Spatial and temporal distribution dataset of benthic macroalgae during the 2015-2016 tropical monsoonal cycle in Malaysia

Abstract Background The effects of small-scale disturbances, such as monsoon, are understudied in tropical regions. The storms associated with monsoon events not only modify the local macroalgal community structure, but also reveal the continuation of short-term recolonisation. Thus, this study aims to determine the variation in species, assemblage and cover of macroalgae during the monsoonal cycle from 2015 to 2016. This paper presents data on the spatial and temporal distribution of benthic macroalgae along the coastline of Johor, Malaysia. The information is presented as raw and partially-processed data, which summarises the cover and frequency of macroalgae at the respective study sites. This paper describes an important set of data that can be used further for in-situ experiments on the effects of environmental disturbances towards pioneer and climax species in tropical areas. New information This study provides a description of the east coast shore of Peninsular Malaysia, specifically in Johor coast in 2015-2016. The spatial and temporal distribution and abundance of a total of 41 taxa were assessed at four monsoon-exposed locations. These data provide a comprehensive baseline against disturbance and recolonisation of macroalgal community can be effectively and objectively evaluated.


Introduction
Environmental stress, such as disturbance, occurs over a short period of time and results in significant changes in the ecosystem. Many ecosystems and species evolve in response to particular environmental disturbances that create patches of disturbed habitat and play a significant role in controlling such things as life cycles, food, nutrient supply and habitat availability (Kroeker et al. 2020). Community structure in the disturbed area creates variability at spatial and temporal scales, including in terrestrial, freshwater and marine ecosystems (Turner 2010). In Malaysia, monsoonal storms are the primary annual storms associated with local changes in rainfall, wave, current and wind speed intensities (Satari et al. 2015). Monsoonal storm activities, such as wave impact, heavy winds and strong currents affect the eastern coast of Peninsular Malaysia, specifically Johor which is located in the southern region of Peninsular Malaysia. The coastline features vary from being very exposed to very sheltered and, therefore, impact the delicate marine macrophytes that reside along the coastline, such as macroalgae (Lindenmayer and Fischer 2007).
The existence of macroalgae is usually species-specific as most species require specific conditions for colonising their respective habitats (Zainee et al. 2019b). Dominant macroalgal species can be found attached to any available substrate including in water puddles on the surface of artificial substrate, such as sea wall rocks (Zainee et al. 2019a). However, the effect of monsoon reduces the macroalgal productivity through modification and destruction of their habitat (Kim et al. 2017). These events will not only pull away the early coloniser, fleshy and delicate macroalgal (such as Chaetomorpa spp.), but also affect the climax macroalgal community that have strongly-attached holdfasts, such as Sargassum (Zainee and Rozaimi 2020). Once the actual disturbance event is finished, the succession process begins and favours those that are opportunistic in nature (e.g. Suding et al. 2004), which may eventually produce a similar ecosystem to the one that existed prior to the monsoon disturbance. Some of the disturbances events relating to macroalgal community are those related to small scale environmental events in general (e.g. Kendrick et al. 2004, Kim et al. 2017, Prathep et al. 2008, whereas others are specific to large scale disturbances such as hurricane and tsunami (Prathep et al. 2008, Wilson et al. 2020).
Therefore, more comprehensive studies are needed to obtain data on the impacts of monsoons on the macroalgal community.
Thus, this data paper presents the dataset on the immediate impact of monsoon on the eastern coast of Johor. The temporal and spatial data include the changes in cover and frequency of benthic macroalgae in the area, demonstrating variation in macroalgae diversity over the 14-months study period. Such data allow further in-situ experiments on the effect of environmental disturbances towards pioneer and climax species. Besides, substratum-and habitat-specificity of the macroalgae species is presented, which allows insights into assessing macroalgal abundances. In conclusion, the data serve as part of a larger assessment effort and the dataset synthesises the results of macroalgal diversity work done in the eastern coastal waters of Johor (Malaysia).

