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The freshwater calanoid copepod Arctodiaptomus dorsalis (Marsh, 1907) was first recorded from the Philippines in 2001 in Laguna de BayThe copepod gained the status of "invasive species" in 2021 due to its presence in 23 of 32 surveyed Philippine lakes and rivers. Genomic DNA was extracted from 107 individuals of A. dorsalis , representing seven populations on the island of Luzon to gather information on the population structure, genetic connectivity, and range expansion of the species.. A 720-bp fragment of the nuclear ITS1 and ITS2 spacers was used to analyze the genetic structure of the populations. High haplotype diversity (Hd = 0.7951), low nucleotide diversity (π = 0.0024), and low genetic distance between populations indicate high levels of gene flow and low levels of isolation. Six of the 12 haplotypes were unique to particular sites, but the three shared haplotypes suggest panmixia among populations. Tajima's D (D = 0.4945) and Fu's F (F = -2.8950) suggest a recent increase in population size following a bottleneck. This may have occurred as the result of the copepod's suspected initial introduction into the Philippines after 1905 via the trade in ornamental aquarium fish, eventually followed by its expansion into nearby inland waters through one or more aquaculture-mediated introduction events. Laguna de Bay's role since 1972 as the main source of tilapia fingerlings (Oreochromis niloticus (Linnaeus, 1758)) for release into various Philippine lakes provides circumstantial support for this scenario. [ABSTRACT FROM AUTHOR]

A floristic study of the diatoms (Bacillariophyceae) along the Marikina River in the eastern part of Metro Manila, Philippines, recorded at least 140 species belonging to 39 genera. Of these genera, one of the greatest number of species was observed in the genus Gomphonema (18 species). These species were identified and described under the bright field light microscope. Some species were further observed under the scanning electron microscope. A habitat description of the occurrence of the Gomphonema species is given. Twelve (12) out of the 18 species are new records for the country: G. brasiliense subsp. pacificum Moser, Lange-Bertalot & Metzeltin, G. chinense Liu & Kociolek, G. contraturris Lange-Bertalot & E.Reichardt, G. cuneolus E.Reichardt, G. exilissimum (Grunow) Lange-Bertalot & E.Reichardt, G. insigniforme E.Reichardt & Lange-Bertalot, G. javanicum Hustedt, G. kobayasii Kociolek & J.C.Kingston, G. pseudosphaerophorum H. Kobayasi, G. sundaense E.Reichardt, G. cf. qingyiensis L-X Zhang, P. Yu & Q-M You, and G. vibrio var. bohemicum (Reichelt & Fricke) R. Ross. Hence, this paper reports a total of 44 species of Gomphonema from the Philippines, including previous studies from 1937 to date. [ABSTRACT FROM AUTHOR]

Monitoring the ecological integrity of streams is a challenge, especially in the tropics, which experience high rates of degradation. Multimetric scoring systems have been widely used in other countries in evaluating current stream conditions; however, it has never been done in the Philippines. This study focuses on the development of a benthic macroinvertebrate-based multimetric index for the overall assessment of streams in Mt. Apo, Mindanao, Philippines. The index was used to develop existing physicochemical and biological data obtained during 2010 to 2015 surveys from 15 monitoring sites within the Mt. Apo Geothermal Project (MAGP). Metrics related to benthic macroinvertebrate abundance, richness, composition, functional habit groups, functional feeding groups, and pollution tolerance were screened for their range, temporal stability, sensitivity, discrimination efficiency (DE), redundancy, and responsiveness to anthropogenic impacts. The resulting multimetric index, the Mt. Apo Biotic Index (MABI), is computed as the sum of the individual metric scores after metric transformation using the discrete scoring method DRQ1 (D = discrete, R = reference, Q1 = 25th percentile) of the six core metrics: (1) number of Coleoptera individuals (abundance), (2) number of taxa (richness); (3) [%] Coleoptera taxa (composition), (4) number of sprawler individuals (functional habit group), (5) [%] collector-filterer taxa (functional feeding group), and (6) the Biological Monitoring Working Party Thai version (BMWP-Thai; pollution tolerance). MABI scores were classified into five condition ratings of stream biotic integrity: very poor (6 to 10), poor (11 to 15), fair (16 to 20), good (21 to 25), and excellent (26 to 30). The study demonstrated that the resulting pilot index may provide useful information that will benefit policymakers and resource managers in formulating more comprehensive stream management approaches and conservation plans for priority sites in the region. [ABSTRACT FROM AUTHOR]

