Preferred Species Research Articles

The challenges associated with firewood supply and analysis of fuel quality parameters of the tree species used as firewood in Rwanda

Firewood serves as an essential cooking energy source for households in Rwanda. However, the supply of firewood is hindered by various challenges, such as escalating scarcity, long distances traveled to collect firewood, and reliance on low-quality biomass during shortages. This study aimed to assess the challenges associated with firewood supply and analyze the fuel quality of tree species used as firewood in Rwanda, using systematic sampling with 504 and 368 farmers, respectively, in Bugesera and Musanze Districts. The results indicated that women and children are predominantly involved in firewood collection, with households traveling over 9 kilometers for firewood collection and spending 5 to 8 hours per collection session. Additionally, 42% and 43% of households in Bugesera and Musanze Districts gather firewood twice weekly. The most preferred species for firewood were Eucalypts spp, Senna spectabilis, Grevillea robusta, and Alunus acuminata due to their rapid drying, low smoke production, and efficient fuel qualities. The fuel quality analysis indicated that Eucalyptus spp., Grevillea robusta, Croton megalocarpus, Alnus acuminata, and Senna spectabilis exhibit a substantial promising bioenergy characteristic that points to their potential for sustainable energy production. The study advocates for strategically incorporating high fuel qualities, rapid growth, and regeneration of tree species into trees-based systems in the agricultural landscape to ensure a sustainable firewood supply while mitigating forest degradation.

Women's preferences for associated species in cocoa-based agroforestry systems and their uses in the Kokumbo Sub-Prefecture (Côte d'Ivoire)

Due to their multiple uses, species associated with cocoa trees have an important socio-economic and environmental value for women in Central Côte d'Ivoire. Based on surveys followed by an inventory carried out in six villages of the Sous-Préfecture of Kokumbo, this study assesses women's preference for cocoa companion species using the pebble distribution method, in order to quantify the value accorded by the latter according to their various uses. A total of 79 plant species were identified, divided into 67 genera and 31 families. These species associated with cocoa trees have an explicit value for women, as they meet the vital needs of farming households, such as self-consumption (43.32%), sale (35.21%), shade (7.53%), timber and firewood (7.15%). Using the pebble distribution method, we have highlighted the most important species associated with cocoa trees for women. For self-consumption, we have Dioscorea spp with 29.47% and Musa paradisiaca (18%). They attribute a high commercial value to Musa paradisiaca (25%) and Persea americana (21%). They also prefer species that provide good shade for cocoa trees, such as Ceiba pentandra (19.74%) and Milicia excelsa (11.30%). Those that provide good firewood and energy, such as Milicia excelsa (28%) and Albizia zygia (19%). Domestication of the tree and shrub species most appreciated by farmers could stimulate their regeneration. The marketing of products from cocoa agroforests could enable women to acquire financial autonomy in order to improve the living conditions of their households in general and those of their children in particular.

Reaction of Wood Ants to a Large-Scale European Spruce Bark Beetle Outbreak in Temperate Forests

In the Białowieża Forest, Norway spruce is the preferred host tree species for wood ants, both in coniferous and mixed stands; thus, spruce mortality as a consequence of a continuous spruce bark beetle outbreak in the Białowieża Forest since 2012 could have severe consequences for wood ant colonies, as well as their vitality and distribution. The main aim of this study was to assess whether the bark beetle outbreak had any effects on wood ant nest density and abundance and whether we could find any factors affecting the dead spruce distribution around ant nests. A re-inventory of active and abandoned wood ant nests in our study area was conducted from April to July 2022, using the same procedure as the previous inventory performed in 2016. The wood ant nest density was 0.11 per ha and remained practically the same relative to that determined in 2016. Our results indicate that, despite the importance of spruce for wood ants, in situations when only part of the spruce trees die, natural forest disturbances such as bark beetle outbreaks can actually have positive effects because more light can reach the forest floor, thereby promoting the establishment of new nests.

