Search

The spatiotemporal variability of aragonite saturation state (ΩAr) has been studied in the eastern shelf of the Gulf of Cádiz (GoC) (SW Iberian Peninsula). The study was carried out during the years 2014 and 2016 aboard twelve oceanographic cruises, along three or five transects, located between Cape Trafalgar and the Guadiana River. The GoC exhibited oversaturated of calcium carbonate with ΩAr mean values of 2.68 ± 0.30 in surface and 2.05 ± 0.15 in deep waters. pH, total alkalinity (TA), calcium concentration (Ca2+) and ΩAr showed a high variability within the surface mixed layer (SML, z < 100 m). Biological activity seemed to be the main process to determine the ΩAr variability in the SML, revealing a greater importance than temperature, mixing or air-sea processes. The buffer factors of the CO2 system in the GoC have been estimated in the SML waters, and they are related with the biological activity and the temperature changes. A decrease of pH and ΩAr in this SML with depth was observed, due to the increase of the respiratory processes. In deep waters (z > 100 m), TA and Ca2+ concentration presented a conservative behaviour related to the distribution of the different water masses located in the GoC. The vertical variation of ΩAr also depends on the degree of mineralization of these water masses, obtaining the maximum values in the Subtropical North Atlantic Central Water (100–200 m), minimum values in the Subpolar North Atlantic Central Water (about 400 m), and intermediate values associated to the presence of the Mediterranean Water (>500 m). Results showed a significative acidification of the coastal areas, for those depths lower than 100 m from 2006 to 2016, with a mean decrease of pH and ΩAr of −0.0089 and −0.0552 yr−1, respectively. © 2021 The Authors, This work was funded by the Spanish CICYT (Spanish Program for Science and Technology) under the contract RTI2018-100865-B-C21 . Dolores Jiménez-López was financed by the University of Cádiz with a FPI fellowship (FPI-UCA) and Ana Sierra was financed by the Spanish Ministry of Education with a FPU fellowship (FPU2014-04048).

Threats to biodiversity and the integrity of ecological systems are escalating globally, both within and outside of protected areas. Decision makers have inadequate resources to manage all threats and typically lack information on the likely outcomes and cost‐effectiveness of possible management strategies. Priority Threat Management (PTM) is an emerging approach designed to address this challenge, by defining and appraising cost‐effective strategies for mitigating threats to biodiversity across regions. The scientific and practical impacts of PTM are increasing, with a growing number of case study applications across the globe. Here, we provide guidance and resource material for conducting the PTM process based on our experience delivering six large‐scale projects across Australia and Canada. Our handbook describes the four stages of PTM: scoping and planning; defining and collecting key elements; analysing the cost‐effectiveness of strategies; and communicating and integrating recommendations. We summarise critical tips, strengths, and limitations and scope for possible enhancements of the approach. Priority Threat Management harnesses scientific and expert‐derived information to prioritise management strategies based on their benefit to biodiversity, management costs and feasibility. The approach involves collaboration with key experts and stakeholders in a region to improve knowledge sharing and conservation support. The PTM approach identifies sets of regional level strategies that together provide the greatest benefits for multiple species under a limited budget, which can be used to inform existing processes for decision‐making. The PTM approach applies some generalisations in management strategies and resolution, in order to address complex challenges. Further developments of the approach include testing in a greater range of socioecological systems with adaptations that cater for multiobjective decisions. Synthesis and applications. Priority Threat Management is a decision science approach that brings people together to define and prioritise strategies for managing threats to biodiversity across broad regions. It delivers a prospectus for investment in the biodiversity of a region that is transparent, repeatable, participatory, and based on the best available information. Our handbook provides the necessary guidance and resources for expanding the Priority Threat Management approach to new locations, contexts, and challenges.

Distribution of N 2 O has been determined in eight cruises along three transects (Guadalquivir, Sancti Petri and Trafalgar) in the Gulf of Cadiz, during 2014 and 2015. The mean N 2 O value for this area was 10.0 ± 0.9 nM, with large spatial and temporal variations. Stratification in the water column has been observed; the concentration of this gas increases with the depth, because of the presence of the Eastern North Atlantic Central Water (ENACW) and the Mediterranean Outflow Waters (MOW). The N 2 O production measured in this study is mainly due to nitrification. N 2 O yields from nitrification were estimated from the linear correlation of the excess of N 2 O (ΔN 2 O) with Apparent Oxygen Utilization (AOU) and nitrate (NO 3 − ), with values of their slopes ranged between 0.010 and 0.021% and 0.017–0.025% respectively. There is an onshore – offshore gradient of N 2 O; the highest values were found at the shallower stations, indicating coastal input and benthic remineralization. The seawater-air flux of N 2 O is affected by several variables (temperature, AOU and NO 3 − ), and the average flux calculated is 2.7 ± 2.0 μmol m − 2 d − 1 . The fluxes show a decrease with increasing distance from the coast, and with proximity to the Strait of Gibraltar. The study area behaves as a source of N 2 O to the atmosphere, with a global emission of 0.18 Gg year − 1 .

