Ημερολόγιο της/του thebeachcomber

Hedera is a relatively small genus (there is disagreement between sources as to how many species, with some taxa being relegated to subspecies in some sources, but for what it's worth POWO currently lists 19 species and a hybrid) of climbing plants native to northern Africa, Europe, and then stretching in a band across Asia as far east as Japan.

For those outside the native range of Hedera (but also for many within), the most well-known species is Hedera helix, the 'English ivy' or 'common ivy'. It is widely cultivated across the world, and is commonly planted to cover walls, fences, and other vertical surfaces. Unfortunately, it is now also widely naturalised as an invasive species around the world, readily escaping cultivation into nearby areas.

Like elsewhere, this situation seems to very much be the case in Australia. As I write this, there are ~900 iNat records of Hedera in Australia identified as H. helix (without having looked at them all yet, I strongly suspect a large % of these represent specimens that are planted rather than naturalised populations and need to be marked as cultivated, but let's assume for now they're all wild), and the AVH currently holds 157 collections identified as H. helix from Australia. In almost any suburb in Sydney, it is fairly easy to find at least a few properties or public spaces with H. helix planted over walls or fences, and indeed Hyde Park in the city has large sections where planted H. helix entirely blankets the ground. I am also increasingly seeing this species escaping cultivation in Sydney and invading nearby bushland.

However, all is not as it seems. Enter, Helix hibernica ('Atlantic ivy', 'Boston ivy').

There is a recent preprint, currently under review, entitled Extensive misidentification of European ivy species (Hedera L.): How taxonomically reliable are online biodiversity databases?, which can be read here: https://doi.org/10.21203/rs.3.rs-3693710/v1. It has a lot of useful information for us here. Here are the most important elements from that manuscript (with numbered references removed for readability):

"This is the case for ivies (Hedera L.), a small genus of recent diversification affected by extensive hybridization, where species delimitation has long been controversial. Besides, ivy species identification relies on inconspicuous microscopic characters (trichomes) of difficult interpretation while macroscopic characters (leaves, flowers or fruits) tend to have low taxonomic importance. In fact, the first feature in an ivy species diagnosis is the identification of the type of trichomes, while leaves are regarded as secondary diagnostic characters or even useless (Fig. 2). Even in cases where leaves are used for species diagnosis, it is the combination of leaf and trichome characteristics that allows species identification."

"The most important diagnostic character in Hedera is the type of trichomes (scale-like, stellate-rotate and stellate-multiangulate; Fig. 2A), whose assessment constitutes the first step on the species identification for the European ivy species...Indeed, the single area in the world where the three types of trichomes converge is the Iberian Peninsula in Europe, with H. helix as the representative of the multiangulate type, H. hibernica as the representative of the rotate type and H. iberica representing the scale-like type. Although the trichomes are quite distinct among the three species, towards the regions where they contact across their ranges it is frequent to observe individuals with intermediate features. Indeed, across H. hibernica distribution (from UK to Spain) whenever it contacts with H. helix, there are
populations whose individuals display intermediate forms of trichomes between the typical multiangulate of H. helix and the typical rotate of H. hibernica."

"In the case of the intermediate trichomes between H. helix and H. hibernica, leaves (or any other macromorphological trait so far analyzed) do not help species identification, as the two species show high variation and overlap (Fig. 2B)."

This third point is the crucial one here: you need to inspect the trichomes to reliably differentiate H. helix and H. hibernica. Why is this important? Because H. hibernica is also present in Australia. And indeed, it seems that a very large proportion of records, both photographic and vouchered, identified as H. helix are actually H. hibernica.

Let's skip across the Pacific to the US for a second, with a 2006 paper entitled Prevalence of different horticultural taxa of ivy (Hedera spp., Araliaceae) in invading populations (https://link.springer.com/article/10.1007/s10530-004-2424-6). They note that:

" Several similar forms are sold under the general common name of English ivy. They are groundcovers that have been used extensively in urban landscapes in the Pacific Northwest because of many desirable characteristics, including appearance, shade-tolerance, and easy propagation and growth. They have also been used for erosion control and slope stabilization, although their effectiveness in that role appears overrated (Parker 1996). As a result of their extensive use and biological characteristics, ‘English’ ivy has become one of the most ubiquitous invaders of urban and suburban forests in the Pacific Northwest (Reichard 2000)"

"As a result of both genetic analysis and morphological identification, 85% of the 119 samples were attributed to Hedera hibernica and 15% to H. helix. This indicates that H. hibernica is the taxon most responsible for the invasion by English ivy in the Pacific Northwest. Only 15% of the samples from the invading population were found to be Hedera helix"

Jumping back to Australia, it seems like we have a similar situation. VicFlora currently lists both H. helix and H. hibernica as naturalised in Victoria, and provides this explanation:

"Hedera hibernica is the more prevalent of the two species of Hedera naturalised in Victoria, but the name H. helix has been widely misapplied to this species."