Public preferences for edible invasive alien marine species - The Atlantic blue crab in southern Italy

Since 2014, the provision of the aquatic ecosystem services has been gradually affected due to the biological invasion of Callinectes sapidus (Rathbun, 1896, Crustacea, Decapoda, Portunidae), commonly known as Atlantic blue crab, across several lagoon-like locations in Italy. In addition, this serious aquatic invasive species, native of North American coasts, has already inflicted economic damage of about EUR 100 million to the Italian fishing and farming communities over the past year. To counter their severe and rapid spread, the Italian Government has encouraged the fishing communities to catch as many as possible and commercially exploit them for human consumption in an attempt to manage their expansion. Since there is an ongoing promotion for the consumption of blue crab by forging novel food businesses in Italy, this paper aims to predict the public preferences and their willingness to pay (WTP) towards this biological invader. For this purpose, a discrete choice experiment approach is used, by means of a multinomial logit model (MNL) and latent class model (LCM). The social field survey involves a representative sample of 440 valid respondents in Apulia Region, southern Italy. The descriptive statistics results reveal that 67.50% of the local citizens interviewed know about the blue crab invasion, while 29.09% of them have already consumed this seafood species. In addition, the MNL results show that the most appreciated attributes of the blue crabs by respondents are freshness and large size. Further, the LCM findings reveal two representative classes of Apulian consumers; the first group of citizens (70.9% of total respondents) expresses positive appreciation for consuming blue crabs, while the second group (29.1% of total respondents) is not willing to pay a premium price regarding this potential commercial activity. Furthermore, the econometric results show that the average value that Apulian’s (i.e. those belonging to Class/Group I of respondents) WTP for blue crabs’ consumption is about EUR 18 per kilogram. In this regard, this research has public and private implications and may reasonably promote the commercial exploitation of blue crabs, enhancing the reduction of its population density through human consumption as a promised management control strategy and forging a novel profitable business mainly for local small-scale artisanal fisheries.

Impacts of Carbon Sequestration Projects on Household Income, and Consumption Expenditure of Smallholder Farmers in Meru County, Kenya

Mitigation of climate change has led to the initiation of carbon sequestration projects in the developing countries in compliance with the Kyoto protocol of 1997. The protocol goal was for industrialized countries to reduce their greenhouse emission by funding carbon projects in developing countries. The study focused on voluntary carbon projects involving smallholder farmer practicing agroforestry. The impacts of these projects on farmers’ household income and consumption expenditure were evaluated. A survey and quasi-experimental research design targeting 207 smallholder farmers was conducted in three wards within Igembe South Sub- County namely Athiru Gaiti, Akachiu and Kiegoi/Antubochiu. Data was collected from secondary sources and primary sources. The data was analyzed using propensity matching techniques. The results showed participation in the carbon sequestration program has a significant impact on the income (t= -3.8081 w/df 205, p=0.0002) at a significant level 0.05. Consumption expenditure of the participant was also significant (t= -4.7034 w/df 205, p= 0.0000). Exotic tree species were more preferred to indigenous trees species. Grevillea robusta (A. Cunn. Ex R. Br) although naturalized, was the most preferred exotic tree species (33.9%) while (17%) of the respondents planted Cussonia holstii (Harms ex Engl.) - an indigenous tree species. Income status of majority (86%, f=77/90) farmers participating in the carbon program increased. Expenditure status of majority (68%, f=61/90) of participating farmers in the project also increased. Savings, inflation, alternative uses led to decrease in consumption expenditure. The study recommends the carbon sequestration project be expanded in more areas, conduction of awareness campaigns to reach more farmers, increase of the carbon credit amount paid to the farmer, the project proponent and partners to continue assisting farmers with tree seedlings for free. The study also recommends use of multipurpose exotic tree species since they have a fast growth rate

Assessment of Fuel Wood Consumption and Its Effect on Forest Depletion in Dry Deciduous Forest of Haliyal Taluk, Uttar Kannada District, India

