PostPost----firefire response of bryophytes in association with understory vascular plants in the Lost Pines Ecosystem of Central Texas
Ingrid Karklins
Ingrid Karklins
An Undergraduate Research Scholars Thesis [email protected]
INTRODUCTION
Bryophytes (mosses, liverworts and hornworts) are early- responders to disturbances such as fire 1
Generally not included in post-fire vascular plant research 2
In 1954, Eula Whitehouse 3 noted the lack of research on Texas moss ecology
This is still true today
1Duncan and Dalton. 1982 2Ryoma, R. and S. Laaka-Undberg. 2005 3Whitehouse 1954 Ditrichum pallidum Bryophytes can grow on mineral soil Can reproduce as soon as moisture is available
May play an important role in the success of forest restoration
Particularly after fire 2,3,1.
1Kayes et al. 2010 2de las Heras-Ibáñez et al. 1991 3Ryoma and Laaka-Undberg. 2005
Funaria hygrometrica
OBJECTIVES OBJECTIVES
1. What are the site conditions that impact species presence and composition?
Hypotheses: a) Litter will limit plant cover
b) Canopy shade will limit plant cover
c) Soil moisture will limit plant cover OBJECTIVES
2. Will bryophyte and vascular plant dominance be different in burned and unburned areas?
Hypothesis Plant dominance will differ between burned and unburned areas OBJECTIVES
3. Are there associated groups of species found in burned versus unburned areas?
Hypothesis Burned and unburned areas will have distinctly different vascular plant and bryophyte communities and indicator species
METHODS STUDY AREA Two adjacent watersheds in the Bastrop Lost Pines Ecosystem The Price Creek watershed study area was heavily burned in the 2011 Bastrop County Complex Fire The Spicer Creek watershed was unburned, but displayed evidence of pine beetle damage in some areas TRANSECTS
Stratified random sampling method
5 transects in each of the two watersheds
5 quadrats per riparian and upland strata COVER ESTIMATES
Plant cover determined by percent cover estimates in three strata:
canopy – above 15 feet
understory -- 1.5 to 15 feet
groundcover – below 1.5 feet
RESULTS LITTER
Very poor soil conditions in burned areas Very thin litter Litter up to 6” thick in unburned areas
100 90 80 70 60 50 40 30 Litter % cover % Litter 20 10 0 Riparian Upland Riparian Upland Burned Burned Unburned Unburned
Litter percent cover in burned and unburned riparian and upland quadrats. Error bars are standard errors (n = 25 quadrats per category). LITTER HYPOTHESIS
Weak positive relationship between litter cover and plant cover in burned areas
100 90 80 70 60 50 40 30 20 10 R² = 0.1075
Groundcover plant % % cover plant Groundcover 0 0 20 40 60 80 100 Litter % cover Litter percent compared to groundcover plant percent cover in burned quadrats.
No evidence to support the hypothesis that litter limits plant cover at ground level SOIL MOISTURE
Differences in soil moisture Higher in burned areas than unburned areas Higher in riparian areas than in uplands Soil moisture levels were extremely low at the time of the study 14 12
10
8
6
Soil moisture Soil 4
2
0 Riparian Upland Riparian Upland Burned Burned Unburned Unburned Soil moisture in burned and unburned riparian and upland quadrats. Error bars are standard errors (n = 25 quadrats per category). SOIL MOISTURE HYPOTHESIS
Plant cover at ground level and soil moisture
Burned areas: Mixed trend among transects with no clear relationship (p > 0.05).
Unburned areas No relationship (p > 0.05).