"Hedera helix is the less common of the two species of Hedera naturalised in Victoria, known only from Ballarat, and Hallston Forest near Leongatha, but possibly more common that collections suggest. In South Australia H. helix is also rare, with H. hibernica being the prevalent species (Chris Brodie pers.comm. July 2020)."

Here is the VicFlora couplet for the two species:

Hairs on young leaves and stems in vegetative shoots stellate, usually stalked, hairs white or off-white, rays 4–8(–10), of different lengths and projecting at a range of angles from the leaf surface, giving an irregular appearance; leaves in vegetative shoots very rarely more than 8 cm wide, often lobed > 1/2 way to base with lobes usually longer than wide = H. helix

Hairs on young leaves and young stems in vegetative shoots stellate, generally sessile, the central part of the stellate hair occupying 1/6–1/3 of the diameter, hairs often pale yellowish brown, sometimes white or off-white, or orange or tan in the centre with rays mostly white or off-white, or indumentum a mixture of these colours, rays 4–12(–15) radiating in a plane parallel to the leaf blade, rays often of similar length; leaves in vegetative shoots occasionally > 8 cm wide, usually lobed < 1/2 way to base with lobes often as wide as long = H. hibernica

[reiterating per my comments above that the leaf characters noted at that couplet shouldn't be relied on, it's the hair characters that are diagnostic]

In addition to Victoria, the South Australia, Queensland and Western Australia herbaria also recognise that H. hibernica is naturalised in Australia in addition to H. helix. Indeed, NSW is the only one that still only recognises H. helix as being present.

What do the specimens in AVH say? As an aside, it's a bit annoying at the moment. Despite H. hibernica being unambiguously present in Australia, with four state herbaria recognising its presence as noted above, this species currently does not have the APC 'red tick' (I don't know if this is an oversight or a deliberate decision), so the AVH/ALA do not have a profile for the species. Because of this, all specimens IDed as H. hibernica in the AVH are being dumped into the genus. Anyway, there are currently 59 specimens with an ID of H. hibernica in the AVH. These are from:

Victoria (30 specimens)
South Australia (17)
NSW (3)
Queensland (4, including one that is not naturalised)
ACT (2)
WA (2)
Tasmania (1)

We have confirmed specimens from NSW, so why does NSW not recognise the species? Because the specimens are lodged at the Brisbane Herbarium, and a profile is only created for a species in PlantNET if the NSW Herbarium holds a specimen (I personally disagree with this policy, but that's an argument for another day).

So overall, it is clear that H. helix is not the only species present in Australia, with H. hibernica also present (there is actually a third species too, H. algeriensis. This one is a little bit confusing: APC lists it as naturalised in South Australia, and the South Australia eFlora agrees, yet the AVH has zero specimens from South Australia. Instead, it has 7 specimens from Victoria, yet VicFlora doesn't list it... So let's put this one aside for now). And at the very least in Victoria and South Australia, H. hibernica is the more commonly naturalised species. Yet on iNat, there are almost 900 Australian observations IDed as H. helix, and just 26 as H. hibernica!

This seems to me a very clear-cut case of a pervasive set of misidentifications driven by a combination of factors, including CV suggestions and the fact that a lot of people probably don't know H. hibernica even exists as a species, let alone knowledge of how similar it is to H. helix and the characters that are required to differentiate the two. From even just a brief skim of Australian observations, it is immediately clear that the vast majority, probably close to 100%, do not contain images that allow a legitimate ID to be made of either H. helix or H. hibernica, and that almost all of these records should be kept at genus. My plan is to therefore go through all Australian Hedera observations and, unless images of trichomes are present (eg this observation by @nomennudum: https://www.inaturalist.org/observations/141113195), I will be pushing them all back to genus, as I don't think it is useful to have so many observations IDed as H. helix when a) you cannot actually make that ID from the characters present, and b) a large proportion of these records are almost certainly actually H. hibernica. If noone has any objections to this, I'll do this in the next day or two.

As many of you would know, there are many Australian species on iNat that have their locations automatically obscured; at time of writing, the total number of species is ~2,800.

