Tag Archives: conservation

Cuban Red List

It had escaped my attention, but already in 2016 a Red List of terrestrial invertebrates for Cuba was published. It deals with Mollusca, Insecta and Arachnida.

Schermafbeelding 2020-05-28 om 13.25.10

The chapter on molluscs contains species of Cerionidae, Annulariidae, Cepolidae, Helicinidae, Urocoptidae, Orthalicidae, and Pleurodontidae. In total 88 (sub)species are listed and assessed according to the IUCN criteria. This < 10% of the species known from the island.

Schermafbeelding 2020-05-28 om 12.51.53

A very useful source of information and a good basis for further research.

Hidalgo-Gato González, M.M. et al., 2016. Libro Rojo de invetrebrados terrestres de Cuba. – Editorial Academia, La Habana, 241 pp. Link

Internet trade and conservation

In the just published number of Tentacle, one of the interesting articles is about shell trade via the internet. It is to be applauded that Chinese authors have taken this hot topic to the open as shell trade is definitely a threat to molluscan diversity. The normal reaction from traders will be that they trade shells they found empty, but this has in most cases to be considered incorrect (as the perfect state of shells on offer tells otherwise). Unfortunately, even professional malacologists fall sometimes for the temptation of describing new species from material collected by traders, thereby reinforcing this questionable practice of dealers and their collectors.

Schermafbeelding 2020-04-01 om 13.35.27

As the article shows a picture of Neotropical shells taken from a nature reserve in Florida, this is clearly a practice not limited to eastern Asia.

Zhang, G. & Wu, M., 2020. Internet trade, a new threat to malacodiversity. – Tentacle, 28: 12-14.

Land cover change in NE Mexico

Land-cover change and protected nature areas is not a subject that is well-studied. Vázquez-Reyes et al. recently published about it related to a region in northeastern Mexico.

Protected areas (PAs), priority terrestrial regions (PTRs) and priority terrestrial sites (PTSs) are strategies for conserving natural resources. However, loss of coverage on the peripheries can lead to isolation between these conservation areas. The present study analyzed the association of the change of coverage inside and outside 2 PAs, 5 PTRs and 128 PTSs in Tamaulipas with the richness and geographic distribution of 5 species groups (strict, semi-aquatic and tolerant hydrophiles, as well as gastropods and pteridophytes in 3 periods (1986, 2002 and 2011). In addition, we identified areas with similar species composition and socioeconomic-environmental factors related to the change in coverage. The highest richness and geographic distribution of aquatic plants occurred outside the conservation areas, while the greatest richness of ferns and gastropods was present inside them. The greatest loss of coverage occurred outside the El Cielo Biosphere Reserve and the Sierra de Tamaulipas PA. The loss of native cover increased in the last 30 years and is greater outside the conservation areas, therefore is necessary to propose and implement strategies to reduce the isolation of these areas“.

Schermafbeelding 2020-03-06 om 16.16.32

Although no list is given of the gastropods studied, assumingly they were terrestrial species. This is a policy study rather than a taxonomical one, but for conservation purposes it may be of interest.

Vázquez-Reyes, C.J. et al., 2019. Biodiversity risk from land-cover change in terrestrial priority regions and protected natural areas in northeastern Mexico. – Revista Mexicana de Biodiversidad 90: e902726 (16 pp.).

Demography Tikoconus

Due to oversight I missed the recent paper by Barrientos on the biology one of the new euconulid species; time to report it now.

Introduction: Ecology and natural history of neotropical land snails is almost unknown. Objetive: In this paper, I analyse the population dynamics of Tikoconus (Tikoconus) costaricanus Barrientos, an understory endemic euconulid.
Methods: I compared T. costaricanus’ demography patterns in tropical montane forests in central Costa Rica in three habitats with different restoration techniques: a mature forest, a secondary forest and a Cuppressus lusitanica plantation. I collected data in three month periods during a year. I analysed population size in relation with habitat, sampling date, leaf litter humidity, depth and quantity; and specimen size in relation with habitat and sampling date. I also kept some specimens in terraria and described part of their natural history.
Results: The species is more abundant in mature forest (Ø = 0.174 ind/m2). The number of specimens in each habitat was constant throughout the year (Kruskall-Wallis = 2.0118, p = 0.57, NS) and hatching occurs in the middle and last months of the rainy season (Kruskall-Wallis = 17.3061, P = 0.00061, **). Number of specimens is related with leaf litter humidity (Spearman correlation, r = 0.3524, n = 232, P < 0.001, **), quantity (Spearman correlation, r = 0.3922, n = 232, P < 0.001, **) and depth (Spearman correlation, r = 0.2543, n = 232, P < 0.001, **). This relationship is explained by the high and stable humid environment provided by leaf litter. Some specimens migrate from foliage to leaf litter during the drier months. Eggs (Ø = 1mm) are laid on moss or soil and the young spend the first 2 or 3 weeks of their life on moss. Egg masses are small (Ø = 4 eggs), and shells look bubbly. Egg development time (20 days) was longer than in other tropical species. Adult pigmentation appears around two months after hatch. In the only case observed, egg laying began 5 months after hatching and the specimen lived 9 months.
Conclusions: Restorations techniques should consider leaf litter features in order to protect endemic neotropical humid dependent diversity

Schermafbeelding 2020-02-15 om 08.48.27

This is an excellent ecological study of one of the new species recently described by her. And although the resulting data are not completely unexpected given the (very scarce) literature data, this study may have wider application than just the Costa Rican case. Albeit these studies are difficult to execute (especially if species are small and not occurring in abundant numbers), I hope that more Neotropical malacologists with endeavour them during field work.

