Threatened Neotropical seasonally dry tropical forest: evidence of biodiversity loss in sap-sucking herbivores over 75 years

Abstract

Tropical forests cover 7% of the earth's surface and hold 50% of known terrestrial arthropod species. Alarming insect declines resulting from human activities have recently been documented in temperate and tropical ecosystems worldwide, but reliable data from tropical forests remain sparse. The sap-sucking tribe Athysanini is one herbivore group sensitive to anthropogenic perturbation and the largest within the diverse insect family Cicadellidae distributed in America's tropical forests. To measure the possible effects of deforestation and related activities on leafhopper biodiversity, a survey of 143 historic collecting localities was conducted to determine whether species documented in the Mexican dry tropical forests during the 1920s to 1940s were still present. Biostatistical diversity analysis was performed to compare historical to recent data on species occurrences. A data matrix of 577 geographical records was analysed. In total, 374 Athysanini data records were included representing 115 species of 41 genera. Historically, species richness and diversity were higher than found in the recent survey, despite greater collecting effort in the latter. A strong trend in species decline was observed (−53%) over 75 years in this endangered seasonally dry ecosystem. Species completeness was dissimilar between historic and present data. Endemic taxa were significantly less important and represented in the 1920s–1940s species records. All localities surveyed in the dry tropical forest are disturbed and reduced by modern anthropogenic processes. Mexico harbours highly endemic leafhopper taxa with a large proportion of these inhabiting the dry forest. These findings provide important data for conservation decision making and modelling of distribution patterns of this threatened seasonally dry tropical ecosystem.

Climate change will likely threaten areas of suitable habitats for the most relevant medicinal plants native to the Caatinga dry forest

“…One of the unknowns of climate change is that it must also alter people's behaviour, in that systems, so that the use of some plants can be drastically increased throughout their geographical distribution, as will be discussed further below. Studies suggest that the loss of species (plants, mammals and birds, for example) as a consequence of climate change is a trend for dry tropical forests (e.g., Golicher et al 2012;Hidasi-Neto et al 2019;Prieto-Torres et al 2020;Pinedo-Escatel et al 2021). The negative impact of reduced levels of precipitation and recurrent drought events on the species richness of medicinal plants in the dry Caatinga forest agrees with these predictions.…”

Paraulacizes irrorata (Fabricius, 1794) (Hemiptera: Cicadellidae: Cicadellinae: Proconiini) en México, con el primer registro de alimentación sobre Agave salmiana Otto ex Salm-Dyck en Huichapan, Hidalgo, México

“…18), concentrándose en el noroeste y centro del país, esto a consecuencia de los limitados registros existentes en las colecciones y escases de material disponible para estudio. Es importante destacar que este caso en particular es similar al de cientos de otras especies de chicharritas presentes en el territorio mexicano que han sido pobremente estudiadas en los últimos 75 años (Pinedo-Escatel et al 2021a). Las especies vegetales que sirven de refugio u hospedantes en México son aún más desconocidas, y hasta el momento solo se ha logrado identificar a A. salmiana como planta huésped de P. irrotata.…”

“…México alberga poco más de 1.480 especies (McKamey 2002), pero el número preciso aún permanece lejos de estar bien cuantificado. De igual manera, la cantidad de subfamilias que están presentes en el territorio mexicano es desconocida, sin embargo, las contribuciones de Blanco-Rodríguez (2014), Blanco-Rodríguez et al (2022a) y Pinedo-Escatel et al (2021a, 2021b, 2021c, además de las crecientes descripciones de taxones nuevos para el país (Blanco-Rodríguez et al 2022b;Pinedo-Escatel et al 2016; Pinedo-Escatel y Dietrich 2020) ilustran un marco de referencia que puede dar indicios de la magnitud, porvenir y/o representatividad parcial en el país.…”

The Present and Future of Insect Biodiversity Conservation in the Neotropics: Policy Gaps and Recommendations

“…The lack of data in the region can obscure patterns of insect extinction that remain undetected and, thus, unmanageable from the perspective of conservation policies (Janzen and Hallwachs 2019 , 2021 ). Existing data has indeed identified declines in the abundance and diversity of several insect taxa in the Neotropics, including Hymenopterans (Frankie et al 2009 ; Nemésio 2013 ), Lepidopterans (Salcido et al 2020 ), Hemipterans (Pinedo-Escatel et al 2021 ), and aquatic insects (Romero et al 2021 ). This includes, for example, a 53% decline in sap-sucking Hemiptera (tribe: Athysanini) over 75 years in Mexican dry forests (Pinedo-Escatel et al 2021 ).…”

“…Existing data has indeed identified declines in the abundance and diversity of several insect taxa in the Neotropics, including Hymenopterans (Frankie et al 2009 ; Nemésio 2013 ), Lepidopterans (Salcido et al 2020 ), Hemipterans (Pinedo-Escatel et al 2021 ), and aquatic insects (Romero et al 2021 ). This includes, for example, a 53% decline in sap-sucking Hemiptera (tribe: Athysanini) over 75 years in Mexican dry forests (Pinedo-Escatel et al 2021 ). Modelling efforts also indicate the potential for further losses in the face of climatic changes (Fonseca 2009 ; Giannini et al 2012 ; Gonzalez et al 2021 ), which may pose a threat to ecosystem services in the area, including pollination, with up to US$22 billion of crops in Latin America attributed to insect pollinators (Basualdo et al 2022 ).…”