Interface processes between protected and unprotected areas: A global review and ways forward

Land‐use changes and the expansion of protected areas (PAs) have amplified the interaction between protected and unprotected areas worldwide. In this context, ‘interface processes' (human–nature and cross‐boundary interactions inside and around PAs) have become central to issues around the conservation of biodiversity and ecosystem services. This scientific literature review aimed to explore current knowledge and research gaps on interface processes regarding terrestrial PAs. At first, 3,515 references related to the topic were extracted through a standardized search on the Web of Science and analyzed with scientometric techniques. Next, a full‐text analysis was conducted on a sample of 240 research papers. A keyword analysis revealed a wide diversity of research topics, from ‘pure' ecology to sociopolitical research. We found a bias in the geographical distribution of research, with half the papers focusing on eight countries. Additionally, we found that the spatial extent of cross‐boundary interactions was rarely assessed, preventing any clear delimitation of PA interactive zones. In the 240 research papers we scanned, we identified 403 processes that were studied. The ecological effects of PAs were well documented and appeared to be positive overall. In contrast, the effects of PAs on local communities were understudied and, according to the literature focusing on these, were very variable according to local contexts. Our findings highlight key research advances on interface processes, especially regarding the ecological outcomes of PAs, the influence of human activities on biodiversity, and PA governance issues. In contrast, main knowledge gaps concern the spatial extent of interactive zones, as well as the interactions between local people and conservation actions and how to promote synergies between them. While the review was limited to terrestrial PAs, its findings allow us to propose research priorities for tackling environmental and socioeconomic challenges in the face of a rapidly changing world.     

Distribution patterns of benthic diatoms in a Pampean river exposed to seasonal floods: the Cuarto River (Argentina)

The diatom community growing on cobbles and sand substrata along the Cuarto River (Córdoba, Argentina) was studied during 2000 and 2001. Multivariate analyses of the data (PCA and CCA) showed distinct differences in water chemistry and substrata types between the upstream sites (sites 1–10) and downstream sites (sites 11–19). Sites 1–10 supported an epilithic diatom community associated with low water conductivity and gravel substrata. This consisted of adnate Achnanthes (A. biasolettiana, A. minutissima), as well as stalked (Gomphonema aff. angustum, Reimeria uniseriata, Fragilaria capucina var. rumpens) or prostrate (Nitzschia lacuum) taxa. Downstream sites were associated with high conductivity, fast flowing waters and finer substrata (sand, silt), and were colonised by prostrate diatoms, including several species of Navicula (N. pupula, N. mutica, N. veneta, N. insociabilis) and Nitzschia (N. umbonata, N. palea). Variations in water flow caused significant changes in the diatom communities of the river. During periods of low flow (winter and autumn), chain forming (Diatoma vulgaris, D. moniliformis) or stalked (Synedra ulna) taxa partially replaced the former community of Navicula and Nitzschia in the downstream sites. High flow (in summer) led to diatoms of large size being replaced by smaller size diatoms, such as Achnanthes lanceolata, Navicula mutica, Hantzschia amphioxys and Amphora montana. The severe effect of floods in the lower part of the Cuarto led to these taxa having a much higher proportion in the lower stretch of the river, taking advantage of the subaerial conditions created by the floods. Local episodes of water pollution were associated with a transient shift towards the dominance of Navicula pupula, Synedra ulna, Nitzschia lacuum and Reimeria uniseriata during winter, when inputs were least diluted because of the low flow.     

Chemical and Physical Environmental Conditions Underneath Mat- and Canopy-Forming Macroalgae,and Their Effects on Understorey Corals

Disturbed coral reefs are often dominated by dense mat- or canopy-forming assemblages of macroalgae. This study investigated how such dense macroalgal assemblages change the chemical and physical microenvironment for understorey corals, and how the altered environmental conditions affect the physiological performance of corals. Field measurements were conducted on macroalgal-dominated inshore reefs in the Great Barrier Reef in quadrats with macroalgal biomass ranging from 235 to 1029 g DW m⁻² dry weight. Underneath mat-forming assemblages, the mean concentration of dissolved oxygen was reduced by 26% and irradiance by 96% compared with conditions above the mat, while concentrations of dissolved organic carbon and soluble reactive phosphorous increased by 26% and 267%, respectively. The difference was significant but less pronounced under canopy-forming assemblages. Dissolved oxygen declined and dissolved inorganic carbon and alkalinity increased with increasing algal biomass underneath mat-forming but not under canopy-forming assemblages. The responses of corals to conditions similar to those found underneath algal assemblages were investigated in an aquarium experiment. Coral nubbins of the species Acropora millepora showed reduced photosynthetic yields and increased RNA/DNA ratios when exposed to conditions simulating those underneath assemblages (pre-incubating seawater with macroalgae, and shading). The magnitude of these stress responses increased with increasing proportion of pre-incubated algal water. Our study shows that mat-forming and, to a lesser extent, canopy-forming macroalgal assemblages alter the physical and chemical microenvironment sufficiently to directly and detrimentally affect the metabolism of corals, potentially impeding reef recovery from algal to coral-dominated states after disturbance. Macroalgal dominance on coral reefs therefore simultaneously represents a consequence and cause of coral reef degradation.     