Barrientos, Z., 2019. Demography of the land snail Tikoconus (Tikoconus) costaricanus (Stylommatophora: Euconulidae) in tropical low montane and premontane forests, Costa Rica. – Revista de Biología Tropical, 67(6): 1449-1460.

A rare Guadeloupe species

In the flush of the ‘end-of-the-year’ papers, a brief note was published by Lenoble & Charles on a rare species from Guadeloupe. Their abstract is “A shell of Laevaricella guadeloupensis (L. Pfeiffer, 1856) (Gastropoda, Oleacinidae) was found on Mahault Ridge, within the Guadeloupe National Park. This locality is the second where this endemic species to Basse-Terre has been identified since it was listed as extinct by IUCN in 1996“.

Schermafbeelding 2020-01-07 om 10.23.29

Besides an interesting record, it shows that one should be careful to list species as extinct, but at the same time it is clear that this specific species is extremely vulnerable.

Lenoble, A. & Charles, L., 2019. Nouvelle station de Laevaricella guadeloupensis (L. Pfeiffer, 1856), une espèce endémique rare de Guadeloupe (Mollusca, Gastropoda). – MalaCo, 15: 11-13.

Non-native South American species

An extensive analysis just appeared from Darrigan et al. (advance online) about the occurrence of non-native molluscs throughout South America. Their abstract is “Non-native species have been introduced at escalating rates during the last decades, mainly due to the dispersion generated by the increasing trade and transport worldwide. Mollusks, the second largest metazoan phylum in terms of species richness, are no exception to this pattern, but, to date, a comprehensive synthesis of non-native mollusk species (NNMS) in South America was not available. For this purpose, an e-discussion group was formed with malacologists and taxonomists from South America, where we exchanged and analyzed bibliography, databases and information about NNMS, providing expert opinion to this assessment. The first list of non-native mollusk species for South America, considering terrestrial, freshwater and marine environments, includes 86 NNMS distributed in 152 ecoregions (terrestrial, freshwater and marine) of the 189 recognized for the South American continent. Information on their native region, vectors, first record for South America and distribution, are also provided. In the analysis of the distribution of the NNMS and the entry points of each species (e.g., ports, cargo and passenger airports, cities) and status of conservation of the ecoregions, four hot spots were recognized: Subtropical-Atlantic, Northern Andes, Central Andes and Southern Andes. This work, thus, sets the baseline on NNMS for South America, a key piece of information regarding the development of policies targeting the management of biological invasions and their socio-ecological impacts“.

Schermafbeelding 2020-01-06 om 12.25.41

An interesting study that was totally done by South American malacologists. The paper contains a number of graphs and figures that illustrates the rapid increase over the past decades of non-native species in this understudied continent. It will be a good basis for further studies.

Darrigan, G. et al., 2020. Non-native mollusks throughout South America: emergent patterns in an understudied continent. – Biological Invasions (advance online): 19 pp. https://doi.org/10.1007/s10530-019-02178-4.

Priority conservation areas

A few years ago a species catalogue was published for Argentina (Superfamily Orthaicoidea only), which now forms the basis for a paper on conservation by Ovando et al.

Schermafbeelding 2019-08-02 om 08.16.37
Their abstract reads “Mollusca is a megadiverse phylum with an estimated number of 70,000–76,000 described species which can inhabit a wide variety of environments. Among them, land snails are a main component of terrestrial ecosystems and they play a pivotal role in ecosystem functioning. They are suffering habitat loss, overexploitation and competition from introduced species, but are regarded as a “non-charismatic” group for conservation purposes. Orthalicoidea is a dominant faunal element in the Neotropics and in Argentina includes 104 species that inhabit a variety of environments. Their abundance, diversity, comprehensive taxonomy and widespread representation in different ecoregions makes this molluscan group an excellent model for biodiversity assessments. The database used here consisted of 985 unique geographic records of 104 species. Species distribution models were generated using the Maximum Entropy method and Zonation v 3.1 was used to evaluate the proposed conservation goals. Three analyses including species distributions, the current protected areas system (PAs) and the Human print layer were carried out. This allowed the identification of priority areas for conservation, the percentage of the species distribution under PAs and analysis of the potential impacts under current land use and in the priority areas detected above. Sixty-one species were modeled, and 59 of them were included in the priority area selection process due to their high area under curve (AUC) scores. Five high priority areas located in the different ecoregions, were identified: 1-dry Chaco, 2-humid Pampas, 3-Southern Andean Yungas, 4-Alto Paraná Atlantic Forests and 5-high Monte. A small percentage of the average distribution range of Orthalicoidean species (3%) was within the current protected areas. Highest-ranked priority areas for land snails are outside the current protected areas system. When human impact is considered, the priority areas are reduced in size and appear as small patches. However, highest priority areas for conservation continue being those detected in the above analyses. Most of the areas detected are used for economic purposes, creating conflicts of interest between the development of human activities and conservation. This study represents one of the first attempts to identify ecoregion level priority areas for a terrestrial invertebrate group. Further analyses, including new predictors and other molluscan taxa, would improve planning the conservation of poorly known invertebrate groups“.

Schermafbeelding 2019-08-02 om 08.18.17

A useful study, the more as the authors have embraced the ecosystems approach widely used in conservation policies, and with interesting results concerning this group. Their conclusions that conflicts of interests between economic development and conservation continue is nor new nor re-assuring. We all know that conservation is likely to draw the shortest straw in this battle…

Ovando, X.M.C. et al., 2019. Identifying priority areas for invertebrate conservation using land snails as models> Journal for Nature Conservation 50: 125707 (10 pp.).