John P. Simaika

A comparative analysis reveals weak relationships between ecological factors and beta diversity of stream insect metacommunities at two spatial levels

The hypotheses that beta diversity should increase with decreasing latitude and increase with spatial extent of a region have rarely been tested based on a comparative analysis of multiple datasets, and no such study has focused on stream insects. We first assessed how well variability in beta diversity of stream insect metacommunities is predicted by insect group, latitude, spatial extent, altitudinal range, and dataset properties across multiple drainage basins throughout the world. Second, we assessed the relative roles of environmental and spatial factors in driving variation in assemblage composition within each drainage basin. Our analyses were based on a dataset of 95 stream insect metacommunities from 31 drainage basins distributed around the world. We used dissimilarity-based indices to quantify beta diversity for each metacommunity and, subsequently, regressed beta diversity on insect group, latitude, spatial extent, altitudinal range, and dataset properties (e.g., number of sites and percentage of presences). Within each metacommunity, we used a combination of spatial eigenfunction analyses and partial redundancy analysis to partition variation in assemblage structure into environmental, shared, spatial, and unexplained fractions. We found that dataset properties were more important predictors of beta diversity than ecological and geographical factors across multiple drainage basins. In the within-basin analyses, environmental and spatial variables were generally poor predictors of variation in assemblage composition. Our results revealed deviation from general biodiversity patterns because beta diversity did not show the expected decreasing trend with latitude. Our results also call for reconsideration of just how predictable stream assemblages are along ecological gradients, with implications for environmental assessment and conservation decisions. Our findings may also be applicable to other dynamic systems where predictability is low.

An easy-to-use index of ecological integrity for prioritizing freshwater sites and for assessing habitat quality

Prioritizing and assessing the condition of sites for conservation action requires robust and ergonomic methodological tools. We focus here on prioritizing freshwater sites using two promising biodiversity indices, the Dragonfly Biotic Index (DBI) and Average Taxonomic Distinctness (AvTD). The AvTD had no significant association with either species richness or endemism. In contrast, the DBI was highly significantly associated with species richness and endemism, although the strengths of the associations were weak. These associations are related to how the sub-indices in the DBI are weighted, and how species are distributed geographically. Additionally, the DBI was found to be very useful for site selection based on its ability to measure ecological integrity, combined with level of threat, at multiple spatial scales. The AvTD was found to be useful principally for regional use. As the DBI is a low-cost, easy-to-use method, it has the additional use as a method for assessing habitat quality and recovery in restoration programs. The DBI operates at the species level, and is therefore highly sensitive to habitat condition and has great potential for environmental assessment and monitoring freshwater biodiversity and quality. Practical, worked examples of river restoration are given here. In view of the ease and versatility by which the DBI can be employed, we recommend its testing and possible integration into freshwater management and conservation schemes elsewhere in the world.

Biophilia as a Universal Ethic for Conserving Biodiversity

Biophilia, meaning “love of life or living systems” (Fromm 1964), refers to the psychological tendency in humans to be attracted to all that is alive and vital. Popularized in Wilson’s (Wilson 1984) Biophilia, the term’s meaning changed to “an innate love for nature,” which suggests biophilia is genetically inherited, albeit “weakly” so (Kellert 2009). In the subsequent The Biophilia Hypothesis (Kellert & Wilson 1993), several contributors examine the validity of Wilson’s biophilia hypothesis, with Wilson (1993) proposing that biophilia evolved by natural selection in a cultural context, a process to which he refers as gene-culture co-evolution (Gullone 2000b). Evidence for biophilia as envisioned by Wilson is scant or circumstantial and cannot be tested easily. Since its conception, the term biophilia has only rarely been used in peer-reviewed articles; some authors use and accept Wilson’s meaning (e.g., Mart́ınez-López et al. 2007), whereas others prefer to use Fromm’s original definition (e.g., Van den Born 2001), which lacks any statement on the heritability of biophilia.