Ketanserin in the treatment of traumatic vasospastic disease.

The specific serotonin receptor blocker ketanserin was given orally to 12 patients with traumatic vasospastic disease in a double blind crossover study. The effect of treatment was assessed by measuring finger systolic pressure and rewarming time after cold provocation and by medical interview and diaries. Median (range) percentage change in finger systolic pressure after cooling was 50 (0-100)% after treatment with ketanserin compared with 0 (0-90)% after placebo. Median (range) rewarming time after cooling decreased from 320 (236-972)s with placebo to 160 (88-404)s after treatment with ketanserin. These changes were not significant. Ninety five percent confidence intervals for difference between the treatments, however, showed that finger systolic pressure may be 80% better and rewarming time 256 seconds faster after treatment with ketanserin than after placebo. The number of attacks did not differ significantly between the two treatments. Two patients had a feeling of warmth in their hands during treatment with ketanserin. The results suggest that orally administered ketanserin may improve digital circulation in patients with traumatic vasospastic disease, but larger numbers of patients are required to assess the true effect of treatment with ketanserin in this disease.     

Control of glycolysis in magnesium deficiency: studies on intact red cells and hemolysates]

The behaviour of glycolytic flux and glycolytic metabolic concentrations was studied under conditions of magnesium deficiency. The Mg-deficiency was produced in whole animals (rats) by feeding a diet almost completely free of Mg and in hemolysates of men by the addition of a chelating agent. The results show that the decrease of the free Mg-level is diminished by partial destruction of ATP and 2,3-DPG. The analysis of the control strength of the overall flux leads to the conclusion that the decrease of the glycolytic rate is caused by an inhibition of the hexokinase-phosphofructokinase-control system. The decrease of the MgATP-Complex and free Mg++-level explains the diminished phosphorylation of glucose by the hexokinase. The ATP-inhibition of the phosphofructokinase is amplified by a small increase of free ATP-concentration and a simultaneous decrease of the Fru-6P-level. The increase of the PEP-level is caused by the diminished free Mg++ and MgATP-complex and does not demonstrate a larger control strength of the pyruvate kinase.     

The other ocean acidification problem: CO2 as a resource among competitors for ecosystem dominance

Predictions concerning the consequences of the oceanic uptake of increasing atmospheric carbon dioxide (CO₂) have been primarily occupied with the effects of ocean acidification on calcifying organisms, particularly those critical to the formation of habitats (e.g. coral reefs) or their maintenance (e.g. grazing echinoderms). This focus overlooks direct and indirect effects of CO₂ on non-calcareous taxa that play critical roles in ecosystem shifts (e.g. competitors). We present the model that future atmospheric [CO₂] may act as a resource for mat-forming algae, a diverse and widespread group known to reduce the resilience of kelp forests and coral reefs. We test this hypothesis by combining laboratory and field CO₂ experiments and data from ‘natural’ volcanic CO₂ vents. We show that mats have enhanced productivity in experiments and more expansive covers in situ under projected near-future CO₂ conditions both in temperate and tropical conditions. The benefits of CO₂ are likely to vary among species of producers, potentially leading to shifts in species dominance in a high CO₂ world. We explore how ocean acidification combines with other environmental changes across a number of scales, and raise awareness of CO₂ as a resource whose change in availability could have wide-ranging community consequences beyond its direct effects.     

Skeletal isotope microprofiles of growth perturbations in<Emphasis Type="Italic"> Porites</Emphasis> corals during the 1997–1998 mass bleaching event

Severe coral bleaching occurred throughout the tropics in 1997/98. We report high-resolution skeletal oxygen isotope (¹⁸O) and carbon isotope (¹³C) microprofiles for bleached corals from Pandora Reef, Great Barrier Reef, and Ishigaki Island, Japan, in order to examine the ability of Porites corals to record clear signals of bleaching. Analysis of the annual cycle in ¹⁸O revealed abrupt reductions in skeletal extension immediately after the 1997–98 summer temperature maximum, indicating that bleaching inhibits coral calcification. Skeletal ¹³C in the Ishigaki corals showed lower values during bleaching, indicating depressed coral metabolism associated with a reduction in calcification. In contrast, microprofiles of skeletal ¹³C from the shaded sides of Pandora Reef corals exhibited little change, possibly because algal photosynthesis was already slow prior to bleaching, thus subduing the ¹³C-response to bleaching. Comparison of ¹⁸O microprofiles from bleached corals with instrumental temperature records showed that Porites corals can recover following 5 months with little skeletogenesis. The results indicate that isotopic microprofiling may be the key to identifying gaps in coral growth that are diagnostic of past bleaching events. We have tested this hypothesis using blue UV fluorescent bands to guide us to coral skeleton where isotope microprofiling identifies bleaching events in 1986, 1989, and 1990. These events, detected by proxy, suggest that coral bleaching may have occurred more commonly on Ishigaki Island than previously recorded.