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Monday 10 October 2016

Irrigation at work


As a change from more still photos, here's a (very) short video of the irrigation working during a site visit:



The sprinkler heads are set to have a 90 degree operational arc, so theoretically the water falls within the experimental plot.  The water for this comes from the storage butts that act as reservoirs for the intercepted 50% rainfall from the droughted plots.  I need to tweak the float switches still, to ensure they're all switching on and off at the same water depth, but otherwise, the system seems to be working so far.

This is something I'll be checking on regularly over the winter, as part of the ongoing monitoring of the site, the system, and the field generally.

Friday 9 September 2016

Buttercups and bedstraws, mouse-ears and geraniums


These four groups are abundantly scattered over Upper Seeds, and though it's fairly straightforward to recognise them quickly to genus, it can take time to become familiar with individual species, especially when many characteristics are similar.  This first survey season has also been a timely reminder not to assume I know what species I'm looking at, and to take a few minutes just checking some of the finer details to make sure. Time well spent with the small, shy species in grasslands like this!

Buttercups (Ranunculus species)

Always very familiar, with their shiny yellow flowers, and beloved of all pollinators and pollen eaters, these are not always so easy to tell apart without closer inspection.  I've so far identified three species of buttercup here - Small-Flowered, Creeping and Meadow.

Small-Flowerd Buttercup (R. parviflorus) (May 2016)
The small-flowered buttercup really stood out early in the season, as its pale yellowy-green leaves weren't familiar at all.  Mostly growing towards the western end of the field, at the top of the rise, a few localised patches showed up in late May as soft leafy mounds against the otherwise still-short cover before the growing season really got underway.

It's well-named, as the flowers are small and easily overlooked, lacking the shiny in-your-face nature of some of the other buttercups.

Groovy Creeping Buttercup stem

Creeping (R. repens) and Meadow (R. acris) buttercups are possibly the two species most often encountered, and easily mixed up, as they occur together in many meadows and other habitats (I know I have to get down and check these constantly!).

Once they're flowering, there's two main characteristics that tell them apart:  leaf shape, and whether the flower stem is grooved or not.

Both creeping and meadow buttercups have spreading sepals, but creeping buttercups also have a grooved flower stem (this isn't grooved on the meadow buttercup), and have three-lobed leaves where the terminal leaflet has its own short stem  (meadow buttercup leaves are more deeply cut).

One species I expected to find but haven't yet is the Bulbous Buttercup (R. bulbosus) - another shiny yellow-flowered species, but easily told from creeping and meadow by its reflexed (downturned) sepals.

Bedstraws (Galium species)

Another group where I have got three species on site; two familiar faces, and one that is another new one for my personal species list.  Hedge bedstraw (G. mollugo) and lady's bedstraw (G. verum) are quickly differentiated by the width of the leaf blades: hedge bedstraw has much broader leaves, with fewer leaves per whorl along the stem than lady's bedstraw.

Hedge bedstraw - wider leaves, white flowers


Lady's bedstraw - narrow leaf blades, yellow flowers



Slender bedstraw - widely spaced narrow leaves, white flowers
I was happy with these IDs - until the bedstraws started to flower, when I quickly realised I had white flowers on what I thought was lady's bedstraw (which has yellow flowers).  Whoops.  A salutory reminder not to get over-confident!

This surprise species I have now down as Slender Bedstraw (G. pumilum), and the process of looking closer at it has highlighted small but crucial differences from lady's bedstraw.  The flower colour is the really obvious characteristic; beyond that, the leaf whorls are much more widely spaced along the stem, giving slender bedstraw a less robust appearance.  Getting a hand lens out, will show you a few backward-pointing bristles along the edge of the leaves, as well as a lack of the distinctively rolled edges that characterise lady's bedstraw. 

Mouse-ears (Cerastium species)

Common Mouse-ear
Small, white-flowered plants that sparkle between the grass blades and round the side of other plant species; these are the little brothers of Stitchwort, and share the same starry flowers and simple paired leaf arrangements.

Two species on site: Common Mouse-ear (C. fontanum) - ubiquitous throughout the field, hairy but not sticky (see below!), with tiny white flowers and narrow pointed green leaves. 
Crowded terminal flowerhead of Sticky Mouse-ear









I've only seen Sticky Mouse-ear (C. glomeratum)  in one location so far.  It's stickily hairy, and has crowded terminal flower heads.  These, and the broader, more yellow leaves, make it stand out as something different from the common mouse-ear.  This is a plant I'll be keeping my eyes peeled for as time goes on and I get a closer look around my field.