Effect of alien riparian vegetation and its removal on a highly endemic river macroinvertebrate community

Invasive alien trees along river banks can reduce indigenous biodiversity, while their removal can restore it. We assessed here family- and species-level responses of river benthic macroinvertebrate assemblages to three riparian vegetation types (natural, alien trees, cleared of alien trees) in the Cape Floristic Region biodiversity hotspot. High species beta diversity of this highly endemic fauna meant that between-river, as well as seasonal effects, dominated assemblage patterns. SASS5, a qualitative, rapid bioassessment technique, based on the sensitivity of the families present, was used as a measure of river health and, indirectly, of water quality. SASS indicated a decline in water quality conditions after alien clearing, a likely response to the greater insolation and apparent erosion of cleared banks, resulting in elevated temperatures and suspended solids and lowered oxygen levels. Overall, cleared and natural sites were more similar to each other than to alien sites, suggesting some post-clearing recovery. However, many sensitive, endemic taxa survived in alien-invaded sites, and more than in the natural sites. These endemic species made use of shady, cool, high-oxygen levels under the alien tree canopy. However, endemics declined in overall abundance in sites cleared of aliens, being replaced by more tolerant, widespread taxa. Clearance of the alien trees opened up the rivers to sunny conditions, which had a major impact on community composition. Vegetation types, oxygen levels and river width were important environmental variables affecting these macroinvertebrate responses. Re-establishment of invertebrate biodiversity matched that of indigenous vegetation, with the most sensitive endemic taxa only recovering after establishment of bushy indigenous and shade-producing fynbos. Therefore, for biodiversity conservation objectives to be achieved, it is essential that indigenous plants are maintained and encouraged during and after clearing to ensure the recovery of endemic and sensitive taxa.

Artificial ponds increase local dragonfly diversity in a global biodiversity hotspot

Human demands have led to an increased number of artificial ponds for irrigation of crops year-round. Certain insect species have established in these ponds, including dragonflies (Insecta: Odonata). There has been discussion around the value of artificial ponds for encouraging dragonfly diversity, with little work in biodiversity hotspots rich in rare and endemic species. We focus here on the Cape Floristic Region (CFR) global biodiversity hotspot, which has many endemic dragonfly species but has few natural ponds. Yet it has many artificial ponds mostly used for irrigation on local farms. This leads to an interesting question: to what extent do these artificial ponds provide habitats for dragonflies in this biologically rich, agriculturally fragmented landscape? To answer this, we recorded dragonfly species richness and abundances from 17 artificial ponds and 13 natural stream deposition pools as reference, in an area of the CFR where there are no local, natural, perennial ponds. Thirteen environmental and physical variables were recorded at the ponds and pools. We found that although ponds attracted no rare or threatened dragonfly species, they increased the area of occupancy and population sizes of many generalist species. These came from nearby natural deposition pools or from unknown sources elsewhere in the region, so providing refuges which otherwise would not be there. Interestingly, some CFR endemic species were also recorded at our artificial ponds. Overall dragonfly assemblages and those of true dragonflies (Anisoptera) and damselflies (Zygoptera) differed between artificial ponds and deposition pools, suggesting that artificial ponds are to some extent a novel ecosystem. Habitat type, elevation and temperature were significant drivers in structuring overall species assemblages. For the Anisoptera, riparian vegetation and level of landscape connectivity was important, while temperature was not. In contrast, Zygoptera species were most affected by river catchment, habitat type and temperature. In sum, these artificial ponds are stepping stone habitats across an increasingly fragmented landscape. Managing these ponds with perennial water, constant water levels, and maximum complexity and heterogeneity of habitats in terms of vegetation will conserve a wide range of generalists and some specialists.