NNNoNo evidence to support the hypothesis that soil moisture limited plant abundance at ground level CANOPY SHADE HYPOTHESIS
Canopy cover in unburned areas showed a weakly negative relationship to plant cover at ground level that was not significant
No evidence to support the hypothesis that increased canopy shade in unburned areas results in low plant cover at ground level
GROUNDCOVER
600
500
400
300
200 Burned Riparian Burned Upland 100 Unburned Riparian Groundcover species % cover % species Groundcover
0 Unburned Upland
Total percent groundcover of bryophytes and most abundant vascular plant species . BRYOPHYTES BURNED
Funaria hygrometrica and Ditrichum pallidum most abundant
Known disturbance species
Ditrichum pallidum Funaria hygrometrica BRYOPHYTES UNBURNED
Dominated by Leucodon julaceus and Weissia controversa
L. julaceus typically grows on bark substrate 1
1Reese 1984
Leucodon julaceus
PLANT SPECIES HYPOTHESIS
Species dominance in burned and unburned areas distinctly different
Supports the hypotheses that bryophyte and vascular plant dominance will be different INDICATOR SPECIES
PC-ORD analysis, based on MOSSES: frequency for all three Funaria hygrometrica* strata, identified 11 Ditrichum pallidum* indicator species Leucadon julaceus (Indicator value >30, p-value <0.05) Weissia controversa
GRASSES & FORBS Dichanthelium Polypremum procumbens
SHRUBS Baccharis Burned Ilex vomitoria Unburned Juniperus virginiana* Both Vaccinium arboreum
*Indicator value >50, p-value <0.05 Unburned Mostly unburned Mostly burned Burned PCPCPC- PC -ORD -- cluster -ORD analysis ORD ORD cluster ORD cluster analysisanalysis ORD ORD cluster analysis
DISCUSSION
Atrichum angustatum DISCUSSION SPECIES DIVERSITY
Groundcover in burned areas dominated by r-selected type species Aggressive colonizers High incidence of annual species 1
Vascular plant diversity higher in burned watershed Bryophyte diversity higher in unburned watershed
Overall trend: groundcover vegetation diversity increased after 2011 Bastrop fires
1During 1979 DISCUSSION BRYOPHYTES
Early responders to disturbance Clearly part of ecosystem recovery processes
Pioneer primary producers retain water cycle nutrients adapt to various habitats
Act as nurse plants Facilitate the reintroduction of vascular plants in disturbed ecosystems 1 F. hygrometrica & D. pallidum = early seral disturbance species pave the way for post-disturbance vascular succession
1Ren et al. 2010
Bryophyte and vascular plant interactions have an important role in the post-fire Bastrop Lost Pines Ecosystem recovery process
Bryophyte association patterns can be used to determine species that are appropriate for restoration of damaged or stressed environments. 1
Bryophytes can serve as a restoration tool Primary producers – set the stage for other species Particularly in riparian zones
1Fensham and Streimann 1997 REFERENCES
Brown, D. J., W. H. Nowlin, E. Ozel, I. Mali, D. Episcopo, M. C. Jones, and M. R. J. Forstner. 2014. Comparison of short term low, moderate, and high severity fire impacts to aquatic and terrestrial ecosystem components of a southern USA mixed pine/hardwood forest. Forest Ecology and Management 312312:179-192. de las Heras-Ibáñez, J., J. Guerra, and J. M. Herranz. 1991. Changes in floristic diversity and fugacity of bryophytes in burnt sites of SE Spain. Lindbergia 171717:11-17 16. Dietert, M. F. 1979. Studies on the gametophyte nutrition of the cosmopolitan species Funaria hygrometrica and Weissia controversa. The Bryologist 828282:417-431.82 Duncan, D. and P. L. Dalton. 1982. Recolonisation by bryophytes following fire. Journal of Bryology 112 2122:53-63. During, H. J. 1979. Life strategies of bryophytes: a preliminary review. Lindbergia 555:2-5 18. Fensham, R. J. and H. Streimann. 1997. Broad landscape relations of the moss flora from inland dry rainforest in north Queensland, Australia. Bryologist 100100:56-64. Hardman, A. and B. McCune. 2010. Bryoid layer response to soil disturbance by fuel reduction treatments in a dry conifer forest. Bryologist 113113:235-245. REFERENCES
Kayes, L. J., P. D. Anderson, and K. J. Puettmann. 2010. Vegetation succession among and within structural layers following wildfire in managed forests. Journal of Vegetation Science 212121:233-247.21 Reese, W. D. 1984. Mosses of the Gulf South: from the Rio Grande to the Apalachicola. Louisiana State University Press. Ren, H., G. Ma, Q. Zhang, Q. Guo, J. Wang, and Z. Wang. 2010. Moss is a key nurse plant for reintroduction of the endangered herb, Primulina tabacum Hance. Plant Ecology 209209:313-320. Ryoma, R. and S. Laaka-Undberg. 2005. Bryophyte recolonization on burnt soil and logs. Scandinavian Journal of Forest Research 202020:20 5-6. Shaw, A. J. and B. Goffinet. 2000. Bryophyte biology. Cambridge University Press. Whitehouse, E. 1954. The mosses of Texas : foreword. Bryologist 575757:53-63.57 GREAT THANKS TO
Dr. Georgianne W. Moore, Associate Professor, Department of Ecosystem Science and Management
Dale A. Kruse, Curator, S. M. Tracy Herbarium