part or Europe or where?

Based on my personal direct experience (Sicily and southern Italy) [in order of most evident impact] firefly, hedgehog, badger, weasel.

Thus species in decline may be grouped according to causes: 1) environment change (polar flora and fauna); hunting and fishing (including also sharks, snakes and other dangered animals); inner genetic and population level causes; invasive new-comers into the niches of aborigens, infections and epidemics. Something else?

"Something else?"

road-killing

I think it is interesting to consider the life-history characteristics that make possible rapid declines. In the case of Myotis lucifugus in eastern North America, such a spectacular decline in only a few short years represents a collision course between the novel pathogen and the evolutionarily successful strategy of prolonged torpor. The slow life histories of bats, particularly those that hibernate at higher latitudes, are very important to the dynamic of rapid decline - the associated low fecundity means that it will take a very long time for the species to "dig out of the hole". There must be similar kinds of "collision courses" involved in the other examples?

The Cantabrian Capercaillie (Tetrao urogallus subsp. cantabricus) population has been reduced in a 90% in the last ten years, probably due to a sinergic effect of different factors such as habitat destruction and fragmentation, competition with cattle and wild herbivores (e.g. red deer, whose population has grown considerably), very high chick mortality, poaching, etc.

Some examples:

Bañuelos MJ, Quevedo M, Obeso JR. 2008. Habitat partitioning in endangered Cantabrian capercaillie Tetrao urogallus cantabricus. Journal of Ornithology 149: 245-252

Storch I, Bañuelos MJ, Fernández-Gil A, Obeso JR, Quevedo M, Rodríguez-Muñoz R. 2006. Subspecies Cantabrian capercaillie Tetrao urogallus cantabricus endangered according to IUCN criteria. Journal of Ornithology 147 (4): 653-655

Quevedo M, Bañuelos MJ and Obeso JR. 2006. The decline of Cantabrian capercaillie: how much does habitat configuration matter? Biological Conservation 127: 190-200

You stated that you were aware of three bat species threatened with extinction, among those species are you considering various species affected by the "white nose syndrome" in North America. Approximately 80% of North American species have suffered a drastic decline since 2007. This fungal infection may result in the extinction of North American bat species because it is fast acting and little information about the syndrome is known. I hope this helps and good luck with your research.

Source: http://www.nwhc.usgs.gov/disease_information/white-nose_syndrome/

Hi, in Poland we have few examples of species rapidly decline in last 30-15 years.

Tetrao tetrix – earlier most common in forest and swampy area, game (hunting) species till half of 90s, today left only about 2000 individuals and still declining, mostly because of changes in forests and drainage of marshes and bogs.

Tetrao urogallus – game species till half of 90s, left less than 500 individuals, mostly because of changes in old forests.

Lepus europaeus, Perdix perdix – formerly one of most common game species, today we see a sharp decline in densities. Lepus – earlier densities often was over 50-100 per 100/ha, today in most cases are less than 5 individuals /100 ha. Most important causes - changes in the environment, an increase in the number of predators.

Astacus astacus – rapidly declines, endangered because of ill (Aphanomyces astaci) and competition with invasive species e.g. Orconectes limosus.

Almost all amphibians and reptiles still declines.

But we have a few examples of species who are almost extinct but today are plentiful.

Best examples are beaver and moose. After second World War only a dozen left – but today we have almost 7500 moose's and 40000-50000 beavers.

Dear colleagues

the problem of this question is the definition of "rapid". Is the decline of a common species over decades rapid or not? My example, that is based on evidence and experience is the decline of the still common but less abundant key species of european grasslands, arrhenatherum elatius. This grass species was so regularly distributed and abundant that it even served as the name-giving species in the phytosociological system of syntaxa for the highest rank (class): arrhenatheretea. Today, the species still occurrs but is increasingly replaced by other perennial grasses such as alopecurus pratensis. Such kind of dominance shifts are rapid in evolutionary and ecological terms and they are really influential for the functioning of ecosystems over large scales, but they are hardly remarked at all.