Predicted range shifts of dragonflies over a wide elevation gradient in the southern hemisphere

Human-induced climate change is among the greatest threats to biodiversity, especially when coupled with habitat destruction. For an already water-stressed country like South Africa, changes in temperature and precipitation regimes, coupled with increasing water demands, are likely to lead to losses in biodiversity. Dragonflies are a well-studied surrogate taxon for aspects of freshwater biodiversity. We created species distribution models for 14 dragonfly species, and predicted the changes in species richness, extent of occurrence, and habitat suitability for the years 2050 and 2080 in South Africa, a poorly studied area for range-change predictions for insects. Model predictions for 2 different emissions scenarios suggest that at least 2 species will be lost from the area by 2050, and 3 by 2080. All are widespread Afrotropical species, but with narrow elevation ranges in South Africa. Only 1 species is predicted to benefit greatly from climate change. The remaining species are predicted to persist with reduced extents of occurrences at higher elevations. Most species we studied (12 of 14) thrive in artificial environments. Therefore, to a certain extent, loss in connectivity is unlikely to play a role for these species. However, the 2 stream specialists that occur in the area are particularly vulnerable because of loss of habitat. Species that currently occur farther north in southern Africa and South Africa also are likely to move southward in the future. Thus, species richness may not necessarily decrease, but replacement of species within communities will be significant.

Pollinator conservation at the local scale: flower density, diversity and community structure increase flower visiting insect activity to mixed floral stands

Insect pollinators play a keystone role in terrestrial ecosystems. The parallel declines in plant and pollinator communities emphasizes that plant-pollinator interactions at the community level are highly relevant for biodiversity conservation. Here we examine relationships between plants and flower-visiting insects (anthophiles) at the scale of local floral patches. We conducted a visitation survey during the spring flowering season, a peak time for pollinator activity in the threatened Cape Floristic Region, South Africa. We tested floral density, diversity and composition as predictors of anthophile diversity (measured at the family/family group level) and visitation rates in multispecies stands of flowers. Although different anthophile groups responded differently, generally anthophile visitation rates and diversity were positively affected by floral density, diversity and community structure. Anthophiles were more abundant and diverse in areas with a high density and diversity of flowers. Plant community structure affected both the likelihood of occurrence and activity of anthophiles in the plots. The two mass flowering species examined here, Relhania fruticosa and Salvia chamaeleagnea, were strong determinants of anthophile activity, greatly increasing visitation rates, even though there was, on average, lower floral density and diversity. Our results show that anthophile activity is affected by highly localised, small-scale factors, namely the density and diversity of flowers and community structure. Important among these factors are patches of high quality habitat, high in floral abundance and diversity, both of which should be included in landscape-level plans for pollinator conservation, providing stepping stones for these insects in transformed landscapes.

Directions in dragonfly applied ecology and conservation science

Department of Integrative Biology, Oklahoma State University, Stillwater, Oklahoma 74078 USA School of Biology, University of Leeds, Leeds LS2 9JT UK Department of Conservation Ecology and Entomology, Faculty of AgriScience, Stellenbosch University, Private Bag X1 Matieland 7602, South Africa New York Natural Heritage Program, State University of New York College of Environmental Science and Forestry, Albany, New York 12233 USA Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102 USA

Dragonflies as Flagships for Sustainable Use of Water Resources in Environmental Education.

ABSTRACT Sustainable use of freshwater is globally important. Yet implementation of changes in water management is poor, especially in developing countries. This is an indication that, despite our dependence on freshwater, we lack awareness of the need to protect these systems. Here we promote dragonflies as an easy-to-learn tool in environmental education programs. Dragonflies have been employed successfully as indicators of ecosystem health in environmental impact assessments and monitoring programs globally. They can be used as environmental sentinels and as whistleblowers for freshwater health, providing an effective tool for environmental impact assessments and freshwater monitoring. We give detailed examples here of some successful projects from South Africa, Tanzania, and Japan. The approaches developed are models that pave the way for more water awareness projects elsewhere, especially in developing countries, where biodiversity and pressures on freshwater systems are high.

Correction to: Insect conservation psychology

The article Insect conservation psychology, written by John P. Simaika, Michael J. Samways was originally published electronically on the publisher’s internet portal (currently SpringerLink) on 21 February 2018 without open access.