NTS and taxonomy

General discussions of forests and trees that do not focus on a specific species or specific location.

Moderators: edfrank, dbhguru

Post Reply
User avatar
tsharp
Posts: 413
Joined: Mon Mar 15, 2010 12:04 pm

NTS and taxonomy

Post by tsharp » Tue May 14, 2013 11:33 am

NTS
We record most of our tree data at least to the genus and species level. Below this level are subspecies, varieties and forms. It seems to me we should be recording data at a lower taxonomic level when appropriate. I do not know how the difference between a subspecies and variety is defined or applied, but it appears to me that there is disagreement among taxonomists. It seems to me that NTS needs to pick an authority and go with it. I use USDA plants info, but they are not the controlling authority. This subject has implications for various databases kept by NTS (thinking of Matt M). Several years ago Jess Riddle wondered about this subject when White Basswood (Tillia heterophylla) was relegated from a species level to a variety level. I do not think anyone answered his question at the time.
TS

User avatar
edfrank
Posts: 4217
Joined: Sun Mar 07, 2010 5:46 pm

Re: NTS and taxonomy

Post by edfrank » Tue May 14, 2013 2:11 pm

Turner,

This is all part of the struggle in classification systems between Linnaean taxonomy http://rationalwiki.org/wiki/Linnaean_taxonomy and Cladistic taxonomy http://rationalwiki.org/wiki/Cladistics . The specific problem is that the amount of variation of one group of organism between different genus is not the same as those found in another group. The distinction between organisms do not end nice and neat at the species level as some species have more divisions below the species levels, hence the sub-species and variety. Cladistics has all but taken over in biology from Linnaean analysis, but cladistics does not have a useful ordering of species into family, genus, species, etc. that is as simple to use as the Linnaean system. To quote the article referenced above "some cladists argue that ranks for groups above species are too subjective to present any meaningful information, and so argue that they should be abandoned. Thus they have moved away from Linnaean taxonomy towards a simple hierarchy of clades." So we are stuck in trying to use a practical ordering system defined by Linnaeus, on a taxonomy system based upon a different organizational structure.

This is a round-about introduction, of which many of you are already familiar, upon which I am basing my opinion on the matter. I think we should be recording our tree data exactly as you suggest. We should be recording it to the species, subspecies, or variety at the lowest taxonomic level possible. White Basswood (var.) should be separated from Basswood. What drives this idea is that the variation between the two varieties might in another group be the difference between two species or even two genus, while here they are relegated to a difference in variety. Break things down as small as is practical. This may reignite the lumpers versus splitters arguments, but there is not really much gained by lumping, and overall over time the splitters tend to eventually win out anyway in most scientific classification systems.

I don't know what would be the best authority to use for the classifications. I would go with the USDA plants info because that is widely available and accessible to anyone on the internet. In some cases perhaps there will be a need to reconcile different authorities, but we can deal with those limited cases as they come up.

Edward Forrest Frank
"I love science and it pains me to think that so many are terrified of the subject or feel that choosing science means you cannot also choose compassion, or the arts, or be awe by nature. Science is not meant to cure us of mystery, but to reinvent and revigorate it." by Robert M. Sapolsky

User avatar
Don
Posts: 1560
Joined: Tue Mar 09, 2010 12:42 am

Re: NTS and taxonomy

Post by Don » Tue May 14, 2013 3:23 pm

Ed/Turner/Will-
As in many things, it's a question of balance. To take an extreme position, when I was overseeing the care of Grand Canyon's only T & E Species, the Sentry Milkvetch (Astragalus cremnophylax var. cremnophylax), the differences between this species varied little at the by-the-naked-eye level of analysis, and wasn't truly differentiated until inspected at the DNA analysis level. For my money, I'd have given them geographic variety label reflecting the discreet geographic location and been done with it...but on my Park Service salary, my money wouldn't have gone far...; > }

Grand Canyon National Park takes steps
to recover the endangered sentry milk-vetch
by Allyson Mathis

"Grand Canyon’s rarest plant, sentry milk-vetch (Astragalus cremnophylax var. cremnophylax), grows at only three locations on the South Rim.

This tiny member of the pea family with minute pale purple flowers favors very specific habitats at the canyon's edge. It grows in openings of the pinyon-juniper woodland, in shallow soil pockets atop the highly porous Kaibab Limestone. Listed as endangered in 1990, sentry milk-vetch is at risk of extinction because the plant exists in just three populations in very small numbers."
This was down-on-your-knees with a magnifying glass kind of scale...
Don
Don Bertolette - President/Moderator, WNTS BBS
Restoration Forester (Retired)
Science Center
Grand Canyon National Park

BJCP Apprentice Beer Judge

View my Alaska Big Tree List Webpage at:
http://www.akbigtreelist.org

User avatar
edfrank
Posts: 4217
Joined: Sun Mar 07, 2010 5:46 pm

Re: NTS and taxonomy

Post by edfrank » Tue May 14, 2013 3:38 pm

Don,

Your post actually strengthens my argument in many ways. If conservation managers and people in the horticultural world are worried about plant species to the variety level, should we not at least make the distinctions of species to the subspecies or variety level as well as we can to make our data com[atible?