Geraniums

One or other of two tiny pink-flowered species have been popping up in most places, like Little Jack Horner's plums - everywhere I stopped to do a survey, there was a small pink speck demanding I figure out which it is.  Like the buttercups, both these species were found growing closely together, making unravelling which was which tricky while there was still only foliage present.

Two tiny Geranium species (and other things!)
Both with similar, deeply cut foliage, and small pink flowers each with 5 petals - but if you look a bit closer.......

Cut-leaved Crane's-bill
Cut-leaved crane's-bill (G. dissectum) is a more sprawling, hairy plant, with flowers on short petioles close to the main stem, along with a number of leaves, giving an overall rather crowded impression of the flower position.

The petals are notched, and flowers appear to be a slightly deeper pink than the Long-Stalked Geranium (this is much more obvious when you can see them growing together).

Long-stalked Crane's-bill











Long-stalked Crane's-bill (G. columbinum) - is a gracile plant with larger, unnotched, paler pink petals forming individual flowers placed at the end of long delicate stems.  This is also less noticably hairy than the Cut-leaved crane's-bill. 



Just some of the small things that please me about working in grasslands like this.  There are many others, of course, and I hope to document some of those in later posts. 

Wednesday 17 August 2016

First cut, July 2016

Despite being delayed by sporadically heavy showers, we finally got Upper Seeds mown.  The guys at Wytham did a fantastic job, and left a very tidy field, complete with stripes.  The final stage - setting up the irrigation system and other field "furniture" - could now get going. 

After first cut, July 2016

We left butterfly strips around the field margins, well away from the experimental plots, to support the plant and invertebrate diversity so apparent in Upper Seeds during the Spring.

Butterfly strips were left around field margins

This approach means that early-Summer pupating butterflies and moths wouldn't be completely lost due to this first mowing - this freshly emerged Six-Spot Burnet (below) would have ended up in a silage heap, otherwise!

Six-spot Burnet moth (Zygaena filipendulae)  
The bullerfly strips  also mean that many plant species are allowed to flower, and later to set seed, providing valuable forage for insects and birds. 

Six-spot Burnet feeding on Field Scabious (Knautia arvensis)

Meadow Brown on Smooth Hawksbeard (Crepis capillaris)




















Monday 11 July 2016

Past land use at Upper Seeds - modern times

The management history of a parcel of land is often hard to establish; I'm lucky to be working on an estate that has an extensive archive, and which has been the focus of many different ecological surveys over the years.  Past land use has a bearing on current soil characteristics and ecology, and because of this, will influence future development and successional change.

This is particularly important when trying to restore or establish species-rich semi-natural calcareous grasslands, as these are considered to need several decades of appropriate management to begin to approach the diversity and complexity of historical grasslands.In common with many grassland areas across the country, Upper Seeds was ploughed during WW2, and put down to arable.  This may explain in part the apparent consistency of soil depth observed in the rainshelter post holes, as small-scale variation in underlying limestone bedrock topography would be erased through the erosive nature of ploughing. 

The Conservator at Wytham has kindly sent me some aerial photos of the area spanning 20 years from immediately post-war:

1.  Wartime ploughing of grasslands, followed by use as pasture

Upper Seeds, 1953
Upper Seeds, 1946


















2.  Under arable crops from 1960 to 1982:

Upper Seeds, 1960

Upper Seeds, 1968

The field wasn't managed between 1982 and 1984, from when it was deer-grazed only.  From November 2006, it has been sheep pasture, with Spring/Summer and Autumn grazing, with occasional use of a forage harvester to remove and prevent the encroachment of scrub, especially hawthorn, which is still present as small bushes and low-growing seedlings.  From now on, it will be mown as for hay, twice yearly.

Mowing as management for a UK calcareous grassland

Using mowing as a management strategy for Upper Seeds is a compromise driven primarily by issues around having grazing animals in fields with permanent structures and equipment (the rainshelters and irrigation systems).  Ideally, I'd have grazed it, as this is mostly how we manage calcareous grassland in the UK; in continental Europe, there is wider use of hay cropping, so there is justification for this as a management technique for this habitat.  The problems with having sheep on site include congregation around rainshelter legs, with nutrient addition and trampling in these locations; chewing, rubbing against and other damage of the pipes and upstanding elements of the irrigation.  The effect of mowing will be different to that of grazing, as grazing is continual low-level foraging, and selective, whereas mowing is indistriminate, biannual and less good for invertabrates.  Certainly in the 11 years that the sheep grazing and scrub removal has been carried out, Upper Seeds has moved on a long way from being a species-impoverished grassland, and I'm happy to receive comments and advice on how to better replicate grazing over Upper Seeds, as this is a more real-world scenario. 
 



