The Role Of Biogeography In Informing Conservation Practice And Policy

The International Union for Conservation of Nature (IUCN) was founded in 1948 as the first environmental union to promote conservation practice and policy (IUCN, 2018). The biogeographical concept of extinction has shown that the change of species on the evolutionary timeline is a natural process, described by a “natural background” rate of extinction. With measures of the status of the natural world by the IUCN, an accelerated extinction rate of 1. 000 – 10. 000 times is currently estimated, due to anthropogenic activity (Greenwald, n. d. ). To fight the current sixth mass extinction, with effective conservation management, biogeography is a critical tool in understanding the dynamics of all organisms. This essay will discuss the role of biogeography in conservation measures, with focus on insects. This will be further elaborated with the use of three case studies on the: rapid decline of insects in Germany, a conservation success story of the Large Blue butterfly in the UK and lastly the effects of urbanization on insect persistence in Rome. It is no secret that insects are highly important for the functioning of the global ecosystem, yet many entomologists see this research field as a vulnerable discipline, which has been neglected in the past.

Currently, some one million insect species are recorded, with invertebrates accounting for 97% of total animal species on Earth (Greenwald, n. d. ). Furthermore, they have occupied all earth’s biomes, with different degrees in respective climatic zones, but overall creating the greatest biodiversity of all species (Loxdale, 2016). They are identified to fulfil vital roles in the global ecosystem functioning through pollination, herbivory, nutrient cycling, food sourcing and many more. This makes most ecosystems highly dependent on these species (Hallmann et al. , 2017). A study undertaken by the Entomological Society Krefeld published new findings on the insect decline in Germany. The investigation of aerial biomass was conducted across 63 low-altitude nature protection sites, between 1989 and 2016. With the use of Malaise traps, the decline of localised insect biomass was examined against environmental parameters of habitat, weather and land use variables (ibid. ).

A decline of 76% of airborne insect biomass was recorded over the 27 year-period. This dramatic result surpasses by far the estimation of a 58% decline in global abundance of wild vertebrates over a 42-year period (ibid. ), placing even more weight on this urgent matter. The limitation of studied disturbance factors, paired with the lack of historical data on local insect biomass did not give a clear answer of the extinction drivers (Stager, 2018). Samways (2015) identifies 7 challenges which have restricted conservationists’ awareness for insect diversity in the past. Firstly, the perception challenge describes how attributes such as dangerous, fearful and parasitic have been associated with invertebrates, particularly insects, for too long and therefore build walls, ‘putting humans off’ these species. This is closely tied to the public dilemma, which outlines the lack of appreciation for ecosystem services which insects serve. This furthermore implies a lack of understanding how humans are dependent on these species for our own survival. As an example, wild pollinator taxa, such as the honeybee, deliver important services for food pollination (ibid. ).

According to the Pollination Assessment (IPBES, 2016), more than a third quarter of the world’s food rely in part on pollination. And while assessments on locally threatened invertebrate species have found that 40% of such are threatened to extinction, a global, regional or national assessment of threatened invertebrates has not yet been done. It has however been done for vertebrate pollinators (Lumpur, 2016). This underlines the argument of the forgotten importance of invertebrates for ecosystem services, which humans heavily rely on. The political dilemma describes the lack of political interest for invertebrate conservation, which results in relatively low public engagement. And without public engagement, political support for conservation funding, interest and support will also be limited. Therefore, these dilemmas support each other (Samways, 2015). Luckily, there has been a positive mainstream movement globally for conservation pollinator projects asking for their conservation, especially for honeybees (Friends of the Earth, Greenpeace, Pesticide Action Network Europe,…). According to Samways (2015), several shortfalls add to the previous problems underlying the neglected “future-proofing of insect diversity”. The Linnean shortfall gives attention to how many insect species are still not described, nor included in taxonomy. While one million species are acknowledged currently, an estimation of five million insect species are yet to be described. The Wallacean Shortfall outlines the lack of knowledge of distribution of described species.