Forest plays a significant role in extending wood and non-wood resources around the world, Forests provide ecosystem services, such as timber, food, fuel, fodder, non-wood products and shelter, which are essential for human well-being. However the increasing demand and pressure on forest resources majorly like fuel wood lead to degradation of forests. Hence it is important to assess the fuel wood consumption pattern and its impact on the forest for sustainable management of resources. In the present study, Haliyal taluk was selected, the area which is under rapid urbanization, surrounded by dry deciduous forest and the people living in that area depend on forest for fuel wood consumption. The study examined fuel wood collection among different farmer categories: large, medium, small, and landless. Results from the semi structured questioner survey revealed that medium farmers collected the most fuel wood. The total fuel wood consumption in Haliyal taluk was 5232.2 tonnes, with an average household consumption of 2.60 quintals of fuel wood per year. Major preferred tree species for fuel wood were Xylia xylocarpa, Terminalia tomentosa and Lagerstroemia lanceolata, which are valued for their high energy content, favourable burning characteristics and availability. For estimation of forest degradation Randomized Block Design was used and the study classified the forest vegetation into four crown density classes: Very Dense Forest (T1), Moderately Dense Forest (T2), Open Forest (T3), and Scrub (T4). Data was collected from 20 plots (20 x 20 m each) across these classes to measure forest depletion. The results showed that statistically significant differences in degradation levels, with the highest depletion (31.56 m³/ha) in very dense forests followed by moderate depletion (6.75 m³/ha) in moderately dense forests and the lowest (2.4 m³/ha) in scrub forests. This pattern reflects greater anthropogenic pressures and higher fuel wood availability in more dense forest types.

Biological Properties Influenced by Different Tree Species in Deep Chambal Ravine of Madhya Pradesh, India

An experiment site planted with different multipurpose trees and their impact on soil biological properties were measured and analyzed. Based on overall growth on biological properties showed that preferred ranking tree species in the following order viz., maximum soil microbial biomass carbon, dehydrogenease acticity and soil respiration were recorded under Moring a oleifera, respectively followed by Albizia lebbeck, Azadirachta indica, Acacia nilotica, Dalbergia sissoo, Terminalia arjuna, Millettia pinnata and Gmelina arborea while Justicia adhatoda was recorded minimum, respectively. Tree stand growth significantly improved the soil biological properties. Thus, A. Moringa oleifera and Albizia lebbeck species are most suitable multipurpose hardy tree species for rehabilitation of medium and deep ravines of Chambal ravines in India.

Invertebrate-biased diet of burrowing owls in a newly-restored coastal grassland

Recovering biodiversity across trophic levels is a major challenge in restoration ecology. Specifically, predator population recovery depends on the timely re-establishment of their preferred prey species in restored habitats. Here, we evaluate potential dietary factors contributing to the loss of western burrowing owls (Athene cunicularia hypugaea (Bonaparte, 1825)) from a newly-restored coastal grassland. We examined owl pellets and found that burrowing owl diets were relatively low in vertebrate prey during their brief occupation of the restoration site (2.6% of prey items; found in 61.8% of sampled pellets). We suggest that preferred food limitation may have been one contributor to the loss of owls from the restoration site. These findings suggest the need to prioritise re-establishment of prey communities for effective long-term recovery of burrowing owls in restored landscapes.

Familiarity preferences in zebrafish (Danio rerio) depend on shoal proximity.