Project description
Title: Spatial and temporal distribution dataset of benthic macroalgae during the 2015-2016 tropical monsoonal cycle in Malaysia Sampling methods Study extent: Sampling activity was conducted in four locations in the eastern Johor coastline: Pantai Pasir Lanun, Pulau Mawar, Telok Gorek and Tanjung Lompat (Fig. 1). Pantai Pasir Lanun is located at the tip of a foreland with a relatively straight coastline, predominantly featuring hard substrates composed of large areas of coral rubble and boulders. Pulau Mawar is characterised by a shallow-elevated sandy terrain with small patches of mangrove trees and coral rubble. Telok Gorek is located within an indented bay, covered with mangrove trees and sheltered from the foreland. Tanjung Lompat consists of a foreland and an extensive bay, characterised by boulder-pebbles on the foreland and a shallow sandy bay.
Sampling description: Sampling was undertaken from January 2015 until February 2016 during the lowest tide of the month (Table 1). Transects were placed randomly, taken to represent the macroalgae cover and frequency at each site. The quadrats were placed alternately at every 1 metre of the 25-metre transect line. Initially, the macroalgae that were found inside the quadrat were recorded, identified and inventoried according to the type of species, percentage of cover and percentage of frequency (Suppl. material 1). The types of substratum attached by macroalgae were noted as representing the habitat specificity of the macroalgae ( Table 2). The raw data of cover and frequency were calculated by multiplying the vertical count of every species to the five levels of multiplier and the total number of sub-quadrat from the nine transect lines with a total of 234 quadrats (Suppl. materials 2, 3, 4, 5). The cover of every species of macroalgae was then analysed by summing the percentage cover value of prostrate and erect parts of the macroalgae in each sub-quadrat (10 cm × 10 cm) after Saito and Atobe (1970) (Suppl. material 6). The percentage frequency of macroalgae was obtained by calculating the total number of squares (q ) in which the species occurred, divided by the total number of small squares in the quadrat (= 25) and multiplied by 100 (Suppl. materials 2, 3, 4, 5). A pre-analytical view of the percentage cover and frequency data of macroalgae is visualised in Fig. 2    Quality control: All scientific names are morphologically identified according to Ismail (1995), Trono and Ganzon-Fortes (1988), Zainee et al. (2018) and Zainee et al. (2019a) and are standardised according to Guiry and Guiry (2021) and WoRMS Editorial Board (2021).
In-situ identification of species and destructive collection for first-time observed samples and preservation in formaldehyde, 2.
Non-destructive sampling (except for filamentous algae that need microscopic observation in the laboratory) at four study sites, 3.
Photography, sorting, cleaning and preparation of herbarium specimens, 4.
Conversion of paper-based records from the field and laboratory into an electronic data format (Excel spreadsheets), 5.
Organising the datasets into a standardised format, 6.
Standardisation of taxonomy using the World Register of Marine Species and AlgaeBase,

7.
Export of data as a DarwinCore Archive and 8.
Generation of dataset-level metadata.

Geographic coverage
Description: Sampling was undertaken along four major shore stretches of the entire coast of east Johor, covering approximately 180 km from Desaru to Mersing. The eastern coast of Johor extends approximately 175 km from Teluk Lipat (i.e. Lipat Bay) to the north and Teluk Ramunia to the south.

Taxonomic coverage
Description: We report the identification of marine algae species from rhodophytes, chlorophytes and phaeophytes.

IP rights notes:
To the extent possible under law, the publisher has waived all rights to these data and has dedicated them to the Open Data Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and sources are credited. Description: This data paper presents the dataset on the inventory of macroalgae during the monsoonal storm cycle of 2015-2016 at the selected sites along the eastern coast of Johor, Malaysia. In particular, we focused on recording the occurrence of every species at the selected sites over the 14-months study period. Besides, substratumand habitat-specificity of the macroalgae species is presented, which allows insights into assessing macroalgal abundances. In conclusion, the data serve as part of a larger assessment effort and the dataset synthesises the results of macroalgal diversity work done in the eastern coastal waters of Johor (Malaysia). The full name, with authorship and date information, if known, of the direct, most proximate higher-rank parent taxon (in a classification) of the most specific element of the scientificName.

Data resources
kingdom The full scientific name of the kingdom in which the taxon is classified. phylum The full scientific name of the phylum or division in which the taxon is classified.

class
The full scientific name of the class in which the taxon is classified. order The full scientific name of the order in which the taxon is classified. family The full scientific name of the family in which the taxon is classified. taxonRank The taxonomic rank of the most specific name in the scientificName.
scientificNameAuthorship The authorship information for the scientificName formatted according to the conventions of the applicable nomenclaturalCode.
taxonomicStatus The status of the use of the scientificName as a label for a taxon.

lifeStage
The age class or life stage of the Organisms at the time the Occurrence was recorded. reproductiveCondition The reproductive condition of the biological individuals is represented in Occurrence.