Ready for first cut

It's been a very busy and full few weeks, during which I've had the chance to really get acquainted with the site in some depth.  On the hardware side, we've now got all ten rainshelters up, and just await the first cut before we can install the irrigation system that will carry the intercepted precipitation to the supplemented plots. 

Rainshelters in the sun
Before that can happen, baseline vegetation surveys had to be done - this comprised 100 metre-square quadrats, so I've been busy recording the species present, and their percentage cover, and taking a  biomass harvest from each quadrat location.  I've started sorting the biomass harvests into 6 categories: graminoids (grasses, sedges), legumes, non-leguminous forbs, woody species, bryophytes, and litter; once dried, this will give me an indication of productivity in each group.  This data will form the baseline reference against which all my subsequent surveys will be compared, so it's been important to get it right - grass ID continues to prove time-consuming, but I'd like to think I'm getting better, at least at some species; this is in no small part due to an excellent training day with Dominic Price of the Species Recovery Trust (http://www.speciesrecoverytrust.org.uk/), whose enthusiasm and knowledge kept us all going through a day of incessant rain - no mean feat!

I have grown to love the chalk grassland plant species over the last few years' surveying, and it's a pleasure to see some of them here on the limestone at Wytham, along with some familiar Lepidopteran faces in the guise of Marbled White and Common Blue butterflies.

Marbled Whites in the sun
This plant species assemblage makes for a very colourful sward, with pinks (Red Clover, Common Centaury, Pyramidal Orchids), purples (Self-heal, Field scabious, Common Vetch), whites (White Clover, Hedge Bedstraw, Common Mouse-ear, Fairy Flax) and yellows (Smooth Hawk's-beard, Perforate St. John's Wort, Bird's-foot Trefoil, Black Medick, Mouse-ear Hawkweed).  As the season has progressed, I've been interested to see more species coming into evidence and flowering, and by Friday last week, it looked very different to the low green grass-dominated sward it had been.

There's plenty of non-plant interest, too; the invertebrate community is rich and fascinating, and really warrants a page all of its own.  Similarly the bird life - there's long-tailed tits flitting about in the remaining scrub and woodland edge, a pair of kestrels regularly hunt over the hillside, and buzzards cruise by over the nearby woods.  In places, the flowering heads of grasses and Wild Parsnip is now shoulder-high to me, and providing shelter for a number of roe deer (including fawns) that up and run if I get too close.  The southern side of the field has been claimed by a male pheasant, who regularly makes me jump with his clattering call and accompanying rattle of feathers.  As I have just taken my final biomass harvest for this round, the field will now be mown, and will look very different next week to how it was when I left on Thursday:

Upper Seeds up to my knees (and beyond, in places!)




Monday 23 May 2016

Mine's a pint

Peter Horrocks, Vice Chancellor of the Open University, dropped by to investigate the irrigation verification I was running on campus:

Peter Horrocks, OU VC, exploring the test plot at Walton Hall
The combination of 81 pint pots, with sprinklers sending graceful arcs of water out to sparkle in the sunshine, drew a lot of attention.  So much of our research is done out of sight - behind closed doors, or out in the middle of nowhere - that it was a pleasure to share even a small aspect of what I'm doing with interested passers-by and colleagues.  I may install a deckchair so people can come and do science, while catching some rays!

Irrigation system - detail


Thursday 5 May 2016

Spring comes to Upper Seeds

It's been a long winter, much of which I've been in the office, so I've really enjoyed the monitoring visits down to Upper Seeds.  Getting out and about has always been a real cause for joy for me, and it's great to see Spring springing on site.  Not only rainshelters, but cowslips and bluebells are coming up at Upper Seeds!

Bluebells and cowslips at Upper Seeds

Being down on your hands and knees means you're much more likely to come face to face with our smaller fauna - my first furry ladybird, for one....

24-spot ladybird (Subcoccinella 24-punctata) - it really is covered in very fine down

... and a soltary bee checking out the footings, for another.


Solitary bee - one of the mining or mason bees?

