Assessing the vulnerability of marine life to climate change in the Pacific Islands region

Giddens J, Kobayashi DR, Mukai GNM, Asher J, Birkeland C, Fitchett M, et al.

Summarized by Habiba Rabiu, a student of environmental geosciences at Fort Hays State University. Habiba is interested in all aspects of environmental science and conservation & sustainability. She would like to work in educating others about those topics. In her free time, she likes to read, write, and bake.

What data were used? The researchers assessed 83 species grouped into six functional groups based on range size and habitat: pelagic, shark, deep-slope, coastal, coral reef, and invertebrate species. The “coral reef” group of fishes contained many species, so it was further divided into JEGS (Jacks, Emperors, Groupers, Snappers), parrotfishes, surgeon fishes, and “other coral reef” fishes. The species were chosen based on expert opinion, importance of their ecosystem function, records of food fish, and cultural and conservation importance. The species came from a wide range of locations in the Central, West, and South Pacific Ocean. 

To determine the climate change vulnerability of the species, the researchers considered two components: exposure and sensitivity. Exposure was defined as to what degree an organism is likely to experience a negative change in a particular physical variable. Sensitivity was considered a biological trait-based variable, which the researchers determined by review of existing literature and expert opinion. 

Methods: To assess exposure, data from various sources was compiled based on certain variables that were the most significant for species living in the Pacific Islands Region: temperature (surface and bottom), salinity (surface and bottom), ocean acidification (pH), mixed layer depth, precipitation, current velocity, wind stress, surface oxygen, sea level rise, wave height, chlorophyll, and primary productivity. To determine sensitivity, experts were asked to identify the six most important sensitivity attributes for each species out of 12: habitat specificity; prey specificity, complexity in reproductive strategy, sensitivity to ocean acidification, early life history survival and settlement requirements, dispersal of early life stages, sensitivity to temperature, population growth rate, stock size/status, adult mobility, spawning cycle, and other stressors (including habitat degradation, pollution, disease, or changes in the food web). 

For each species, a component score was calculated for both exposure and sensitivity based on the number of factors/attributes that passed a certain threshold. Then, the overall climate change vulnerability rank was calculated by multiplying the exposure and sensitivity component scores. The numerical values for the climate vulnerability rank were the following: 1–3 (low), 4–6 (moderate), 8–9 (high), and 12–16 (very high).

Results: All species ranked “very high” in the overall exposure component of vulnerability. It was determined that this was caused by three influences: decrease in oxygen concentration, rise in sea surface temperature, and increase in ocean acidification (decrease in surface pH). In the sensitivity component, it was found that the groups that were made up of larger-bodied species shared similar sensitivity scores, while the groups with smaller and site-attached species tended to differ.

In the overall assessment of climate change vulnerability, the species showed a wide range in vulnerability across the functional groups. The larger and more wide-ranging pelagic and coastal species were scored as the least vulnerable, while the smaller and more site-attached species (small coral reef fishes and invertebrates) were the most vulnerable. Some groups had a more general ranking across all the included species (for example in the coastal group all the species were ranked as “moderate”), while in others there was a wider distribution across vulnerability rankings. 

Why is this study important? Most studies on the effect of climate change of ocean ecosystems focus on a particular or particular type of species, or on singular factors. This study assessed many factors affecting many species, which creates a more all-encompassing view of the effects of climate change and enables focus on the ecosystem as a whole rather than looking at it in pieces. 

The big picture: Well-functioning ocean ecosystems are essential to the health of the planet, but there is still a lack of both information about the ecosystems and the organization and usage of that information. Collecting data on marine species and the environmental factors that affect them (and to what degree) is necessary to their preservation.

Citation: Giddens J, Kobayashi DR, Mukai GNM, Asher J, Birkeland C, Fitchett M, et al. (2022) Assessing the vulnerability of marine life to climate change in the Pacific Islands region. PLoS ONE 17(7): e0270930. https://doi.org/10.1371/journal.pone.0270930

Effect of environmental education on the knowledge of aquatic ecosystems and reconnection with nature in early childhood

Maria João Feio, Ana Isabel Mantas, Sónia R. Q. Serra, Ana Raquel Calapez, Salomé F. P. Almeida, Manuela C. Sales, Mário Montenegro, Francisca Moreira

Summarized by Habiba Rabiu, a student of environmental geosciences at Fort Hays State University. Habiba is interested in all aspects of environmental science and conservation & sustainability. She would like to work in educating others about those topics. In her free time, she likes to read, write, and bake.

