DOI: 10.5061/dryad.tqjq2bw77
title: Fire promotes passive directed dispersal by birds

description: Recent work proposes that passive directed dispersal (PDD) occurs when
 tracking resources leads animal vectors to sites that favor plant
 establishment. For example, wildland fire can attract seed-dispersing
 animals via the magnet effect while generating the environmental
 conditions that benefit common animal-dispersed plants. To test the
 hypothesis that frequent fire results in PDD in pine savanna, we first
 documented the effect of frequent fire on common bird-dispersed plants by
 measuring relative plant abundance and per-individual fruit production in
 a long-term replicated fire experiment. Focal plants occurred more
 frequently and produced more fruit per plant in plots burned biennially
 compared to plots that had been unburned for six decades. We then used a
 crossover Before-After Control-Impact (BACI) experiment to measure the
 responses of birds and bird-dispersed seed rain after fire. Despite fire
 increasing seed dispersal distance, the magnet effect of fire resulted in
 more seeds of focal plant taxa arriving in recent burns than in areas
 burned 1-2 years prior. Collectively, these results suggest that wildland
 fire promotes PDD. Given that fire is a globally pervasive process in
 terrestrial ecosystems, PDD may be an important mechanism shaping plant
 communities.
description: # Fire enables passive directed dispersal by birds ## Investigators David
 S. Mason\ The Jones Center at Ichauway Kevin M. Robertson\ Tall Timbers
 Research Station Phillip G. Hahn\ Entomology and Nematology Department\
 University of Florida Emilio M. Bruna\ Wildlife Ecology and Conservation\
 University of Florida John L. Willis\ Southern Research Station\ USDA
 Forest Service Marcus A. Lashley\ Wildlife Ecology and Conservation\
 University of Florida ### Sampling information The experiments and
 sampling occurred between 2020–2022 at Tall Timbers Research Station in
 Tallahassee, Florida. USA. ## Sharing and Accessing Information Please
 contact the primary author
 ([david.mason@jonesctr.org](mailto:masond6@msu.edu)) for advice or further
 context. # Methodology # README: Data from: Fire enables passive directed
 dispersal by birds ## Description of data and file structure This data
 comprises ten spreadsheets related to passive directed dispersal by birds
 after fire across two distinct experimental frameworks. The first subset
 of data (1–3) characterizes vegetation and fruit production within a
 long-term fire-frequency experiment. The second subset (4–10) focuses on
 bird-mediated seed dispersal at artificial perches above seed traps in a
 second experiment embedded within a frequent-fire landscape. Some gaps
 exist due to environmental and technical constraints, including severe
 weather and intermittent game camera malfunctions. These brief periods of
 missing data are denoted as `NA` within the spreadsheets. ## Clean data
 files | File name | Description | | :------------------------------ |