Individuals of many species prefer to associate with familiar conspecifics from their established social group over unfamiliar conspecifics. Such familiarity preferences are thought to be adaptive and have been documented widely in many social fishes. Zebrafish (Danio rerio) are extensively studied, highly social fish that form stable shoals in the wild, however there is only mixed evidence for familiarity preferences in this species. Here, we test how a small variation in experimental design can influence preferences for familiar conspecifics in D. rerio by varying the distance between two stimulus shoals of fish in a shoaling choice paradigm. Individual subjects tested for their preference to shoal with familiar or unfamiliar groups of conspecifics showed a preference for familiar fish when the two shoals were 30 cm apart, but not when they were 45 or 60 cm apart. Thus, choice tests can be used to detect familiarity preferences in D. rerio, but only when alternate shoals are close together, as increased intershoal distances seemingly prevent subjects from displaying their preference. Longer distances may inhibit preference behavior due to the higher risk of crossing between shoals, alternatively subjects may be unable to reliably discern distinguishing cues of familiarity when the shoals are further apart. Our results demonstrate that while familiarity preferences exist in D. rerio, experimental test design is critical for detecting and measuring these successfully.

Nutrient screening of Chlorella vulgaris and C. variabilis using high-throughput biolog phenotype arrays

Microalgae, particularly Chlorella species, are versatile microorganisms with significant scientific potential in various domains, including recombinant protein production, wastewater treatment, biofuel production, bio-fertilizers, food source, pharmaceuticals, and carbon capture. However, conventional growth media have often been the default choice for Chlorella cultivation. This study utilizes Biolog phenotype array plates to explore the growth responses of Chlorella vulgaris and Chlorella variabilis to a broad spectrum of carbon, nitrogen, phosphorus, and sulfur sources. The growth dynamics were captured by integrating the area under the OD-time curve. The results revealed growth preferences for both Chlorella species, emphasizing their unique nutrient source requirements and illuminated some unexpected growth behaviors. C. vulgaris exhibited equal preference for trehalose as glucose, and C. variabilis was unable to metabolize nitrate or sucrose, two staples of modified BBM media most commonly used for its cultivation. These findings contribute to a deeper understanding of the metabolic capacities of C. vulgaris and C. variabilis, informing potentially more efficient and tailored microalgal cultivation practices across diverse applications.

A shift in substrate requirement might cause speciation of the lichenized fungi, Varicellaria hemisphaerica and V. lactea (Pertusariales, Ascomycota)

Proper species recognition is required to correctly estimate species preferences and their vulnerability or for eco-evolutionary inference. Varicellaria hemisphaerica and Varicellaria lactea are almost completely morphologically homogeneous species with unclear identification features. To evaluate the importance of morphological, chemical, and ecological characteristics used in recognition of these species, we tested 670 specimens, of which 42 were analyzed phylogenetically using nucITS rDNA, SSU rDNA, and LSU rDNA markers. This integrated taxonomical approach showed that V. hemisphaerica is distinct from V. lactea, and that substrate requirements, together with phylogenetic differences and the size of soredia, differentiate these species. The chemical composition of secondary lichen metabolites in both analyzed species showed similar variation and, therefore, this feature is not diagnostic in species recognition, although suggested by previous studies. The potential speciation of the two species seems to be caused by the shift in the substrate requirements.

Landscape Homogeneity May Drive the Distribution of Koala Vehicle Collisions on a Major Highway in the Clarke-Connors Range in Central Queensland, Australia

After the loss and fragmentation of habitat, vehicle collisions are one of the main threats to the long-term survival of wild koalas. Koala road strike data were analysed for a section of the Peak Downs Highway between Nebo and Spencer’s Gap, west of Mackay, Queensland, Australia. The analysis was carried out on 345 records (October 2014 to November 2023), and results suggested the spatial distribution of koala road strike followed a random pattern along this section of the highway, assuming a Poisson point pattern on a linear network. An analysis of the candidate predictors of koala vehicle collisions, including habitat and road variables, found that the amount of high-quality koala habitat (as defined by the local koalas’ tree species preference) present and the driver visibility were the only significant predictors. The relative homogeneity of landuse and vegetation across this landscape may mean that koalas do not concentrate at specific crossing points. More research, including detailed habitat mapping, is needed into this population, which currently lacks government and conservation attention, to inform mitigation efforts and reduce mortality rates for this potentially nationally significant population.