What data were used? In 2018, the environmental educational project CresceRio was created in the city of Coimbra, Portugal, to encourage the populace to reconnect with nature, preserve and protect the streams found in the area, and teach children about the importance of the streams and preserving green and blue (terrestrial and aquatic) ecosystems. Most children who live in the city had little exposure to nature and expressed fear and incorrect knowledge about the streams and rivers in their area. It was proposed that introducing field trips to natural areas and hands-on activities to school curriculums would be a low cost yet effective way to improve their relationship with the natural world. 

Methods: Over the course of 14 months, the researchers conducted several surveys with a class of 24 students (aged 5–6 at the beginning of the program). At particular intervals (labeled M), the children were questioned about five main topics: their identification and background, their awareness of streams and rivers, their recognition of the biodiversity that existed in the rivers, their awareness of various factors negatively affecting the rivers, and their awareness of the ecosystem services provided by rivers to the population. 

M1 occurred at the beginning of the program (September 2018) and was followed the next month by a trip to a stream outside of the city that was not seriously affected by urban activity. M2 occurred in November 2018, and the students visited an urban stream that was visibly affected by urban activity including construction, removal of trees, and litter. In February 2019, the students participated in a laboratory class where they examined fallen leaves and were taught to identify various invertebrates and algae using microscopes. M3 took place in March 2019, followed by a workshop in June 2019 where they reviewed photos and videos and discussed what they learned from their previous activities. In October 2019 they visited another urban stream that was slightly less altered than the one they visited before. The last survey was conducted in November 2019 and was done in the form of group interviews. 

Results: The three main takeaways that the researchers identified were 1) that children in urban areas have little contact with or knowledge of nature, 2) after a year of exploring the streams and their ecosystems their knowledge increased (both about the ecosystems and the problems they face) and their fears decreased, and 3) the long duration of the program was key as changes in their attitude and knowledge only became clear after a few activities.

In all five categories explored (personal background and experience, awareness of aquatic ecosystems, recognition of biodiversity, awareness of issues affecting rivers, and awareness of services provided by rivers) the students showed increased interest and cognizance of the streams by the end of the program. Students were more aware of the streams close to where they live as well as the animals (other than fish) that lived there, such as birds and insects. The activities and field trips lessened their fears of imaginary creatures or animals like alligators that did not exist in Portuguese rivers and made them more appreciative of the streams as a resource for water and recreation. They also acknowledged the presence of trees on the banks of the streams that provided oxygen, shelter, and food for animals. The children also showed an increased negativity for litter, lack of trees, too many reeds (that grow unchecked when trees are removed and choke the stream) and too many buildings around the streams. The students were also reported as saying that they would not litter and would discourage others from doing so as well.

Why is this study important? Children growing up in urban areas are exposed to various pollutants and obstacles that come from living in the city. Being consistently exposed to nature from an early age can help to combat those negative effects and promote health and wellbeing. Additionally, learning about the importance of aquatic ecosystems naturally inspires children to be interested in conservation and sustainability. This study showed that when given the opportunity to have real experiences in nature, they form their own positive opinions and ideas.

The big picture: Conservation of green and blue ecosystems is dependent on future generations having genuine understanding of and connections to nature. Introducing environmental studies, complete with hands-on activities, to primary education curriculums is an effective way to nurture those connections. Children should be exposed to the natural spaces close to their schools and homes in order to feel connected to nature and have a deeper learning experience.

Citation: Feio MJ, Mantas AI, Serra SRQ, Calapez AR, Almeida SFP, et al. (2022) Effect of environmental education on the knowledge of aquatic ecosystems and reconnection with nature in early childhood. PLOS ONE 17(4): e0266776. https://doi.org/10.1371/journal.pone.0266776

The relationship between biodiversity and wetland cover varies across regions of the conterminous United States

Jeremy S. Dertien, Stella Self, Beth E. Ross, Kyle Barrett, and Robert F. Baldwin

Summarized by Habiba Rabiu, a student of environmental geosciences at Fort Hays State University. Habiba is interested in all aspects of environmental science and conservation & sustainability. She would like to work in educating others about those topics. In her free time, she likes to read, write, and bake.

What data were used? Using data from the National Wetlands Inventory and the National Land Cover Database, the researchers modeled wetland cover for the conterminous (continental 48) United States and collected estimates for how much wetland existed in the continental U.S. in 2001 and 2011. From various other sources they compiled more information essential to understanding wetland habitats: which animal species live in the areas and their distribution/ranges, the average temperatures and precipitation levels of the wetlands, and the elevation or altitude. 

