Importance of methodological pluralism in deriving counterfactuals for evidence-based conservation

Most protected area impact research that uses counterfactuals draws heavily on quantitative methods, data, and knowledge types, making it valuable in producing generalizations but limited in temporal scope, historical detail, and habitat diversity and coverage of ecosystem services. We devised a methodological pluralistic approach, which supports social science qualitative methods, narratives, mixed methods, and interdisciplinarity, to fully unlock the potential of counterfactuals in ensuring a place-based and detailed understanding of the socioecological context and impacts of protected areas. We applied this approach to derive possible counterfactual conditions for the impact of a montane protected area on 40 years of vegetation change in the Cape Floristic Region-a global biodiversity hotspot and UNESCO World Heritage Site in South Africa. We incorporated diverse methods, knowledge, and information sources, drawing on before-after protected area comparisons for inside and outside the protected area. A significant increase in shrubland vegetation (17-30%) was observed and attributed primarily to a decline in frequent burning for grazing. This also occurred outside the protected area and was driven by socioeconomic drivers and not by concerns over biodiversity conservation or land degradation. Had the protected area not been established the area would have seen intensification of cultivation and increased road networks, buildings, and water storage in dams. Our approach increased historical temporal coverage of socioecological change and contextualized assumptions around causality. Protected area impact evaluation should reengage in place-based research that fully incorporates pluralism in methodologies for constructing counterfactuals in a way that builds regional and global understanding from the local level upward. We devised 10 key principles for deriving counterfactuals grounded in methodological pluralism, covering aspects of collaboration, cocreation, inter- and transdisciplinarity, diverse values and lived experiences, multiple knowledge types, multiple possible causal mechanisms, social science qualitative methods, perceptions, perspectives, and narratives.

Trees, carbon, and the psychology of landscapes

Mitigating climate change while safeguarding biodiversity and livelihoods is a major challenge. However, rampant afforestation threatens biodiversity and livelihoods, with questionable benefits to carbon storage. The narrative of landscape degradation is often applied without considering the history of the landscape. While some landscapes are undoubtedly deforested, others existed in open or mosaic states before human intervention, or have been deliberately maintained as such. In psychology, a 'fundamental attribution error' is made when characteristics are attributed without consideration of context or circumstances. We apply this concept to landscapes, and then propose a process that avoids attribution errors by testing a null hypothesis regarding past forest extent, using palaeoecology and other long-term data, alongside ecological and stakeholder knowledge.

Post-fire summer rainfall differentially affects reseeder and resprouter population recovery in fire-prone shrublands of South Africa

Summer rainfall can have strong effects on post-fire mediterranean-type shrubland recovery patterns, with potentially long-lasting implications on communities. Our three-year field rainfall manipulation experiment tested post-fire survival and physiological responses of reseeders and resprouters to contrasting summer rainfall patterns in Fynbos and Renosterveld shrublands in South Africa. Climate projections are uncertain for this region but indicate that increased convective summer rainfall events could occur. We irrigated treatment plots during the hottest summer months (i.e. Jan, Feb, March) to contrast the naturally dry summer conditions. This allowed for assessments of the potential limiting effects of summer drought on post-fire vegetation recovery and the responsiveness of vegetation to moisture inputs during this time. Natural summer droughts led to leaf dehydration, reduced photosynthesis and reduced photosynthetic capacity. This had a particularly severe effect on reseeders during the first summer after fire leading to high mortality rates. Summer irrigations strongly reduced levels of reseeder stress and mortality. Resprouters in both vegetation types were physiologically less sensitive to rainfall patterns and showed little drought-related mortality. Comparisons of final population sizes with emergence and survival patterns showed that summer rainfall during the first summer after fire had the potential to strongly alter reseeder population sizes. The physiological sensitivity of plants to summer rainfall patterns was higher in shrubland communities occurring on fine-textured, moderately fertile soils (e.g. Renosterveld). Shrublands occurring on sandy, nutrient-poor soils (e.g. Fynbos) were remarkably insensitive to summer drought after the first summer with lower irrigation responses. Our study demonstrated the potential for variation in post-fire summer rainfall to strongly affect reseeder and resprouter population recovery patterns.