We conducted a preliminary analysis on the effects of various physical and chemical parameters on the morphometry and reproductive capacity of the calanoid copepod Filipinodiaptomus insulanus (Wright, 1928), endemic to the Philippines, by proxying clutch size (CS). Specimens and water quality readings were obtained between October 2019 and February 2020 from four sites in northern Philippines. Only the sizes of adult males and non-ovigerous adult females showed significant differences (P < 0.05) among populations. Non-eutrophic, temporary shallow waters were the predominant habitat type of F. insulanus , corroborating earlier observations that it is mainly found in relatively pristine environments. Correlation analysis showed a significant indirect relationship (P < 0.001) between the size of individuals and temperature, a potential adaptive response to its environment. Such observations may be valuable in preventing the disappearance of this species from parts of its previously known range. [ABSTRACT FROM AUTHOR]

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Sponge-microbe symbiosis is considered among the most primitive ecological relationships between metazoans and microorganisms. There is strong interest in understanding the occurrence of microbial communities in sponges due to their integral roles in host ecology, nutrient cycling, and production of potential bioactive secondary metabolites. However, most studies on sponges have been centered on marine species. In this study, the freshwater sponge Spongilla alba and its associated microorganisms were explored for the first time. Sponge samples collected from Lake Taal were taxonomically identified using gross morphology and spicules analysis. Both bacterial and fungal isolates were culturally characterized and molecularly identified using 16S rRNA gene for bacteria and ITS for fungi. Five bacterial species were identified as Pseudomonas sp., Enterococcus sp., Stenotrophomonas sp., Stenotrophomonas maltophilia, and Pseudomonas mosselii plus eight fungal species with spore sizes from 5-10 μm were identified as Colletotrichum truncatum, Trichosporon asahii, Rhizopus microsporus, Puccinia striiformis f. sp. tritici strain, Talaromyces columbinus, Phoma sp., Phomopsis sp., and Lichtheimia ramosa. Phylogenetic analysis revealed microbial sequences belonging to Proteobacteria (n = 4), Firmicutes (n = 1), Ascomycota (n = 4), Zygomycota (n = 2), and Basidiomycota (n = 2). The study reports infrequent occurrences of Enterococcus, Stenotrophomonas, Puccinia, and Lichtheimia species as freshwater sponge-associated microbes. This also presents the culturable microbial composition of freshwater sponges and rare occurrence of marine- and terrestrial-associated fungi T. asahii, R. microsporus, Phoma sp., Phomopsis sp., C. truncatum, and T. columbinus in a unique freshwater ecosystem such as Lake Taal. [ABSTRACT FROM AUTHOR]

The presence of the invasive calanoid copepod Arctodiaptomus dorsalis in Philippine inland waters has been reported in numerous studies. Attempts to understand how it effectively proliferated in the country's freshwaters have shown its preference towards shallow and productive waters - a feature shared by most lakes in the Philippines. In this study, we compared the body size and reproductive capacity - proxied by clutch size (CS) - of ovigerous female A. dorsalis obtained from established populations in the seven maar lakes (SML) of San Pablo, Laguna, Philippines. These measurements were also correlated with selected water quality parameters. Collection of ovigerous A. dorsalis and water quality parameters were conducted on a 3-mo sampling period during the southwest monsoon season in 2016. Statistical analysis shows that there exists a significant difference between the prosome length (PL) and CS of A. dorsalis from the seven lakes (p < 0.001), with the shallowest and most productive lake containing the most fecund population. Additionally, all water quality parameters showed a positive correlation with the PL and CS of ovigerous A. dorsalis from the SML (p < 0.01). This shows that the SML provides favorable conditions for the propagation of A. dorsalis, making it a model for in situ investigation of this invasive species' ecology; the first step in incorporating zooplankton ecology as a tool for the development of lake management systems. [ABSTRACT FROM AUTHOR]