Methods: The maps showing the ranges of the endemic (native) birds, mammals, reptiles, and amphibians were accumulated into one endemics raster (a grid where each cell represents a piece of data) for analysis. Each cell represented a 10×10 km area, so the estimated amount of wetland cover (in hectares) per every 100 km² was the focus. Wetlands smaller than 0.01 hectares and large bodies of water were removed from the data to prevent flawed or biased results. 

To calculate wetland change, the researchers subtracted the wetland cover estimates of 2011 from the 2001 coverage to calculate the 10-year change. To calculate per-cell percentage change of wetland cover they divided the 2001 wetland cover per cell by the estimate of 10-year wetland change.

Results: The proportional wetland cover varied from 0.0 to 5841.0 ha/100 km² across all 48 states considered. The area with the most wetland cover was the southeastern U.S. including portions of Alabama, Georgia, Florida, and North and South Carolina. The three areas with significant percentages of wetland cover were Florida, particularly in the northern part of the state and in the Everglades National Park, the floodplain of the Mississippi Valley, and parts of northern Minnesota and Wisconsin. The western U.S. had the least wetland cover with areas of less than 100 ha/100 km² in the Mojave and Sonoran Deserts. Between 2001 and 2011, wetland coverage decreased by approximately 481,500 ha. The highest percentage of loss was in the Great Plains region.

The models for the four animal groups showed regional hotspots where proportional wetland cover was positively or negatively correlated with species diversity. There was no consistent relationship between wetland cover and species variety across the entire 48 states, but on a regional scale there were correlations. Birds, reptiles, and endemic species groups all showed large areas of positively significant correlation with wetland cover while mammals and reptiles showed relatively larger negatively significant correlations.

Why is this study important? While wetlands all over the United States should be protected, certain areas are in a more delicate balance than others simply due to how many organisms rely on them. Knowing which regions have the most wetland cover and biodiversity can indicate where efforts of conservation and restoration should be particularly focused to have the most valuable impact. 

The big picture: Wetlands are important habitats and migratory stops for wildlife and provide essential services to the environment including carbon sequestration, water filtration, nutrient retention, and flood mitigation. The loss of wetlands in the U.S. to human activity and urban development has already been significant. The prevention of further damage has to begin with providing clear and concise information about the wetlands and the resources they provide. 

Citation: Dertien JS, Self S, Ross BE, Barrett K, Baldwin RF (2020) The relationship between biodiversity and wetland cover varies across regions of the conterminous United States. PLoS ONE 15(5): e0232052. https://doi.org/10.1371/journal.pone.0232052

Climate change effects on desert ecosystems: A case study on the keystone species of the Namib Desert Welwitschia mirabilis

By Pierluigi Bombi, Daniele Salvi, Titus Shuuya, Leonardo Vignoli, Theo Wassenaar

Summarized by Habiba Rabiu, a student of environmental geosciences at Fort Hays State University. Habiba is interested in all aspects of environmental science and conservation & sustainability. She would like to work in educating others about those topics. In her free time, she likes to read, write, and bake.

What data were used? The welwitschia dwarf tree is a gymnosperm native to the Namib desert. It is considered a keystone species of the region, providing food, water, and shelter for the animals that live in the desert. Under the current threat of climate change, there is concern that certain parts of the welwitschia’s distribution range will no longer be suitable for their survival. 

Methods: The researchers spent ten days searching for W. mirabilis plants in the northernmost area of their traditional range. They recorded the plant locations (precise coordinates of the plant), health condition (based on leaf color to measure photosynthesis efficiency and chlorophyll content, using the classifications of good, average, poor and dead), reproductive status (whether or not the plant had cones), and plant size (diameter of the stem and leaf length) for each individual plant. Because the plants grow in clusters of four to 400, called stands, they recorded the proportion of healthy, average, poor, and dead plants in each stand, as well as the average size of the plants in each stand and proportion of reproductive to non-reproductive plants. 

Results: A total of 1330 welwitschia plants were found in 12 stands, across an area of about 215 km². The researchers found that that to be significantly smaller than what was previously considered their area of distribution. 

