Research and Grants
Recent Publications
Stan, A.B., L.S. Rigg, and L.S. Jones, (2006) Dynamics of a managed oak woodland in northeastern Illinois , USA . Natural Areas Journal 26 : 187-197 Abstract
Goldblum, D. and L.S. Rigg, (2005) Dominant tree species growth responses to climate at the deciduous/boreal ecotone . Canadian Journal of Forest Research 35 : 2709-2718. Abstract
Rigg, L.S. (2005) Disturbance processes in maquis and forest, and the resulting spatial patterns of two emergent maquis conifers, New Caledonia . Austral Ecology . 30 :363-373. Abstract
Rigg, L.S. and S. W.
Beatty (2004) “The abundance and spatial distribution of herbaceous
and woody vegetation along old field margins in three upstate New York fields”
The Great Lakes Geographer.
11(1): 54-65. Abstract
Rigg, L.S. (2003) “Genetic Applications in Biogeography: An introduction.” Physical Geography, 24(5): 355-7. Refereed.
Diochon, A., L.S. Rigg, D. Goldblum, and N.O. Polans (2003) “The regeneration dynamics and genetic variability of sugar maple (Acer saccharum [Marsh.]) seedlings at the species’ northern growth limit, Lake Superior Provincial Park, Ontario, Canada.” Physical Geography, 24(5): 399-413. Abstract
Goldblum, D. and L.S. Rigg. (2002) Age structure and regeneration dynamics of sugar maple at the deciduous/boreal forest ecotone, Ontario, Canada. Physical Geography. In Press. Abstract
Rigg, L.S., N.J. Enright, G.L.W. Perry and B.P. Miller. (2002) The role of fog in the transition of woodland to rainforest. Biotropica, 34(2): 199-210 Abstract
Stojanovic, B., L.S. Rigg, and M.E. Konen. (2001) Stand structure of shagbark hickory (Carya ovata) and soil properties in an extremely fragmented woodlot in northeastern Illinois. Great Lakes Geographer. 8 (2);66-76. Abstract
Enright, N.J., L.S. Rigg, and T. Jaffré (2001) Environmental controls on species composition along a (maquis) shrubland to forest gradient on ultramafics at Mont Do, New Caledonia. South African Journal of Science 97:573-80. Abstract
Enright, N. J., J. Ogden, and L.S. Rigg (1999) Dynamics of forests with Araucariaceae in the western Pacific. Journal of Vegetation Science. 10(6): 793-804. Abstract
Rigg, L.S., N.J. Enright, and T. Jaffré (1998) Stand structure of emergent conifer Araucaria laubenfelsii, in maquis and rain forest, Mont Do, New Caledonia. Australian Journal of Ecology. 23:528-38
Kellman, M. C., R. Tackaberry, and L.S. Rigg (1998) Structure and function in two tropical gallery forest communities: Implications for forest conservation in fragmented systems. Journal of Applied Ecology. 35: 195-206. Abstract
Recent Research Grants
Argonne National Laboratory; Advanced Photon Source Beamtime (GSECARS Users).
(With Drs. M. Lenczewski and M. R. Frank, Geology, NIU), 36 hours on APS,
American Association of Geographers Research Grant, 2002-2003
American Association for the Advancement of Science and the National Science Foundation: Program for Women in International Scientific Collaboration (with Dr. M. Lenczewski, Geology, NIU), 2002
National Geographic Research and Exploration Grant, 2001-2002.
American Association of Geographers, Anne U. White Fund, 2001.
National Geographic Research
and Exploration Grant, 2000-2001
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Abstract: We examined the current composition and structure of a woodland in northeastern Illinois and evaluated the early effect of two prescribed burns. In an effort to increase white oak ( Quercus alba L.) regeneration, managers are reintroducing fire into the woodland understory. We assessed canopy species and compared understory vegetation and light, along with soil nutrient characteristics, between a burned and an unburned area. In addition, we monitored transplanted white oak seedlings to better understand their growth and survivorship in the woodland. The canopy was dominated by white oak, but non-oak species, particularly slippery elm ( Ulmus rubra Muhl.), ash (Fraxinus spp. L), and black cherry ( Prunus serotina Ehrh.), dominated the smaller size classes. There were no differences in woody and herbaceous vegetation, soil, and light characteristics between the burned and unburned area. White oak regeneration was poor which appeared to be due to low understory light levels associated with high density of the shrub prickly ash ( Zanthoxylum americanum Mill.) and high numbers of non-oak saplings. Transplanted seedlings also performed poorly, with low survival rates throughout the woodland as a whole. Mammalian herbivory is a likely cause of additional stress to white oak regeneration. Evidence of browsing of transplanted white oak seedlings was apparent throughout the study area. If white oak is to be a component of the future woodland, managers should consider: (1) implementing a more intensive management program aimed at reducing competition from non-oak species and (2) increasing light in the understory.