Overhead, and over the nearby woodlands, buzzards have been cruising, adding their calls to the Spring soundtrack.  Fantastic. 

Wednesday 4 May 2016

Hello and welcome to my field!

What's in a name?

At the start of any project, arguably the most important thing is getting the name right.  Of course.  the simplest way would be to use the acronym - USCCE - but that's already in use.  I could have named it after someone - my supervisor, any of the other people involved in the initial conception or development or construction..... my dad..... Sir David Attenborough.... but that's a very boggy area to get into, egos being what they are (Dad would've been delighted) and would have been bound to miff someone.  After the main field?  Yes, possible, but Upper Seeds is the field and not the project; and Upper Seeds also has form in that it's the site of the TIGER and Gibson experiments, so there may be confusion over which project I'm referring to.  Rat Pen Field is the name my part of Upper Seeds is fondly known, but no-one else seems to like the name "Rat Pen Field Experimental Platform"......  So, I'm currently toying with Druscilla - Doctoral Research at Upper Seeds Climate Change Impacts Laboratory. Or maybe Muscari - Millenium Upper Seeds Climate change research installation.  All suggestions in a hat and the winning one gets to head up my blog :)

Let's do some introductions.....

I'm a research student with the Open University, looking into some of the impacts of changing climate patterns on plant communities.  Over the next three years, I'll be spending a lot of time out here, running the first field study on the Upper Seeds experimental platform, investigating changing rainfall regimes and developing the baseline data for everyone who comes along after me. I'll be talking more on my project in other posts, as things really get underway; for the time being, I'm busy project managing the on-site works involved in the setting out of the experimental blocks, and the construction of the rainshelters.

Upper Seeds - from quiet green field to experimental platform (in several moves)

The blank canvas that was Upper Seeds in February, before groundworks got underway

February 2016, prior to groundworks
 
The first thing to do was to survey in the location of all the experimental plots, using high-precision GPS technology, and marking them with canes and pegs so the contractors, Darran and Josh, would know where to excavate post holes for the rainshelter legs.

High tech and low tech kit - guess which I got to use....

Once the plots were all marked out, over to Darran and Josh to dig post holes and put together the rainshelters before erection.  The site slopes down towards the east, and has surface undulations, so it was important to ensure accurate profiles were in place for each plot. 
 
Profiles on marked plot
 Monitoring visits during the excavation of the post holes gave me the opportunity to have a good look at the soil profile and to take some undisturbed soil core samples from which I can gain some initial information about the soil structure and hydrology. 



Taking soil cores - I found the best way was to just hit it with a hammer!
 While I'm down on my hands and knees looking down holes, Darran and Josh were busy putting the rainshelters together and getting them fixed securely in the ground.  If Ikea did rainshelters, they'd probably come like this - flat-packed in kit form, and not as straightforward as perhaps you think they're going to be. 
  

Rainshelter goes up

The last parts to be added are the roof panels, and hey presto!  One complete rainshelter! 

Ta dah!

Now to get the other nine done......



Wednesday 27 April 2016

We are go!

We are excited to confirm that the first of many rainshelters for the RainDrop Experiment is in the ground.


After years of planning; from identifying a gap in the UK's long-term experiment (LTE) platform back in 2008, to a change in location from Parsonage Down to Wytham Woods, we are thrilled to see installation underway.

This is no mean feat and is only possible due to the fantastic partnerships that have been forged between the Ecological Continuity Trust, Oxford University, the Open University and the Patsy Wood Trust. Construction will require the assembly of in excess of 10,000 individual components, a process that is being overseen by PhD student Melanie Stone, Dr. Kadmiel Maseyk and Professor David Gowing (all from the Open University).

Construction underway on site


This is a really exciting project that will enable researchers to look at the effects of future climate change on semi-natural calcareous grassland.  By using a combination of rainshelters and solar-powered irrigation systems, the experiment will investigate how changes in the rainfall regime will affect the grassland community.



The two main treatments to be applied to plots are reduced rainfall (-50% on ambient levels) and increased rainfall (+50% on ambient levels). These will sit alongside control plots that receive ambient levels of rainfall and have no equipment installed, and procedural control plots which have rainshelters installed but which allow the rain to fall through to the ground beneath, and are designed to monitor any non-target environmental effects of the installed equipment.

RainDrop is intended as a new national research platform; within each experimental block there are currently four free plots to allow for further expansion of the experiment.