Relatively limited information exists on Lake Wood's limnology and ecology, an ancestral lake of the Subanens. Here, we provide a limnological characterization of the lake -- exploring its physical, chemical, and biological features. The data on lake morphometry were gathered using an echosounder; lower depth water samples were collected using a Niskin water sampler for physicochemical analyses while surface water samples were collected at five sampling sites for phosphate (PO4) analysis; and zooplankton samples were collected at several depths through vertical towing in March-April 2019. Lake Wood, located at 320 m above sea level, has an extensive surface area covering 7.38 km² with a maximum depth of 85 m. Lake water comes from rainfall, small rivers, and groundwater and empties into the Dumanquilas Bay via its only outlet -- the Biswangan River. Land use of the lake is predominantly cultivated land. Moreover, based on the trophic state index (TSI), the lake's current trophic status is eutrophic. During the study periods, thermocline and oxycline formed at 15 m below the surface of the lake. We recorded three cladocerans (Ceriodaphnia cornuta, Diaphanosoma cf. sarsi, and Moina micrura) and one copepod species (Thermocyclops crassus) in the lake, all of which are common limnetic species found in the Philippines. Based on our findings, we recommend more efforts to manage and rehabilitate the lake to control and manage eutrophication's negative impacts. Finally, our study contributes to understanding lakes in Mindanao that are less represented in Philippine freshwater research. [ABSTRACT FROM AUTHOR]

Waste disposal is an important issue that needs to be addressed, not only for health and environmental reasons but also for its social and economic impacts. Three important waste streams that contribute to the growing amount of wastes generated come from medical, industrial, and electronic residual wastes. These residual wastes are usually just being dumped or disposed of in sanitary landfills. Apart from finding solutions to these environmental waste problems, these wastes can be a possible source of energy that can support our energy sustainability. In this study, three different waste streams, medical, industrial, and electronic wastes in Metro Manila – the capital region in the Philippines – were profiled and investigated for their potential as waste-to-energy (WTE) feeds. The daily generation, types of wastes, and heating values were studied. The total generated daily waste for medical wastes, hazardous industrial wastes, and residual electronic wastes that have a potential for WTE was about 143,834 kg/d or about 52,500 tons/yr. Its total energy potential was about 4,727 GJ/d. These large amounts of residual WTE feeds can potentially support daily energy needs, as well as mitigate problems associated with the typical disposal of these hazardous and residual wastes. [ABSTRACT FROM AUTHOR]

To understand methane (CH4) dynamics in tropical lakes and describe their importance in overall CH4 emissions, we observed temporal trends of CH4 stored in the water columns of Philippine lakes of different depths (shallow, moderately deep, and deep). We detected higher CH4 stored in profundal anoxic layers of deeper lakes. The average surface and profundal CH4 concentrations throughout our monthly monitoring were 0.27 ± 0.07 and 421 ± 189 μmol L–1 in the shallow lake, 0.48 ± 0.37 and 1,121 ± 125 μmol L–1 in the moderately deep lake, and 0.34 ± 0.23 and 943 ± 119 μmol L–1 in the deep lake. The fate of CH4 stored in the water column was related to depth, owing to different stratification and mixing regimes. Analyses of temporal relationships of CH4 with daily weather and physicochemical parameters revealed their impact on CH4 dynamics by controlling the frequency and mixing intensity throughout the year. Only shallow lake exhibited increase in CH4 concentrations with lowering atmospheric pressure. This allows vertical mixing and transport of CH4 from deeper to shallower layers. In moderately deep, and deep lakes, effects of daily weather parameters were not apparent on CH4 concentrations in the deepest layers (below 30 m depth). This suggests that lake depth and stratification should be considered for precise estimation of tropical lakes' CH4 emissions. Comparison with lakes under different climate conditions revealed the importance of tropical lakes for surface CH4 emission due to higher surface CH4 concentrations. Changes in water temperature is one of the factors controlling profundal CH4 production, storage, and its transport to shallower layer. Key Points: Vertical CH4 storage distribution in studied lakes are linked to episodic events, such as monsoons and extreme weather, driving turnoverWeather variables such as air temperature and atmospheric pressure are external drivers of stored methane in tropical lakesTropical lakes, with higher profundal water temperature, show more potential for storing and emitting CH4 than lakes from other regions [ABSTRACT FROM AUTHOR]