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Abstract: We consider the implications of climate change on the future of the three dominant forest species, sugar maple (Acer saccharum), white spruce (Picea glauca), and balsam fir (Abies balsamea) at the deciduous/boreal forest ecotone, Ontario, Canada. Our analysis is based upon individual species responses to past monthly temperature and precipitation conditions in light of GCM modeled monthly temperature and precipitation conditions in the study area for the 2080s. We then consider the tree species sensitivity to past climate with predicted conditions for the 2080 period. Sugar maple, located at its northern limit in the study area, shows the greatest potential for increased growth rates under the predicted warming and altered precipitation regime. White spruce is likely to benefit less, while the understory dominant, balsam fir, is likely to experience a decrease in growth potential. These projected changes would enhance the future status of sugar maple at its northern limit and facilitate range expansion northward in response to global warming.
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Recent Publications
Rigg, L.S. (2005) “Disturbance processes in maquis and forest, and the resulting spatial patterns of two emergent maquis conifers, New Caledonia” (Austral Ecology)..
Abstract:
Araucaria laubenfelsii and Araucaria montana are emergent conifers in maquis
and forest communities which are subjected to a combination of fire and cyclonic
disturbances. Both species are able to survive fire once stems reach a critical
size, but most seedlings and saplings are killed. Both species were found
to be clumped at most spatial scales for both saplings and trees in maquis,
resulting from a combination of patchy fire and a limited ability to disperse
seeds. The high degree of clumping indicated that fire disturbances may occur
relatively frequently in the field sites. Comparisons of burned and unburned
Araucaria montana sites suggest that clumping increases only slightly after
fire. Cyclonic disturbances are infrequent but may result in blow-down of
large individuals within both maquis and forest. All of the individuals blown-down
during the study had been previously fire scarred. Around tree blow-downs,
seedling and sapling densities can be high. This likely reflects both the
low dispersability of Araucaria seeds and enhanced moisture from the shading
of the adult, when it was alive. Disturbance by fire and wind play an important
role in the regeneration dynamics and spatial pattern of these species in
maquis in New Caledonia.
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Rigg, L.S. and S. W.
Beatty (2004) “The abundance and spatial distribution of herbaceous
and woody vegetation along old field margins in three upstate New York fields”
The Great Lakes Geographer.
11(1): 54-65.
Abstract:
Abandoned agricultural fields are a prominent landscape feature of the Great
Lakes region of North America. When fields are abandoned, species are influenced
by the nature of the surrounding landscape. This study examined the abundance
and spatial distribution of woody and herbaceous vegetation species along
old field margins (within 25 m of field edge or hedgerow) and the structure
and composition of adjacent hedgerows. Ordination and regression analysis
examined the preference of certain species, both herbaceous and woody, for
either edge or field interior environments. No herbaceous species were found
to decrease significantly with distance from the field edge, although many
species were found to occur with greater frequency in the "interior"
10 meters of the transects. A group of "edge" species was easily
identified with many occurring more in the first 10 meters of transects. In
general, total tree seedling densities significantly decreased with distance
from the edge, but this study found no correlation between woody species establishment
and species composition of hedgerows, except for sugar maple. Since this study
was able to quantify an edge community for both herbaceous and woody species,
given time, the edge communities may be used as a possible indicator of vegetation
change for the old field community.
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Diochon, A., L.S. Rigg, D. Goldblum, and N.O. Polans (2003) “The regeneration dynamics and genetic variability of sugar maple (Acer saccharum [Marsh.]) seedlings at the species’ northern growth limit, Lake Superior Provincial Park, Ontario, Canada.” Physical Geography, 24(5): 399-413.