Acetylxylan esterase is the key to the host specialization of wood-decay fungi predicted by random forest machine-learning algorithm

Wood-decay fungi produce extracellular enzymes that metabolize wood components such as cellulose, hemicellulose and lignin. Each fungus has a preference of wood species as the host, but identification of these preferences requires a huge amount of cultivation data. Here, we developed a method of predicting the wood species preference, Angiosperm specialist or Gymnosperm specialist or generalist, of wood-decay fungi using the random forest machine-learning algorithm, trained on the numbers of families associated with host specialization in the Carbohydrate-Active enZymes database. The accuracy of the prediction was about 80%, which is lower than that of the classification of white- and brown-rot fungi (more than 98%) by the same method, but the reason for this may be the ambiguity of the definition of “preference” and “generalists”. Carbohydrate esterase (CE) family 1 acetylxylan esterase was the most significant contributor to the prediction of host specialization, followed by family 1 carbohydrate-binding module and CE family 15, mainly containing glucuronoyl esterases. These results suggest that the ability to degrade glucuronoacetylxylan, a major hemicellulose of Angiosperm, is the key factor determining the host specialization of wood-decay fungi.

Length-based assessment of penaeid shrimp fishery stocks along the north-eastern Arabian Sea

Penaeid shrimps are a key resource in marine fisheries and are of great ecological and economic importance. The north-west (NW) coast of India contributes significantly (~30%) to the penaeid shrimp landings in India. Four species of penaeid shrimps, namelyParapenaeopsis stylifera, Solenocera crassicornis, Metapenaeus affinis, and M. monoceros, were assessed using Length-based spawning potential ratio (SPR) based on the length frequency data collected during 2017-21, from commercial trawlers operating in the depth range of 20-100 m along the north-west coast of India bordering the north-eastern Arabian Sea. The current status (2021) of P. stylifera, S. crassicornis and M. affinis was found to be healthy, with a spawning potential ratio of ≥ 0.40. For M. monoceros, the SPR was slightly below 0.40 (0.34-35), however, considering the fast growth and short generation time for the resources, the stock status can be considered fair. Significant reduction in fishing pressure (F/M < 1.0) and increase in SPR (>0.40) during COVID-19 affected years (2020-21) were evident. The reduction in fishing hours during the pandemic has allowed the resource to regain the target reference point (TRP) for SPR. Declining catches over the past decade for the group are not due to resource depletion but for the shift in species preference and the diversification of trawls in the region, with bottom trawling giving way to pelagic trawling. Keywords: Sustainability, Spawning potential ratio, COVID-19, Penaeid shrimps

The occurrence patterns and alternative host use of the generalist parasitoid Parvilucifera infectans (Alveolata, Perkinsozoa) of marine dinoflagellates revealed by a high-frequency time series microscopic data at a temperate coastal site

Species belonging to the genus Parvilucifera (Alveolata, Perkinsozoa) are known as generalist parasitoids that can infect a variety of marine dinoflagellates and ultimately kill the host cell. Despite the accumulation of knowledge on Parvilucifera parasitoids over the last twenty years, the occurrence pattern and use of alternative hosts for persistent transmission within fluctuating natural dinoflagellate host communities have received relatively little attention. To address this, high-frequency (i.e., daily) time series protist monitoring was conducted for 411 days, from April 2020 to May 2021, at a temperate coastal site in Jinhae Bay, Republic of Korea. This site was characterized by frequent blooms of mixed dinoflagellates throughout most of the year. Nonetheless, Parvilucifera infections were detected only in the spring seasons, and its occurrence pattern was primarily governed by the presence and cell density of its primary dinoflagellate host, Akashiwo sanguinea. As long as the primary host was present at high densities (greater than 104 cells L-1), this primary host alone could support the transmission and persistence of the parasitoid. However, if the cell density of the primary host started to decline, then Parvilucifera searched for and exploited alternative hosts for its continued survival. Taken together, this study suggests that the presence and cell density of its preferred primary host species and the duration for which the density remains above the threshold level are key factors that regulate the timing of Parvilucifera occurrence and alternative host use.

