We receive many great photos from authors which, for one reason or another, are not selected for the journal cover (plus, we can only choose one photo for each issue!).  The blog gives us an opportunity to feature these author’s photos together with a lay summary. Here are a couple of images from papers recently published in the Centenary Special Issue (100:1).  The authors of the papers have written the indented, italic text below.

Demography of multi-stemmed trees

Andrew Tanentzap et al. recently published a paper in the Journal, and have sent in a beautiful picture of their study site.  The paper is in Volume 100 Issue 1, and can be read here.  Below are their pictures and discussion of them written by the authors.  Enjoy.

Understorey of Monks Wood National Nature Reserve (MWNNR), Cambridgeshire, England in May 2010.  The site is an ancient semi-natural mixed-ashwood where traditional coppicing has mostly been abandoned since the 1920s.  The ground is carpeted by common bluebells (Hyacinthoides non-scripta) and other early-spring flowers, such as dog’s mercury (Mercurialis perennis), where grazing pressures are low.  Multi-stemmed trees are also a common feature of the understorey, with a large hawthorn (Crataegus spp.) tree in the far-left foreground and many multi-stemmed hazel (Corylus avellana) trees scattered throughout the background.

Photo by Arnold Cooke

Tanentzap et al. model the growth, survival, and recruitment of hawthorn and hazel in MWNNR over 23 years to test whether being multi-stemmed improves tree growth and survival in relatively shaded forest understoreys and in the face of being eaten by muntjac deer (Muntiacus reevesi).  The growth and survival of whole trees increased with the number of stems they possessed.  However, the growth and recruitment of stems within these trees slowed as trees accumulated more stems because of competition for resources, though less-intensely when deer were abundant.  By producing multiple stems from their base, Tanentzap et al. suggest that trees can “persist” in one spot and thus maximize their long-term occupancy of forest understoreys.  This contrasts other life strategies that favour periodic “regeneration” by seed at different sites in the understorey, which may less effectively capture and retain space.  The position of plants along a continuum of “persistence” versus “regeneration” strategies will be influenced by factors such as their access to light, competition for resources amongst stems, and the extent of disturbances, such as browsing.  Understanding how plants shift between these strategies helps explain the remarkable structural and taxonomic diversity of temperate forests.

Non-vascular plants apply “adaptive management” to economize their water storage

Pascale Michel et al. recently published a paper in the Journal, and have sent in two beautiful pictures of their study organisms – bryophytes.  The paper is in Volume 100 Issue 1, and can be read here.  The authors have written the description below.

Bryophytes (mosses and liverworts) provide extensive ground cover in many habitats, contributing to numerous ecosystem functions and services. Many terrestrial bryophytes act like sponges, for example, absorbing and storing great amounts of water (ca. 400-1200% of their dry mass) to maintain high level of humidity in the environment. The physical structure of each individual bryophyte species determines their ability to retain water and reduce evaporation from wind flow and heat. Species that form small and dense cushions can maintain moisture the longest despite drying atmospheric conditions.

Photo by Pascale Michel

In the natural environment bryophytes frequently co-exist forming cushions comprising intimate mixtures of multiple species. The ability of these assemblages to retain water is greatly dependent on the individual species that constitute the community, and in particular is a function of individuals’ size and water holding capability. Furthermore, individual bryophytes often converge in size with their neighboring species to form smaller and denser cushions that are more efficient in retaining water. In contrast to vascular plants, bryophytes do not compete for water but share it and co-habit to economize their water storage. Thus, the contribution of multiple species cushions cannot be estimated by just adding up the contribution of each single species in this cushion, but interactions between species and physical plasticity of individuals need to be accounted for.

Photo by Pascale Michel