Goldblum, D. and L.S. Rigg. (2002) Age structure and regeneration dynamics of sugar maple at the deciduous/boreal forest ecotone, Ontario, Canada. Physical Geography. In Press.
Abstract:
Sugar maple reaches its northern limit along the eastern shore of Lake Superior
marking the transition from the deciduous forest of eastern North America
to a predominantly boreal forest community. In light of regional warming trends
over the past 100 years and projections for even warmer conditions in the
future we sought to characterize the current age structure and regeneration
status of both sugar maple and boreal tree species within this ecotone zone.
Within Lake Superior Provincial Park (Ontario, Canada) a series of west-east
trending hills create numerous deciduous-boreal transition zones as sugar
maple occupy uplands and boreal species occupy valley bottoms, then once north
of the sugar maple limit, boreal species dominate all topographic positions.
Unlogged forest stands were sampled in the transition zone on ridges and slopes
both north and south of the sugar maple limit. Overall tree density and basal
area in sugar maple and boreal stands was similar across the ecotone, but
seedling density was significantly higher in plots dominated by sugar maple.
Moreover, sugar maple seedlings, but not saplings, were found slightly beyond
the adult sugar maple tree limit indicating the potential for range expansion
may be limited by microclimatic variables, namely cold air drainage.
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Rigg, L.S., N.J. Enright, G.L.W. Perry and B.P. Miller. (2002) The role of fog in the transition of woodland to rainforest. Biotropica, 34(2): 199-210
Abstract:
This study examined the role of shading and cloud-combing of moisture by scattered
trees of the emergent conifer, Araucaria laubenfelsii (Corbass.), in montane
shrubland-maquis at Mt Do, New Caledonia, in facilitating the succession from
shrubland to rainforest. Water collection experiments showed that these trees
combed significant amounts of water from low clouds on days when no rainfall
was recorded, and deposited this moisture on the ground beneath the tree canopy.
Analysis of photosystem II function in Araucaria laubenfelsii and five other
plant species using fluorometry revealed much lower photosystem stress in
plants beneath scattered Araucaria laubenfelsii than for individuals exposed
to full sunlight in the open maquis. Transition matrix analyses of vegetation
change based on 'the most likely recruit to succeed' indicated that the transition
from maquis to forest was markedly faster when emergent trees of Araucaria
laubenfelsii acted as nuclei for forest species invasion of the maquis. On
the basis of these lines of evidence it is argued that increased moisture
and shading supplied to the area directly below the crown of isolated trees
of Araucaria laubenfelsii in the maquis facilitates the establishment of both
conifer seedlings and other rainforest tree and shrub species. In the absence
of fire, rainforest can re-establish through spread in two ways; first, by
expansion from remnant patches, and second, from coalescence of small rainforest
patches formed around individual trees of Araucaria laubenfelsii.
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Stojanovic, B., L.S. Rigg, and M.E. Konen. (2001) Stand structure of shagbark hickory (Carya ovata) and soil properties in an extremely fragmented woodlot in northeastern Illinois. Great Lakes Geographer. 8 (2);66-76.
Abstract:
The stand structure of shagbark hickory (Carya ovata) and soil properties
in an extremely fragmented woodlot were examined in northeastern Illinois.
The goal of this preliminary study was to examine the effect of extreme forest
fragmentation (in a golf course environment) on the structure of oak-hickory
remnants and the impact of golf course management on soil properties associated
with the remnants. Seedling densities for shagbark hickory, density and basal
area for all trees present, and soil samples (pH, bulk density, organic matter,
and macronutrient concentrations) were obtained for each remnant and compared
to a larger forest plot (11 hectares). Shagbark hickory seeds collected from
the study site were germinated and grown under two different conditions: fertilized
and non-fertilized to assess the effect of nutrient amendments on seedling
growth and persistence. Seedling densities in woodlot remnants indicated shagbark
hickory is capable of establishing within a fragmented environment, however,
the stand structures indicated a lack of recent recruitment to the sub-canopy.
Soil nutrient concentrations were highly variable with no clear trends among
remnants. Fertilizer application to germinants indicated that shagbark hickory
seedlings have a negative sensitivity to golf course levels of nutrient application.
This research suggests that golf course management practices need to take
into consideration the persistence of long-lived tree species within fragments
to maintain a wooded course environment.
