Effects of habitat modification on a tritrophic cascade in a lowland tropical rainforest

Description:
The impact of anthropogenic disturbance of tropical rainforests on ecosystem processes is poorly understood. In this study I investigate how habitat modification in tropical rainforests may mediate a tritrophic cascade with resultant effects on herbivory, a key ecosystem process. I adopt a stepwise approach through the trophic levels, assessing the relationships between forest quality and the bird community assemblage, and corresponding impacts on predation rates and herbivory. I measured the bird community across a forest quality gradient, surveying 24 sites within a modified lowland tropical rainforest in Borneo. At each sampling location I established two treatments, one using a large (2 x 2 x 1.5m) cage designed to exclude vertebrates, and the second a control where no vertebrate exclusion was in place. I measured predation rates using dummy caterpillars, and herbivory rates on selected leaves in each treatment at all sampling locations. I used piecewise structural equation modelling to develop a path model between predictor and response variables. I established a significant pathway between increasing forest quality, increased richness of the bird community and higher vertebrate predation rates. Conversely, invertebrate predation rates declined with increasing forest quality. The effect of increasing forest quality did not mediate a trophic cascade bringing about an increase in herbivory. However, the effect of vertebrate exclusion mediated a trophic cascade and an increase in herbivory in higher forest quality, where invertebrate predation levels are lower. The results of the study therefore reflect the dampening of the tritrophic cascade across a forest quality gradient, and high functional redundancy in predatory function in forests of low quality. The study also highlights the importance of avian predatory function in forests of higher quality. A reduction in large vertebrate predators in undisturbed tropical rainforests may therefore result in cascading effects on herbivory, which may in turn have implications for primary productivity and nutrient cycling. These findings have significant implications for tropical forest conservation and management. Further research should place emphasis on addressing the effects of the loss of apex predators on key ecosystem processes.
Project: This dataset was collected as part of the following SAFE research project: The effects of habitat modification on a tritrophic cascade in a lowland tropical rainforest
Permits: These data were collected under permit from the following authorities:

Sabah Biodiversity Centre (SABC) (Research licence JKN/MBS.1000-2/2 JLD.8 (66))
Sabah Biodiversity Centre (SABC) (Research licence JKM/MBS.1000-2/2 JLD.8 (61) )

XML metadata: GEMINI compliant metadata for this dataset is available here
Files: This dataset consists of 2 files: FraserExclusionPlots_AFedit_150820.xlsx, FraserAdam_TFE_2019_SAFE_AudioFiles.zip
FraserExclusionPlots_AFedit_150820.xlsx
This file contains dataset metadata and 3 data tables:

Bird point counts (described in worksheet PointCounts)
Description: Repeated bird point counts at all sites
Number of fields: 89
Number of data rows: 72
Fields:

Visit_Code: Unique site x replicate code (Field type: id)
Plot: SAFE Project plot ID (Field type: location)
Visit: Visit number (Field type: replicate)
Date: Date of point count (Field type: date)
Time_Start: Time at start of point count (Field type: time)
Time_Finish: Time at end of point count (Field type: time)
Weather: Observations on weather conditions (Field type: comments)
Ashy.tailorbird: Count of individuals (Field type: abundance)
Asian.fairy.bluebird: Count of individuals (Field type: abundance)
Asian.paradise.flycatcher: Count of individuals (Field type: abundance)
Asian.red.eyed.bulbul: Count of individuals (Field type: abundance)
Banded.broadbill: Count of individuals (Field type: abundance)
Banded.bay.cuckoo: Count of individuals (Field type: abundance)
Black.and.red.broadbill: Count of individuals (Field type: abundance)
Black.and.yellow.broadbill: Count of individuals (Field type: abundance)
Black.capped.babbler: Count of individuals (Field type: abundance)
Black.headed.bulbul: Count of individuals (Field type: abundance)
Black.headed.pitta: Count of individuals (Field type: abundance)
Black.naped.monarch: Count of individuals (Field type: abundance)
Blue.eared.barbet: Count of individuals (Field type: abundance)
Blue.headed.pitta: Count of individuals (Field type: abundance)
Bold.striped.tit.babbler: Count of individuals (Field type: abundance)
Bornean.banded.pitta: Count of individuals (Field type: abundance)
Bornean.spiderhunter: Count of individuals (Field type: abundance)
Bronzed.drongo: Count of individuals (Field type: abundance)
Brown.barbet: Count of individuals (Field type: abundance)
Brown.fulvetta: Count of individuals (Field type: abundance)
Brown.backed.sunbird: Count of individuals (Field type: abundance)
Brown.throated.sunbird: Count of individuals (Field type: abundance)
Bushy.crested.hornbill: Count of individuals (Field type: abundance)
Chestnut.backed.scimitar.babbler: Count of individuals (Field type: abundance)
Chestnut.munia: Count of individuals (Field type: abundance)
Chestnut.rumped.babbler: Count of individuals (Field type: abundance)
Chestnut.winged.babbler: Count of individuals (Field type: abundance)
Collared.kingfisher: Count of individuals (Field type: abundance)
Common.emerald.dove: Count of individuals (Field type: abundance)
Cream.vented.bulbul: Count of individuals (Field type: abundance)
Crested.fireback: Count of individuals (Field type: abundance)
Crimson.sunbird: Count of individuals (Field type: abundance)
Dark.necked.tailorbird: Count of individuals (Field type: abundance)
Diards.trogon: Count of individuals (Field type: abundance)
Dusky.broadbill: Count of individuals (Field type: abundance)
Fiery.minivet: Count of individuals (Field type: abundance)
Fluffy.backed.tit.babbler: Count of individuals (Field type: abundance)
Gold.whiskered.barbet: Count of individuals (Field type: abundance)
Great.argus: Count of individuals (Field type: abundance)
Greater.green.leafbird: Count of individuals (Field type: abundance)
Greater.racket.tailed.drongo: Count of individuals (Field type: abundance)
Green.broadbill: Count of individuals (Field type: abundance)
Grey.headed.babbler: Count of individuals (Field type: abundance)
Helmeted.hornbill: Count of individuals (Field type: abundance)
Hooded.pitta: Count of individuals (Field type: abundance)
Lesser.green.leafbird: Count of individuals (Field type: abundance)
Little.spiderhunter: Count of individuals (Field type: abundance)
Long.billed.spiderhunter: Count of individuals (Field type: abundance)
Malaysian.blue.flycatcher: Count of individuals (Field type: abundance)
Moustached.babbler: Count of individuals (Field type: abundance)
Orange.bellied.flowerpecker: Count of individuals (Field type: abundance)
Pied.fantail: Count of individuals (Field type: abundance)
Plain.sunbird: Count of individuals (Field type: abundance)
Plaintive.cuckoo: Count of individuals (Field type: abundance)
Puff.backed.bulbul: Count of individuals (Field type: abundance)
Purple.naped.sunbird: Count of individuals (Field type: abundance)
Raffless.malkoha: Count of individuals (Field type: abundance)
Red.bearded.bee.eater: Count of individuals (Field type: abundance)
Red.naped.trogon: Count of individuals (Field type: abundance)
Red.throated.barbet: Count of individuals (Field type: abundance)
Rhinoceros.hornbill: Count of individuals (Field type: abundance)
Rufous.collared.kingfisher: Count of individuals (Field type: abundance)
Rufous.crowned.babbler: Count of individuals (Field type: abundance)
Rufous.fronted.babbler: Count of individuals (Field type: abundance)
Rufous.tailed.tailorbird: Count of individuals (Field type: abundance)
Rufous.tailed.shama: Count of individuals (Field type: abundance)
Scarlet.rumped.trogon: Count of individuals (Field type: abundance)
Short.tailed.babbler: Count of individuals (Field type: abundance)
Short.toed.coucal: Count of individuals (Field type: abundance)
Slender.billed.crow: Count of individuals (Field type: abundance)
Sooty.capped.babbler: Count of individuals (Field type: abundance)
Spectacled.bulbul: Count of individuals (Field type: abundance)
Spectacled.spiderhunter: Count of individuals (Field type: abundance)
Violet.cuckoo: Count of individuals (Field type: abundance)
White.crowned.hornbill: Count of individuals (Field type: abundance)
White.crowned.shama: Count of individuals (Field type: abundance)
Woodpecker.sp.: Count of individuals (Field type: abundance)
Wreathed.hornbill: Count of individuals (Field type: abundance)
Yellow.breasted.flowerpecker: Count of individuals (Field type: abundance)
Yellow.crowned.barbet: Count of individuals (Field type: abundance)
Yellow.rumped.flowerpecker: Count of individuals (Field type: abundance)
Yellow.vented.bulbul: Count of individuals (Field type: abundance)