With regards to health conditions, most of the plants (50% total, 32–74% average in each stand) were considered ‘average’. Plants considered to be in ‘poor’ condition were 32% (range: 11–50%), those in ‘good’ condition were 10% (range: 0–30%) and seven percent of the plants were dead (range: 0–30%). Concerning reproductive status, 56% of the plants (range: 10–90% across the different stands) had cones. Size of the plants varied greatly when considered individually and in each stand. 

The overall status of the plants was considered consistent with their expected condition when taking into account the effects of climate change. The results suggested that ongoing climate change is negatively affecting the health status of welwitschia populations in the area and causing a reduction of the species’ distribution.

Why is this study important? Welwitschia trees are essential to the Namib desert ecosystems and are good indicators for the overall health of the environment. Determining how they are responding to climate change could indicate what the future of the region will look like for the organisms that live there.

The big picture: While deserts are not usually thought of as teeming with life, they are important environments that house a lot of biodiversity in the form of plants and animals. The effects of global warming are and will continue to be particularly harsh on desert species. The ecosystems that exist there have to adapt to increasing temperatures that were already high to begin with, less rainfall where there was already very little, and more CO₂ in the atmosphere. These changes could greatly affect how the deserts all over the world function and whether or not the organisms that survive there will be able to continue to do so.

Citation: Bombi P, Salvi D, Shuuya T, Vignoli L, Wassenaar T (2021). “Climate change effects on desert ecosystems: A case study on the keystone species of the Namib Desert Welwitschia mirabilis.” PLOS ONE 16(11): e0259767. https://doi.org/10.1371/journal.pone.0259767

Population size, density, and ranging behaviour in a key leopard population in the Western Cape, South Africa

Lana Müller, Willem Daniel Briers-Louw, Barbara Catharine Seele, Christiaan Stefanus Lochner, Rajan Amin

Summarized by Habiba Rabiu, a student of environmental geosciences at Fort Hays State University. Habiba is interested in all aspects of environmental science and conservation & sustainability. She would like to work in educating others about those topics. In her free time, she likes to read, write, and bake.

What data were used? The researchers chose an area in the Cederburg Mountains in Western Cape, South Africa, about 200 km north of Cape Town. In the Western Cape Province, there is about 50,000 km² of potential leopard habitat, but only 30% of it is in conservation areas or mountain catchment zones. The density of the leopard population in the province is among the lowest in the country with only 0.25–2.3 individuals per 100 km2, however their home ranges are relatively large (35–910 km²). The aim was to determine the number of individual leopards in the region and the amount of land they occupy.

Methods: The area of study chosen was 2,823 km² in size and 73 camera traps were set up with a mean distance of 2.78 km between each trap. The cameras were placed along any trails or natural features that the leopards were likely to come across or had shown evidence of having already been there. The cameras operated 24 hours a day and took three images each time they were motion-triggered. From the pictures taken, the leopards were manually identified and digitally differentiated using a software that could distinguish each leopard’s unique spotted pattern. 

In addition to the pictures, the researchers also used various software and databases to track the population size and density, site use, and ranging habits of the leopard population, as well as any livestock depredation (or attacks) that occurred. This information contributed to creating a more complete picture of the leopards in the area and their movements. One topic that required special attention was the difference between the leopard movements in winter versus the summer, as the changing seasons had a significant effect on how far the leopards had to move for food and other resources.

Results: From the photographs taken, 63 adult leopards were identified (31 females, 26 males, and 6 of unknown sex.) In the summer, the leopard density was estimated to be 1.62 leopards per 100 km² and more concentrated towards the center of the study area, while in the winter the leopards were more spread out, causing the density to decrease to 1.53 leopards per 100 km². In both seasons, leopard density was higher in females with a female to male ratio of 2.42:1 in the summer and 2.45:1 in the winter.

The leopards were found to be present in nearly the entire area studied, with a total of 2,638 pictures being taken of them at 95% of the camera traps. The habitat type and altitude of the different parts of the study area did not seem to make a difference in the leopards’ movement. As could be inferred from the density measurements, the female leopards tended to keep their activity within a smaller radius around the center of the study area, occupying an average space of 117 km² in the summer and 182 km² in the winter, while the male leopards had an average range of 456 km² in the summer and 856 km² in the winter. The average number of instances of livestock attacks did not appear to differ in number from previous research. The mean number of livestock killed was 7.7 during the summer and 14.9 during the winter.

Why is this study important? This research is a thorough study of the leopard population in the Cederburg Mountain region that employed several methodologies and programs. It supports previous research regarding the average low density (less than 2 leopards per 100 km2) of the leopard population in the Eastern and Western Cape Provinces of South Africa. 