Does a trade-off between growth plasticity and resource conservatism mediate post-fire shrubland responses to rainfall seasonality?

Growth plasticity may allow fire-prone species to maximize their recovery rates during temporary, sporadic periods of rainfall availability in the post-fire environment. However, moisture-driven growth plasticity could be maladaptive in nutrient-limited environments that require tighter control of growth and resource use. We investigated whether a trade-off between plasticity and conservatism mediates growth responses to altered rainfall seasonality in neighbouring shrubland communities that occupy different soils. We monitored post-fire vegetation regrowth in two structurally similar, Mediterranean-type shrublands for 3 years. We investigated the effects of experimentally altered rainfall seasonality on post-fire species' growth rates. We found that moisture-driven growth plasticity was higher among species occupying the fertile soils of the renosterveld site relative to those occupying the nutrient-poor soils of the fynbos site. This resulted in higher overall responsiveness of post-fire recovery patterns in renosterveld to experimental shifts in rainfall seasonality. In post-fire shrubland communities, the trade-off between moisture-dependent growth plasticity and resource conservatism could be mediated by soil nutrient availability. Therefore, edaphic differences between structurally similar shrublands could lead to differences in their sensitivity to post-fire rainfall seasonality.

Recent trends in the climate of Namaqualand, a megadiverse arid region of South Africa

Abstract Namaqualand is especially vulnerable to future climate change impacts. Using a high-resolution (0.5°x0.5°) gridded data set (CRU TS 3.1) and individual weather station data, we demonstrated that temperatures as well as frequency of hot extremes have increased across this region. Specifically, minimum temperatures have increased by 1.4 °C and maximum temperatures by 1.1 °C over the last century. Of the five weather stations analysed, two showed evidence of a significant increase in the duration of warm spells of up to 5 days per decade and a reduction in the number of cool days (TX10P) by up to 3 days per decade. In terms of rainfall, we found no clear evidence for a significant change in annual totals or the frequency or intensity of rainfall events. Seasonal trends in rainfall did, however, demonstrate some spatial variability across the region. Spatial trends in evapotranspiration obtained from the 8-day MOD16 ET product were characterised by a steepening inland-coastal gradient where areas along the coastline showed a significant increase in evapotranspiration of up to 30 mm per decade, most notably in spring and summer. The increase in temperature linked with the increases in evapotranspiration pose significant challenges for water availability in the region, but further research into changes in coastal fog is required in order for a more reliable assessment to be made. Overall, the results presented in this study provide evidence-based information for the management of climate change impacts as well as the development of appropriate adaptation responses at a local scale.

The Consequences of Precipitation Seasonality for Mediterranean-Ecosystem Vegetation of South Africa

Globally, mediterranean-climate ecosystem vegetation has converged on an evergreen, sclerophyllous and shrubby growth form. The particular aspects of mediterranean-climate regions that contribute to this convergence include summer droughts and relatively nutrient-poor soils. We hypothesised that winter-precipitation implies stressful summer droughts and leaches soils due to greater water availability (i.e. balance between precipitation and potential evapotranspiration; P-PET) during cold periods. We conducted a comparative analysis of normalised difference vegetation indices (NDVI) and edaphic and climate properties across the biomes of South Africa. NDVI was strongly correlated with both precipitation and P-PET (r2 = 0.8). There was no evidence, however, that winter-precipitation reduces NDVI in comparison to similar amounts of summer-precipitation. Base saturation (BS), a measure of soil leaching was, however, negatively related to P-PET (r2 = 0.64). This led to an interaction between P-PET and BS in determining NDVI, indicating the existence of a trade-off between water availability and soil nutrients that enables NDVI to increase with precipitation, despite negative consequences for soil nutrient availability. The mechanism of this trade-off is suggested to be that water increases nutrient accessibility. This implies that along with nutrient-depauperate geologies and long periods of time since glaciation, the winter-precipitation may have contributed to the highly leached status of the soils. Since many of the ecophysiological characteristics of mediterranean-ecosystem flora are associated with low nutrient availabilities (e.g. evergreen foliage, sclerophylly, cluster roots), we conclude that mediterranean-climates promote convergence of growth-forms in these regions through high leaching capacity.