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Enright, N.J., L.S. Rigg, and T. Jaffré (2001) Environmental controls on species composition along a (maquis) shrubland to forest gradient on ultramafics at Mont Do, New Caledonia. South African Journal of Science 97:573-80.
Abstract:
The landscape scale pattern of distribution of maquis, maquis with emergent
conifers (Araucaria laubenfelsii), and rainforest, on ultramafic substrate
at Mt Do, New Caledonia is investigated in relation to soil and plant chemistry,
light and moisture. The structure and composition of these vegetation types
reflects the impacts of disturbance on the one hand, and of physiological
stresses on the other. Disturbance by fire is important in determining the
presence and abundance of maquis and rainforest at the landscape level and
is discussed in detail by Perry et al. elsewhere in this issue 1. The impacts
of light environments, water availability and soil chemistry on the succession
of vegetation from maquis to forest are also important. The chemistry of iron-crust
and eroded oxisol soils does not vary greatly between vegetation types, and
does not appear to define the distribution of species at the local scale.
Nevertheless, low concentrations of macronutrients (such as P) and slow rates
of biomass accumulation associated with this ultramafic landscape may be important
in slowing the rate of progression of the vegetation from maquis to forest.
Chlorophyll fluorescence studies of seedlings, saplings and trees in maquis
and forest provide strong evidence for severe reductions in photosynthetic
efficiency in photosystem II on clear days for seedlings growing in maquis.
The importance of increased water supply to plants establishing beneath emergent
araucarians in maquis through cloud-combing is also illustrated.
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Enright, N. J., J. Ogden, and L.S. Rigg (1999) Dynamics of forests with Araucariaceae in the western Pacific. Journal of Vegetation Science. 10(6): 793-804.
Abstract:
Several species of Araucaria and Agathis (Araucariaceae) occur as canopy emergents
in rain forests of the western pacific region, often representing major components
of total stand biomass. New data from permanent forest plots (and other published
work) for three species (Araucaria hunsteinii from New Guinea, A. laubenfelsii
from New Caledonia, and Agathis australis from New Zealand) are used to test
the validity of the temporal stand replacement model proposed by Ogden (1985)
and Ogden & Stewart (1995) to explain the structural and compositional
properties of New Zealand rain forests containing the conifer Agathis australis.
Here we propose the model as a general one which explains the stand dynamics
of rain forests with Araucariaceae across a range of sites and species in
the western Pacific. Forest stands representing putative stages in the model
were examined for changes through time in species recruitment, growth and
survivorship, and stand richness, density and basal area. Support for the
model was found on the basis of: 1. Evidence for a phase of massive conifer
recruitment following landscape-scale disturbances (e.g. by fire at the Huapai
site, New Zealand for Agathis australis); 2. Increasing species richness of
angiosperm trees in the pole stage of forest stand development (i.e. as the
initial cohort of conifers reach tree size; > 10 cm DBH); 3. A high turnover
rate for angiosperms (< 100 yr), and low turnover for conifers (>>
100 yr) in the pole stage, but similar turnover rates for both components
(50 - 100 yr) as forests enter the mature to senescent phase for the initial
conifer cohort; 4. Very low rates of recruitment for conifers within mature
stands, and projected forest compositions which show increasing dominance
by angiosperm tree species; 5. A low probability of conifer recruitment in
large canopy gaps created by conifer tree falls during the initial cohort
senescent phase, which could produce a second generation low density stand
in the absence of landscape scale disturbance; 6. Evidence that each of the
three species examined required open canopy conditions (canopy openness >
10 %) for successful recruitment. The evidence presented here supports the
temporal stand replacement model, but more long-term supporting data are needed,
especially for the phase immediately following landscape level disturbance
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Kellman, M. C., R. Tackaberry, and L.S. Rigg (1998) Structure and function in two tropical gallery forest communities: Implications for forest conservation in fragmented systems. Journal of Applied Ecology. 35: 195-206.
Abstract:
1. Composition, growth and turnover of trees in two species-rich tropical
gallery forests were examined to evaluate what community reorganization may
be needed to transform recently created tropical forest fragments into stable
refugia for regional forest biotas.
2. Rates of tree growth and turnover over a 5-year interval were comparable
to those recorded in continuous forests and in both communities there had
been some tree species turnover in the measured stem size classes during the
5-year interval.
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