A massive invasion of the Neotropical calanoid copepod Arctodiaptomus dorsalis (Marsh, 1907) has been taking place in the Philippines since at least 1993. This copepod's fecundity is known to depend on food concentration, increasing temperature appears to have detrimental effects on its hatching success and survivorship, but parameters that are truly predictive of the successful integration and propagation of this species in particular bodies of water have not yet been identified. We conducted a spatial analysis of morphometric features and reproductive capacity, the latter proxied by clutch size (CS), of different populations of A. dorsalis inhabiting 11 tropical lakes in the Philippines. Correlations between either morphometry or CS and selected water quality parameters were investigated based on collections and measurements made from December 2018 to April 2019. Means of morphometric measurements differed significantly (P < 0.001) among the populations of A. dorsalis in all lakes. Total length (TL) of adult males, TL of non-ovigerous adult females, and CS of ovigerous females all showed significant (P < 0.001) inverse correlations with lake depth, accounting for about 30% of the observed variability among lakes (r = –0.55, –0.55, and –0.58, respectively). Shallow lakes, which are more homogenous in terms of nutrient distribution throughout the water column, thus provide a more suitable habitat than deep lakes for A. dorsalis and provides a partial explanation of the widespread occurrence and abundance of the species in the shallower, more eutrophic lakes in the Philippines. [ABSTRACT FROM AUTHOR]

In developing countries such as the Philippines, the inadequacy of even the most basic limnological datasets available has hindered planning and implementation of science-based management policies for inland waters. This situation is aggravated by overutilization of natural resources for ecosystem services such as water usage, aquaculture, fishing, and tourism. We reviewed published researches related to the Seven Maar Lakes (SMLs) in Luzon Is., Philippines to summarize information invaluable for the protection and sustainable use of these resources. Popular scientific search engines were utilized to gather peer-reviewed research articles and reports from both private institutions and government agencies. Literature and timeline from the 1930s to 2019 was classified into topics – namely socioeconomics, fisheries, biodiversity, and environment. Based on the literature survey, a variety of challenges, knowledge gaps, and promising research directions were identified, which are essential to the sustainable ecosystem management of the SMLs. Aquaculture practices impacting the lakes and its underestimated biodiversity were described. Measured vertical profiles of dissolved oxygen (DO), temperature, conductivity, pH, and salinity was supplemented by our preliminary limnological survey in the SMLs. Past and present monitoring data of selected physicochemical parameters were assessed from which the changing limnological status of the lakes was determined. We recommended measures motivated by strategic environmental assessments while still considering maintained economic yields. A sustained collaborative effort from different sectors is strongly suggested not only to manage the SMLs but also to address trade-offs among critical ecosystem services. Aside from the need for well-designed, long-term water quality monitoring, we also stress the synergistic interpretation of all available knowledge, which can contribute to the resolution of environmental issues at both local and global scales. [ABSTRACT FROM AUTHOR]

The genus Pseudodiaptomus is represented by 19 species in Philippine coastal waters. Of all these species found in the Philippines, P. brehmi Kiefer, 1938 is the only known truly freshwater pseudodiaptomid endemic to this country, which was originally described from Lake Naujan, Mindoro Island. After numerous attempts to find it in its type locality, we concluded that the former is no longer extant in this lake and has now been displaced by the invasive Neotropical calanoid Arctodiaptomus dorsalis (Marsh, 1907). Sampling in Lake Taal, on the nearby island of Luzon, resulted in the surprise discovery of P. brehmi populations coexisting with A. dorsalis. This rediscovery of P. brehmi in Lake Taal and its absence from its type locality, necessitate this report as well as the species’ morphological redescription. [ABSTRACT FROM AUTHOR]