The historical ecology of Namibian rangelands: vegetation change since 1876 in response to local and global drivers

The influence of both local and global drivers on long-term changes in the vegetation of Namibia's extensive rangelands was investigated. Fifty-two historical photographs of the Palgrave Expedition of 1876 were re-photographed and used to document changes over more than 130 years, in grass, shrub and tree cover within three major biomes along a 1200km climatic gradient in central and southern Namibia. We showed that patterns of change are correlated with mean annual precipitation (MAP) and that below a threshold of around 250mm, vegetation has remained remarkably stable regardless of land-use or tenure regime. Above this threshold, an increase in tree cover is linked to the rainfall gradient, the legacies of historical events in the late 19th century, subsequent transformations in land-use and increased atmospheric CO(2). We discuss these findings in relation to pastoral and settler societies, paleo- and historical climatic trends and predictions of vegetation change under future global warming scenarios. We argue that changes in land-use associated with colonialism (decimation of megaherbivores and wildlife browsers; fire suppression, cattle ranching), as well as the effects of CO(2) fertilisation provide the most parsimonious explanations for vegetation change. We found no evidence that aridification, as projected under future climate change scenarios, has started in the region. This study provided empirical evidence and theoretical insights into the relative importance of local and global drivers of change in the savanna environments of central and southern Namibia and global savanna ecosystems more generally.

Rivers through time: historical changes in the riparian vegetation of the semi-arid, winter rainfall region of South Africa in response to climate and land use

This paper examines how the riparian vegetation of perennial and ephemeral rivers systems in the semi-arid, winter rainfall region of South Africa has changed over time. Using an environmental history approach we assess the extent of change in plant cover at 32 sites using repeat photographs that cover a time span of 36-113 years. The results indicate that in the majority of sites there has been a significant increase in cover of riparian vegetation in both the channel beds and adjacent floodplain environments. The most important species to have increased in cover across the region is Acacia karroo. We interpret the findings in the context of historical changes in climate and land use practices. Damage to riparian vegetation caused by mega-herbivores probably ceased sometime during the early 19th century as did scouring events related to large floods that occurred at regular intervals from the 15th to early 20th centuries. Extensive cutting of riparian vegetation for charcoal and firewood has also declined over the last 150 years. Changes in the grazing history as well as increased abstraction and dam building along perennial rivers in the region also account for some of the changes observed in riparian vegetation during the second half of the 20th century. Predictions of climate change related to global warming anticipate increased drought events with the subsequent loss of species and habitats in the study area. The evidence presented here suggests that an awareness of the region's historical ecology should be considered more carefully in the modelling and formulation of future climate change predictions as well as in the understanding of climate change impacts over time frames of decades and centuries.

A fence line in time demonstrates grazing-induced vegetation shifts and dynamics in the semiarid Succulent Karoo

The mediterranean ecosystems of the world harbor exceptional biodiversity, and factors such as livestock grazing which may negatively affect biodiversity are of global concern. The mediterranean ecosystems of southern Africa have only sporadically been exposed to high densities of indigenous herbivores and may not be as typically resilient to livestock grazing pressure as the savannah and grassland ecosystems of semiarid Africa. We investigate this issue by assessing the impacts of two contrasting livestock grazing intensities associated with communal and commercial ranching systems on the dwarf succulent shrublands of the Succulent Karoo in Namaqualand, South Africa. We interpret the results in terms of vegetation dynamics and the implications for the current debate on nonequilibrium rangelands. The results demonstrate that the relative extent of plant community divergence between the communal and commercial rangeland has been maintained over the past 10 years, overall and within different plant growth forms. Recruitment of certain palatable shrub species occurred on the heavily grazed communal rangeland, indicating that a further decline in their populations is not inevitable. Recruitment of the unpalatable shrub Galenia africana on the communal rangeland was disproportionately greater than that of the palatable species, reenforcing the dominance of this species. Due to the longevity of woody shrubs, short-term vegetation shifts are small, limiting the potential for the recovery of overgrazed shrublands during periods of low grazing pressure. The shift on the communal rangeland toward annuals and geophytes has increased the variability of forage production and contrasts with the dominance of dwarf shrubs on the commercial rangeland. Shrub-dominated ecosystems create the potential for forage storage and inter-annual transfer of excess production, buffering livestock numbers in the face of a fluctuating environment. Despite the semiarid nature of the area and contrary to the predictions of the nonequilibrium theory, livestock and vegetation in Namaqualand interact strongly, and a close relationship between livestock numbers and primary production persists over the long-term on the communal rangeland.