Missing knowledge on insect abundance and their changes are termed under the Prestonian shortfall. The Hutchinson shortfall describes the unnoticed biological attributes of insect species, including niches and ecological tolerances (ibid. ). Together, these seven challenges build the makeup of the complex issues why and how insect conservation has been neglected. Terry Erwin elaborates on these issues stating that conservation has focused for too long on “cute and cuddlies” species (i. e. vertebrates) but has forgotten the bulk of the world’s animal species – the invertebrates (Mikanowski, 2017). Research is biased by focusing on certain phylogenetic and geographical distributions, yet the fundamentals for conserving policy is the knowledge of numbers, distribution and disturbance drivers of species (Dolphin and Quickie, 2001). If this preconditional biogeographical knowledge of insect species is missing, conservationists cannot possibly implement policies. The case study of the Large Blue butterfly (Maculinea arion) is a true testimony of how biogeographical knowledge of a species enables successful conservation management. The species was first documented in the 1790s in Britain by William Lewin. The biogeographical analysis of the species led to astonishing discoveries and was quickly recognised as an enigmatic species due its rarity and beauty (CEH, n. d. ). Sadly however, a declining trend of the species was visible, which was closely documented. In 1950, only 25 sites in Britain were occupied by the Large Blue and in 1972 only two sites before it came finally extirpated from Britain in 1979 (ibid. ).

After successful hatching, the larva feeds on the flowers of its host during the instars development phase. Once dropped on the floor after its moulting phase, the organism has to be picked up by a red ant (Myrmica sabuleti) and be taken back to the ant’s nest. There, the larva will feed on ant grubs for about 10 months before it will pupate into a butterfly. The flying period of a single organisms is restricted to 3 to 5 days and to a local habitat patch (ibid. ). The study of this species highlighted a lot of biogeographical concepts important for conservation policies. One of the most important findings was that only in the nests of Myrmica sabuleti, the caterpillar could survive, as the Large Blue had adapted a camouflage to not be deceived as an imposter when in the ant’s nest. Other red ants had adapted to this and were able to recognise this behaviour and kill the impostor (CEH, n. d. ). While the species inhibits many different niches across Europe, each population is highly specialised to its local habitat, its hosts and climatic factors. This makes the species most vulnerable to disturbances as their survival depends on the persistence of their hosts (Dolphin and Quickie, 2001). After their re-introduction in 1984, the species has successfully occupied 33 locations in south-west England, as seen in Fig. 1. The population growth was achieved by an extremely well-managed conservation programme. Conservations measurements include yet are not limited to: prevention of agricultural intensification, scrub and tree removal, maintenance of grassland while controlling vegetation succession and extensive livestock grazing (CEH, n. d. ).

Furthermore, the species is protected under the EU habitats directive, listed in Annex IV, which has promoted a conservation policy across Europe (EC, 2009). Figure 2 shows the Maculinea arion presence across Europe, after its re-introduction. [image: ]Fig. 2: Maculinea arion presence after its reintroduction, in latitudinal zones of c 40° and 62°N – inhibiting many niches across Europe (EC, 2009)This case study highlights how the biogeographical knowledge of the species helped with conservation management, based on the species’ ecological niche and tolerances. Looking at case study from Germany, the lack of historical data on local biomass weakens the possibility of putting effective conservation measures into place. Fundamental knowledge of dispersal, population numbers, and disturbance factors is limited and therefore these factors cannot be directly addressed. Including Samways’ seven challenges prohibiting the “future-proofing” of insect diversity (2015), biogeographical knowledge is not only important for conservation programmes, but also the precondition for noticing species’ extinction. Only by recognising the decline of the Large Blue butterfly, intensive research and conservation measures could be put into action. This is not only important for intrinsic values, but also supports the Gaia hypothesis, introduced by Lovelock in 1979. While controversial, it states that globally the ecosphere is in balance (Huggett, 2004). Through natural processes of speciation, diversity, dispersal and extinction, a natural equilibrium is maintained. Insects have existed since the Devonian Period, some 400 million years ago, and are experts in evolution (Loxdale, 2016). Considering that humans have had a much shorter evolutionary history yet are the driving factors for the ecological crisis of the mass extinction, a natural motivation to conserve these complex organisms should exist.