Zooplankton are key ecosystem components in the pelagic food web. These organisms move vertically to avoid visual predators (i.e. fish) that prey on them; such movement is known as diel vertical migration (DVM). This study aims to elucidate the dynamics of the daily vertical migration of zooplankton and to determine the factors that govern their migration behavior in an understudied Philippine Lake in Lake Wood (Mindanao Island) from March to April 2019. Zooplankton and several environmental parameters were sampled in the deepest part of the lake at specific depths (1 m, 15 m, 30 m, 50 m, and 70 m) during noon and midnight. Adult females of Thermocyclops crassus displayed typical diel vertical migration patterns accompanied by large migration amplitudes. The food-rich epilimnion supports the abundance of T. crassus during the night and rather dwells in the hypolimnion during the day to evade visual predators. The study underscores the intricate interplay among predation pressure, temperature, water transparency, and total dissolved solids, collectively shaping the observed vertical migration behavior of adult female T. crassus. These perspectives provide a deeper understanding of how these organisms navigate the intricate challenges posed by their environment, offering insights into their strategies for survival and thriving within the ecosystem. [ABSTRACT FROM AUTHOR]

Arctodiaptomus dorsalis is an invasive calanoid copepod from America, and is now found in 23 out of 32 lakes and rivers in the Philippines. Live specimens of A. dorsalis were collected from Lake Taal and cultured in the laboratory. The specimens were reared under three different temperatures (25°C, 30°C, and 35°C) with the same food and light conditions, i.e. ~105 cells mL-1 of Chlamydomonas reinhardtii and 12L:12D at ~60 lx, respectively. Post-embryonic development times from hatching to adult decreased from 31.5 d to 18.3 d as the temperature increased, while those during naupliar stages were quite similar, i.e. 4.4, 2.8 and 2.3 d at 25, 30 and 35°C, respectively. The naupliar durations were substantially shorter than the copepodid stages. Clutch sizes were almost the same, 8.7-9.2 eggs clutch-1, among all temperatures tested, while hatching success decreased from 85.9% at 25°C to 24.2% at 35°C. Overall survival rates from hatching to adult decreased as well from 67% at 25°C to 23% at 35°C. This is the first successful attempt to culture A. dorsalis collected from a freshwater lake in the Philippines. [ABSTRACT FROM AUTHOR]

In this paper, we aimed to contribute to the conservation research of a heavily impacted tropical lake ecosystem by characterizing its previously undescribed fish diversity and also elucidating the trophic structure of its fish community. Our study area is Lake Sampaloc, a small crater lake in the southern region of Luzon Island, Philippines. This lake has been heavily used for economic resource functions, such as aquaculture, for decades. Hindrances to the effective implementation of regulatory provisions have produced detrimental ecological effects on the lake, which has recently been declared as "Threatened Lake of the Year 2014". We employed several sporadic fish surveys during a span of two years (2012 to 2014) to identify fishes in the lake. We also used stable isotope analysis to elucidate the trophic level and production reliance of important aquatic consumers. We discovered that the lake fish populations are heavily reliant on periphyton production and are mostly composed of non-native and potentially established invasive fish species. In addition, trophic niche overlaps are observed among non-native fish and native species. For the past three decades, Lake Sampaloc has been classified as eutrophic with high phytoplankton standing biomass. A possible direction for lake rehabilitation research is to investigate ways to change the present turbid state into a clear water system that is predominantly composed of submerged native vegetation. Such a macrophyte-based environment may help sustain the development and recruitment of native juvenile fish and also provide a more diverse functional habitat for fish assemblages that have overlapping trophic niches. [ABSTRACT FROM AUTHOR]