 :------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Long-term-veg-focal-trials.csv | Presence/absence for focal taxa on vegetation transects experiment 1(long-term fire frequency / fire exclusion) | | Long-term-veg-focal-counts.csv | Counts for focal taxa on vegetation transectsexperiment 1(long-term fire frequency / fire exclusion) | | Fruit-availability-survey.csv | Fruit counts for focal taxa in experiment 1(long-term fire frequency / fire exclusion) | | 1\_Birds-annual.csv | Annual counts of seed-dispersing birds on artificial perches. Data from game cameras in experiment 2 (magnet effect) | | 3\_Birds-scat.csv | Binomial detection of defecation events on artificial perches for individual observations of seed-dispersing birds. Data from game cameras in experiment 2 (magnet effect) | | 4\_Perch-availability.csv | Distance, species, and foliage status of three nearest lower midstory perches | | 3\_TT-seed-removal.csv | Results of seed addition trials at seed traps | | 4\_TT-fruit-survey.csv | 1 m fruit transects for presence/absence of focal taxa at seed traps | | 10\_TT-seeds-species-annual.csv | Raw and adjusted annual seed totals for each species at each trap | #### Data specific information for: | Long-term-veg-focal-trials.csv | | :----------------------------- | | **Variable** | Values | Units | Explanation | | :----------- | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :---------- | :----------------------------------------------------------------------------------------------- | | PLOT | DRAINAGE, NB66, UNBURN, W2A, W2B, W2C, W75 | Categorical | Locations of plant surveys (n = 7) | | TREATMENT | CONTROL, FIRE | Categorical | Sites burned biennially or remain fire-excluded (\~60 years of no fire) | | TRANSECT | DRAINAGE.1, DRAINAGE.2, DRAINAGE.3, NB66.1, NB66.2, NB66.3, NB66.4, Unburned.1, Unburned.2, Unburned.3, Unburned.4, Unburned.5, Unburned.6, W2A.1, W2A.2, W2A.3, W2A.4, W2A.5, W2A.6, W2B.1, W2B.2, W2B.3, W2B.4, W2B.5, W2B.6, W2C.1, W2C.2, W2C.3, W2C.4, W2C.5, W2C.6, W75.1, W75.2, W75.3 | Categorical | Individual 30 m transects (1 m intercept) inside each location (n = 33) | | SPECIES | CAAM2, RHCO, RUBUS | Categorical | Focal species: CAAM2 = *Callicarpa americana*, RHCO = *Rhus copallinum*, and RUBUS = *Rubus* sp. | | SUCCESS | 0–8 | Integer | Number of plants that are focal taxa | | FAILURE | 0–57 | Integer | Number of plants that are not focal taxa | | TOTAL | 0–57 | Integer | Total number of plants in transect | #### Data specific information for: | Long-term-veg-focal-counts.csv | | :----------------------------- | | **Variable** | Values | Units | Explanation | | :----------- | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :---------- | :----------------------------------------------------------------------------------------------- | | PLOT | DRAINAGE, NB66, UNBURN, W2A, W2B, W2C, W75 | Categorical | Locations of plant surveys (n = 7) | | TREATMENT | CONTROL, FIRE | Categorical | Sites burned biennially or remain fire-excluded (\~60 years of no fire) | | TRANSECT | DRAINAGE.1, DRAINAGE.2, DRAINAGE.3, NB66.1, NB66.2, NB66.3, NB66.4, Unburned.1, Unburned.2, Unburned.3, Unburned.4, Unburned.5, Unburned.6, W2A.1, W2A.2, W2A.3, W2A.4, W2A.5, W2A.6, W2B.1, W2B.2, W2B.3, W2B.4, W2B.5, W2B.6, W2C.1, W2C.2, W2C.3, W2C.4, W2C.5, W2C.6, W75.1, W75.2, W75.3 | Categorical | Individual 30 m transects (1 m intercept) inside each location (n = 33) | | SPECIES | CAAM2, RHCO, RUBUS | Categorical | Focal species: CAAM2 = *Callicarpa americana*, RHCO = *Rhus copallinum*, and RUBUS = *Rubus* sp. | | DETECTIONS | 0–8 | Integer | Total number of focal taxa detections in transect | #### Data specific information for: | Fruit-availability-survey.csv | | :---------------------------- | | **Variable** | Values | Units | Explanation | | :----------- | :----------------------------------------- | :------------- | :----------------------------------------------------------------------------------------------- | | DATE | 10/4/2022–7/3/2024 | Month/Day/Year | 
 