Geospatial fish consumption patterns and paradigmsin Odisha State, India

The current study investigated the geographic distribution and characteristics of fish consumption in Odisha State, India. The study was conducted across various locations, comprising urban coastal (Puri), rural coastal (Balasore), urban non-coastal (Cuttack) andrural non-coastal (Mayurbhanj) districts in the state. A total of 1440 respondents were selected for assessing the fish consumption patterns across theses diverse locations. According to the consumer profile, 82% of respondents were between the age of 20 and50, with 24% having a college degree. More than 90% of the respondents reported that they consume fish regularly. The results indicated that increased fish availability (62%), accessibility (52%), and affordability (48%) contributed to a rise in fish consumption over time. Over all, distance to the fish access points ranged between 1 to 2 . Catla was the most preferred fish species among consumers, followed by Rohu and other carps. Several barriers to increasing fish consumption were identified based on the perceptions of the respondents, such as erratic availability, lack of preference for fresh fish, wide price variations, limited access and high price. The data were analysed using a range of statistical and econometric methods, including conjoint analysis, preference assessment index and discriminant analysis. Keywords: Coastal, Conjoint analysis, Discriminant analysis, Fish consumption, Non-coastal, Preference assessment index

Tree species richness suppresses red imported fire ant invasion in a subtropical plantation forest

Abstract The ecological resistance to the invasion of alien species has been extensively researched at the within‐trophic level; however, the effect of cross‐trophic interactions remains largely unknown. The red imported fire ant (RIFA, Solenopsis invicta) is a globally invasive species, and a cross‐trophic interaction study between RIFAs and plants may provide a more comprehensive understanding and management of its invasion. We hypothesized that the diversity of trees, which are the primary producers supporting terrestrial ecosystems, could suppress the invasion of omnivorous RIFAs by regulating food resources (e.g. plants and arthropods) and the microenvironment (e.g. soil microclimate) as well as enhancing competition with other carnivorous ants. To test this hypothesis, we investigated RIFA abundance and mound numbers across tree species richness gradients in a subtropical plantation forest. Using structural equation models, we discovered that tree species richness had contrasting effects on RIFA abundance and mound numbers. RIFA abundance directly decreased with higher tree species richness because of the dilution effect (i.e. lower abundance of preferred tree species). In contrast, RIFA mound numbers indirectly increased with tree species richness via an increase in arthropod abundance (excluding ants) (i.e. more ample food resources for RIFA). Moreover, warmer soil temperatures decreased RIFA abundance, whereas other carnivorous ant species richness and abundance negatively affected RIFA abundance and mound numbers. Synthesis and applications: Our findings demonstrate that the ecological resistance to RIFA invasion is influenced by tree species richness in a complex manner; specifically, the relative strengths of the effects of tree species characteristics, native competitors and environmental conditions are likely to impact the power of ecological resistance. This highlights the importance of cross‐trophic interactions underlying the resistance of complex ecosystems to alien species invasion; therefore, maintaining diverse tree communities in controlled systems (e.g. suburban and urban green spaces) should be viewed as a potential strategy for controlling RIFA invasion.

Adoption of agroforestry systems by smallholders’ farmers in the Sudano-Sahelian zones of Mali and Burkina Faso, West Africa