Leaf herbivory (described in worksheet LeafHerbivory)
Description: Within each treatment, I tagged and numbered seven leaves. I chose a variation of leaf ages within each treatment, as recommended by Coley and Barone (1996). I measured leaf area on all tagged leaves at monthly intervals, as recommended by Coley and Barone (1996) and detailed in Harrison and Banks-Leite (2019), between March and May 2019. I calculated arthropod herbivory rate using ImageJ software (Schindelin et al. 2012) to determine the percentage leaf area lost (LAL) over time.
Number of fields: 9
Number of data rows: 336
Fields:

Site: SAFE Project plot ID (Field type: location)
Treatment: Experimental treatment: inside or outside exclusion cage? (Field type: categorical)
Leaf: ID number for each leaf (Field type: replicate)
DateFirstObs: Date of first leaf observation (Field type: date)
LeafArea: Leaf area at first observation (Field type: numeric)
DateFinalObs: Date of final leaf observation (Field type: date)
FinalLeafArea: Leaf area at last observation (Field type: numeric)
LostArea: Area of leaf lost to herbivory (Field type: numeric)
PercentLostArea: Percent of leaf area lost to herbivory (Field type: numeric)

Insect predation data (described in worksheet PredationData)
Description: I assessed predation rates on invertebrates by placing five plasticine dummy caterpillars within each treatment, at each sampling location. The methods were based on those described in Howe, Lövei and Nachman (2009) Roslin et al. (2017) and Roels, Porter and Lindell (2018). I placed five fresh plasticine caterpillars at least one metre apart from each other within the treatment and recovered the caterpillars after 14 days. I quantified predation attempts on each set of caterpillars within each treatment, following guidance on visual predator identification as per Low et al. (2014).
Number of fields: 9
Number of data rows: 144
Fields:

Visit_Code: Unique site x replicate code (Field type: id)
Plot: SAFE Project plot ID (Field type: location)
Visit: Visit number (Field type: replicate)
Date: Date of point count (Field type: date)
Treatment: Experimental treatment: inside or outside exclusion cage? (Field type: categorical)
Invertebrate: Number of plasticine invertebrate mimics attacked by invertebrate predator (Field type: numeric)
Mammal: Number of plasticine invertebrate mimics attacked by mammalian predator (Field type: numeric)
Bird: Number of plasticine invertebrate mimics attacked by avian predator (Field type: numeric)
Other: Number of plasticine invertebrate mimics attacked by predator that couldn't be identified (Field type: numeric)
FraserAdam_TFE_2019_SAFE_AudioFiles.zip
Description: Audio files recorded during points counts
Date range: 2019-03-04 to 2019-05-10
Latitudinal extent: 4.6815 to 4.7435
Longitudinal extent: 117.5396 to 117.5971
Taxonomic coverage: All taxon names are validated against the GBIF backbone taxonomy. If a dataset uses a synonym, the accepted usage is shown followed by the dataset usage in brackets. Taxa that cannot be validated, including new species and other unknown taxa, morphospecies, functional groups and taxonomic levels not used in the GBIF backbone are shown in square brackets.
 -  Animalia  -  -  Chordata  -  -  -  Aves  -  -  -  -  Piciformes  -  -  -  -  -  Picidae  -  -  -  -  -  Ramphastidae  -  -  -  -  -  -  Psilopogon  -  -  -  -  -  -  -  Psilopogon duvaucelii  -  -  -  -  -  -  -  Psilopogon chrysopogon  -  -  -  -  -  -  -  Psilopogon mystacophanos  -  -  -  -  -  -  -  Psilopogon henricii  -  -  -  -  -  -  Caloramphus  -  -  -  -  -  -  -  Caloramphus fuliginosus  -  -  -  -  Coraciiformes  -  -  -  -  -  Alcedinidae  -  -  -  -  -  -  Todiramphus  -  -  -  -  -  -  -  Todiramphus chloris  -  -  -  -  -  -  Actenoides  -  -  -  -  -  -  -  Actenoides concretus  -  -  -  -  -  Meropidae  -  -  -  -  -  -  Nyctyornis  -  -  -  -  -  -  -  Nyctyornis amictus  -  -  -  -  Galliformes  -  -  -  -  -  Phasianidae  -  -  -  -  -  -  Argusianus  -  -  -  -  -  -  -  Argusianus argus  -  -  -  -  -  -  Lophura  -  -  -  -  -  -  -  Lophura ignita  -  -  -  -  Columbiformes  -  -  -  -  -  Columbidae  -  -  -  -  -  -  Chalcophaps  -  -  -  -  -  -  -  Chalcophaps indica  -  -  -  -  Passeriformes  -  -  -  -  -  Corvidae  -  -  -  -  -  -  Corvus  -  -  -  -  -  -  -  Corvus enca  -  -  -  -  -  Pellorneidae  -  -  -  -  -  -  Pellorneum  -  -  -  -  -  -  -  Pellorneum capistratum  -  -  -  -  -  -  Alcippe  -  -  -  -  -  -  -  Alcippe brunneicauda  -  -  -  -  -  -  Trichastoma  -  -  -  -  -  -  -  Trichastoma malaccense  -  -  -  -  -  -  Malacopteron  -  -  -  -  -  -  -  Malacopteron magnirostre  -  -  -  -  -  -  -  Malacopteron magnum  -  -  -  -  -  -  -  Malacopteron affine  -  -  -  -  -  Cisticolidae  -  -  -  -  -  -  Orthotomus  -  -  -  -  -  -  -  Orthotomus ruficeps  -  -  -  -  -  -  -  Orthotomus atrogularis  -  -  -  -  -  -  -  Orthotomus sericeus  -  -  -  -  -  Rhipiduridae  -  -  -  -  -  -  Rhipidura  -  -  -  -  -  -  -  Rhipidura javanica  -  -  -  -  -  Muscicapidae  -  -  -  -  -  -  Trichixos  -  -  -  -  -  -  -  Trichixos pyrropygus  -  -  -  -  -  -  Cyornis  -  -  -  -  -  -  -  Cyornis turcosus  -  -  -  -  -  -  Copsychus  -  -  -  -  -  -  -  Copsychus stricklandii  -  -  -  -  -  Dicaeidae  -  -  -  -  -  -  Dicaeum  -  -  -  -  -  -  -  Dicaeum everetti  -  -  -  -  -  -  -  Dicaeum trigonostigma  -  -  -  -  -  -  Prionochilus  -  -  -  -  -  -  -  Prionochilus maculatus  -  -  -  -  -  -  -  Prionochilus xanthopygius  -  -  -  -  -  Campephagidae  -  -  -  -  -  -  Pericrocotus  -  -  -  -  -  -  -  Pericrocotus igneus  -  -  -  -  -  Timaliidae  -  -  -  -  -  -  Pomatorhinus  -  -  -  -  -  -  -  Pomatorhinus montanus  -  -  -  -  -  -  Cyanoderma  -  -  -  -  -  -  -  Cyanoderma erythropterum  -  -  -  -  -  -  -  Cyanoderma rufifrons  -  -  -  -  -  -  Stachyris  -  -  -  -  -  -  -  Stachyris maculata  -  -  -  -  -  -  -  Stachyris poliocephala  -  -  -  -  -  -  Macronus  -  -  -  -  -  -  -  Macronus ptilosus  -  -  -  -  -  -  Mixornis  -  -  -  -  -  -  -  Mixornis bornensis  -  -  -  -  -  Eurylaimidae  -  -  -  -  -  -  Eurylaimus  -  -  -  -  -  -  -  Eurylaimus javanicus  -  -  -  -  -  -  -  Eurylaimus ochromalus  -  -  -  -  -  -  Calyptomena  -  -  -  -  -  -  -  Calyptomena viridis  -  -  -  -  -  -  Cymbirhynchus  -  -  -  -  -  -  -  Cymbirhynchus macrorhynchos  -  -  -  -  -  -  Corydon  -  -  -  -  -  -  -  Corydon sumatranus  -  -  -  -  -  Dicruridae  -  -  -  -  -  -  Dicrurus  -  -  -  -  -  -  -  Dicrurus aeneus  -  -  -  -  -  -  -  Dicrurus paradiseus  -  -  -  -  -  Estrildidae  -  -  -  -  -  -  Lonchura  -  -  -  -  -  -  -  Lonchura atricapilla  -  -  -  -  -  Pycnonotidae  -  -  -  -  -  -  Pycnonotus  -  -  -  -  -  -  -  Pycnonotus brunneus  -  -  -  -  -  -  -  Pycnonotus atriceps  -  -  -  -  -  -  -  Pycnonotus simplex  -  -  -  -  -  -  -  Pycnonotus eutilotus  -  -  -  -  -  -  -  Pycnonotus erythropthalmos  -  -  -  -  -  -  -  Pycnonotus goiavier  -  -  -  -  -  Chloropseidae  -  -  -  -  -  -  Chloropsis  -  -  -  -  -  -  -  Chloropsis sonnerati  -  -  -  -  -  -  -  Chloropsis cyanopogon  -  -  -  -  -  Nectariniidae  -  -  -  -  -  -  Aethopyga  -  -  -  -  -  -  -  Aethopyga siparaja  -  -  -  -  -  -  Anthreptes  -  -  -  -  -  -  -  Anthreptes malacensis  -  -  -  -  -  -  -  Anthreptes simplex  -  -  -  -  -  -  Arachnothera  -  -  -  -  -  -  -  Arachnothera everetti  -  -  -  -  -  -  -  Arachnothera longirostra  -  -  -  -  -  -  -  Arachnothera robusta  -  -  -  -  -  -  -  Arachnothera flavigaster  -  -  -  -  -  -  Kurochkinegramma  -  -  -  -  -  -  -  Kurochkinegramma hypogrammicum  -  -  -  -  -  Irenidae  -  -  -  -  -  -  Irena  -  -  -  -  -  -  -  Irena puella  -  -  -  -  -  Pittidae  -  -  -  -  -  -  Erythropitta  -  -  -  -  -  -  -  Erythropitta ussheri  -  -  -  -  -  -  Pitta  -  -  -  -  -  -  -  Pitta sordida  -  -  -  -  -  Monarchidae  -  -  -  -  -  -  Hypothymis  -  -  -  -  -  -  -  Hypothymis azurea  -  -  -  -  -  -  Terpsiphone  -  -  -  -  -  -  -  Terpsiphone paradisi  -  -  -  -  Trogoniformes  -  -  -  -  -  Trogonidae  -  -  -  -  -  -  Harpactes  -  -  -  -  -  -  -  Harpactes diardii  -  -  -  -  -  -  -  Harpactes kasumba  -  -  -  -  -  -  -  Harpactes duvaucelii  -  -  -  -  Cuculiformes  -  -  -  -  -  Cuculidae  -  -  -  -  -  -  Chrysococcyx  -  -  -  -  -  -  -  Chrysococcyx xanthorhynchus  -  -  -  -  -  -  Centropus  -  -  -  -  -  -  -  Centropus rectunguis  -  -  -  -  -  -  Cacomantis  -  -  -  -  -  -  -  Cacomantis sonneratii  -  -  -  -  -  -  -  Cacomantis merulinus  -  -  -  -  -  -  Rhinortha  -  -  -  -  -  -  -  Rhinortha chlorophaea  -  -  -  -  Bucerotiformes  -  -  -  -  -  Bucerotidae  -  -  -  -  -  -  Berenicornis  -  -  -  -  -  -  -  Berenicornis comatus  -  -  -  -  -  -  Anorrhinus  -  -  -  -  -  -  -  Anorrhinus galeritus  -  -  -  -  -  -  Rhyticeros  -  -  -  -  -  -  -  Rhyticeros undulatus  -  -  -  -  -  -  Buceros  -  -  -  -  -  -  -  Buceros rhinoceros  -  -  -  -  -  -  Rhinoplax  -  -  -  -  -  -  -  Rhinoplax vigil  -  -  -  -  Hydrornis  -  -  -  -  -  Hydrornis baudii  -  -  -  -  -  Hydrornis schwaneri