 | | PLOT | DRAINAGE, NB66, UNBURN, W2A, W2B, W2C, W75 | 
 
 | Locations of fruit surveys (n = 7) | | TREATMENT | CONTROL, FIRE |
 Categorical | Sites burned biennially or remain fire-excluded (\~60 years
 of no fire) | | SPECIES | CAAM2, RHCO, RUBUS | Categorical | Focal
 species: CAAM2 = *Callicarpa americana*, RHCO = *Rhus copallinum*, and
 RUBUS = *Rubus* sp. | | FRUIT | 0–1,376 | Integer | # of fruit on
 individual plant | | NOTE | 
 
 | 
 
 | Used to cross-reference site names | #### Data specific information
 for: | 1\_Birds-annual.csv | | :------------------ | | **Variable** |
 Values | Units | Explanation | | :----------- | :---------------- |
 :---------- |
 :-------------------------------------------------------------------------------------------- | | SITE | 1, 4, 6, 7, 8, 17 | Categorical | Sites consisting of paired plots (n = 6) | | BURN.YR | B,C | Categorical | Identifies plots within sites by which year they were burned. B = first year, C = second year | | TRAP | A, B, C | Categorical | Identifier for traps within paired plots (n = 3 per plot, n = 6 per site) | | BURN | Y, N | Categorical | Y is &lt; 1 year since fire, N is 1-2 years since fire | | DETECTIONS | 4–495 | Integer | Number of annual bird observations at individual trap | #### Data specific information for: | 3\_Birds-scat.csv | | :---------------- | | **Variable** | Values | Units | Explanation | | :----------- | :--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :------------------- | :-------------------------------------------------------------------------------------------- | | SITE | 1, 4, 6, 7, 8, 17 | Categorical | Sites consisting of paired plots (n = 6) | | BURN.YR | B,C | Categorical | Identifies plots within sites by which year they were burned. B = first year, C = second year | | TRAP | A, B, C | Categorical | Identifier for traps within paired plots (n = 3 per plot, n = 6 per site) | | BURN | Y, N | Binary | Y is &lt; 1 year since fire, N is 1-2 years since fire | | DATE.TIME | 4/15/20 17:18– 3/24/22 11:20 | Month/Day/Year HH:MM | Date and time of bird observation | | DATE | 4/15/20–3/24/22 | Month/Day/Year | Date of bird observation | | SPECIES | American crow, American goldfinch, American robin, Bachman's sparrow, Blue jay, Blue-gray gnatcatcher, Brown thrasher, Brown-headed cowbird, Brown-headed nuthatch, Carolina chickadee, Carolina wren, Chipping sparrow, Common yellowthroat, Downy woodpecker, Eastern bluebird, Eastern kingbird, Eastern phoebe, Eastern towhee, Eastern wood-pewee, Grackle, Gray catbird, Great crested flycatcher, Hairy woodpecker, House finch, House wren, Indigo bunting, Mourning dove, Northern bobwhite, Northern cardinal, Northern flicker, Northern mockingbird, Orchard oriole, Passerellidae sparrow sp., Red-bellied woodpecker, Red-eyed vireo, Red-headed woodpecker, Red-winged blackbird, Rose-breasted grosbeak, Setophaga sp., Summer tanager, Tufted titmouse, Unknown finch, Unknown passerine, Unknown songbird, Unknown sparrow, Unknown thrush, Unknown woodpecker, Unknown wren, White-crowned sparrow, Yellow-billed cuckoo, Yellow-breasted chat, Yellow-throated vireo | Categorical | Taxon of bird observation | | SCAT | 0/1 | Binary | Indicates whether a defecation event is observed for the bird | #### Data specific information for: | 4\_Perch-availability.csv | | :------------------------ | | **Variable** | Values | Units | Explanation | | :----------- | :---------------------------------------------------------- | :------------- | :----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | DATE | 9/5/21–2/20/22 | Month/Day/Year | Date of sample | | SITE | 1, 4, 6, 7, 8, 17 | Categorical | Sites consisting of paired plots (n = 6) | | BURN.YEAR | B, C | Categorical | Identifies plots within sites by which year they were burned. B = first year, C = second year | | TRAP | A, B, C | Categorical | Identifier for traps within paired plots (n = 3 per plot, n = 6 per site) | | DISTANCE | 0.89–10.22 | Meters | Distance between seed trap and nearest artificial perch (n = 3 per trap) | | SPECIES | CAAM, CACO, LIST, MYCE, PINUS, PRSE, QUERCUS, RHUS, UNKNOWN | Categorical | Taxon of measured perch (CAAM = *Callicarpa americana*, CACO = *Carya cordiformis*, LIST = *Liquidambar styraciflua*, MYCE = *Myrica cerifera*, PINUS = *Pinus* spp., PRSE = *Prunus serotina*, QUERCUS = *Quercus* spp., RHUS, = *Rhus copallinum*, UNKNOWN = unidentified species) | | FOLIAGE | Y, N | Binary | Does the perch have foliage? | | NOTES | 
 
 | 
 
 | Includes additional details on foliage, taxon, and NA status | ####
 Data specific information for: | **3\_TT-seed-removal.csv** | |
 :------------------------- | | **Variable** | Values | Units | Explanation
 | | :------------ | :-------------------------------------------- |
 :------------- |
 :------------------------------------------------------------------------------------------------------- | | TRIAL | 1–6 | Categorical | Individual seed removal trials (sequential) | | START.DATE | 4/6/20–7/5/20 | Month/Day/Year | Trial start date | | END.DATE | 5/4/20–7/26/20 | Month/Day/Year | Trial end date | | SITE | 1, 4, 6, 7, 8, 17 | Categorical | Sites consisting of paired plots (n = 6) | | BURN.YR | B, C | Categorical | Identifies plots within sites by which year they were burned. B = first year, C = second year | | TRAP | A, B, C | Categorical | Identifier for traps within paired plots (n = 3 per plot, n = 6 per site) | | SPECIES | SIAL, HEAN, CAAN | Categorical | Species of seeds in trial (SIAL = *Sinapsis alba*, HEAN = *Helianthus annuus*, CAAN = *Capsicum annuum*) | | START.SEEDS | 10 | Integer | Number of seeds for each species at the start of the trial | | END.SEEDS | 0–10 | Integer | Number of seeds for each species at the end of the trial | | NOTES | 
 