Whittaker et al. (2005) promote the idea of conservation biogeography. This assessment incorporates principles of biogeography and of the nature conservation movement. It carries a moral responsibility to re-define the human-nature relationship and persevere threatened life forms. Moreover, the ecosystem services delivered by insects are vital to the functioning of the ecosphere and to humans. In the UK alone, one-third of crop pollination is performed by native bumblebees adding £440 million a year to the economy (Goulson, 2012). At the same time, six native species are considered to be endangered, and three locally extinct. This global issue has affected some parts of the world so badly, that some farmers in south west China have had to hand-pollinate their crops due to local bee-extinction (ibid. ). With current predictions on the increasing extinction rate, conservation programmes must focus on these dynamic processes while understanding every-day patterns of diversity. This will enable to support biogeographical classification and setting objective conservation priority to different taxa. This will also intensive the small-scale biogeographical knowledge. The Large Blue butterfly case study showed that small, focused conservation programmes work effectively whilst studies on the whole class such as in the German case study can give a good overlook yet do not achieve the same success in managing insect decline. A long-term study from 1885 to 1999 analysed the effects of urbanisation on local insect presence in Rome. One observation was the increasing fragmentation of urban green spaces from semi-natural ecosystems outside the city. This limited the food sourcing for species, particularly for those with low dispersal abilities. The “increased density of insect-eating bird populations” (Fattorini, 2011,p. 374) was another disturbance factor. Urban Rome hosted a number of raptor species, for example the kestrel.

One of its main food sources is the darkling beetle – one of the declining insect species analysed in the study. While further disturbance factors such as biotope alterations and pollution were mentioned, Fattorini (2011) highlights that disturbances are experienced differently by each species and individuals, according to its ecology. This promotes inter- and intraspecific competition. These notions create a dramatic problem. Considering all three case studies, spatially-small studies focused on one species seem to succeed far better in their conservation targets as species can be directly addressed. The overall biogeographical knowledge of each species’ tolerance range is vital, and a precondition for management. However, the studies encompassing several species at once (Fattorini, 2011; Hallmann et al. ,2017) show the importance to not forget the large-scale issue of insect decline. With the current speed of extinction, the management focus of one by one species will not be attainable in the long-run. Biogeographical studies enable to set conservation priorities and understand disturbance factors better. What is a threat to some might be an opportunity to other species – a crucial biogeographical concept needing to be understood in order to address disturbance factors correctly (Samways, 2015).

Only with this knowledge will the most essential organisms for human survival, i. e. insects, have a chance to be conserved (Richardson and Whittaker, 2010). This is essential, and can be either due to human’s moral responsibility on re-arranging nature’s equilibrium or solely focusing on sustaining habitable environments for humans. And not to forget, that humans and insects are in direct competition. As veterinary pests, mosquitos cause million humans’ deaths in Africa annually by spreading Malaria. Additionally, insects can devastate crops, transmit pathogenic viruses, fungal diseases and many more (Loxdale, 2016). An increase in biogeographical knowledge of these species will help with those struggles as well. To conclude, biogeography is an important tool for the success of conservation policy.

As the Large Blue butterfly case study has shown, sufficient knowledge of a species’ ecological tolerances and niche is vital in conserving a species effectively. While a historical lack of interest in insects has been noted by several authors and case studies here, a paradigm shift is essential to preserve these species for several reasons. Not only do they have an intrinsic value, but humans also heavily rely on them for the important ecosystem services they serve. While a positive movement of insect-conservation programmes has recently arisen, for example for honeybees, conservation prioritising has yet to be installed. This is important in the race of humans running against extinction and to ensure that key-species are preserved, as the species-focus approach is not attainable with the current insect declining rate.

Therefore, the scale of studies and conservation management is extremely crucial in addressing different targets. Biogeographical knowledge on species numbers, -dispersal, -adaptation, -diversity and disturbance factors will help in placing these conservation priorities. Samways (2015) promotes the idea that the knowledge of insect biodiversity is the precondition for their conservation. This is supported by the German case study, where only speculations on disturbance factors could be made due to historical lack on local insect biomass. Additionally, the author of the case study in Rome raised the notion in carefully considering how some factors cause a threat to some species/individuals yet pose opportunities for others. Only with biogeographical knowledge, a balance can be thrived towards, and hopefully achieve further conservation success stories like the one of the Large Blue Butterfly.