Methane (CH4) concentrations were measured along three sections of the eastern Gulf of Cadiz (designated “Guadalquivir”, “Sancti Petri” and “Trafalgar”) during eight cruises in 2014 and 2015. The concentration of CH4 varied from 3.6 to 19.7 nmol kg− 1 (CH4 saturation percent of 122 and 916%), showing seasonal variation. The highest values were found in December 2014 and November 2015. In most of the sampling area the highest concentration of CH4 was found in subsurface waters at depths close to the thermocline, and in the bottom waters near the coast. The seawater-air flux of CH4 ranged between 0.8 and 59.7 μmol m− 2 d− 1, showing seasonal variation in function of the temperature of the surface water. In the “Guadalquivir” and “Sancti Petri” sections, the CH4 fluxes increased with proximity to the coast; this may be a result of continental inputs and CH4 emissions from sediments. The whole study area behaves as a source of CH4 to the atmosphere with mean values of 0.5 and 0.6 Gg CH4 yr− 1 in 2014 and 2015, respectively.

Climate change is likely to shift the distributions of ecosystems worldwide. Most assessments of climate change are primarily species-focused and do not directly estimate how entire ecosystems may change. Using an ecosystem-based modelling approach, we provide a region-wide climate change vulnerability assessment of the seven major ecosystems across Africa's Albertine Rift. The Albertine Rift is a global biodiversity hotspot, containing more endemic vertebrates than anywhere else in Africa. We used Maxent to estimate each ecosystem's extent using current climate data, then we projected the potential distribution of each ecosystem for 2050 and 2070. We found that suitable conditions for most ecosystems are predicted to contract rapidly in extent and shift upwards in altitude. High-altitude ecosystems and the endemic species they support are at immediate risk, owing to rapid predicted shrinkage in their suitable extent. Only the Combretum-grasslands savannah ecosystem is predicted to expand, with suitable conditions increasing by 32% in area by 2050. The extent and structure of boundary zones between the Rift's ecosystems may change significantly through time, due to the contractions and shifts of the environmental conditions for existing ecosystem distributions. By 2070, 44% of the region could be climatically unsuitable for the current ecosystems. Conservation planning across the Rift will need to account for these ecosystem shifts and rapidly changing boundary zones to ensure the long-term persistence of the many endemic species. Beyond the Albertine Rift, this ecosystem-based modelling technique can be adapted to any terrestrial region, providing critical information for conservation vulnerability assessments.

The Mar Menor is a hypersaline coastal lagoon with salinity values ranging from 41.9 to 45.5. The system is subjected to a high anthropic pressure that causes an intense eutrophication process, followed by a recovery of the macrophyte meadows. This study focuses on the distribution of the main greenhouse gases (CO2, CH4 and N2O) and was carried out in the extreme seasonal conditions of winter and summer during the year 2018. Sediment-water-atmosphere exchanges and biochemical processes in the water column appeared to be the main factors to explain the variability of these gases. Dissolved Inorganic Carbon (DIC), CH4 and N2O benthic fluxes values obtained in this study, were of 91 ± 29 mmol m-2 d-1, 3.9 ± 1.9 μmol m-2 d-1 and -0.65 μmol m-2 d-1, respectively, along with an important seasonal variation observed, with an increase of DIC and CH4 benthic fluxes during the summer season. Mean values of partial pressure of CO2 (pCO2) in surface water were of 579 μatm in winter and 464 μatm in summer, therefore we can establish that the Mar Menor acts as a source of this gas emitting 3.3 ± 3.0 mmol CO2 m-2 d-1 to the atmosphere. In spite of this, the Mar Menor has a strong autotrophic behaviour partly due to the recovery of the macrophyte meadows, presenting an estimated NEP of 101 mmol m-2 d-1. Regarding to CH4, the mean fluxes to the atmosphere were of 8.0 ± 5.8 μmol m-2 d-1 and there was evidence of CH4 production in the water column that increased in summer. Last of all, in the case of N2O the system acts as a sink with values of -0.65 ± 0.5 μmol m-2 d-1, presenting an intake of N2O that is usually detected in pristine systems.

