Inter- and Intra-specific variability in functional traits of seedlings planted in successional tropical dry forest
The dry tropical forests are among the most threatened ecosystems in the world; they have been degraded and removed due to commercial values and cattle ranges. Restoration projects have gained global importance, including in Costa Rica where large restoration efforts have been started since 1970s. H...
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| Formato: | H2 |
| Lenguaje: | Inglés sueco |
| Publicado: |
SLU/Southern Swedish Forest Research Centre
2016
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| Materias: |
| _version_ | 1855571433613164544 |
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| author | Söderlund, Stina |
| author_browse | Söderlund, Stina |
| author_facet | Söderlund, Stina |
| author_sort | Söderlund, Stina |
| collection | Epsilon Archive for Student Projects |
| description | The dry tropical forests are among the most threatened ecosystems in the world; they have been degraded and removed due to commercial values and cattle ranges. Restoration projects have gained global importance, including in Costa Rica where large restoration efforts have been started since 1970s. However, previous restoration projects have scored limited success in several areas due to species mismatch with the prevailing site conditions. Thus, trait-based approach has been emerged as a way to identify candidate species for restoration. A trait is a morphological, anatomical, biochemical, physiological and/or phenological feature measurable at the individual level; whereas a functional trait is any trait which impacts fitness indirectly by its effects on growth, reproduction and survival. The aims of the study were to examine variation in traits within (intra-specific) and between (inter-specific) species in relation to above- (light) and below-ground (nutrient and water) resources; and if functional traits are good predictors of survival and growth of planted seedlings of four tree species, Astronium graveolens (RonRon), Dalbergia retusa (Cocobolo), Hymenaea courbaril (Guapinol), and Thouinidium decandrum (Sardino). For this purpose, a factorial experiment involving two levels of forest type (old versus young) and trenching (with versus without) was established in the forest experimental station, Horizontes, a part of Conservation area of Guanacaste. There were four plots in each forest type, and four seedlings of each species were planted in May 2013 in each sub-plot. Leaf- and stem functional traits and survival rate were assessed two years post-planting while root collar diameter and height of seedlings were recorded for two consecutive years post-planting. Two-way analysis of variance (ANOVA) was performed to determine significant differences in intra-specific trait variabilities while three-way ANOVA was performed to determine differences in traits and seedling performance among species and treatments. To examine whether traits can predict field performance of planted seedlings, correlation analyses were performed between traits and seedling growth variables.
The results showed that intra-specific leaf and stem traits did not vary significantly between forest types and trenching treatment for all the studied species, except A. graveolens for which specific leaf area was significantly higher (p = 0.015) for seedlings planted under old- than young forest. Three-way ANOVA showed highly significant differences in leaf- and stem traits among species (p < 0.01), except stem dry matter content (p = 0.209). Leaf thickness, leaf dry matter content and specific leaf area did also significantly vary between forest types (p < 0.05) but not between trenching treatments and interactions between species, forest type and trenching treatments. The mean stem specific density, leaf dry matter content and leaf density were lower while specific leaf area was higher for D. retusa than other species. H. courbaril had higher leaf thickness than the rest of the species. For A. graveolens and T. decandrum, stem specific density, specific leaf area, leaf dry matter content and leaf density did not differ significantly. Among the traits analysed, leaf thickness and leaf dry matter content were significantly higher for seedlings planted in young- than old forest; whereas specific leaf area was significantly lower for seedlings planted in young- than old forest. The trenching treatment (with versus without) had no effect on inter-specific traits.
The correlation between inter-specific traits and seedling growth was significant for most of the traits analysed. Seedling height and root collar diameter during the first two years post-planting significantly and positively correlated with leaf thickness and negatively with specific leaf area. The current annual increment in height (CAIH) and root collar diameter (CAID) were positively correlated with leaf density and leaf dry matter content but negatively correlated with specific leaf area. Correlation analysis between intra-specific traits and seedling growth was also performed; and significant correlation was found between leaf thickness and stem dry matter content with seedling growth in three out of four species; especially leaf thickness was correlated with both diameter and height growth of two out of four species.