Mapping grazing-induced degradation in a semi-arid environment: a rapid and cost effective approach for assessment and monitoring

Improved techniques for measuring and monitoring the state of biodiversity are required for reporting on national obligations to international and regional conservation institutions. Measuring the extent of grazing-related degradation in semi-arid ecosystems has proved difficult. Here we present an accurate and cost-effective method for doing this, and apply it in a South African semi-arid region that forms part of a globally significant biodiversity hotspot. We grouped structurally and functionally similar vegetation units, which were expert-mapped at the 1:50,000 scale, into four habitat types, and developed habitat-specific degradation models. We quantified degradation into three categories, using differences between dry and wet season values of the Normalized Difference Vegetation Index (NDVI) for the three succulent karoo habitats, and the difference between maximum and mean NDVI values for the subtropical thicket habitat. Field evaluation revealed an accuracy of 86%. Overall, degradation was high: 24% of the study area was modeled as severely degraded, and only 9% as intact. Levels of degradation were highest for bottomland habitats that were most exposed to grazing impacts. In sharp contrast to our methods, a widely used, broad-scale and snapshot assessment of land cover in South Africa was only 33% accurate, and it considerably underestimated the extent of severely degraded habitat in the study area. While our approach requires a multidisciplinary team, and in particular expert knowledge on the characteristics and spatial delimitation of vegetation types, it is repeatable, rapid, and relatively inexpensive. Consequently, it holds great promise for monitoring and evaluation programs in semi-arid ecosystems, in Africa, and beyond.

Once-a-day Concerta methylphenidate versus three-times-daily methylphenidate in laboratory and natural settings

OBJECTIVE

Methylphenidate (MPH), the most commonly prescribed drug for attention-deficit/hyperactivity disorder (ADHD), has a short half-life, which necessitates multiple daily doses. The need for multiple doses produces problems with medication administration during school and after-school hours, and therefore with compliance. Previous long-acting stimulants and preparations have shown effects equivalent to twice-daily dosing of MPH. This study tests the efficacy and duration of action, in natural and laboratory settings, of an extended-release MPH preparation designed to last 12 hours and therefore be equivalent to 3-times-daily dosing.

METHODS

Sixty-eight children with ADHD, 6 to 12 years old, participated in a within-subject, double-blind comparison of placebo, immediate-release (IR) MPH 3 times a day (tid), and Concerta, a once-daily MPH formulation. Three dosing levels of medication were used: 5 mg IR MPH tid/18 mg Concerta once a day (qd); 10 mg IR MPH tid/36 mg Concerta qd; and 15 mg IR MPH tid/54 mg Concerta qd. All children were currently medicated with MPH at enrollment, and each child's dose level was based on that child's MPH dosing before the study. The doses of Concerta were selected to be comparable to the daily doses of MPH that each child received. To achieve the ascending rate of MPH delivery determined by initial investigations to provide the necessary continuous coverage, Concerta doses were 20% higher on a daily basis than a comparable tid regimen of IR MPH. Children received each medication condition for 7 days. The investigation was conducted in the context of a background clinical behavioral intervention in both the natural environment and the laboratory setting. Parents received behavioral parent training and teachers were taught to establish a school-home daily report card (DRC). A DRC is a list of individual target behaviors that represent a child's most salient areas of impairment. Teachers set daily goals for each child's impairment targets, and parents provided rewards at home for goal attainment. Each weekday, teachers completed the DRC, and it was used as a dependent measure of individualized medication response. Teachers and parents also completed weekly standardized ratings of behavior and treatment effectiveness. To evaluate the time course of medication effects, children spent 12 hours in a laboratory setting on Saturdays and medication effects were measured using procedures and methods adapted from our summer treatment program. Measures of classroom behavior and academic productivity/accuracy were taken in a laboratory classroom setting during which children completed independent math and reading worksheets. Measures of social behavior were taken in structured, small-group board game settings and unstructured recess settings. Measures included behavior frequency counts, academic problems completed and accuracy, independent observations, teacher and counselor ratings, and individualized behavioral target goals. Reports of adverse events, sleep quality, and appetite were collected.