Uniting diverse stakeholders through communication, education or building a collaborative 'common vision' for biodiversity management is a recommended approach for enabling effective conservation in regions with multiple uses. However, socially focused strategies such as building a collaborative vision can require sharing scarce resources (time and financial resources) with the on-ground management actions needed to achieve conservation outcomes. Here we adapt current prioritisation tools to predict the likely return on the financial investment of building a stakeholder-led vision along with a portfolio of on-ground management strategies. Our approach brings together and analyses expert knowledge to estimate the cost-effectiveness of a common vision strategy and on-ground management strategies, before any investments in these strategies are made. We test our approach in an intensively-used Australian biodiversity hotspot with 179 threatened or at-risk species. Experts predicted that an effective stakeholder vision for the region would have a relatively low cost and would significantly increase the feasibility of on-ground management strategies. As a result, our analysis indicates that a common vision is likely to be a cost-effective investment, increasing the expected persistence of threatened species in the region by 9 to 52%, depending upon the strategies implemented. Our approach can provide the maximum budget that is worth investing in building a common vision or another socially focused strategy for building support for on-ground conservation actions. The approach can assist with decisions about whether and how to allocate scarce resources amongst social and ecological actions for biodiversity conservation in other regions worldwide.

Insect species, especially those considered to be pests, can be exploited for human consumption. One of the most devastating pest insect species in central Mexico is the grasshopper Sphenarium purpurascens. Here we develop a sustainable exploitation strategy that produces a considerable biomass of S. purpurascens while minimising the damage they cause to agricultural fields by changing the chemical control methods to a mechanical method. In this model the biomass-per-stage of grasshoppers that can be extracted annually using the mechanical method was calculated and their potential abundance was estimated using Maxent. With a calculated population density of 10-55 individuals of S. purpurascens per m2 over approximately 1,050,000 ha of the agroecosystems in Mexico, the estimated biomass of this insect averaged 350,000 tons per year (generating a gross income of US$ 3.5×108 million). Unlike chemical control methods, mechanical control has no toxic effects on human populations or other species inside or outside of the agroecosystems. Promoting a change from chemical to mechanical control methods of pest species could greatly impact on the health of millions of people globally and on the environment, reducing carbon dioxide and methane emissions, land clearing and the use of pesticides while obtaining economic profit.

Aim To quantify the consequences of major threats to biodiversity, such as climate and land-use change, it is important to use explicit measures of species persistence, such as extinction risk. The extinction risk of metapopulations can be approximated through simple models, providing a regional snapshot of the extinction probability of a species. We evaluated the extinction risk of three species under different climate change scenarios in three different regions of the Mexican cloud forest, a highly fragmented habitat that is particularly vulnerable to climate change. Location Cloud forests in Mexico. Methods Using Maxent, we estimated the potential distribution of cloud forest for three different time horizons (2030, 2050 and 2080) and their overlap with protected areas. Then, we calculated the extinction risk of three contrasting vertebrate species for two scenarios: (1) climate change only (all suitable areas of cloud forest through time) and (2) climate and land-use change (only suitable areas within a currently protected area), using an explicit patch-occupancy approximation model and calculating the joint probability of all populations becoming extinct when the number of remaining patches was less than five. Results Our results show that the extent of environmentally suitable areas for cloud forest in Mexico will sharply decline in the next 70years. We discovered that if all habitat outside protected areas is transformed, then only species with small area requirements are likely to persist. With habitat loss through climate change only, high dispersal rates are sufficient for persistence, but this requires protection of all remaining cloud forest areas. Main conclusions Even if high dispersal rates mitigate the extinction risk of species due to climate change, the synergistic impacts of changing climate and land use further threaten the persistence of species with higher area requirements. Our approach for assessing the impacts of threats on biodiversity is particularly useful when there is little time or data for detailed population viability analyses.

Four surveys (Jun’06 and Nov’06; Feb’07 and May’07) were carried out on the northeastern shelf of the Gulf of Cádiz (southwest Iberian Peninsula) to relate the spatio-temporal distribution of the carbon cycle parameters (dissolved inorganic carbon and dissolved organic carbon) to picophytoplankton biomass and community composition. In addition, the net ecosystem production and the picophytoplankton contribution to the air-sea CO2 exchange process were investigated. The results showed that chlorophyll-a, carbon cycle parameters and picophytoplankton composition showed large seasonality, and the Guadalquivir Estuary plays an important role in the contribution of nutrient and suspended particular material over the year. Regarding picophytoplankton composition, the flow cytometry analysis demonstrated that Prochlorococcus and Synechococcus were the main populations in the studied area and their temporal and spatial distributions were complementary: the Prochlorococcus population showed its maximum concentration in May’07 and Jun’06 and in the surface oceanic water, whereas the Synechococcus population was at its maximum during Feb’07 and Nov’06, and off the Guadalquivir Estuary and Bay of Cádiz. In addition, a relationship between the studied parameters and the fugacity of CO2 was also observed, suggesting that primary production is an important factor in the regulation of this parameter in the studied area. The calculated carbon budget showed that the area acts as a carbon sink on an annual basis. Se llevaron a cabo cuatro campañas oceanográficas (Jun’06 y Nov’06; Feb’07 y May’07) en la plataforma continental noreste del golfo de Cádiz (suroeste de la península Ibérica) para relacionar la distribución espacio-temporal de los parámetros del ciclo del carbono (carbono inorgánico disuelto y carbono orgánico disuelto) con la biomasa picofitoplanctónica y la composición de la comunidad. Además, se investigó la producción neta del ecosistema y la contribución del picofitoplancton al proceso de intercambio atmósfera-agua de CO2. Los resultados mostraron que la clorofila-a, los parámetros del ciclo del carbono y la composición del picofitoplancton presentaron una gran estacionalidad, jugando el estuario del Guadalquivir un papel importante en la contribución de nutrientes y material particulado en suspensión a lo largo del año. Los análisis de citometría demostraron que Prochlorococcus y Synechococcus fueron las principales poblaciones en el área de estudio y que su distribución espacial y temporal fue complementaria: Prochlorococcus presentó la máxima concentración en primavera y verano en aguas superficiales oceánicas, mientras que Synechococcus en invierno y otoño en aguas someras. Además, se observó una relación entre los parámetros estudiados y fugacidad de CO2, lo que sugiere que la producción primaria es un factor importante en la regulación de este parámetro en el área de estudio. El balance de carbono calculado indicó que el área actúa como sumidero de carbono a escala anual.