In conclusion, this study highlights the importance of functional traits when looking on survival and growth of different species in different environmental conditions. This new trait-based approach is shown to predict survival and growth and thereby can be used as a possible guide for future restoration projects in similar climatic- and environmental conditions. As sample sizes were few in the present study, I recommend further research using larger sample size for each treatment (sub-plot) and more species to be able to identify the best predictive traits. |
| format | H2 |
| id | RepoSLU8937 |
| institution | Swedish University of Agricultural Sciences |
| language | Inglés swe |
| publishDate | 2016 |
| publishDateSort | 2016 |
| publisher | SLU/Southern Swedish Forest Research Centre |
| publisherStr | SLU/Southern Swedish Forest Research Centre |
| record_format | eprints |
| spelling | RepoSLU89372016-04-20T07:54:33Z Inter- and Intra-specific variability in functional traits of seedlings planted in successional tropical dry forest Do functional traits predict survival and growth of planted seedlings? Söderlund, Stina functional traits leaf traits restoration stem traits tropical Dry Forests The dry tropical forests are among the most threatened ecosystems in the world; they have been degraded and removed due to commercial values and cattle ranges. Restoration projects have gained global importance, including in Costa Rica where large restoration efforts have been started since 1970s. However, previous restoration projects have scored limited success in several areas due to species mismatch with the prevailing site conditions. Thus, trait-based approach has been emerged as a way to identify candidate species for restoration. A trait is a morphological, anatomical, biochemical, physiological and/or phenological feature measurable at the individual level; whereas a functional trait is any trait which impacts fitness indirectly by its effects on growth, reproduction and survival. The aims of the study were to examine variation in traits within (intra-specific) and between (inter-specific) species in relation to above- (light) and below-ground (nutrient and water) resources; and if functional traits are good predictors of survival and growth of planted seedlings of four tree species, Astronium graveolens (RonRon), Dalbergia retusa (Cocobolo), Hymenaea courbaril (Guapinol), and Thouinidium decandrum (Sardino). For this purpose, a factorial experiment involving two levels of forest type (old versus young) and trenching (with versus without) was established in the forest experimental station, Horizontes, a part of Conservation area of Guanacaste. There were four plots in each forest type, and four seedlings of each species were planted in May 2013 in each sub-plot. Leaf- and stem functional traits and survival rate were assessed two years post-planting while root collar diameter and height of seedlings were recorded for two consecutive years post-planting. Two-way analysis of variance (ANOVA) was performed to determine significant differences in intra-specific trait variabilities while three-way ANOVA was performed to determine differences in traits and seedling performance among species and treatments. To examine whether traits can predict field performance of planted seedlings, correlation analyses were performed between traits and seedling growth variables. The results showed that intra-specific leaf and stem traits did not vary significantly between forest types and trenching treatment for all the studied species, except A. graveolens for which specific leaf area was significantly higher (p = 0.015) for seedlings planted under old- than young forest. Three-way ANOVA showed highly significant differences in leaf- and stem traits among species (p < 0.01), except stem dry matter content (p = 0.209). Leaf thickness, leaf dry matter content and specific leaf area did also significantly vary between forest types (p < 0.05) but not between trenching treatments and interactions between species, forest type and trenching treatments. The mean stem specific density, leaf dry matter content and leaf density were lower while specific leaf area was higher for D. retusa than other species. H. courbaril had higher leaf thickness than the rest of the species. For A. graveolens and T. decandrum, stem specific density, specific leaf area, leaf dry matter content and leaf density did not differ significantly. Among the traits analysed, leaf thickness and leaf dry matter content were significantly higher for seedlings planted in young- than old forest; whereas specific leaf area was significantly lower for seedlings planted in young- than old forest. The trenching treatment (with versus without) had no effect on inter-specific traits. The correlation between inter-specific traits and seedling growth was significant for most of the traits analysed. Seedling height and root collar diameter during the first two years post-planting significantly and positively correlated with leaf thickness and negatively with specific leaf area. The current annual increment in height (CAIH) and root collar diameter (CAID) were positively correlated with leaf density and leaf dry matter content but negatively correlated with specific leaf area. Correlation analysis between intra-specific traits and seedling growth was also performed; and significant correlation was found between leaf thickness and stem dry matter content with seedling growth in three out of four species; especially leaf thickness was correlated with both diameter and height growth of two out of four species. In conclusion, this study highlights the importance of functional traits when looking on survival and growth of different species in different environmental conditions. This new trait-based approach is shown to predict survival and growth and thereby can be used as a possible guide for future restoration projects in similar climatic- and environmental conditions. As sample sizes were few in the present study, I recommend further research using larger sample size for each treatment (sub-plot) and more species to be able to identify the best predictive