Some of the examples mentioned are of once widespread species that declined rapidly. However, from an evoliotionary perspective there may be a hidden genetic loss that goes undetected. I know for, example, that some Scilla species (monocot plants in KwaZulu Natal, South Africa), although widespread and declining across their range from medicinal harvesting, have had a catastrophic genetic loss in a small part of their range where more than 80% of their genetic diversity resides. So I think the spatial distribution of genetic diversity within a species is also imporrtant and that the problem may be more widespread if we just adopt a quatitative approach (numbers of individuals). Equally important to the discussion is the question of genetic diversity within a taxon and its distribtution.

American chestnut, Passenger pigeon, Bombus occidentalis and related bumblebee species in NA, several perennial bunch grasses once widespread in California,

The Nassau grouper, Epinephelus striatus, was common in the Western Caribbean. However, its breeding habits (reproductive aggregations, numbering hundreds or, according to some accounts, thousands of individuals, in depths accesible to spear-fishing) made it so vulnerable that now it is threatened. See e.g. Aguilar-Perera 2006, Marine Ecology Progress Series 327: 289–296.

There are several examples of exploited species (e.g. high value targets of fishing or whaling industries) that have declined rapidly. Steller's sea cow is a particularly striking example - discovered in 1741, extinct by 1768 (27 years; on the order of one generation time).

Actually, as to Jenae's comment above, far fewer than 80% of North American bat species have been affected by white-nose syndrome, and only a few species so far are thought to have really suffered drastic declines. But as to the point of the discussion, I think Myotis lucifugus, the little brown bat, is a spectacular example of this phenomenon of formerly abundant and widespread species rapidly declining as a result of novel stressors.

Another theme to explore in this context is the idea of foundation species, such as the whitebark pine in high-elevation North American mountain ranges that again, due to novel pathogens (white pine blister rust) introduced from afar, have shown precipitous declines. Accelerated warming and the impacts from pine beetle outbreaks promise cumulative impacts with the initial loss from rust. Cascading ecological effects, such as the loss of seed dispersers like Clark's nutcrackers from heavily affected areas, follow.

White-rumped Vulture (Gyps bengalensis) and Indian Vulture (Gyps indicus) both are Critically Endangered with Decreasing Population Trend.

The population of Gyps vultures has declined in South Asian region from 80 to 95 % in the recent years (Khan and Murn, 2011). White-rumped Vulture (Gyps bengalensis) was considered one of the most abundant large birds of prey in the world. In the late 1990s, the Indian populations of White-rumped Vulture (Gyps bengalensis) and Indian Vulture (Gyps indicus) crashed with dramatic declines also observed in Nepal and Pakistan (BirdLife International 2008). Current evidences suggest that populations of these species are continuing to fall rapidly (Gilbert et al. 2006), to the extent that White-rumped Vulture has now declined in numbers by 99.9% since 1992 (Prakash et al. 2007). White-rumped Vulture has almost reached at the verge of extinction (Oaks et al., 2004). According to a recent survey (WWF-Pakistan, 2012), total populations of White-rumped Vulture, Indian Vulture and Egyptian vulture in Pakistan are 43, 55 and 457 respectively.

Diadema antillarum (Longspined Sea Urchin)

Anguilla anguilla (European Eel)

Whitethroat (Sylvia communis) in UK 90% in one year http://blx1.bto.org/birdtrends/species.jsp?year=2011&s=white

or skylark (Alauda arvensis) 50% decline in less than 10 years

http://blx1.bto.org/birdtrends/species.jsp?year=2011&s=skyla

and many other farmland birds in UK and Europe, see review by Ian Newton in 2004 in Ibis

In the Gulf of Bothnia, Baltic Sea, several sea spawning fish stocks have crashed. Among these are the sea spawning grayling (Thymallus thymallus) and the sea spawning whitefish (Coregonus lavaretus s. l.). Both species have been really abundant the grayling until 1970's and the whitefish until 1990's. One hypothesis to the causes of decline has been the enormous growth of filamentous algae caused by eutrophication and changes in ice cover duration. The larvae of these species dwell in the yuongest developmental stages in very shallow shore waters. The algae cause habitat loss and detrimental water quality.