Macrophytes play an important role in the aquatic ecosystem since they are good bioindicators and serve as habitat for littoral fishes. This research involves the use of the hydroacoustic method aided by visual observation and quantification in determining the distribution and abundance of submerged macrophytes in the littoral zones of Lake Taal. The results were used to generate spatial distribution and percent cover maps of macrophytes in the lake. Based on the surveys, five macrophyte species were present in Lake Taal. Denser macrophyte beds were concentrated in the south basin of the lake. High nutrient levels in the south basin contributed to heavy macrophyte growth in this area, which usually come from run-offs from the residential, commercial and agricultural watersheds. The lesser biomass of macrophytes in the north basin was attributed to clearing activities due to the construction of fish cages for aquaculture. Furthermore, we were able to observe that there were different dominant species in the north and south basins of the lake; Najas indica was more prominent in the north basin, while Vallisneria nanawas more common in the south. This study shows that anthropogenic sources of excess nutrients and other activities such as aquaculture play a role in altering the distribution of macrophytes in Lake Taal and how these can have potential detrimental impacts to the littoral zones of the lake. [ABSTRACT FROM AUTHOR]

Zooplankton were collected from Lake Taal between January and December 2008 in order to test for differences in species composition and abundance between a lake basin with intensive fish cage (FC) aquaculture and an open water area without FCs. Most species showed similar patterns of occurrence in both basins while having differences in abundance. Several rotifer species were more abundant in FC sites most of the year, while for microcrustaceans higher abundances in FC sites only happened during the first 2 months. Their distribution is attributed to the presence of higher nutrient levels in FC sites as well as wind-induced basin-wide water movements during the different monsoon seasons which disperse plankton and nutrients from FC sites to other parts of the lake. Zooplanktonic indicators, such as the Brachionus- Trichocerca quotient ( Q) and the ratio of calanoids to cladocerans and cyclopoids, clearly demonstrate the eutrophic state of the lake. A comparison with previous studies suggests that the lake was already eutrophic prior to the introduction of aquaculture in the 1970s. The trophic conditions in Lake Taal may be attributed to the lakes' tropical and volcanic nature, with productivity further enhanced by increased nutrient input from aquaculture. [ABSTRACT FROM AUTHOR]

Limnetic zooplankton serve as a major food source for pelagic fi sh. This paper updates the species composition, diversity and community dynamics of limnetic zooplankton in the two basins of Lake Taal, an active caldera lake ecosystem. Samples obtained from January to December 2008 included 15 rotifer, six cladoceran and three copepod species. Eight species are new records for the lake. The zooplankton community is dominated by copepods, which contributed 64% to total abundance and 84% to total biomass. Diversity values for rotifers and cladocerans were low and similar in both lake basins. The composition, diversity and homogenous spatial distribution of zooplankton in Lake Taal is typical for tropical lakes with a high trophic state which may be a response to the prevailing conditions infl uenced by its location, geological origin and meteorological factors. [ABSTRACT FROM AUTHOR]

The article discusses findings of a study on the composition and quantity of zooplankton found in freshwater sardine that were caught in Taal Lake, Philippines. The research revealed that 90 percent of the stomach contents of freshwater sardine consisted of large adult copepods and 10 percent cladocerans and rotifers. An analysis of collected samples from July 2003 to July 2004 to determine the zooplankton diet of Sardinella tawilis determined that freshwater sardine prefers to consume larger prey since they are more visible. Researchers noted that smaller-bodied organisms dominated the zooplankton community because of size-selective predation.

Lotic ecosystems in urban areas are severely impacted by anthropogenic environmental stressors, such as deforestation and nutrient pollution, due to socioeconomic activities in the catchment. To work out measures for identification and mitigation of concurrent multiple stressors to a stream system, it is necessary to assess the relative importance of impacts by the individual stressors. Here we aimed to discriminate the covarying effects of nutrient pollution and deforestation on benthic macroinvertebrate communities in an urbanised tropical stream system. In the Silang-Santa Rosa Subwatershed (SSRS) of Laguna de Bay, benthic macroinvertebrates and physicochemical environments were investigated at 13 sites varying in human population density, riparian canopy, and land-use pattern as indicated by geographic information systems in the catchment. Regression and multivariate analyses were performed to identify the drivers of the biodiversity loss and understand its underlying mechanisms. In the SSRS, where rapid economic growth took place without updating poorly installed wastewater treatment plants (WWTPs), domestic activity indicated by human population density in the catchment was the primary factor in generating heavy phosphorous loadings (mean total phosphorus = 0.91; range = 0–1.50 mg/l) that caused hypoxia (mean dissolved oxygen = 2.98; range = 0.13–6.27 mg/l) in stream waters and subsequently reduced macroinvertebrate diversity (mean H' = 0.91; SD ± 0.61). Nutrient and organic pollution and riparian deforestation explained 53.5% and 9.7% of the variation of benthic macroinvertebrate communities in SSRS, respectively. Given such scenario, additional WWTPs servicing urban developments and improved riparian canopy cover in the SSRS can be both strategic and cost-effective in the initial steps of environmental mitigation in urbanised streams, especially in rapidly developing countries. [ABSTRACT FROM AUTHOR]