 | 
 
 | Additional notes on individual trials | | SEEDS.RM | 0–10 | Integer |
 Number of seeds for each species lost during the trial | | INTERVAL |
 2020-04-06—2020-05-04 / 2020-07-05—2020-07-26 | Interval | Date range for
 each trial | | TRIAL.LENGTH | 6–28 | Integer | Duration of each trial
 (days) | | SEEDS.RM.RATE | 0–1.33 | Decimal | Seeds lost per day | |
 SEEDS.RM.PROP | 0.0–1.0 | Decimal | Proportion of seeds lost | #### Data
 specific information for: | **4\_TT-fruit-survey.csv** | |
 :------------------------- | | **Variable** | Values | Units | Explanation
 | | :----------- | :----------------- | :------------- |
 :----------------------------------------------------------------------------------------- | | DATE | 6/13/20–2/20/22 | Month/Day/Year | Date of sample | | SITE | 1, 4, 6, 7, 8, 17 | Categorical | Sites consisting of paired plots (n = 6) | | BURN.YR | B, C | Categorical | B is &lt; 1 year since fire, C is 1-2 years since fire | | TRAP | A, B, C | Categorical | Identifier for traps within paired plots (n = 3 per plot, n = 6 per site) | | DIRECTION | N, SE, SW | Categorical | Cardinal or subcardinal direction of fruit transect | | DISTANCE | 3–33 | Integer | Meters from trap along the transect (1 m point intercept) | | SPECIES | CAAM2, RHCO, RUBUS | Categorical | Focal taxa (CAAM2 = *Callicarpa americana*, RHUS = *Rhus copallinum*, RUBUS = *Rubus* sp.) | | PLANT | 0, 1 | Binary | Was focal plant present at transect point? | | FRUIT | 0, 1 | Binary | Was focal plant fruiting at transect point? | #### Data specific information for: | **10\_TT-seeds-species-annual.csv** | | :---------------------------------- | | **Variable** | Values | Units | Explanation | | :----------- | :--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :---------- | :------------------------------------------------------------------------------------------------- | | SITE | 1, 4, 6, 7, 8, 17 | Categorical | Sites consisting of paired plots (n = 6) | | BURN.YR | B, C | Categorical | B is &lt; 1 year since fire, C is 1-2 years since fire | | TRAP | A, B, C | Categorical | Identifier for traps within paired plots (n = 3 per plot, n = 6 per site) | | ID | 1BA, 1BB, 1BC, 1CA, 1CB, 1CC, 4BA, 4BB, 4BC, 4CA, 4CB, 4CC, 6BA, 6BB, 6BC, 6CA, 6CB, 6CC, 7BA, 7BB, 7BC, 7CA, 7CB, 7CC, 8BA, 8BB, 8BC, 8CA, 8CB, 8CC, 17BA, 17BB, 17BC, 17CA, 17CB, 17CC | Categorical | Unique identifier for individual traps (n = 36) | | UNIT | A, B, C, D, E, F, G, H, I, J, K, L | Categorical | Unique identifier for individual plots (n = 36) | | BURN | Y/N | Binary | Y is &lt; 1 year since fire, N is 1-2 years since fire | | SPECIES | CAAM2, RHUS, RUBUS | Integer | Focal taxa (CAAM2 = *Callicarpa americana*, RHUS = *Rhus copallinum*, RUBUS = *Rubus* sp.) | | RAW\.SEEDS | 0–1,090 | Integer | Annual seed rain in individual traps for taxa | | ADJ.RM | 0–4,165 | Integer | Annual seed rain in individual traps for taxa after adjusting for seed loss | | ADJ.FRUIT | 0–135,448 | Integer | Annual seed rain in individual traps for taxa after adjusting for fruit availability | | ADJ.SEEDS | 0–517,412 | Integer | Annual seed rain in individual traps for taxa after adjusting for seed loss and fruit availability |