The big picture: Since 2016, leopards have been listed as Vulnerable on the International Union for Conservation of Nature’s Red List. This status is due to a variety of factors, many of which are anthropogenic, or human caused, including habitat loss, loss of food sources, poaching for sale or body parts, and killing by farmers attempting to protect their livestock. Tackling issues of conserving threatened animals requires precise data about the animals’ population and activity.

Citation: Müller L, Briers-Louw WD, Seele BC, Stefanus Lochner C, Amin R (2022) Population size, density, and ranging behaviour in a key leopard population in the Western Cape, South Africa. PLOS ONE 17(5): e0254507. https://doi.org/10.1371/journal.pone.0254507

Small and slow is safe: On the drought tolerance of tropical tree species

Joannès Guillemot, Nicolas K. Martin-StPaul, Leticia Bulascoschi, Lourens Poorter, Xavier Morin, Bruno X. Pinho, Guerric le Maire, Paulo R. L. Bittencourt, Rafael S. Oliveira, Frans Bongers, Rens Brouwer, Luciano Pereira, German Andrés Gonzalez Melo, Coline C. F. Boonman, Kerry A. Brown, Bruno E. L. Cerabolini, Ülo Niinemets, Yusuke Onoda, Julio V. Schneider, Serge Sheremetie, Pedro H. S. Brancalion

Summarized by Habiba Rabiu, a student of environmental geosciences at Fort Hays State University. Habiba is interested in all aspects of environmental science and conservation & sustainability. She would like to work in educating others about those topics. In her free time, she likes to read, write, and bake. 

What data were used? In this study, data concerning 601 tree species were examined. To determine what characteristics of a tree would make it more drought resistant, three qualities were assessed: resistance of xylem to embolism, which is the blocking of water from moving through the plant (designated as P50 by the authors), leaf turgor loss point or the ability of a plant to maintain turgor pressure and operate under water stress (TLP), and the hydraulic safety margin (HSM) which is the risk that a plant will experience hydraulic failure in the driest conditions it could normally face. HSM can also be defined as the difference between turgor loss point and resistance to embolism (HSM=TLP-P50).

The researchers compiled data from previous meta-analyses on the TLP and P50 values of the chosen tree species. The species were further divided based on leaf habit, meaning whether they were evergreen or deciduous. Additionally, seven traits of the species were considered: leaf mass per area (LMA), leaf size, leaf nitrogen concentration (leaf N), leaf phosphorus concentration (leaf P), wood density, maximum height, and seed mass. The type of forest the species lived in, whether dry or moist, was also a factor that was considered.

Methods: To organize these data in a way that would allow classification of the tree species based on drought resistance, the researchers found two major axes (traits) that contributed to drought resistance. The most important factor (labeled the “fast-slow” axes) showed the difference in rate of resource attainment and processing between the tree species. The second most important factor was the “stature-recruitment” axes, which compared the relationship between preference for (that is more energy and resources are allotted to) growth and survival of individual plants, to preference for new seedling propagation.

LMA, wood density, and leaf N and leaf P concentrations are features that determine where the species falls on the fast-slow axes, while maximum height, seed mass, and leaf size indicate their position on the stature-recruitment axes. TLP and P50 values (plus the calculated HSM values) demonstrate how well the species respond to lack of water and the accompanying stress. Lower values of HSM, TLP, and P50 (which are expressed as negative numbers) indicate more drought resistance.

Results:  The research determined that TLP and P50 (blocking of hydraulic action and the ability of the plant to maintain water pressure) were more negative in dry forests, and evergreen species tended to exhibit more negative TLP and smaller TLP- based HSM (risk that a plant will experience hydraulic failure) in dry forests than deciduous forests. The species that had the more negative TLP/P50 values and smaller HSM values tended to be smaller (leaned more to the recruitment side of the “stature-recruitment” axes) and slower to get and use resources (leaning towards “slow” rather than “fast” on those axes). In other words, smaller and slower evergreen trees were more drought resistant, and dry forests were naturally better suited to survive water stress than moist ones. 

Why is this study important? One significant takeaway from this study is that it shows that drought resistance is not an independent quality that can be assessed on its own, it’s a complex mix of many traits. Isolating which traits are possessed by the most drought-resistant trees is valuable information when contending with ecosystems that are becoming hotter and drier as global warming becomes a bigger threat.