The Humphead wrasse (Cheilinus undulatus) seems to have shown a severe decline in recent years, especially in the Red Sea around tourist areas. On endangered list ICUN since 2004 but anecdotally seems to have mostly disappeared from diver recordings around Sharm el Sheik.

coho salmon in northwestern US

Thunnus thynnus, Squalus acanthias, Gadus morhua, in the Northern Atlantic and Mediterranean. Passer domesticus in Western Europe.

although P. domesticus is still quite common, and not critically endangered. But Lepus europaeus has become quite rare in recent decades, at least in south-western Germany.

European eel is also an example. It has been very common since the Stone ages and was one of the three main fish eaten by people eversince until about 30 years ago when the eel stocks gradually decline and is only 1% of what it used to be. The same faith has hit Japanese eel and American eel.

Seahorses species are threatened throughout their range as a result of habitat loss and over-fishing. Are exploited for traditional Asian medicine markets, the pet trade, and for food.

Taxus baccata (Yew tree) is highly threatened in Himalayas due to removal of bark and leaves for anti cancer drug called Taxol. An article is attached showing its poor state of affairs.

Eider ducks (-50%) and Herring gulls (-30%) in the Baltic Sea. They are now red listed in Sweden (NT). Resons for the rapid decline is so far unknown. But a large scale ecosystem change influenced by increased eutrophication is a top suspect.

Acroporid corals (Acropora palmata and Acropora cervicornis) are down to 5% of their original abundance, in the best cases. This is througout its gegraphical range. And their cover and abundance is being actively diminished by white band disease and fireworm predation.

The passenger pigeon is a famous example of a common, abundant species that went extinct within decades of Europeans arriving in NA and hunting it.

Vulpes bengalensis is declining very rapidly from its distributional range

I can think of two instances of Arvicoline rodents, the souther water vole (Arvicola sapidus) and the Cabrera's vole in Spain, very common in the Quaternary and now very scarce

http://www.aragosaurus.com

Many Asian vulture species have sharply decreased in recent decades. Plenty of info at: http://www.vulturerescue.org/index_files/Page671.htm

The bluefin tuna population size has been reduced with 85% since 1973, and still it is heavily overfished.

http://www.iucnredlist.org/details/21858/0

@Zsolt Török

Eliomys quercinus

50% loss of range throughout Europe according to Temple & Terry 2009

Lot of common species of alkaline fens in Estonia have decreased in their distribution due to the end of traditional management (small fen meadows overgrown) or due to drainage for forestry (mainly about 50 years ago). Examples: Parnassia palustris, Primula farinosa, Pinguicula vulgaris, Carex davalliana, Dactylorhiza spp. etc.

Abies pinsapo for instance

Gnaphalium sylvaticum & Antennaria dioica are disappearing rapidly in the UK. I suspect as a consequence of atmospheric nitrogen deposition.

The paddy field fish species were very common even 15 - 20 years before in the Indian region but presently most of them are very rare. The reasons may be chemical fertilizer, high yeilding variety of paddy, global warming and so many. Proper research should be started immediately, otherwise we may lost so many of fish species in near future.

Dear Dr. John

Well, I can list out a number of common marine fish species (e.g. Atlantic bluefin tuna, Irish Sea cod, snowy grouper, red snapper, Atlantic cod....) that are exposed to over-exploitation (anthropogenic pressure) and facing rapid decline in population size. You may find these papers interesting:

1. http://baumlab.weebly.com/uploads/1/2/4/4/12445281/davies_2012_sci_rep.pdf

2. http://sci.odu.edu/gmsa/files/Sadovy_etal_2012.pdf

Best

Dola

Dear John,

In USA there are many Bumblebees that suffer of quick decline.