As a brief aside, the 'true' number is actually a bit lower than that, possibly several hundred lower. This seems oddly vague/inaccurate, but it's due to a mechanism on iNat to prevent bad actors unobscuring individual observations. Consider the following situation:
Someone uploads an observation of something with a sensitive location, it gets rightfully obscured. Three bad actors come along and each intentionally misidentify the observation as a common, unobscured species, eg a feral pigeon. The overall ID now shifts to said common species, and so the location gets unobscured, and they can access the sensitive location.
To combat this behaviour, iNat is setup so that if an ID of a sensitive species is added to an observation at any time, even if it is wrong + overruled or later withdrawn, the observation will remain obscured as a safeguard. So at least some of the species being included in that 2,800 is not because the actual species itself is obscured for Australia, but rather because there is at least one individual observation with at least one wrong ID (but now corrected) of an obscured species from somewhere else in the world. A classic example is the sulphur-crested cockatoo. Currently, 41 observations of this species are being automatically obscured in Australia. This is not because this species has any obscuration applied whatsoever, but because, on each of these observations, someone mistakenly added an ID of yellow-crested cockatoo (a threatened species from Southeast Asia obscured on iNat). All of these observations have since been correctly identified, but that initial wrong ID still applies obscuration.

But even accounting for that, take home message is that a lot of species are currently being obscured in iNat within Australia. Whilst many of these are being obscured based on state or federal sensitive species lists, there are also many that are being obscured only because of IUCN-based statuses. In many cases, these statuses do not correspond at all to Australian state or federal statuses as our conservation bodies/instruments and the IUCN apply different methodologies. On top of that, a lot of species being obscured due to IUCN statuses shouldn't actually have hidden locations, eg there are some Western Australian plant species that have an IUCN status of Near Threatened or Vulnerable despite being quite common and widespread, and having no federal or state status.

There has to be a reason for obscuring locations. If a species is threatened by collection, poaching, etc., then absolutely obscuration is a useful tool and will be implemented. But for other species, the threats are completely unrelated to these factors. For some species, the threats are clearing of habitat due to urban development, stochastic events such as fires due to small population size, increasing temperatures or sea levels due to climate change, etc. So obscuring the locations would not actually ameliorate any of these threats, as they are entirely unrelated to whether locations are public or not. Indeed in cases like these, it would almost certainly actually be detrimental to the species to obscure its locations on iNat. Consider a situation where eg a block of bush is being cleared for a housing development. Someone finds a species there and uploads an observation to iNat, but the location gets obscured, and by the time someone gets around to getting access to the true location, the vegetation has been cleared because no-one knew it was there due to the obscuration.

So obscuration should always be justified. As the main part of my job at the ALA, I'm working with iNat data on both the iNat and ALA ends. Under the National Framework for Restricted Access Species Data, we're trying to act consistently with the framework and make iNaturalist consistent with the state and territory sensitivity lists. So over the next few weeks, I will be opening the locations for all species on iNat where Australian observations are being automatically obscured due to an IUCN status only. Some of you may have noticed I have already done this for a small handful of species, mostly Tasmania stuff (see https://www.inaturalist.org/journal/thebeachcomber/86826-deobscuring-tasmanian-species).

As a few extra points of clarification:

1 . Perhaps the most important point here is to clarify how obscuration works on iNat just for the benefit of those who aren't completely familiar with the process.

a) When an observation is obscured on iNat, the true coordinates entered by the observer are randomly scrambled into a ~500 sq. km box around them. Any other user viewing that record will see the randomly generated coordinates with a box around them; they know the true coordinates are somewhere inside that box, but not the actual location. In addition to the coordinates, the date and time are also removed from the observation, so that only the month and year are displayed. Further, any identifications added to the record will have their timestamp altered to also only show the month and year.
b) When these records get exported to the ALA each week, the obscuration accompanies them, so the records are also obscured in the ALA, ie the coordinates shown in the ALA are the randomly generated ones, and the coordinate uncertainty is listed as somewhere around 29,000-30,000 m.
c) There are many different channels for getting access to the true coordinates if you're a researcher, land manager etc. I won't list them all here, but they include having users 'trust' you on iNat (can be turned on in profile settings) or directly requesting the data from the ALA (the true coordinates do go into the ALA, it's just that they are not made publicly available). So locations of obscured records are by no means lost, just more difficult to access. Also, when updates to coordinates/obscuration are made on iNat, these changes are automatically reflected in the ALA after a week or so.
d) There are two different types of obscuration on iNat.
i . Geoprivacy refers to users manually obscuring their own records. This is done at an individual observation level.
ii . Taxon geoprivacy refers to the automatic obscuration of records by the system. This is done at a taxon level.

2 . Crucial point: any records that you have manually obscured have not been deobscured. This only applies to species that were getting automatically obscured by the system, and only those being affected by an IUCN status.