The big picture: Planting trees to restore tropical forests could be a great tool to combat the ill effects of climate change. However, care has to be taken to ensure that the trees planted are equipped to deal with the increased temperature of the atmosphere and presence of greenhouse gasses that come with global warming. 

Citation: Guillemot, J., Martin- StPaul, N. K., Bulascoschi, L., Poorter, L., Morin, X., Pinho, B. X., le Maire, G., Bittencourt, P. R. L., Oliveira, R. S., Bongers, F., Brouwer, R., Pereira, L., Gonzalez Melo, G. A., Boonman, C. C. F., Brown, K. A., Cerabolini, B. E. L., Niinemets, Ü., Onoda, Y. Schneider, J. V., … Brancalion, P. H. S. (2022). Small and slow is safe: On the drought tolerance of tropical tree species. Global Change Biology, 28, 2622– 2638. https://doi.org/10.1111/gcb.16082

A century of warming on Caribbean reefs

Colleen B. Bove, Laura Mudge, and John F. Bruno

Summarized by Habiba Rabiu, a student of environmental geosciences at Fort Hays State University. Habiba is interested in all aspects of environmental science and conservation & sustainability. She would like to work in educating others about those topics. In her free time, she likes to read, write, and bake. 

What data were used? The researchers compiled data from three ocean temperature databases (HadISST, Pathfinder, and OISST) to assess changes in sea surface temperature (SST) and marine heatwave (MHW) occurrences in coral reefs situated in the Caribbean from 1871 to 2020. These data consisted of both in situ readings (those that were taken directly at the surface of the water from boats or buoys) and remote satellite readings. 

Methods: Using data from multiple sources, the researchers determined the locations of 5,326 coral reefs in the Caribbean. Referring to the World Wildlife Fund marine ecoregion classifications, these reefs were sorted into 8 ecoregions. From these data, they assessed the SST for the Caribbean basin as a whole, each ecoregion, and the individual reefs. They also assessed the frequency and duration of MHV events (periods of time, lasting at least five days, when the temperature of a marine area is abnormally high for that location and time) in the basin and the reefs. 

Results: Over the past 150 years, Caribbean coral reefs have warmed by 0.5-1˚C. As a whole, the Caribbean basin has experienced an increase of temperature at a rate of 0.04˚C per decade since 1871 and 0.17˚C per decade since 1981. The rate of increase in each ecoregion differed slightly, with the most recent measurements describing a range from an increase of 0.17˚C per decade in the Bahamian ecoregion to 0.26˚C per decade in the Southern and Eastern Caribbean ecoregions. 

 The frequency and duration of MHW have also increased, particularly since 2010. In the 1980s, MHW occurred once a year on average, which increased to an average of five times a year in the 2010s. This has drastically decreased the return time of the MHW events (the number of days between each event.) In the 1980s an average of 377 days elapsed between each MHW, while in the 2010s, an average of 111 days of return time was recorded. Additionally, recent MHW events have lasted for an average of 14 days compared to the 1980s when they typically lasted less than 10.

Why is this study important? Oceans make up the majority of the Earth’s surface, and the organisms that live there are being greatly affected by global warming and other degradational occurrences in the environment such as sewage pollution and pesticide runoff. Coral reefs are especially rich in biodiversity and contribute greatly to the overall health of the oceans. Given that most marine animals species are ectothermic (they have little to no internal/physiological control of heat and rely on their environment to regulate their temperature), drastic changes in temperature can affect their metabolism, alter their growth rates and caloric needs, cause disease outbreaks, and in some cases lead to the loss of a species entirely which further disrupts the food webs and other delicate systems of the ecosystem. 

The big picture: There are several factors that are causing the destruction of coral reefs, including overfishing (and other human activities), pollution, and overabundance of macroalgae (which thrives in warmer waters), but marine temperature increase has proven to be a primary factor, mainly due to how it causes coral bleaching (when algae is forcibly expelled from the coral, leaving it vulnerable). This is important because it shows that coral reefs are not only affected by regional and local activity, but also by global warming that is largely caused by the activity of first world countries, even if they are not necessarily close to the areas being affected. Halting the ruin of the reefs and other complex ecosystems will require global attention and effort, particularly from more populous, technologically advanced regions that use the greenhouse gasses that are increasing the temperature of the Earth’s surface.

Citation: Bove CB, Mudge L, Bruno JF (2022) A century of warming on Caribbean reefs. PLOS Climate 1(3): e0000002. https://doi.org/10.1371/journal.pclm.0000002