In West USA for example Bombus franklini and B. occidentalis

in google scolar you can find lots of new papers about it

cheers

Paolo

Pancratium maritimum

A beautiful Mediterranean coastal white Lilly with a lovely fragrance that attracts hundreds of different insect species from afar including an almost extinct large (obligate?) Sphinx moth. Up to about 20-30 years ago it would flower abundantly along the Israeli shores but it's now mainly restricted to protected zones. Similar decline is noted in Lebanon, Greece etc., and with it the whole insect community it supports. All because one species believes that hotels and tourism are what beaches are meant for... It's not only about the ecology and aesthetics, a variety of drugs (including Alzheimer's) are synthesized based on its bulb medicinal chemistry.

The Elephant Loxodonta africana, which once roamed across Nigeria, live only in a few protected areas today. Its documented as species currently vulnerable to extinction.

Vermivora chrysoptera, the population is rapidly decreasing because of habitat loss and hybridization with Vermivora cyanoptera.

http://www.abcbirds.org/abcprograms/science/watchlist/golden_winged_warbler.html

The European Hedgehog, Erinaceus europaeus, has shown dramatic population decrease in the the UK during the past 20 years. The reasons appear to include habitat loss and fragmentation; possible competition for food and nest resources with badgers in the countryside; ever diminishing suitable areas for foraging and nesting in suburban residential gardens; increased hazards posed by humans such as strimming, rat poison, slug pellets, trenches constructed during building work; reduced access to residential gardens. I am currently monitoring a hedgehog population in an area central to a small city but not accessible by the public. This will, hopefully, throw some light on year-on-year trends in small populations in a suburban area.

Toni Bunnell publications: http://www.tonibunnell.co.uk/hedgehog_menu.html

House Sparrow Passer domesticus has declined considerably in last 100 years. Once commonly seen in flocks of 20-30 individuals , this species has almost disappeared from the urban and suburban environments.

Another example is the Eurynorhynchus pygmeus, an Asiatic (and Euroasiatic) shorebird that is critically endangered because of habitat destruction. It is estimated that the population is around 600 wild birds, and it is decreasing faster with the passing of years. More info in http://www.birdlife.org/datazone/speciesfactsheet.php?id=3060

the facial tumour disease in Tazmanian devils, the hunting and habitat loss in Mesoamerican scarlet macaw (Ara macao cyanoptera) and Horned Guan (Oreophasis derbianus)

The European common toad, Bufo bufo is thought to suffer decline over some parts of its range. Fragmentation and road mortality plays quite a key role in this process.

I'm not sure if anyone has already mentioned this, but the house finch (Haemorhous mexicanus, formerly Carpodacus mexicanus) declined by roughly 60% within 1-2 years as the result of an epidemic. My colleagues and I documented this in a paper listed among my publications ("Sex, size, and plumage redness predict survival in an epidemic"). The population rebounded slightly but has never recovered to its formerly robust size.

The Western European population of Black-tailed godwits (Limosa limosa limosa) has declined dramatically since the mid 1900's. This is an (mostly) european population that has undergone a documented decline of ca.5% per annum since the 1980's. This has happened despite the inflow of funds for Agri-Environmental Schemes in its W European breeding range.

See details here:

Gill, J.A. et al 2007. Contrasting trends in two Black tailed Godwit populations: a review of causes and recommendations. Wader Study Group Bulletin 114: 43–50.

Dugongs were formerly common enough to be a food species for humans but are now rare or extinct in many parts of their former range (Indian Ocean~ Western Pacific), and endangered even in Australia.

Yep the house sparrow has been declining a lot.

@ Jose: Are you sure the black-tailed godwitt declined? Didn't it migrate. I'm not sure the European population has been declining, but I'm pretty sure that the migration pattern and occurrence of this species has been changing.