RESULTS

On virtually all measures in all settings, both drug conditions were significantly different from placebo, and the 2 drugs were not different from each other. In children's regular school settings, both medications improved behavior as measured by teacher ratings and individualized target behaviors (the DRC); these effects were seen into the evening as measured by parent ratings. In the laboratory setting, effects of Concerta were equivalent to tid MPH and lasted at least through 12 hours after dosing. Concerta was significantly superior to tid MPH on 2 parent rating scores, and when asked, more parents preferred Concerta than preferred tid IR MPH or placebo. Side effects on children's sleep and appetite were similar for the 2 preparations. In the lab setting, both medications improved productivity and accuracy on arithmetic seatwork assignments, disruptive and on-task behavior, and classroom rule following. Both medications improved children's rule following and negative behavior in small group board games, as well as in unstructured recess settings. Individual target behaviors also showed significant improvement with medication across domains in the laboratory setting. Children's behavior across settings deteriorated across the laboratory day, and the primary effect of medication was to prevent this deterioration as the day wore on. Results support the use of background behavioral treatment in clinical trials of stimulant medication, and illustrate the utility of a measure of individualized daily target goals (ie, the DRC) as an objective measure of medication response in both the laboratory and natural school settings.

CONCLUSION

This investigation clearly supports the efficacy of the Concerta long-acting formulation of MPH for parents who desire to have medication benefits for their child throughout the day and early evening. (ABSTRACT TRUNCATED)

Coronary artery stenting during acute myocardial infarction in patients treated with IIb/IIIa anti-platelet antibodies: early outcome results

Percutaneous transluminal coronary angioplasty has been shown to be an effective treatment for acute myocardial infarction. Despite encouraging results, this form of treatment is limited by a high incidence of recurrent ischemia either due to early rethrombosis or to restenosis of the infarct vessel within the first six months. Coronary artery stents decrease restenosis but are considered contraindicated in situations were thrombus is present. c7E3 is a potent anti-platelet agent which inhibits thrombus formation. We developed 44 stents as part of angioplasty for acute myocardial infarction in 18 patients given c7E3. All patients obtained normal flow angiographically and no stent thrombosis was observed.

Desertification of the eastern Karoo, South Africa: Conflicting paleoecological, historical, and soil isotopic evidence

The desertification debate in South Africa has benefitted greatly in recent years from the contributions of a wide range of disciplines. In this paper we review the conflicting and supporting evidence for degradation in the eastern Karoo as reported in recent archaeological, historical, and stable carbon isotope studies as it relates to three key aspects of the debate: the precolonial environment, the rate and nature of change, and the relative contributions of humans and climate to the process. First, all studies suggest a greater grassiness at some time in the past, but researchers disagree on the timing of the switch to more shrubby conditions in the eastern Karoo. Second, regional rainfall records for the past 2 decades reveal an above-average rainfall period, and numerous long-term surveys show an increase in grass cover over the same period. These findings question the expanding Karoo hypothesis as well as the argument that the Karoo's carrying capacity has decreased in recent years. Finally, the relative responsibilities of humans and climate in the degradation process remain poorly understood and generally have not formed the focus of investigation.