Ed
"I love science and it pains me to think that so many are terrified of the subject or feel that choosing science means you cannot also choose compassion, or the arts, or be awe by nature. Science is not meant to cure us of mystery, but to reinvent and revigorate it." by Robert M. Sapolsky

User avatar
Steve Galehouse
Posts: 700
Joined: Mon Mar 08, 2010 11:50 pm

Re: NTS and taxonomy

Post by Steve Galehouse » Tue May 14, 2013 9:45 pm

Ed-

How does the cladistic approach deal with bi-generic crosses, such as Rhododendron x Kalmia, Cupressus x Chamaecyparis, or Heuchera x Tiarella? To me these implies a closer genetic association than a series or subgenera within an accepted genus that can't hybridise, such as Quercus(red can't cross with whites) and Pinus("soft" pines can't cross with "hard pines").

Steve
every plant is native somewhere

User avatar
edfrank
Posts: 4217
Joined: Sun Mar 07, 2010 5:46 pm

Re: NTS and taxonomy

Post by edfrank » Tue May 14, 2013 10:15 pm

Steve,

I am not an expert on this, so you would be better looking things up on the web yourself than me giving you the wrong answer. The process maps out where different DNA sequences (generally) diverged. I don't have any idea of the shape of the clad diagrams for oaks.

Ed
"I love science and it pains me to think that so many are terrified of the subject or feel that choosing science means you cannot also choose compassion, or the arts, or be awe by nature. Science is not meant to cure us of mystery, but to reinvent and revigorate it." by Robert M. Sapolsky

User avatar
KoutaR
Posts: 666
Joined: Tue Mar 16, 2010 3:41 am

Re: NTS and taxonomy

Post by KoutaR » Wed May 15, 2013 5:07 pm

Steve,

I cannot answer to your question (how does the cladistic approach deal with bi-generic crosses), but I have a few comments.

Taxa that cross are closer than taxa that don't cross by high probability, but this is not always the case. One example is the genus Picea, spruces. Sitka spruce (P. sitchensis), for example, hybridizes with white spruce (P. glauca) in the wild and at least with Yezo spruce (P. jezoensis), Serbian spruce (P. omorika) and Engelmann spruce (P. engelmannii) in plantations. However, according to the most complete molecular study so far, Sitka spruce is not closely related with any of these species. On the other hand, Norway spruce (P. abies), Siberian spruce (P. obovata) and Korean spruce (P. koraiensis) are very closely related and actually form broad zones of introgressive hybridization, Norway in the west, Korean in the east and Siberian in the middle. However, in the extensive crossing tests by Finnish Lauri Mikkola, Norway and Korean spruce were mostly incompatible. If I recall correctly, pollen tubes were unable to reach ovules. The evolution of such a mechanical obstacle doesn't obviously need large changes in the genome.

Another example are Eurasian Sorbus: whitebeams (subgenus Aria), wild service tree (Sorbus torminalis), true service tree (S. domestica) and dwarf whitebeam (S. chamaemespilus). Because they can hybridize with rowan (S. aucuparia) they have traditionally been placed to the same genus. However, molecular studies show that they are more closely related to genera like Malus, Pyrus, Amelanchier, Cotoneaster and Photinia than to Sorbus subgenus Sorbus. Therefore in some newer publications they have been moved to their own genera.

It has been known for a long time that Nootka cypress is not a Chamaecyparis. It has been moved to Xanthocyparis, then to Callitropsis and now it is included in Cupressus. Thus, there is not a cross Cupressus x Chamaecyparis to my knowledge.

About the original topic of this thread: NTS data should be recorded to the lowest (var.) level. E.g. Rocky Mountain Douglas-fir is separated from coastal Douglas-fir in the variety level according to the GRIN database (likely the best one) but their height potentials differ enormously.

Kouta

User avatar
Don
Posts: 1560
Joined: Tue Mar 09, 2010 12:42 am

Re: NTS and taxonomy

Post by Don » Wed May 15, 2013 6:13 pm

Ed-
Speaking as a lay person, the thrust of my post above was to suggest that at our level in NTS, if they can't be differentiated in the field, then we've gone far enough...IMHO, if it takes DNA analysis to take it to the next level, then we stick a fork in it, it's done.
Genetics is the preferred habitat of splitters...
-Don

edfrank wrote:Don,

Your post actually strengthens my argument in many ways. If conservation managers and people in the horticultural world are worried about plant species to the variety level, should we not at least make the distinctions of species to the subspecies or variety level as well as we can to make our data com[atible?

Ed
Don Bertolette - President/Moderator, WNTS BBS
Restoration Forester (Retired)
Science Center
Grand Canyon National Park

BJCP Apprentice Beer Judge

View my Alaska Big Tree List Webpage at:
http://www.akbigtreelist.org

Post Reply

Return to “General Discussions”