All posts by kylewtomlinson@gmail.com

New paper out

Ratnam J*, Tomlinson KW*, Rasquinha DN & Sankaran M. 2016. Savannahs in Asia: evidence for antiquity, biogeography, and an uncertain future. Philosophical Transactions of the Royal Society B 371. (*Joint First Author)

http://rstb.royalsocietypublishing.org/content/371/1703/20150305.

Abstract: The savannahs of Asia remain locally unrecognized as distinctive ecosystems, and continue to be viewed as degraded forests or seasonally dry tropical forests. These colonial-era legacies are problematic, because they fail to recognize the unique diversity of Asian savannahs and the critical roles of fire and herbivory maintaining ecosystem health and diversity. In this review, we show: the palaeo-historical evidence suggests that the savannahs of Asia have existed for at least 1 million years, long before widespread landscape modification by humans; savannah regions across Asia have levels of C4 grass endemism and diversity that are consistent with area-based expectations for non-Asian savannahs; there are at least three distinct Asian savannah communities, namely deciduous broadleaf savannahs, deciduous fine-leafed and spiny savannahs and evergreen pine savannahs, with distinct functional ecologies consistent with fire- and herbivory-driven community assembly. Via an analysis of savannah climate domains on other continents, we map the potential extent of savannahs across Asia. We find that the climates of African savannahs provide the closest analogues for those of Asian deciduous savannahs, but that Asian pine savannahs occur in climates different to any of the savannahs in the southern continents. Finally, we review major threats to the persistence of savannahs in Asia, including the mismanagement of fire and herbivory, alien woody encroachment, afforestation policies and future climate uncertainty associated with the changing Asian monsoon. Research agendas that target these issues are urgently needed to manage and conserve these ecosystems.

This article is part of the themed issue ‘Tropical grassy biomes: linking ecology, human use and conservation’.

http://rstb.royalsocietypublishing.org/content/371/1703#articles

New Paper out

Monoy et al. Temporal changes in tree species and trait composition in a cyclone-prone Pacific dipterocarp forest. Ecosystems. 

http://link.springer.com/article/10.1007/s10021-016-9983-0/fulltext.html

Abstract: Our understanding of the effects of tropical cyclones on species composition and dynamics of forest communities is mainly derived from studies that have considered single cyclonic events. Here we examined changes in the tree species and functional trait composition in an 8-ha Dipterocarp forest at Palanan in the northeastern Philippines that is subject to a high frequency of cyclonic disturbance (1–4 cyclones annually). The plot has been censused four times over a 16-year interval allowing us to consider the medium-term forest dynamics in response to repeated cyclones. We hypothesized that as the forest community in Palanan has been selected under frequent disturbance by cyclones, it should show little functional change across the census intervals. We analyzed changes in demography, species composition, and community-weighted functional traits (specific leaf area, leaf area, wood density, and specific growth rate) across the censuses and compared these against cyclone intensities during the census intervals. Demographic changes across census years suggest that the community responded to cyclonic disturbances through substantial turnover in the small- and medium-size individuals, and that there has been an increase in plot-level stem density and basal area across the measured period. Trait compositional changes from 1994 to 2010 were mostly small, but indicate a shift towards species with larger leaves and faster growth rates—traits that are associated with fast recovery after disturbance. These changes all coincide with a large intense cyclone between the second and third censuses, suggesting that cyclone strength, more than cyclone frequency, affects this forest.

 

New paper out

Beng et al. 2016. The utility of DNA metabarcoding for studying the response of arthropod diversity and composition to land-use change in the tropics. Scientific Reports.            http://www.nature.com/articles/srep24965

Abstract: Metabarcoding potentially offers a rapid and cheap method of monitoring biodiversity, but real-world applications are few. We investigated its utility in studying patterns of litter arthropod diversity and composition in the tropics. We collected litter arthropods from 35 matched forest-plantation sites across Xishuangbanna, southwestern China. A new primer combination and the MiSeq platform were used to amplify and sequence a wide variety of litter arthropods using simulated and real-world communities. Quality filtered reads were clustered into 3,624 MOTUs at ≥97% similarity and the taxonomy of each MOTU was predicted. We compared diversity and compositional differences between forests and plantations (rubber and tea) for all MOTUs and for eight arthropod groups. We obtained ~100% detection rate after in silico sequencing six mock communities with known arthropod composition. Ordination showed that rubber, tea and forest communities formed distinct clusters. α-diversity declined significantly between forests and adjacent plantations for more arthropod groups in rubber than tea, and diversity of order Orthoptera increased significantly in tea. Turnover was higher in forests than plantations, but patterns differed among groups. Metabarcoding is useful for quantifying diversity patterns of arthropods under different land-uses and the MiSeq platform is effective for arthropod metabarcoding in the tropics.

New paper out

Sreekar et al. 2016. Effects of forests, roads and mistletoe on bird diversity in monoculture rubber plantations. Scientific Reports.   http://www.nature.com/articles/srep21822

Abstract: Rising global demand for natural rubber is expanding monoculture rubber (Hevea brasilensis) at the expense of natural forests in the Old World tropics. Conversion of forests into rubber plantations has a devastating impact on biodiversity and we have yet to identify management strategies that can mitigate this. We determined the life-history traits that best predict bird species occurrence in rubber plantations in SW China and investigated the effects of surrounding forest cover and distance to roads on bird diversity. Mistletoes provide nectar and fruit resources in rubber so we examined mistletoe densities and the relationship with forest cover and rubber tree diameter. In rubber plantations, we recorded less than half of all bird species extant in the surrounding area. Birds with wider habitat breadths and low conservation value had a higher probability of occurrence. Species richness and diversity increased logarithmically with surrounding forest cover, but roads had little effect. Mistletoe density increased exponentially with rubber tree diameters, but was unrelated to forest cover. To maximize bird diversity in rubber-dominated landscapes it is therefore necessary to preserve as much forest as possible, construct roads through plantations and not forest, and retain some large rubber trees with mistletoes during crop rotations.

Huang Guohualing and (honorary lab member) Sreekar Rachakonda outstandingly defend their MSc theses

Congratulations to Guohualing and Sreekar who both received ‘excellent’ evaluations for their MSc theses, defended on 3 December.  Great going guys!

Thanks to the examination committee for taking the time to review Jiajia and Lingling’s theses, and especially to Dr Eben Goodale and Dr Rhett Harrison for travelling to  Xishuangbanna to participate in the theses defences.

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Jiajia Liu and Lingling Shi successfully defend their PhD theses

Congratulations to Jiajia and Lingling who both gave very interesting presentations to a packed room and faced down a tough and probing defence committee.  We are all very proud of you and wish you much success in your future academic careers.

A big thank you to the examination committee for taking the time to review Jiajia and Lingling’s theses, and especially to Dr Ferry Slik (Jiajia’s supervisor and Lingling’s mentor) for making the journey from Brunei for the defences.

Lingling and Jiajia after the ceremony.
Lingling and Jiajia after the confirmation ceremony. The batik shirts were presents from Ferry and his wife Sumi.

 

 

 

 

 

 

 

 

 

Jiajia Liu, Ferry Slik and Lingling Shi.
Jiajia Liu, Ferry Slik and Lingling Shi.

 

Jiajia and Lingling with the defence committee and supervisors.
Jiajia and Lingling with the defence committee and supervisors.

 

 

 

 

 

 

 

 

 

 

 

Jiajia and Lingling with the rest of the lab
Jiajia and Lingling with the rest of the lab