traits. Den tropiska torrskogen är en av de mest hotade ekosystemen i världen. De har degraderats och arealen minskar på grund av skogarnas kommersiella värden, ökad odling av jordbruksgrödor och boskapsskötsel. Restaureringsprojekt har fått global betydelse, däribland i Costa Rica där stora restaureringsinsatser inleddes på 1970-talet. Emellertid har restaureringsprojekten visat begränsad framgång inom flera områden på grund av att använda arter varit i obalans med rådande förhållanden på platsen. Sålunda har ett egenskaps-baserat tillvägagångssätt vuxit fram som ett sätt att identifiera kandidatarter för restaurering. Egenskaper av betydelse i sammanhanget kan vara morfologiska, anatomiska, biokemiska, fysiologiska och fenologiska, mätbara på individnivå. En funktionell egenskap är en egenskap som påverkar lämpligheten indirekt genom dess effekter på tillväxt, reproduktion och överlevnad. Syftet med studien var att undersöka variationer i egenskaper inom arten (intra-specifik) och mellan arter (inter-specifika) i förhållande till ovanjordiska- (ljus) och underjordiska (näringsämnen och vatten) resurser, samt om de funktionella egenskaperna är goda prediktorer för överlevnad och tillväxt av planterade plantor av fyra trädslag, Astronium graveolens (Ronron), Dalbergia retusa (Cocobolo), Hymenaea courbaril (Guapinol), och Thouinidium decandrum (Sardino). För detta ändamål lades ett faktorsexperiment ut i två skogstyper (gammal eller ung), med eller utan rotisolering (diken) i försöksskogar i Horizontes, en del av ett naturvårdsområde i Guanacaste, Costa Rica. På fyra ytor i varje skogstyp planterades fyra plantor av varje art i maj 2013. Blad- och stamfunktionella egenskaper och överlevnad mättes två år efter plantering och rothalsdiameter och höjd mättes varje år under två år efter plantering. Två-vägs variansanalys (ANOVA) användes för att beräkna skillnader i variation i inomartsspecifika egenskaper, och trevägs ANOVA användes för att beräkna skillnader i variation i egenskaper mellan arter och behandlingar. För att undersöka om egenskaper kan förutsäga överlevnad och tillväxt i fält för planterade plantor utfördes korrelationsanalyser mellan egenskaper och tillväxtvariabler. Resultaten visar att inomartsspecifika blad- och stamegenskaper inte varierar signifikant mellan skogstyper och dikningsbehandlingar för alla studerade arter, förutom för A. graveolens för vilken den specifika bladytan var signifikant högre (p = 0,015) för plantor planterade i den äldre skogstypen än i ungskog. Trevägs ANOVA visade starka signifikanta skillnader i blad- och stamegenskaper mellan arter (p <0,01), förutom stamtorrsubstanshalt (p = 0,209). Bladtjocklek, bladtorrsubstanshalt och specifik bladyta varierade signifikant mellan skogstyper (p <0,05), men inte mellan dikningsbehandlingar och interaktioner mellan arter, skogstyp och dikningsbehandlingar. Medelvärdet för stamspecifik densitet, bladtorrsubstanshalt och bladdensitet var lägre medan specifika bladytan var högre för D. retusa jämfört med de andra arterna. H. courbaril hade högre bladtjocklek än övriga arter. Stamspecifik densitet, specifik bladyta, bladtorrsubstanshalt och bladtäthet skilde sig inte signifikant mellan A. graveolens och T. decandrum. Bland de egenskaper som analyserades, var bladtjocklek och bladtorrsubstanshalt betydligt högre för plantor planterade i ung skog än i gammal skog, emedan specifik bladyta var signifikant lägre för plantor planterade i ung 5 skog jämfört med gammal skog. Rotisoleringsbehandling (med eller utan dike) hade ingen effekt på mellanarts-specifika egenskaper. Korrelationen mellan inter-specifika egenskaper och planttillväxt var signifikant för de flesta av egenskaperna som analyserades. Planthöjd och rothalsdiameter under de två första åren efter plantering var signifikant- och positivt korrelerat med bladtjocklek och negativt med specifik bladyta. Den nuvarande årliga tillväxten i höjd (CAIH) och rothalsdiameter (CAID) var positivt korrelerad med bladdensitet och bladtorrsubstanshalt men negativt korrelerad med specifik bladyta. Korrelationsanalys mellan intra-specifika egenskaper och planttillväxt utfördes också och visar på signifikant korrelation mellan bladtjocklek och stamtorrsubstanshalt med planttillväxt i tre av fyra arter, särskilt var bladtjocklek korrelerad med både diameter och höjdtillväxt av två av fyra arter. Sammanfattningsvis belyser denna studie vikten av funktionella egenskaper vid analys av överlevnad och tillväxt av olika arter under olika miljöförhållanden. Detta nya egenskapsbaserade tillvägagångssätt kan förutsäga överlevnad och tillväxt och därmed användas som vägledning för framtida restaureringsprojekt under liknande klimat- och miljöförhållanden. Eftersom storleken på den aktuella studien var i minsta laget, rekommenderar jag ytterligare forskning med större prov-storlekar för varje behandling samt flera arter för att på så sätt kunna identifiera de bästa prediktiva egenskaperna. SLU/Southern Swedish Forest Research Centre 2016 H2 eng swe https://stud.epsilon.slu.se/8937/ |
| spellingShingle | functional traits leaf traits restoration stem traits tropical Dry Forests Söderlund, Stina Inter- and Intra-specific variability in functional traits of seedlings planted in successional tropical dry forest |
| title | Inter- and Intra-specific variability in functional traits
of seedlings planted in successional tropical dry forest |
| title_full | Inter- and Intra-specific variability in functional traits
of seedlings planted in successional tropical dry forest |
| title_fullStr | Inter- and Intra-specific variability in functional traits
of seedlings planted in successional tropical dry forest |
| title_full_unstemmed | Inter- and Intra-specific variability in functional traits
of seedlings planted in successional tropical dry forest |
| title_short | Inter- and Intra-specific variability in functional traits
of seedlings planted in successional tropical dry forest |
| title_sort | inter- and intra-specific variability in functional traits
of seedlings planted in successional tropical dry forest |
| topic | functional traits leaf traits restoration stem traits tropical Dry Forests |