The European stag beetle Lucanus cervus has become extinct in part of its range and is declining elsewhere. Colin Hawes Royal Holloway University of London

Basically, two thirds of bird species associated to pre-1950ies farming practices have declined incredibly in NW-Europe, including a lot of waders like the black-tailed godwit. But I guess that's not fast enough for your question? Other species that have decreased >75% over the past 25 years in NW-Europe : corn bunting, yellowhammer, yellow wagtail, linnet, skylark, tree sparrow, house sparrow, turtle dove, ... As for butterflies, some declines are even stronger such as in the Wall brown (Lasiommata megera) which has changed in the course of 10 years from a fairly common species in Belgium to endangered. A similar story is happening to the Map butterfly (Araschnia levana), and some other species. In many species, this just seems to me like an extinction debt due to habitat loss and fragmentation ,culminating first in local extinction and as more and more patches are lost, regional extinction.

Without human intervention (forestry), dutch elm disease would also have wiped out most native populations of the Field elm and the Wych Elm.

The American elm (Ulmus americana), showed massive die-off across its eastern North America range through the mid-20th century due to Dutch elm disease (DED), an introduced fungal pathogen. While a very small percentage of U. americana seem to show natural immunity to DED, the overall effects of DED on U. americana are similar to the rapid functional extinction suffered by the American chestnut (Castanea dentata), also in the early to mid-20th century, in eastern N. America, and again due to an introduced fungal pathogen (which in the case of C. dentata produced chestnut blight). Both species continue to occur in small pockets of western N. America, where they were introduced in the latter part of the 19th century.

The house sparrow commonly encountered in the Indian sub-continent earlier, seems to vanished from the urban areas in India.

The passenger pigeon, which actually is extinct, having been shot out of the skies in the US.

rapid declines in birds of prey (raptors) associated with DDT/dieldrin/aldrin have been documented world wide with associated recoveries in some areas once the pesticides were banned .

Vultures have declined in many asiatic and other regions due to exposure to a veterinary product in carcasses of dead animals.

Turtle doves and house sparrows were once common and have declined in Europe due to a range of climatc and other factors.

Sand eels, the main food of many sea birds have declined in the North Atlantic. This is because their food source of micro-shrimps has declined due to sea temperature rises caused by climate change. .

John: How rapid is rapid? Can you define this in terms or say, species-specific generations, or at least years? From the examples you list I take it you're talking about an unreversed order(s)-of-magnitude decline in population size in something less than 5-10 generations?

In seaweeds there are some examples. For the Mediterranean I recomend you the paper http://dx.doi.org/10.1016/j.marpolbul.2005.06.014 about fucales in southern France. For the atlantic coast of northern Spain I recomend you the paper http://dx.doi.org/10.1080/09670262.2011.617840 about the retreat of laminariales between 1980 and 2000 (Figure 2 is very impressive).

The sparrow domestics is one of the species facing danger of extinction

Numbers of the common sparrow in the Uk have seen a dramatic decline in recent years to the extent that other species such as the Dunnock (Hedge Sparrow), previously seen in much smaller numbers than the common sparrow, has now superceded it.

See Redford et al 2013: Abundance as a conservation value (Oryx). Most interesting.

http://journals.cambridge.org/action//displayFulltext?fromPage=online&type=6&fid=S0030605312001615&aid=8807561&next=true&jid=ORX&volumeId=47&issueId=01&next=Y

Ricardo Bermejo - Within one or two generations - that pretty much excludes common species declining from habitat loss

Fiona Maisels - excellent paper - exactly what I've been dwelling on.

Actually, there are certain kinds of acute habitat loss that can affect shorter-generation species in a way that causes near-complete recruitment failure. For example, this can happen with sudden loss of a key habitat of migratory species, such as new dam closing off rearing and spawning migrations of anadromous fish in a large river basin, or the major alteration of a critical intermediate water body on the long-distance migratory path of shorebirds or waterfowl (multiple examples like these globally). Indeed I would argue these may be the most common types of one- or- two-generation-scale collapses at the species level.

Chytrid fungus, and whatever (poorly-understood) patholologies are associated with it, is indeed fast, and formerly widespread and abundant species have been decimated over large areas. But for the most part, at least in the temperate world where we have some higher-resolution time series of population data, I think the literature indicates this usually occurs progressively over time spans that subsume several generations. That is, local population groups may be seen to wink out within a single generation, but the collection of populations comprising a widespread species declines over a longer time frame. Hence, while rare endemic species may be wiped out quickly, widespread and abundant species tend to take a bit longer.