Tropical montane cloud forests are among the most vulnerable terrestrial ecosystems to climate change(1-3) owing to their restricted climatic requirements and their narrow and fragmented distribution(4). Although 12% of Mexican cloud forest is protected, it is not known whether reserves will ensure the persistence of the ecosystem and its endemic species under climate change. Here, we show that 68% of Mexico's cloud forest could vanish by 2080 because of climate change and more than 90% of cloud forest that is protected at present will not be climatically suitable for that ecosystem in 2080. Moreover, if we assume unprotected forests are cleared, 99% of the entire ecosystem could be lost through a combination of climate change and habitat loss, resulting in the extinction of about 70% of endemic cloud forest vertebrate species. Immediate action is required to minimize this loss-expansion of the protected-area estate in areas of low climate vulnerability is an urgent priority. Our analysis indicates that one key area for immediate protection is the Sierra de Juarez in Oaxaca. This area supports many endemic species and is expected to retain relatively large fragments of cloud forest despite rapid climate change.

10 pages, 8 figures, 2 tables, [EN] The coupling between the thermohaline, chemical and biological variables on the northeast continental shelf of the Gulf of Cádiz was determined during the Emigas I survey in summer 2006. Samples were collected to chemically characterize the different water types and to analyze the chlorophyll a distribution. Four different water masses were identified: North Atlantic Central Water (NACW), Surface Atlantic Water (SAW), considered a modification of NACW, and South and North Surface Waters. The highest nutrient levels were found in subsurface NACW, while surface waters were almost nutrient-depleted except in the Guadalquivir region. The isopycnal level of 26.3 kg m-3 marked the limit between nutrient-rich NACW and nutrient-poor surface waters. At the offshore stations, the subsurface cholorophyll a maximum was located at the depth of nitracline and associated with the 26.3 kg m-3 isopycnal level rather than with the pycnocline depth. At the inshore stations, chlorophyll a maxima were observed at the bottom, except for the surface maximum in the River Guadalquivir region., [ES] Durante el verano 2006 se llevó a cabo una campaña oceanográfica en la parte NE de la plataforma continental del Golfo de Cádiz para determinar el acoplamiento de las variables termohalinas, químicas y biológicas. En cada estación se tomaron muestras para la caracterización química de las diferentes masas de agua y el análisis de la distribución de clorofila-a. Se diferenciaron cuatro tipos distintos de masas de agua: North Atlantic Central Water (NACW); Surface Atlantic Water (SAW), que es una modificación de la primera y las aguas superficiales del Norte y del Sur. Las concentraciones más elevadas de nutrientes se encontraron asociadas con las aguas profundas (NACW); en cambio las aguas superficiales estaban prácticamente agotadas en nutrientes, con excepción de las estaciones próximas a la desembocadura del Río Guadalquivir. El límite entre NACW rica en nutrientes y las aguas con bajas concentraciones de nutrientes fue establecido en el nivel isopícnico de 26.3 kg m-3. Para las estaciones exteriores, el máximo subsuperficial de clorofila-a no se encontró en la posición de la picnoclina sino en la de la nitraclina, asociado al nivel isopícnico de 26.3 kg m-3. Para las estaciones interiores, el máximo de clorofila se localizó cerca del fondo, con excepción de la región del Río Guadalquivir, donde se observó un máximo superficial, This work was supported by the Spanish CICYT (Spanish Commission for Research and Development) under contract CTM2005-01364/MAR. E.A. was funded by a grant from the Spanish MECD, we also thank the research project from the Junta de Andalucia PO7-RNM01397.