• Individual-based model to study the production of an invasive copepod. • Model integrates the effect of food concentration on several individual endpoints. • Calibration of the model benefits from measures obtained in vivo. • Quantify the combined impact of food and predation on egg and offspring production. Arctodiaptomus dorsalis is an invasive calanoid copepod originally from America and has recently established a population in Lake Taal in the Philippines. It has been proposed that eutrophication due to aquaculture contributes to the establishment and success of this species. This study aimed to clarify this hypothesis by quantifying the effect of increasing food concentration on the reproduction of A. dorsalis using an Individual-Based Model. We parameterized food concentration-dependent equations to simulate the effect of different food concentration on the reproductive traits (latency time, embryonic development time, clutch size, and hatching success) of this species using data from the literature and simulated the reproduction of 1000 independent females for 20 days at different food concentration, taking into account the variability among individuals. The simulation results showed that the cumulative production of eggs and offspring increased continuously with time when the food concentration was above 3.2 × 104 cells mL−1, suggesting that this value was the threshold concentration required for stable reproduction of A. dorsalis. This value is not particularly low compared to other copepods. Hence, our result revealed that the food use efficiency of A. dorsalis is not particularly outstanding and urge the need of a comparison with native species to confirm a possible superiority. We suggest that A. dorsalis has filled the ecological niche left vacant by the disappearance of the original species due to the deterioration of water quality caused by the eutrophication of the lake. The reproductive cycle model developed in this study constitutes a necessary step in the development of a complete population dynamics model, which can help clarify the invasive abilities of A. dorsalis. [Display omitted] [ABSTRACT FROM AUTHOR]

Unsustainable urbanization in the Indo-Pacific continues to threaten terrestrial and aquatic ecosystems due to habitat disturbances driven by human pressures. The Marikina Watershed, one of the most critical watersheds in the Philippines, has been exposed to economic and population growth resulting in landscape modification and water quality degradation. This led to establishment of the Upper Marikina River Basin Protected Landscape (UMRBPL) to rehabilitate the watershed ecosystem. To strengthen this conservation initiative, we aimed to assess whether the establishment of UMRBPL has been effective in conservation of benthic macroinvertebrate diversity in streams of the Marikina Watershed. Sixteen streams, eight from UMRBPL and eight from adjoining unprotected areas, were monitored for benthic macroinvertebrate assemblages and their habitat environments, such as pH, water temperature, dissolved oxygen, total dissolved solids, conductivity, salinity, and canopy openness. Principal component analysis and non-metric multidimensional scaling based on the environmental variables and biological metrics, respectively, revealed that habitat quality and benthic macroinvertebrate assemblages significantly differed between the protected and unprotected streams, with the former having better environment and higher biodiversity. More precisely, protected streams have significantly higher dissolved oxygen and lower canopy openness and material loadings as compared to unprotected streams. Consequently, taxon richness was four-fold higher in protected streams while stream quality indices based on abundance of key invertebrate groups (EPT and EPTC) were ten-fold higher in protected streams, as compared to unprotected streams. This study demonstrates that freshwater protected areas play crucial roles in the conservation of stream ecosystems and biodiversity under rapid urbanization in developing countries, like the Philippines. [ABSTRACT FROM AUTHOR]