Impacts of land cover change on the plant resources of an endangered pollinator

Abstract

One of the key drivers of pollinator declines is land cover change. We documented for the first time the impacts of over three decades of land cover change in Mexico on the plant resources of an endangered migratory pollinator, the Mexican long-nosed bat, Leptonycteris nivalis. This species is considered endangered under national and international criteria due to population declines over 50% in the past 10 years. Pregnant females of this bat species migrate every year following the blooms of Agave spp. from central Mexico to the southern United States; moving pollen over its 1,200 km long migratory corridor and pollinating distant populations of Agave spp. Increases in human populations density and agricultural expansion may be reducing agave habitat over time. The objective of our study is to understand the land cover change trends in the northern range of the bat and identify potential fragmentation patterns in the region. We analyzed changes that occurred in three vegetation types where agaves are found in five time periods 1985, 1993, 2002, 2007 and 2011. The area of the three vegetation types selected was reduced by using only the overlap with potential agave habitat created with ecological niche modeling algorithms to obtain the available agave habitat. We then calculated fragmentation metrics for each period. We found a significant portion of habitat lost mainly due to expansion in agriculture. The total number of patches increased after 1985. Only 9% of the available agave habitat in 2011 is inside the limits of protected areas. We recommend restoring agave populations in depleted areas to help prevent soil erosion and provide multiple socio-economic benefits for the region in the short term, and, in the long-term maintaining foraging resources for nectar-feeding bats.

Genomic Analyses of Wild and Cultivated Bacanora Agave (Agave angustifolia var. pacifica) Reveal Inbreeding, Few Signs of Cultivation History and Shallow Population Structure

“…The major concern of the current increase of mezcal and related beverage production is that in the eagerness for satisfying ever-growing demand, there could be an unprecedent negative impact on natural habitat and on wild agave populations [ 53 , 83 ]. Currently, it is difficult to evaluate A. angustifolia’s level of genetic diversity in a broader context of Agavoideae species, and it is unclear what levels of diversity and inbreeding should be expected.…”

Genomic analyses of wild and cultivated bacanora agave (Agave angustifoliavar.pacifica) reveal inbreeding, few signs of cultivation history and shallow population structure

“…The major concern of the current increase of mezcal and related beverages production is that in the eagerness of satisfying ever-growing demand, there could be an unprecedent negative impact on natural habitat and on wild agave populations [47,80]. Currently, it is difficult to evaluate A. angustifolia’s level of genetic diversity in a broader context of Agavoideae species, and it is unclear what levels of diversity and inbreeding should be expected.…”

“…The major concern of the current increase of mezcal and related beverages production is that in the eagerness of satisfying ever-growing demand, there could be an unprecedent negative impact on natural habitat and on wild agave populations [47,80]. Currently, it is difficult to evaluate A.…”