The take home message is that declines of widespread and abundant species, even from what we perceive to be a single acute cause, can be incremental and collective, not simultaneous, for reasons related to spatial complexity. This is a critical distinction from the standpoint of monitoring design and statistics, and for establishing restoration plans and recovery criteria for affected species and populations.

Fiona: Agreed a very interesting paper, and a long overdue line of inquiry- thank you. I've chewed on this a bit from the standpoint of spatial extent of species and their biological influence on other species and ecosystems. In fact it's interesting to ask whether for some species, spatial extent of range might be much more critical to their survival and evolutionary success than abundance itself. in other words, to me it seems to make a great deal of sense to consider abundance to be not the prime factor, but one of many biological expediencies for ensuring widespread distribution (which in turn provides for expanded intraspecific genetic, behavioral, and habitat diversity, higher likelihood of occupying refuge and subsequent recolonizing in the face of large-scale geologic or contagion catastrophe, etc.)

For North American fish species that I work on, we seem all too prone to consider a small handful of modestly abundant populations as sufficient to ensure the long-term persistence of species that were once superabundant and regionally widespread. In fact the fossil record and present-day patterns of diversity seem to suggest that few fish taxa survived that did not attain and maintain widespread distributions in the tectonically hyperactive western margin of North America survived Pieistocene and Holocene events. We should be worried.

The sparrow domesticus is commonly found in the vicinity of habitation, and build nests in the house, that's why it is named as domesticus. The main reason for its decline due to concrete structures and urbanisation. It is reported that the microwave towers are also one of the reason for its decline. The bird normally build nests in the thatched and tiled house roof, crevices, electric meter boxes, post boxes etc. But then the change in structure there is no space for nest building. keeping artificial nest boxes seems to be one alternative means to rebuild the population. Poaching is also contribute for its decline. creating awareness among the public on conservation measures, and methods of conservation will definitely yield fruitful results in building population of once superabundant species.

It depends on what you're classifying as 'rapid', but here are some potential examples I don't think have been mentioned yet are the crab-eating macaque (Macaca fascicularis) in tropical mainland and insular Southeast Asia (Eudey, 2008), and the bonnet macaque (Macaca radiata) and hanuman langur (Semnopithecus entellus) in India (Kumara et al., 2009).

For some general reading in abundant species and their conservation you should have a look at Gaston & Fuller (2007) and Gaston (2010, 2011).

Quick link to K. Gaston's pub list....

http://kevingaston.com/publications/

Starlings were not so long ago (about 10 years) very common birds and now are listed as endangered.

It's worth remembering that Anna's note about a decline in the occurrence of starlings (Sturnus vulgaris), and several earlier contributions about similar declines in the house sparrow (Passer domesticus), only apply to regions within the natural distributions of these species. But, both these bird species have also been introduced to many other regions of the world and have succeeded in the way invasive species typically do. Here in North America, both S. vulgaris and P. domesticus are year-round residents right across the continental United States and southern Canada. In my part of the world, starlings and house sparrows are both among the most ubiquitous bird species in the region. As well, the IUCN considers both species to be of "Least Concern".

Sparrows and starlings used to be extremely common in the uk, they were amongst the commonest of birds here too, but due to many factors, one of which being the increasing numbers of cats in the UK, they have declined to very low numbers. It appears to me that Starlings have fared even worse than the sparrow.

Common sparrows seem to be declining at a surprisingly fast rate in many parts of Europe. I suggest you check the progress reports of the European Common Bird Censuses, taking place in many Europen countries for other examples among birds. I suspect starlings and some larks could also be good examples, but don't have the data here.

A more dramatic example, already mentioned above is the catastrophic declines of Asian vultures, some of them declining by 95% in a few years following the generalized use of the veterinary drug diclofenc. See for instance Green et al. 2006 in Journal of Applied Ecology 43: 949-956.