AbstractDespite the well-known potential of agroforestry systems to sustain livelihoods and ecosystem services, their targeted adoption in the Sudano-Sahelian zone of West Africa is low. To address this, we used questionnaires with 279 farmers to understand their socio-economic characteristics determining the adoption of agroforestry technologies and to record the preferred tree species in the Koulikoro region of Mali and West-Central region of Burkina Faso. The result of a binary logistic regression showed that income, off farm activities, average number of owned sheep, cooperative membership, forage security, and maintained trees and shrubs fostered the adoption of agroforestry technologies. Contrarily, the adoption of agroforestry technologies was negatively influenced by household size and crop yield. Our data show that agroforestry parklands are the most popular agroforestry technology. The most common agroforestry tree species in the study region was Vitellaria paradoxa C. F. Gaertn. The dominance of V. paradoxa within these parklands may be partly explained by the tree’s adaptation to severe drought and fire hazards, which are common to the study region. The study also revealed that smallholder farmers in Mali maintained trees on farms mainly for food security, whereas in Burkina Faso trees were mainly kept for maintaining soil fertility. We conclude that in all initiatives aimed at promoting the adoption of agroforestry in the study region, efforts should be made to consider farmers’ socioeconomic characteristics, tree preferences, and perceptions (as identified in this study).

Circadian migrations of cave-dwelling crustaceans guided by their home chemical seascape

Organisms release and detect molecules for defense, reproduction, feeding strategies and finding suitable habitats. For some migratory species, homing behavior could be related to the recognition of their home chemical fingerprint made of an assemblage of molecules from their habitat. In the marine realm, the functioning of ecosystems such as underwater caves largely depends on trophic interactions between the caves and the outside environment. A key feature of these interactions relies on the circadian migration of small crustaceans (Mysida) from the cave habitat to the open sea. Recently, it has been hypothesized that these migrations could involve chemical mediation. Behavioral experiments using a two-choice system have shown that cave mysids significantly detect cave seawater rather than a control water from the open sea. Here, we used the same experimental system to investigate habitat recognition by two populations of the cave mysid Hemimysis margalefi. Both populations were submitted to a choice between three distinct cave seawaters vs. a control seawater. Additionally, experiments tested the water preference of a non-cave mysid species (Leptomysis sp.) between control and cave seawaters. To evaluate whether the choice of mysids was influenced by chemical cues from conspecifics, a complementary experiment on H. margalefi was conducted. Results demonstrated that each studied mysids population significantly recognizes the water of its own home habitat, and that this behavior is not influenced by the occurrence of H. margalefi’s exudates. Mass spectrometry-based metabolomic analyses revealed that each cave seawater had a specific chemical fingerprint with only a few reproducibly detected signals belonging to different chemical classes: peptides, alkaloids, fatty acids, steroids but also inorganic molecules. Organic pollutants have also been reproducibly detected. Among the detected compounds, one oxylipin derivative and one peptide could be considered as chemical markers of the cave ecosystem. Therefore, we postulate that the chemical seascape of each cave participates to mysid circadian migrations which are analogous to a daily-based homing behavior.

Reef fish biodiversity and occurrence of endangered sharks within a small marine protected area off Sint Maarten, Dutch Caribbean

AbstractMarine protected areas (MPAs) are common conservation tools supporting the protection of threatened marine fishes, such as sharks. However, the creation of shark MPAs has been less common in the Greater Caribbean region despite a growing need and opportunity. In this study, we evaluated the occurrence of shark and reef fish biodiversity off Sint Maarten, Dutch Caribbean, with a particular emphasis on endangered shark presence within the Man of War Shoal Marine Protected Area (MPA). We utilized baited remote underwater video systems (BRUVs) to gather non-invasive data on the abundance and diversity of reef fish and shark species inside and outside the local MPA. Generalized linear models (GLMs) revealed no significant effect of protection status on the presence of the endangered Caribbean reef shark (Carcharhinus perezi). However, we found a significant influence of depth on shark occurrence, as well as an effect of habitat type on shark and reef fish biodiversity, with reef habitats showing the greatest significance. These results suggest that the effect of small coastal MPAs on bolstering local endangered species conservation in the Dutch Caribbean is likely to vary according to habitat features and how those species utilize those habitats across various life stages. These findings have implications for adaptive MPA management, which should be informed by the ecology and habitat preferences of target species to achieve maximum benefits for biodiversity conservation.