Plant community change in three Mongolian steppe ecosystems 1994–2013: applications to state‐and‐transition models

Abstract

Citation: Jamiyansharav, K., M. E. Fern andez-Gim enez, J. P. Angerer, B. Yadamsuren, and Z. Dash. 2018. Plant community change in three Mongolian steppe ecosystems 1994-2013: applications to state-and-transition models.Ecosphere 9(3):e02145. 10.1002/ecs2.2145Abstract. Interacting effects of climate change and livestock grazing on semi-arid grassland ecosystems have not been well studied, especially on a long-term basis. This paper analyzes changes in plant community composition in relation to grazing intensity and climate change based on repeated monitoring along longterm grazing intensity gradients in three Mongolian ecological zones over 20 yr. We synthesized our findings into state-and-transition models of vegetation change, contributing to our understanding of ecological dynamics in relation to management and environmental change, and to the development of tools for resilience-based rangeland management. In the mountain steppe (MS), community composition was driven largely by climate, and transitions from one community to another were associated with climate change or combined climate and grazing effects. The MS experienced the largest number of long-term transitions (14 of 15 plots) over 20 yr. In the steppe (ST), grazing intensity was the strongest influence on community composition, but transitions between communities from the early 1990s to 2013 were most strongly correlated with climate change. Ten of the 15 ST plots transitioned to other communities over 20 yr. Community composition in the desert steppe (DS) was unrelated to either grazing intensity or climate change and only six of 15 plots transitioned permanently over 20 yr. The MS appears most vulnerable to climate-induced community change, as others have suggested. Some degraded ST communities are resilient to climate change, while ST communities on drier sites are vulnerable to grazing-induced community changes. Our findings illustrate the utility of state-and-transition models as a means to synthesize and depict plant community dynamics in relation to climate and management factors. These models identify communities that may be growing rarer or more common under the combined effects of climate change and grazing, and highlight species and communities that may be useful conservation targets or indicators of climate-or grazing-induced change.

Opportunities to integrate herders’ indicators into formal rangeland monitoring: an example from Mongolia

“…In the ST, ordination analysis showed that plant community composition is associated most strongly with growing‐season precipitation and moderately associated with livestock use, similar to findings of Jamiyansharav et al. (). As in the DS, herders’ assessment scores correlated with the axis 1 and herders tended to give higher scores to Stipa krylovii dominated plots.…”

“…Our finding aligns with other TEK studies conducted in this mesic and more productive zone of Mongolia, where herders also identified heavy grazing is the primary factor influencing rangeland degradation (Kakinuma et al 2008, Bruegger et al 2014. Herder observations in our study and others are consistent with scientific observations that livestock grazing has a strong effect on rangeland condition in this zone (Fernandez-Gimenez and Allen-Diaz 2001, Van Staalduinen et al 2007, Jamiyansharav et al 2018.…”

“…The ST zone appears to demonstrate characteristics of both equilibrium and non-equilibrium dynamics (Fernandez-Gimenez and Allen-Diaz 1999), though recent changes in climate and grazing intensity could be pushing it toward the non-equilibrium end of the continuum (Jamiyansharav et al 2018, Jamsranjav et al 2018. ST herders' observations align with these findings, as they saw rainfall as the main cause of healthy rangelands, and perceived overgrazing as the main driver of degradation.…”

“…The ST zone appears to demonstrate characteristics of both equilibrium and non‐equilibrium dynamics (Fernandez‐Gimenez and Allen‐Diaz ), though recent changes in climate and grazing intensity could be pushing it toward the non‐equilibrium end of the continuum (Jamiyansharav et al. , Jamsranjav et al. ).…”

Ambient changes exceed treatment effects on plant species abundance in global change experiments

“…A growing body of evidence from observational studies of longterm monitoring plots, remotely sensed data, or species range shifts demonstrates that vegetation distribution is responding strongly to environmental change (Doughty et al, 2016;Franklin, Serra-Diaz, Syphard, & Regan, 2016;Jamiyansharav, Fernández-Giménez, Angerer, Yadamsuren, & Dash, 2018;Maguire, Nieto-Lugilde, Fitzpatrick, Williams, & Blois, 2015;Parmesan & Yohe, 2003;Schuster, Martinez, & Dukes, 2014;Simkin et al, 2016). While these studies capture ongoing responses to environmental change, attribution to a particular cause can be difficult (Cudlin et al, 2017), thereby complicating comparisons to manipulative studies.…”